% Hellwagner, Hermann % Encoding: utf-8 @InProceedings{Tashtarian2021, author = {Farzad Tashtarian and Abdelhak Bentaleb and Reza Farahani and Minh Nguyen and Christian Timmerer and Hellwagner, Hermann and Roger Zimmermann}, booktitle = {2021 IEEE 46th Conference on Local Computer Networks (LCN)}, title = {{A Distributed Delivery Architecture for User Generated Content Live Streaming over HTTP}}, year = {2021}, month = {oct}, pages = {162--169}, publisher = {IEEE}, abstract = {Live User Generated Content (UGC) has become very popular in today’s video streaming applications, in particular with gaming and e-sport. However, streaming UGC presents unique challenges for video delivery. When dealing with the technical complexity of managing hundreds or thousands of concurrent streams that are geographically distributed, UGC systems are forces to made difficult trade-offs with video quality and latency. To bridge this gap, this paper presents a fully distributed architecture for UGC delivery over the Internet, termed QuaLA (joint Quality-Latency Architecture). The proposed architecture aims to jointly optimize video quality and latency for a better user experience and fairness. By using the proximal Jacobi alternating direction method of multipliers (ProxJ-ADMM) technique, QuaLA proposes a fully distributed mechanism to achieve an appropriate solution. We demonstrate the effectiveness of the proposed architecture through real-world experiments using the CloudLAB testbed. Experimental results show the outperformance of QuaLA in achieving high quality with more than 57% improvement while preserving a good level of fairness and respecting a given target latency among all clients compared to conventional client-driven solutions.}, doi = {10.1109/lcn52139.2021.9525027}, keywords = {UGC streaming, low latency live streaming, fairness, QoE, HAS, DASH, ABR, adaptive streaming, ADMM}, url = {https://ieeexplore.ieee.org/document/9525027} } @InProceedings{Taraghi2021, author = {Babak Taraghi and Abdelhak Bentaleb and Christian Timmerer and Roger Zimmermann and Hellwagner, Hermann}, booktitle = {Proceedings of the 31st ACM Workshop on Network and Operating Systems Support for Digital Audio and Video}, title = {{Understanding quality of experience of heuristic-based HTTP adaptive bitrate algorithms}}, year = {2021}, month = {jul}, pages = {82--89}, publisher = {ACM}, abstract = {Adaptive bitrate (ABR) algorithms play a crucial role in delivering the highest possible viewer's Quality of Experience (QoE) in HTTP Adaptive Streaming (HAS). Online video streaming service providers use HAS - the dominant video streaming technique on the Internet - to deliver the best QoE for their users. A viewer's delight relies heavily on how the ABR of a media player can adapt the stream's quality to the current network conditions. QoE for video streaming sessions has been assessed in many research projects to give better insight into the significant quality metrics such as startup delay and stall events. The ITU Telecommunication Standardization Sector (ITU-T) P.1203 quality evaluation model allows to algorithmically predict a subjective Mean Opinion Score (MOS) by considering various quality metrics. Subjective evaluation is the best assessment method for examining the end-user opinion over a video streaming session's experienced quality. We have conducted subjective evaluations with crowdsourced participants and evaluated the MOS of the sessions using the ITU-T P.1203 quality model. This paper's main contribution is to investigate the correspondence of subjective and objective evaluations for well-known heuristic-based ABRs.}, doi = {10.1145/3458306.3458875}, keywords = {HTTP Adaptive Streaming, ABR Algorithms, Quality of Experience, Crowdsourcing, Subjective Evaluation, Objective Evaluation, MOS}, url = {https://dl.acm.org/doi/10.1145/3458306.3458875} } @Article{Rinner2021, author = {Bernhard Rinner and Christian Bettstetter and Hellwagner, Hermann and Stephan Weiss}, journal = {Computer}, title = {{Multidrone Systems: More Than the Sum of the Parts}}, year = {2021}, issn = {0018-9162}, month = {may}, number = {5}, pages = {34--43}, volume = {54}, abstract = {Now that drones have evolved from bulky platforms to agile devices, a challenge is to combine multiple drones into an integrated autonomous system, offering functionality that individual drones cannot achieve. Such multidrone systems require connectivity, communication, and coordination. We discuss these building blocks along with case studies and lessons learned.}, doi = {10.1109/mc.2021.3058441}, keywords = {Autonomous systems, Drones}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, url = {https://ieeexplore.ieee.org/document/9427128} } @Article{Moll2021, author = {Philipp Moll and Selina Isak and Hellwagner, Hermann and Jeff Burke}, journal = {Computer Networks}, title = {{A Quadtree-based synchronization protocol for inter-server game state synchronization}}, year = {2021}, issn = {1389-1286}, month = {feb}, pages = {107723}, volume = {185}, abstract = {Online games are a fundamental part of the entertainment industry but the current IP infrastructure does not satisfactorily fulfill the needs of these services. The novel networking architecture Named Data Networking (NDN) inherently supports network-level multicast and packet-level security and thereby introduces promising features for online games. In this paper, we propose an NDN-based approach to synchronize game state in a server cluster, a task necessary to allow multiple players in large numbers to play in the same game world. The proposed Quadtree Synchronization Protocol applies NDN’s data-centric nature to decouple the game world from the game servers hosting it. This means that requesting changes of a specific game world region becomes possible without knowing which game server is responsible for the requested region. We use a hierarchic game world structure when requesting data that allows the network to forward requests to the responsible game server without directly addressing it. This region-based naming scheme decouples world regions from servers which eases the management of the game server cluster and allows easier recovery after server failures. In addition, this decoupling allows exchanging information about a geographical region, such as a game world, without knowledge of the other participants changing the world. Such a region-based synchronization mode is not possible to implement with existing protocols. However, it allows building distributed systems that do not require a central server to work. Besides architectural benefits, network emulations show that our protocol increases the efficiency of data transport by utilizing network-level multicast. Our proposed approach can keep up with current protocols which can be used for inter-server game state synchronization.}, doi = {10.1016/j.comnet.2020.107723}, keywords = {Named Data Networking, Distributed dataset synchronization, Online games}, publisher = {Elsevier {BV}}, url = {https://www.sciencedirect.com/science/article/pii/S1389128620313177} } @InProceedings{Lorenzi2021, author = {Daniele Lorenzi and Minh Nguyen and Farzad Tashtarian and Simone Milani and Hellwagner, Hermann and Christian Timmerer}, booktitle = {Proceedings of the 2021 Workshop on Evolution, Performance and Interoperability of QUIC}, title = {{Days of future past}}, year = {2021}, month = {dec}, pages = {8--14}, publisher = {ACM}, abstract = {HTTP Adaptive Streaming (HAS) has become a predominant technique for delivering videos in the Internet. Due to its adaptive behavior according to changing network conditions, it may result in video quality variations that negatively impact the Quality of Experience (QoE) of the user. In this paper, we propose Days of Future Past, an optimization-based Adaptive Bitrate (ABR) algorithm over HTTP/3. Days of Future Past takes advantage of an optimization model and HTTP/3 features, including (i) stream multiplexing and (ii) request cancellation. We design a Mixed Integer Linear Programming (MILP) model that determines the optimal video qualities of both the next segment to be requested and the segments currently located in the buffer. If better qualities for buffered segments are found, the client will send corresponding HTTP GET requests to retrieve them. Multiple segments (i.e., retransmitted segments) might be downloaded simultaneously to upgrade some buffered but not yet played segments to avoid quality decreases using the stream multiplexing feature of QUIC. HTTP/3's request cancellation will be used in case retransmitted segments will arrive at the client after their playout time. The experimental results shows that our proposed method is able to improve the QoE by up to 33.9%.}, doi = {10.1145/3488660.3493802}, keywords = {HTTP/3, QUIC, Days of Future Past, HAS, QoE}, url = {https://dl.acm.org/doi/10.1145/3488660.3493802} } @Article{Kimovski2021c, author = {Dragi Kimovski and Roland Matha and Josef Hammer and Narges Mehran and Hellwagner, Hermann and Radu Prodan}, journal = {IEEE Internet Computing}, title = {{Cloud, Fog, or Edge: Where to Compute?}}, year = {2021}, issn = {1941-0131}, month = {jul}, number = {4}, pages = {30--36}, volume = {25}, abstract = {The computing continuum extends the high-performance cloud data centers with energy-efficient and low-latency devices close to the data sources located at the edge of the network. However, the heterogeneity of the computing continuum raises multiple challenges related to application management. These include where to offload an application – from the cloud to the edge – to meet its computation and communication requirements. To support these decisions, we provide in this article a detailed performance and carbon footprint analysis of a selection of use case applications with complementary resource requirements across the computing continuum over a real-life evaluation testbed.}, doi = {10.1109/mic.2021.3050613}, keywords = {Edge computing, Cloud computing, Benchmarking, Carbon footprint}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, url = {https://ieeexplore.ieee.org/document/9321525} } @InProceedings{Hellwagner2021, author = {Antonia Stornig and Aymen Fakhreddine and Hellwagner, Hermann and Petar Popovski and Christian Bettstetter}, booktitle = {2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)}, title = {{Video Quality and Latency for UAV Teleoperation over {LTE}: A Study with ns3}}, year = {2021}, month = {apr}, pages = {1--7}, publisher = {IEEE}, abstract = {Teleoperation of an unmanned aerial vehicle (UAV) is a challenging mobile application with real-time control from a first-person view. It poses stringent latency requirements for both video and control traffic. This paper studies the video quality and latencies for UAV teleoperation over LTE using ns3 simulations. A key ingredient is the latency budget model. We observe that the latency of the video is higher and more sensitive to mobility than that of the control traffic. The latency is influenced by the traffic variation caused by the variable bit rate of the streaming application. High mobility tends to increase latency and lead to more outliers, being problematic in real-time control.}, doi = {10.1109/vtc2021-spring51267.2021.9448676}, keywords = {Drone, teleoperation, video streaming, ns3, simulation, QoS, QoE}, url = {https://ieeexplore.ieee.org/document/9448676} } @Article{Hayat2021, author = {Samira Hayat and Roland Jung and Hellwagner, Hermann and Christian Bettstetter and Driton Emini and Dominik Schnieders}, journal = {IEEE Robotics and Automation Letters}, title = {{Edge Computing in 5G for Drone Navigation: What to Offload?}}, year = {2021}, issn = {2377-3766}, month = {apr}, number = {2}, pages = {2571--2578}, volume = {6}, abstract = {Small drones that navigate using cameras may be limited in their speed and agility by low onboard computing power. We evaluate the role of edge computing in 5G for such autonomous navigation. The offloading of image processing tasks to an edge server is studied with a vision-based navigation algorithm. Three computation modes are compared: onboard, fully offloaded to the edge, and partially offloaded. Partial offloading is expected to pose lower demands on the communication network in terms of transfer rate than full offloading but requires some onboard processing. Our results on the computation time help select the most suitable mode for image processing, i.e., whether and what to offload, based on the network conditions.}, doi = {10.1109/lra.2021.3062319}, keywords = {Aerial systems, autonomous vehicle navigation, perception and autonomy, vision-based navigation}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, url = {https://ieeexplore.ieee.org/document/9363523} } @InProceedings{Farahani2021a, author = {Reza Farahani and Farzad Tashtarian and Hadi Amirpour and Christian Timmerer and Mohammad Ghanbari and Hellwagner, Hermann}, booktitle = {2021 IEEE 46th Conference on Local Computer Networks (LCN)}, title = {{CSDN: CDN-Aware QoE Optimization in SDN-Assisted HTTP Adaptive Video Streaming}}, year = {2021}, month = {oct}, pages = {525--532}, publisher = {IEEE}, abstract = {Recent studies have revealed that network-assisted techniques, by providing a comprehensive view of the network, improve HTTP Adaptive Streaming (HAS) system performance significantly. This paper leverages the capability of Software-Defined Networking, Network Function Virtualization, and edge computing to introduce a CDN-Aware QoE Optimization in SDN-Assisted Adaptive Video Streaming (CSDN) framework. We employ virtualized edge entities to collect various information items and run an optimization model with a new server/segment selection approach in a time-slotted fashion to serve the clients’ requests by selecting optimal cache servers. In case of a cache miss, a client’s request is served by an optimal replacement quality from a cache server, by a quality transcoded from an optimal replacement quality at the edge, or by the originally requested quality from the origin server. Comprehensive experiments conducted on a large-scale testbed demonstrate that CSDN outperforms other approaches in terms of the users’ QoE and network utilization.}, doi = {10.1109/lcn52139.2021.9524970}, keywords = {Dynamic Adaptive Streaming over HTTP (DASH), Edge Computing, Network-Assisted Video Streaming, Quality of Experience (QoE), Software Defined Networking (SDN), Network Function Virtualization (NFV), Video Transcoding, Content Delivery Network (CDN)}, url = {https://ieeexplore.ieee.org/document/9524970} } @InProceedings{Farahani2021, author = {Reza Farahani and Farzad Tashtarian and Alireza Erfanian and Christian Timmerer and Mohammad Ghanbari and Hellwagner, Hermann}, booktitle = {Proceedings of the 31st ACM Workshop on Network and Operating Systems Support for Digital Audio and Video}, title = {{ES-HAS: an edge- and SDN-assisted framework for HTTP adaptive video streaming}}, year = {2021}, month = {jul}, pages = {50--57}, publisher = {ACM}, abstract = {Recently, HTTP Adaptive Streaming (HAS) has become the dominant video delivery technology over the Internet. In HAS, clients have full control over the media streaming and adaptation processes. Lack of coordination among the clients and lack of awareness of the network conditions may lead to sub-optimal user experience and resource utilization in a pure client-based HAS adaptation scheme. Software Defined Networking (SDN) has recently been considered to enhance the video streaming process. In this paper, we leverage the capability of SDN and Network Function Virtualization (NFV) to introduce an edge- and SDN-assisted video streaming framework called ES-HAS. We employ virtualized edge components to collect HAS clients' requests and retrieve networking information in a time-slotted manner. These components then perform an optimization model in a time-slotted manner to efficiently serve clients' requests by selecting an optimal cache server (with the shortest fetch time). In case of a cache miss, a client's request is served (i) by an optimal replacement quality (only better quality levels with minimum deviation) from a cache server, or (ii) by the original requested quality level from the origin server. This approach is validated through experiments on a large-scale testbed, and the performance of our framework is compared to pure client-based strategies and the SABR system [12]. Although SABR and ES-HAS show (almost) identical performance in the number of quality switches, ES-HAS outperforms SABR in terms of playback bitrate and the number of stalls by at least 70% and 40%, respectively.}, doi = {10.1145/3458306.3460997}, keywords = {Dynamic Adaptive Streaming over HTTP (DASH), Edge Computing, Network-Assisted Video Streaming, Quality of Experience (QoE), Software Defined Networking (SDN), Network Function Virtualization (NFV)}, url = {https://dl.acm.org/doi/10.1145/3458306.3460997} } @InProceedings{Erfanian2021b, author = {Alireza Erfanian and Hadi Amirpour and Farzad Tashtarian and Christian Timmerer and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop on Design, Deployment, and Evaluation of Network-assisted Video Streaming}, title = {{LwTE-Live: Light-weight Transcoding at the Edge for Live Streaming}}, year = {2021}, month = {dec}, pages = {22--28}, publisher = {ACM}, abstract = {Live video streaming is widely embraced in video services, and its applications have attracted much attention in recent years. The increased number of users demanding high quality (e.g., 4K resolution) live videos increases the bandwidth utilization in the backhaul network. To decrease bandwidth utilization in HTTP Adaptive Streaming (HAS), in on-the-fly transcoding approaches, only the highest bitrate representation is delivered to the edge, and other representations are generated by transcoding at the edge. However, this approach is inefficient due to the high transcoding cost. In this paper, we propose a light-weight transcoding at the edge method for live applications, LwTE-Live, to decrease the bandwidth utilization and the overall live streaming cost. During the encoding processes at the origin server, the optimal encoding decisions are saved as metadata and the metadata replaces the corresponding representation in the bitrate ladder. The significantly reduced size of the metadata compared to its corresponding representation decreases the bandwidth utilization. The extracted metadata is then utilized at the edge to decrease the transcoding time. We formulate the problem as a Mixed-Binary Linear Programming (MBLP) model to optimize the live streaming cost, including the bandwidth and computation costs. We compare the proposed model with state-of-the-art approaches, and the experimental results show that our proposed method saves the cost and backhaul bandwidth utilization up to 34% and 45%, respectively.}, doi = {10.1145/3488662.3493829}, url = {https://dl.acm.org/doi/10.1145/3488662.3493829} } @Article{Erfanian2021a, author = {Alireza Erfanian and Hadi Amirpour and Farzad Tashtarian and Christian Timmerer and Hellwagner, Hermann}, journal = {IEEE Access}, title = {{LwTE: Light-Weight Transcoding at the Edge}}, year = {2021}, issn = {2169-3536}, month = aug, pages = {112276--112289}, volume = {9}, abstract = {Due to the growing demand for video streaming services, providers have to deal with increasing resource requirements for increasingly heterogeneous environments. To mitigate this problem, many works have been proposed which aim to ( i ) improve cloud/edge caching efficiency, (ii) use computation power available in the cloud/edge for on-the-fly transcoding, and (iii) optimize the trade-off among various cost parameters, e.g., storage, computation, and bandwidth. In this paper, we propose LwTE, a novel L ight- w eight T ranscoding approach at the E dge, in the context of HTTP Adaptive Streaming (HAS). During the encoding process of a video segment at the origin side, computationally intense search processes are going on. The main idea of LwTE is to store the optimal results of these search processes as metadata for each video bitrate and reuse them at the edge servers to reduce the required time and computational resources for on-the-fly transcoding. LwTE enables us to store only the highest bitrate plus corresponding metadata (of very small size) for unpopular video segments/bitrates. In this way, in addition to the significant reduction in bandwidth and storage consumption, the required time for on-the-fly transcoding of a requested segment is remarkably decreased by utilizing its corresponding metadata; unnecessary search processes are avoided. Popular video segments/bitrates are being stored. We investigate our approach for Video-on-Demand (VoD) streaming services by optimizing storage and computation (transcoding) costs at the edge servers and then compare it to conventional methods (store all bitrates, partial transcoding). The results indicate that our approach reduces the transcoding time by at least 80% and decreases the aforementioned costs by 12% to 70% compared to the state-of-the-art approaches.}, doi = {10.1109/access.2021.3102633}, keywords = {Video Streaming, transcoding, video on demand, edge computing}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, url = {https://ieeexplore.ieee.org/document/9507473} } @Article{Erfanian2021, author = {Alireza Erfanian and Farzad Tashtarian and Anatoliy Zabrovskiy and Christian Timmerer and Hellwagner, Hermann}, journal = {IEEE Transactions on Network and Service Management}, title = {{OSCAR: On Optimizing Resource Utilization in Live Video Streaming}}, year = {2021}, issn = {1932-4537}, month = {mar}, number = {1}, pages = {552--569}, volume = {18}, abstract = {Live video streaming traffic and related applications have experienced significant growth in recent years. However, this has been accompanied by some challenging issues, especially in terms of resource utilization. Although IP multicasting can be recognized as an efficient mechanism to cope with these challenges, it suffers from many problems. Applying software-defined networking (SDN) and network function virtualization (NFV) technologies enable researchers to cope with IP multicasting issues in novel ways. In this article, by leveraging the SDN concept, we introduce OSCAR (Optimizing reSourCe utilizAtion in live video stReaming) as a new cost-aware video streaming approach to provide advanced video coding (AVC)-based live streaming services in the network. In this article, we use two types of virtualized network functions (VNFs): virtual reverse proxy (VRP) and virtual transcoder function (VTF). At the edge of the network, VRPs are responsible for collecting clients’ requests and sending them to an SDN controller. Then, by executing a mixed-integer linear program (MILP), the SDN controller determines a group of optimal multicast trees for streaming the requested videos from an appropriate origin server to the VRPs. Moreover, to elevate the efficiency of resource allocation and meet the given end-to-end latency threshold, OSCAR delivers only the highest requested quality from the origin server to an optimal group of VTFs over a multicast tree. The selected VTFs then transcode the received video segments and transmit them to the requesting VRPs in a multicast fashion. To mitigate the time complexity of the proposed MILP model, we present a simple and efficient heuristic algorithm that determines a near-optimal solution in polynomial time. Using the MiniNet emulator, we evaluate the performance of OSCAR in various scenarios. The results show that OSCAR surpasses other SVC- and AVC-based multicast and unicast approaches in terms of cost and resource utilization.}, doi = {10.1109/tnsm.2021.3051950}, keywords = {Dynamic adaptive streaming over HTTP (DASH), live video streaming, software defined networking (SDN), video transcoding, network function virtualization (NFV)}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, url = {https://ieeexplore.ieee.org/document/9327491} } @InProceedings{Barcis2021a, author = {Michal Barcis and Hellwagner, Hermann}, booktitle = {2021 Wireless Days (WD)}, title = {{Information Distribution in Multi-Robot Systems: Adapting to Varying Communication Conditions}}, year = {2021}, month = {jun}, pages = {1--8}, publisher = {IEEE}, abstract = {This work addresses the problem of application-layer congestion control in multi-robot systems (MRS). It is motivated by the fact that many MRS constrain the amount of transmitted data in order to avoid congestion in the network and ensure that critical messages get delivered. However, such constraints often need to be manually tuned and assume constant network capabilities. We introduce the adaptive goodput constraint, which smoothly adapts to varying communication conditions. It is suitable for long-term communication planning, where rapid changes are undesirable. We analyze the introduced method in a simulation-based study and show its practical applicability using mobile robots.}, doi = {10.1109/wd52248.2021.9508324}, keywords = {Wireless communication, Adaptation models, Adaptive systems, Limiting, Control systems, Data models, Planning}, url = {https://ieeexplore.ieee.org/document/9508324} } @Article{Barcis2021, author = {Michal Barcis and Agata Barcis and Nikolaos Tsiogkas and Hellwagner, Hermann}, journal = {Frontiers in Robotics and AI}, title = {{Information Distribution in Multi-Robot Systems: Generic, Utility-Aware Optimization Middleware}}, year = {2021}, issn = {2296-9144}, month = {jul}, pages = {1--11}, volume = {8}, abstract = {This work addresses the problem of what information is worth sending in a multi-robot system under generic constraints, e.g., limited throughput or energy. Our decision method is based on Monte Carlo Tree Search. It is designed as a transparent middleware that can be integrated into existing systems to optimize communication among robots. Furthermore, we introduce techniques to reduce the decision space of this problem to further improve the performance. We evaluate our approach using a simulation study and demonstrate its feasibility in a real-world environment by realizing a proof of concept in ROS 2 on mobile robots.}, doi = {10.3389/frobt.2021.685105}, keywords = {multi-robot systems, information distribution, adaptive communication, information utility, communication optimization, Monte Carlo tree search}, publisher = {Frontiers Media (SA)}, url = {https://www.frontiersin.org/articles/10.3389/frobt.2021.685105/full} } @InProceedings{AguilarArmijo2021, author = {Jesus Aguilar-Armijo and Christian Timmerer and Hellwagner, Hermann}, booktitle = {2021 IEEE 46th Conference on Local Computer Networks (LCN)}, title = {{EADAS: Edge Assisted Adaptation Scheme for HTTP Adaptive Streaming}}, year = {2021}, month = {oct}, pages = {487--494}, publisher = {IEEE}, abstract = {Mobile networks equipped with edge computing nodes enable access to information that can be leveraged to assist client-based adaptive bitrate (ABR) algorithms in making better adaptation decisions to improve both Quality of Experience (QoE) and fairness. For this purpose, we propose a novel on-the-fly edge mechanism, named EADAS (Edge Assisted Adaptation Scheme for HTTP Adaptive Streaming), located at the edge node that assists and improves the ABR decisions on-the-fly. EADAS proposes (i) an edge ABR algorithm to improve QoE and fairness for clients and (ii) a segment prefetching scheme. The results show a QoE increase of 4.6%, 23.5%, and 24.4% and a fairness increase of 11%, 3.4%, and 5.8% when using a buffer-based, a throughput-based, and a hybrid ABR algorithm, respectively, at the client compared with client-based algorithms without EADAS. Moreover, QoE and fairness among clients can be prioritized using parameters of the EADAS algorithm according to service providers’ requirements.}, doi = {10.1109/lcn52139.2021.9524883}, keywords = {Edge Computing, HTTP Adaptive Streaming, Network-assisted Video Streaming, Quality of Experience}, url = {https://ieeexplore.ieee.org/document/9524883} } @InProceedings{VenkataPhaniKumar2020, author = {Venkata Phani Kumar Malladi and Christian Timmerer and Hellwagner, Hermann}, booktitle = {2020 IEEE International Conference on Multimedia and Expo (ICME)}, title = {{Mipso: Multi-Period Per-Scene Optimization For HTTP Adaptive Streaming}}, year = {2020}, month = {jul}, pages = {1--6}, publisher = {IEEE}, abstract = {Video delivery over the Internet has become more and more established in recent years due to the widespread use of Dynamic Adaptive Streaming over HTTP (DASH). The current DASH specification defines a hierarchical data model for Media Presentation Descriptions (MPDs) in terms of periods, adaptation sets, representations and segments. Although multi-period MPDs are widely used in live streaming scenarios, they are not fully utilized in Video-on-Demand (VoD) HTTP adaptive streaming (HAS) scenarios. In this paper, we introduce MiPSO, a framework for Multi–Period per-Scene Optimization, to examine multiple periods in VoD HAS scenarios. MiPSO provides different encoded representations of a video at either (i) maximum possible quality or (ii) minimum possible bitrate, beneficial to both service providers and subscribers. In each period, the proposed framework adjusts the video representations (resolution-bitrate pairs) by taking into account the complexities of the video content, with the aim of achieving streams at either higher qualities or lower bitrates. The experimental evaluation with a test video data set shows that the MiPSO reduces the average bitrate of streams with the same visual quality by approximately 10% or increases the visual quality of streams by at least 1 dB in terms of Peak Signal-to-Noise (PSNR) at the same bitrate compared to conventional approaches to video content delivery.}, doi = {10.1109/icme46284.2020.9102775}, keywords = {Adaptive Streaming, Video-on-Demand, Per-Scene Encoding, Media Presentation Description}, url = {https://ieeexplore.ieee.org/document/9102775} } @InProceedings{Timmerer2020, author = {Christian Timmerer and Hellwagner, Hermann}, booktitle = {Proceedings of the Brazilian Symposium on Multimedia and the Web}, title = {{HTTP Adaptive Streaming: Where Is It Heading?}}, year = {2020}, month = {nov}, pages = {349--350}, publisher = {ACM}, abstract = {In this contribution, we present selected novel approaches and results of our research work in the ATHENA Christian Doppler Laboratory (Adaptive Streaming over HTTP and Emerging Networked Multimedia Services), a major research project at our department jointly funded by public sources and industry. By putting this work also into the context of related ongoing research activities, we aim at working out where HTTP Adaptive Streaming is currently heading.}, doi = {10.1145/3428658.3434574}, keywords = {HTTP adaptive streaming, video coding, machine learning, edge computing, immersive media, quality of experience}, url = {https://dl.acm.org/doi/10.1145/3428658.3434574} } @InProceedings{Taraghi2020, author = {Babak Taraghi and Anatoliy Zabrovskiy and Christian Timmerer and Hellwagner, Hermann}, booktitle = {Proceedings of the 11th ACM Multimedia Systems Conference}, title = {{Cloud-based Adaptive Video Streaming Evaluation Framework for the Automated Testing of Media Players CAdViSE}}, year = {2020}, month = {may}, pages = {349--352}, publisher = {ACM}, abstract = {Attempting to cope with fluctuations of network conditions in terms of available bandwidth, latency and packet loss, and to deliver the highest quality of video (and audio) content to users, research on adaptive video streaming has attracted intense efforts from the research community and huge investments from technology giants. How successful these efforts and investments are, is a question that needs precise measurements of the results of those technological advancements. HTTP-based Adaptive Streaming (HAS) algorithms, which seek to improve video streaming over the Internet, introduce video bitrate adaptivity in a way that is scalable and efficient. However, how each HAS implementation takes into account the wide spectrum of variables and configuration options, brings a high complexity to the task of measuring the results and visualizing the statistics of the performance and quality of experience. In this paper, we introduce CAdViSE, our Cloud-based Adaptive Video Streaming Evaluation framework for the automated testing of adaptive media players. The paper aims to demonstrate a test environment which can be instantiated in a cloud infrastructure, examines multiple media players with different network attributes at defined points of the experiment time, and finally concludes the evaluation with visualized statistics and insights into the results.}, doi = {10.1145/3339825.3393581}, keywords = {HTTP Adaptive Streaming, Media Players, MPEG-DASH, Network Emulation, Automated Testing, Quality of Experience}, url = {https://dl.acm.org/doi/10.1145/3339825.3393581} } @InProceedings{Nguyen2020a, author = {Minh Nguyen and Christian Timmerer and Hellwagner, Hermann}, booktitle = {Proceedings of the 25th ACM Workshop on Packet Video}, title = {{H2BR: An HTTP/2-based Retransmission Technique to Improve the QoE of Adaptive Video Streaming}}, year = {2020}, month = {jun}, pages = {1--7}, publisher = {ACM}, abstract = {HTTP-based Adaptive Streaming (HAS) plays a key role in over-the-top video streaming. It contributes towards reducing the rebuffering duration of video playout by adapting the video quality to the current network conditions. However, it incurs variations of video quality in a streaming session because of the throughput fluctuation, which impacts the user’s Quality of Experience (QoE). Besides, many adaptive bitrate (ABR) algorithms choose the lowest-quality segments at the beginning of the streaming session to ramp up the playout buffer as soon as possible. Although this strategy decreases the startup time, the users can be annoyed as they have to watch a low-quality video initially. In this paper, we propose an efficient retransmission technique, namely H2BR, to replace low-quality segments being stored in the playout buffer with higher-quality versions by using features of HTTP/2 including (i) stream priority, (ii) server push, and (iii) stream termination. The experimental results show that H2BR helps users avoid watching low video quality during video playback and improves the user’s QoE. H2BR can decrease by up to more than 70% the time when the users suffer the lowest-quality video as well as benefits the QoE by up to 13%.}, doi = {10.1145/3386292.3397117}, keywords = {HTTP adaptive streaming, DASH, ABR algorithms, QoE, HTTP/2}, url = {https://dl.acm.org/doi/abs/10.1145/3386292.3397117} } @InProceedings{Nguyen2020, author = {Minh Nguyen and Hadi Amirpour and Christian Timmerer and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop on the Evolution, Performance, and Interoperability of QUIC}, title = {{Scalable High Efficiency Video Coding based HTTP Adaptive Streaming over QUIC}}, year = {2020}, month = {aug}, pages = {28--34}, publisher = {ACM}, abstract = {HTTP/2 has been explored widely for adaptive video streaming, but still suffers from Head-of-Line blocking, and three-way handshake delay due to TCP. Meanwhile, QUIC running on top of UDP can tackle these issues. In addition, although many adaptive bitrate (ABR) algorithms have been proposed for scalable and non-scalable video streaming, the literature lacks an algorithm designed for both types of video streaming approaches. In this paper, we investigate the impact of QUIC and HTTP/2 on the performance of ABR algorithms. Moreover, we propose an efficient approach for utilizing scalable video coding formats for adaptive video streaming that combines a traditional video streaming approach (based on non-scalable video coding formats) and a retransmission technique. The experimental results show that QUIC benefits significantly from our proposed method in the context of packet loss and retransmission. Compared to HTTP/2, it improves the average video quality and provides a smoother adaptation behavior. Finally, we demonstrate that our proposed method originally designed for non-scalable video codecs also works efficiently for scalable videos such as Scalable High Efficiency Video Coding (SHVC).}, doi = {10.1145/3405796.3405829}, keywords = {QUIC, H2BR, HTTP adaptive streaming, Retransmission, SHVC}, url = {https://dl.acm.org/doi/10.1145/3405796.3405829} } @InProceedings{Messous2020, author = {Mohamed Ayoub Messous and Hellwagner, Hermann and Sidi-Mohammed Senouci and Driton Emini and Dominik Schnieders}, booktitle = {ICC 2020 - 2020 IEEE International Conference on Communications (ICC)}, title = {{Edge Computing for Visual Navigation and Mapping in a UAV Network}}, year = {2020}, month = {jun}, pages = {1--6}, publisher = {IEEE}, abstract = {This research work presents conceptual considerations and quantitative evaluations into how integrating computation offloading to edge computing servers would offer a paradigm shift for an effective deployment of autonomous drones. The specific mission that has been considered is collaborative autonomous navigation and mapping in a 3D environment of a small drone network. Specifically, in order to achieve this mission, each drone is required to compute a low latency, highly compute intensive task in a timely manner. The proposed model decides for each task, while considering the impact on performance and mission requirements, whether to (i) compute locally, (ii) offload to the edge server, or (iii) to the ground station. Extensive simulation work was performed to assess the effectiveness of the proposed scheme compared to other models.}, doi = {10.1109/icc40277.2020.9149087}, keywords = {UAV Network, Edge Computing, Computation Offloading, Visual Navigation and Mapping}, url = {https://ieeexplore.ieee.org/document/9149087} } @InProceedings{Mazdin2020, author = {Petra Mazdin and Michal Barcis and Hellwagner, Hermann and Bernhard Rinner}, booktitle = {2020 IEEE 16th International Conference on Automation Science and Engineering (CASE)}, title = {{Distributed Task Assignment in Multi-Robot Systems based on Information Utility}}, year = {2020}, month = {aug}, pages = {734--740}, publisher = {IEEE}, abstract = {Most multi-robot systems (MRS) require to coordinate the assignment of tasks to individual robots for efficient missions. Due to the dynamics, incomplete knowledge and changing requirements, the robots need to distribute their local state information within the MRS continuously during the mission. Since communication resources are limited and message transfers may be erroneous, the global state estimated by each robot may become inconsistent. This inconsistency may lead to degraded task assignment and mission performance. In this paper, we explore the effect and cost of communication and exploit information utility for online distributed task assignment. In particular, we model the usefulness of the transferred state information by its information utility and use it for controlling the distribution of local state information and for updating the global state. We compare our distributed, utility-based online task assignment with well-known centralized and auction-based methods and show how substantial reduction of communication effort still leads to successful mission completion. We demonstrate our approach in a wireless communication testbed using ROS2.}, doi = {10.1109/case48305.2020.9216982}, keywords = {Task analysis, Robot kinematics, Mathematical model, Multi-robot systems, Optimization, Heuristic algorithms}, url = {https://doi.org/10.1109/CASE48305.2020.9216982} } @InProceedings{Erfanian2020, author = {Alireza Erfanian and Farzad Tashtarian and Reza Farahani and Christian Timmerer and Hellwagner, Hermann}, booktitle = {2020 6th IEEE Conference on Network Softwarization (NetSoft)}, title = {{On Optimizing Resource Utilization in AVC-based Real-time Video Streaming}}, year = {2020}, month = {jun}, pages = {301--309}, publisher = {IEEE}, abstract = {Real-time video streaming traffic and related applications have witnessed significant growth in recent years. However, this has been accompanied by some challenging issues, predominantly resource utilization. IP multicasting, as a solution to this problem, suffers from many problems. Using scalable video coding could not gain wide adoption in the industry, due to reduced compression efficiency and additional computational complexity. The emerging software-defined networking (SDN)and network function virtualization (NFV) paradigms enable re-searchers to cope with IP multicasting issues in novel ways. In this paper, by leveraging the SDN and NFV concepts, we introduce a cost-aware approach to provide advanced video coding (AVC)-based real-time video streaming services in the network. In this study, we use two types of virtualized network functions (VNFs): virtual reverse proxy (VRP) and virtual transcoder (VTF)functions. At the edge of the network, VRPs are responsible for collecting clients’ requests and sending them to an SDN controller. Then, executing a mixed-integer linear program (MILP) determines an optimal multicast tree from an appropriate set of video source servers to the optimal group of transcoders. The desired video is sent over the multicast tree. The VTFs transcode the received video segments and stream to the requested VRPs over unicast paths. To mitigate the time complexity of the proposed MILPmodel, we propose a heuristic algorithm that determines a near-optimal solution in a reasonable amount of time. Using theMiniNet emulator, we evaluate the proposed approach and show it achieves better performance in terms of cost and resource utilization in comparison with traditional multicast and unicast approaches.}, doi = {10.1109/netsoft48620.2020.9165450}, keywords = {Dynamic Adaptive Streaming over HTTP (DASH), Real-time Video Streaming, Software Defined Networking (SDN), Video Transcoding, Network Function Virtualization (NFV)}, url = {https://ieeexplore.ieee.org/document/9165450} } @Article{Barcis2020, author = {Michal Barcis and Agata Barcis and Hellwagner, Hermann}, journal = {Sensors}, title = {{Information Distribution in Multi-Robot Systems: Utility-Based Evaluation Model}}, year = {2020}, issn = {1424-8220}, month = {jan}, number = {3}, volume = {20}, abstract = {This work addresses the problem of information distribution in multi-robot systems, with an emphasis on multi-UAV (unmanned aerial vehicle) applications. We present an analytical model that helps evaluate and compare different information distribution schemes in a robotic mission. It serves as a unified framework to represent the usefulness (utility) of each message exchanged by the robots. It can be used either on its own in order to assess the information distribution efficacy or as a building block of solutions aimed at optimizing information distribution. Moreover, we present multiple examples of instantiating the model for specific missions. They illustrate various approaches to defining the utility of different information types. Finally, we introduce a proof of concept showing the applicability of the model in a robotic system by implementing it in Robot Operating System 2 (ROS 2) and performing a simple simulated mission using a network emulator. We believe the introduced model can serve as a basis for further research on generic solutions for assessing or optimizing information distribution.}, doi = {10.3390/s20030710}, keywords = {autonomous systems, multi-robot systems, information distribution, utility theory}, publisher = {MDPI AG}, url = {https://www.mdpi.com/1424-8220/20/3/710/htm} } @InProceedings{AguilarArmijo2020, author = {Jesus Aguilar-Armijo and Babak Taraghi and Christian Timmerer and Hellwagner, Hermann}, booktitle = {2020 IEEE International Symposium on Multimedia (ISM)}, title = {{Dynamic Segment Repackaging at the Edge for {HTTP} Adaptive Streaming}}, year = {2020}, month = {dec}, pages = {17--24}, publisher = {IEEE}, abstract = {Adaptive video streaming systems typically support different media delivery formats, e.g., MPEG-DASH and HLS, replicating the same content multiple times into the network. Such a diversified system results in inefficient use of storage, caching, and bandwidth resources. The Common Media Application Format (CMAF) emerges to simplify HTTP Adaptive Streaming (HAS), providing a single encoding and packaging format of segmented media content and offering the opportunities of bandwidth savings, more cache hits and less storage needed. However, CMAF is not yet supported by most devices. To solve this issue, we present a solution where we maintain the main advantages of CMAF while supporting heterogeneous devices using different media delivery formats. For that purpose, we propose to dynamically convert the content from CMAF to the desired media delivery format at an edge node. We study the bandwidth savings with our proposed approach using an analytical model and simulation, resulting in bandwidth savings of up to 20% with different media delivery format distributions. We analyze the runtime impact of the required operations on the segmented content performed in two scenarios: the classic one, with four different media delivery formats, and the proposed scenario, using CMAF-only delivery through the network. We compare both scenarios with different edge compute power assumptions. Finally, we perform experiments in a real video streaming testbed delivering MPEG-DASH using CMAF content to serve a DASH and an HLS client, performing the media conversion for the latter one.}, doi = {10.1109/ism.2020.00009}, keywords = {CMAF, Edge Computing, HTTP Adaptive Streaming (HAS)} } @Article{vanderHooft2019, author = {van der Hooft, Jeroen and Torres Vega, Maria and Wauters, Tim and Ravuri, Hemanth Kumar and Timmerer, C. and Hellwagner, Hermann and De Turck, Filip}, journal = {IEEE COMSOC MMTC COMMUNICATIONS - FRONTIERS}, title = {{Towards 6DoF virtual reality video streaming: status and challenges}}, year = {2019}, month = sep, number = {5}, pages = {30--37}, volume = {14}, abstract = {In the last few years, delivery of immersive video with six degrees of freedom (6DoF) has become an important topic for content providers. Recent technological advancements have resulted in affordable head-mounted displays, allowing a broad range of users to enjoy Virtual Reality (VR) content. Service providers such as Facebook1and YouTube2were among the first to provide 360°video, using the principle of HTTP Adaptive Streaming (HAS) to deliver the content to the enduser. In HAS, the content is encoded using several quality representations, temporally segmented into chunks of one to ten seconds and stored on one or multiple servers within a content delivery network. Based on the perceived network conditions, the device characteristics, and the user's preferences, the client can then decide on the quality of each of these segments[1]. Having the ability to adapt the video quality, this approach actively avoids buffer starvation, and therefore results in smoother playback of the requested content and a higher Quality of Experience (QoE) for the end user[2]. The introduction of 360° video provides the user with three degrees of freedom to move within an immersive world, allowing changes in the yaw, roll, and pitch.In the last few years, multiple solutions have been proposed to efficiently deliver VR content through HAS, focusing, for instance, on foveas-and tile-based encoding, improved viewport prediction (i.e., prediction of the user’s head movement in the near future in order to buffer useful high-quality content), and application layer optimizations [3]. In these works, however, the location of the user remains fixed to the position of the camera within the scene. Recently, significant research efforts have been made to realize 6DoF for streamed video content, i.e., the user may experience three additional degrees of freedom by being able to change the viewing position in a video scene. These efforts are promising, but significant research contributions will be required in order to realize its full potential. In this paper, an overview of existing 6DoF solutions is presented, and key challenges and opportunities are highlighted.}, language = {{eng}}, url = {https://biblio.ugent.be/publication/8666820/file/8716606} } @InProceedings{Timmerer2019b, author = {van der Hooft, Jeroen and Wauters, Tim and De Turck, Filip and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 27th ACM International Conference on Multimedia}, title = {{Towards 6dof http adaptive streaming through point cloud compression}}, year = {2019}, month = {Oktober}, pages = {2405--2413}, publisher = {ACM New York}, doi = {10.1145/3343031.3350917}, url = {https://dl.acm.org/citation.cfm?id=3350917} } @Article{Pohl_Hellwagner, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, journal = {IEEE Transactions on Knowledge and Data Engineering}, title = {{Active Online Learning for Social Media Analysis to Support Crisis Management}}, year = {2019}, month = {März}, pages = {1--14}, abstract = {People use social media (SM) to describe and discuss different situations they are involved in, like crises. It is therefore worthwhile to exploit SM contents to support crisis management, in particular by revealing useful and unknown information about the crises in real-time. Hence, we propose a novel active online multiple-prototype classifier, called AOMPC. It identifies relevant data related to a crisis. AOMPC is an online learning algorithm that operates on data streams and which is equipped with active learning mechanisms to actively query the label of ambiguous unlabeled data. The number of queries is controlled by a fixed budget strategy. Typically, AOMPC accommodates partly labeled data streams. AOMPC was evaluated using two types of data: (1) synthetic data and (2) SM data from Twitter related to two crises, Colorado Floods and Australia Bushfires. To provide a thorough evaluation, a whole set of known metrics was used to study the quality of the results. Moreover, a sensitivity analysis was conducted to show the effect of AOMPC's parameters on the accuracy of the results. A comparative study of AOMPC against other available online learning algorithms was performed. The experiments showed very good behavior of AOMPC for dealing with evolving, partly-labeled data streams.}, doi = {10.1109/TKDE.2019.2906173}, url = {https://ieeexplore.ieee.org/document/8669861} } @InProceedings{Moll2019a, author = {Moll, Philipp and Theuermann, Sebastian and Hellwagner, Hermann and Burke, Jeff}, booktitle = {2019 IEEE International Conference on Communications Workshops (ICC Workshops)}, title = {{Distributing the Game State of Online Games: Towards an NDN Version of Minecraft}}, year = {2019}, address = {Piscataway (NJ)}, editor = {Philipp Moll and Sebastian Theuermann and Hellwagner, Hermann and Jeff Burke}, month = {Juli}, publisher = {IEEE}, doi = {10.1109/ICCW.2019.8756979}, url = {https://ieeexplore.ieee.org/document/8756979} } @InProceedings{Moll2019, author = {Moll, Philipp and Theuermann, Sebastian and Rauscher, Natascha Jasmin and Hellwagner, Hermann and Burke, Jeff}, booktitle = {Proceedings of the 6th ACM Conference on Information-Centric Networking (ICN' 19)}, title = {{Inter-Server Game State Synchronization using Named Data Networking}}, year = {2019}, address = {New York, NY}, month = {September}, pages = {12--18}, publisher = {ACM Digital Library}, doi = {10.1145/3357150.3357399}, url = {https://dl.acm.org/citation.cfm?id=3357399} } @InProceedings{Hammer2019, author = {Hammer, Josef and Moll, Philipp and Hellwagner, Hermann}, booktitle = {2019 IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW)}, title = {{Transparent Access to 5G Edge Computing Services}}, year = {2019}, address = {Piscataway (NJ)}, month = {Juli}, pages = {895--898}, publisher = {IEEE}, doi = {10.1109/IPDPSW.2019.00147}, url = {https://ieeexplore.ieee.org/document/8778343} } @InProceedings{Barcis2019, author = {Barcis, Michal and Hellwagner, Hermann}, booktitle = {IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS)}, title = {{An Evaluation Model for Information Distribution in Multi-Robot Systems}}, year = {2019}, month = {September}, pages = {824--829}, doi = {10.1109/INFCOMW.2019.8845299}, url = {https://ieeexplore.ieee.org/document/8845299} } @InProceedings{Moll2018d, author = {Moll, Philipp and Lux, Mathias and Theuermann, Sebastian and Hellwagner, Hermann}, title = {{A Network Traffic and Player Movement Model to Improve Networking for Competitive Online Games}}, booktitle = {Proceedings of the 16th Annual Workshop on Network and Systems Support for Games (NetGames 2018)}, year = {2018}, pages = {1--6}, month = {Juni}, abstract = {}, doi = {}, url = {https://dl.acm.org/citation.cfm?id=3307315}, pdf = {https://www.itec.aau.at/bib/files/a1-moll.pdf} } @InProceedings{Moll2018c, author = {Moll, Philipp and Lux, Mathias and Theuermann, Sebastian and Hellwagner, Hermann}, title = {{A Network Traffic and Player Movement Model to Improve Networking for Competitive Online Games}}, booktitle = {Proceedings of the OAGM Workshop 2018}, year = {2018}, pages = {89--89}, month = {Mai}, abstract = {The popularity of computer games and e-sports is enormously high and still growing every year. Despite the popularity computer games often rely on old technologies, especially in the field of networking. Research in networking for games is challenging due to the low availability of up-todate datasets and network traces. In order to achieve a high user satisfaction while keeping the network activity as low as possible, modern networking solutions of computer games take players’ activities as well as closeness of players in the game world into account. In this paper, we analyze the Battle Royale game mode of the online multiplayer game Fortnite, where 100 players challenge each other in a king-of-the-hill like game within a constantly contracting game world, as an example for a popular online game with demanding technical requirements. We extrapolate player movement patterns by finding player positions automatically from videos, uploaded by Fortnite players on popular streaming platforms and show, how they influence network traffic from the client to the server and vice versa. This extended abstract features the highlights of [1], which has been accepted at the NetGames 2018 event.}, doi = {10.3217/978-3-85125-603-1-17}, url = {http://diglib.tugraz.at/proceedings-of-the-oagm-workshop-2018-2018} } @InProceedings{Moll2018b, author = {Moll, Philipp and Theuermann, Sebastian and Hellwagner, Hermann}, title = {{Wireless Network Emulation for Research on Information-Centric Networking}}, booktitle = {WiNTECH '18 Proceedings of the 12th International Workshop on Wireless Network Testbeds, Experimental Evaluation \& Characterization}, year = {2018}, pages = {46--55}, address = {New York (NY)}, month = {Oktober}, publisher = {ACM Press}, abstract = {When developing new approaches in networking research, one of the most important requirements is to evaluate the degree of improvement of a new approach both realistically and cost-effectively. Wireless networks and their adequate emulation play an important role in evaluation, but emulation of wireless links and networks is still difficult to handle. In this paper, we present a low-cost, fixed-network testbed able to emulate the dynamically changing conditions of wireless links caused by client mobility and physical phenomena. We extend the existing fixed-network testbed for the purpose of wireless network emulation using the Linux tools tc, iptables, and NetEm in sophisticated ways. Convenient function blocks are provided to configure wireless network topologies as well as dynamic link and mobility conditions to be emulated with modest efforts. We utilize the testbed's capabilities to investigate the influence of different mobility models on streaming SVC-encoded videos in Named Data Networking (NDN), a novel Information-Centric Networking architecture. Furthermore, we evaluate the benefits of using early loss detection mechanisms for streaming in NDN, by implementing Wireless Loss Detection and Recovery (WLDR). Our results show that the extended fixed-network testbed can precisely emulate wireless network conditions and usage. For instance, the emulation revealed that both the choice of the mobility model and the use of WLDR have a substantial influence on the resulting SVC video streaming performance.}, doi = {10.1145/3267204.3267211}, url = {https://dl.acm.org/citation.cfm?id=3267211}, pdf = {https://www.itec.aau.at/bib/files/p46-moll.pdf} } @InProceedings{Moll2018a, title = {{Persistent Interests in Named Data Networking}}, author = {Moll, Philipp and Theuermann, Sebastian and Hellwagner, Hermann}, booktitle = {2018 IEEE 87th Vehicular Technology Conference (VTC Spring)}, year = {2018}, address = {Piscataway (NJ)}, month = {Juni}, publisher = {IEEE}, abstract = {Recent research in the field of Information-Centric Networking (ICN) shows the need for push-based data transfer, which is not supported in current pull-based ICN architectures, such as Named Data Networking (NDN). IoT deployments as well as emergency notifications and real-time multimedia communication are well suited to be realized using the ICN principles, but experience challenges in pull-based environments. Persistent Interests (PIs) are a promising approach to introduce pushlike traffic in Interest-based ICN architectures such as NDN. In this paper, we explore the characteristics of PIs and discuss advantages and disadvantages of using them. We provide an efficient solution for preventing so-called Data loops, which are introduced by giving up NDN’s one-request-per-packet principle. Furthermore, we investigate the performance of PIs compared to classical Interests in terms of the computational complexity of forwarding and discuss possible applications of PIs.}, doi = {10.1109/VTCSpring.2018.8417861}, url = {https://ieeexplore.ieee.org/document/8417861/}, pdf = {https://www.itec.aau.at/bib/files/08417861.pdf} } @Article{HH_martina_Dez, author = {Yanmaz, Evsen and Yahyanejad, Saeed and Rinner, Bernhard and Hellwagner, Hermann and Bettstetter, Christian}, journal = {Ad Hoc Networks}, title = {Drone networks: Communications, coordination, and sensing}, year = {2018}, month = {jan}, pages = {1-15}, volume = {68}, abstract = {Small drones are being utilized in monitoring, transport, safety and disaster management, and other domains. Envisioning that drones form autonomous networks incorporated into the air traffic, we describe a high-level architecture for the design of a collaborative aerial system consisting of drones with on-board sensors and embedded processing, coordination, and networking capabilities. We implement a multi-drone system consisting of quadcopters and demonstrate its potential in disaster assistance, search and rescue, and aerial monitoring. Furthermore, we illustrate design challenges and present potential solutions based on the lessons learned so far.}, address = {Amsterdam}, doi = {10.1016/j.adhoc.2017.09.001}, keywords = {Drones, Unmanned aerial vehicle networks, Wireless sensor networks, Vehicular communications, Cooperative aerial imaging, Search and rescue}, language = {EN}, publisher = {Elsevier}, url = {https://www.sciencedirect.com/science/article/pii/S1570870517301671} } @Article{HH_martina, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, journal = {Expert Systems with Applications}, title = {Batch-based active learning: Application to social media data for crisis management}, year = {2018}, month = {mar}, pages = {232-244}, volume = {93}, abstract = {Classification of evolving data streams is a challenging task, which is suitably tackled with online learning approaches. Data is processed instantly requiring the learning machinery to (self-)adapt by adjusting its model. However for high velocity streams, it is usually difficult to obtain labeled samples to train the classification model. Hence, we propose a novel online batch-based active learning algorithm (OBAL) to perform the labeling. OBAL is developed for crisis management applications where data streams are generated by the social media community. OBAL is applied to discriminate relevant from irrelevant social media items. An emergency management user will be interactively queried to label chosen items. OBAL exploits the boundary items for which it is highly uncertain about their class and makes use of two classifiers: k-Nearest Neighbors (kNN) and Support Vector Machine (SVM). OBAL is equipped with a labeling budget and a set of uncertainty strategies to identify the items for labeling. An extensive analysis is carried out to show OBAL’s performance, the sensitivity of its parameters, and the contribution of the individual uncertainty strategies. Two types of datasets are used: synthetic and social media datasets related to crises. The empirical results illustrate that OBAL has a very good discrimination power.}, address = {Amsterdam}, doi = {10.1016/j.eswa.2017.10.026}, language = {EN}, publisher = {Elsevier Ltd.}, url = {http://www.sciencedirect.com/science/article/pii/S095741741730708X} } @Article{Ge2018, author = {Ge, Chang and Wang, Ning and Koong Chai, Wei and Hellwagner, Hermann}, title = {{QoE-Assured 4K HTTP Live Streaming via Transient Segment Holding at Mobile Edge}}, journal = {IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS}, year = {2018}, volume = {36}, number = {8}, pages = {1816--1830}, month = {Juli}, abstract = {HTTP-based live streaming has become increasingly popular in recent years, and more users have started generating 4K live streams from their devices (e.g., mobile phones) through social-media service providers like Facebook or YouTube. If the audience is located far from a live stream source across the global Internet, TCP throughput becomes substantially suboptimal due to slow start and congestion control mechanisms. This is especially the case when the end-to-end content delivery path involves radio access network at the last mile. As a result, the data rate perceived by a mobile receiver may not meet the high requirement of 4K video streams, which causes deteriorated quality-of-experience (QoE). In this paper, we propose a scheme named edge-based transient holding of live segment (ETHLE), which addresses the above-mentioned issue by performing context-aware transient holding of video segments at the mobile edge with virtualized content caching capability. Through holding the minimum number of live video segments at the mobile edge cache in a context-aware manner, the ETHLE scheme is able to achieve seamless 4K live streaming experiences across the global Internet by eliminating buffering and substantially reducing initial startup delay and live stream latency. It has been deployed as a virtual network function at an LTE-A network, and its performance has been evaluated using real live stream sources that are distributed around the world. The significance of this paper is that by leveraging virtualized caching resources at the mobile edge, we address the conventional transport-layer bottleneck and enable QoE-assured Internet-wide live streaming services with high data rate requirements.}, doi = {10.1109/JSAC.2018.2845000}, url = {https://ieeexplore.ieee.org/abstract/document/8374847}, pdf = {https://www.itec.aau.at/bib/files/08374847.pdf} } @InProceedings{martinadez2017, author = {Beck, Harald and Bierbaumer, Bruno and Dao-Tran, Minh and Eiter, Thomas and Hellwagner, Hermann and Schekotihin, Konstantin}, booktitle = {Communications (ICC), 2017 IEEE International Conference on}, title = {Stream Reasoning-Based Control of Caching Strategies in CCN Routers}, year = {2017}, address = {Paris, France}, editor = {Beylat, Jean Luc and Sari, Hikmet}, month = {may}, pages = {6}, publisher = {IEEE}, abstract = {Routers in Content-Centric Networking (CCN) may locally cache frequently requested content in order to speed up delivery to end users. Thus, the issue of caching strategies arises, i.e., which content shall be stored and when it should be replaced. In this work, we employ, and study the feasibility of, novel techniques towards intelligent control of CCN routers that autonomously switch between existing caching strategies in response to changing content request patterns. In particular, we present a router architecture for CCN networks that is controlled by rule-based stream reasoning, following the recent formal framework LARS which extends Answer Set Programming for streams. The obtained possibility for flexible router configuration at runtime allows for versatile network control schemes and may help advance the further development of CCN. Moreover, the empirical evaluation of our feasibility study shows that the resulting caching agent may give significant performance gains.}, doi = {10.1109/ICC.2017.7996762}, isbn10 = {978-1-4673-8999-0}, issn = {1938-1883}, keywords = {Cognition, Internet, Switches, Next generation networking, Programming, Computer architecture, Robots}, language = {EN}, location = {Paris}, talkdate = {2017.05.23}, talktype = {registered} } @Article{Rainer2017a, author = {Rainer, Benjamin and Petscharnig, Stefan and Timmerer, Christian and Hellwagner, Hermann}, journal = {IEEE Transactions on Multimedia}, title = {Statistically Indifferent Quality Variation: An Approach for Reducing Multimedia Distribution Cost for Adaptive Video Streaming Services}, year = {2017}, month = {mar}, pages = {13}, volume = {19}, abstract = {Forecasts predict that Internet traffic will continue to grow in the near future. A huge share of this traffic is caused by multimedia streaming. The Quality of Experience (QoE) of such streaming services is an important aspect and in most cases the goal is to maximize the bit rate which -- in some cases -- conflicts with the requirements of both consumers and providers. For example, in mobile environments users may prefer a lower bit rate to come along with their data plan. Likewise, providers aim at minimizing bandwidth usage in order to reduce costs by transmitting less data to users while maintaining a high QoE. Today's adaptive video streaming services try to serve users with the highest bit rates which consequently results in high QoE. In practice, however, some of these high bit rate representations may not differ significantly in terms of perceived video quality compared to lower bit rate representations. In this paper, we present a novel approach to determine the statistically indifferent quality variation (SIQV) of adjacent video representations for adaptive video streaming services by adopting standard objective quality metrics and existing QoE models. In particular, whenever the quality variation between adjacent representations is imperceptible from a statistical point of view, the representation with higher bit rate can be substituted with a lower bit rate representation. As expected, this approach results in savings with respect to bandwidth consumption while still providing a high QoE for users. The approach is evaluated subjectively with a crowdsourcing study. Additionally, we highlight the benefits of our approach, by providing a case study that extrapolates possible savings for providers.}, address = {New York, USA}, doi = {10.1109/TMM.2016.2629761}, keywords = {Adaptive Video Streaming, Quality of Experience, MPEG-DASH}, language = {EN}, publisher = {IEEE}, url = {http://ieeexplore.ieee.org/document/7745907/} } @Article{Posch2017a, author = {Posch, Daniel and Rainer, Benjamin and Hellwagner, Hermann}, journal = {IEEE/ACM Transactions on Networking}, title = {SAF: Stochastic Adaptive Forwarding in Named Data Networking}, year = {2017}, month = {apr}, number = {2}, pages = {14}, volume = {25}, abstract = {Forwarding decisions in classical IP-based networks are predetermined by routing. This is necessary to avoid loops, inhibiting opportunities to implement an adaptive and intelligent forwarding plane. Consequently, content distribution efficiency is reduced due to a lack of inherent multi-path transmission. In Named Data Networking (NDN) instead, routing shall hold a supporting role to forwarding, providing sufficient potential to enhance content dissemination at the forwarding plane. In this paper we design, implement, and evaluate a novel probability-based forwarding strategy, called Stochastic Adaptive Forwarding (SAF) for NDN. SAF imitates a self-adjusting water pipe system, intelligently guiding and distributing Interests through network crossings circumventing link failures and bottlenecks. Just as real pipe systems, SAF employs overpressure valves enabling congested nodes to lower pressure autonomously. Through an implicit feedback mechanism it is ensured that the fraction of the traffic forwarded via congested nodes decreases. By conducting simulations we show that our approach outperforms existing forwarding strategies in terms of the Interest satisfaction ratio in the majority of the evaluated scenarios. This is achieved by extensive utilization of NDN's multipath and content-lookup capabilities without relying on the routing plane. SAF explores the local environment by redirecting requests that are likely to be dropped anyway. This enables SAF to identify new paths to the content origin or to cached replicas, circumventing link failures and resource shortages without relying on routing updates.}, address = {New York, USA}, doi = {10.1109/TNET.2016.2614710}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/saf.pdf}, publisher = {IEEE}, url = {https://dx.doi.org/10.1109/TNET.2016.2614710} } @Article{Posch2017, author = {Posch, Daniel and Rainer, Benjamin and Hellwagner, Hermann}, journal = {Computer Communication Review}, title = {Towards a Context-Aware Forwarding Plane in Named Data Networking supporting QoS}, year = {2017}, month = {jan}, number = {1}, pages = {9}, volume = {47}, abstract = {The emergence of Information-Centric Networking (ICN) provides considerable opportunities for context-aware data distribution in the network's forwarding plane. While packet forwarding in classical IP-based networks is basically predetermined by routing, ICN foresees an adaptive forwarding plane considering the requirements of network applications. As research in this area is still at an early stage, most of the work so far focused on providing the basic functionality, rather than on considering the available context information to improve Quality of Service (QoS). This article investigates to which extent existing forwarding strategies take account of the available context information and can therefore increase service quality. The article examines a typical scenario encompassing different user applications (Voice over IP, video streaming, and classical data transfer) with varying demands (context), and evaluates how well the applications' requirements are met by the existing strategies.}, address = {New York, USA}, doi = {10.1145/3041027.3041029}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/ccr.pdf}, publisher = {ACM SIGCOMM}, url = {https://dl.acm.org/citation.cfm?doid=3041027.3041029} } @InProceedings{Moll2017a, author = {Moll, Philipp and Posch, Daniel and Hellwagner, Hermann}, booktitle = {Proceedings of the IEEE International Conference on Multimedia and Expo Workshops (ICMEW) 2017}, title = {Investigation of push-based traffic for conversational services in Named Data Networking}, year = {2017}, address = {Hong Kong}, editor = {Pesquet-Popescu,Beatrice and Ngo,Chong-Wah}, month = {jul}, pages = {315-320}, publisher = {IEEE}, abstract = {Conversational services (e.g., Internet telephony) exhibit hard Quality of Service (QoS) requirements, such as low delay and jitter. Current IP-based solutions for conversational services use push-based data transfer only, since pull-based communication as envisaged in Named Data Networking (NDN) suffers from the two-way delay. Unfortunately, IP's addressing scheme requires additional services for contacting communication partners. NDN provides an inherent solution for this issue by using a location-independent naming scheme. Nevertheless, it currently does not provide a mechanism for push-based data transfer. In this paper, we investigate Persistent Interests as a solution for push-based communication. We improve and implement the idea of Persistent Interests, and study their applicability for conversational services in NDN. This is done by comparing different push- and pull-based approaches for Internet telephony.}, doi = {10.1109/ICMEW.2017.8026212}, isbn13 = {978-1-5386-0560-8}, language = {EN}, location = {Hong Kong}, pdf = {https://www.itec.aau.at/bib/files/MuSIC_2017.pdf}, talkdate = {2017.07.10}, talktype = {registered}, url = {http://ieeexplore.ieee.org/document/8026212/} } @InProceedings{Moll2017, author = {Moll, Philipp and Janda, Julian and Hellwagner, Hermann}, booktitle = {Proceedings of the 4th ACM Conference on Information-Centric Networking}, title = {Adaptive Forwarding of Persistent Interests in Named Data Networking}, year = {2017}, address = {New York, NY, USA}, editor = {Schmidt, Thomas C and Seedorf, Jan}, month = {sep}, pages = {180-181}, publisher = {ACM}, abstract = {Persistent Interests (PIs) are a promising approach to introduce push-type traffic in Named Data Networking (NDN), in particular for conversational services such as voice and video calls. Forwarding decisions for PIs are crucial in NDN because they establish a long-lived path for the data flowing back toward the PI issuer. In the course of studying the use of PIs in NDN, we investigate adaptive PI forwarding and present a strategy combining regular NDN forwarding information and results from probing potential alternative paths through the network. Simulation results indicate that our adaptive PI forwarding approach is superior to the PI-adapted Best Route strategy when network conditions change due to link failures.}, doi = {10.1145/3125719.3132091}, isbn13 = {978-1-4503-5122-5}, language = {EN}, location = {Berlin, Germany}, pdf = {https://www.itec.aau.at/bib/files/ACM-ICN-2017_Poster.pdf}, talkdate = {2017.09.27}, talktype = {registered}, url = {http://dl.acm.org/citation.cfm?id=3132091} } @Article{HHmartina2017, author = {Zhu, X and Mao, S and Hassan, M Hassan and Hellwagner, Hermann}, journal = {IEEE Transactions on Multimedia}, title = {Guest Editorial: Video Over Future Networks}, year = {2017}, issn = {1941-0077}, month = {oct}, number = {10}, pages = {2133 - 2135}, volume = {19}, abstract = {The papers in this special issue focus on the deployment of video over future networks. The past decade has seen how major improvements in broadband and mobile networks have led to widespread popularity of video streaming applications, and how the latter now becomes the major driving force behind exponentially growing Internet traffic. This special issue seeks to investigate these future Internet technologies through the prism of its most prevalent application, that of video communications. video.}, address = {Piscataway, NJ}, doi = {10.1109/TMM.2017.2743638}, keywords = {Special issues and sections, Streaming media, Mobile communication, Network architecture, Quality of experience, Ultra-high definition video}, language = {EN}, publisher = {IEEE}, url = {http://ieeexplore.ieee.org/document/8038904/} } @Article{Rainer2016a, author = {Rainer, Benjamin and Posch, Daniel and Leibetseder, Andreas and Theuermann, Sebastian and Hellwagner, Hermann}, journal = {Communications Magazine, IEEE}, title = {A Low-Cost NDN Testbed on Banana Pi Routers}, year = {2016}, month = sep, number = {9}, pages = {6}, volume = {54}, abstract = {The computer communication research community shows significant interest in the paradigm of Information-Centric Networking (ICN). Continuously, new proposals for ICN-related challenges (caching, forwarding, etc.) are published. However, due to a lack of a readily available testbed, the majority of these proposals is evaluated either by theoretical analysis and/or by conducting network simulations potentially masking further challenges that are not observable in synthetic environments. Therefore, this article presents a framework for an ICN testbed using low-budget physical hardware with little deployment and maintenance effort for the individual researcher; specifically, Named Data Networking is considered. The employed hardware and software are powerful enough for most research projects, but extremely resource intensive tasks may push both components towards their limits. The testbed framework is based on well established open source software and provides the tools to readily investigate important ICN characteristics on physical hardware emulating arbitrary network topologies. The article discusses the testbed architecture and provides first results obtained from emulations that investigate the performance of various forwarding strategies. The results indicate that further challenges have to be overcome when heading towards a real-world deployment of ICN-based communication.}, address = {New York, USA}, keywords = {ICN}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/commmagRainer.pdf}, publisher = {IEEE} } @Article{Rainer2016, author = {Rainer, Benjamin and Posch, Daniel and Hellwagner, Hermann}, journal = {Journal on Selected Areas in Communications}, title = {Investigating the Performance of Pull-based Dynamic Adaptive Streaming in NDN}, year = {2016}, issn = {1558-0008}, month = {aug}, number = {8}, pages = {11}, volume = {34}, abstract = {Adaptive content delivery is the state-of-the-art in real-time multimedia streaming. Leading streaming approaches, e.g., MPEG-DASH and Apple HLS, have been developed for classical IP-based networks, providing effective streaming by means of pure client-based control and adaptation. However, the research activities of the Future Internet community adopt a new course that is different from today's host-based communication model. So-called Information-Centric Networks are of considerable interest and are advertised as enablers for intelligent networks, where effective content delivery is to be provided as an inherent network feature. This paper investigates the performance gap between pure client-driven adaptation and the theoretical optimum in the promising Future Internet architecture Named Data Networking (NDN). The theoretical optimum is derived by modeling multimedia streaming in NDN as a fractional Multi-Commodity Flow Problem and by extending it taking caching into account. We investigate the multimedia streaming performance under different forwarding strategies, exposing the interplay of forwarding strategies and adaptation mechanisms. Furthermore, we examine the influence of network inherent caching on the streaming performance by varying the caching polices and the cache sizes.}, address = {New York, USA}, doi = {10.1109/JSAC.2016.2577365}, keywords = {Information-Centric Networking; Named Data Networking; Multimedia; Dynamic Adaptive Streaming.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/jsac.pdf}, publisher = {IEEE} } @InProceedings{Posch2016, author = {Posch, Daniel and Rainer, Benjamin and Theuermann, Sebastian and Leibetseder, Andreas and Hellwagner, Hermann}, booktitle = {Proceedings of the 7th International Conference on Multimedia Systems}, title = {Emulating NDN-based Multimedia Delivery}, year = {2016}, address = {New York}, editor = {Timmerer, Christian and Begen, Ali}, month = {may}, pages = {4}, publisher = {ACM Digital Library}, series = {MMSys '16}, abstract = {Today, the global share and increase of Internet traffic is largely caused by multimedia delivery, mainly encompassing video, audio and image sharing on social, news, and entertainment platforms. This fact is well known to the Internet research community, which tries to counteract by increasing the content delivery efficiency. So-called Information-Centric Networks (ICN) are of considerable interest, advertised as enablers for intelligent networks, where effective delivery is to be provided as an inherent network feature. Most research proposals in this area are evaluated in simulated environments, using simulation frameworks such as OMNeT++ or ns-3. However, simulations always have shortcomings and cannot substitute measurements in physical networks. In this demonstration, we show how to readily set up an ICN-based testbed using low-budget single-board computers to conduct comprehensive emulations. We choose the scenario of pull-based adaptive video delivery as a showcase and evaluate the performance of different client-based adaptation mechanisms at the application level and different content forwarding strategies at the network level. All of the presented tools and visualization features are provided as open source contributions to the community.}, doi = {10.1145/2910017.2910626}, isbn13 = {978-1-4503-4297-1}, keywords = {Named Data Networking, Information-Centric Networking, Network Emulation, Adaptive Multimedia Delivery, Testbed}, language = {EN}, location = {Klagenfurt, Austria}, pdf = {https://www.itec.aau.at/bib/files/pi-demo.pdf}, talkdate = {2016.05.11}, talktype = {poster}, url = {http://doi.acm.org/10.1145/2910017.2910626} } @InProceedings{Martina_HH_Jan18, author = {Beck, Harald and Bierbaumer, Bruno and Dao-Tran, Minh and Eiter, Thomas and Hellwagner, Hermann and Shekotihin, Konstantin}, booktitle = {Proceedings of 15th European Conference on Logics in Artificial Intelligence (JELIA) 2016}, title = {Rule-based Stream Reasoning for Intelligent Administration of Content-Centric Networks}, year = {2016}, address = {Cyprus}, editor = {Michael, Loizos and C Kakas, Antonis}, month = {nov}, pages = {522-528}, publisher = {Springer}, abstract = {Content-Centric Networking (CCN) research addresses the mismatch between the modern usage of the Internet and its outdated architecture. Importantly, CCN routers use various caching strategies to locally cache content frequently requested by end users. However, it is unclear which content shall be stored and when it should be replaced. In this work, we employ novel techniques towards intelligent administration of CCN routers. Our approach allows for autonomous switching between existing strategies in response to changing content request patterns using rule-based stream reasoning framework LARS which extends Answer Set Programming for streams. The obtained possibility for flexible router configuration at runtime allows for faster experimentation and may result in significant performance gains, as shown in our evaluation.}, doi = {10.1007/978-3-319-48758-8_34}, language = {EN}, location = {Cyprus}, talkdate = {2016.11.10}, talktype = {registered} } @InProceedings{Kreuzberger2016a, author = {Kreuzberger, Christian and Rainer, Benjamin and Hellwagner, Hermann and Toni, Laura and Frossard, Pascal}, booktitle = {Proceedings of the 26th International Workshop on Network and Operating Systems Support for Digital Audio and Video}, title = {A Comparative Study of DASH Representation Sets Using Real User Characteristics}, year = {2016}, address = {New York, NY, USA}, editor = {ACM,}, month = {may}, pages = {4:1--4:6}, publisher = {ACM}, isbn10 = {978-1-4503-4356-5}, language = {EN}, location = {Klagenfurt, Austria}, talkdate = {2016.05.13}, talktype = {registered} } @InProceedings{Hermann2016, author = {Yanmaz, Evsen and Quaritsch, Markus and Yahyanejad, Saeed and Rinner, Bernhard and Hellwagner, Hermann and Bettstetter, Christian}, booktitle = {Proceedings of the EAI International Conference on Ad Hoc Networks (ADHOCNETS)}, title = {Communication and Coordination for Drone Networks}, year = {2016}, address = {Ottawa, Canada}, editor = {Yifeng, Zhou and Thomas, Kunz}, month = {sep}, pages = {79-91}, publisher = {Springer Verlag}, abstract = {Small drones are being utilized in monitoring, delivery of goods, public safety, and disaster management among other civil applications. Due to their sizes, capabilities, payload limitations, and limited flight time, it is not far-fetched to expect multiple networked and coordinated drones incorporated into the air traffic. In this paper, we describe a high-level architecture for the design of a collaborative aerial system that consists of drones with on-board sensors and embedded processing, sensing, coordination, and communication&networking capabilities. We present a multi-drone system consisting of quadrotors and demonstrate its potential in a disaster assistance scenario. Furthermore, we illustrate the challenges in the design of drone networks and present potential solutions based on the lessons we have learned so far.}, doi = {10.1007/978-3-319-51204-4_7}, isbn13 = {978-3-319-51203-7}, keywords = {drones, unmanned aerial vehicle networks, wireless sensor networks, vehicular communications, cooperative aerial imaging}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Yanmaz_ADHOCNETS2016.pdf}, talktype = {none}, url = {http://link.springer.com/chapter/10.1007/978-3-319-51204-4_7} } @Article{martina_for_HH, author = {Sterca, Adrian and Hellwagner, Hermann and Boian, Florian and Vancea, Alexandru}, journal = {IEEE Transactions on Circuits and Systems for Video Technology}, title = {Media-friendly and TCP-friendly Rate Control Protocols for Multimedia Streaming}, year = {2015}, month = {aug}, number = {1}, pages = {15}, volume = {1}, abstract = {This paper describes a design framework for TCPfriendly and media-friendly rate control algorithms for multimedia streaming applications. The idea of this framework is to start from TFRC’s (TCP-Friendly Rate Control) transmission rate and then alter this transmission rate so that it tracks the media characteristics of the stream (e.g., bitrate) or other application characteristics like the client buffer fill level. In this way, the media-friendly property of the algorithm is achieved. We give three rules that guide how the TFRC throughput should track the evolution of the stream’s media characteristics and remain TCPfriendly in the long term. We also present, as proof of concept, four simple media-friendly and TCP-friendly congestion control algorithms built using the aforementioned framework. These congestion control algorithms are better suited for multimedia streaming applications than traditional TCP congestion control or smooth congestion control algorithms like TFRC. We have performed evaluations of two of the four proposed media-friendly and TCP-friendly congestion control algorithms under various network conditions and validated that they represent viable transport solutions, better than TFRC, for variable bitrate video streams. More specifically, our two media-friendly and TCPfriendly congestion control algorithms maintained a TCP-friendly throughput in the long term in all experiments and avoided an empty buffer at the client side in situations when TFRC could not achieve this.}, address = {USA}, doi = {10.1109/TCSVT.2015.2469075}, keywords = {TCP-friendly congestion control, media-friendly, multimedia streaming, Bandwidth, Multimedia communication}, language = {EN}, publisher = {IEEE}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=7206573&sortType%3Dasc_p_Sequence%26filter%3DAND%28p_Publication_Number%3A76%29%26rowsPerPage%3D100} } @InProceedings{martina4HH, author = {Scherer, Jürgen and Yahyanejad, Saeed and Hayat, Samira and Yanmaz, Evsen and Andre, Torsten and Khan, Asif and Vukadinovic, Vladimir and Bettstetter, Christian and Hellwagner, Hermann and Rinner, Bernhard}, booktitle = {Proceedings of the First Workshop on Micro Aerial Vehicle Networks, Systems, and Applications for Civilian Use}, title = {An Autonomous Multi-UAV System for Search and Rescue}, year = {2015}, address = {New York, USA}, editor = {Chen, Kuan-Ta and Gerla, Mario and Hummel, Karin Anna and Palazzi, Claudio and Pollin, Sofie and Sterbenz, James JP}, month = {may}, pages = {33-38}, publisher = {ACM}, abstract = {This paper proposes and evaluates a modular architecture of an autonomous unmanned aerial vehicle (UAV) system for search and rescue missions. Multiple multicopters are coordinated using a distributed control system. The system is implemented in the Robot Operating System (ROS) and is capable of providing a real-time video stream from a UAV to one or more base stations using a wireless communications infrastructure. The system supports a heterogeneous set of UAVs and camera sensors. If necessary, an operator can interfere and reduce the autonomy. The system has been tested in an outdoor mission serving as a proof of concept. Some insights from these tests are described in the paper.}, doi = {10.1145/2750675.2750683}, language = {EN}, talktype = {none}, url = {http://delivery.acm.org/10.1145/2760000/2750683/p33-scherer.pdf?ip=143.205.122.208&id=2750683&acc=ACTIVE%20SERVICE&key=9074CF143665B1C6.EF9309C4544B4D37.4D4702B0C3E38B35.4D4702B0C3E38B35&CFID=736686875&CFTOKEN=42529581&__acm__=1449667683_6d2e816f622de719bc19fd2f077632c2} } @InProceedings{Rain1502:IDMSQoMEX, author = {Rainer, Benjamin and Petscharnig, Stefan and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Seventh International Workshop on Quality of Multimedia Experience (QoMEX 2015)}, title = {Is One Second Enough? - Evaluating QoE for Inter-Destination Multimedia Synchronization using Human Computation and Crowdsourcing}, year = {2015}, address = {Greece, Messinia}, editor = {Skodras, Athanassios}, month = {may}, pages = {1-6}, publisher = {IEEE}, abstract = {Modern-age technology enables us to consume multimedia for enjoyment and as a social experience. The traditional way to consume multimedia together (e.g., with family or friends in the living room) is being superseded by a location-independent scenario where geographically distributed users consume the same content while having a real-time communication channel among each other. Inter-Destination Multimedia Synchronization (IDMS) is the tool of choice in order to enable users a high-quality multimedia experience. In this paper, we investigate the influence of asynchronism when consuming multimedia content together while being geographically distributed. In particular, we adopt the concept of human computation and developed a reaction game which we used to conduct a crowdsourced subjective quality assessment in order to evaluate a threshold for multimedia synchronization within an IDMS scenario. Our results show a significant decrease in overall Quality of Experience (QOE) at an asynchronism level of 750ms. At the same time, we were able to show that asynchronism at a level of 400ms does not have significant differences regarding the QoE when compared to the synchronous reference case.}, language = {EN}, location = {Greece, Messinia, Costa Navarino}, pdf = {https://www.itec.aau.at/bib/files/07148107.pdf}, talkdate = {2015.05.27}, talktype = {registered} } @InProceedings{Raffelsberger2015, author = {Raffelsberger, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 13th IEEE International Conference on Pervasive Computing and Communications Workshops ({PerCom Workshops '15})}, title = {A Multimedia Delivery System for Delay-/Disruption-Tolerant Networks}, year = {2015}, address = {Los Alamitos, CA, USA}, editor = {Hurson, Ali and Das, Sajal K}, month = {mar}, pages = {530-536}, publisher = {IEEE}, abstract = {Multimedia delivery systems and protocols usually assume end-to-end connections and low delivery delays between multimedia sources and consumers. However, neither of these two properties can always be achieved in hastily formed networks for emergency response operations. In particular, disruptions may break end-to-end connections, which makes it impossible to deliver multimedia content instantly. This work presents a multimedia delivery system that can operate in disrupted networks and hence may help improve the situational awareness in emergency response operations. The multimedia delivery system is based on HTTP adaptive streaming (HAS) and uses a modified version of HTTP which is able to deliver data in partitioned networks. The multimedia delivery system is evaluated in a realistic emergency response scenario.}, doi = {10.1109/PERCOMW.2015.7134093}, isbn10 = {978-1-4799-8425-1}, language = {EN}, location = {Saint Louis, MO, USA}, pdf = {https://www.itec.aau.at/bib/files/CR-PerNEM15.pdf}, talkdate = {2015.03.27}, talktype = {registered} } @Article{Pohl2015b, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, journal = {Neurocomputing}, title = {Online Indexing and Clustering of Social Media Data for Emergency Management}, year = {2015}, month = {jan}, pages = {168-179}, abstract = {Social media becomes a vital part in our daily communication practice, creating a huge amount of data and covering different real-world situations. Currently, there is a tendency in making use of social media during emergency management and response. Most of this effort is performed by a huge number of volunteers browsing through social media data and preparing maps that can be used by professional first responders. Automatic analysis approaches are needed to directly support the response teams in monitoring and also understanding the evolution of facts in social media during an emergency situation. In this paper, we investigate the problem of real-time sub-events identification in social media data (i.e., Twitter, Flickr and YouTube) during emergencies. A processing framework is presented serving to generate situational reports/summaries from social media data. This framework relies in particular on online indexing and online clustering of media data streams. Online indexing aims at tracking the relevant vocabulary to capture the evolution of sub-events over time. Online clustering, on the other hand, is used to detect and update the set of sub-events using the indices built during online indexing. To evaluate the framework, social media data related to Hurricane Sandy 2012 was collected and used in a series of experiments. In particular some online indexing methods have been tested against a proposed method to show their suitability. Moreover, the quality of online clustering has been studied using standard clustering indices. Overall the framework provides a great opportunity for supporting emergency responders as demonstrated in real-world emergency exercises.}, address = {Amsterdam, Netherlands}, doi = {10.1016/j.neucom.2015.01.084}, language = {EN}, publisher = {Elsevier} } @InProceedings{Kreuzberger2015b, author = {Kreuzberger, Christian and Rainer, Benjamin and Hellwagner, Hermann}, booktitle = {IEEE International Conference on Multimedia Expo Workshops}, title = {Modelling the Impact of Caching and Popularity on Concurrent Adaptive Multimedia Streams in Information-Centric Networks}, year = {2015}, address = {Los Alamitos, CA, USA}, editor = {Matteo, Cesana}, month = {jul}, pages = {1--6}, publisher = {IEEE}, series = {ICMEW '15}, abstract = {The Internet is nowadays mainly used for streaming of multimedia content, something it was not built for originally. To guarantee user satisfaction, one of the key concepts of the Internet as we know it is bandwidth sharing. While this concept is necessary to provide stability in the network, several issues can arise with adaptive multimedia streaming, e.g., efficiency and stability. Considering Information-Centric Networking (ICN) and its network-inherent caching, those issues tend to become worse. Many researchers have proposed to use traffic shaping on the server to enable fair bandwidth sharing and stabilize clients. However, existing research does not consider content popularity and in-network caching. The contribution of this paper is two-fold. First, we propose a cache-aware traffic shaping policy, in order to guarantee seamless playback of videos. Second, based on content popularity, we calculate an average video quality achieved by this traffic shaping policy for various cache sizes, to show the impact of popularity and caching for multimedia streaming in ICN.}, doi = {10.1109/ICMEW.2015.7169763}, keywords = {Content Popularity; Adaptive Multimedia Streaming; Information-Centric Networking; Traffic Shaping}, language = {EN}, location = {Torino, Italy}, pdf = {https://www.itec.aau.at/bib/files/music_modelling_streaming_revision1_v3.pdf}, talkdate = {2015.07.03}, talktype = {registered} } @InProceedings{Kreuzberger2015a, author = {Kreuzberger, Christian and Posch, Daniel and Hellwagner, Hermann}, booktitle = {Proceedings of the 6th ACM Multimedia Systems Conference}, title = {A Scalable Video Coding Dataset and Toolchain for Dynamic Adaptive Streaming over HTTP}, year = {2015}, address = {New York, NY, USA}, editor = {Wei, Tsang Ooi}, month = {mar}, pages = {213--218}, publisher = {ACM}, series = {MMSys '15}, abstract = {With video streaming becoming more and more popular, the number of devices that are capable of streaming videos over the Internet is growing. This leads to a heterogeneous device landscape with varying demands. Dynamic Adaptive Streaming over HTTP (DASH) offers an elegant solution to these demands. Smart adaptation logics are able to adjust the clients' streaming quality according to several (local) parameters. Recent research indicated benefits of blending Scalable Video Coding (SVC) with DASH, especially considering Future Internet architectures. However, except for a DASH dataset with a single SVC encoded video, no other datasets are publicly available. The contribution of this paper is two-fold. First, a DASH/SVC dataset, containing multiple videos at varying bitrates and spatial resolutions including 1080p, is presented. Second, a toolchain for multiplexing SVC encoded videos is provided, therefore making our results reproducible and allowing researchers to generate their own datasets.}, doi = {10.1145/2713168.2713193}, isbn13 = {978-1-4503-3351-1}, keywords = {DASH; Dataset; Toolchain; Scalable Video Coding}, language = {EN}, location = {Portland, Oregon}, pdf = {https://www.itec.aau.at/bib/files/dash_svc_dataset_v1.05.pdf}, talkdate = {2015.03.18}, talktype = {registered}, url = {http://concert.itec.aau.at/SVCDataset/} } @InProceedings{HH2015a, author = {Hellwagner, Hermann and Kacianka, Severin}, booktitle = {MoVid '15 Proceedings of the 7th ACM International Workshop on Mobile Video}, title = {Adaptive Video Streaming for UAV Networks}, year = {2015}, address = {New York, USA}, editor = {Halvorsen, Pal and Dutt, Nikil}, month = {mar}, pages = {25-30}, publisher = {ACM International Conference on Multimedia Systems}, abstract = {The core problem for any adaptive video streaming solution, particularly over wireless networks, is the detection (or even prediction) of congestion. IEEE 802.11 is especially vulnerable to fast movement and change of antenna orientation. When used in UAV networks (Unmanned Aerial Vehicles), the network throughput can vary widely and is almost impossible to predict. this paper evaluates an approach originally developed by Kofler for home networks, in a single-hop UAV wireless network setting: the delay between the sending of an IEEE 802.11 packet and the receipt of its corresponding acknowledgement is used as an early indicator of the link quality and as a trigger to adapt (reduce or increase) the video stream' s bitrate. Our real-world flight-tests indicate, that this avoids congestion and can frequently avoid the complete loss of video pictures which happens without adaptation.}, doi = {10.1145/2727040.2727043}, isbn13 = {978-1-4503-3353-5}, keywords = {Video Streaming, Adaptive Streaming, UAVs, UAV Communication}, language = {EN}, location = {Portland, OR, USA}, talktype = {none} } @InProceedings{Bacher2015a, author = {Bacher, Florian and Rainer, Benjamin and Hellwagner, Hermann}, booktitle = {Proceedings of IEEE International Conference on Multimedia and Expo Workshops}, title = {Towards Controller-aided Multimedia Dissemination in Named Data Networking}, year = {2015}, address = {Los Alamitos, CA, USA}, editor = {not, available}, month = {jul}, pages = {1--6}, publisher = {IEEE}, series = {ICMEW '15}, abstract = {Software Defined Networking (SDN) and Named Data Networking (NDN) are two topics which have received lots of attention in the networking research community in recent years. While both have emerged independently from each other we believe that their core features can be well aligned to each other. Hence combining both may hold potential benefits for network operators. In this paper we investigate the advantage of having a central SDN controller which is aware of the complete topology of an underlying NDN network. In our approach we use the controller for routing Interests for names unknown to the forwarding elements and to find alternative routes in case of link congestion. Another advantage of SDN is the ability to analyze and control the network on an application-layer component which communicates with the controller. This allows the development of application-aware networks that support the specific needs of the applications that use them. As an example use case we assumed a network whose main purpose is to disseminate multimedia content with Zipf-distributed popularity among users. Having an application layer which knows about content popularity statistics we improve the dissemination of multimedia content by instructing dedicated nodes in the network to prefetch content which is expected to become popular in their geographical region or autonomous system (AS) in the near future. The aim of this approach is to reduce the distance to potential consumers and reduce the load of the core network.}, doi = {10.1109/ICMEW.2015.7169842}, isbn10 = {978­1­4799­7079­7}, keywords = {Information Centric Networking; Named Data Networking; Software Defined Networking; Routing; Forwarding; Caching}, language = {EN}, location = {Turino, Italy}, pdf = {https://www.itec.aau.at/bib/files/07169842.pdf}, talkdate = {2015.07.03}, talktype = {registered} } @Article{Timmerer2014_MMC, author = {Timmerer, Christian and Waltl, Markus and Rainer, Benjamin and Lederer, Stefan and Hellwagner, Hermann}, journal = {IEEE Multimedia Communications Technical Committee E-Letter}, title = {Enhancing 3D Video to enable a Fully Immersive Sensory Experiences}, year = {2014}, month = {jan}, number = {1}, pages = {23-26}, volume = {9}, address = {New York, NY, USA}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/E-Letter-Jan2014.pdf}, publisher = {IEEE Communications Society [online]}, url = {http://committees.comsoc.org/mmc/e-news/E-Letter-Jan2014.pdf} } @InProceedings{Raffelsberger2014, title = {Combined Mobile Ad-Hoc and Delay/Disruption-Tolerant Routing}, author = {Raffelsberger, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 13th International Conference on Ad-hoc, Mobile, and Wireless Networks (ADHOC-NOW '14)}, year = {2014}, address = {Berlin Heidelberg}, editor = {Guo, Song and Manzoni, Pietro and Lloret, Jaime and Ruehrup, Stefan}, month = {jun}, pages = {1-14}, publisher = {Springer}, series = {Lecture Notes in Computer Science (LNCS 8487)}, volume = {8487}, isbn13 = {978-3-319-07424-5}, keywords = {mobile ad-hoc networks; disruption-tolerant networks; routing; simulation}, language = {EN}, location = {Benidorm, Spain}, pdf = {https://www.itec.aau.at/bib/files/cr-adhocnow-authorver2.pdf}, talkdate = {2014.06.24}, talktype = {registered} } @InProceedings{Posch2014b, author = {Posch, Daniel and Kreuzberger, Christian and Rainer, Benjamin and Hellwagner, Hermann}, booktitle = {Proceedings of the 10th International Conference on Emerging Networking Experiments and Technologies, VideoNext Workshop}, title = {Using In-Network Adaptation to Tackle Inefficiencies Caused by DASH in Information-Centric Networks}, year = {2014}, address = {New York, NY, USA}, editor = {Dixon, Colin}, month = {dec}, pages = {1-6}, publisher = {ACM Digital Library}, abstract = {The consumption of audio-visual content is the most dominant traffic source in today's Internet. Novel architectural approaches, such as Information-Centric Networking (ICN), are developed to support efficient multimedia dissemination. As ICN and MPEG-DASH have several concepts in common, recent proposals consider a fusion of both technologies. However, MPEG-DASH relies on pure client-driven adaptation. This often rather selfish adaptation strategy inhibits benefits gained from ICN's inherent caching and multi-path transmission capabilities. In order to overcome this challenge, the contribution of this work is the integration of in-network adaptation (INA) in ICN. We illustrate that INA can be realized despite ICN's content-based security model. Our proposal rests on scalable content, which enables INA without management and transmission overhead.}, keywords = {Information-Centric Networking; In-Network Adaptation; Adaptive Streaming; Multimedia Dissemination}, language = {EN}, location = {Sydney, Australia}, pdf = {https://www.itec.aau.at/bib/files/video01fp.pdf}, talkdate = {2014.12.02}, talktype = {registered} } @InProceedings{Posch2014, author = {Posch, Daniel and Kreuzberger, Christian and Rainer, Benjamin and Hellwagner, Hermann}, booktitle = {Proceedings of the 1st ACM Conference on Information-Centric Networking}, title = {Client Starvation: A Shortcoming of Client-driven Adaptive Streaming in Named Data Networking}, year = {2014}, address = {New York, NY, USA}, editor = {Mendes, Paulo}, month = {sep}, pages = {1-2}, publisher = {ACM Digital Library}, abstract = {Information-centric Networking (ICN) as a potential Future Internet architecture has to efficiently support the consumption of multimedia content. Recent proposals consider the reuse of MPEG-DASH to provide adaptive streaming in ICN. Due to the fact that MPEG-DASH relies on pure client-driven adaptation, it encounters difficulties dealing with ICN's inherent caching and multi-path transmission. By conducting simulations using the concrete ICN approach Named Data Networking (NDN), we show that pure client-driven adaptation leads to shortcomings. Furthermore, we propose to use in-network adaptation based on scalable content for overcoming these shortcomings in NDN.}, doi = {10.1145/2660129.2660162}, keywords = {Information-centric Networking; Adaptive Streaming}, language = {EN}, location = {Paris, Frankreich}, pdf = {https://www.itec.aau.at/bib/files/icn14_final.pdf}, talkdate = {2014.09.26}, talktype = {poster}, url = {http://dx.doi.org/10.1145/2660129.2660162} } @Article{Pohl2014a, author = {Pohl, Daniela and Bouchachia,Abdelhamid and Hellwagner, Hermann}, journal = {E-Letter on Social Media Analysis for Crisis Management}, title = {Crisis-related Sub-Event Detection Based on Clustering}, year = {2014}, month = {mar}, note = {IEEE Computer Society Special Technical Community on Social Networking E-Letter}, number = {1}, pages = {1-10}, volume = {2}, address = {http://stcsn.ieee.net/e-letter/vol-2-no-1}, howpublished = {http://stcsn.ieee.net/e-letter/vol-2-no-1/crisis-related-sub-event-detection-based-on-clustering}, language = {EN}, publisher = {IEEE Computer Society Special Technical Community on Social Networking (STCSN)}, url = {http://stcsn.ieee.net/e-letter/vol-2-no-1/crisis-related-sub-event-detection-based-on-clustering} } @Article{Hellwagner2014c, author = {Lederer, Stefan and Mueller, Christopher and Timmerer, Christian and Hellwagner, Hermann}, journal = {IEEE Network}, title = {Adaptive Multimedia Streaming in Information-Centric Networks}, year = {2014}, month = {nov}, number = {6}, pages = {91-96}, volume = {28}, abstract = {ICN has received a lot of attention in recent years, and is a promising approach for the Future Internet design. As multimedia is the dominating traffic in today's and (most likely) the Future Internet, it is important to consider this type of data transmission in the context of ICN. In particular, the adaptive streaming of multimedia content is a promising approach for usage within ICN, as the client has full control over the streaming session and has the possibility to adapt the multimedia stream to its context (e.g. network conditions, device capabilities), which is compatible with the paradigms adopted by ICN. In this article we investigate the implementation of adaptive multimedia streaming within networks adopting the ICN approach. In particular, we present our approach based on the recently ratified ISO/IEC MPEG standard Dynamic Adaptive Streaming over HTTP and the ICN representative Content-Centric Networking, including baseline evaluations and open research challenges.}, address = {IEEE Communications Society}, language = {EN}, publisher = {IEEE} } @Article{Hellwagner2014b, author = {Andre, Torsten and Hummel, Karin Anna and Schoellig, Angela and Yanmaz, Evsen and Asadpour, Mahdi and Bettstetter, Christian and Grippa, Pasquale and Hellwagner, Hermann and Sand, Stephan and Zhang, Siwei}, journal = {IEEE Communications Magazine}, title = {Application-Driven Design of Aerial Communication Networks}, year = {2014}, month = {may}, number = {5}, pages = {129-137}, volume = {52}, abstract = {Networks of micro aerial vehicles (MAVs) equipped with various sensors are increasingly used for civil applications, such as monitoring, surveillance, and disaster management. In this article, we discuss the communication requirements raised by applications in MAV networks. We propose a novel system representation that can be used to specify different application demands. To this end, we extract key functionalities expected in an MAV network. We map these functionalities into building blocks to characterize the expected communication needs. Based on insights from our own and related real-world experiments, we discuss the capabilities of existing communications technologies and their limitations to implement the proposed building blocks. Our findings indicate that while certain requirements of MAV applications are met with available technologies, further research and development is needed to address the scalability, heterogeneity, safety, quality of service, and security aspects of multi-MAV systems.}, address = {IEEE Communications Society}, language = {EN}, publisher = {IEEE} } @Article{Hellwagner2014a, author = {Hellwagner, Hermann}, journal = {E-Letter on Social Media Analysis for Crisis Management}, title = {The BRIDGE Project - Bridging Resources and Agencies in Large-Scale Emergency Management}, year = {2014}, month = {mar}, note = {IEEE Computer Society Special Technical Community on Social Networking E-Letter}, number = {1}, pages = {1-10}, volume = {2}, abstract = {BRIDGE is a European collaborative project established within the Security Research sector of the European Commission. The basic goal of BRIDGE is to contribute to the safety of citizens by developing technical and organisational solutions that improve crisis and emergency management in EU member states. A (middleware) platform is being developed that is to provide technical support for multi-agency collaboration in large-scale emergency relief efforts. Several tools and software systems are being implemented and tested to support first responders in their efforts. Beyond technical considerations, organisational measures are being explored to ensure interoperability and cooperation among involved parties; social, ethical and legal issues are being investigated as well. A focus of the project is to demonstrate and validate its results in the course of real-world emergency response exercises. Since most of the BRIDGE work is beyond the scope of this e-letter on social networking, only a brief overview of the BRIDGE goals and work will be given. However, one thread of work is relevant in the context of social networking and deserves to be covered more closely: automatic detection of notable sub-events of a crisis from social networks. This activity makes use of crisis-related information coming from citizens via social networks and thus contributes to building an improved operational picture in a crisis situation and to better planning and performing crisis response tasks.}, address = {http://stcsn.ieee.net/e-letter/vol-2-no-1}, howpublished = {http://stcsn.ieee.net/e-letter/vol-2-no-1/the-bridge-project}, language = {EN}, publisher = {IEEE Computer Society Special Technical Community on Social Networking (STCSN)}, url = {http://stcsn.ieee.net/e-letter/vol-2-no-1/the-bridge-project} } @InCollection{hellwagner2013, author = {Hellwagner, Hermann}, booktitle = {Media and Convergence Management}, publisher = {Springer}, title = {The Interplay of Technology Development and Media Convergence: Examples}, year = {2013}, address = {Berlin, Heidelberg, New York}, editor = {Diehl, Sandra and Karmasin, Matthias}, month = {apr}, pages = {205-220}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/14_Hellwagner_Electronic_Version.pdf} } @Article{Waltl2012_MPEGVSI, author = {Waltl, Markus and Rainer, Benjamin and Timmerer, Christian and Hellwagner, Hermann}, journal = {Signal Processing: Image Communication}, title = {An End-to-End tool chain for sensory experience based on MPEG-V}, year = {2013}, month = {feb}, number = {2}, pages = {136--150}, volume = {28}, abstract = {This paper provides an overview of our research conducted in the area of Sensory Experience including our implementations using MPEG-V Part 3 entitled ”Sensory Information”. MPEG-V Part 3 introduces Sensory Experience as a tool to increase the Quality of Experience by annotating traditional multimedia data with sensory effects. These sensory effects are rendered on special devices like fans, vibration chairs, ambient lights, scent disposers, water sprayers, or heating/cooling devices stimulating senses beyond the traditional ones. The paper's main focus is on the end-to-end aspects including the generation, transmission, and synchronized rendering of sensory effects with the traditional multimedia data taking movie clips as an example. Therefore, we present in this paper an open source tool chain that provides a complete end-to-end sensory effect generation and consumption framework. Furthermore, we summarize results from various subjective quality assessments conducted in this area. Finally, we point out research challenges that may encourage further research within this emerging domain.}, address = {Amsterdam, Netherlands}, doi = {10.1016/j.image.2012.10.009}, keywords = {Quality of Experience; Sensory Experience; Subjective Quality Assessment; Experimental Results; MPEG-V; Annotation Tool; Simulation Tool; Web Browser Plug-in; Sensory Information}, language = {EN}, publisher = {Elsevier}, url = {http://dx.doi.org/10.1016/j.image.2012.10.009} } @Article{Szkaliczki2013, author = {Szkaliczki, Tibor and Eberhard, Michael and Hellwagner, Hermann and Szobonya, László}, journal = {Discrete Applied Mathematics}, title = {Piece selection algorithms for layered video streaming in P2P networks}, year = {2013}, month = {nov}, pages = {11}, address = {Amsterdam, The Netherlands}, language = {EN}, publisher = {Elsevier}, url = {http://dx.doi.org/10.1016/j.dam.2013.11.007} } @InProceedings{Raffelsberger2013a, author = {Raffelsberger, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the Eleventh IEEE International Conference on Pervasive Computing and Communications Workshops ({PerCom Workshops '13})}, title = {A Hybrid {MANET-DTN} Routing Scheme For Emergency Response Scenarios}, year = {2013}, address = {Los Alamitos, CA, USA}, editor = {Indulska, Jadwiga and Bisdikian, Chatschik}, month = {mar}, pages = {505-510}, publisher = {IEEE}, abstract = {Emergency response operations are a promising application area for mobile ad-hoc networks (MANETs). Most existing MANET routing protocols assume that an end-toend path between source and destination can be established. However, this assumption may not hold in a hastily formed network established during an emergency response. This paper evaluates a store-and-forward mechanism for proactive routing protocols to mitigate the effects of network disruptions. The mechanism is integrated into two routing protocols. The modified protocols are evaluated in an emergency response scenario that includes a disaster area mobility model and a wireless obstacle model. The scenario represents a realistic first responder operation after an incident in a chemical facility. The evaluation results show that networks for disaster responses benefit from the modified routing protocols.}, language = {EN}, location = {San Diego, CA, USA}, pdf = {https://www.itec.aau.at/bib/files/PerNEM2013-cr.pdf}, talkdate = {2013.03.22}, talktype = {registered} } @InProceedings{Raffelsberger2013, author = {Raffelsberger, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the Combined workshop on Self-organizing, Adaptive, and Context-Sensitive Distributed Systems and Self-organized Communication in Disaster Scenarios ({SACS/SoCoDiS} '13)}, title = {Overview of Hybrid {MANET-DTN} Networking and its Potential for Emergency Response Operations}, year = {2013}, address = {Berlin, Germany}, editor = {Zapf, Michael and Evers, Florian}, month = {mar}, pages = {1 -12}, publisher = {Electronic Communications of the EASST ({ECEASST})}, abstract = {Communication networks for emergency response operations have to operate in harsh environments. As fixed infrastructures may be unavailable (e.g., they are destroyed or overloaded), mobile ad-hoc networks (MANETs) are a promising solution to establish communication for emergency response operations. However, networks for emergency responses may provide diverse connectivity characteristics which imposes some challenges, especially on routing. Routing protocols need to take transmission errors, node failures and even the partitioning of the network into account. Thus, there is a need for routing algorithms that provide mechanisms from Delay or Disruption Tolerant Networking (DTN) in order to cope with network disruptions but at the same time are as efficient as MANET routing schemes in order to preserve network resources. This paper reviews several hybrid MANET-DTN routing schemes that can be found in the literature. Additionally, the paper evaluates a realistic emergency response scenario and shows that MANET-DTN routing schemes have the potential to improve network performance as the resulting network is diverse in terms of connectivity. In particular, the network provides well-connected regions whereas other parts are only intermittently connected.}, issn = {1863-2122}, language = {EN}, location = {Stuttgart, Germany}, pdf = {https://www.itec.aau.at/bib/files/SoCoDis2013-cr.pdf}, talkdate = {2013.03.15}, talktype = {registered} } @InProceedings{Posch2013, author = {Posch, Daniel and Hellwagner, Hermann and Schartner, Peter}, booktitle = {Proceedings of the 8th International Workshop on Secure Network Protocols (NPSec' 13)}, title = {On-Demand Video Streaming based on Dynamic Adaptive Encrypted Content Chunks}, year = {2013}, address = {Los Alamitos, CA, USA}, editor = {Li, Jun and Maennel, Olaf}, month = {oct}, pages = {6}, publisher = {IEEE}, abstract = {This paper proposes a framework for on-demand video streaming that enables secure and efficient delivery of data towards the end user. Our proposal requires the combined usage of three different technologies. The first one is a recent proposal by Jacobsen et al. called Content-Centric Networking (also known as Named Data Networking). It is a network architecture that introduces named data as the most valuable element in the network and divides it into so called content chunks, which are self-identifying and self-authenticating data units. The second concept we utilize derives from the approach of Dynamic Adaptive Streaming over HTTP, which allows clients to dynamically choose the quality of the received video stream according to their available resources. Finally, we adapt the concept of Broadcast Encryption to form a tool to control the access to provided content streams. The combination of these technologies enables us to design a framework that allows streaming providers to transport data to customers as dynamic adaptive encrypted content chunks, which is an efficient, flexible and scalable way of multimedia data transport.}, keywords = {Content-Centric Networking, CCN, Named Data Networking, NDN, Dynamic Adaptive Streaming, DASH, Broadcast Encryption, Video on Demand}, language = {EN}, location = {Germany, Göttingen}, pdf = {https://www.itec.aau.at/bib/files/ICNP_NPSEC_Streaming.pdf}, talkdate = {2013.10.07}, talktype = {registered} } @Article{Pohl2013d, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, journal = {Multimedia Tools and Applications}, title = {Social Media for Crisis Management: Clustering Approaches for Sub-Event Detection}, year = {2013}, month = {dec}, pages = {1-32}, address = {Springer, NY, US}, language = {EN}, publisher = {Springer US} } @Article{Pohl2013b, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, journal = {International Journal of Information Systems for Crisis Response and Management (IJISCRAM)}, title = {Supporting Crisis Management via Detection of Sub-Events in Social Networks}, year = {2013}, month = {jul}, number = {3}, pages = {20-36}, volume = {5}, address = {Hershey, PA, USA}, language = {EN}, publisher = {IGI Global} } @InProceedings{Pohl2013a, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, booktitle = {12th International Conference on Machine Learning and Applications}, title = {Online Processing of Social Media Data for Emergency Management}, year = {2013}, address = {Los Alamitos, CA, USA}, editor = {Tecuci, Gheorghe and Boicu, Mihai and Kubat, Miroslav}, month = {dec}, pages = {1-6}, publisher = {IEEE}, abstract = {Social media offers an opportunity for emergency management to identify issues that need immediate reaction. To support the effective use of social media, an analysis approach is needed to identify crisis-related hotspots. We consider in this investigation the analysis of social media (i.e., Twitter, Flickr and YouTube) to support emergency management by identifying sub-events. Sub-events are significant hotspots that are of importance for emergency management tasks. Aiming at sub-event detection, recognition and tracking, the data is processed online in real-time. We introduce an incremental feature selection mechanism to identify meaningful terms and use an online clustering algorithm to uncover sub-events on-the-fly. Initial experiments are based on tweets enriched with Flickr and YouTube data collected during Hurricane Sandy. They show the potential of the proposed approach to monitor sub-events for real-world emergency situations.}, keywords = {Online Clustering, Sub-Event Detection, Crisis Management}, language = {EN}, location = {Miami, Florida, USA}, pdf = {https://www.itec.aau.at/bib/files/Pohl_ICMLA13.pdf}, talkdate = {2013.12.01}, talktype = {poster} } @InProceedings{Mueller2013, author = {Mueller, Christopher and Lederer, Stefan and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {In Proceedings of the IEEE International Conference on Multimedia and Expo (ICME) 2013}, title = {Dynamic Adaptive Streaming over HTTP/2.0}, year = {2013}, address = {San Jose, USA}, editor = {Li, Jin}, month = {jul}, pages = {1-6}, publisher = {IEEE}, abstract = {MPEG Dynamic Adaptive Streaming over HTTP (DASH) is a new streaming standard that has been recently ratified as an international standard (IS). In comparison to other streaming systems, e.g., HTTP progressive download, DASH is able to handle varying bandwidth conditions providing smooth streaming. Furthermore, it enables NAT and Firewall traversal, flexible and scalable deployment as well as reduced infrastructure costs due to the reuse of existing Internet infrastructure components, e.g., proxies, caches, and Content Distribution Networks (CDN). Recently, the Hypertext Transfer Protocol Bis (httpbis) working group of the IETF has officially started the development of HTTP 2.0. Initially three major proposals have been submitted to the IETF i.e., Googles' SPDY, Microsofts' HTTP Speed+Mobility and Network-Friendly HTTP Upgrade, but SPDY has been chosen as working draft for HTTP 2.0. In this paper we implemented MPEG-DASH over HTTP 2.0 (i.e., SPDY), demonstrating its potential benefits and drawbacks. Moreover, several experimental evaluations have been performed that compare HTTP 2.0 with HTTP 1.1 and HTTP 1.0 in the context of DASH. In particular, the protocol overhead, the performance for different round trip times, and DASH with HTTP 2.0 in a lab test scenario has been evaluated in detail.}, language = {EN}, location = {San Jose, USA}, pdf = {https://www.itec.aau.at/bib/files/paper_330.pdf}, talkdate = {2013.07.17}, talktype = {registered} } @InProceedings{Liu2013, author = {Liu, Yaning and Geurts, Joost and Point, Jean-Charles and Lederer, Stefan and Rainer, Benjamin and Mueller, Christopher and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the IEEE international Conference on Communication (ICC) 2013 – Next-Generation Networking Symposium}, title = {Dynamic Adaptive Streaming over CCN: A Caching and Overhead Analysis}, year = {2013}, address = {Budapest}, editor = {Mattheisen, Christopher and Murase, Tutomu}, month = {jun}, pages = {2222-2226}, publisher = {IEEE}, abstract = {In this paper, we present our implementation and evaluation of Dynamic Adaptive Streaming over Content centric networking (DASC) which implements MPEG Dynamic Adaptive Streaming over HTTP (DASH) utilizing a Content Centric Networking (CCN) naming scheme to identify content segments in a CCN network. In particular, video segments formatted according to MPEG-DASH are available in different quality levels but instead of HTTP, CCN is used for referencing and delivery. Based on the conditions of the network, the DASC client issues interests for segments achieving the best throughput. Due to segment caching within the network, subsequent requests for the same content can be served quicker. As a result, the quality of the video a user receives progressively improves, effectively overcoming bottlenecks in the network. We present two sets of experiments to evaluate the performance of DASC showing that throughput indeed improves. However, the generated overhead is relatively large and the adaptation strategy used for DASH that assumes an end-to-end connection could be revised for the hop-by-hop architecture of CCN.}, keywords = {Content Centric Networking, Dynamic Adaptive Streaming, HTTP Video Streaming, MPEG-DASH}, language = {EN}, location = {Budapest, Hungary}, pdf = {https://www.itec.aau.at/bib/files/ICC2013 -DASH Over CCN.PDF}, talkdate = {2013.06.11}, talktype = {registered}, url = {http://www.ieee-icc.org} } @InProceedings{Lederer2013c, author = {Lederer, Stefan and Mueller, Christopher and Rainer, Benjamin and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the IEEE International Conference on Multimedia and Expo (ICME) 2013}, title = {An Experimental Analysis of Dynamic Adaptive Streaming over HTTP in Content Centric Networks}, year = {2013}, address = {San Jose, USA}, editor = {Wang, Haohong}, month = {jul}, pages = {1-6}, publisher = {IEEE}, abstract = {This paper presents the usage of CCN, which is a candidate for the next-generation Internet, in combination with the new Dynamic Adaptive Streaming over HTTP (DASH) standard, which was recently ratified by ISO/IEC MPEG. In contrast to the Internet Protocol, which is mainly based on the host-to-host connection paradigm originated in the 1970s, Content Centric Networking (CCN) focuses on the content itself, instead of its location. Considering the dominance of multimedia traffic in todays' Internet, the streaming performance of DASH over CCN as well as the problems introduced by this combination is worth to be investigated in detail. Therefore, we evaluate the protocol overhead introduced by the usage of CCN compared to the HTTP versions 1.0 and 1.1. Furthermore, the performance of DASH over CCN under different network conditions is compared to the performance of HTTP 1.0/1.1. Our results showed that although CCN comes together with higher protocol overhead than HTTP 1.0/1.1 as well as a prototype implementation, it can definitely compete with HTTP 1.0 in media streaming. Based on the evaluation results, problems as well as improvement possibilities are identified, which are the basis for future work in this area.}, language = {EN}, location = {San Jose, USA}, pdf = {https://www.itec.aau.at/bib/files/ICME_Overhead-Performance-DASHoverCCN.pdf}, talkdate = {2013.07.18}, talktype = {registered} } @InProceedings{Lederer2013b, author = {Lederer, Stefan and Mueller, Christopher and Rainer, Benjamin and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {In Proceedings of the IEEE ICC'13 - Workshop on Immersive \& Interactive Multimedia Communications over the Future Internet}, title = {Adaptive Streaming over Content Centric Networks in Mobile Networks using Multiple Links}, year = {2013}, address = {Budapest}, editor = {Assuncao, Pedro and Atzori, Luigi and Dagiuklas, Tasos and Kondoz, Ahmet}, month = {jun}, pages = {687-691}, publisher = {IEEE}, abstract = {This paper presents the usage of Content Centric Networking (CCN) for adaptive multimedia streaming in mobile environments, leveraging the recent ISO/IEC MPEG Dynamic Adaptive Streaming over HTTP (DASH) standard. The performance of DASH over CCN is evaluated using real-world mobile bandwidth traces and compared to previous evaluations of different DASH-based as well as proprietary systems. As there are no client-server connections in CCN, it offers the possibility to transfer data from multiple sources as well as over multiple links in parallel, which is definitely an important feature, e.g., for mobile devices offering multiple network links. This functionality is used and evaluated in this paper in combination with DASH, making it possible to dynamically choose the best performing link for media streaming, which is a clear advantage over DASH using HTTP and the TCP/IP protocol stack. The evaluation therefore investigates DASH over CCN in two scenarios using synthetic and real-world mobile bandwidth traces respectively, showing a significantly better performance than conventional DASH using only one connection.}, keywords = {MPEG-DASH, CCN, Dynamic Adaptive Streaming over HTTP, Content Centric Networking, Evaluation}, language = {EN}, location = {Budapest, Hungary}, pdf = {https://www.itec.aau.at/bib/files/ICC2013_Mobile_DASHoverCCN.pdf}, talkdate = {2013.06.13}, talktype = {registered}, url = {http://multicomm.diee.unica.it/} } @InProceedings{Grafl2013_ViDEv, author = {Grafl, Michael and Timmerer, Christian and Hellwagner, Hermann and Cherif, Wael and Ksentini, Adlen}, booktitle = {Proceedings of the 2nd {IEEE} {WoWMoM} Workshop on Video Everywhere ({ViDEv} 2013)}, title = {Evaluation of Hybrid Scalable Video Coding for {HTTP}-based Adaptive Media Streaming with High-Definition Content}, year = {2013}, address = {Los Alamitos, CA, USA}, editor = {Todd, Terence D and Paterakis, Michael}, month = {jun}, pages = {7}, publisher = {IEEE}, abstract = {Scalable Video Coding (SVC) in media streaming enables dynamic adaptation based on device capabilities and network conditions. In this paper, we investigate deployment options of SVC for Dynamic Adaptive Streaming over HTTP (DASH) with a special focus on scalability options, which are relevant for dynamic adaptation, especially in wireless and mobile environments. We evaluate the performance of SVC with respect to spatial and quality scalability options and compare it to non-scalable Advanced Video Coding (AVC). Performance evaluations are performed for various encoder implementations with high-definition (1080p) content. We show that a hybrid approach with multiple independent SVC bitstreams can have advantages in storage requirements at comparable rate-distortion performance.}, keywords = {scalable video coding; HTTP streaming; adaptation; high-definition; hybrid SVC-DASH}, language = {EN}, location = {Madrid, Spain}, pdf = {https://www.itec.aau.at/bib/files/Hybrid_SVC-DASH.pdf}, talkdate = {2013.06.04}, talktype = {registered} } @InProceedings{Grafl2013_ISCC, author = {Grafl, Michael and Timmerer, Christian and Hellwagner, Hermann and Cherif, Wael and Negru, Daniel and Battista, Stefano}, booktitle = {Proceedings of the 18th {IEEE} Symposium on Computers and Communication ({ISCC} 2013)}, title = {Scalable Video Coding Guidelines and Performance Evaluations for Adaptive Media Delivery of High Definition Content}, year = {2013}, address = {Los Alamitos, CA, USA}, editor = {Douligeris, Christos and Gotovac, Sven and Vojnović, Milan}, month = {jul}, pages = {6}, publisher = {IEEE}, abstract = {Scalability within media coding allows for content adaptation towards heterogeneous user contexts and enables in-network adaptation. However, there is no straightforward solution how to encode the content in a scalable way while maximizing rate-distortion performance. In this paper we provide encoding guidelines for scalable video coding based on a survey of media streaming industry solutions and a comprehensive performance evaluation using four state of the art scalable video codecs with a focus on high-definition content (1080p).}, keywords = {scalable video coding; adaptation; high-definition video; encoding; adaptive media streaming; content-aware networking}, language = {EN}, location = {Split, Coratia}, pdf = {https://www.itec.aau.at/bib/files/SVC_guide_and_eval.pdf}, talkdate = {2013.07.10}, talktype = {registered} } @Article{Grafl2013_ComCom, author = {Grafl, Michael and Timmerer, Christian and Hellwagner, Hermann and Cherif, Wael and Ksentini, Adlen}, journal = {Computer Communications}, title = {Hybrid Scalable Video Coding for {HTTP}-based Adaptive Media Streaming with High-Definition Content}, year = {2013}, issn = {01403664}, month = {dec}, pages = {11}, abstract = {Scalable Video Coding (SVC) in media streaming enables dynamic adaptation based on device capabilities and network conditions. In this paper, we investigate deployment options of SVC for Dynamic Adaptive Streaming over HTTP (DASH) with a special focus on scalability options, which are relevant for dynamic adaptation, especially in wireless and mobile environments. We establish encoding recommendations and evaluate the performance of SVC with respect to spatial and quality scalability options and compare it to non-scalable Advanced Video Coding (AVC). Performance evaluations are performed for various encoder implementations with high-definition (1080p) content. We show that a hybrid approach with multiple independent SVC bitstreams can have advantages in storage requirements at comparable rate-distortion performance.}, address = {Amsterdam, Netherlands}, language = {EN}, publisher = {Elsevier} } @Article{Grafl2012_MM, author = {Grafl, Michael and Timmerer, Christian and Hellwagner, Hermann and Xilouris, George and Gardikis, Georgios and Renzi, Daniele and Battista, Stefano and Borcoci, Eugen and Negru, Daniel}, journal = {IEEE MultiMedia}, title = {Scalable Media Coding enabling Content-Aware Networking}, year = {2013}, issn = {1070-986X}, month = {apr}, number = {2}, pages = {30-41}, volume = {20}, abstract = {Given that multimedia services are becoming increasingly popular, they are expected to play a dominant role for the Future Internet. In this context, it is essential that Content-Aware Networking (CAN) architectures, as envisaged in the frame of the Future Internet, explicitly address the efficient delivery and processing of multimedia content. This article proposes adopting a content-aware approach into the network infrastructure, thus making it capable of identifying, processing, and manipulating (i.e., adapting, caching, etc.) media streams and objects in real time towards Quality of Service/Experience (QoS/QoE) maximization. Our proposal is built upon the exploitation of scalable media coding technologies within such a content-aware networking environment and is discussed based on four representative use cases for media delivery (unicast, multicast, peer-to-peer, and adaptive HTTP streaming) and with respect to a selection of CAN challenges, specifically flow processing, caching/buffering, and QoS/QoE management.}, address = {Los Alamitos, CA, USA}, doi = {http://doi.ieeecomputersociety.org/10.1109/MMUL.2012.57}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/SMC_enabling_CAN.pdf}, publisher = {IEEE Computer Society} } @InCollection{Waltl2012_UserCentricraey, author = {Waltl, Markus and Raffelsberger, Christian and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {User Centric Media}, publisher = {Springer Verlag}, title = {Metadata-Based Content Management and Sharing System for Improved User Experience}, year = {2012}, address = {Berlin, Heidelberg, New York}, editor = {Alvarez, Federico and Costa, Cristina}, month = {dec}, pages = {132-140}, series = {Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering}, volume = {60}, doi = {10.1007/978-3-642-35145-7_17}, keywords = {Metadata; UPnP A/V; Content Management; Content Sharing; MPEG-V; Sensory Effects; User Experience}, language = {EN}, url = {http://dx.doi.org/10.1007/978-3-642-35145-7_17} } @InProceedings{Waltl2012_QoMEX2012_SensoryEffects, author = {Waltl, Markus and Timmerer, Christian and Rainer, Benjamin and Hellwagner, Hermann}, booktitle = {Proceedings of the 4th International Workshop on Quality of Multimedia Experience (QoMEX'12)}, title = {Sensory Effect Dataset and Test Setups}, year = {2012}, address = {Yarra Valley, Australia}, editor = {Burnett, Ian and Wu, Henry}, month = {jul}, pages = {115--120}, publisher = {IEEE}, abstract = {Additional constituents for the representation of multimedia content gained more and more attention. For example, the amount of cinemas equipped with additional devices (e.g., ambient light, vibrating seats, wind generators, water sprayers, heater/coolers) that stimulate senses going beyond audition and vision increases. On the content side the MPEG-V standard specifies – among others – Sensory Effect Metadata (SEM) which provides means to describe sensory effects such as wind, vibration, light, etc. to be attached to audio-visual content and, thus, offering an enhanced and immersive experience for the user. However, there is a lack of a common set of test content allowing for various subjective user studies and verification across different test sites. In this paper we provide our dataset comprising a number of videos from different genres enriched with MPEG-V compliant Sensory Effect Metadata descriptions. Furthermore, we describe possible test setups using off-the-shelf hardware for conducting subjective quality assessments.}, isbn13 = {-}, keywords = {Sensory Experience, Sensory Effects, MPEG-V, Dataset, Test Environment}, language = {EN}, location = {Yarra Valley, Australia}, pdf = {https://www.itec.aau.at/bib/files/QoMEX2012_Dataset.pdf}, talkdate = {2012.07.05}, talktype = {registered}, url = {http://www.qomex2012.org} } @Article{Waltl2012_MTAP, author = {Waltl, Markus and Timmerer, Christian and Rainer, Benjamin and Hellwagner, Hermann}, journal = {Multimedia Tools and Applications}, title = {Sensory Effects for Ambient Experiences in the World Wide Web}, year = {2012}, month = {may}, number = {-}, pages = {1--20}, volume = {-}, abstract = {More and more content in various formats becomes available via the WorldWideWeb (WWW). Currently availableWeb browsers are able to access and interpret these contents (i.e., Web videos, text, image, and audio). These contents stimulate only senses like audition or vision. Recently, it has been proposed to stimulate also other senses while consuming multimedia content, through so-called sensory effects. These sensory effects aim to enhance the ambient experience by providing effects such as light, wind, vibration, etc. The effects are represented as Sensory Effect Metadata (SEM) description which is associated to multimedia content and is rendered on devices like fans, vibration chairs, or lamps. In this paper we present two subjective quality assessments which comprise sensory effects, such as light, in the area of the WWW and their results achieved. The first assessment evaluates the influence of light effects on the Quality of Experience (QoE). The second assessment measures the impact of different settings for the color calculation on the viewing experience. Furthermore, we describe a Web browser plug-in for Mozilla Firefox which is able to render such sensory effects that are provided via the WWW.}, address = {Berlin, Heidelberg, New York}, doi = {10.1007/s11042-012-1099-8}, keywords = {World Wide Web, MPEG-V, Subjective quality assessment, Sensory effects, Quality of multimedia experience}, language = {EN}, publisher = {Springer Verlag}, url = {http://dx.doi.org/10.1007/s11042-012-1099-8} } @InProceedings{Waltl2012_MMM, author = {Waltl, Markus and Rainer, Benjamin and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Advances in Multimedia Modeling}, title = {Enhancing the User Experience with the Sensory Effect Media Player and AmbientLib}, year = {2012}, address = {Berlin, Heidelberg, New York}, editor = {Schoeffmann, Klaus and Merialdo, Bernard and Hauptmann, Alexander and Ngo, Chong-Wah and Andreopoulos, Yiannis and Breiteneder, Christian}, month = {jan}, pages = {624--626}, publisher = {Springer}, series = {LNCS 7131}, abstract = {Multimedia content is increasingly used in every area of our life. Still, each type of content only stimulates the visual and/or the hearing system. Thus, the user experience depends only on those two stimuli. In this paper we introduce a standard which offers the possibility to add additional effects to multimedia content. Furthermore, we present a multimedia player and a Web browser plug-in which uses this standard to stimulate further senses by using additional sensory effects (i.e., wind, vibration, and light) to enhance the user experience resulting in a unique, worthwhile sensory experience.}, keywords = {MPEG-V, User Experience, Sensory Experience, Media Player, Ambient, World Wide Web}, language = {EN}, location = {Klagenfurt, Austria}, pdf = {https://www.itec.aau.at/bib/files/mwbrcthh_mmm2012.pdf}, talkdate = {2012.01.05}, talktype = {poster} } @InProceedings{Waltl2012_ACMMM_OSSC, author = {Waltl, Markus and Rainer, Benjamin and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 20th ACM Multimedia (MM'12)}, title = {A Toolset for the Authoring, Simulation, and Rendering of Sensory Experiences}, year = {2012}, address = {Nara, Japan}, editor = {Babaguchi, Noboru and Aizawa, Kiyoharu and Smith, John}, month = {oct}, pages = {1469-1472}, publisher = {ACM}, abstract = {This paper describes a toolset for the authoring, simulating, and rendering of multimedia content annotated with Sensory Effect Metadata (SEM) descriptions as specified in Part 3 of the MPEG V standard. This part of MPEG-V standardizes the description of sensory effects (e.g., light, wind) in order to be rendered on sensory devices (e.g., fans, vibration chairs) aiming at generating a sensory experience stimulating possibly all human senses. Our implementation comprises a toolset to author sensory effects associated with multimedia content and the simulation thereof. Furthermore, it includes a library, a standalone player, and a Web browser plug-in which enables the playback and rendering of sensory effects on off-the-shelf rendering devices and in various contexts. All software modules are available under the GNU General Public License (GPL) v3 and the GNU Lesser General Public License (LGPL) v3 respectively.}, isbn13 = {-}, keywords = {MPEG-V, Annotation Tool, Simulator, Media Player, Web Browser Plug-in, Sensory Effects, Sensory Experience}, language = {EN}, location = {Nara, Japan}, pdf = {https://www.itec.aau.at/bib/files/acmmm2012_ossc_mwbrcthh.pdf}, talkdate = {2012.10.31}, talktype = {registered}, url = {http://www.acmm2012.org} } @Article{Timmerer2012909, author = {Timmerer, Christian and Waltl, Markus and Rainer, Benjamin and Hellwagner, Hermann}, journal = {Signal Processing: Image Communication}, title = {Assessing the quality of sensory experience for multimedia presentations}, year = {2012}, month = {sep}, number = {8}, pages = {909--916}, volume = {27}, abstract = {This paper introduces the concept of sensory experience by utilizing sensory effects such as wind or lighting as another dimension which contributes to the quality of the user experience. In particular, we utilize a representation format for sensory effects that are attached to traditional multimedia resources such as audio, video, and image contents. Sensory effects (e.g., wind, lighting, explosion, heat, cold) are rendered on special devices (e.g., fans, ambient lights, motion chair, air condition) in synchronization with the traditional multimedia resources and shall stimulate other senses than audition and vision (e.g., mechanoreception, equilibrioception, thermoreception), with the intention to increase the users Quality of Experience (QoE). In particular, the paper provides a comprehensive introduction into the concept of sensory experience, its assessment in terms of the QoE, and related standardization and implementation efforts. Finally, we will highlight open issues and research challenges including future work.}, address = {Amsterdam, Netherlands}, doi = {10.1016/j.image.2012.01.016}, keywords = {Quality of Experience, Sensory experience, Subjective quality assessment, Experimental results, MPEG-V}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/1-s2.0-S0923596512000252-main.pdf}, publisher = {Elsevier}, url = {http://dx.doi.org/10.1016/j.image.2012.01.016} } @InProceedings{Rainer2012_QoMEX2012_SensoryEffects, author = {Rainer, Benjamin and Waltl, Markus and Cheng, Eva and Shujau, Muawiyath and Timmerer, Christian and Davis, Stephen and Burnett, Ian and Hellwagner, Hermann}, booktitle = {Proceedings of the 4th International Workshop on Quality of Multimedia Experience (QoMEX'12)}, title = {Investigating the Impact of Sensory Effects on the Quality of Experience and Emotional Response in Web Videos}, year = {2012}, address = {Yarra Valley, Australia}, editor = {Burnett, Ian and Wu, Henry}, month = {jul}, pages = {278--283}, publisher = {IEEE}, abstract = {Multimedia is ubiquitously available online with large amounts of video increasingly consumed through Web sites such as YouTube or Google Video. However, online multimedia typically limits users to visual/auditory stimulus, with onscreen visual media accompanied by audio. The recent introduction of MPEG-V proposed multi-sensory user experiences in multimedia environments, such as enriching video content with so-called sensory effects like wind, vibration, light, etc. In MPEG-V, these sensory effects are represented as Sensory Effect Metadata (SEM), which is additionally associated to the multimedia content. This paper presents three user studies that utilize the sensory effects framework of MPEG-V, investigating the emotional response of users and enhancement of Quality of Experience (QoE) of Web video sequences from a range of genres with and without sensory effects. In particular, the user studies were conducted in Austria and Australia to investigate whether geography and cultural differences affect users’ elicited emotional responses and QoE.}, isbn13 = {-}, keywords = {Quality of Multimedia Experience, Sensory Effects, MPEG-V, Subjective Quality Assessment, World Wide Web, Sensory Experience}, language = {EN}, location = {Yarra Valley, Australia}, pdf = {https://www.itec.aau.at/bib/files/QoMEX2012_UserStudy.pdf}, talkdate = {2012.07.07}, talktype = {registered}, url = {http://www.qomex2012.org} } @InProceedings{Raffelsberger2012, author = {Raffelsberger, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the Tenth Workshop on Intelligent Solutions in Embedded Systems ({WISES '12})}, title = {Evaluation of MANET Routing Protocols in a Realistic Emergency Response Scenario}, year = {2012}, address = {Los Alamitos, CA, USA}, editor = {Quaritsch, Markus and Fehervari, Istvan}, month = {jul}, pages = {88-92}, publisher = {IEEE}, abstract = {We evaluate the performance of several routing protocols for mobile ad-hoc networks (MANETs) in an emergency response scenario. The simulated scenario uses a disaster area mobility model and a wireless shadowing model to represent realistic first responder movements in a hybrid indoor/outdoor environment. The resulting scenario imposes some challenges on the MANET routing protocols such as intermittent connectivity and network partitions. The simulation results show that nodes have diverse connectivity characteristics which are challenging for state-of-the-art MANET routing protocols.}, language = {EN}, location = {Klagenfurt, Austria}, pdf = {https://www.itec.aau.at/bib/files/WISES2012-cr.pdf}, talkdate = {2012.07.05}, talktype = {poster} } @InProceedings{Pohl2012c, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, booktitle = {11th International Conference on Machine Learning and Applications}, title = {Automatic Identification of Crisis-Related Sub-Events using Clustering}, year = {2012}, address = {Los Alamitos, CA, USA}, editor = {Han, Jiawei and Khoshgoftaar, Taghi M and Zhu, Xingquan}, month = {dec}, pages = {333-338}, publisher = {IEEE}, abstract = {Social media are becoming an important instrument for supporting crisis management, due to their broad acceptance and the intensive usage of mobile devices for accessing them. Social platforms facilitate collaboration among the public during a crisis and also support after-the-fact analysis. Thus, social media are useful for the processes of understanding, learning, and decision making. In particular, having information from social networks in a suitable, ideally summarized, form can speed up such processes. The present study relies on Flickr and YouTube as social media and aims at automatically identifying individual sub-events within a crisis situation. The study applies a two-phase clustering approach to detect those sub-events. The first phase uses geo-referenced data to locate a sub-event, while the second phase uses the natural language descriptions of pictures and videos to further identify the ”what-about” of those sub-events. The results show high potential of this social media-based clustering approach for detecting crisis-related sub-events.}, keywords = {Clustering, Sub-Event Detection, Crisis Management}, language = {EN}, location = {Boca Raton, Florida, USA}, pdf = {https://www.itec.aau.at/bib/files/06406815.pdf}, talkdate = {2012.12.12}, talktype = {registered}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6406815} } @InProceedings{Pohl2012b, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, booktitle = {IEEE 21st International Workshop on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE)}, title = {Supporting Crisis Management via Sub-Event Detection in Social Networks}, year = {2012}, address = {Toulouse, Fance}, editor = {Diaz, Michel and Senac, Patrick}, month = {jun}, pages = {373 -378}, publisher = {IEEE}, abstract = {Social networks give the opportunity to gather and share knowledge about a situation of relevance. This so called user-generated content is getting increasingly important during crisis management. It facilitates the collaboration with citizens or parties involved from the very beginning of the crisis. The information captured in form of images, text or videos is a valuable source of identifying sub-events of a crisis. In this study, we use metadata of images and videos collected from Flickr and YouTube to extract sub-events in crisis situations. We investigate the suitability of clustering techniques to detect sub-events. In particular two algorithms are evaluated on several data sets related to crisis situations. The results show the high potential of the approach proposed.}, doi = {10.1109/WETICE.2012.58}, issn = {1524-4547}, keywords = {Crisis Management, Information Retrieval, Clustering, Sub-Event Detection}, language = {EN}, location = {Toulouse, Fance}, talkdate = {2012.06.26}, talktype = {registered} } @InProceedings{Pohl2012a, author = {Pohl, Daniela and Bouchachia, Abdelhamid and Hellwagner, Hermann}, booktitle = {Proceedings of the 21st International Conference Companion on World Wide Web}, title = {Automatic Sub-Event Detection in Emergency Management using Social Media}, year = {2012}, address = {New York, NY, USA}, editor = {Mille, Alain and Gandon, Fabien and Misselis, Jacques}, month = {apr}, pages = {683--686}, publisher = {ACM}, series = {WWW '12 Companion}, abstract = {Emergency management is about assessing critical situations, followed by decision making as a key step. Clearly, information is crucial in this two-step process. The technology of social (multi)media turns out to be an interesting source for collecting information about an emergency situation. In particular, situational information can be captured in form of pictures, videos, or text messages. The present paper investigates the application of multimedia metadata to identify the set of sub-events related to an emergency situation. The used metadata is compiled from Flickr and YouTube during an emergency situation, where the identification of the events relies on clustering. Initial results presented in this paper show how social media data can be used to detect different sub-events in a critical situation.}, keywords = {Emergency Management, Social Media, Clustering}, language = {EN}, location = {Lyon, France}, pdf = {https://www.itec.aau.at/bib/files/p683.pdf}, talkdate = {2012.04.17}, talktype = {registered} } @InProceedings{Kuschnig2012a, author = {Kuschnig, Robert and Yanmaz, Evsen and Kofler, Ingo and Rinner, Bernhard and Hellwagner, Hermann}, booktitle = {Proceedings of the Austrian Robotics Workshop (ARW-12)}, title = {{Profiling IEEE 802.11 Performance on Linux-based UAVs}}, year = {2012}, address = {Graz, Austria}, editor = {Gerald Steinbauer, Suzana Uran}, month = {may}, pages = {6}, publisher = {Graz University of Technology}, language = {EN}, location = {Graz, Austria}, pdf = {https://www.itec.aau.at/bib/files/Kuschnig_ARW2012.pdf}, talktype = {none} } @InProceedings{Kofler2012, author = {Kofler, Ingo and Kuschnig, Robert and Hellwagner, Hermann}, booktitle = {Proceedings of the 9th {IEEE} Consumer Communications and Networking Conference ({CCNC})}, title = {Implications of the {ISO Base Media File Format} on Adaptive {HTTP} Streaming of {H.264/SVC}}, year = {2012}, address = {Los Alamitos, CA, USA}, editor = {Shirazi, Behrooz}, month = {jan}, pages = {5}, publisher = {IEEE}, abstract = {HTTP streaming has gained significant attraction in the last few years. Currently many commercial as well as standardized streaming systems are already offering adaptive streaming. In most cases, the adaptation is achieved by switching between separately encoded video streams in different qualities. In contrast to that, this paper focuses on the applicability of scalable video coding based on the H.264/SVC standard for adaptive HTTP streaming. Recent work has already highlighted the conceptual advantages like better cache utilization, fine-grained bit rate scalability, and lower storage requirements. This paper discusses the actual realization and design options for implementing priority streaming using the ISO~Base Media File Format (BMFF). We propose three different strategies for organizing the scalable video bit stream that consider both the possibilities as well as limitations of the ISO BMFF. The proposed strategies are discussed and evaluated both conceptually and quantitatively. For that purpose, we provide a detailed analysis based on modeling both the overhead of the file format and the HTTP encapsulation. The results for all three priority streaming strategies show that the limitations of the ISO BMFF result in a high relative overhead in the case of low bit rate content. However, when applied to high quality content, priority streaming of H.264/SVC can be implemented at a very low cost. Depending on the number of layers and the offered scalability dimensions, different strategies should be chosen to minimize the overhead. Based on the analytical model and the discussion, this paper provides guidance for selecting the most efficient strategy.}, language = {EN}, location = {Las Vegas, NV, USA}, pdf = {https://www.itec.aau.at/bib/files/Kofler_PriorityStreamingISOBMFF_preprint.pdf}, talkdate = {2012.01.14}, talktype = {registered}, url = {http://www.ieee-ccnc.org/2012/} } @InCollection{Hellwagner2012, author = {Hellwagner, Hermann}, booktitle = {Encyclopedia of Parallel Computing}, publisher = {Springer}, title = {Scalable Coherent Interface (SCI)}, year = {2012}, address = {Berlin, Heidelberg, New York}, editor = {Padua, David}, month = {jan}, pages = {9}, abstract = {Scalable Coherent Interface (SCI) is the specification (standardized by ISO/IEC and the IEEE) of a high-speed, flexible, scalable, point-to-point-based interconnect technology that was implemented in various ways to couple multiple processing nodes. SCI supports both the message-passing and shared-memory communication models, the latter in either the cache-coherent or non-coherent variants. SCI can be deployed as a system area network for compute clusters, as a memory interconnect for large-scale, cache-coherent, distributed-shared-memory multiprocessors, or as an I/O subsystem interconnect.}, language = {EN} } @InProceedings{Eberhard2012a, author = {Eberhard, Michael and Petrocco, Riccardo and Hellwagner, Hermann and Timmerer, Christian}, booktitle = {Proceedings of the Consumer Communication \& Networking Conference 2012}, title = {Comparison of Piece-Picking Algorithms for Layered Video Content in Peer-to-Peer Networks}, year = {2012}, address = {Los Alamitos, CA, U.S.A.}, editor = {Shirazi, Behrooz}, month = {jan}, pages = {1-5}, publisher = {IEEE}, language = {EN}, location = {Las Vegas, U.S.A.}, pdf = {https://www.itec.aau.at/bib/files/ccnc_pp_evaluation.pdf}, talkdate = {2012.01.15}, talktype = {registered} } @TechReport{Waltl2011_TR, author = {Waltl, Markus and Timmerer, Christian and Rainer, Benjamin and Hellwagner, Hermann}, institution = {Alpen-Adria-Universität Klagenfurt}, title = {Sensory Effects for Ambient Experiences in the World Wide Web}, year = {2011}, address = {Klagenfurt, Austria}, month = {jul}, number = {TR/ITEC/11/1.13}, abstract = {More and more content in various formats become available via the World Wide Web (WWW). Currently available Web browsers are able to access and interpret these contents (i.e., Web videos, text, image, and audio). These contents stimulate only senses like audition or vision. Recently, it has been proposed to stimulate also other senses while consuming multimedia content through so-called sensory effects. These sensory effects aim to enhance the ambient experience by providing effects, such as, light, wind, vibration, etc. The effects are represented as Sensory Effect Metadata (SEM) which is associated to multimedia content and is rendered on devices like fans, vibration chairs, or lamps. In this paper we present a plug-in for the Mozilla Firefox browser which is able to render such sensory effects that are provided via the WWW. Furthermore, the paper describes two user studies conducted with the plug-in and presents the results achieved.}, keywords = {World Wide Web, MPEG-V, Subjective Quality Assessment, Sensory Effects, Quality of Multimedia Experience}, language = {EN}, pages = {12}, pdf = {https://www.itec.aau.at/bib/files/Waltl_TR11113.pdf}, publisher = {Alpen-Adria Universität Klagenfurt} } @InProceedings{Waltl2011_MMWeb, author = {Waltl, Markus and Rainer, Benjamin and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop on Multimedia on the Web (MMWeb) 2011}, title = {Sensory Experience for Videos on the Web}, year = {2011}, address = {Los Alamitos, CA, USA}, editor = {Böszörmenyi, Laszlo and Marques, Oge and Lux, Mathias and Klamma, Ralf}, month = {sep}, pages = {1--3}, publisher = {IEEE}, abstract = {More and more multimedia content is becoming available via the World Wide Web (WWW). These contents stimulate only senses like hearing or vision. Recently, it has been proposed to stimulate also other senses while consuming multimedia content, through so-called sensory effects. These sensory effects aim at enhancing the user’s viewing experience by providing effects such as light, wind, vibration, etc. These effects are represented as Sensory Effect Metadata (SEM) which is associated to multimedia content and is rendered on devices like fans, lamps, or vibration chairs. In this paper, we present a plug-in for Web browsers which is able to render such sensory effects provided via Web content, and we describe a demonstrator that uses this plug-in to control an amBX system.}, keywords = {Quality of Experience, Sensory Experience, MPEG-V, Web Browser Plug-in, World Wide Web}, language = {EN}, location = {Graz, Austria}, pdf = {https://www.itec.aau.at/bib/files/MMWeb2011_mwbrcthh.pdf}, talkdate = {2011.09.08}, talktype = {poster} } @InProceedings{Szkaliczki2011, author = {Szkaliczki, Tibor and Eberhard, Michael and Hellwagner, Hermann and Szobonya, Laszlo}, booktitle = {7th Japanese-Hungarian Symposium on Discrete Mathematics and its Applications}, title = {Knapsack Problem and Piece Picking Algorithms for Layered Video Streaming}, year = {2011}, address = {Kyoto, Japan}, editor = {Fukunaga, Takuro and Iwata, Satoru and Nagamochi, Hiroshi and Takazawa, Kenjiro}, month = {may}, pages = {419-426}, publisher = {published on workshop homepage}, language = {EN}, location = {Kyoto, Japan}, pdf = {https://www.itec.aau.at/bib/files/hj2011_sztibor_final.pdf}, talkdate = {2011.05.31}, talktype = {registered} } @InProceedings{Quaritsch2011b, author = {Quaritsch, Markus and Kuschnig, Robert and Hellwagner, Hermann and Rinner, Bernhard}, booktitle = {Proceedings of the 8th International Conference on Information Systems for Crisis Response and Management (ISCRAM 2011)}, title = {Fast Aerial Image Acquisition and Mosaicking for Emergency Response Operations by Collaborative UAVs}, year = {2011}, address = {Berlin, Heidelberg, New York}, editor = {Dugdale,Julie and Mendonça,David}, month = {may}, pages = {5}, publisher = {Springer}, language = {EN}, location = {Lisbon, Portugal}, pdf = {https://www.itec.aau.at/bib/files/Quaritsch_ISCRAM2011.pdf}, talktype = {none} } @InProceedings{Quaritsch2011a, author = {Quaritsch, Markus and Kuschnig, Robert and Wischounig-Strucl, Daniel and Yahyanejad, Saeed and Mersheeva, Vera and Yanmaz, Evsen and Friedrich, Gerhard and Hellwagner, Hermann and Bettstetter, Christian and Rinner, Bernhard}, booktitle = {Proceedings of the Austrian Robotics Workshop (ARW-11)}, title = {FAMUOS: A Multi-UAV System for Aerial Reconnaissance in Rescue Scenarios}, year = {2011}, address = {Hall in Tyrol, Austria}, editor = {Hofbaur, Michael and Husty, Manfred}, month = {may}, pages = {3 3 3}, publisher = {UMIT}, language = {EN}, location = {Hall in Tyrol, Austria}, pdf = {https://www.itec.aau.at/bib/files/Quaritsch_ARW2011.pdf}, talktype = {none} } @InProceedings{Quaritsch2011, author = {Quaritsch, Markus and Wischounig-Strucl, Daniel and Yahyanejad, Saeed and Mersheeva, Vera and Yanmaz, Evsen and Friedrich, Gerhard and Hellwagner, Hermann and Bettstetter, Christian and Rinner, Bernhard}, booktitle = {Proceedings of the International Workshop on Self-Organizing Systems (IWSOS 2011)}, title = {Collaborative Microdrones Research Questions \& Challenges}, year = {2011}, address = {Berlin, Heidelberg, New York}, editor = {Zitterbart, Martina and de Meer, Hermann}, month = {jan}, pages = {38}, publisher = {Springer}, language = {EN}, talktype = {none} } @InProceedings{Kuschnig2011, author = {Kuschnig, Robert and Kofler, Ingo and Hellwagner, Hermann}, booktitle = {Proceedings of the Second Annual {ACM SIGMM} Conference on Multimedia Systems (MMSys)}, title = {Evaluation of {HTTP}-based request-response streams for internet video streaming}, year = {2011}, address = {New York, NY, USA}, editor = {Mayer-Patel, Ketan and Begen, Ali}, month = {feb}, pages = {245--256}, publisher = {ACM}, abstract = {Adaptive video streaming based on TCP/HTTP is becoming popular because of its ability to adapt to changing network conditions. We present an in-depth experimental analysis of the use of HTTP-based request-response streams for video streaming. In this scheme, video fragments are fetched by a client from the server, in smaller units called chunks, potentially via multiple parallel HTT P requests (TCP connections). A model for the achievable throughput is formulated.The model is validated by a broad range of streaming experiments, including an evaluation of TCP-friendliness. Our findings include that request-response streams are able to scale with the available bandwidth by increasing the chunk size or the number of concurrent streams. Several combinations of system parameters exhibiting TCP-friendliness are presented. We also evaluate the video streaming performance in terms of video quality in the presence of packet loss. Multiple request-response streams are able to maintain satisfactory performance, while a single TCP connection deteriorates rapidly with increasing packet loss. The results provide experimental evidence that HTTP-based request-response streams are a good alternative to classical TCP streaming}, doi = {10.1145/1943552.1943585}, language = {EN}, location = {San Jose, CA, USA}, pdf = {https://www.itec.aau.at/bib/files/mmsys11_kuschnig_preprint.pdf}, talkdate = {2011.02.25}, talktype = {registered} } @InProceedings{Kofler2011a, author = {Kofler, Ingo and Kuschnig, Robert and Hellwagner, Hermann}, booktitle = {Proceedings of the 2011 IEEE International Conference on Multimedia and Expo (ICME 2011)}, title = {Evaluating the Networking Performance of Home Router Platforms for Multimedia Services}, year = {2011}, address = {Los Alamitos, CA, USA}, editor = {Cheng, Irene and Fernandez, Gabriel and Wang, Haohong}, month = {jul}, pages = {6}, publisher = {IEEE}, series = {ICME}, abstract = {Wireless router platforms based on the Linux operating system are becoming popular in consumers' home networks. The transmission of multimedia data or their use as media-aware network elements imposes high traffic and computational loads on these devices. Thus, it is interesting to evaluate the networking and processing capabilities of such home router platforms in order to assess their usefulness for improved multimedia services such as in-network H.264/SVC video stream adaptation. This paper presents a performance evaluation of three home router platforms representative for low-end, mid-range, and high-end devices. The scope of the evaluation is the performance of the Linux networking stack on these routers; results for both application-layer (TCP and UDP) transmission and kernel-level (UDP) traffic routing are given. The results show that both TCP and UDP throughputs are significantly below (less than half of) the outgoing (wired) links' nominal capacities and depend very much on the sizes of the transmitted data blocks. This clearly indicates that the networking performance is limited by the platforms' processing capabilities and the lack of mechanisms that offload networking tasks from the CPUs. This behaviour cannot be observed on today's PC systems and has to be considered when deploying multimedia services on these network devices. Furthermore, a detailed analysis of the Linux networking stack reveals that the performance is heavily impacted by the netfilter code, even when no packet filtering or network address translation is being performed. Considerable performance gains can be achieved when this netfilter code is bypassed.}, doi = {10.1109/ICME.2011.6012189}, language = {EN}, location = {Barcelona, Spain}, pdf = {https://www.itec.aau.at/bib/files/platformeval_preprint.pdf}, talkdate = {2011.07.11}, talktype = {registered} } @InProceedings{Kofler2011, author = {Kofler, Ingo and Kuschnig, Robert and Hellwagner, Hermann}, booktitle = {Proceedings of the 21st International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 2011)}, title = {In-Network Adaptation of H.264/SVC for HD Video Streaming Over 802.11g Networks}, year = {2011}, address = {New York, NY, USA}, editor = {Krasic, Charles and Li, Kang}, month = {jun}, pages = {9-14}, publisher = {ACM}, series = {NOSSDAV}, abstract = {In this paper, we present an approach for in-network adaptation of H.264/SVC in the context of 802.11 wireless networks. It builds upon our previous work on an adaptive RTSP/RTP proxy which allows to adapt video streams on Linux-based home router platforms. The proposed approach tackles the throughput variations that occur as a consequence of the physical rate adaptation in 802.11 equipment caused by the mobility of clients. By combining monitoring information available exclusively on the wireless router with the ability to adapt scalable video streams on-the-fly, the proposed in-network adaptation approach allows to quickly adjust the video bit rate to the current link conditions. Instead of reacting on packet loss, our approach uses an increase in queueing delay at the router to detect phases of throughput degradation. This allows a higher responsiveness compared to traditional end-to-end approaches that rely solely on RTCP feedback. The behavior of our novel approach was evaluated in several mobility scenarios in an experimental test bed. The results obtained by streaming and adapting high-definition content clearly demonstrate the feasibility and benefits of this approach.}, doi = {10.1145/1989240.1989245}, language = {EN}, location = {Vancouver, Canada}, pdf = {https://www.itec.aau.at/bib/files/NOSSDAV2011_Preprint.pdf}, talkdate = {2011.06.02}, talktype = {registered} } @Article{Hellwagner2011a, author = {Hellwagner, Hermann and Hofbauer, Heinz and Kuschnig, Robert and Stütz, Thomas and Uhl, Andreas}, journal = {Journal on Signal Processing: Image Communication}, title = {Secure transport and adaptation of MC-EZBC video utilizing H.264-based transport protocols}, year = {2011}, issn = {0923-5965}, month = {nov}, pages = {30}, abstract = {Universal Multimedia Access (UMA) calls for solutions where content is created once and subsequently adapted to given requirements. With regard to UMA and scalability, which is required often due to a wide variety of end clients, the best suited codecs are wavelet based (like the MC-EZBC) due to their inherent high number of scaling options. However, most transport technologies for delivering videos to end clients are targeted toward the H.264/AVC standard or, if scalability is required, the H.264/SVC. In this paper we will introduce a mapping of the MC-EZBC bitstream to existing H.264/SVC based streaming and scaling protocols. This enables the use of highly scalable wavelet based codecs on the one hand and the utilization of already existing network technologies without accruing high implementation costs on the other hand. Furthermore, we will evaluate different scaling options in order to choose the best option for given requirements. Additionally, we will evaluate different encryption options based on transport and bitstream encryption for use cases where digital rights management is required.}, address = {Amsterdam, Netherlands}, doi = {10.1016/j.image.2011.11.002}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Elsevier_SPIC_Hellwagner11a.pdf}, publisher = {Elsevier B.V.} } @InCollection{Hellwagner2011, author = {Hellwagner, Hermann and Kofler, Ingo and Eberhard, Michael and Kuschnig, Robert and Ransburg, Michael and Sablatschan, Michael}, booktitle = {Streaming Media Architectures, Techniques and Applications: Recent Advances}, publisher = {Information Science Reference}, title = {Scalable Video Coding: Techniques and Applications for Adaptive Streaming}, year = {2011}, address = {Hershey, PA, USA}, editor = {Zhu, Ce and Li, Yuenan and Niu, Xiamu}, month = {jan}, pages = {1-23}, abstract = {This chapter covers the topic of making use of scalable video content in streaming frameworks and applications. Specifically, the recent standard H.264/SVC, i.e., the scalable extension of the widely used H.264/AVC coding scheme, and its deployment for adaptive streaming, the combined activities of content adaptation and streaming, are considered. H.264/SVC is regarded as a promising candidate to enable applications to cope with bandwidth variations in networks and heterogeneous usage environments, mainly diverse end device capabilities and constraints. The relevant coding and transport principles of H.264/SVC are reviewed first. Subsequently, an overview of H.264/SVC applications is given. The chapter then focuses on presenting architectural/implementation options and applications of H.264/SVC for adaptive streaming, emphasizing the aspect of where, i.e., on which network node and on which layer in the networking stack, in the video delivery path the content adaptation can take place; also, methods of content adaptation are covered. This pragmatic perspective is seen as complementing more general discussions of scalable video adaptation issues in the existing literature.}, doi = {10.4018/978-1-61692-831-5}, isbn10 = {161692831X}, isbn13 = {9781616928315}, language = {EN} } @InProceedings{Grafl2011_WoMAN, author = {Grafl, Michael and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 2011 IEEE International Conference on Multimedia and Expo (ICME 2011)}, title = {Quality Impact of Scalable Video Coding Tunneling for Media-Aware Content Delivery}, year = {2011}, address = {Los Alamitos, CA, USA}, editor = {Cheng, Irene and Fernandez, Gabriel and Wang, Haohong}, month = {jul}, pages = {4}, publisher = {IEEE}, series = {ICME}, abstract = {Today's omnipresent demand for access to multimedia content via diverse devices places new challenges on efficient content delivery. While the Scalable Video Coding (SVC) extension of Advanced Video Coding (AVC) has proven to be a useful tool for the advanced delivery of video content, it has not yet found major adoption in practice. This paper introduces the concept of SVC tunneling developed in the EU FP7 ALICANTE project, which attempts to provide device-independent access to media resources at reduced network load. For SVC tunneling, video transcoding is performed at the ingress/egress points of the network, which may impact the video quality. We show that the quality impact of these transcoding steps for a transcoding chain from MPEG-2 to SVC and back to MPEG-2 accumulates to a PSNR reduction of up to 2.1 dB for transcoding at fixed target bitrates. We also discuss research challenges and open issues in SVC tunneling.}, doi = {10.1109/ICME.2011.6012239}, keywords = {Content-aware networking; scalable video coding; quality of service; SVC tunneling; transcoding; multimedia distribution}, language = {EN}, location = {Barcelona, Spain}, pdf = {https://www.itec.aau.at/bib/files/WoMAN2011_paper_209.pdf}, talkdate = {2011.07.11}, talktype = {registered} } @InCollection{Grafl2011_TI, author = {Grafl, Michael and Timmerer, Christian and Hellwagner, Hermann and Negru, Daniel and Borcoci, Eugen and Renzi, Daniele and Mevel, Anne-Lore and Chernilov, Alex}, booktitle = {Trustworthy Internet}, publisher = {Springer}, title = {Scalable Video Coding in Content-Aware Networks: Research Challenges and Open Issues}, year = {2011}, address = {Berlin, Heidelberg, New York}, editor = {Blefari-Melazzi, Nicola and Bianchi, Giuseppe and Salgarelli, Luca}, month = {jun}, pages = {11}, abstract = {The term “trustworthy” has a very precise connotation in the European Community’s FP7 research program. For a network to be qualified as trustworthy, it needs to be secure, reliable and resilient to attacks and operational failures. Furthermore, quality of service must be guaranteed, while protecting user data, ensuring privacy and providing usable and trusted tools to support users in their security management. As such, the Trustworthy Internet not only has to include mechanisms, architectures and networking infrastructures that intrinsically provide basic security guarantees, but it also has to ensure users, service providers and application providers alike that their requirements in terms of Quality of Experience, manageability and efficiency are fully met. Providing such combined guarantees in a rapidly evolving, complex infrastructure such as the Internet requires solving challenging issues that encompass many fields of theoretical and applied information engineering. These issues span all levels of the protocol stack, ranging from finding new intrinsically secure transmission systems, to radically novel routing models, to new architectures for data dissemination and for interconnecting an unprecedented number of devices and appliances. This book aims at representing a view of the state of the “Trustworthy Internet” as we enter the second decade of our century. The material included in this book originated from the 21st International Tyrrhenian Workshop on Digital Communications, an event traditionally organized by CNIT, the Italian inter-university consortium for telecommunication research. The workshop comprised either invited contributions from renowned researchers with complementary expertise, as well as independent, peer-reviewed contributions stimulated through an open call for papers. This volume includes a selected subset of the workshop papers. Each contribution has been edited and extended after the workshop, taking into account the discussions carried out during the event, incorporating when appropriate additional technical material. Furthermore, the authors have strived to complement the specific technical aspects they present with background material devised to more comprehensively introduce the reader to the specific topic of trustworthiness tackled.}, doi = {10.1007/978-88-470-1818-1_26}, isbn10 = {884701817X}, isbn13 = {978-8847018174}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/SVC4CAN_chapter_v1.0.pdf} } @InProceedings{Eberhard2011b, author = {Eberhard, Michael and Hellwagner, Hermann and Timmerer, Christian and Szkaliczki, Tibor and Szobonya, Laszlo}, booktitle = {Proceedings of the 2011 {IEEE} International Conference on Multimedia and Expo (ICME 2011)}, title = {An evaluation of piece-picking algorithms for layered content in Bittorrent-based peer-to-peer systems}, year = {2011}, address = {Los Alamitos, CA, USA}, editor = {Cheng, Irene and Fernandez, Gabriel and Wang, Haohong}, month = {jul}, pages = {1-6}, publisher = {IEEE}, series = {ICME}, language = {EN}, location = {Barcelona, Spain}, pdf = {https://www.itec.aau.at/bib/files/icme2011_piece-picking.pdf}, talkdate = {2011.07.11}, talktype = {registered} } @InCollection{hellwagner2010, author = {Hellwagner, Hermann and Timmerer, Christian}, booktitle = {The Handbook of MPEG Applications: Standards in Practice}, publisher = {John Wiley \& Sons}, title = {MPEG-21 Applications and Use Cases}, year = {2010}, address = {Hoboken, New Jersey}, editor = {Angelides, Marios C and Agius, Harry}, month = {nov}, pages = {405-430}, abstract = {This book provides a comprehensive examination of the use of MPEG-2, MPEG-4, MPEG-7, MPEG-21, and MPEG-A standards, providing a detailed reference to their application. In this book, the authors address five leading MPEG standards, focusing not only on the standards themselves, but specifically upon their application (e.g. for broadcasting media, personalised advertising and news, multimedia collaboration, digital rights management, resource adaptation, digital home systems, and so on); including MPEG cross-breed applications. In the evolving digital multimedia landscape, this book provides comprehensive coverage of the key MPEG standards used for generation and storage, distribution and dissemination, and delivery of multimedia data to various platforms within a wide variety of application domains. It considers how these MPEG standards may be used, the context of their use, and how supporting and complementary technologies and the standards interact and add value to each other. Key Features: * Integrates the application of five popular MPEG standards (MPEG-2, MPEG-4, MPEG-7, MPEG-21, and MPEG-A) into one single volume, including MPEG cross-breed applications * Up-to-date coverage of the field based on the latest versions of the five MPEG standards * Opening chapter provides overviews of each of the five MPEG standards * Contributions from leading MPEG experts worldwide * Includes an accompanying website with supporting material (www.wiley.com/go/angelides_mpeg) This book provides an invaluable reference for researchers, practitioners, CTOs, design engineers, and developers. Postgraduate students taking MSc, MRes, MPhil and PhD courses in computer science and engineering, IT consultants, and system developers in the telecoms, broadcasting and publishing sectors will also find this book of interest.}, isbn10 = {0470750073}, isbn13 = {978-0470750070}, language = {EN} } @InProceedings{Waltl2010_WIAMIS_SensoryEffects, author = {Waltl, Markus and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 11th International Workshop on Image Analysis for Multimedia Interactive Services (WIAMIS'10)}, title = {Increasing the User Experience of Multimedia Presentations with Sensory Effects}, year = {2010}, address = {Los Alamitos, CA, USA}, editor = {Leonardi, Riccardo and Migliorati, Pierangelo and Cavallaro, Andrea}, month = {apr}, pages = {1-4}, publisher = {IEEE}, abstract = {The term Universal Multimedia Experience (UME) has gained momentum and is well recognized within the research community. As this approach puts the user into the center stage, additional complexity is added to the overall quality assessment problem which calls for a scientific framework to capture, measure, quantify, judge, and explain the user experience. In previous work we have proposed the annotation of multimedia content with sensory effect metadata that can be used to stimulate also other senses than vision or audition. In this paper we report first results obtained from subjective tests in the area of sensory effects attached to traditional multimedia presentations such as movies that shall lead to an enhanced, unique, and worthwhile user experience.}, isbn13 = {9781424478484}, keywords = {Sensory Information, MPEG-V}, language = {EN}, location = {Desenzano del Garda, Italy}, pdf = {https://www.itec.aau.at/bib/files/wiamis2010_mwcthh.pdf}, talkdate = {2010.04.13}, talktype = {poster} } @InProceedings{Waltl2010_QoMEX2010_SensoryEffects, author = {Waltl, Markus and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 2nd International Workshop on Quality of Multimedia Experience (QoMEX'10)}, title = {Improving the Quality of Multimedia Experience through Sensory Effects}, year = {2010}, address = {Los Alamitos, CA, USA}, editor = {Perkis, Andrew and Möller, Sebastian and Svensson, Peter and Reibman, Amy}, month = {jun}, pages = {124-129}, publisher = {IEEE}, abstract = {In previous and related work sensory effects are presented as a tool for increasing the user experience of multimedia presentations by stimulating also other senses than vision or audition. In this paper we primarily investigated the relationship of the Quality of Experience (QoE) due to various video bit-rates of multimedia contents annotated with sensory effects (e.g., wind, vibration, light). Therefore, we defined a subjective quality assessment methodology based on standardized methods. The paper describes the test environment, its setup, and conditions in detail. Furthermore, we experimented with a novel voting device that allows for continuous voting feedback during a sequence in addition to the overall quality voting at the end of each sequence. The results obtained from the subjective quality assessment are presented and discussed thoroughly. In anticipation of the results we can report an improvement of the quality of the multimedia experience thanks to the sensory effects.}, doi = {10.1109/QOMEX.2009.5246962}, isbn13 = {9781424469581}, keywords = {Sensory Information, MPEG-V}, language = {EN}, location = {Trondheim, Norway}, pdf = {https://www.itec.aau.at/bib/files/qomex2010_mwcthh.pdf}, talkdate = {2010.06.21}, talktype = {poster}, url = {http://www.qomex2010.org} } @InProceedings{Waltl2010_IMOF2010_SensoryEffects, author = {Waltl, Markus and Raffelsberger, Christian and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings CD of the 2nd International ICST Conference on User Centric Future Media Internet}, title = {Metadata-based Content Management and Sharing System for Improved User Experience}, year = {2010}, address = {Berlin, Heidelberg, New York}, editor = {Alvarez, Federico and Costa, Cristina}, month = {sep}, pages = {1-9}, publisher = {Springer Verlag GmbH}, abstract = {In the past years the amount of multimedia content on the Internet or in home networks has been drastically increasing. Instead of buying traditional media (such as CDs or DVDs) users tend to buy online media. This leads to the difficulty of managing the content (e.g., movies, images). A vast amount of tools for content management exists but they are mainly focusing on one type of content (e.g., only images). Furthermore, most of the available tools are not configurable to the user’s preferences and cannot be accessed by different devices (e.g., TV, computer, mobile phone) in the home network. In this paper we present a UPnP A/V-based system for managing and sharing audio/visual content in home environments which is configurable to the user’s preferences. Furthermore, the paper depicts how this system can be used to improve the user experience by using MPEG-V.}, isbn13 = {9789639995000}, keywords = {Sensory Information, MPEG-V}, language = {EN}, location = {Palma de Mallorca, Spain}, pdf = {https://www.itec.aau.at/bib/files/ucmedia2010_mwcrcthh.pdf}, talkdate = {2010.09.01}, talktype = {registered} } @InProceedings{Timmerer2010_WISMA_SensoryEffects, author = {Timmerer, Christian and Waltl, Markus and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop on Interoperable Social Multimedia Applications (WISMA 2010)}, title = {Are Sensory Effects Ready for the World Wide Web?}, year = {2010}, address = {Aachen, Germany}, editor = {Carreras, Anna and Delgado, Jaime and Maroñas, Xavier and Rodríguez, Víctor}, month = {may}, pages = {57-60}, publisher = {CEUR Workshop Proceedings (CEUR-WS.org)}, abstract = {The World Wide Web (WWW) is one of the main entry points to access and consume Internet content in various forms. In particular, the Web browser is used to access different types of media (i.e., text, image, audio, and video) and on some platforms is the only way to access the vast amount of information on the Web. Recently, it has been proposed to stimulate also other senses than vision or audition while consuming multimedia content through so- called sensory effects, with the aim to increase the user’s Quality of Experience (QoE). The effects are represented as Sensory Effects Metadata (SEM) which is associated to traditional multimedia content and is rendered (synchronized with the media) on sensory devices like fans, vibration chairs, lamps, etc. In this paper we provide a principal investigation of whether the sensory effects are ready for the WWW and, in anticipation of the result, we propose how to embed sensory effect metadata within Web content and the synchronized rendering thereof.}, keywords = {MPEG-V}, language = {EN}, location = {Barcelona, Spain}, pdf = {https://www.itec.aau.at/bib/files/MPEG-V_v2.1.pdf}, talkdate = {2010.05.19}, talktype = {registered} } @InProceedings{Timmerer2010_WISMA_Metadata, author = {Timmerer, Christian and Eberhard, Michael and Grafl, Michael and Mitchell, Keith and Dutton, Sam and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop on Interoperable Social Multimedia Applications (WISMA 2010)}, title = {A Metadata Model for Peer-to-Peer Media Distribution}, year = {2010}, address = {Aachen, Germany}, editor = {Carreras, Anna and Delgado, Jaime and Maroñas, Xavier and Rodríguez, Víctor}, month = {may}, pages = {8}, publisher = {CEUR Workshop Proceedings (CEUR-WS.org)}, abstract = {In this paper we describe a metadata solution for a Peer-to-Peer (P2P) content distribution system termed NextShare. We outline the key motivating factors for our approach, detail the overall generic architecture we have developed and present the workflow for delivering metadata through Peer-to-Peer based content distribution. The paper also presents the metadata model we have developed and we describe in detail how all the content can be packetized and distributed using NextShare. Finally, a description of the core and optional metadata attributes which may be utilized within the system is provided.}, keywords = {Metadata, peer-to-peer streaming, social networks, payment and cashing, advertisements, MPEG-21 Digital Item, API.}, language = {EN}, location = {Barcelona, Spain}, pdf = {https://www.itec.aau.at/bib/files/P2P-Metadata_v2.0.pdf}, talkdate = {2010.05.19}, talktype = {registered}, url = {http://www.multimedia-metadata.info/Members/ralf/callforpapers.2010-02-01.6353762208} } @InProceedings{Timmerer2010_ITWDC, author = {Timmerer, Christian and Grafl, Michael and Hellwagner, Hermann and Negru, Daniel and Borcoci, Eugen and Renzi, Daniel and Mevel, Anne-Lore and Chernilov, Alex}, booktitle = {Proceedings of the International Tyrrhenian Workshop on Digital Communications (ITWDC)}, title = {Scalable Video Coding in Content-Aware Networks: Research Challenges and Open Issues}, year = {2010}, address = {New York, NY, USA}, editor = {Blefari-Melazzi, Nicola}, month = {sep}, pages = {11}, publisher = {Springer}, abstract = {The demand for access to advanced, distributed media resources is nowadays omnipresent due to the availability of Internet connectivity almost anywhere, anytime, and with a huge amount of different devices. This calls for rethinking of the current Internet architecture by making the network aware of which content is actually transported. This paper introduces Scalable Video Coding (SVC) as a tool for Content-Aware Networks (CANs) which is currently researched as part of the EU FP7 ALICANTE project. The architecture of ALICANTE with respect to SVC and CAN is reviewed, use cases are described, and, finally, research challenges and open issues are discussed.}, language = {EN}, location = {Island of Ponza, Italy}, pdf = {https://www.itec.aau.at/bib/files/SVC4CAN_v1.0.pdf}, talkdate = {2010.09.08}, talktype = {registered} } @InProceedings{Timmerer2010_INTL-DPIF, author = {Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the 1st International Digital Preservation Interoperability Framework Symposium}, title = {MPEG-21 digital items in research and practice}, year = {2010}, address = {New York, NY, USA}, editor = {Chang, Wo}, month = {apr}, pages = {8:1-8:8}, publisher = {ACM}, series = {INTL-DPIF}, abstract = {The aim of the MPEG‐21 standard, the so‐called Multimedia Framework, is to enable transparent and augmented use of multimedia resources across a wide range of networks, devices, user preferences, and communities, notably for trading (of bits). As such, it provides an important step in MPEG's standards evolution, i.e., the transaction of Digital Items among Users. This paper provides an overview of applications making use specifically of MPEG‐21 Digital Items and a more in‐depth presentation of a few selected applications in research and practice.}, doi = {10.1145/2039263.2039271}, keywords = {DANAE, ENTHRONE, MPEG-21, P2P-Next, UPnP, application, digital item, digital library, usage}, language = {EN}, location = {Dresden, Germany}, pdf = {https://www.itec.aau.at/bib/files/a8-timmerer.pdf}, slides = {https://www.itec.aau.at/bib/files/DPIF2010_v1.0.pdf}, talkdate = {2010.04.22}, talktype = {registered} } @Article{Timmerer2010_DeliveryContextDescriptionFormats, author = {Timmerer, Christian and Jaborning, Johannes and Hellwagner, Hermann}, journal = {Journal of Digital Information Management}, title = {A Survey on Delivery Context Description Formats - A Comparison and Mapping Model}, year = {2010}, month = {feb}, number = {1}, pages = {16-27}, volume = {8}, abstract = {Nowadays, mobile devices have implemented several transmission technologies which enable access to the Internet and increase the bit rate for data exchange. Despite modern mobile processors and high-resolution displays, mobile devices will never reach the stage of a powerful notebook or desktop system (for example, due to the fact of battery powered CPUs or just concerning the small-sized displays). Due to these limitations, the deliverable content for these devices should be adapted based on their capabilities including a variety of aspects (e.g., from terminal to network characteristics). These capabilities should be described in an interoperable way. In practice, however, there are many standards available and a common mapping model between these standards is not in place. Therefore, in this paper we describe such a mapping model and its implementation aspects. In particular, we focus on the whole delivery context (i.e., terminal capabilities, net- work characteristics, user preferences, etc.) and investigated the two most prominent state-of-the-art description schemes, namely User Agent Profile (UAProf) and Usage Environment Description (UED).}, address = {Chennai, India}, keywords = {CC/PP, DCO, Delivery Context, Metadata, UAProf, UED}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A Survey on Delivery Context Description Formats – A Comparison and Mapping Model.pdf}, publisher = {Digital Information Research Foundation} } @Article{Szkaliczki2010, author = {Szkaliczki, Tibor and Eberhard, Michael and Hellwagner, Hermann and Szobonya, László}, journal = {Electronic Notes in Discrete Mathematics}, title = {Piece Selection Algorithm for Layered Video Streaming in P2P Networks}, year = {2010}, issn = {1571-0653}, month = {aug}, note = {ISCO 2010 - International Symposium on Combinatorial Optimization}, pages = {1265-1272}, volume = {36}, abstract = {This paper introduces the piece selection problem that arises when streaming layered video content over peer-to-peer networks. The piece selection algorithm decides periodically which pieces to request from other peers (network nodes) for download. The main goal of the piece selection algorithm is to provide the best possible quality for the available bandwidth. Our recommended solution approaches are related to the typical problems and solutions in the knapsack problem.}, address = {New York, USA}, doi = {10.1016/j.endm.2010.05.160}, keywords = {streaming, layered video, knapsack problem}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/ISCO'10_Eberhard.pdf}, publisher = {Elsevier Inc.}, url = {http://www.sciencedirect.com/science/article/B75GV-50JJF7F-5P/2/7d978923400f50d4c42165003c64c351} } @InProceedings{Sablatschan2010a, author = {Sablatschan, Michael and Ortiz Murillo, Jordi and Ransburg, Michael and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop SVCVision, in conjunction with the 6th International Mobile Multimedia Communications Conference (MobiMedia 2010)}, title = {Efficient SVC-to-AVC Conversion at a Media Aware Network Element}, year = {2010}, address = {Berlin, Heidelberg, New York}, editor = {Rodriguez, Jonathan and Tafazolli, Rahim and Verikoukis, Christos}, month = {sep}, pages = {7}, publisher = {Springer}, abstract = {H.264/SVC, the Scalable Video Coding extension of the H.264/AVC video coding standard, features spatial, quality and temporal scalability. Backwards compatibility with legacy decoding devices is maintained through an H.264/AVC compliant base layer, which represents the lowest quality of an H.264/SVC bit-stream. However, it is often desireable to also provide the higher quality layers to legacy H.264/AVC devices. This is achieved by a process commonly known as "bit-stream rewriting", which allows for an efficient H.264/SVC to H.264/AVC conversion by exploiting the similarities of the two codecs. This paper describes a demonstrator showing the advantages of including an improved version of the bit-stream rewriting tool from the existing JSVM H.264/SVC reference software in an H.264/SVC-based multimedia delivery system, by integrating it into a Media Aware Network Element.}, keywords = {Multimedia Adaptation, H.264/SVC, SVC-to-AVC rewriting}, language = {EN}, talktype = {none} } @InProceedings{Sablatschan2010, author = {Sablatschan, Michael and Ransburg, Michael and Hellwagner, Hermann}, booktitle = {Proceedings of the Second International Conferences on Advances in Multimedia (MMEDIA 2010)}, title = {Towards an Improved SVC-to-AVC Rewriter}, year = {2010}, address = {Los Alamitos, CA, USA}, editor = {Böszörmenyi, Laszlo and Burdescu, Dumitru and Davis, Philip and Stanchev, Peter}, month = {jun}, pages = {18-21}, publisher = {IEEE}, abstract = {The Scalable Video Coding (SVC) extension of the H.264/AVC (AVC) video coding standard features spatial, quality and temporal scalability. Backwards compatibility with legacy decoding devices is maintained through an H.264/AVC compliant base layer, which represents the lowest quality of an SVC bit-stream. However, it is often desirable to also provide the higher quality layers to legacy H.264/AVC devices. This is achieved by a process commonly known as “bit-stream rewriting”, which allows for an efficient SVC to AVC conversion by exploiting the similarities of the two codecs. This paper introduces an improved version of the existing JSVM reference software rewriter (JSVM-rewriter). The improvements include a better run-time performance through parallel processing, as well as applicability in streaming scenarios. A detailed evaluation provides performance measurements for the improved rewriter and compares it to the existing JSVM-rewriter. The evaluation shows that notable performance improvements can be achieved using the presented approach. The paper concludes on how the rewriter could be further improved.}, doi = {10.1109/MMEDIA.2010.27}, language = {EN}, location = {Athens, Greece}, pdf = {https://www.itec.aau.at/bib/files/Towards_an_Improved_SVC2AVCRewriter_MMEDIA2010_Sablatschan.pdf}, talkdate = {2010.06.14}, talktype = {registered}, url = {http://www.iaria.org/conferences2010/MMEDIA10.html} } @InProceedings{Ransburg2010a, author = {Ransburg, Michael and Martínez Graciá, Eduardo and Sutinen, Tiia and Ortíz Murillo, Jordi and Sablatschan, Michael and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop SVCVision, in conjunction with the 6th International Mobile Multimedia Communications Conference (MobiMedia 2010)}, title = {Scalable Video Coding Impact on Networks}, year = {2010}, address = {Berlin, Heidelberg, New York}, editor = {Rodriguez, Jonathan and Tafazolli, Rahim and Verikoukis, Christos}, month = {sep}, pages = {571-581}, publisher = {Springer}, abstract = {This paper describes the CELTIC project on "Scalable Video Coding Impact on Networks" with the focus of designing a streaming system based on the Scalable Video Coding extension of the H.264/AVC standard. The system is designed to cope with streaming scenarios that can be classified in four use cases: session handover, network congestion, receiver heterogeneity and user driven adaptation. A complete overview of the architecture of the system is given. Two demonstration scenarios are described in detail, which point out the advantages of scalable video coding compared to single layer approaches in multimedia transmission and adaptation scenarios. A concluding section summarizes the work and provides an outlook to future work items.}, isbn13 = {SBN 978-3-642-35155-6}, keywords = {Scalable Video Coding, H.264/SVC, streaming, architecture, video adaptation}, language = {EN}, talktype = {none} } @InProceedings{Ransburg2010, author = {Ransburg, Michael and Jonke, Mario and Hellwagner, Hermann}, booktitle = {Proceedings of the First Workshop on Mobile Multimedia Networking (IWMMN 2010)}, title = {An Evaluation of Mobile End Devices in Multimedia Streaming Scenarios}, year = {2010}, address = {Heidelberg/Berlin, Germany}, editor = {Wang, Honggang and Xia, Jinchun}, month = {jun}, pages = {14}, publisher = {Springer}, abstract = {This paper compares handhelds based on the iPhone and Android operating systems in multimedia streaming scenarios. We simulate typical Internet network impairments, i.e. packet delay and packet loss, and evaluate their effects on the end devices. Additional evaluations include bandwidth overhead in icted by the different streaming approaches and traffic shape and fairness when both handhelds consume media simultaneously. Based on the quantitative evaluation, both approaches show weaknesses and strengths. A final qualitative discussion points out additional advantages for the streaming approach implemented in the iPhone operating system.}, doi = {10.1007/978-3-642-17758-3_31}, language = {EN}, location = {Chicago, IL, USA}, pdf = {https://www.itec.aau.at/bib/files/Ransburg_IWMMN10.pdf}, talkdate = {2010.06.30}, talktype = {registered}, url = {http://www.mobilware.org/2010/} } @InProceedings{OrtizMurillo2010, author = {Ortiz Murillo, Jordi and Ransburg, Michael and Martínez Graciá, Eduardo and Sablatschan, Michael and Gómez Skarmeta, Antonio and Hellwagner, Hermann}, booktitle = {Proceedings of the Workshop on Quality of Experience for Multimedia Content Sharing (QoEMCS 2010)}, title = {Towards User-driven Adaptation of H.264/SVC Streams}, year = {2010}, address = {Tampere, Finland}, editor = {Buchinger, Shelley and Lopes, Rui Jorge and Jumisko-Pyykkö, Satu and Zepernick, Hans-Jürgen}, month = {jun}, pages = {4}, publisher = {Tampere University of Technology}, abstract = {H.264/SVC enables runtime-efficient scalability in the spatial, temporal and fidelity dimension. Existing adaptation mechanisms facilitate this to automatically adapt the H.264/ SVC stream to the current usage environment without any user interaction. This paper argues that the Quality of Experience (QoE) of the end user can be enhanced by enabling him to manually adjust the adaptation if he wishes to do so. An approach which enables this is presented and evaluated. It is shown that by facilitating this approach an increased QoE is provided compared to automatic adaptation approaches. Finally, future work indicates the next steps in order to implement this approach.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Towards User-driven Adaptation of H.264-SVC Streams.pdf}, talktype = {none}, url = {http://dcti.iscte.pt/events/qoemcs/} } @Article{Lopez2010, author = {Lopez, Fernando and Jannach, Dietmar and Martínez, Jose Maria and Timmerer, Christian and García, Narciso and Hellwagner, Hermann}, journal = {Journal of Applied Intelligence}, title = {Bounded non-deterministic planning for multimedia adaptation}, year = {2010}, month = {jul}, pages = {32}, abstract = {This paper proposes a novel combination of arti- ficial intelligence planning and other techniques for improv- ing decision-making in the context of multi-step multime- dia content adaptation. In particular, it describes a method that allows decision-making (selecting the adaptation to perform) in situations where third-party pluggable multi- media conversion modules are involved and the multime- dia adaptation planner does not know their exact adapta- tion capabilities. In this approach, the multimedia adapta- tion planner module is only responsible for a part of the required decisions; the pluggable modules make additional decisions based on different criteria. We demonstrate that partial decision-making is not only attainable, but also in- troduces advantages with respect to a system in which these conversion modules are not capable of providing additional decisions. This means that transferring decisions from the multi-step multimedia adaptation planner to the pluggable conversion modules increases the flexibility of the adapta- tion. Moreover, by allowing conversion modules to be only partially described, the range of problems that these modules can address increases, while significantly decreasing both the description length of the adaptation capabilities and the planning decision time. Finally, we specify the conditions under which knowing the partial adaptation capabilities of a set of conversion modules will be enough to compute a proper adaptation plan.}, address = {Springer New York}, doi = {10.1007/s10489-010-0242-3}, keywords = {Bounded non-deterministic multimedia adaptation, Planning, Decision-making, MPEG-7, MPEG-21}, language = {EN}, publisher = {Springer}, url = {http://www.springerlink.com/content/751g123vp1574qt5/} } @InProceedings{Kuschnig2010a, author = {Kuschnig, Robert and Kofler, Ingo and Hellwagner, Hermann}, booktitle = {Proceedings of the First Annual ACM SIGMM Conference on Multimedia Systems (MMSys)}, title = {An Evaluation of TCP-based Rate-control Algorithms for Adaptive Internet Streaming of H.264/SVC}, year = {2010}, address = {New York, NY, USA}, editor = {Feng, Wu-chi and Mayer-Patel, Ketan}, month = {feb}, pages = {157-168}, publisher = {ACM}, abstract = {Recent work in TCP video streaming indicates that multimedia streaming via TCP provides satisfactory performance when the achievable TCP throughput is approximately twice the media bit rate. However, these conditions may not be achievable on the Internet, e.g., when the delivery path offers insufficient bandwidth or becomes congested due to competing traffic. Therefore, adaptive streaming for videos over TCP is required and a number of rate-control algorithms for video streaming have been proposed and evaluated in the literature. In this paper, we evaluate and compare three existing rate-control algorithms for TCP streaming in terms of the (PSNR) quality of the delivered video and in terms of the timeliness of delivery. The contribution of the paper is that, to the best of our knowledge, this is the first evaluation of TCP-based streaming in an Internet-like setting making use of the scalability features of the H.264/SVC video codec. Two simple bandwidth estimation algorithms and a priority-/deadline-driven approach are described to adapt the bit rates of, and transmit, the H.264/SVC video in a rate-distortion optimal manner. The results indicate that the three algorithms perform robustly in terms of video quality and timely delivery, both on under-provisioned links and in case of competing TCP flows. The priority-/deadline-driven technique is even more stable in terms of packet delays and jitter; thus, client buffers can be dimensioned more easily.}, doi = {10.1145/1730836.1730856}, language = {EN}, location = {Scottsdale, AZ, USA}, pdf = {https://www.itec.aau.at/bib/files/MMSYS10_Kuschnig_Evaluation_TCP_based_Rate_Control.pdf}, talkdate = {2010.02.23}, talktype = {registered}, url = {http://www.mmsys.org} } @InProceedings{Kuschnig2010, author = {Kuschnig, Robert and Kofler, Ingo and Hellwagner, Hermann}, booktitle = {Proceedings of the 7th IEEE Consumer Communications and Networking Conference (CCNC)}, title = {Improving Internet Video Streaming Performance by Parallel TCP-Based Request-Response Streams}, year = {2010}, address = {Los Alamitos, CA, USA}, editor = {Balandin, Sergey and Matuszewksi, Marcin and Ott, Jörg}, month = {jan}, pages = {5}, publisher = {IEEE}, abstract = {TCP-based video streaming encounters difficulties in unreliable networks with unanticipated packet loss. In combination with high round trip times, the effective throughput deteriorates rapidly and TCP connection resets or stalls may occur. In this paper, we propose a client-driven video transmission scheme which utilizes multiple HTTP/TCP streams. The scheme is largely insensitive to unanticipated packet loss and thereby reduces throughput fluctuations. Since it is based on HTTP, the scheme can easily be deployed in existing network infrastructures. It fosters scalability on the server side by shifting complexity from the server to the clients. Certain features of request-response schemes allow maintaining fairness, despite of using multiple HTTP streams. Making use of TCP, the scheme inherently adapts to congested network links.}, doi = {10.1145/1730836.1730856}, language = {EN}, location = {Las Vegas, NV, USA}, pdf = {https://www.itec.aau.at/bib/files/CCNC10_Kuschnig_Request_Response_Streams.pdf}, talkdate = {2010.01.10}, talktype = {registered}, url = {http://www.ieee-ccnc.org/2010} } @InProceedings{Eberhard2010, author = {Eberhard, Michael and Szkaliczki, Tibor and Hellwagner, Hermann and Szobonya, László and Timmerer, Christian}, booktitle = {Proceedings of the 2010 ACM Workshop on Advanced Video Streaming Techniques for Peer-to-Peer Networks and Social Networking}, title = {Knapsack Problem-based Piece-Picking Algorithms for Layered Content in Peer-to-Peer Networks}, year = {2010}, address = {New York, NY, USA}, editor = {Olmo, Gabriella and Timmerer, Christian and Frossard, Pascal and Mitchell, Keith}, month = {oct}, pages = {71--76}, publisher = {ACM}, series = {AVSTP2P}, abstract = {The distribution of layered content over peer-to-peer networks becomes more important today as the users are consuming the content on terminals with various display capabilities and different network connections. For single-layer content distribution, the piece-picking algorithm only needs to ensure that content pieces are downloaded in time for display. When layered content is distributed over a peer-to-peer network, the piece-picking algorithm needs to be modified to ensure that the best possible quality is displayed while all desired pieces still have to be received before their deadline expires. In this paper, the piece-picking problem for layered content is analyzed and a number of piece-picking algorithms for layered content based on the solutions for the knapsack problem are presented. Furthermore, an evaluation of these algorithms is performed and possible applications are discussed.}, doi = {10.1145/1877891.1877908}, isbn13 = {978-1-4503-0169-5}, keywords = {knapsack problem, layered/scalable content, piece utility calculation, piece-picking}, language = {EN}, location = {Firenze, Italy}, pdf = {https://www.itec.aau.at/bib/files/avst1524-eberhard.pdf}, talkdate = {2010.10.29}, talktype = {poster}, url = {http://www.p2pstreaming.eu} } @InProceedings{Waltl2009, author = {Waltl, Markus and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the First International Workshop on Quality of Multimedia Experience (QoMEX 2009)}, title = {A Test-Bed for Quality of Multimedia Experience Evaluation of Sensory Effects}, year = {2009}, address = {Los Alamitos, CA, USA}, editor = {Ebrahim, Touradj and El-Maleh, Khaled and Dane, Gokce and Karam, Lina}, month = {jul}, pages = {145-150}, publisher = {IEEE}, abstract = {This paper introduces a prototype test-bed for triggering sensory effects like light, wind, or vibration when presenting audiovisual resources, e.g., a video, to users. The ISO/IEC MPEG is currently standardizing the Sensory Effect Description Language (SEDL) for describing such effects. This language is briefly described in the paper and the testbed that is destined to evaluate the quality of the multimedia experience of users is presented. It consists of a video annotation tool for sensory effects, a corresponding simulation tool, and a real test system. Initial experiments and results on determining the color of light effects from the video content are reported.}, doi = {10.1109/QOMEX.2009.5246962}, isbn13 = {978-1-4244-4370-3}, issn = {978-1-4244-43}, keywords = {Sensory Information, MPEG-V}, language = {EN}, location = {San Diego, CA}, pdf = {https://www.itec.aau.at/bib/files/qomex2009_mwcthh.pdf}, talkdate = {2009.07.31}, talktype = {registered}, url = {http://www.qomex2009.org} } @InProceedings{Timmerer2009a, author = {Timmerer, Christian and Gelissen, Jean and Waltl, Markus and Hellwagner, Hermann}, booktitle = {Proceedings of the 2009 NEM Summit}, title = {Interfacing with Virtual Worlds}, year = {2009}, address = {Heidelberg}, editor = {Hrasnica, Halid}, month = sep, pages = {118-123}, publisher = {Eurescom – the European Institute for Research and Strategic Studies in Telecommunications – GmbH}, abstract = {Virtual worlds (often referred to as 3D3C for 3D visualization & navigation and the 3C’s of Community, Creation and Commerce) integrate existing and emerging (media) technologies (e.g. instant messaging, video, 3D, VR, AI, chat, voice, etc.) that allow for the support of existing and the development of new kinds of networked services. The emergence of virtual worlds as platforms for networked services is recognized by businesses as an important enabler as it offers the power to reshape the way companies interact with their environments (markets, customers, suppliers, creators, stakeholders, etc.) in a fashion comparable to the Internet and to allow for the development of new (breakthrough) business models, services, applications and devices. Each virtual world however has a different culture and audience making use of these specific worlds for a variety of reasons. These differences in existing Metaverses permit users to have unique experiences. In order to bridge these differences in existing and emerging Metaverses a standardized framework is required, i.e., MPEG-V Media Context and Control (ISO/IEC 23005), that will provide a lower entry level to (multiple) virtual worlds both for the provider of goods and services as well as the user. The aim of this paper is to provide an overview of MPEG-V and its intended standardization areas. Additionally, a review about MPEG-V’s most advanced part – Sensory Information – is given.}, issn = {9783000289538}, keywords = {MPEG-V}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/nem2009_ctjgmwhh.pdf}, talktype = {none}, url = {http://www.nem-summit.eu} } @InProceedings{Timmerer2009, author = {Timmerer, Christian and Jaborning, Johannes and Hellwagner, Hermann}, booktitle = {Proceedings of the 9th Workshop on Multimedia Metadata (WMM'09)}, title = {A Comparison and Mapping Model}, year = {2009}, address = {Aachen, Germany}, editor = {Klamma, Ralf and Grigoras, Romulus and Charvillat, Vincent and Kosch, Harald}, month = mar, pages = {18}, publisher = {http://ceur-ws.org}, abstract = {Nowadays, mobile devices have implemented several transmission technologies which enable access to the Internet and increase the bit rate for data exchange. Despite modern mobile processors and high-resolution displays, mobile devices will never reach the stage of a powerful notebook or desktop system (for example, due to the fact of battery powered CPUs or just concerning the smallsized displays). Due to these limitations, the deliverable content for these devices should be adapted based on their capabilities including a variety of aspects (e.g., from terminal to network characteristics). These capabilities should be described in an interoperable way. In practice, however, there are many standards available and a common mapping model between these standards is not in place. Therefore, in this paper we describe such a mapping model and its implementation aspects. In particular, we focus on the whole delivery context (i.e., terminal capabilities, network characteristics, user preferences, etc.) and investigated the two most prominent state-of-the-art description schemes, namely User Agent Profile (UAProf) and Usage Environment Description (UED).}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/DC-paper-v.2.pdf}, talktype = {none}, url = {http://ceur-ws.org/Vol-441/pxx.pdf} } @InProceedings{Reiterer2009b, author = {Reiterer, Bernhard and Concolato, Cyril and Hellwagner, Hermann}, booktitle = {Proceedings of 1st International ICST Conference on User Centric Media - UCMedia 2009}, title = {Natural-Language-based Conversion of Images to Mobile Multimedia Experiences}, year = {2009}, address = {Berlin, Heidelberg, New York}, editor = {Daras, Patros and Chlamtac, Imrich}, month = dec, pages = {4 - CD}, publisher = {Springer}, series = {LNICST - Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering}, abstract = {We describe an approach for viewing any large, detail-rich picture on a small display by generating a video from the image, as taken by a virtual camera moving across it at varying distance. Our main innovation is the ability to build the virtual camera's motion from a textual description of a picture, e.g., a museum caption, so that relevance and ordering of image regions are determined by co-analyzing image annotations and natural language text. Furthermore, our system arranges the resulting presentation such that it is synchronized with an audio track generated from the text by use of a text-to-speech system.}, issn = {9789639799844}, keywords = {image adaptation - text analysis - image annotation - digital cultural heritage - computer animation}, language = {EN}, talktype = {none}, url = {http://www.usercentricmedia.org/index.shtml} } @InProceedings{Reiterer2009a, author = {Reiterer, Bernhard and Hellwagner, Hermann}, booktitle = {Proceedings International InterMedia Summer School 2009}, title = {Animated Picture Presentation Steered by Natural Language}, year = {2009}, address = {Geneva}, editor = {Nadia, Magnenat-Thalmann and Seunghyun, Han and Dimitris, Potopsaltou}, month = jun, pages = {24-32}, publisher = {MIRALab at University of Geneva}, series = {International InterMedia Summer School}, abstract = {In this paper, we present an approach for presenting large, feature-rich pictures on small displays by generating an animation and subsequently a video from the image, as it could be taken by a virtual camera moving across the image. Our main innovation is the ability to build the virtual camera's motion upon a textual description of a picture, as from a museum caption, so that relevance and ordering of image regions is determined by co-analyzing image annotations and text. Furthermore, our system can arrange the resulting presentation in a way that it is synchronized with an audio track generated from the text by use of a text-to-speech system.}, keywords = {image adaptation, text parsing, image annotation, digital cultural heritage, computer animation}, language = {EN}, talktype = {none}, url = {http://intermediaschool.miralab.unige.ch/} } @InProceedings{Reiterer2009, author = {Reiterer, Bernhard and Lachner, Janine and Lorenz, Andreas and Zimmermann, Andreas and Hellwagner, Hermann}, booktitle = {Advances in Semantic Media Adaptation and Personalization}, title = {Research Directions Toward User-centric Multimedia}, year = {2009}, address = {Boca Raton (Florida)}, editor = {Angelides, Marios C and Mylonas, Phivos and Wallace, Manolis}, month = mar, pages = {21-42}, publisher = {Auerbach Publications}, abstract = {Currently, much research aims at coping with the shortcomings in multimedia consumption that may exist in a user's current context, e.g., due to the absence of appropriate devices at many locations, a lack of capabilities of mobile devices, restricted access to content, or non-personalized user interfaces. Recently, solutions to specific problems have been emerging, e.g., wireless access to multimedia repositories over standardized interfaces; however, due to usability restrictions the user has to spend much effort to or is even incapable of fulfilling his/her demands. The vision of user-centric multimedia places the user in the center of multimedia services to support his/her multimedia consumption intelligently, dealing with the aforementioned issues while minimizing required work. Essential features of such a vision are comprehensive context awareness, personalized user interfaces, and multimedia content adaptation. These aspects are addressed in this paper as major challenges toward a user-centric multimedia framework.}, doi = {10.1201/9781420076653-c2}, edition = {2}, isbn10 = {1420076647}, isbn13 = {978-1420076646}, issn = {9781420076646}, language = {EN}, talktype = {none}, url = {http://www.crcpress.com/product/isbn/9781420076646} } @InProceedings{Kofler2009a, author = {Kofler, Ingo and Kuschnig, Robert and Hellwagner, Hermann}, booktitle = {Proceedings of the IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB)}, title = {Improving IPTV Services by H.264/SVC Adaptation and Traffic Control}, year = {2009}, address = {Los Alamitos, CA, USA}, editor = {Angueira, Pablo and Reimers, Ulrich}, month = may, pages = {1-6}, publisher = {IEEE}, series = {BMSB}, abstract = {This paper presents a novel approach that combines both in-network, application-layer adaptation and network-layer traffic control of scalable video streams based on the H.264/SVC standard. In the IPTV/VoD scenario considered, an intercepting RTSP/RTP proxy performs admission control of the requested video, based on the signaled scalability information, and decides whether the content can be streamed without changes or in an adapted version. The proxy configures the network layer appropriately in order to separate the video stream from besteffort traffic on the same link. Rather than performing fixed bandwidth allocation, our proxy approach uses the Hierarchical Token Bucket (HTB) queuing discipline to allow for borrowing bandwidth between traffic classes. In that setting, two different allocation policies are introduced. The Hard Reservation Policy (HRP) performs admission control and adaptation on the video streams and does not modify video bandwidth allocation after admission. In contrast, the Flexible Borrowing Policy (FBP) restricts the admission control to the base layer of the SVC stream. The packets carrying MGS enhancement layer data are marked with priorities by the proxy and are handled at the network layer by a priority-based queuing mechanism. Both a qualitative comparison and an experimental evaluation of the two policies are given.}, doi = {10.1109/ISBMSB.2009.5133771}, isbn13 = {9781424425907}, language = {EN}, location = {Bilbao, Spain}, talkdate = {2009.05.14}, talktype = {registered}, url = {https://www.itec.aau.at/publications/mmc/BMSB09_Kofler_Improving_IPTV_Services_Preprint.pdf} } @InProceedings{Kofler2009, author = {Kofler, Ingo and Kuschnig, Robert and Hellwagner, Hermann}, booktitle = {Proceedings of the 6th IEEE Consumer Communications and Networking Conference (CCNC)}, title = {In-Network Real-Time Adaptation of Scalable Video Content on a WiFi-ne Router}, year = {2009}, address = {Los Alamitos, CA, USA}, editor = {Gibbs, Simon and Messer, Alan}, month = jan, pages = {2}, publisher = {IEEE}, series = {CCNC}, abstract = {One of the most active research topics in the field of video signal processing is scalable video coding (SVC). The recently published extension of the H.264/AVC video coding standard introduces scalability features by employing a layered encoding of the video stream. In our work we investigated the usage of this scalable extension of H.264/AVC for in-network multimedia adaptation. We developed an RTSP/RTP-based proxy which exploits the layered encoding of the video and can perform real-time video adaptation on an inexpensive off-the-shelf WiFi router. This is achieved by applying a stateful, packet-based adaptation approach that keeps the computational costs at a minimum. With that approach it is possible to simultaneously adapt multiple video streams to varying network conditions or to the capabilities of the consumers' end-devices. In our demonstration we show the streaming of two scalable video streams from a server to a client and the in-network adaptation of the video at the WiFi router. The adaptation can be controlled interactively in the temporal, spatial and SNR domains.}, doi = {10.1109/CCNC.2009.4785005}, isbn13 = {9781424423088}, language = {EN}, location = {Las Vegas, NV, USA}, pdf = {https://www.itec.aau.at/bib/files/CCNC09_SVC_Adaptation_Router_preprint.pdf}, talkdate = {2009.01.11}, talktype = {poster} } @Article{Hellwagner2009, author = {Hellwagner, Hermann and Kuschnig, Robert and Stütz, Thomas and Uhl, Andreas}, journal = {Journal on Signal Processing: Image Communication}, title = {Efficient In-Network Adaptation of Encrypted {H.264/SVC} Content}, year = {2009}, month = {jul}, number = {9}, pages = {740-758}, volume = {24}, abstract = {This paper addresses the efficient adaptation of encrypted scalable video content (H.264/SVC). RTP-based in-network adaptation schemes on a media aware network element (MANE) in an IPTV and VoD scenario are considered. Two basic alternatives to implement encryption and adaptation of H.264/SVC content are investigated: (i) full, format-independent encryption making use of Secure RTP (SRTP); (ii) SVC-specific encryption that leaves the metadata relevant for adaptation (NAL unit headers) unencrypted. The SRTP-based scheme (i) is straightforward to deploy, but requires the MANE to be in the security context of the delivery, i.e., to be a trusted node. For adaptation, the content needs to be decrypted, scaled, and re-encrypted. The SVC-specific approach (ii) enables both full and selective encryption, e.g., of the base layer only. SVC-specific encryption is based on own previous work, which is substantially extended and detailed in this paper. The adaptation MANE can now be an untrusted node; adaptation becomes a low-complexity process, avoiding full decryption and re-encryption of the content. This paper presents the first experimental comparison of these two approaches and evaluates whether multimedia-specific encryption can lead to performance and application benefits. Potential security threats and security properties of the two approaches in the IPTV and VoD scenario are elementarily analyzed. In terms of runtime performance on the MANE our SVC-specific encryption scheme significantly outperforms the SRTP-based approach. SVC-specific encryption is also superior in terms of induced end-to-end delays. The performance can even be improved by selective application of the SVC-specific encryption scheme. The results indicate that efficient adaptation of SVC-encrypted content on low-end, untrusted network devices is feasible.}, address = {Amsterdam}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Elsevier_SPIC_Hellwagner09a.pdf}, publisher = {Elsevier B.V.} } @InProceedings{Ferscha2009, author = {Ferscha, Alois and Hellwagner, Hermann and Neuper, Christa and Pree, Wolfgang}, booktitle = {Informatik macht Zukunft - Zukunft macht Informatik}, title = {Zukunft der Informatik}, year = {2009}, address = {Wien}, editor = {Chroust, Gerhard and Moessenboeck, Hans-Peter}, month = dec, pages = {48-51}, publisher = {Oesterreichische Computer Gesellschaft}, isbn10 = {9783854032588}, language = {DE}, talktype = {none} } @Article{Eberhard2009a, author = {Eberhard, Michael and Timmerer, Christian and Quacchio, Emanuele and Hellwagner, Hermann}, journal = {IEEE Wireless Communications}, title = {An Interoperable Delivery Framework for Scalable Media Resources}, year = {2009}, month = {oct}, number = {Vol. 16, No. 5}, pages = {58-63}, volume = {Oktober 2009}, abstract = {In this paper, an interoperable framework for the delivery of scalable media resources, e.g., in the standardized Scalable Video Coding (SVC) format, is presented. The framework provides support for Video on Demand (VoD) as well as multicast streaming and performs an efficient, generic, and interoperable adaptation of the streamed content based on MPEG-21 Digital Item Adaptation (DIA). The server as well as the clients of the streaming framework implement the MPEG Extensible Middleware (MXM) and utilize the MPEG Query Format (MPQF) for querying the available media resources. The framework has been fully integrated into the VLC media player. The architecture for both, VoD and multicast is presented in detail. Finally, a comparison in terms of performance of the generic MPEG-21 metadata-based adaptation approach to an SVC-specific adaptation approach is provided.}, address = {Los Alamitos, CA, USA}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/ieeewireless_eberhard.pdf}, publisher = {IEEE} } @InProceedings{Eberhard2009, author = {Eberhard, Michael and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {STreaming Day ’09 Proceedings}, title = {A Layered Piece-Picking Algorithm for Peer-to-Peer Networks}, year = {2009}, address = {NA}, editor = {Raggio, Marko and Rovati, Fabrizio}, month = sep, pages = {n.a.}, publisher = {NA}, abstract = {The streaming of multimedia content over Peer-to-Peer (P2P) networks is nowadays a well appreciated concept, as it helps distributing content to a great number of users and additionally reduces the server costs for providing the content. As the users of P2P networks often have different bandwidth connections and terminals, the same content is usually provided in different qualities. Although such a provision of the same content in different qualities helps to satisfy all users, it makes the sharing process less efficient. Users that are interested in the content in a specific quality can only exchange pieces with those users that are interested in the same content and the same quality. Thus, layered video coding, which provides different qualities within one bitstream, is especially well suited for P2P distribution. If the layered content is provided once in the best quality, all peers interested in this content can at least exchange the base layer, plus the enhancement layers they are interested in with those peers that have them available.}, issn = {9781616236212}, language = {EN}, location = {Genova, Italy}, talkdate = {2009.09.21}, talktype = {registered} } @Article{Tusch2008, author = {Tusch, Roland and Jakab, Michael and Köpke, Julius and Krätschmer, Armin and Kropfberger, Michael and Kuchler, Sigrid and Ofner, Michael and Hellwagner, Hermann and Böszörmenyi, Laszlo}, journal = {International Journal of Digital Multimedia Broadcasting}, title = {Context-Aware UPnP-AV Services for Adaptive Home Multimedia Systems}, year = {2008}, month = sep, pages = {12}, volume = {Vol. 2008}, abstract = {One possibility to provide mobile multimedia in domestic multimedia systems is the use of Universal Plug and Play Audio Visual (UPnP-AV) devices. In a standard UPnP-AV scenario, multimedia content provided by a Media Server device is streamed to Media Renderer devices by the initiation of a Control Point. However, there is no provisioning of context-aware multimedia content customization. This paper presents an enhancement of standard UPnP-AV services for home multimedia environments regarding context awareness. It comes up with context profile definitions, shows how this context information can be queried from the Media Renderers, and illustrates how a Control Point can use this information to tailor a media stream from the Media Server to one or more Media Renderers. Moreover, since a standard Control Point implementation only queries one Media Server at a time, there is no global view on the content of all Media Servers in the UPnP-AV network. This paper also presents an approach of multimedia content integration on the Media Server side that provides fast search for content on the network. Finally, a number of performance measurements show the overhead costs of our enhancements to UPnP-AV in order to achieve the benefits.}, address = {Cairo}, doi = {doi:10.1155/2008/835438}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Context-Aware UPnP-AV Services for Adaptive Home Multimedia Systems.pdf}, publisher = {Hindawi Publishing Corporation}, url = {http://www.hindawi.com/journals/ijdmb/volume-2008/} } @InProceedings{Timmerer2008h, author = {Timmerer, Christian and Ransburg, Michael and Kofler, Ingo and Hellwagner, Hermann and Souto, Pedro and Andrade, Maria and Carvalho, Pedro and Castro, Helder and Sidibe, Mamadou and Mehaoua, Ahmed and Fang, Li and Lindsay, Adam and Mackay, Michael and Lugmayr, Artur and Feiten, Bernhard}, booktitle = {Proceedings of the 2nd European Symposium on Mobile Media Delivery (EUMOB)}, title = {An Integrated Management Supervisor for End-to-End Management of Heterogeneous Contents, Networks, and Terminals enabling Quality of Service}, year = {2008}, address = {New York, NY, USA}, editor = {Frantti, Tapio and Huusko, Jyrki}, month = jul, pages = {6}, publisher = {ACM}, series = {EUMOB}, abstract = {End-to-end support for Quality of Service (QoS) has been broadly discussed in the literature. Many technologies have been proposed, each focusing on specific aspects for providing QoS guarantees to the end user. However, the integrated management of the end-to-end chain preserving QoS in heterogeneous environments is still a significant issue and insufficiently addressed to date. In this paper we propose an integrated management supervisor that takes into account the requirements from all stakeholders along the multimedia content delivery chain and provides an end-to-end management solution enabling QoS to the end user. This architecture and the subsystems that can be distributed along the end-to-end chain are detailed in this paper.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/eumob2008enthrone.pdf}, talktype = {none} } @Article{Timmerer2008g, author = {Timmerer, Christian and Hellwagner, Hermann}, journal = {Informatik Spektrum}, title = {Das MPEG-21 Multimedia Framework}, year = {2008}, month = dec, number = {6}, pages = {576-579}, volume = {31}, address = {Berlin, Heidelberg, New York}, language = {DE}, publisher = {Springer} } @InCollection{Timmerer2008e, author = {Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Encyclopedia of Multimedia}, publisher = {Springer}, title = {MPEG-21 Multimedia Framework}, year = {2008}, address = {Berlin, Heidelberg, New York}, edition = {2}, editor = {Furht, Borko}, month = oct, pages = {463-469}, isbn10 = {0387747249}, isbn13 = {978-0387747248}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Encyclopedia_MM_M21_pre.pdf} } @InCollection{Timmerer2008d, author = {Timmerer, Christian and Vetro, Anthony and Hellwagner, Hermann}, booktitle = {Encyclopedia of Multimedia}, publisher = {Springer}, title = {MPEG-21 Digital Item Adaptation}, year = {2008}, address = {Berlin, Heidelberg, New York}, edition = {2}, editor = {Furht, Borko}, month = oct, pages = {457-463}, isbn10 = {0387747249}, isbn13 = {978-0387747248}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Encyclopedia_MM_M21_DIA_pre.pdf} } @InCollection{Timmerer2008b, author = {Timmerer, Christian and Ransburg, Michael and Hellwagner, Hermann}, booktitle = {Encyclopedia of Multimedia}, publisher = {Springer}, title = {Generic Multimedia Content Adaptation}, year = {2008}, address = {Berlin, Heidelberg, New York}, edition = {2}, editor = {Furht, Borko}, month = oct, pages = {263-271}, isbn10 = {0387747249}, isbn13 = {978-0387747248}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Encyclopedia_MM_gBSD_pre.pdf} } @Book{Timmerer2008a, author = {Timmerer, Christian and Hellwagner, Hermann}, publisher = {IEEE}, title = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, year = {2008}, address = {Los Alamitos, CA, USA}, month = apr, series = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, isbn10 = {076953130X}, isbn13 = {9780769531304}, language = {EN}, pages = {246}, url = {http://www2.computer.org/portal/web/csdl/abs/proceedings/wiamis/2008/3130/00/3130toc.htm} } @Article{Reiterer2008, author = {Reiterer, Bernhard and Concolato, Cyril and Lachner, Janine and Le Feuvre, Jean and Moissinac, Jean-Claude and Lenzi, Stefano and Chessa, Stefano and Ferrá, Enrique Fernández and Menaya, Juan José González and Hellwagner, Hermann}, journal = {The Visual Computer, International Journal of Computer Graphics}, title = {User-centric universal multimedia access in home networks}, year = {2008}, issn = {01782789}, month = jul, number = {7-9}, pages = {837-845}, volume = {24}, abstract = {Much research is currently being conducted towards Universal Multimedia Access, aiming at removing barriers that arise when multimedia content is to be consumed with more and more heterogeneous devices and over diverse networks. We argue that users should be put at the center of the research work to enable user-centric multimedia access. In this paper we present the requirements for a user-centric multimedia access system in a networked home environment. These requirements are easy access to available content repositories, context awareness, content adaptation and session migration. After showing the limits of state-of-the-art technologies, we present the architecture of a system which allows unified access to the home network content, automatically delivered to rendering devices close to the user, adapted according to the rendering device constraints, and which is also capable of session mobility.}, address = {Berlin, Heidelberg, New York}, doi = {10.1007/s00371-008-0265-5}, keywords = {Universal Multimedia Access · Multimedia adaptation · UPnP AV · Context awareness · Content sharing}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/User-centric universal multimedia access in home networks.pdf}, publisher = {Springer}, url = {http://http://www.springerlink.com/content/fpjj19237704788k/} } @InProceedings{Ransburg2008a, author = {Ransburg, Michael and Gressl, Hubert and Hellwagner, Hermann}, booktitle = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, title = {Efficient Transformation of MPEG-21 Metadata for Codec-agnostic Adaptation in Real-time Streaming Scenarios}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Hellwagner, Hermann and Timmerer, Christian}, month = apr, pages = {143-146}, publisher = {IEEE}, abstract = {Scalable media contents, such as the new MPEG-4 Scalable Video Codec enable to easily retrieve different qualities of the media content by simply disregarding certain media segments. The MPEG-21-based codec-agnostic adaptation approach supports this concept by introducing an XMLbased Bitstream Syntax Description (BSD) which describes the different segments of a media content. Based on this BSD, an adaptation node can intelligently adapt any scalable media (i.e., remove specific media segments) without the need for codec-specific knowledge. The adaptation approach consists of 1) transforming this BSD and 2) adapting the media based on the transformed BSD. In this paper, we focus on the BSD transformation step and evaluate different mechanisms w.r.t. their transformation efficiency given several application scenarios. In particular, we compare the traditional stylesheet-based mechanisms with a novel mechanism based on regular expressions. We discuss both mechanisms in terms of their expressiveness, and propose how to actually employ regular expressions for codec-agnostic adaptation. Finally, we quantitatively evaluate these mechanisms in different adaptation scenarios, which vary in the size and number of required BSD units}, isbn13 = {9780769531304}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Efficient Transformation of MPEG-21 Metadata for Codec-agnostic Adaptation.pdf}, talktype = {none}, url = {http://www2.computer.org/portal/web/csdl/abs/proceedings/wiamis/2008/3130/00/3130toc.htm} } @InProceedings{Ransburg2008, author = {Ransburg, Michael and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Multimedia Semantics: The role of Metadata}, title = {Dynamic and Distributed Multimedia Content Adaptation based on the MPEG-21 Multimedia Framework}, year = {2008}, address = {Berlin, Heidelberg, New York}, editor = {Lux, Mathias and Granitzer, Michael and Spaniol, Marc}, month = feb, pages = {3-24}, publisher = {Springer}, abstract = {Today, there are many technologies in place to establish an infrastructure for the delivery and consumption of multimedia content. In practice, however, several elements of such an infrastructure are often stand-alone systems and a big picture of how these elements relate to each other or even fit together is not available. Therefore, MPEG-21 aims to provide an open framework for interoperable multimedia delivery and consumption. This requirement for interoperability results in a great diversity of XML-based metadata, which describes the media data on semantic or syntactic levels, in order to make it more accessible to the user. This metadata can be of considerable size, which leads to problems in streaming scenarios. Other than media data, XML metadata has no concept of samples, thus inhibiting streamed (and timed) processing, which is natural for media data. In order to address the challenges and requirements resulting from this situation, the concept of streaming instructions is introduced. These streaming instructions facilitate the fragmentation of content-related metadata, the association of media and metadata fragments with each other, and the synchronized streaming and processing of those fragments. Based on these capabilities, a dynamic and distributed multimedia content adaptation framework can be built.}, doi = {10.1007/978-3-540-77473-0_1}, isbn10 = {3540774726}, isbn13 = {978-3540774723}, language = {EN}, talktype = {none} } @InProceedings{Quaritsch2008, author = {Quaritsch, Markus and Stojanovski, Emil and Bettstetter, Christian and Friedrich, Gerhard and Hellwagner, Hermann and Rinner, Bernhard and Hofbaur, Michael and Shah, Mubarak}, booktitle = {Proceedings of the Second International Conference on Autonomic Computing and Communication Systems}, title = {Collaborative Microdrones: Applications and Research Challenges}, year = {2008}, address = {New York, NY, USA}, editor = {ACM,}, month = jul, pages = {7}, publisher = {ACM Press}, abstract = {Microdrones are small-scale unmanned aerial vehicles (UAVs) carrying payloads such as cameras and sensors. Such microdrones enable us to obtain a bird's eye view of the environment which is helpful in many applications such as environmental monitoring, surveillance or disaster management. This position paper reports on our recently launched project \collaborative microdrones" where we are developing a system for aerial imaging based on cooperating, wireless networked microdrones that can be used in disaster management applications. Several microdrones will y in formation over the area of interest and deliver sensor data which is fused, analyzed and delivered to the user in real-time. In this paper we brie y discuss applications for UAVs, present related projects, introduce our research focus and report on preliminary results.}, keywords = {microdrones, networked autonomous systems, mission planning, aerial imaging, formation flight}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Collaborative Microdrones.pdf}, talktype = {none}, url = {http://www.pervasive.uni-klu.ac.at/publications/pdf/Quaritsch_Autonomics2008.pdf} } @InProceedings{Prangl2008a, author = {Prangl, Martin and Kofler, Ingo and Hellwagner, Hermann}, booktitle = {Proceedings of the 4th International Conference on Networking and Services (ICNS)}, title = {Towards QoS Improvements of TCP-based Media Delivery}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Bi, Jun and Chin, Kim and Dini, Cosmin and Lehmann, Leo and Pheanis, David C}, month = mar, pages = {188-193}, publisher = {IEEE}, series = {ICNS}, abstract = {The amount of audiovisual data available on the Internet and thus of multimedia communication over today's networks is increasing at a rapid pace. Despite the availability of specific media transport protocols like RTP, most content providers make use of the well-established and reliable TCP protocol to deliver audiovisual content over the Internet. The reason is that TCP-based data delivery in general is much less complicated for the clients to be served and over today's networks traversed (including proxies and firewalls), than making use of UDP-based RTP connections. However, in case of network bandwidth fluctuations and packet losses, TCP-based media delivery may lead to annoying jerky playback at the client side, due to retransmissions and late arrival of media data. This papers deals with TCP-based perceptual QoS improvement mechanisms for increasing the media experience for the consumer under unstable network conditions. Our approach is based on media content adaptation (transcoding) to fit the actual network bandwidth continuously monitored by the sender. The proposed mechanisms are applied at the application level at the server side, leaving the existing TCP implementation untouched and therefore enabling transparent use of existing media players. An evaluation of a realistic use case is presented which underlines the efficency of our approach.}, doi = {10.1109/ICNS.2008.10}, isbn13 = {978-0-7695-3094-9}, language = {EN}, location = {Gosier, Guadaloupe}, pdf = {https://www.itec.aau.at/bib/files/prangl-tQosTcpMediaDelivery.pdf}, talkdate = {2008.03.19}, talktype = {registered} } @InProceedings{Prangl2008, author = {Prangl, Martin and Kofler, Ingo and Hellwagner, Hermann}, booktitle = {Proceedings of the 1st International Conference on Ambient Media and Systems (Ambi-sys)}, title = {An MPEG-21-driven Utility-based Multimedia Adaptation Decision Taking Web Service}, year = {2008}, address = {Brussels, Belgium}, editor = {Whitaker, Roger M and Liang, Ben}, month = feb, pages = {8}, publisher = {ICST}, series = {Ambi-sys}, abstract = {Supporting transparent delivery and convenient use of multimedia content across a wide range of networks and devices is still a challenging task within the multimedia research community; Universal Multimedia Access (UMA) is a vision that has been pursued for quite some time. In multimedia frameworks, content adaptation is the core concept to make progress toward this goal. Most media adaptation engines targeting UMA scale the content w.r.t. terminal capabilities and network resource constraints and do not sufficiently consider end user preferences or even the utility of the adapted content for the user. Based on our previous work and the support of the MPEG-21 framework, we present a transparent solution to provide a content utility-aware adaptation decision for such utility-unaware multimedia frameworks. The idea is to outsource the challenging utility-aware adaptation decision taking task, which takes many factors into consideration and leads to a complex optimization problem. A realistic use case is adopted to show how related external multimedia frameworks can easily integrate and use our proposed adaptation decision taking Web Service.}, isbn13 = {978-963-9799-16-5}, language = {EN}, location = {Quebec, Canada}, pdf = {https://www.itec.aau.at/bib/files/ADTService-final.pdf}, talkdate = {2008.02.12}, talktype = {registered} } @Article{Mylonas2008, author = {Mylonas, Phivos and Hellwagner, Hermann and Castells, Pablo and Wallace, Manolis}, journal = {Signal, Image and Video Processing}, title = {Signal, image and video processing (SIVP) special issue on “multimedia semantics, adaptation and personalization” Editorial}, year = {2008}, issn = {1863-1711}, month = oct, number = {4}, pages = {287-288}, volume = {2/2008}, address = {Berlin, Heidelberg, New York}, language = {EN}, publisher = {Springer}, url = {http://www.springerlink.com/content/f672w10742502436/?p=d30247019a4d4df6a6c1ea2a5da5e38d&pi=0} } @InProceedings{Mackay2008, author = {Mackay, Michael and Hutchison, David and Ransburg, Michael and Hellwagner, Hermann}, booktitle = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, title = {Combined Adaptation and Caching of MPEG-4 SVC in Streaming Scenarios}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Hellwagner, Hermann and Timmerer, Christian}, month = apr, pages = {101-104}, publisher = {IEEE}, abstract = {A key objective of the ENTHRONE II Project is the ability to optimise the delivery of multimedia content to a wide group of heterogeneous users. One example of this is in the cooperative deployment of adaptation and caching functionality in the edge network. This hybrid approach makes it possible not only to store content locally, thus minimising the cost incurred through subsequent requests, but also to better serve heterogeneous groups of users by dynamically adapting the content to suit a wide range of terminal devices. In this paper, we describe and evaluate how the cooperative deployment of MPEG-21-based adaptation and caching of MPEG-4 SVC can result in improvements both in the quality of the content received at the user terminal and the resources consumed during the delivery}, isbn13 = {9780769531304}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Combined Adaptation and Caching of MPEG-4 SVC in Streaming Scenarios.pdf}, talktype = {none}, url = {http://www2.computer.org/portal/web/csdl/abs/proceedings/wiamis/2008/3130/00/3130toc.htm} } @InProceedings{Lux2008b, author = {Lux, Mathias}, booktitle = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, title = {Revisiting the Vector Retrieval Model in Context of the MPEG-7 Semantic Description Scheme}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Hellwagner, Hermann and Timmerer, Christian}, month = apr, pages = {134-138}, publisher = {IEEE}, isbn10 = {978-0-7695-3130-4}, language = {EN}, talktype = {none}, url = {http://www2.computer.org/portal/web/csdl/abs/proceedings/wiamis/2008/3130/00/3130toc.htm} } @InProceedings{Lopez2008, author = {López, Fernando and Jannach, Dietmar and Martínez, José M and Timmerer, Christian and Hellwagner, Hermann and García, Narciso}, booktitle = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, title = {Multimedia Adaptation Decisions Modelled as Non-deterministic Operations}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Hellwagner, Hermann and Timmerer, Christian}, month = apr, pages = {46-49}, publisher = {IEEE}, abstract = {This paper describes how a multimedia adaptation framework can automatically decide the sequence of operations to be executed in order to adapt an MPEG-21 Digital Item to the MPEG-21 description of the usage environment in which it will be consumed. The main innovation of this work with respect to previous multimedia adaptation decision models is that in the proposed approach decisions can be made without knowing the exact behaviour of the operations that are going to be executed.}, isbn13 = {9780769531304}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Multimedia Adaptation Decisions Modelled as Non-Deterministic Operations.pdf}, talktype = {none}, url = {http://www2.computer.org/portal/web/csdl/abs/proceedings/wiamis/2008/3130/00/3130toc.htm} } @InProceedings{Lachner2008, author = {Lachner, Janine and Hellwagner, Hermann}, booktitle = {Information Systems and e-Business Technologies (Proc. 2nd International United Information Systems Conference, UNISCON 2008}, title = {Information and Communication Systems for Mobile Emergency Response}, year = {2008}, address = {Berlin, Heidelberg, New York}, editor = {Kaschek, Roland and Kop, Christian and Steinberger, Claudia and Fliedl, Günther}, month = apr, pages = {213-224}, publisher = {Springer}, series = {LNBIP 5}, abstract = {This discussion paper attempts to propose emergency response and disaster management as worthwhile areas of applied research for the informa-tion system community. The typical requirements, entities and activities in-volved in specifically mobile emergency response operations are summarized. Recent research contributions in this area are exemplarily reviewed in order to give a deeper insight into the role and use of mobile information and communi-cation systems. Finally, the major challenges and research needs regarding in-formation systems are summarized, with a view to draw the attention of infor-mation systems researchers to this interesting and important field.}, edition = {1}, isbn10 = {3540789413}, isbn13 = {978-3540789413}, keywords = {Emergency response, disaster management, information systems, mobile information and communication technology}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Information and Communication Systems for Mobile Emergency Response.pdf}, talktype = {none} } @Article{Kuschnig2008, author = {Kuschnig, Robert and Kofler, Ingo and Ransburg, Michael and Hellwagner, Hermann}, journal = {Journal of Visual Communication and Image Representation}, title = {Design options and comparison of in-network H.264/SVC adaptation}, year = {2008}, month = dec, number = {8}, pages = {529-542}, volume = {19}, abstract = {This paper explores design options and evaluates implementations of in-network, RTP/RTSP based adaptation MANEs (Media Aware Network Elements) for H.264/SVC content streaming. The obvious technique to be employed by such an adaptation MANE is to perform SVC specific bitstream extraction or truncation. Another mechanism that can be used is description (metadata) driven, coding format independent adaptation based on generic Bitstream Syntax Descriptions (gBSD), as specified within MPEG-21 Digital Item Adaptation (DIA). Adaptation MANE architectures for both approaches are developed and presented, implemented in end-to-end streaming/adaptation prototype systems, and experimentally evaluated and compared. For the gBSD based solution, open issues like the granularity of bitstream descriptions and of bitstream adaptation, metadata overhead, metadata packetization and transport options, and error resilience in case of metadata losses, are addressed. The experimental results indicate that a simple SVC specific adaptation MANE does clearly outperform the gBSD based adaptation variants. Yet, the conceptual advantages of the description driven approach, like coding format independence and flexibility, may outweigh the performance drawbacks in specific applications.}, address = {Amsterdam}, doi = {10.1016/j.jvcir.2008.07.004}, keywords = {Scalable video coding (H.264/SVC), In-network adaptation, RTP/RTSP MANE, MPEG-21 Digital Item Adaptation (DIA), Generic Bitstream Syntax Description (gBSD)}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/JVCIR08_In-network_H.264-AVC_Adaptation.pdf}, publisher = {Elsevier B.V.} } @InCollection{Kofler2008b, author = {Kofler, Ingo and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Encyclopedia of Multimedia}, publisher = {Springer}, title = {Optimization-based Multimedia Adaptation Decision-Taking}, year = {2008}, address = {New York, USA}, edition = {2}, editor = {Furht, Borko}, month = oct, pages = {699-704}, doi = {10.1007/978-0-387-78414-4_59}, isbn10 = {0387747249}, isbn13 = {978-0387747248}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Encyclopedia_MM_OPT-ADTE_pre.pdf} } @Article{Kofler2008a, author = {Kofler, Ingo and Seidl, Joachim and Timmerer, Christian and Hellwagner, Hermann and Ahmed, Toufik}, journal = {Journal on Signal, Image and Video Processing}, title = {Using MPEG-21 for Cross-layer Multimedia Content Adaptation}, year = {2008}, month = dec, number = {4}, pages = {355-370}, volume = {2}, abstract = {This paper presents a cross-layer model—formulated using interoperable description formats—for the adaptation of scalable H.264/MPEG-4 AVC (i.e., SVC) content in a video streaming system operating on aWireless LANaccess network without QoS mechanisms.SVCcontent adaptation on the server takes place on the application layer using an adaptation process compliant with the MPEG-21 Digital Item Adaptation (DIA) standard, based on input comprised of MPEG-21 DIA descriptions of content and usage environment parameters. The latter descriptions integrate information from different layers, e.g., device characteristics and packet loss rate, in an attempt to increase the interoperability of this cross-layer model, thus making it applicable to other models. For the sake of deriving model parameters, performance measurements from two wireless access point models were taken in account. Throughout the investigation it emerged that the behavior of the system strongly depends on the access point. Therefore, we investigated the use of end-to-end-based rate control algorithms for steering the content adaptation. Simulations of rate adaptation algorithms were subsequently performed, leading to the conclusion that a TFRC-based adaptation technique (TCP-Friendly Rate Control) performs quite well in adapting to limited bandwidth and varying network conditions. In the paper we demonstrate howTFRC-based content adaptation can be realized using MPEG-21 tools.}, address = {London, United Kingdom}, doi = {10.1007/s11760-008-0088-x}, keywords = {Multimedia content adaptation · Cross-layer design · MPEG-21 Digital Item Adaptation · Rate control}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/SIVP08_CrossLayer_Preprint.pdf}, publisher = {Springer} } @InProceedings{Kofler2008, author = {Kofler, Ingo and Prangl, Martin and Kuschnig, Robert and Hellwagner, Hermann}, booktitle = {Proceedings of the 18th International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV)}, title = {An H.264/SVC-based Adaptation Proxy on a WiFi Router}, year = {2008}, address = {New York, NY, USA}, editor = {Wolf, Lars and Griwodz, Carsten}, month = may, pages = {63-68}, publisher = {ACM}, series = {NOSSDAV}, abstract = {Recent advances in video coding technology like the scalable extension of the MPEG-4 AVC/H.264 video coding standard pave the way for computationally cheap adaptation of video content. In this paper we present our work on a lightweight RTSP/RTP proxy that enables in-network stream processing. Based on an off-the-shelf wireless router that runs a Linux-based firmware we demonstrate that the video adaptation can be performed on-the-fly directly on a network device. The paper covers design and implementation details of the proxy as well as a discussion about the actual adaptation of the SVC stream. Based on experimental evaluations we show that our approach can handle a reasonable number of concurrent sessions for a typical home deployment scenario. Furthermore, the paper covers possible applications in which adaptation on the network device can be beneficial.}, doi = {10.1145/1496046.1496061}, keywords = {Multimedia adaptation, in-network adaptation, RTSP, RTP, H.264, scalable video coding}, language = {EN}, location = {Braunschweig, Germany}, pdf = {https://www.itec.aau.at/bib/files/NOSSDAV08_AdaptationProxyRouter-preprint.pdf}, talkdate = {2009.05.29}, talktype = {registered} } @InProceedings{Koepke2008, author = {Köpke, Julius and Tusch, Roland and Hellwagner, Hermann and Böszörmenyi, Laszlo}, booktitle = {Proceedings of the International Conference on Signal Processing and Multimedia Applications}, title = {Context-aware hoarding of Multimedia Content in a large-scale Tour Guide Scenario}, year = {2008}, address = {Setubal}, editor = {Assunção, Pedro and Faria, Sérgio}, month = jul, pages = {15-23}, publisher = {INSTICC Press}, issn = {9789898111609}, language = {EN}, talktype = {none}, url = {http://www.sigmap.org} } @InCollection{Jannach2008, author = {Jannach, Dietmar and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Encyclopedia of Multimedia}, publisher = {Springer}, title = {Knowledge-based Multimedia Adaptation Decision-Taking}, year = {2008}, address = {Berlin, Heidelberg, New York}, edition = {2}, editor = {Furht, Borko}, month = oct, pages = {391-394}, isbn10 = {0387747249}, isbn13 = {978-0387747248}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Encyclopedia_MM_AI-ADTE_pre.pdf} } @InProceedings{Hellwagner2008, author = {Hellwagner, Hermann}, booktitle = {Advances in Multiagent Systems, Robotics and Cybernetics: Theory and Practice (Volume II)}, title = {Challenges toward Adaptive Behavior of Distributed Multimedia Systems}, year = {2008}, address = {Tecumseh}, editor = {Lasker, George E and Pfalzgraf, Jochen}, month = jul, pages = {15-19}, publisher = {The International Institute for Advanced Studies in Systems Research and Cybernetics}, series = {Proceedings of the Symposium on Multiagent Systems, Robotocs and Cybernetics Inter-Symp-2007}, abstract = {The multimedia community is pursuing, among others, the vision of Universal Multimedia Access (UMA). UMA denotes the concept that any multimedia content should be available anywhere, anytime, on any device, tailored to the user's needs and preferences, accessible for the user in a transparent and convenient way. Key to achieving this vision is to realize collaborative adaptive behavior of the involved distributed multi-media system components (server, media-aware net-work elements like proxies or gateways, and clients), based on intense metadata exchange and multimedia content negotiation, adaptation, or personalization. This paper outlines the key challenges and the state of the art in achieving such adaptive behavior. The major challenges have been tackled recently and many of the building blocks of UMA have become or are becoming available from standardization groups, which are instrumental in this area to ensure interop-erable use of the media and metadata items. However, making use of these standards in practical multimedia systems raises additional issues, both of conceptual nature and in terms of implementation. Based on years of contributions to ISO/IEC MPEG standardization efforts and of research work into adaptive multimedia systems, we will give an overview of these challenges, discuss the state of the art, and introduce an emerging principled solution for format-independent multimedia content adaptation.}, edition = {Vol. II}, isbn13 = {9781897233610}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/InterSymp_2007_HH_Adaptive_Behavior_DMS.pdf}, talktype = {none} } @InProceedings{Eberhard2008c, author = {Eberhard, Michael and Celetto, Luca and Timmerer, Christian and Quacchio, Emanuele and Hellwagner, Hermann}, booktitle = {STreaming Day'08 Proceedings}, title = {An Interoperable Streaming Framework for Scalable Video Coding based on MPEG-21}, year = {2008}, address = {Parma}, editor = {Fanucci, Luca and Rovati, Fabrizio and Timmerer, Christian}, month = {sep}, pages = {4}, publisher = {University of Parma}, abstract = {In this paper, an interoperable streaming framework for the adaptation and streaming of scalable multimedia content is presented. The streaming framework’s architecture for Video on Demand (VoD) as well as multicast streaming is presented. The VoD test-bed allows each client to set up a separate streaming session and receive the bitstreams in a quality tailored to the clients requirements, while the multicast test-bed provides a layered scalable multicast to all clients and every client needs to decide which layers to subscribe to. After the description of the architectures, a comparison in terms of performance of the MPEG-21 DIA metadata-based adaptation approach to an SVC-specific adaptation approach is presented. Furthermore, optimizations for both adaptation approaches are presented and the performance improvements due to the optimizations are discussed.}, issn = {9781607029373}, language = {EN}, location = {Parma, Italy}, pdf = {https://www.itec.aau.at/bib/files/Streaming Day'08_Eberhard_StreamingFramework_Paper.pdf}, talkdate = {2008.09.02}, talktype = {registered} } @InProceedings{Eberhard2008b, author = {Eberhard, Michael and Celetto, Luca and Timmerer, Christian and Quacchio, Emanuele and Hellwagner, Hermann and Rovati, Fabrizio S}, booktitle = {Proceedings of the 5th IET Visual Information Engineering Conference Conference (VIE’08)}, title = {An Interoperable Streaming Framework for Scalable Video Coding based on MPEG-21}, year = {2008}, address = {London}, editor = {Izquierdo, Ebroul and Liu, Guizhong}, month = {jul}, pages = {723-728}, publisher = {IET}, abstract = {This paper presents an interoperable framework for the streaming of scalable multimedia content such as Scalable Video Coding (SVC). In particular, the framework’s architecture for both, Video on Demand (VoD) and multicast streaming, is presented. The architecture includes a detailed description of the adaptation engine – conforming to MPEG-21 Digital Item Adaptation – as well as the integration of the adaptation engine into VideoLAN’s VLC media player, which provides the streaming server and client for the framework. Following the description of the architecture, a comparison in terms of performance of the generic MPEG-21 DIA-based adaptation approach, which is utilized by the described demo, versus an SVC-specific adaptation approach is presented and possible further improvements for both approaches are investigated.}, isbn13 = {978-0-86341-914-0}, issn = {0537-9989}, keywords = {Adaptation, MPEG-21 Digital Item Adaptation, Multicasting, Scalable Video Coding, Video on Demand}, language = {EN}, location = {Xi'an, China}, pdf = {https://www.itec.aau.at/bib/files/VIE08_Eberhard.pdf}, talkdate = {2008.07.29}, talktype = {registered} } @InProceedings{Eberhard2008a, author = {Eberhard, Michael and Celetto, Luca and Timmerer, Christian and Quacchio, Emanuele and Hellwagner, Hermann and Rovati, Fabrizio S}, booktitle = {Proceedings of the IEEE International Conference on Multimedia and Expo 2008 (ICME’08)}, title = {An Interoperable Multimedia Delivery Framework for Scalable Video Coding based on MPEG-21 Digital Item Adaptation}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Ostermann, Jörn and Ebrahimi, Touradj}, month = {jun}, pages = {1607-1608}, publisher = {IEEE}, abstract = {In this paper we present an interoperable multimedia delivery framework for scalable video coding based on MPEG-21 Digital Item Adaptation (DIA). In can be used to transmit scalable video contents within heterogeneous usage environments where the properties of the usage environment (e.g., terminal/network capabilities) may change dynamically during the streaming session. The usage environment is signaled by interoperable description formats provided by the DIA standard. Additionally, the adaptation itself is done by exploiting the standard's generic adaptation approach, i.e., independent of the actual coding format. Thus, the overall framework is also applicable for other scalable coding formats.}, issn = {9781424425709}, language = {EN}, location = {Hannover, Germany}, pdf = {https://www.itec.aau.at/bib/files/ICME08_Eberhard.pdf}, talkdate = {2008.06.25}, talktype = {poster} } @InProceedings{Eberhard2008, author = {Eberhard, Michael and Celetto, Luca and Timmerer, Christian and Quacchio, Emanuele and Hellwagner, Hermann}, booktitle = {2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services}, title = {Performance Analysis of Scalable Video Adaptation: Generic versus Specific Approach}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {Hellwagner, Hermann and Timmerer, Christian}, month = {may}, pages = {43-50}, publisher = {IEEE}, abstract = {This paper provides a performance analysis of adaptation approaches designed for scalable media resources. In particular, we investigate the streaming of media resources compliant to the Scalable Video Coding (SVC) extensions of Advanced Video Coding (AVC)within heterogeneous environments, i.e., terminals and networks with different capabilities. Therefore, we have developed a test-bed in order to analyze two different approaches for the adaptation of scalable media resources, namely a generic approach that is applicable independently of the actual scalable coding format used and a specific approach especially built for SVC.The results show that if adaptation is required the generic approach clearly outperforms the approach specifically built for SVC}, isbn10 = {076953130X}, isbn13 = {978-0769531304}, language = {EN}, location = {Klagenfurt, Austria}, pdf = {https://www.itec.aau.at/bib/files/wiamis08_eberhard.pdf}, talkdate = {2008.05.09}, talktype = {registered} } @InProceedings{Bolla2008, author = {Bolla, Raffaele and Repetto, Matteo and Chessa, Stefano and Furfari, Francecso and Zutter, Saar De and Walle, Rik Van de and Reiterer, Bernhard and Hellwagner, Hermann and Asbach, Mark and Wien, Mathias}, booktitle = {13th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA08)}, title = {A Context-Aware Architecture for QoS and Transcoding Management of Multimedia Streams in Smart Homes}, year = {2008}, address = {Los Alamitos, CA, USA}, editor = {IEEE, Industrial Electronics Society}, month = sep, pages = {1354-1361}, publisher = {IEEE}, abstract = {Current trends in smart homes suggest that several multimedia services will soon converge towards common standards and platforms. However this rapid evolution gives rise to several issues related to the management of a large number of multimedia streams in the home communication infrastructure. An issue of particular relevance is how a context acquisition system can be used to support the management of such a large number of streams with respect to the Quality of Service (QoS), to their adaptation to the available bandwidth or to the capacity of the involved devices, and to their migration and adaptation driven by the users' needs that are implicitly or explicitly notified to the system. Under this scenario this paper describes the experience of the INTERMEDIA project in the exploitation of context information to support QoS, migration, and adaptation of multimedia streams.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/04638575.pdf}, talktype = {none} } @InProceedings{VanDeursen2007, author = {Deursen, Davy Van and Bruyne, Sarah De and Lancker, Wim Van and Neve, Wesley De and Schrijver, Davy De and Hellwagner, Hermann and Walle, Rik Van de}, booktitle = {IEEE International Symposium on Multimedia 2007 (ISM2007)}, title = {MuMiVA: A Multimedia Delivery Platform using Format-agnostic, XML-driven Content Adaptation}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {Bulterman, Dick and Mori, Kinji and Tsai, Jeffrey J P}, month = dec, pages = {131-138}, publisher = {IEEE}, abstract = {Due to the increasing heterogeneity in the current multimedia landscape, the delivery of multimedia content has become an important issue today. This heterogeneity is not only reflected by a plethora of different usage environments, but also by the presence of multiple (scalable) coding formats. Therefore, format-independent adaptation engines have to be used within a multimedia delivery platform, which are able to adapt the multimedia content according to a certain usage environment, independent of the underlying coding format of the content. By relying on automatically created textual descriptions of the highlevel syntax of binary media resources, a format-independent adaptation engine can be build. MPEG-21 generic Bitstream Syntax Schema (gBS Schema) is a tool that is part of the MPEG-21 Multimedia Framework. It enables the use of generic Bitstream Syntax Descriptions (gBSDs), i.e., textual descriptions in XML, to steer the adaptation of a binary media resource, using format-independent adaptation logic. In this paper, we address the design and performance evaluation of a multimedia delivery platform that relies on gBS Schema-driven adaptation engines. This platform is called MuMiVA; it is a fully integrated, extensible platform for multimedia delivery in heterogeneous usage environments, using streaming technologies. To demonstrate the flexibility of our multimedia delivery platform, we discuss the functioning of two different applications (i.e., exploitation of temporal scalability and shot selection) applied to two different coding formats (i.e., MPEG-4 Visual and H.264/AVC). Keywords— Content adaptation, Content delivery, MPEG-21 gBS Schema, XML transformations.}, isbn10 = {0769530583}, isbn13 = {978-0769530581}, keywords = {0769530583}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/MuMiVA.pdf}, talktype = {none}, url = {http://www.ism2007.ncu.edu.tw/} } @InProceedings{Ransburg2007a, author = {Ransburg, Michael and Timmerer, Christian and Hellwagner, Hermann and Devillers, Sylvain}, booktitle = {WIAMIS 2007}, title = {Design and Evaluation of a Metadata-Driven Adaptation Node}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {Kompatsiaris, Yiannis and Avrithis, Yannis}, month = jun, pages = {4}, publisher = {IEEE}, abstract = {MPEG-21 Digital Item Adaptation (DIA) allows for a media codec agnostic multimedia adaptation approach which enables the implementation of generic adaptation engines. However, DIA is optimized for static, server-based adaptation. In this paper we introduce novel mechanisms to extend the DIA approach towards dynamic and distributed scenarios. This facilitates the placement of generic adaptation nodes which perform media codec agnostic and dynamic adaptation anywhere along the content delivery path. To validate our work we implemented such an adaptation node and evaluate its performance.}, issn = {0-7695-2818-X}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Design and Evaluation of a Metadata-Driven Adaptation Node.pdf}, talktype = {none}, url = {http://www.computer.org/proceedings/} } @InProceedings{Ransburg2007, author = {Ransburg, Michael and Devillers, Sylvain and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Datenbanksysteme in Business, Technologie und Web (BTW 2007)}, title = {Processing and Delivery of Multimedia Metadata for Multimedia Content Streaming}, year = {2007}, address = {Aachen}, editor = {Jarke, Matthias and Seidl, Thomas and Quix, Christoph and Kensche, David and Conrad, St and Rahm, E and Klamma, Ralf and Kosch, Harald and Granitzer, Michael and Apel, S and Rosenmüller, M and Saake, Gunter and Spinczyk, Olaf}, month = mar, pages = {117-138}, publisher = {Verlag Mainz}, abstract = {Today’s increasing variety of media data results in a great diversity of XMLbased metadata, which describes the media data on semantic or syntactic levels, in order to make it more accessible to the user. This metadata can be of considerable size, which leads to problems in streaming scenarios. Other than media data, XML metadata has no concept of “samples”, thus inhibiting streamed (and timed) processing, which is natural for media data. In order to address the challenges and requirements resulting from this situation, the concept of streaming instructions is introduced. In particular, streaming instructions address the problem of fragmenting metadata, associating media segments and metadata fragments, and streaming and processing them in a synchronized manner. This is achieved by enriching the metadata with additional attributes to describe media and XML properties. Alternatively, a style sheet approach provides the opportunity to dynamically set such streaming properties without actually modifying the XML description.}, issn = {3861309297}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Processing and Delivery of Multimedia Metadata for Multimedia Content Streaming.pdf}, talktype = {none} } @InProceedings{Prangl2007b, author = {Prangl, Martin and Bachlechner, Roland and Hellwagner, Hermann}, booktitle = {2007 IEEE International Conference on Multimedia and Expo (ICME 2007)}, title = {A hybrid recommender strategy for personalized utility-based cross-modal multimedia adaptation}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {Zhuang, Xinhua and Gao, Wen}, month = jul, pages = {1707-1710}, publisher = {IEEE}, abstract = {Enabling transparent and augmented use of multimedia content across a wide range of networks and devices is still a challenging task within the multimedia research community. Within multimedia frameworks, content adaptation is the core concept to overcome this issue. Most media adaptation engines targeting Universal Multimedia Access (UMA) scale the content w.r.t. terminal capabilities and network resource constraints and do not sufficiently consider user preferences. This paper focuses on a hybrid recommender technique for configuring a cross-modal utility model that guides adaptation of multimedia content. This approach additionally considers the user environment as well as demographic user data which leads to a personalized and increased multimedia experience. Based on a related adaptation decision technique we show how it is possible to offer a personalized adaptation for the individual user. We present a detailed evaluation of the approach based on results earned by subjective tests.}, issn = {1-4244-1017-7}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A hybrid recommender strategy for personalized utility-based cross-modal multimedia adaptation.pdf}, talktype = {none} } @Article{Prangl2007a, author = {Prangl, Martin and Szkaliczki, Tibor and Hellwagner, Hermann}, journal = {IEEE Transactions on Circuits and Systems for Video Technology}, title = {A Framework for Utility-Based Multimedia Adaptation}, year = {2007}, issn = {1051-8215}, month = jun, number = {6}, pages = {719-728}, volume = {17/2007}, abstract = {Content adaptation is an important issue of multimedia frameworks in order to achieve universal multimedia access (UMA), i.e., to enable consumption of multimedia content independently of the given resource limitations, terminal capabilities, and user preferences. The digital item adaptation (DIA) standard, one of the core specifications of the MPEG-21 framework, supports content adaptation considering a wide range of networks, devices, and user preferences. Most adaptive multimedia frameworks targeting the UMA vision do not consider utility aspects in their adaptation decisions. This paper focuses on a generic semantic-based audio–visual utility model for DIA that aims to enhance the multimedia experience for the user. Our proposed model is able to take the semantics and the perceptual features of the content as well as the users' specific utility aspects into account. Based on a detailed analysis of these constraints, we will show how the model reacts on individual input data. For choosing the best adaptation decision considering resource limitations on client and server sides as well as network characteristics, we evaluate four algorithms for performing this adaptation decision taking task. We will discuss results according to some use case scenarios.}, address = {Los Alamitos, CA, USA}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A Framework for Utility-Based Multimedia Adaptation.pdf}, publisher = {IEEE} } @InProceedings{Prangl2007, author = {Prangl, Martin and Hellwagner, Hermann}, booktitle = {World of Wireless, Mobile and Multimedia Networks, 2007. WoWMoM 2007}, title = {A framework for personalized utility-aware IP-based multimedia consumption}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {Fleury, Eric and Karl, Holger}, month = {jan}, pages = {1-3}, publisher = {IEEE}, abstract = {Providing transparent and augmented use of multimedia content across a wide range of networks and devices is still a challenging task within the multimedia research community. Multimedia adaptation was figured out as a core concept to overcome this issue. Most multimedia adaptation engines for providing Universal Multimedia Access (UMA) scale the content under consideration of terminal capabilities and resource constraints but do not really consider individual user preferences. This paper introduces an adaptive multimedia framework which offers the user a personalized content variation for satisfying his/her individual utility preferences.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A framework for personalized utility-aware ip-based multimedia consumption.pdf}, talktype = {none}, url = {http://www.tml.tkk.fi/IEEE-wowmom/index.html} } @Book{Mylonas2007, author = {Mylonas, Phivos and Wallace, Manolis and Angelides, Marios C and Hellwagner, Hermann and Agius, Harry}, publisher = {IEEE}, title = {Second International Workshop on Semantic Media Adaptation and Personalization (SMAP 2007)}, year = {2007}, address = {Los Alamitos, CA, USA}, month = dec, isbn10 = {0769530400}, isbn13 = {978-0769530406}, language = {EN}, pages = {269}, url = {http://www.smap2007.org/} } @InProceedings{Lachner2007, author = {Lachner, Janine and Lorenz, Andreas and Reiterer, Bernhard and Zimmermann, Andreas and Hellwagner, Hermann}, booktitle = {Second International Workshop on Semantic Media Adaptation and Personalization (SMAP 2007)}, title = {Challenges toward User-centric Multimedia}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {Mylonas, Phivos and Wallace, Manolis and Angelides, Marios C}, month = sep, pages = {159-164}, publisher = {IEEE}, abstract = {Currently, much research aims at coping with the shortcomings in multimedia consumption that may exist in a user's current context, e.g., due to the absence of appropriate devices at many locations, a lack of capabilities of mobile devices, restricted access to content, or non-personalized user interfaces. Recently, solutions to specific problems have been emerging, e.g., wireless access to multimedia repositories over standardized interfaces; however, due to usability restrictions the user has to spend much effort to or is even incapable of fulfilling his/her demands. The vision of user-centric multimedia places the user in the center of multimedia services to support his/her multimedia consumption intelligently, dealing with the aforementioned issues while minimizing required work. Essential features of such a vision are comprehensive context awareness, personalized user interfaces, and multimedia content adaptation. These aspects are addressed in this paper as major challenges toward a user-centric multimedia framework.}, isbn10 = {0769430400}, isbn13 = {9780769530406}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Challenges toward User-centric Multimedia.pdf}, talktype = {none}, url = {http://www.smap2007.org/} } @InProceedings{Kropfberger2007, author = {Kropfberger, Michael and Tusch, Roland and Jakab, Michael and Köpke, Julius and Ofner, Michael and Hellwagner, Hermann and Böszörmenyi, Laszlo}, booktitle = {Proceedings of the 3rd International Conference on Web Information Systems and Technologies (WEBIST '07)}, title = {A Multimedia-Based Guidance System for various Consumer Devices}, year = {2007}, address = {Setubal, Portugal}, editor = {Filipe, Joaquim and Cordeiro, José}, month = mar, pages = {83-90}, publisher = {INSTICC Press}, abstract = {This paper introduces aWeb-based guidance system which supports optimized presentations of sights or exhibited objects on different types of available stationary and mobile consumer devices, possibly running different operating systems. This is accomplished by adapting both the objects’ content, as well as their presentation to the current usage context. Content thereby may be encoded in different presentation formats like video, audio, image, and marked-up text. The usage context embraces a set of properties describing the current usage environment of the guide. This includes, for example, the consumer device’s capabilities, its current location, and the user’s preferences. Both, the content adaptation and presentation services are based on standardWeb technologies for increased interoperability. Finally, the guidance system is augmented with a Web-based content management and a statistics module, which enable for remote content administration and usage evaluations, respectively.}, isbn13 = {978-3-540-68257-8}, keywords = {Multimedia-based guide for stationary and mobile devices, context-awareness, content adaptation, presentation adaptation, content management.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A multimedia-based guidance system for various consumer devices.pdf}, talktype = {none}, url = {http://www.webist.org/} } @InProceedings{Kofler2007a, author = {Kofler, Ingo and Timmerer, Christian and Ahmed, Toufik and Hellwagner, Hermann}, booktitle = {Proceedings of the Second International Workshop on Semantic Media Adaptation and Personalization (SMAP)}, title = {Towards MPEG-21-based Cross-layer Multimedia Content Adaptation}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {Mylonas, Phivos and Wallace, Manolis and Angelides, Marios C}, month = dec, pages = {3-8}, publisher = {IEEE}, series = {SMAP}, abstract = {The adaptation of multimedia resources is a common method to enable the transport and consumption of audio-visual content in constrained environments. An important aspect in this field is adaptation decision-taking, which aims to find adaptation parameters that maximize the quality for the consumer while considering the constraints of the networks and terminals involved. In this paper we focus on improving the adaptation of audio-visual content by maximizing the perceived quality. This can be realized by using a multimedia quality model and content-related metadata. We present an approach to derive this content-related metadata from subjective tests and use it for adaptation decision-taking within the MPEG-21 multimedia framework.}, doi = {10.1109/SMAP.2007.34}, isbn10 = {0769530400}, isbn13 = {978-0769530406}, language = {EN}, location = {London, United Kingdom}, pdf = {https://www.itec.aau.at/bib/files/MPEG-21XL_SMAP2007.pdf}, talkdate = {2009.05.29}, talktype = {registered} } @InProceedings{Jakab2007, author = {Jakab, Michael and Kropfberger, Michael and Ofner, Michael and Tusch, Roland and Hellwagner, Hermann and Böszörmenyi, Laszlo}, booktitle = {Proceedings of the 15th Euromicro Conference on Parallel, Distributed and Network-based Processing}, title = {Metadata Integration and Media Transcoding in Universal-Plug-and-Play (UPnP) Enabled Networks}, year = {2007}, address = {Los Alamitos, CA, USA}, editor = {D'Ambra, Pasqua and Guarracino, Mario R}, month = jan, pages = {363 - 369}, publisher = {IEEE}, abstract = {Universal Plug and Play (UPnP) is a widely accepted standard for automatically detecting devices and services in a local area network as well as for describing and controlling them. In order to deal with multimedia devices and especially content, in 2002 the UPnP-AV standard definition was released. It defines device and service descriptions for Media Servers and Renderers. Thereby, the Media Server’s Content Directory Service allows an easy management and the exchange of metadata about the provided media data. Media content became browsable by semantic meta information about it. There are still two major drawbacks of UPnP-AV, which make its usage in real world multimedia communication scenarios very difficult. First, searching for similar content on distributed Media Servers with a huge number of media files is not economically possible. Second, the media content must be consumed by Renderers as provided by the Servers, independently of their terminal capabilities and network connections. In order to deal with these two drawbacks, this work proposes a novel approach of metadata integration and media transcoding in UPnP networks. First, the Media Server is extended by a Control Point which offers discovery of other Media Servers and fetches metadata from their Content Directories. Furthermore, it integrates the gathered information in its own Content Directory. Control Points are then able to query this Integrating Media Server for a desired content, and get a network-complete search result. Second, terminal and network capabilities of the Render-ers are taken into account in order to transcode and transmit the content in a suitable way for the consuming device. These two approaches of metadata integration and media data adaptation enable searchable logical views on tailored multimedia content in UPnP-AV networks.}, issn = {1066-6192}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Universal-Plug-and-Play.pdf}, talktype = {none} } @Article{Boeszoermenyi2007a, author = {Böszörmenyi, Laszlo and Hellwagner, Hermann and Schojer, Peter}, journal = {Multimedia Systems}, title = {Metadata-driven optimal transcoding in a multimedia proxy}, year = {2007}, month = jul, number = {Issue 1}, pages = {51-68}, volume = {Vol. 13}, abstract = {An adaptive multimedia proxy is presented which provides (1) caching, (2) filtering, and (3) media gateway functionalities. The proxy can perform media adaptation on its own, either relying on layered coding or using transcoding mainly in the decompressed domain. A cost model is presented which incorporates user requirements, terminal capabilities, and video variations in one formula. Based on this model, the proxy acts as a general broker of different user requirements and of different video variations. This is a first step towards What You Need is What YouGet (WYNIWYG) video services, which deliver videos to users in exactly the quality they need and are willing to pay for. The MPEG-7 and MPEG-21 standards enable this in an interoperable way. A detailed evaluation based on a series of simulation runs is provided.}, address = {Berlin, Heidelberg, New York}, doi = {9780769530406}, keywords = {Video proxy · Video caching · Media gateway · Media adaptation · Metadata · MPEG-7 · MPEG-21 · Cache replacement}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Metadata-driven optimal transcoding in a multimedia proxy.pdf}, publisher = {Springer} } @InProceedings{Timmerer2006, author = {Timmerer, Christian and DeMartini, Thomas and Hellwagner, Hermann}, booktitle = {D A CH Security 2006}, title = {The MPEG-21 Multimedia Framework: Conversions and Permissions}, year = {2006}, address = {Düsseldorf}, editor = {Horster, Patrick}, month = mar, pages = {225-235}, publisher = {IT Security \& IT Management}, abstract = {In the area of multimedia computing and communication, one of the major objectives currently being pursued is Universal Multimedia Access (UMA), i.e., enabling users to transparently access any kind of content from anywhere, anytime, with any device. In the course of the MPEG-21 (Multimedia Framework) activities, the ISO/IEC MPEG standardization group has created essential building blocks toward this goal, mainly metadata standards. Two of them are worth noting here: (1) the Digital Item Adaptation (DIA) specification, including normative vocabulary and formats to describe the multimedia consumption context (device, network, natural environment characteristics, user preferences) and to steer media adaptation operations required for UMA; (2) the Rights Expression Language (REL) and Rights Data Dictionary (RDD) specifications, providing terms and a language to express permissions on the usage of the media (who, how, what, under which conditions). In this paper, we describe a recent MPEG-21 DIA Amendment in this area, specifying description formats for: (1) multimedia conversion capabilities, which tool or service providers may use to normatively specify the media adaptation (conversion) capabilities of their tools or services, respectively; (2) permissions and conditions for multimedia conversions, which can be utilized by content providers to determine which adaptations (changes) are permitted on their contents under what conditions. The latter description format embeds media adaptation descriptions into rights expressions, filling a gap between DIA and REL/RDD. In the paper, a use case illustrating a complex UMA scenario justifies the need for these descriptions. Exemplary conversions and permissions descriptions that apply to this use case as well as detailed explanations will be given in the main portion of the paper.}, issn = {3-00-018166-0}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/The MPEG-21 multimedia framework.pdf}, talktype = {none} } @InProceedings{Schojer2006a, author = {Schojer, Peter and Böszörmenyi, Laszlo and Hellwagner, Hermann}, booktitle = {Multimedia Computing and Networking 2006}, title = {QBIX-G- A Transcoding Multimedia Proxy}, year = {2006}, address = {San Jose}, editor = {Chandra, Surendar and Griwodz, Carsten}, month = jan, pages = {60710C-1 - 60710C-16}, publisher = {SPIE}, abstract = {An adaptive multimedia proxy is presented which provides (1) caching, (2) filtering, and (3) media gateway functionalities. The proxy can perform media adaptation on its own, either relying on layered coding or using transcoding and transrating in the decompressed domain. A cost model is presented which incorporates (1) user requirements, (2) terminal capabilities, and (3) video variations in one formula. Based on this model, the proxy acts as a general broker of different user requirements and of different video variations. This is a first step towards “What You Need is What You Get” (WYNIWYG) video services, which deliver videos to users in exactly that quality they need and are willing to pay for. The MPEG-7 and MPEG-21 standards enable this in an interoperable way. A detailed evaluation based on a series of simulation runs is provided. Based on the simulation results, the algorithms were integrated into our “Quality Based Intelligent Proxy”, the evaluation of which is in progress.}, issn = {0-8194-6111-3}, language = {EN}, talktype = {none} } @TechReport{Schojer2006, author = {Schojer, Peter and Böszörmenyi, Laszlo and Hellwagner, Hermann}, institution = {Institute of Information Technology ({ITEC}), Klagenfurt University}, title = {QBIX-G-A Transcoding Multimedia Proxy}, year = {2006}, address = {Klagenfurt, Austria}, month = {jan}, number = {TR/ITEC/05/2.11}, abstract = {An adaptive multimedia proxy is presented which provides (1) caching, (2) filtering, and (3) media gateway functionalities. The proxy can perform media adaptation on its own, either relying on layered coding or using transcoding in the decompressed domain. A cost model is presented which incorporates user requirements, terminal capabilities, and video variations in one formula. Based on this model, the proxy acts as a general broker of different user requirements and of different video variations. This is a first step towards What You Need is What You Get (WYNIWYG) video services, which deliver videos to users in exactly the quality they need and are willing to pay for. The MPEG-7 and MPEG-21 standards enable this in an interoperable way. A detailed evaluation based on a series of simulation runs is provided.}, language = {EN}, pages = {24} } @InProceedings{Santner2006, author = {Santner, Martin and Tusch, Roland and Kropfberger, Michael and Böszörmenyi, Laszlo and Hellwagner, Hermann}, booktitle = {D•A•CH Mobility 2006}, title = {Ein Ortserkennungssystem für mobile Touristenführer}, year = {2006}, address = {Ottobrunn, München, Deutschland}, editor = {Horster, Patrick}, month = oct, pages = {84-98}, publisher = {IT Security \& IT Management}, abstract = {- Location-Based Services - Ortserkennungstechnologien - Ortserkennungsmiddleware - Integration in mobile Anwendung - Automatisiertes Führungssystem.}, issn = {3000196358}, language = {DE}, talktype = {none} } @InProceedings{Ransburg2006, author = {Ransburg, Michael and Cazoulat, Renaud and Pellan, Benoit and Concolato, Cyril and De Zutter, Saar and Poppe, Chris and Hutter, Andreas and Hellwagner, Hermann and Van de Walle, Rik}, booktitle = {Proc. of the European Symposium on Mobile Media Delivery (EuMob 2006)}, title = {Dynamic and Distributed Adaptation of Scalable Multimedia Content in a Context-Aware Environment}, year = {2006}, address = {Alghero, Italy}, editor = {EuMob, 2006}, month = sep, pages = {1-5}, publisher = {--}, abstract = {The seamless access to rich multimedia content on any device and over any network, usually known as Universal Multimedia Access, requires interoperable description tools and adaptation techniques to be developed. To address this, MPEG-21 introduces an adaptation framework, which provides several mechanisms for making adaptation decisions according to usage environment and adapting multimedia contents in a coding format independent way. This paper gives an overview of the European FP6 project DANAE which not only implements and extends the existing MPEG-21 adaptation mechanisms but also kicked off several new standardization activities in the area of dynamic and distributed adaptation and resource conversion. MPEG-21 DIP enables static stream selection which is a first step in a series of adaptations. The existing BSD-based adaptation mechanisms enable the efficient implementation of generic adaptation engines, which can be used for existing and future coding formats. These mechanisms were extended to enable dynamic and distributed adaptation. Alternatively to the BSD-based adaptation, resource conversion was investigated which does not rely on scalable media and allows adaptations at the scene level.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Dynamic and Distributed Adaptation of Scalable Multimedia Content in a Context-Aware Environment.pdf}, talktype = {none} } @InProceedings{Prangl2006d, author = {Prangl, Martin and Hellwagner, Hermann and Szkaliczki, Tibor}, booktitle = {Proceedings oft the IEEE International Conference on Multimedia and Expo (ICME)}, title = {Fast adaptation decision taking for cross-modal multimedia content adaptation}, year = {2006}, address = {Toronto, Canada}, editor = {Ling, Guan and Hong-Jiang, Zhang}, month = jul, pages = {137-140}, publisher = {IEEE Press}, abstract = {In order to enable transparent and convenient use of multimedia content across a wide range of networks and devices, content adaptation is an important issue within multimedia frameworks. The so called Digital Item Adaptation (DIA) standard is one of the core concepts of the MPEG-21 framework that will support the adaptation of multimedia resources according to device capabilities, underlying network characteristics, and user preferences. Most multimedia adaptation engines for providing Universal Multimedia Access (UMA) scale the content with respect to terminal capabilities and resource constraints. This paper focuses on the cross-modal adaptation decision taking process considering the user environment and terminal capabilities as well as resource limitations on the server, network, and client side. This approach represents a step toward increased Universal Multimedia Experience (UME). Based on four different algorithms for solving this optimization process, we present an evaluation of results gained by running their implementations on different test networks.}, issn = {1-4244-0367-7}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Fast adaptation decision taking for cross-modal multimedia content adaptation.pdf}, talktype = {none} } @InProceedings{Prangl2006c, author = {Prangl, Martin and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings ELMAR 2006}, title = {Real-time DVB based MPEG-21 Digital Item Adaptation for live Universal Multimedia Access}, year = {2006}, address = {Zadar}, editor = {Grgic, Mislav and Grgic, Sonja}, month = jun, pages = {297-300}, publisher = {Croatian Society Electronics in Marine - ELMAR, Zadar}, abstract = {In order to enable transparent and augmented use of multimedia content across a wide range of networks and devices, content adaptation is an important issue within multimedia frameworks. In this paper, we present a prototype application that receives Digital Video Broadcast (DVB) TV streams on a PC, transcodes the streams on the fly according to the individual User requirements and packs the adapted content together with available metadata into a standard compliant MPEG-21 Digital Item (DI). In this form, the framework enables the live Universal Multimedia Access (UMA) scenario where the DVB content can be transparently accessed by clients such as PCs and PDAs, anytime and anywhere.}, issn = {13342630}, keywords = {DVB, MEPG-2, MPEG-4, MPEG-7, MPEG-21, Digital Items, metadata}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Real-time DVB-based MPEG-21 Digital Item Adaptation.pdf}, talktype = {none} } @InProceedings{Prangl2006b, author = {Prangl, Martin and Hellwagner, Hermann and Szkaliczki, Tibor}, booktitle = {Proceedings of the 7th International Workshop on Image Analysis for Multimedia Services (WIAMIS)}, title = {A Semantic-based Multi-modal Utility Approach For Multimedia Adaptation}, year = {2006}, address = {Incheon, Korea}, editor = {Ebroul, Izquierdo and Hyoung Joon, Kim}, month = apr, pages = {67-70}, publisher = {WIAMIS Eigenverlag}, abstract = {Content adaptation is an important issue of multimedia frameworks in order to achieve Universal Multimedia Access (UMA), that is, to enable consumption of individual multimedia content independently of the given resource limitations, terminal capabilities and user preferences. The Digital Item Adaptation (DIA) standard, one of the core specifications of the MPEG-21 framework, supports content adaptation considering a wide range of networks, devices and user preferences. Most adaptive multimedia frameworks enabling this UMA do not consider utility aspects in their adaptation decisions. This paper focuses on a generic multi-modal utility model for DIA, enabling increased multimedia experience to the client. Our proposed model is able to take the semantic and the perceptual features of the content as well as the clients individual utility aspects into consideration. Based on a detailed analysis of these constraints we will show how the model reacts on individual input data. Finally we will discuss results of the multi-modal decision taking process according to a few use case scenarios as well.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A Semantic-based Multi-modal Utility Approach For Multimedia Adaptation.pdf}, talktype = {none} } @InProceedings{Prangl2006a, author = {Prangl, Martin and Hellwagner, Hermann and Bischof, Horst and Szkaliczki, Tibor}, booktitle = {Proceedings of the SPIE Symposium on Medical Imaging 2006}, title = {Realtime automatic metal extraction of medical x-ray images for contrast improvement}, year = {2006}, address = {San Diego}, editor = {Reinhardt, Joseph M and Pluim, Josien P W}, month = mar, pages = {8}, publisher = {SPIE}, series = {Vol. 6144}, abstract = {This paper focuses on an approach for real-time metal extraction of x-ray images taken from modernx-ray machines like C-arms. Such machines are used for vessel diagnostics, surgical interventions, as well as cardiology, neurology and orthopedic examinations. They are very fast in taking images from different angles. For this reason, manual adjustment of contrast is infeasible and automatic adjustment algorithms have been applied to try to select the optimal radiation dose for contrast adjustment. Problems occur when metallic objects, e.g., a prosthesis or a screw, are in the absorption area of interest. In this case, the automatic adjustment mostly fails because the dark, metallic objects lead the algorithm to overdose the x-ray tube. This outshining effect results in overexposed images and bad contrast. To overcome this limitation, metallic objects have to be detected and extracted from images that are taken as input for the adjustment algorithm.In this paper, we present a real-time solution for extracting metallic objects of x-ray images. We will explore the characteristic features of metallic objects in x-ray images and their distinction from bone fragments which form the basis to find a successful way for object segmentation and classification. Subsequently, we will present our edge based real-time approach for successful and fast automatic segmentation and classification of metallic objects. Finally, experimental results on the effectiveness and performance of our approach based on a vast amount of input image data sets will be presented.}, isbn13 = {9780819464231}, keywords = {Pattern recognition, Segmentation, Medical imaging, X-Ray, Artefact-Segmentation}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Realtime automatic metal extraction of medical x-ray images for contrasst improvement.pdf}, talktype = {none} } @InProceedings{Kofler2006a, author = {Kofler, Ingo and Hellwagner, Hermann}, booktitle = {Proceedings of the 2nd International Conference on Automated Production of Cross Media Content for Multi-channel Distribution ({AXMEDIS})}, title = {MPEG-21-based Cross-Resource Adaptation Decision-Taking}, year = {2006}, address = {Firenze, Italy}, editor = {Kia, Ng and Badii, Atta and Bellini, Pierfrancesco}, month = dec, pages = {207-214}, publisher = {Firenze University Press}, series = {AXMEDIS}, abstract = {The adaptation of multimedia resources is a common method to enable the transport and consumption of audio-visual content in constrained environments. An important aspect in this field is adaptation decision-taking, which aims to find adaptation parameters that maximize the quality for the consumer while considering the constraints of the networks and terminals involved. In this paper we focus on improving the adaptation of audio-visual content by maximizing the perceived quality. This can be realized by using a multimedia quality model and content-related metadata. We present an approach to derive this content-related metadata from subjective tests and use it for adaptation decision-taking within the MPEG-21 multimedia framework.}, language = {EN}, location = {Leeds, United Kingdom}, pdf = {https://www.itec.aau.at/bib/files/AXMEDIS2006MPEG21CrossResourceAdaptationDecisionTaking.pdf}, talkdate = {2006.12.13}, talktype = {registered} } @Article{Jannach2006, author = {Jannach, Dietmar and Leopold, Klaus and Timmerer, Christian and Hellwagner, Hermann}, journal = {Applied Intelligence - Special Issue: Innovations in Applied Artificial Intelligence}, title = {A Knowledge-Based Framework For Multimedia Adaptation}, year = {2006}, issn = {0924-669X}, month = apr, number = {No. 2}, pages = {109-125}, volume = {Vol. 24}, abstract = {Abstract Personalized delivery of multimedia content over the Internet opens new business perspectives for future multimedia applications and thus plays an important role in the ongoing MPEG-7 and MPEG-21 multimedia standardization efforts. Based on these standards, next-generation multimedia services will be able to automatically prepare the digital content before delivery according to the client’s device capabilities, the network conditions, or even the user’s content preferences. However, these services will have to deal with a variety of different end user devices, media formats, as well as with additional metadata when adapting the original media resources. In parallel, an increasing number of commercial or open-source media transformation tools will be available, capable of exploiting such descriptive metadata or dealing with new media formats; thus it is not realistic that a single tool will support all possible transformations. In this paper, we present a novel, fully knowledge-based approach for building such multimedia adaptation services, addressing the above mentioned issues of openness, extensibility, and concordance with existing and upcoming standards. In our approach, the original media is transformed in multiple adaptation steps performed by an extensible set of external tools, where the construction of adequate adaptation sequences is solved in an Artificial Intelligence planning process. The interoperability issue is addressed by exploiting standardized Semantic Web Services technology. This technology allows us to express tool capabilities and execution semantics in a declarative and well-defined form. In this context, existing multimedia standards serve as a shared domain ontology. The presented approach was implemented and successfully evaluated in an official ISO/IEC MPEG (Moving Picture Experts Group) Core Experiment and is currently under further evaluation by the standardization body.}, address = {Berlin, Heidelberg, New York}, language = {EN}, publisher = {Springer}, url = {http://www.springerlink.com/content/w745246635772v97/} } @Article{DeSutter2006a, author = {De Sutter, Robbie and Lerouge, Sam and De Neve, Peter and Timmerer, Christian and Hellwagner, Hermann and Van de Walle, Rik}, journal = {Multimedia Systems}, title = {Comparison of XML serializations: cost benefits versus complexity}, year = {2006}, month = oct, number = {Nr. 2}, pages = {101-115}, volume = {Vol. 12}, abstract = {More and more data are structured, stored, and sent over a networ using the Extensible Markup Language (XML) language. There are, however, concerns about the verbosity of XML in such a way that it may restrain further adoption of the language, especially when exchanging XML-based data over heterogeneous networks, and when it is used within constrained (mobile) devices. Therefore, alternative (binary) serialization formats of the XML data become relevant in order to reduce this overhead. However, using binary-encoded XML should not introduce interoperability issues with existing applications nor add additional complexity to new applications. On top of that, it should have a clear cost reduction over the current plain-text serialization format. A first technology is developed within the ISO/IEC Moving Picture Experts Group, namely the Binary MPEG Format for XML. It provides good compression efficiency, ability to (partially) update existingXMLtrees, and facilitates random access into, and manipulation of, the binary-encoded bit stream. Another technique is based on the Abstract Syntax Notation One specification with the Packed Encoding Rules created by the ITU-T. This paper evaluates both techniques as alternative XML serialization formats and introduces a solution for the interoperability concerns. This solution and the alternative serialization formats are validated against two real-life use cases in terms of processing speed and cost reduction. The efficiency of the alternative serialization formats are compared to a classic plain text compression technique, in particular ZIP compression.}, address = {Berlin, Heidelberg, New York}, doi = {10.1007/s00530-006-0044-y}, keywords = {XML serialization formats · MPEG-B · ASN.1 · Information encoding · Data interchange formats · Multimedia applications}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Comparison of XML serializations_cost benefits versus complexity.pdf}, publisher = {Springer} } @Article{DeSutter2006, author = {De Sutter, Robbie and Lerouge, Sam and De Neve, Peter and Timmerer, Christian and Hellwagner, Hermann and and Van de Walle, Rik}, journal = {ACM Multimedia Systems}, title = {Comparison of XML serializations: cost benefit vs. complexity}, year = {2006}, issn = {0942-4962}, month = aug, number = {No 1}, pages = {1-15}, volume = {Vol 12}, abstract = {More and more data are structured, stored, and sent over a networ using the Extensible Markup Language (XML) language. There are, however, concerns about the verbosity of XML in such a way that it may restrain further adoption of the language, especially when exchanging XML-based data over heterogeneous networks, and when it is used within constrained (mobile) devices. Therefore, alternative (binary) serialization formats of the XML data become relevant in order to reduce this overhead. However, using binary-encoded XML should not introduce interoperability issues with existing applications nor add additional complexity to new applications. On top of that, it should have a clear cost reduction over the current plain-text serialization format. A first technology is developed within the ISO/IEC Moving Picture Experts Group, namely the Binary MPEG Format for XML. It provides good compression efficiency, ability to (partially) update existingXMLtrees, and facilitates random access into, and manipulation of, the binary-encoded bit stream. Another technique is based on the Abstract Syntax Notation One specification with the Packed Encoding Rules created by the ITU-T. This paper evaluates both techniques as alternative XML serialization formats and introduces a solution for the interoperability concerns. This solution and the alternative serialization formats are validated against two real-life use cases in terms of processing speed and cost reduction. The efficiency of the alternative serialization formats are compared to a classic plain text compression technique, in particular ZIP compression.}, address = {London}, language = {EN}, publisher = {Springer} } @InProceedings{Timmerer2005e, author = {Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proc. of the First International Conference on Automated Production of Cross Media Content for Multi-channel Distribution (AXMEDIS 2005)}, title = {MPEG Standards enabling Universal Multimedia Access}, year = {2005}, address = {Florence, Italy}, editor = {Nesi, Paolo and Kia, Ng and Delgado, Jamie}, month = dec, pages = {187-196}, publisher = {Firenze University Press}, abstract = {Over the last decade, a wide spectrum of (multi­media) content has become available to an increasing number of users who desire to access it through various devices and over heterogeneous networks. Interoperability is the key for enabling transparent and augmented use of (multimedia) content across a wide range of networks and devices. Standardization efforts within the Moving Picture Experts Group (MPEG), in particular MPEG-7 and MPEG-21, aim to provide appropriate tools for achieving this goal of Universal Multimedia Access (UMA). This tutorial provides, in the first place, the concepts of UMA and corresponding MPEG-7 metadata tools built to support these concepts. Subsequently, the vision, an overview, and the state of the art of the emerging MPEG-21 Multimedia Framework are given. Finally, MPEG-21 Digital Item Adaptation (DIA) tools which implement the “Terminal and Networks Characteristics” key element within the whole framework are illustrated in detail. The goal of MPEG-21 DIA is to achieve interoperable transparent access to (distributed) advanced multimedia content by shielding users from network and terminal installation, configuration, management and implementation issues.}, issn = {88-8453-355-4}, language = {EN}, talktype = {none} } @InProceedings{Timmerer2005d, author = {Timmerer, Christian and Frank, Thomas and Hellwagner, Hermann and Heuer, Jörg and Hutter, Andreas}, booktitle = {Proc. SPIE}, title = {Efficient Processing of MPEG-21 Metadata in the Binary Domain}, year = {2005}, address = {Boston}, editor = {Vetro, Anthony and Wen Chen, Chang and Kuo, C-C Jay and Zhang, Tong and Tian, Qi and Smith, John R}, month = oct, pages = {32-43}, publisher = {Spie}, series = {Multimedia Systems and Applications VIII}, abstract = {XML-based metadata is widely adopted across the different communities and plenty of commercial and open source tools for processing and transforming are available on the market. However, all of these tools have one thing in common: they operate on plain text encoded metadata which may become a burden in constrained and streaming environments, i.e., when metadata needs to be processed together with multimedia content on the fly. In this paper we present an efficient approach for transforming such kind of metadata which are encoded using MPEG's Binary Format for Metadata (BiM) without additional en-/decoding overheads, i.e., within the binary domain. Therefore, we have developed an event-based push parser for BiM encoded metadata which transforms the metadata by a limited set of processing instructions – based on traditional XML transformation techniques - operating on bit patterns instead of cost-intensive string comparisons.}, keywords = {universal multimedia access, multimedia adaptation, compressed-domain metadata processing, bitstream adaptation in constrained and streaming environments, MPEG-21, Digital Item Adaptation, generic Bitstream Syntax Description}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Efficient Processing of MPEG-21 Metadata in the Binary Domain.pdf}, talktype = {none} } @Article{Timmerer2005b, author = {Timmerer, Christian and Hellwagner, Hermann}, journal = {IEEE Multimedia Magazine}, title = {Interoperable Adaptive Multimedia Communication}, year = {2005}, month = jan, number = {1}, pages = {74-79}, volume = {12}, abstract = {Digital Item Adaptation (DIA) has been recently standardized as Part 7 of the MPEG-21 Multimedia Framework. This standard specifies tools enabling interoperable communication and adaptation of so-called Digital Items. The adaptation process becomes ever more difficult due to the heterogeneity of terminals and networks utilizing different types of multimedia contents encoded in various coding formats. Other aspects are the users� preferences and accessibility characteristics as well as the natural environment in which the content is consumed. This article describes how to use the tools within DIA in order to build a device and coding format independent adaptation module enabling interoperable multimedia communication.}, address = {Los Alamitos, USA}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Interoperable Adaptive Multimedia Communication.pdf}, publisher = {IEEE Computer Society} } @InProceedings{Timmerer2005a, author = {Timmerer, Christian and Kofler, Ingo and Liegl, Johannes and Hellwagner, Hermann}, booktitle = {Proceedings of the Seventh IEEE International Symposium on Multimedia (ISM)}, title = {An Evaluation of Existing Metadata Compression and Encoding Technologies for MPEG-21 Applications}, year = {2005}, address = {Washington, DC, USA}, editor = {Tsai, Jeffrey and Mühlhäuser, Max and Takizawa, Makoto}, month = dec, pages = {534-539}, publisher = {IEEE}, series = {ISM}, abstract = {XML-based metadata for digital media is becoming increasingly important, as a consequence also calling for efficient encoding and compression schemes for the storage and transport of this metadata. Moreover, support for streaming the XML metadata in conjunction with the media data is highly desirable. Such support is provided, for instance, by MPEG's Binary Format for Metadata (BiM) encoding approach, which facilitates fragmenting, delivering, and accessing the metadata in so- called Access Units (AUs). In this paper, we present a quantitative evaluation of existing XML metadata compression and encoding techniques, reaching from widely used state-of-the-art data compression algorithms to sophisticated XML-aware encoding schemes. The comparison is based on compressing MPEG-21 generic Bitstream Syntax Descriptions (gBSDs) which can grow to non-negligible sizes. The main conclusion from this investigation is that in terms of pure compression efficiency on XML files, the BiM approach (exemplified by the MPEG reference software as well as a commercial version thereof) is comparable – in terms of performance – with traditional data or specific XML compression tools. However, when XML metadata have to be fragmented, compressed, and streamed in such fragments, the results indicate that the BiM approach is superior to the other schemes.}, doi = {10.1109/ISM.2005.31}, language = {EN}, location = {Irvine, CA, USA}, pdf = {https://www.itec.aau.at/bib/files/An Evaluation of Existing Metadata Compression and Encoding Technologies for MPEG-21 Applications.pdf}, talkdate = {2005.12.12}, talktype = {registered} } @Article{Schojer2005, author = {Schojer, Peter and Böszörmenyi, Laszlo and Hellwagner, Hermann}, journal = {Scalable Computing: Practice and Experience}, title = {An Adaptive Standard Meta-data Aware Proxy Cache}, year = {2005}, month = jul, number = {No 2}, pages = {93-104}, volume = {Vol 6}, abstract = {Multimedia is gaining ever more importance on the Internet. This increases the need for intelligent and efficient video caches. A promising approach to improve caching efficiency is to adapt videos. With the availability of MPEG-4 it is possible to develop a standard compliant proxy cache that allows fast and efficient adaptation. We propose a modular design for an adaptive MPEG-4 video proxy that supports efficient full and partial video caching in combination with filtering options that are driven by the terminal capabilities of the client. We use the native scalability operations provided by MPEG-4, the MPEG-7 standard to describe the scalability options for a video and the emerging MPEG-21 standard to describe the terminal capabilities. We restrict ourselves to full video caching. The combination of adaptation with MPEG-4, MPEG-7 and client terminal capabilities is to the best of our knowledge unique and will increase the quality of service for end users. Key words: Adaptation, MPEG-4, MPEG-7, MPEG-21, adaptive proxy, caching.}, address = {Timisoara, Romania}, language = {EN}, publisher = {SCPE} } @InProceedings{Ransburg2005a, author = {Ransburg, Michael and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Proceedings of the First International Conference on Multimedia Services Access Networks (MSAN 2005)}, title = {Transport mechanisms for metadata-driven distributed multimedia adaptation}, year = {2005}, address = {Orlando, USA}, editor = {N,A}, month = jun, pages = {25-29}, publisher = {IEEE CS Press}, abstract = {The information revolution of the last decade has resulted in a phenomenal increase in the quantity of multimedia content available to an increasing number of different users with different preferences who access it through a plethora of devices and over heterogeneous networks. In order to address the amount of different content types, MPEG-21 Digital Item Adaptation (DIA) introduces interoperable description tools which enable coding format independent adaptation. Bandwidthefficient transport of the content to terminals with different capabilities and through a variety of access networks with various characteristics requires adaptation facilities not only on the server but also within the network. In this paper we present transport mechanisms for MPEG-21-based metadata enabling generic adaptation within the network. Three different transport mechanisms for delivering this metadata in conjunction with the corresponding multimedia content are evaluated and a payload format for the transport of this metadata is presented. Furthermore, we performed measurements which demonstrate the bandwidth benefits of our distributed adaptation approach compared to server-centric adaptation in a multicast scenario. Finally, we applied various encoding formats for the metadata which further reduces the metadata overhead.}, doi = {10.1109/MSAN.2005.1489936}, isbn10 = {0-7803-9319-8}, keywords = {MPEG-21 Digital Item Adaptation; distributed multimedia adaptation; metadata transport}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Transport Mechanisms for Metadata-driven Distributed Multimedia Adaptation.pdf}, talktype = {none} } @InProceedings{Ransburg2005, author = {Ransburg, Michael and Hellwagner, Hermann}, booktitle = {Proceedings of IASTED International Conference on Internet and Multimedia Systems and Applications (EuroIMSA 2005)}, title = {Generic Streaming of Multimedia Content}, year = {2005}, address = {Grindelwald}, editor = {Hamza, Mohamed H}, month = feb, pages = {324-330}, publisher = {ACTA Press}, abstract = {The growing demand for multimedia information by different types of users equipped with a large variety of devices and connecting through different kinds of networks results in an increasing amount of different multimedia formats. Research is currently concentrating on the adaptation of the contents in order to provide Universal Multimedia Access (UMA) for the content consumer. But this does not solve the problem of the content provider, who still has to signal this variety of different multimedia formats to the consumer. In this contribution, we show a way to stream any type of multimedia format based on generic hint information. This hint information is based on a generic bit stream syntax description (gBSD) which is used for format-independent content adaptation within the MPEG-21 Multimedia Framework. Ultimately, this can lead to a frame-work which allows generic streaming and generic adaptation anywhere in the network.}, keywords = {Streaming, Metadata, Multimedia, MPEG-21, XML andDigital Item Adaptation.}, language = {EN}, talktype = {none} } @InProceedings{Prangl2005, author = {Prangl, Martin and Timmerer, Christian and Leopold, Klaus and Hellwagner, Hermann}, booktitle = {ELMAR, 2005. 47th International Symposium}, title = {DVB-based MPEG-21 digital items for adaptive multimedia streaming}, year = {2005}, address = {Zadar}, editor = {Grgic, M and Grgic, S and Kos, T}, month = jun, pages = {135-138}, publisher = {IEEE Xplore}, abstract = {In this paper, we present a prototype application that receives Digital Video Broadcast (DVB) TV streams on a PC, extracts semantic and syntactic metadata from the MPEG-2 Transport Stream (TS), maps them to MPEG-7 compliant descriptors, and packs these metadata and the associated multimedia content into standard compliant MPEG-21 Digital Items (DIs). In this form, i.e., as DIs, the DVB content can be searched and accessed by clients such as PCs and PDAs, and can be transported over IP networks. The DVB server can be used as a live source of multimedia content to demonstrate multimedia streaming (e.g., via RTP) and adaptation to diverse devices.}, keywords = {DVB, metadata, MPEG-7, MPEG-21, Digital Items}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/DVB-based MPEG-21 Digital Items for Adaptive Multimedia Streaming.pdf}, talktype = {none} } @InProceedings{Kropfberger2005, author = {Kropfberger, Michael and Hellwagner, Hermann}, booktitle = {Proc. of the IEEE International Workshop on Multimedia Signal Processing}, title = {Combining Stream Switching with Fine-grained Intra-stream Adaptation for Adaptive Video Streaming}, year = {2005}, address = {Shanghai}, editor = {Zhuang, Xinhua and Sorensen, J and Wu, Qiang and Qing, Shi Y and Ostermann, J and Man, H and Goldgof, D}, month = nov, pages = {373-376}, publisher = {IEEE Computer Society}, abstract = {Video streaming systems in best effort networks have to somehow cope with dynamically changing bandwidth. Various scalable video codecs allow intra-stream adaptation by use of temporal, spatial, or quality (SNR) scalability; optimizations for finer grained scalability are available as layered coding and FGS techniques. However, if there is no scalable video stream at hand, stream switching among pre-encoded stream versions of different bitrates and qualities allows at least coarse-grained adaptation. Those different approaches compete to be the most efficient solution for adaptive video streaming. However, this paper will show that the efficacy is significantly increased by combining those approaches. As will be discussed, the combination of coarse-grained stream switching and temporal intra-stream adaptation offers better visual results and more stable client buffer behavior than the denoted approaches used separately.}, doi = {10.1109/MMSP.2005.248654}, isbn10 = {0-7803-9288-4}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Combining stream switching with fine-grained intra-stream adaptation for adaptive video streaming.pdf}, talkdate = {IEE}, talktype = {none} } @InProceedings{Hutter2005, author = {Hutter, Andreas and Amon, Peter and Panis, Gabriel and Delfosse, Eric and Ransburg, Michael and Hellwagner, Hermann}, booktitle = {Image Processing, 2005. ICIP 2005. IEEE International Conference on}, title = {Automatic Adaptation of Streaming Multimedia Content in a Dynamic and Distributed Environment}, year = {2005}, address = {Genova, Italy}, editor = {IEEE,}, month = sep, pages = {716-719}, publisher = {IEEE Computer Society}, abstract = {The diversity of end-terminal and access network capabilities as well as the dynamic nature of wireless connections pose significant challenges to providers of multimedia streaming services. In this paper, we present a system based on MPEG-21 Digital Item Adaptation (DIA) technologies that automatically adapts scalable multimedia resources, like upcoming MPEG-21 Scalable Video Coding (SVC) streams, in a generic and transparent way to the user and session context. This context includes terminal and network capabilities as well as user characteristics. A server side adaptation engine reacts to context changes by dynamic decision taking and accordingly modified bitstream adaptation. Furthermore, novel concepts are presented that facilitate multimedia adaptation in a distributed fashion along the delivery path.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Automatic Adaptation of streaming multimedia content in a dynamic and distributed environment.pdf}, talktype = {none} } @Article{Devillers2005, author = {Devillers, Sylvain and Timmerer, Christian and Heuer, Jörg and Hellwagner, Hermann}, journal = {IEEE Transactions on Multimedia}, title = {Bitstream Syntax Description-Based Adaptation in Streaming and Constrained Environments}, year = {2005}, month = jun, number = {No. 3}, pages = {463-470}, volume = {Special Issue on MPEG-21, Vol. 7}, abstract = {The seamless access to rich multimedia content on any device and over an network, usually known as Universal Multimedia Access, requires interoperable description tools and adaptation techniques to be developed. To address the latter issue, MPEG-21 Digital Item Adaptation (DIA) introduces the Bitstream Syntax Description (BSD) framework, which provides tools for adapting multimedia content in a generic (i.e., coding format independent) way. The basic idea is to use the eXtensible Markup Language (XML) to describe the high-level structure of a binary media bitstream, to transform its description (e.g., by means of eXtensible Stylesheet Language Transformations, XSLT), and to construct the adapted media bitstream from the transformed description. This paper presents how this basic BSD framework, initially developed for non-streamed content and suffering from inherent limitations and high memory consumption of XML-related technologies such as XSLT, can be advanced and efficiently implemented in a streaming environment and on resource-constrained devices. Two different attempts to solve the inherent problems are described. The first approach proposes an architecture based on the streamed processing of SAX (Simple Application Programming Interface for XML) events and adopts STX (Streaming Transformations for XML) as an alternative to XSLT, whereas the second approach breaks a BSD up into well-formed fragments called Process Units (PUs) that can be processed individually by a standard XSLT processor. The current status of our work as well as directions for future research are given.}, address = {Piscataway, USA}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Bitstream Syntax Description-based Adaptation in Streaming and Constrained Environments.pdf}, publisher = {IEEE} } @InProceedings{DeSutter2005, author = {De Sutter, Robbie and Timmerer, Christian and Hellwagner, Hermann and Van de Walle, Rik}, booktitle = {Proceedings of IASTED International Conference on Internet and Multimedia Systems and Applications (EuroIMSA 2005)}, title = {Multimedia Metadata Processing: A Format Independent Approach}, year = {2005}, address = {Zürich, Schweiz}, editor = {Hamza, M H}, month = {jan}, pages = {343-348}, publisher = {ACTA Press}, abstract = {In multimedia applications, XML is being increasingly used to represent metadata; examples are MPEG-7 multimedia description schemes and MPEG-21 usage environment descriptions. As with the media data, the size of, or the overhead induced by, the XML metadata is important, particularly when used on constrained mobile devices. Therefore, compression (binary encoding) of the XML data becomes relevant to reduce this overhead. Within the MPEG-7 standardization effort, a Binary Format for Metadata (BiM) was developed, ´providing good compression efficiency and facilitating random access into, and manipulation of, the binary encoded bit stream. However, using binary encoded XML should not introduce interoperability issues with existing applications, nor add additional complexity to new applications. In this paper we investigate a solution for this issue by handling the binary encoded XML data by the XML parser. As such, applications do not need to be aware of the type of encoding of the XML data. In this paper, we introduce such an XML parser and evaluate its usability in different scenarios. We measure the memory requirements and compare the processing speed of parsing binary encoded XML to plain text XML.}, issn = {14827905}, keywords = {Multimedia Information Systems, Multimedia Communication Systems, Multimedia Metadata, Binary Encoded XML, MPEG-7 BiM}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Multimedia Metadata Processing.pdf}, talktype = {none} } @Article{Tusch2004, author = {Tusch, Roland and Böszörmenyi, Laszlo and Goldschmidt, Balázs and Hellwagner, Hermann and Schojer, Peter}, journal = {Computer Science and Information Systems}, title = {Offensive and Defensive Adaptation in Distributed Multimedia Systems}, year = {2004}, month = {jan}, number = {No 1}, pages = {49-77}, volume = {Vol. 1}, abstract = {Adaptation in multimedia systems is usually restricted to defensive, reactive media adaptation (often called stream-level adaptation). We argue that offensive, proactive, system-level adaptation deserves not less attention. If a distributed multimedia system cares for overall, end-to-end quality of service then it should provide a meaningful combination of both. We introduce an adaptive multimedia server (ADMS) and a supporting middleware which implement offensive adaptation based on a lean, flexible architecture. The measured costs and benefits of the offensive adaptation process are presented. We introduce an intelligent video proxy (QBIX), which implements defensive adaptation. The cost/benefit measurements of QBIX are presented elsewhere. We show the benefits of the integration of QBIX in ADMS. Offensive adaptation is used to find an optimal, user-friendly configuration dynamically for ADMS, and defensive adaptation is added to take usage environment (network and terminal) constraints into account.}, address = {Novi Sad}, language = {EN}, publisher = {ComSIS} } @InProceedings{Timmerer2004, author = {Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Informatik 2004 : Informatik verbindet; Band 2, Beiträge der 34. Jahrestagung der Gesellschaft für Informatik e.V. (GI), Ulm, 20.-24. September 2004}, title = {Interoperable multimediale Kommunikation im Internet mittels MPEG-21 Digital Item Adaptation}, year = {2004}, address = {Bonn}, editor = {Dadam, Peter and Reichert, Manfred}, month = {jan}, pages = {301-305}, publisher = {Gesellschaft für Informatik}, series = {Lecture Notes in Informatics, Proceedings}, abstract = {Digital Item Adaptation (DIA) ist der jüngste Standard im Rahmen des ISO/IEC MPEG-21 Multimedia Frameworks. Dieser Standard spezifiziert Deskriptoren und Konzepte (Tools) für die interoperable Kommunikation und ggf. Adaption von komplexen digitalen multimedialen Objekten, sog. Digital Items. Schwierigkeiten der Kommunikation und ggf. die Notwendigkeit der Adaption multimedialer Inhalte entstehen durch die Heterogenität und Beschränkungen der durchlaufenen Netzwerke (z.B. im heutigen Internet) und der benutzten Endgeräte sowie durch unterschiedliche Präferenzen und Profile der Nutzer. Dieser Artikel beschreibt eine endgeräte- und codierformat-unabhängige Komponente zur Adaption von Digital Items an verschiedene mobile Endgeräte und Netzcharakteristika.}, isbn10 = {3885793792}, isbn13 = {978-3885793793}, issn = {3-88579-380-6}, language = {DE}, pdf = {https://www.itec.aau.at/bib/files/Interoperable multimediale Kommunikation im Internet.pdf}, talktype = {none} } @TechReport{Schojer2004, author = {Schojer, Peter and Böszörmenyi, Laszlo and Hellwagner, Hermann}, institution = {Institute of Information Technology ({ITEC}), Klagenfurt University}, title = {QBIX-G: A Quality Based Intelligent proXy Gateway}, year = {2004}, address = {Klagenfurt, Austria}, month = {jan}, abstract = {Due to the increasing availability of audio/visual data on the Internet, proxy caching is gaining on importance as a performance factor. This increase is accompanied by a diversification in the end terminals, which calls for media gateways and filters. An adaptive proxy is presented which performs (1) caching, (2) filtering and (3) media gateway functionality in one. The proxy can perform media adaptation -- using transcoding -- on its own. A cost model is presented which incorporates user requirements, terminal capabilities and video variations in one formula. Based on this model, the proxy acts as a general broker of different user requirements and of different video variations. This is a first step towards "What You Need is What You Get" (WYNIWYG) video services, which deliver videos to users in exactly that quality what they need and what they want to pay for. The MPEG-7 and MPEG-21 standards enables this in an interoperable way. A detailed evaluation based on a series of measurements is provided.}, language = {EN}, pages = {24} } @InProceedings{Leopold2004a, author = {Leopold, Klaus and Jannach, Dietmar and Hellwagner, Hermann}, booktitle = {Multimedia Software Engineering}, title = {A Knowledge and Component Based Multimedia Adaptation Framework}, year = {2004}, address = {Los Alamitos, USA}, editor = {Werner, Bob}, month = dec, pages = {1-8}, publisher = {IEEE Computer Society}, abstract = {The rapid evolution in the hardware sector brought up various (mobile) end user devices like PDAs or cell phones on which online multimedia content can be consumed. Due to different capabilities of these devices as well as individual user preferences, the original multimedia resources have to be adapted in order to fit the specific devices’ constraints and to meet the users’ requirements. Given the high variety of possible adaptation operations both on the format as well as the content level, an intelligent multimedia server must be able to integrate multiple existing and specialized adaptation tools. In this paper, we demonstrate how the usage of modular software components and declarative descriptions of component behavior enables us to develop extensible multimedia adaptation systems. The precise semantics of the utilized functionality description mechanism as well as the defined vocabulary from existing and emerging multimedia standards also allows us to automatically assemble adaptation chains that are executed on a given resource involving multiple, externally provided software components.}, issn = {0-7695-2217-3}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A Knowledge and Component Based Multimedia Adaptation Framework.pdf}, talktype = {none} } @InProceedings{Leopold2004, author = {Leopold, Klaus and Jannach, Dietmar and Hellwagner, Hermann}, booktitle = {Proceedings of SPIE, Internet Multimedia Mangement Systems V}, title = {Knowledge-based media adaptation}, year = {2004}, address = {Bellingham, WA}, editor = {Smith, John R and Zhang, Tong and Panchanathan, Sethuraman}, month = oct, pages = {111-120}, publisher = {SPIE- The International Society for Optical Engineering}, series = {SPIE Proceedings Series}, abstract = {This paper introduces the principal approach and describes the basic architecture and current implementation of the knowledge-based multimedia adaptation framework we are currently developing. The framework can be used in Universal Multimedia Access scenarios, where multimedia content has to be adapted to specific usage environment parameters (network and client device capabilities, user preferences). Using knowledge-based techniques (state-space planning), the framework automatically computes an adaptation plan, i.e., a sequence of media conversion operations, to transform the multimedia resources to meet the client's requirements or constraints. The system takes as input standards-compliant descriptions of the content (using MPEG-7 metadata) and of the target usage environment (using MPEG-21 Digital Item Adaptation metadata) to derive start and goal states for the planning process, respectively. Furthermore, declarative descriptions of the conversion operations (such as available via software library functions) enable existing adaptation algorithms to be invoked without requiring programming effort. A running example in the paper illustrates the descriptors and techniques employed by the knowledge-based media adaptation system.}, doi = {10.1117/12.577420}, edition = {Volume 5601}, isbn13 = {9780819455543}, issn = {0277-786X}, language = {EN}, talktype = {none} } @InProceedings{Kropfberger2004a, author = {Kropfberger, Michael and Hellwagner, Hermann}, booktitle = {Multimedia and Expo, 2004. ICME '04. 2004 IEEE International Conference on}, title = {Evaluation of RTP immediate feedback and retransmission extensions}, year = {2004}, address = {kA}, editor = {IEEE,}, month = jun, pages = {1751-1754}, publisher = {IEEE Xplore}, abstract = {Modern video streaming servers should adapt, and switch quality levels of, the streamed data according to precise and timely feedback about the network conditions, and should also incorporate selective retransmissions of important reference frames (I- and P-VOPs). This paper evaluates two recent IETF Internet Drafts on RTP extensions for immediate feedback and retransmission and shows, in conjunction with temporal video adaptation, how a substantial visual quality gain can be achieved by using those extensions (up to 4.4 dB PSNR under lossy conditions).}, doi = {10.1109/ICME.2004.1394593}, edition = {Vol. 3}, isbn10 = {0-7803-8603-5}, issn = {0-7803-8604-3}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Evaluation of RTP immediate feedback and retransmission extensions.pdf}, talktype = {none}, url = {http://www.icme2004.org} } @InProceedings{Kropfberger2004, author = {Kropfberger, Michael and Leopold, Klaus and Hellwagner, Hermann}, booktitle = {Multimedia Signal Processing, 2004 IEEE 6th Workshop on}, title = {Quality variations of different priority-based temporal video adaptation algorithms}, year = {2004}, address = {kA}, editor = {IEEE,}, month = {jan}, pages = {183-186}, publisher = {IEEE Xplore}, abstract = {If videos are streamed over heterogeneous networks like the Internet, severe bandwidth fluctuations can emerge which hamper seamless transmission to the end user. To overcome this issue, a video's quality and, as a consequence, its bandwidth requirements can be reduced. Quality reduction in the temporal domain (i.e., frame dropping) turned out to be a promising approach because it is fast and easy to perform. In this paper, we present different approaches for temporal video adaptation and we investigate their performance in terms of the achieved visual quality when applied on several videos. The results show that our QCTVA approach (quality controlled temporal video adaptation), based on PSNR evaluation of frames, yields superior quality.}, doi = {10.1109/MMSP.2004.1436384}, isbn10 = {0-7803-8578-0}, issn = {0-7803-8578-0}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Quality Variations of Different Priority-based Temporal Video Adaptation Algorithms.pdf}, talktype = {none} } @InProceedings{Jannach2004b, author = {Jannach, Dietmar and Leopold, Klaus and Timmerer, Christian and Hellwagner, Hermann}, booktitle = {Web Information Systems - WISE 2004}, title = {Toward Semantic Web Services for Multimedia Adaptation}, year = {2004}, address = {Berlin, Heidelberg, New York}, editor = {Zhou, Xiaofang and Su, Stanley and Papazoglou, Mike and Orlowska, Maria and Jeffery, Keith}, month = nov, pages = {641-652}, publisher = {Springer}, series = {LNCS}, abstract = {Abstract. Universal Multimedia Access (UMA), where users can consume any multimedia resource anywhere at any time, is the driving vision of ongoing ISO/IEC Moving Picture Experts Group (MPEG) standardization efforts. In that context, intelligent adaptation means that before resources are sent over the network, they are prepared according to the client’s device capabilities, the network conditions, or even the user’s content preferences. In this paper, we argue that Semantic Web Services can serve as a key enabling technology to achieve the goals of UMA. As the standards evolve, more and more specialized software tools will be available that provide specific functionalities for adapting the media in different dimensions. When the functionality of such tools is described declaratively with the means of Semantic Web Services technology, intelligent adaptation network nodes can be developed, capable of automatically composing multi-step adaptation sequences and dynamically integrating such services available on the Web. This paper describes the architecture and a prototypical implementation of an intelligent adaptation node that supports automatic, knowledge-based service composition which is made possible by the shared domain ontology defined in MPEG metadata standards.}, doi = {10.1007/978-3-540-30480-7_66}, issn = {0302-9743}, language = {EN}, talktype = {none} } @InProceedings{Jannach2004a, author = {Jannach, Dietmar and Leopold, Klaus and Hellwagner, Hermann}, booktitle = {Proceedings of the 17th International Conference on Industrial \& Engineering Applications of Artificial Intelligence \& Expert Systems}, title = {An extensible framework for knowledge-based multimedia adaptation}, year = {2004}, address = {Berlin [u. a.]}, editor = {Orchard, Robert and Yang, Chunsheng and Moonis, Ali}, month = may, pages = {144-153}, publisher = {Springer Verlag}, series = {LNCS}, abstract = {Multimedia content is becoming increasingly important in many areas not only for pure entertainment but also for commercial or educational purposes like, e.g., distance learning or online training. In parallel, the rapid evolution in the hardware sector brought up various new (mobile) end user devices like pocket PCs or mobile phones that are capable of displaying such content. Due to the different capabilities and usage environments of these devices, the basic multimedia content has to be adapted in order to fit the specific devices' capabilities and requirements, whereby such transformations typically include changes in the display size or quality adaptation. Based on the capabilities of the target device that can be expressed using recent multimedia standards like MPEG-21, these adaptation steps are typically carried out by the video server or a proxy node before the data is transferred to the client. In this paper, we present a software framework and implementation of such a multimedia server add-on that advances state-of-the-art technology in two ways. First, the framework supports the integration of various (already existing) multimedia transformation tools based on declarative interface and semantic capability descriptions in a way comparable to Semantic Web Services approaches. Second, by using the components' capability descriptions and the usage environment of the end user device, we employ a knowledge-based planning approach for dynamically constructing and executing the needed transformation program for a specific multi-media content request.}, issn = {3-5402-2007-0}, language = {EN}, talktype = {none} } @InProceedings{Jannach2004, author = {Jannach, Dietmar and Leopold, Klaus and Hellwagner, Hermann and Timmerer, Christian}, booktitle = {Proceedings of the 5th International Workshop on Image Analysis for Multimedia Interactive Services}, title = {A Knowledge Based Approach for Multi-step Media Adaptation}, year = {2004}, address = {Lisboa, Portugal}, editor = {Pereira, Fernando and Correia, Paulo Lobato}, month = apr, pages = {1-4}, publisher = {Instituto Superior Téchnico}, abstract = {In order to enable transparent and augmented use of multimedia resources across a wide range of networks and devices, the forthcoming MPEG-21 standard aims at integrating the various existing technologies for delivery and consumption of digital content in a common multimedia framework. Digital Item Adaptation is one of the core concepts of the framework that will support the adaptation of multimedia resources to device capabilities, underlying network characteristics, or the user’s preferences. The scope of the standardization, however, is limited to the definition of description tools and does not deal with the internals of the adaptation process itself. In this paper, we first discuss the requirements of the resource adaptation component of an adaptation engine. These requirements include, for instance, openness for the integration of external multimedia transforming tools as well as intelligent decision taking when determining the set of required adaptation steps. We also present a prototype of a simple video resource adaptation engine that completely relies on descriptions of the resource itself (MPEG-7), the usage environment of the resource (MPEG-21), as well as declarative descriptions of the transformation tools. The prototype employs a knowledge-based engine for finding and executing the needed adaptation sequences.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A knowledge supported approach for multi-step media adaptation.pdf}, talktype = {none} } @InProceedings{DeSutter2004, author = {De Sutter, Robbie and Timmerer, Christian and Hellwagner, Hermann and Van de Walle, Rik}, booktitle = {Proceedings of the International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS2004)}, title = {Evaluation of Models for Parsing Binary Encoded XML-based Metadata}, year = {2004}, address = {Piscataway, USA}, editor = {Ko, Sung Jea}, month = nov, pages = {1-6}, publisher = {IEEE}, abstract = {In multimedia applications, XML is being increasingly used to represent metadata; examples are MPEG-7 multimedia description schemes and MPEG-21 usage environment descriptions. As with the media data, the size of, or the overhead induced by, the XML metadata is important, particularly when used on constrained mobile devices. Therefore, compression (binary encoding) of the XML data becomes relevant to reduce this overhead. Within the MPEG-7 standardization effort, a Binary Format for Metadata (BiM) was developed, providing good compression efficiency and facilitating random access into, and manipulation of, the binary encoded bit stream. In order to support processing of metadata streams in the binary domain and making this task for client applications as simple as possible, we are developing a universal parser for handling both plain text and binary encoded XML-based metadata. The parser exposes a single interface making it transparent for the application whether a plain text or a binary XML document is being processed. As part of this effort, this paper provides a detailed study of five existing XML parser models and evaluates their applicability to serve as a model for parsing binary XML data, encoded using the BiM codec. Additionally, the parser models are investigated against important usage scenarios enabled by BiM, such as dynamic updates of XML data. From the five models, two are rejected and one is only applicable for domain specific applications. Of the remaining two, one model is proposed as preferred model because of different advantages over the other model.}, isbn10 = {0780386396}, isbn13 = {978-0780386396}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Evaluation of Models for Parsing Binary Encoded XML-based Metadata.pdf}, talktype = {none} } @InProceedings{Tusch2003b, author = {Tusch, Roland and Böszörmenyi, Laszlo and Goldschmidt, Balázs and Hellwagner, Hermann and Schojer, Peter}, booktitle = {Proceedings of ICETA 2003, 2nd International Conference on Emerging Telecommunications Technologies and Applications}, title = {Offensive and Defensive Adaptation in Distributed Multimedia Systems}, year = {2003}, address = {Košice, Slovak Republic}, editor = {Jakab, F and Cizmar, A}, month = sep, pages = {17-19}, publisher = {Elfa}, abstract = {Adaptation is usually restricted to defensive, reactive media adaptation (often called stream-level adaptation). We argue that offensive, proactive, system-level adaptation deserves not less attention. If a distributed multimedia system cares for overall, end-to-end quality of service then it should provide a meaningful combination of both. We introduce an adaptive multimedia server (ADMS) and a supporting middleware which implement offensive adaptation based on a lean, flexible architecture. The measured costs and benefits of the offensive adaptation process are presented. We introduce an intelligent video proxy (QBIX), which implements defensive adaptation. The cost/benefit measurements of QBIX are presented elsewhere~\citeSchojer03. We show the benefits of the integration of QBIX in ADMS. Offensive adaptation is used to find an optimal, user-friendly configuration dynamically for ADMS, and defensive adaptation is added to take usage environment (network and terminal) constraints into account.}, isbn10 = {8089066674}, issn = {80-89066-06-2}, language = {EN}, talktype = {none} } @InProceedings{Timmerer2003, author = {Timmerer, Christian and Panis, Gabriel and Kosch, Harald and Heuer, Jörg and Hellwagner, Hermann and Hutter, Andreas}, booktitle = {Proceedings of SPIE International Symposium ITCom 2003 on Internet Multimedia Managment Systems IV, Vol. 5242}, title = {Coding format independent multimedia content adaptation using XML}, year = {2003}, address = {Orlando}, editor = {N,A}, month = {jan}, pages = {92-103}, publisher = {SPIE Press}, abstract = {Due to the heterogeneity of the current terminal and network infrastructures, multimedia content needs to be adapted to specific capabilities of these terminals and network devices. Furthermore, user preferences and user environment characteristics must also be taken into consideration. The problem becomes even more complex by the diversity of multimedia content types and encoding formats. In order to meet this heterogeneity and to be applicable to different coding formats, the adaptation must be performed in a generic and interoperable way. As a response to this problem and in the context of MPEG-21, we present an approach which uses XML to describe the high-level structure of a multimedia resource in a generic way, i.e., how the multimedia content is organized, for instance in layers, frames, or scenes. For this purpose, a schema for XML-based bitstream syntax descriptions (generic Bitstream Syntax Descriptions or gBSDs) has been developed. A gBSD can describe the high-level structure of a multimedia resource in a coding format independent way. Adaptation of the resource is based on elementary transformation instructions formulated with respect to the gBSDs. These instructions have been separated from the gBSDs in order to use the same descriptions for different adaptations, e.g., temporal scaling, SNR scaling, or semantic adaptations. In the MPEG-21 framework, those adaptations can be steered for instance by the network characteristics and the user preferences. As a result, it becomes possible for coding format agnostic adaptation engines to transform media bitstreams and associated descriptions to meet the requirements imposed by the network conditions, device capabilities, and user preferences.}, isbn10 = {0819451401}, isbn13 = {978-0819451408}, keywords = {Multimedia, Adaptation, Interoperability, XML, MPEG-21, Digital Item Adaptation}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Coding format independent multimedia content adaptation.pdf}, talktype = {none} } @InProceedings{Schojer2003, author = {Schojer, Peter and Böszörmenyi, Laszlo and Hellwagner, Hermann and Penz, Bernhard and Podlipnig, Stefan}, booktitle = {The Twelfth International World Wide Web Conference}, title = {Architecture of a Quality Based Intelligent Proxy (QBIX) for MPEG-4 Videos}, year = {2003}, address = {New York, USA}, editor = {Hencsey, Gusztáv and White, Bebo}, month = {jan}, pages = {394-402}, publisher = {ACM}, abstract = {Due to the increasing availability and use of digital video data on the Web, video caching will be an important performance factor in the future WWW. We propose an architecture of a video proxy cache that integrates modern multimedia and communication standards. Especially we describe features of the MPEG-4 and MPEG-7 multimedia standards that can be helpful for a video proxy cache. QBIX supports real-time adaptation in the compressed and in the decompressed domain. It uses adaptation to improve the cache replacement strategies in the proxy, but also to realize media gateway functionality driven by the clients' terminal capabilities.}, issn = {1-58113-680-3}, language = {EN}, talktype = {none}, url = {http://www.2003.org} } @Article{Panis2003, author = {Panis, Gabriel and Hutter, Andreas and Heuer, Jörg and Hellwagner, Hermann and Kosch, Harald and Timmerer, Christian and Devillers, Sylvain and Amielh, Myriam}, journal = {Signal Processing: Image Communication}, title = {Bitstream Syntax Description: A Tool for Multimedia Resource Adaptation within MPEG-21}, year = {2003}, month = {jan}, number = {8}, pages = {721-747}, volume = {Vol. 18, Special Issue on Multimedia Adaptation}, abstract = {In this paper, a generic method is described to allow the adaptation of different multimedia resources by a single, media resource-agnostic processor. This method is based on an XML description of the media resource’s bitstream syntax, which can be transformed to reflect the desired adaptation and then be used to generate an adapted version of the bitstream. Based on this concept, two complementary technologies, BSDL and gBS Schema, are presented. The two technologies provide solutions for parsing a bitstream to generate its XML description, for the generic structuring of this description, and the generation of an adapted bitstream using its transformed description. The two technologies can be used as stand-alone tools; however, a joint approach has been developed in order to harmonise the two solutions and exploit their strengths. Since BSDL has been presented in previous publications, this paper is focusing more on the gBS Schema and the joint BSDL/gBS Schema approach.}, address = {Amsterdam, Netherlands}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/Bitstream syntax description.pdf}, publisher = {Elsevier B.V.} } @InProceedings{Ohlenroth2003, author = {Ohlenroth, Mathias and Hellwagner, Hermann}, booktitle = {ICME 2003 Proceedings CD-Rom}, title = {A Protocol for Adaptation-aware Multimedia Streaming}, year = {2003}, address = {NA}, editor = {Mercer, Billene and Cantu, St and Garza, Ch and Stewart, B}, month = jul, pages = {1-4}, publisher = {NA}, abstract = {Multimedia streaming is becoming ever more popular. However, the Internet does not support streaming with its high bandwidth and low latency requirements very well. The problem is that QoS guarantees cannot be given. Hence, communication partners have to deal with rapidly changing connection parameters. This requires sophisticated streaming concepts that can handle these varying conditions using adaptation techniques. Adaptation methods can be dropping layers, dropping access units or transcoding the contents. But this places specific requirements on the underlying protocol. This paper identifies and discusses these requirements and analyzes how existing protocols can meet them. Unfortunately, none of the known protocols can meet all requirements. Hence, we propose a new adaptation-aware multimedia streaming protocol that can operate as required in the given Internet environment. Furthermore, we show how this protocol can be used to carry MPEG-4 audio-visual contents.}, issn = {0-7803-7966-7}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A protocol for adaptation-aware multimedia streaming.pdf}, talktype = {none} } @InProceedings{Leopold2003, author = {Leopold, Klaus and Hellwagner, Hermann and Kropfberger, Michael}, booktitle = {Proc. of SPIE}, title = {QCTVA - Quality Controlled Temporal Video Adaptation}, year = {2003}, address = {NA}, editor = {N,A}, month = sep, pages = {163-174}, publisher = {NA}, abstract = {Multimedia streaming is becoming more and more popular. Seamless video streaming in heterogeneous networks like the Internet turns out as almost impossible due to varying network conditions - streams must be adapted to the current network QoS. Temporal scalability is one of the most reasonable adaptation techniques because it is fast and easy to perform. Today's approaches simply drop frames out of a video without spending much effort on finding an intelligent dropping behavior. This usually leads to good adaptation results in terms of bandwidth consumption but also to suboptimal video quality within the given bounds. Our approach offers analysis of video streams to achieve the qualitatively best temporal scalability. For this reason, we introduce a data structure called modification lattice which represents all frame dropping combinations within a sequence of frames. On the basis of the modification lattice, qualityestimations on frame sequences can be performed. Moreover, a heuristic for fast and efficient quality computation in a modification lattice is presented. Experimental results illustrate that temporal video adaptation based on QCTVA information leads to a better video quality compared to "usual" frame dropping approaches. Furthermore, QCTVA offers frame priority lists for videos. Based on these priorities, numerous adaptation techniques can increase their overall performance when using QCTVA.}, edition = {Vol. 5242}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/QCTVA.pdf}, talktype = {none} } @Book{Kosch2003a, editor = {Kosch, Harald and Hellwagner, Hermann and Böszörmenyi, Laszlo}, publisher = {Springer Verlag}, title = {Euro-Par 2003, Parallel Processing}, year = {2003}, address = {Heidelberg}, month = {aug}, series = {LNCS 2790}, abstract = {Euro-Par is the annual series of international conferences dedicated to the promotion and advancement of all aspects of parallel and distributed computing. The conference normally attracts more than 300 participants coming from universities, research centres and industry.}, isbn10 = {3-540-40788-X}, issn = {0302-9743}, language = {EN}, pages = {1320}, subtitle = {9th International Euro-Par Conference Klagenfurt, Austria}, url = {http://www.springerlink.com/content/978-3-540-40788-1/} } @Article{Boeszoermenyi2003e, author = {Böszörmenyi, Laszlo and Kosch, Harald and Hellwagner, Hermann}, journal = {Parallel Processing Letters}, title = {Best papers of EuroPar 2003}, year = {2003}, issn = {0129-6264}, month = dec, number = {4}, pages = {509-511}, volume = {13}, address = {Heidelberg, Germany}, language = {EN}, publisher = {Springer} } @Article{Boeszoermenyi2003d, author = {Böszörmenyi, Laszlo and Hellwagner, Hermann and Kosch, Harald and Libsie, Mulugeta and Podlipnig, Stefan}, journal = {Signal Processing - Image Communication - Special Issue on Multimedia Adaptation}, title = {Metadata Driven Adaptation in the ADMITS Project}, year = {2003}, issn = {0923-5965}, month = sep, number = {Issue 8}, pages = {749-766}, volume = {Vol. 18}, abstract = {The ADMITS project (Adaptation in Distributed Multimedia IT Systems) is building an experimental distributed multimedia system for investigations into adaptation, which we consider is an increasingly important tool for multimedia systems. A number of possible adaptation entities (server, proxy, clients, routers) are being explored, different algorithms for media, component and application-level adaptations are being implemented and evaluated, and experimental data are being derived to gain insight into when, where and how to adapt, and how individual, distributed adaptation steps interoperate and interact with each other. In this paper the "adaptation-chain" of (MPEG-conforming) metadata based adaptation is described: from the creation stage at the server side, through its usage in the network (actually in a proxy), up to the consumption at the client. The metadata are used to steer the adaptation processes. MPEG-conformant metadata, the so-called variation descriptions, are introduced; an example of a complete MPEG-7 document describing temporal scaling of an MPEG-4 video is given. The meta-database designed to store the metadata is briefly discussed. We describe how the metadata can be extracted from MPEG-4 visual elementary streams and initial results from the temporal video scaling experiment are given. We further present how the metadata can be utilized by enhanced cache replacement algorithms in a proxy server in order to realize quality-based caching; experimental results using these algorithms are also given. Finally, an adaptive query and presentation interface to the meta-.}, address = {Oxford, United Kingdom}, language = {EN}, publisher = {Elsevier}, url = {http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%232003%23999819991%234} } @InProceedings{Schojer2002, author = {Schojer, Peter and Böszörmenyi, Laszlo and Hellwagner, Hermann}, booktitle = {Distributed and parallel systems: cluster and grid computing. Proceedings of International Conference on Distributed and Parallel Systems (DAPSYS 02), Linz, Austria.}, title = {An Adaptive MPEG-4 Proxy Cache}, year = {2002}, address = {Boston [u. a.]}, editor = {Kascuk, Péter and Kranzlmüller, Dieter and Németh, Zsolt and Volkert, Jens}, month = aug, pages = {149-156}, publisher = {Kluwer Academic Publishers}, series = {The Kluwer international series in engineering and computer science}, abstract = {Multimedia is gaining ever more importance on the Internet. This increases the need for intelligent and efficient video caches. Typical Web proxies were not designed to efficiently support the caching of videos. A promising approach to improve caching efficiency is to adapt videos. With the availability of MPEG-4 it is possible to develop a standard compliant proxy that allows fast and efficient adaptation. We propose a modular design for an adaptive MPEG-4 video proxy that supports efficient full and partial video caching in combination with filtering options that are driven by the terminal capabilities of the client. We use the native scalability operations provided by MPEG-4 and use the emerging MPEG-7 standard to describe the scalability options for a video. The proxy parses the MPEG-7 description and decides, based on this description and the terminal capabilities of the client, which adaptation step to choose. Simple MPEG-4 audio-visual streams are supported by filter operations in the compressed domain that realize several temporal scaling algorithms and color reduction. In this paper, we will restrict ourselves to full video caching. The combination of adaptation with MPEG-4, MPEG-7 and client terminal capabilities is to the best of our knowledge unique and will increase the quality of service for end users.}, issn = {1-4020-7209-0}, keywords = {adaptation, MPEG-4, MPEG-7, adaptive proxy, caching}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/An Adaptive MPEG-4 Proxy Cache.pdf}, talktype = {none} } @InProceedings{Ohlenroth2002, author = {Ohlenroth, Matthias and Hellwagner, Hermann}, booktitle = {ICME Proceedings}, title = {RTP Packetization of MPEG-4 Elementary Streams}, year = {2002}, address = {NA}, editor = {IEEE,}, month = mar, pages = {1-4}, publisher = {IEEE Xplore}, abstract = {Multimedia streaming becomes ever more popular. The multimedia standard MPEG-4 has been designed to support scenes of different levels of complexity and applications with low bandwidth requirements up to very high bandwidth requirements. One protocol suitable to transfer this kind of data over IP networks is the real-time transport protocol (RTP). This report describes standardized and proposed payload formats that support the transport of MPEG-4 elementary streams over RTP connections. These RTP packetization formats are compared w.r.t. their suitability for the adaptation (scaling) of the media data within the network, i.e., by advanced routers or proxy caches. This adaptation process is governed by metadata that need to be transferred and inspected in conjunction with the media streams.}, issn = {0-7803-7305-7}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/RTP Packetization of MPEG-4 Elementary Streams.pdf}, talktype = {none}, url = {http://www.icme2002.org/} } @Article{Hellwagner2002a, author = {Hellwagner, Hermann and Ohlenroth, Matthias}, journal = {Future Generation Computer Systems}, title = {VI Architecture Communication Features and Performance on the Giganet Cluster LAN}, year = {2002}, issn = {0167-739X}, month = jan, number = {Issue 3}, pages = {421-433}, volume = {Vol. 18}, abstract = {The virtual interface (VI) architecture standard was developed to satisfy the need for a high throughput, low latency communication system required for cluster computing. VI architecture aims to close the performance gap between the bandwidths and latencies provided by the communication hardware and visible to the application, respectively, by minimizing the software overhead on the critical path of the communication. This paper presents the results of a performance study of one VI architecture hardware implementation, the Giganet cLAN (cluster LAN). The focus of the study is to assess and compare the performance of different VI architecture data transfer modes and specific features that are available to higher-level communication software like MPI in order to aid the implementor to decide which VI architecture options to employ for various communication scenarios. Examples of such options include the use of send/receive vs. RDMA data transfers, polling vs. blocking to check completion of communication operations, multiple VIs, completion queues and scatter capabilities of VI architecture.}, address = {Amsterdam, Netherlands}, doi = {http://dx.doi.org/10.1016/S0167-739X(01)00060-7}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/VI Architecture Communication Features and Performance on the Giganet Cluster LAN.pdf}, publisher = {Elsevier B.V.}, url = {http://www.sciencedirect.com/science/article/pii/S0167739X01000607} } @InProceedings{Csizmazia2002, author = {Csizmazia, Balázs and Hellwagner, Hermann}, booktitle = {Proceedings Fourth International Workshop on Active Middleware Services}, title = {The design and implementation of the A2QM3 System}, year = {2002}, address = {Washington, DC, USA}, editor = {N,A}, month = {jan}, pages = {19-27}, publisher = {IEEE Computer Society}, abstract = {In this paper we present the design, architecture and implementation of the A2QM3 System. It provides programmers re-usable QoS-aware Control Objects to enable building a complete middleware for adaptive applications over active networks. We introduce the programming model, the system architecture, and show the parts that make this system a full-featured middleware supporting QoS-aware reliable stream-oriented communication, communication using the request/reply-based CORBA model and real-time streaming for continuous multimedia contents.}, isbn10 = {0-7695-1721-8}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/The design and implementation of the A2QM3 System.pdf}, talktype = {none} } @InProceedings{Boeszoermenyi2002a, author = {Böszörmenyi, Laszlo and Döller, Mario and Hellwagner, Hermann and Kosch, Harald and Libsie, Mulugeta and Schojer, Peter}, booktitle = {Proceedings of the tenth ACM international conference on Multimedia}, title = {Comprehensive Treatment of Adaptation in Distributed Mulimedia Systems in the ADMITS Project}, year = {2002}, address = {New York}, editor = {Les Pins, Juan}, month = {jan}, pages = {429-430}, publisher = {ACM}, abstract = {Adaptation is becoming an increasingly important tool for resource and media management in distributed multimedia systems. Best-effort scheduling and worst-case reservation of resources are two extreme cases, none of them well suited to cope with large-scale, dynamic multimedia systems. The middle course can be met by a system which dynamically adapts its data, resource requirements, and processing components to achieve user satisfaction. Nevertheless, there is no agreement about the questions, where, when, what and who should adapt. A number of papers have been published in recent years, where adaptation is a central issue, however, in most different interpretations and generally in a somehow limited scope; e.g.,[1, 2, 8, 9, 10, 12]. A distributed multimedia system comprises several types of components, such as media servers, meta-databases, proxies, routers, clients. Also, a large number of adaptation possibilities exist, from simple frame dropping up to virtual server systems which dynamically allocate new resources on demand. The main question is, which kind of component can be best used for what kind of adaptation. In the ADMITS project (Adaptation in Distributed Multimedia IT Systems), we are seeking for answers to exactly this basic question, and to a number of related questions.}, issn = {1-58113-620-X}, language = {EN}, talktype = {none}, url = {http://portal.acm.org/citation.cfm?doid=641007.641101} } @TechReport{Ohlenroth2001, author = {Ohlenroth, Matthias and Hellwagner, Hermann}, institution = {Institute of Information Technology (ITEC), Klagenfurt University}, title = {Quality Adaptation Options of MPEG-4 Video Streams}, year = {2001}, address = {Klagenfurt, Austria}, month = dec, number = {TR/ITEC/01/1.03.}, language = {EN}, pages = {20} } @InProceedings{Kosch2001b, author = {Kosch, Harald and Böszörmenyi, Laszlo and Hellwagner, Hermann}, booktitle = {Proceedings of the 12th International Conference on Database and Expert Systems Application - DEXA 2001, Munich, Germany, September 3-5, 2001}, title = {Modeling Quality Adaptation Capabilities of Audio-Visual Data}, year = {2001}, address = {Berlin [u. a.]}, editor = {Mayr, HC and Lazansky, J and Quichmayr, G and Vogel, P}, month = sep, pages = {744-753}, publisher = {Springer Verlag}, series = {LNCS}, issn = {0302-9743}, language = {EN}, talktype = {none} } @InProceedings{Hellwagner2001a, author = {Hellwagner, Hermann and Kargl, Erich}, booktitle = {SCI 2001 Proceedings of the 5th World Multi-Conference on Systemics, Cybernetics and Informatics, Volume XV, IEEE CS, July 2001}, title = {A Cluster-Based QoS Testbed for Multimedia Communications}, year = {2001}, address = {--}, editor = {Callaos, N and Badawy, W and Bozinovski, S}, month = jul, pages = {362-367}, publisher = {IEEE}, abstract = {This paper presents an inexpensive cluster-based QoS networking testbed that can be employed to \emulate" different networks for multimedia communication ex-periments. Such a network can be built using standard PC and Ethernet hardware and open-source software components, e.g., IP routing and traÆc control avail- able in recent Linux kernels as well as a Differentiated Services package built atop these building blocks. The testbed can exibly be configured to model various link bandwidths as well as IP routers capable of classifying, queuing (with various disciplines), forward-ing and/or dropping packets and shaping traÆc. The QoS components and facilities of the testbed are in-troduced and initial performance analysis experiments and results are reported. A simple video streaming application under QoS control is presented to show the usefulness of the testbed.}, issn = {980-07-7552-8}, keywords = {multimedia communications, quality of service, QoS, networking testbed, routing, Linux}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/A Cluster-Based QoS Testbed for Multimedia Communications.pdf}, talktype = {none} } @InProceedings{Boeszoermenyi2001, author = {Böszörmenyi, Laszlo and Hellwagner, Hermann and Kosch, Harald}, booktitle = {Elektronische Geschäftsprozesse: Grundlagen, Sicherheitsaspekte, Realisierungen, Anwendungen. Tagungsband zur gemeinsamen Arbeitskonferenz GI/VOI/BITKOM/OCG/TeleTrusT}, title = {Multimedia Technologies for E-Buisness Systems and Process}, year = {2001}, address = {Höhenkirchen}, editor = {Horster, Patrick}, month = {jan}, pages = {471-481}, publisher = {it Verlag}, series = {IT Security \& IT Management}, issn = {3-936052-00-X}, language = {EN}, talktype = {none} } @Article{Weiß2000, author = {Weiß, Christian and Hellwagner, Hermann and Stals, Linda and Rüde, Ulrich}, journal = {Concepts of Numerical Software}, title = {Data Locality Optimizations to Improve The Efficiency of Multigrid Methods}, year = {2000}, month = {jan}, pages = {1-10}, abstract = {Current superscalar microprocessors are able to operate at a peak performance of up to 1 GFlop/sec. However, current main memory technology does not provide the data needed fast enough to keep the CPU busy. To minimize idle times of the CPU, caches are used to speed up accesses to frequently used data. To exploit caches, the software must be aware of them and reuse data in the cache before it is being replaced. Unfortunately, all conventional multigrid codes are not cache-aware and hence exploit less than 10 percent of the peak performance of cache based machines. Our studies with linear PDEs with constant coefficients show that it is possible to speed up the execution of our multigrid method by a large factor and hence solve a Poisson’s equation with one million unknowns in less than 3 seconds. The optimized reuse of data in the cache allows us to exploit 30 percent of the peak performance of the CPU, in contrast to mgd9v for instance, which achieves less than 5 percent on the same machine. To achieve this, we used several techniques like loop unrolling and loop fusion to better exploit the memory hierarchy and the superscalar CPU. We study the effects of these techniques on the runtime performance in detail. We also study several tools which guide the optimizations and help to restructure the code.}, address = {NA}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/10.1.1.42.3070.pdf}, publisher = {NA} } @InProceedings{Hellwagner2000b, author = {Hellwagner, Hermann and Leopold, Klaus and Schlatterbeck, Ralf and Weich, Carsten}, booktitle = {Proceedings Distributed and Parallel Systems}, title = {Performance Tuning of Parallel Real-Time Voice Communication Software}, year = {2000}, address = {Norwell, MA, USA}, editor = {Kascuk, Peter and Kotsis, Gabriele}, month = sep, pages = {57-60}, publisher = {Kluwer Academic Publishers}, abstract = {This paper describes an unconventional way to apply a performance analysis tool for parallel programs (Vampir) to understand and tune the performance of the real-time voice and data communication software running on top of Frequentis’ V4 switch. The execution schedule of the strictly time-triggered V4 switching software is computed off-line; analyzing the schedule to identify e.g. performance bottlenecks used to be a complex and time-consuming process. We present our approach to transform the V4 software schedule’s information into Vampir trace files and use this tool’s facilities to provide a visualization of the schedule. A case study illustrates the benefits of this approach.}, keywords = {This paper describes an unconventional way to apply a performance analysis tool for parallel programs (Vampir) to understand and tune the performance of the real-time voice and data communication software running on top of Frequentis’ V4 switch. The execution schedule of the strictly time-triggered V4 switching software is computed off-line; analyzing the schedule to identify e.g. performance bottlenecks used to be a complex and time-consuming process. We present our approach to transform the V4 software schedule’s information into Vampir trace files and use this tool’s facilities to provide a visualization of the schedule. A case study illustrates the benefits of this approach.}, language = {DE}, pdf = {https://www.itec.aau.at/bib/files/2000-0084-HHKL.pdf}, talktype = {none} } @InProceedings{Hellwagner2000, author = {Hellwagner, Hermann and Lachowitz, Markus and Ohlenroth, Matthias}, booktitle = {Proceedings International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA´2000), June 26, 2000, Las Vegas, Vol. 5}, title = {Exploring the Performance of VI Architecture Communication Features in the Giganet Cluster LAN}, year = {2000}, address = {[Athens, Ga.]}, editor = {Arabnia, Hamid R}, month = {jan}, pages = {2615-2621}, publisher = {CSREA Press}, abstract = {The Virtual Interface (VI) Architecture standard was developed to satisfy the need for a high-throughput, low-latency communication system required for cluster computing. This paper presents the results of a performance study of one VI Architecture hardware implementation, the Giganet cLAN (Cluster LAN). The focus of the study is to assess and compare the performance of different VI Architecture data transfer modes and specific features that are available to higher-level communication software like MPI, in order to aid the implementor to decide which VI Architecture options to employ for various communication scenarios. Examples of such options include the use of send/receive vs. RDMA data transfers, polling vs. blocking to check completion of communication operations, multiple VIs, completion queues, and scatter capabilities of VI Architecture.}, doi = {DOI:10.1016/S0167-739X(01)00060-7}, issn = {1-892512-51-3}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/2000-0079-HHML.pdf}, talktype = {none} } @Article{Hellwagner1999b, author = {Hellwagner, Hermann and Zoraja, Ivan and Sunderam, Vaidy}, journal = {Concurrency: Practice and Experience}, title = {SCIPVM: Parallel Distributed Computing on SCI Workstation Clusters}, year = {1999}, issn = {1096-9128}, month = feb, number = {No 3}, pages = {121-138}, volume = {Vol 11}, abstract = {Workstation and PC clusters interconnected by SCI (Scalable Coherent Interface) are very promising technologies for high performance cluster computing. Using commercial SBus to SCI interface cards and early system software and drivers, a two-workstation cluster has been constructed for initial testing and evaluation. The PVM system has been adapted to operate on this cluster using raw device access to the SCI interconnect, and preliminary communications performance tests have been carried out. Our preliminary results indicate that communications throughput in the range of 3.5 MBytes/s, and latencies Research supported by the Applied Mathematical Sciences program, Office of Basic Energy Sciences, U. S. Department of Energy, under Grant No. DE-FG05-91ER25105, the National Science Foundation, under Award Nos. ASC-9527186 and ASC-9214149, and the German Science Foundation SFB342. of 620 ¯s can be achieved on SCI clusters. These figures are significantly better (by a factor of 3 to 4) ...}, address = {N, A}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/10.1.1.41.2639.pdf}, publisher = {N, A} } @Book{Hellwagner1999, author = {Hellwagner, Hermann and Reinefeld, Alexander}, publisher = {Springer Verlag}, title = {SCI: Scalable Coherent Interface}, year = {1999}, address = {Berlin [u a ]}, month = {jan}, series = {LNCS}, abstract = {Architecture and Software for High-Performance Compute Clusters.}, isbn13 = {978-3-540-66696-7}, issn = {3-540-66696-6}, language = {EN}, pages = {490} } @InProceedings{Schulz1998a, author = {Schulz, Martin and Hellwagner, Hermann}, booktitle = {Proceedings of SCI-Europe ´98}, title = {Global Virtual Memory based on SCI-DSM}, year = {1998}, address = {N, A}, editor = {N, A}, month = sep, pages = {59-67}, publisher = {N, A}, language = {EN}, talktype = {none} } @InProceedings{Schulz1998, author = {Schulz, Martin and Hellwagner, Hermann}, booktitle = {Proceedings of 2nd USENIX Windows NT Symposium}, title = {Extending NT Virtual Memory by SCI-based Hardware DSM}, year = {1998}, address = {Seattle, WA, USA}, editor = {N, A}, month = aug, pages = {-}, publisher = {USENIX Association}, issn = {1-8804-4695-2}, language = {EN}, talktype = {none} } @InProceedings{Richter1998, author = {Richter, Harald and Kleber, Richard and Hellwagner, Hermann}, booktitle = {Proceedings of the High Performance Computing Symposium}, title = {Cost-Efficient SCI-based Banyan Networks}, year = {1998}, address = {N, A}, editor = {N, A}, month = apr, pages = {-}, publisher = {N, A}, keywords = {Cluster Computing, Scalable Coherent Interface, Banyan Networks}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/1998-0050-RiKH.pdf}, talktype = {none} } @Book{Gerndt1998, author = {Gerndt, Michael and Hellwagner, Hermann}, publisher = {IEEE Computer Society}, title = {Implementing Automatic Coordination on Networks of Workstations}, year = {1998}, address = {N, A}, month = mar, issn = {0-8186-8412-7}, language = {EN}, pages = {10} } @InProceedings{Eberl1998, author = {Eberl, Michael and Hellwagner, Hermann and Herland, Bjarne Geir}, booktitle = {Proceedings of HPCN-Europe 98}, title = {Common Messaging Layer for MPI and PVM over SCI}, year = {1998}, address = {NA}, editor = {Sloot, Peter and Bubak, Marian and Hertzberger, Bob}, month = apr, pages = {576-587}, publisher = {Springer Verlag}, series = {LNCS}, abstract = {This paper describes the design of a common message passing layer for implementing both MPI and PVM over the SCI interconnect in a workstation or PC cluster. The design is focused at obtaining low latency. The message layer encapsulates all necessary knowledge of the underlying interconnect and operating system. Yet, we claim that it can be used to implement such different message passing libraries as MPI and PVM without sacrificing efficiency. Initial results obtained from using the message layer in SCI clusters are presented.}, isbn13 = {978-3-540-64443-9}, language = {EN}, talktype = {none} } @Article{Mayerle1997a, author = {Mayerle, Wolfgang and Hellwagner, Hermann}, journal = {Praxis der Informationsverarbeitung und Kommunikation}, title = {Konzepte und funktionaler Vergleich von Thread-Systemen (2)}, year = {1997}, issn = {0930-5157}, month = oct, number = {4}, pages = {225-229}, volume = {20}, address = {Mannheim, Germany}, language = {DE}, publisher = {Spani} } @Article{Mayerle1997, author = {Mayerle, Wolfgang and Hellwagner, Hermann}, journal = {Praxis der Informationsverarbeitung und Kommunikation}, title = {Konzepte und funktionaler Vergleich von Thread-Systemen (1)}, year = {1997}, issn = {0930-5157}, month = {jan}, pages = {164-174}, volume = {20}, abstract = {Dieses Papier gibt eine allgemeine Einführung in Threads und vergleicht einige derzeit für Arbeitsplatzrechner erhältliche Thread-Systeme. Aufbauend auf einer Motivation und grundlegenden Erläuterung des Thread-Konzepts werden wichtige Aspekte und Probleme von Thread-Bibliotheken vorgestellt. Nach einigen Hinweisen zur Programmierung mit Threads werden mehrere Implementierungen einander gegenübergestellt.}, address = {Mannheim, Germany}, language = {DE}, pdf = {https://www.itec.aau.at/bib/files/1997-0048-MaHe.pdf}, publisher = {Spaniol, Otto} } @InProceedings{Hellwagner1997f, author = {Hellwagner, Hermann}, booktitle = {Informatik-Handbuch}, title = {Arbeitsspeicher- und Bussysteme}, year = {1997}, address = {München}, editor = {Rechenberg, Peter and Pomberger, Gustav}, month = sep, pages = {239-255}, publisher = {Carl Hanser Verlag}, issn = {3-446-18691-3}, language = {DE}, talktype = {none} } @Article{Hellwagner1997e, author = {Hellwagner, Hermann and Karl, Wolfgang and Leberecht, Markus}, journal = {Speedup Journal, Proceedings, 21st Workshop, March 13-14, 1997, Cadro-Lugano}, title = {Enabling a PC Cluster for High-Performance Computing}, year = {1997}, month = jun, number = {1}, pages = {18-23}, volume = {Vol. 11}, abstract = {Due to their excellent cost/performance ratio, clusters of PCs can be attractive high-performance computing (HPC) platforms. Yet, their limited communication performance over standard LANs is still prohibitive for parallel applications. The project "Shared Memory in a LAN-like Environment" (SMiLE) at LRR-TUM adopts Scalable Coherent Interface (SCI) interconnect technology to build, and provide software for, a PC cluster which, with hardware-based distributed shared memory (DSM) and high-performance communication characteristics, is regarded as well suited for HPC. The paper describes the key features of the enabling technology, SCI. It then discusses the developments and important results of the SMiLE project so far: the development and initial performance of a PCI/SCI interface card, and the design and initial performance results of low-latency communication layers, Active Messages and a sockets emulation library.}, address = {N, A}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/1997-0049-HeKL.pdf}, publisher = {N, A} } @Book{Hellwagner1997c, author = {Hellwagner, Hermann}, publisher = {IEEE Computer Society}, title = {High-Level Programming Models and Supportive Environments (HIPS'97)}, year = {1997}, address = {Los Alamitos, CA}, month = apr, issn = {0-8186-7792-9}, language = {EN}, pages = {900} } @Book{Hellwagner1997b, author = {Hellwagner, Hermann}, publisher = {IEEE}, title = {Proceedings Second International Workshop on High-Level Parallel Programming Models and Supportive Environments}, year = {1997}, address = {N, A}, month = apr, series = {Computer}, language = {EN}, pages = {135} } @InProceedings{Hellwagner1997, author = {Hellwagner, Hermann and Karl, Wolfgang and Leberecht, Markus}, booktitle = {Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications, 1997: PDPTA}, title = {Fast Communication Mechanisms--Coupling Hardware Distributed Shared Memory and User-Level Messaging}, year = {1997}, address = {Las Vegas, Nevada, USA}, editor = {Arabnia, Hamid R}, month = {jan}, pages = {8}, publisher = {CSREA Press}, abstract = {Low latencies for small messages are an important factor of efficient fine-grained parallel computation. The Active Messages concept provides this minimal overhead by eliminating certain parts of the critical path of sending and receiving messages, that is the context switch into the operating system kernel when using user-mode I/O, and multiple buffering in the network layer. Hardware-supported distributed shared memory (DSM) architectures exhibit various properties that make them particularly useful for an implementation of the aforementioned messaging mechanisms. This paper thus describes the concept, implementation, and the performance of a DSM-based Active Messages layer.}, issn = {0-9648666-8-4}, keywords = {Distributed Shared Memory, Active Messages, User-Level Communication, Scalable Coherent Interface}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/1997-0047-HeLe.pdf}, talktype = {none} } @InProceedings{Eberl1997c, author = {Eberl, Michael and Hellwagner, Hermann and Herland, Bjarne Geir and Schulz, Martin}, booktitle = {Tagungsband zum 1. Workshop Cluster Computing}, title = {SISCI - Implementing a Standard Software Infrastructure on an SCI Cluster}, year = {1997}, address = {N, A}, editor = {Rehm, Wolfgang}, month = nov, pages = {49-61}, publisher = {N, A}, series = {Chemnitzer-Informatik-Berichte}, abstract = {To enable the efficient utilization of clusters of workstations it is crucial to develop a stable and rich software infrastructure. The ESPRIT Project SISCI will provide two widely used message-passing interfaces, MPI and PVM, as well as a POSIX compliant, distributed thread package (Pthreads) on multiple SCI-based clusters. This paper features motivation and background on this projects as well as details of the two core components: the common messaging layer and the Pthreads package.}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/10.1.1.39.9157.pdf}, talktype = {none} } @InProceedings{Eberl1997b, author = {Eberl, Michael and Hellwagner, Hermann and Karl, Wolfgang and Leberecht, Markus}, booktitle = {Architektur von Rechensystemen: Arbeitsteilige Systemarchitekturen - Konzepte, Lösungen, Anwendungen, Trends (ARCS´97)}, title = {Sicherheit und Effizienz in einer Active-Message-Kommunikationsschicht}, year = {1997}, address = {N, A}, editor = {Tavangarian, Djamshid}, month = sep, pages = {-}, publisher = {VDE Verlag}, series = {Vorträge der 14. ITG/GI Fachtagung ARCS}, abstract = {Active Messages haben sich als effizientes Kommunikationsverfahren insbesondere auf Kommunikationstechnologien durchgesetzt, die einen direkten Zugriff des Benutzers ohne Intervention des Betriebssystems zulassen. Als Nachteil der leichtgewichtigen Kommunikation erwiesen sich jedoch die nicht ausreichenden Schutzmechanismen, vor allem bei der Verwendung mehrerer Prozesse, die sich gleichzeitig einer Active-Message-Bibliothek bedienen. Die Spezifikation 2.0 der Berkeley-Active-Messages unternimmt nun den Versuch, f¨ur das bekannte und schnelle Kommunikationsverfahren Schutzabstraktionen vorzusehen. Im Rahmen dieser Arbeit wird die Implementation eines solchen Active-Message-Layers der Version 2.0 auf einem Cluster von SCI-gekoppelten Arbeitsplatzrechnern beschrieben. Wir k¨onnen zeigen, daß die zus¨atzlichen Schutzmechanismen nur wenig Einfluß auf die Leistung haben und somit der Vorteil der Active Messages, die leichtgewichtige, feingranulare Kommunikation, erhalten bleibt.}, issn = {3-8007-2295-X}, language = {DE}, pdf = {https://www.itec.aau.at/bib/files/1997-0043-EbHL.pdf}, talktype = {none} } @InProceedings{Eberl1997a, author = {Eberl, Michael and Hellwagner, Hermann and Karl, Wolfgang and Leberecht, Markus}, booktitle = {Architektur von Rechensystemen, Arbeitsteilige Systemarchitekturen: Konzepte, Lösungen, Anwendungen, Trends - Vorträge der 14. ITG/GI-Fachtagung ARCS '97}, title = {Sicherheit und Effizienz in einer Active Message-Kommunikationsschicht}, year = {1997}, address = {N, A}, editor = {Tavangarian, Djamshid}, month = {jan}, pages = {211-220}, publisher = {VDE Verlag}, abstract = {Active Messages haben sich als effizientes Kommunikationsverfahren insbesondere auf Kommunikationstechnologien durchgesetzt, die einen direkten Zugriff des Benutzers ohne Intervention des Betriebssystems zulassen. Als Nachteil der leichtgewichtigen Kommunikation erwiesen sich jedoch die nicht ausreichenden Schutzmechanismen, vor allem bei der Verwendung mehrerer Prozesse, die sich gleichzeitig einer Active-Message- Bibliothek bedienen. Die Spezifikation 2.0 der Berkeley-Active-Messages unternimmt nun den Versuch, für das bekannte und schnelle Kommunikationsverfahren Schutzabstraktionen vorzusehen. Im Rahmen dieser Arbeit wird die Implementation eines solchen Active- Message-Layers der Version 2.0 auf einem Cluster von SCI-gekoppelten Arbeitsplatzrechnern beschreiben. Wir können zeigen, daß die zusätzlichen Schutzmechanismen nur wenig Einfluß auf die Leistung haben und somit der Vorteil der Active Messages, die leichtgewichtige, feingranulare Kommunikation, erhalten bleibt.}, issn = {3-8007-2295-X}, language = {DE}, talktype = {none} } @InProceedings{Acher1997, author = {Acher, Georg and Hellwagner, Hermann and Karl, Wolfgang and Leberecht, Markus}, booktitle = {Arbeitsplatz-Rechensysteme: Anwendungen, Architekturen, Betriebssysteme und Netzwerke}, title = {Eine PCI-SCI-Adapterkarte für ein PC-Cluster mit verteiltem gemeinsamen Speicher}, year = {1997}, address = {N, A}, editor = {N, A}, month = {jan}, pages = {-}, publisher = {N, A}, issn = {3-9235-3261-X}, language = {DE}, talktype = {none} } @InProceedings{Hellwagner1996, author = {Hellwagner, Hermann and Zoraja, Ivan and Sunderam, Vaidy}, booktitle = {Proceedings PVM User Group Meeting}, title = {PVM Data Transfers on SCI Workstation Clusters}, year = {1996}, address = {N, A}, editor = {Bode, Arndt and Dongarra, Jack and Ludwig, Thomas and Sunderam, Vaidy}, month = feb, pages = {-}, publisher = {Springer}, language = {EN}, talktype = {none} } @Article{Boeckle1996a, author = {Böckle, Günter and Hellwagner, Hermann and Lepold, Roland and Sandweg, Gerd and Schallenberger, Burghardt and Thudt, Raimar and and Wallstab, Stefan}, journal = {IEEE Computer Society}, title = {Structured Evaluation of Computer Systems}, year = {1996}, issn = {0018-9162}, month = jun, number = {No 6}, pages = {45-51}, volume = {Vol. 29}, abstract = {Evaluating computers and other systems is difficult for a couple of reasons. First, the goal of evaluation is typically ill-defined: customers, sometimes even designers, either don't know or can't specify exactly what result they expect. Often, they don't specify the architectural variants to consider, and often the metrics and workload they expect you to use are ill-defined. Second, they rarely clarify which kind of model and evaluation method best suit the evaluation problem. These problems have consequences. For one thing, the decision-maker may not trust the evaluation. For another, poor planning means the evaluation cannot be reproduced if any of the parameters are changed slightly. Finally, the evaluation documentation is usually inadequate, and so some time after the evaluation you might ask yourself, how did I come to that conclusion? An approach developed at Siemens makes decisions explicit and the process reproducible}, address = {N, A}, doi = {http://dx.doi.org/10.1109/2.507631}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/00507631.pdf}, publisher = {N, A} } @InProceedings{Bode1996a, author = {Bode, Arndt and Gerndt, Michael and Hackenberg, R and Hellwagner, Hermann}, booktitle = {Proceedings of IPPS '96, The 10th International Parallel Processing Symposium}, title = {High-Level Programming Models and Supportive Environments (HIPS´96)}, year = {1996}, address = {N, A}, editor = {N, A}, month = apr, pages = {-}, publisher = {IEEE Computer Society}, issn = {0-8186-7255-2}, language = {EN}, talktype = {none} } @Book{Bode1996, author = {Bode, Arndt and Gerndt, Michael and Hackenberg, R G and Hellwagner, Hermann}, publisher = {IEEE Computer Society Press}, title = {Proceedings First International Workshop on High-Level Parallel Programming Models and Supportive Environments}, year = {1996}, address = {NA}, month = {jan}, issn = {0-8186-7567-5}, language = {EN}, pages = {128} } @InProceedings{Boeckle1994, author = {Böckle, Günter and Hellwagner, Hermann}, booktitle = {Innovationen bei Rechen- und Kommunikationssystemen, Eine Herausforderung für die Informatik}, title = {Systematic Assessment of Computer Systems Architectures}, year = {1994}, address = {N, A}, editor = {Wolfinger, Bernd E}, month = aug, pages = {310-317}, publisher = {Springer Verlag}, issn = {3-5405-8313-0}, language = {EN}, talktype = {none} } @InProceedings{Hellwagner1993a, author = {Hellwagner, Hermann}, booktitle = {Parallel Computer Architectures: Theory, Hardware, Software, Applications}, title = {Randomized Shared Memory - Concept and Efficiency of a Scalable Shared Memory Scheme}, year = {1993}, address = {London, UK}, editor = {Arndt, Bode and Dal Cin, Mario}, month = {jan}, pages = {102-117}, publisher = {Springer Verlag}, series = {LNCS}, abstract = {Our work explores the practical relevance of Randomized Shared Memory (RSM), a theoretical concept that has been proven to enable an (asymptotically) optimally efficient implementation of scalable and universal shared memory in a distributed-memory parallel system. RSM (address hashing) pseudo-randomly distributes global memory addresses throughout the nodes' local memories. High memory access latencies are masked through massive parallelism. This paper introduces the basic principles and properties of RSM and analyzes its practical efficiency in terms of constant factors through simulation studies, assuming a state-of-the-art parallel architecture. Bottlenecks in the architecture are pointed out, and improvements are being made and their effects assessed quantitatively. The results show that RSM efficiency is encouragingly high, even in a non-optimized architecture. We propose architectural features to support RSM and conclude that RSM may indeed be a feasible shared-memory implementation in future massively parallel computers.}, issn = {3-540-57307-0}, language = {EN}, talktype = {none} } @Article{Hellwagner1993, author = {Hellwagner, Hermann}, journal = {The Computer Journal - Parallel Processing}, title = {Design Considerations for Scalable Parallel File Systems}, year = {1993}, month = {jan}, number = {8}, pages = {741-755}, volume = {Vol. 36}, abstract = {This paper addresses the problem of providing high-performance disk I/O in massively parallel computers. Resolving the fundamental I/O bottleneck in parallel architectures involves both hardware and software issues. We review previous work on disk arrays and I/O architectures aimed at providing highly parallel disk I/O subsystems. We then focus on the requirements and design of parallel file systems (PFSs) which are responsible to make the parallelism offered by the hardware and a declustered file organization available to application programs. We present the design strategy and key concepts of a general-purpose file system for a parallel computer with scalable distributed shared memory. The principal objectives of the PFS are to fully exploit the parallelism inherent among and within file accesses, and to provide scalable I/O performance. The machine model underlying the design is described, with and emphasis on the innovative architectural features supporting scalability of the shared memory. Starting from a classification of various scenarios of concurrent I/O requests, the features of the PFS design essential for achieving the goals are described and justified. It is argued that the inter- and intra-request parallelism of the I/O load can indeed be effectively exploited and supported by the parallel system resources. Scalability of I/O performance and of the PFS software can be ensured by avoiding serial bottlenecks through the use of the powerful architectural features.}, address = {N, A}, language = {EN}, pdf = {https://www.itec.aau.at/bib/files/741.full.pdf}, publisher = {N, A} } @InProceedings{Hellwagner1992, author = {Hellwagner, Hermann}, booktitle = {Parallel Processing: CONPAR 92 - VAPP V, Second Joint International Conference on Vector and Parallel Processing}, title = {On the Practical Efficiency of Randomized Shared Memory}, year = {1992}, address = {Berlin-Heidelberg}, editor = {Bougé, Luc and Cosnard, Michel and Robert, Yves and Trystram, Denis}, month = sep, pages = {429-440}, publisher = {Springer}, series = {LNCS}, abstract = {This paper analyzes the efficiency of Randomized Shared Memory (RSM) in terms of constant factors. RSM or memory hashing, that is, pseudorandom distribution of global memory addresses throughout local memories in a distributed-memory parallel system, has been proven to enable an (asymptotically) optimally efficient implementation of scalable and universal shared memory. High memory access latencies are hidden through massive parallelism. Our work examines the practical relevance and feasibility of this potentially significant theoretical result. After an introduction of the background, principles, and desirable properties of RSM and an outline of the approach to determine RSM efficiency, the major results of our simulations are presented. The results show that RSM efficiency is encouragingly high (up to 20% efficiency of idealized shared memory), even in an architecture modelled on the basis of state-of-the-art technology. Performance-limiting factors are identified from the results and architectural features to increase efficiency are proposed, most notably extremely fast process switching and a combining network. Several novel machine designs document the increased interest in RSM and hardware support.}, issn = {3-540-55895-0}, language = {EN}, talktype = {none} } @Book{Hellwagner1989, editor = {Hellwagner, Hermann}, publisher = {VWGO}, title = {Systolische Architekturen für die Verallgemeinerte Diskrete Fourier-Transformation}, year = {1989}, address = {Wien}, month = {jan}, isbn10 = {385369733x}, isbn13 = {978-3853697337}, language = {DE}, pages = {150} }