[223] | Harald Beck, Bruno Bierbaumer, Minh Dao-Tran, Thomas Eiter, Hermann Hellwagner, Konstantin Shekotihin, Rule-based Stream Reasoning for Intelligent Administration of Content-Centric Networks, In Proceedings of 15th European Conference on Logics in Artificial Intelligence (JELIA) 2016 (Loizos Michael, Antonis C Kakas, eds.), Springer, Cyprus, pp. 522-528, 2016.
[bib] [doi] [abstract]
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Content-Centric Networking (CCN) research addresses the mismatch between the modern usage of the Internet and its outdated architecture.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.
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[222] | Christian Kreuzberger, Benjamin Rainer, Hermann Hellwagner, Laura Toni, Pascal Frossard, A Comparative Study of DASH Representation Sets Using Real User Characteristics, In Proceedings of the 26th International Workshop on Network and Operating Systems Support for Digital Audio and Video (ACM, ed.), ACM, New York, NY, USA, pp. 4:1-4:6, 2016.
[bib] |
[221] | Evsen Yanmaz, Markus Quaritsch, Saeed Yahyanejad, Bernhard Rinner, Hermann Hellwagner, Christian Bettstetter, Communication and Coordination for Drone Networks, In Proceedings of the EAI International Conference on Ad Hoc Networks (ADHOCNETS) (Zhou Yifeng, Kunz Thomas, eds.), Springer Verlag, Ottawa, Canada, pp. 79-91, 2016.
[bib][url] [doi] [pdf] [abstract]
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.
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[220] | Adrian Sterca, Hermann Hellwagner, Florian Boian, Alexandru Vancea, Media-friendly and TCP-friendly Rate Control Protocols for Multimedia Streaming, In IEEE Transactions on Circuits and Systems for Video Technology, IEEE, vol. 1, no. 1, USA, pp. 15, 2015.
[bib][url] [doi] [abstract]
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.
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[219] | Jürgen Scherer, Saeed Yahyanejad, Samira Hayat, Evsen Yanmaz, Torsten Andre, Asif Khan, Vladimir Vukadinovic, Christian Bettstetter, Hermann Hellwagner, Bernhard Rinner, An Autonomous Multi-UAV System for Search and Rescue, In Proceedings of the First Workshop on Micro Aerial Vehicle Networks, Systems, and Applications for Civilian Use (Kuan-Ta Chen, Mario Gerla, Karin Anna Hummel, Claudio Palazzi, Sofie Pollin, James JP Sterbenz, eds.), ACM, New York, USA, pp. 33-38, 2015.
[bib][url] [doi] [abstract]
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.
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[218] | Benjamin Rainer, Stefan Petscharnig, Christian Timmerer, Hermann Hellwagner, Is One Second Enough? - Evaluating QoE for Inter-Destination Multimedia Synchronization using Human Computation and Crowdsourcing, In Seventh International Workshop on Quality of Multimedia Experience (QoMEX 2015) (Athanassios Skodras, ed.), IEEE, Greece, Messinia, pp. 1-6, 2015.
[bib] [pdf] [abstract]
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.
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[217] | Christian Raffelsberger, Hermann Hellwagner, A Multimedia Delivery System for Delay-/Disruption-Tolerant Networks, In Proceedings of the 13th IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops '15) (Ali Hurson, Sajal K Das, eds.), IEEE, Los Alamitos, CA, USA, pp. 530-536, 2015.
[bib] [doi] [pdf] [abstract]
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.
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[216] | Daniela Pohl, Abdelhamid Bouchachia, Hermann Hellwagner, Online Indexing and Clustering of Social Media Data for Emergency Management, In Neurocomputing, Elsevier, Amsterdam, Netherlands, pp. 168-179, 2015.
[bib] [doi] [abstract]
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.
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[215] | Christian Kreuzberger, Benjamin Rainer, Hermann Hellwagner, Modelling the Impact of Caching and Popularity on Concurrent Adaptive Multimedia Streams in Information-Centric Networks, In IEEE International Conference on Multimedia Expo Workshops (Cesana Matteo, ed.), IEEE, Los Alamitos, CA, USA, pp. 1-6, 2015.
[bib] [doi] [pdf] [abstract]
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.
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[214] | Christian Kreuzberger, Daniel Posch, Hermann Hellwagner, A Scalable Video Coding Dataset and Toolchain for Dynamic Adaptive Streaming over HTTP, In Proceedings of the 6th ACM Multimedia Systems Conference (Tsang Ooi Wei, ed.), ACM, New York, NY, USA, pp. 213-218, 2015.
[bib][url] [doi] [pdf] [abstract]
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.
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[213] | Hermann Hellwagner, Severin Kacianka, Adaptive Video Streaming for UAV Networks, In MoVid '15 Proceedings of the 7th ACM International Workshop on Mobile Video (Pal Halvorsen, Nikil Dutt, eds.), ACM International Conference on Multimedia Systems, New York, USA, pp. 25-30, 2015. (to appear)
[bib] [doi] [abstract]
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.
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[212] | Florian Bacher, Benjamin Rainer, Hermann Hellwagner, Towards Controller-aided Multimedia Dissemination in Named Data Networking, In Proceedings of IEEE International Conference on Multimedia and Expo Workshops (available not, ed.), IEEE, Los Alamitos, CA, USA, pp. 1-6, 2015.
[bib] [doi] [pdf] [abstract]
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.
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[211] | Christian Timmerer, Markus Waltl, Benjamin Rainer, Stefan Lederer, Hermann Hellwagner, Enhancing 3D Video to enable a Fully Immersive Sensory Experiences, In IEEE Multimedia Communications Technical Committee E-Letter, IEEE Communications Society [online], vol. 9, no. 1, New York, NY, USA, pp. 23-26, 2014.
[bib][url] [pdf] |
[210] | Christian Raffelsberger, Hermann Hellwagner, Combined Mobile Ad-Hoc and Delay/Disruption-Tolerant Routing, In Proceedings of the 13th International Conference on Ad-hoc, Mobile, and Wireless Networks (ADHOC-NOW '14) (Song Guo, Pietro Manzoni, Jaime Lloret, Stefan Ruehrup, eds.), Springer, vol. 8487, Berlin Heidelberg, pp. 1-14, 2014.
[bib] [pdf] |
[209] | Daniel Posch, Christian Kreuzberger, Benjamin Rainer, Hermann Hellwagner, Using In-Network Adaptation to Tackle Inefficiencies Caused by DASH in Information-Centric Networks, In Proceedings of the 10th International Conference on Emerging Networking Experiments and Technologies, VideoNext Workshop (Colin Dixon, ed.), ACM Digital Library, New York, NY, USA, pp. 1-6, 2014.
[bib] [pdf] [abstract]
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.
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[208] | Daniel Posch, Christian Kreuzberger, Benjamin Rainer, Hermann Hellwagner, Client Starvation: A Shortcoming of Client-driven Adaptive Streaming in Named Data Networking, In Proceedings of the 1st ACM Conference on Information-Centric Networking (Paulo Mendes, ed.), ACM Digital Library, New York, NY, USA, pp. 1-2, 2014. (to appear)
[bib][url] [doi] [pdf] [abstract]
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.
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[207] | Daniela Pohl, Abdelhamid Bouchachia, Hermann Hellwagner, Crisis-related Sub-Event Detection Based on Clustering, In E-Letter on Social Media Analysis for Crisis Management, IEEE Computer Society Special Technical Community on Social Networking (STCSN), vol. 2, no. 1, http://stcsn.ieee.net/e-letter/vol-2-no-1, pp. 1-10, 2014, IEEE Computer Society Special Technical Community on Social Networking E-Letter.
[bib][url] |
[206] | Stefan Lederer, Christopher Mueller, Christian Timmerer, Hermann Hellwagner, Adaptive Multimedia Streaming in Information-Centric Networks, In IEEE Network, IEEE, vol. 28, no. 6, IEEE Communications Society, pp. 91-96, 2014.
[bib] [abstract]
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.
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[205] | Torsten Andre, Karin Anna Hummel, Angela Schoellig, Evsen Yanmaz, Mahdi Asadpour, Christian Bettstetter, Pasquale Grippa, Hermann Hellwagner, Stephan Sand, Siwei Zhang, Application-Driven Design of Aerial Communication Networks, In IEEE Communications Magazine, IEEE, vol. 52, no. 5, IEEE Communications Society, pp. 129-137, 2014.
[bib] [abstract]
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.
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[204] | Hermann Hellwagner, The BRIDGE Project - Bridging Resources and Agencies in Large-Scale Emergency Management, In E-Letter on Social Media Analysis for Crisis Management, IEEE Computer Society Special Technical Community on Social Networking (STCSN), vol. 2, no. 1, http://stcsn.ieee.net/e-letter/vol-2-no-1, pp. 1-10, 2014, IEEE Computer Society Special Technical Community on Social Networking E-Letter.
[bib][url] [abstract]
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.
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[203] | Hermann Hellwagner, The Interplay of Technology Development and Media Convergence: Examples, Chapter in Media and Convergence Management (Sandra Diehl, Matthias Karmasin, eds.), Springer, Berlin, Heidelberg, New York, pp. 205-220, 2013.
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[202] | Markus Waltl, Benjamin Rainer, Christian Timmerer, Hermann Hellwagner, An End-to-End tool chain for sensory experience based on MPEG-V, In Signal Processing: Image Communication, Elsevier, vol. 28, no. 2, Amsterdam, Netherlands, pp. 136-150, 2013.
[bib][url] [doi] [abstract]
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.
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[201] | Tibor Szkaliczki, Michael Eberhard, Hermann Hellwagner, László Szobonya, Piece selection algorithms for layered video streaming in P2P networks, In Discrete Applied Mathematics, Elsevier, Amsterdam, The Netherlands, pp. 11, 2013.
[bib][url] |
[200] | Christian Raffelsberger, Hermann Hellwagner, A Hybrid MANET-DTN Routing Scheme For Emergency Response Scenarios, In Proceedings of the Eleventh IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops '13) (Jadwiga Indulska, Chatschik Bisdikian, eds.), IEEE, Los Alamitos, CA, USA, pp. 505-510, 2013.
[bib] [pdf] [abstract]
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.
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[199] | Christian Raffelsberger, Hermann Hellwagner, Overview of Hybrid MANET-DTN Networking and its Potential for Emergency Response Operations, In Proceedings of the Combined workshop on Self-organizing, Adaptive, and Context-Sensitive Distributed Systems and Self-organized Communication in Disaster Scenarios (SACS/SoCoDiS '13) (Michael Zapf, Florian Evers, eds.), Electronic Communications of the EASST (ECEASST), Berlin, Germany, pp. 1 -12, 2013.
[bib] [pdf] [abstract]
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.
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