[98] | Michael Eberhard, Luca Celetto, Christian Timmerer, Emanuele Quacchio, Hermann Hellwagner, Performance Analysis of Scalable Video Adaptation: Generic versus Specific Approach, In 2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services (Hermann Hellwagner, Christian Timmerer, eds.), IEEE, Los Alamitos, CA, USA, pp. 43-50, 2008.
[bib] [pdf] [abstract]
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
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[97] | Raffaele Bolla, Matteo Repetto, Stefano Chessa, Francecso Furfari, Saar De Zutter, Rik Van de Walle, Bernhard Reiterer, Hermann Hellwagner, Mark Asbach, Mathias Wien, A Context-Aware Architecture for QoS and Transcoding Management of Multimedia Streams in Smart Homes, In 13th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA08) (Industrial Electronics Society IEEE, ed.), IEEE, Los Alamitos, CA, USA, pp. 1354-1361, 2008.
[bib] [pdf] [abstract]
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.
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[96] | Davy Van Deursen, Sarah De Bruyne, Wim Van Lancker, Wesley De Neve, Davy De Schrijver, Hermann Hellwagner, Rik Van de Walle, MuMiVA: A Multimedia Delivery Platform using Format-agnostic, XML-driven Content Adaptation, In IEEE International Symposium on Multimedia 2007 (ISM2007) (Dick Bulterman, Kinji Mori, Jeffrey J P Tsai, eds.), IEEE, Los Alamitos, CA, USA, pp. 131-138, 2007.
[bib][url] [pdf] [abstract]
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.
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[95] | Michael Ransburg, Christian Timmerer, Hermann Hellwagner, Sylvain Devillers, Design and Evaluation of a Metadata-Driven Adaptation Node, In WIAMIS 2007 (Yiannis Kompatsiaris, Yannis Avrithis, eds.), IEEE, Los Alamitos, CA, USA, pp. 4, 2007.
[bib][url] [pdf] [abstract]
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.
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[94] | Michael Ransburg, Sylvain Devillers, Christian Timmerer, Hermann Hellwagner, Processing and Delivery of Multimedia Metadata for Multimedia Content Streaming, In Datenbanksysteme in Business, Technologie und Web (BTW 2007) (Matthias Jarke, Thomas Seidl, Christoph Quix, David Kensche, St Conrad, E Rahm, Ralf Klamma, Harald Kosch, Michael Granitzer, S Apel, M Rosenmüller, Gunter Saake, Olaf Spinczyk, eds.), Verlag Mainz, Aachen, pp. 117-138, 2007.
[bib] [pdf] [abstract]
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.
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[93] | Martin Prangl, Roland Bachlechner, Hermann Hellwagner, A hybrid recommender strategy for personalized utility-based cross-modal multimedia adaptation, In 2007 IEEE International Conference on Multimedia and Expo (ICME 2007) (Xinhua Zhuang, Wen Gao, eds.), IEEE, Los Alamitos, CA, USA, pp. 1707-1710, 2007.
[bib] [pdf] [abstract]
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.
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[92] | Martin Prangl, Tibor Szkaliczki, Hermann Hellwagner, A Framework for Utility-Based Multimedia Adaptation, In IEEE Transactions on Circuits and Systems for Video Technology, IEEE, vol. 17/2007, no. 6, Los Alamitos, CA, USA, pp. 719-728, 2007.
[bib] [pdf] [abstract]
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.
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[91] | Martin Prangl, Hermann Hellwagner, A framework for personalized utility-aware IP-based multimedia consumption, In World of Wireless, Mobile and Multimedia Networks, 2007. WoWMoM 2007 (Eric Fleury, Holger Karl, eds.), IEEE, Los Alamitos, CA, USA, pp. 1-3, 2007.
[bib][url] [pdf] [abstract]
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.
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[90] | Phivos Mylonas, Manolis Wallace, Marios C Angelides, Hermann Hellwagner, Harry Agius, Second International Workshop on Semantic Media Adaptation and Personalization (SMAP 2007), IEEE, Los Alamitos, CA, USA, pp. 269, 2007.
[bib][url] |
[89] | Janine Lachner, Andreas Lorenz, Bernhard Reiterer, Andreas Zimmermann, Hermann Hellwagner, Challenges toward User-centric Multimedia, In Second International Workshop on Semantic Media Adaptation and Personalization (SMAP 2007) (Phivos Mylonas, Manolis Wallace, Marios C Angelides, eds.), IEEE, Los Alamitos, CA, USA, pp. 159-164, 2007.
[bib][url] [pdf] [abstract]
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.
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[88] | Michael Kropfberger, Roland Tusch, Michael Jakab, Julius Köpke, Michael Ofner, Hermann Hellwagner, Laszlo Böszörmenyi, A Multimedia-Based Guidance System for various Consumer Devices, In Proceedings of the 3rd International Conference on Web Information Systems and Technologies (WEBIST '07) (Joaquim Filipe, José Cordeiro, eds.), INSTICC Press, Setubal, Portugal, pp. 83-90, 2007.
[bib][url] [pdf] [abstract]
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.
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[87] | Ingo Kofler, Christian Timmerer, Toufik Ahmed, Hermann Hellwagner, Towards MPEG-21-based Cross-layer Multimedia Content Adaptation, In Proceedings of the Second International Workshop on Semantic Media Adaptation and Personalization (SMAP) (Phivos Mylonas, Manolis Wallace, Marios C Angelides, eds.), IEEE, Los Alamitos, CA, USA, pp. 3-8, 2007.
[bib] [doi] [pdf] [abstract]
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.
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[86] | Michael Jakab, Michael Kropfberger, Michael Ofner, Roland Tusch, Hermann Hellwagner, Laszlo Böszörmenyi, Metadata Integration and Media Transcoding in Universal-Plug-and-Play (UPnP) Enabled Networks, In Proceedings of the 15th Euromicro Conference on Parallel, Distributed and Network-based Processing (Pasqua D'Ambra, Mario R Guarracino, eds.), IEEE, Los Alamitos, CA, USA, pp. 363 - 369, 2007.
[bib] [pdf] [abstract]
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.
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[85] | Laszlo Böszörmenyi, Hermann Hellwagner, Peter Schojer, Metadata-driven optimal transcoding in a multimedia proxy, In Multimedia Systems, Springer, vol. Vol. 13, no. Issue 1, Berlin, Heidelberg, New York, pp. 51-68, 2007.
[bib] [doi] [pdf] [abstract]
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.
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[84] | Christian Timmerer, Thomas DeMartini, Hermann Hellwagner, The MPEG-21 Multimedia Framework: Conversions and Permissions, In D A CH Security 2006 (Patrick Horster, ed.), IT Security & IT Management, Düsseldorf, pp. 225-235, 2006.
[bib] [pdf] [abstract]
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.
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[83] | Peter Schojer, Laszlo Böszörmenyi, Hermann Hellwagner, QBIX-G- A Transcoding Multimedia Proxy, In Multimedia Computing and Networking 2006 (Surendar Chandra, Carsten Griwodz, eds.), SPIE, San Jose, pp. 60710C-1 - 60710C-16, 2006.
[bib] [abstract]
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.
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[82] | Peter Schojer, Laszlo Böszörmenyi, Hermann Hellwagner, QBIX-G-A Transcoding Multimedia Proxy, Technical report, Institute of Information Technology (ITEC), Klagenfurt University, no. TR/ITEC/05/2.11, Klagenfurt, Austria, pp. 24, 2006.
[bib] [abstract]
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.
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[81] | Martin Santner, Roland Tusch, Michael Kropfberger, Laszlo Böszörmenyi, Hermann Hellwagner, Ein Ortserkennungssystem für mobile Touristenführer, In D•A•CH Mobility 2006 (Patrick Horster, ed.), IT Security & IT Management, Ottobrunn, München, Deutschland, pp. 84-98, 2006.
[bib] [abstract]
Abstract: - Location-Based Services - Ortserkennungstechnologien - Ortserkennungsmiddleware - Integration in mobile Anwendung - Automatisiertes Führungssystem.
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[80] | Michael Ransburg, Renaud Cazoulat, Benoit Pellan, Cyril Concolato, Saar De Zutter, Chris Poppe, Andreas Hutter, Hermann Hellwagner, Rik Van de Walle, Dynamic and Distributed Adaptation of Scalable Multimedia Content in a Context-Aware Environment, In Proc. of the European Symposium on Mobile Media Delivery (EuMob 2006) (2006 EuMob, ed.), --, Alghero, Italy, pp. 1-5, 2006.
[bib] [pdf] [abstract]
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.
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[79] | Martin Prangl, Hermann Hellwagner, Tibor Szkaliczki, Fast adaptation decision taking for cross-modal multimedia content adaptation, In Proceedings oft the IEEE International Conference on Multimedia and Expo (ICME) (Guan Ling, Zhang Hong-Jiang, eds.), IEEE Press, Toronto, Canada, pp. 137-140, 2006.
[bib] [pdf] [abstract]
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.
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[78] | Martin Prangl, Christian Timmerer, Hermann Hellwagner, Real-time DVB based MPEG-21 Digital Item Adaptation for live Universal Multimedia Access, In Proceedings ELMAR 2006 (Mislav Grgic, Sonja Grgic, eds.), Croatian Society Electronics in Marine - ELMAR, Zadar, Zadar, pp. 297-300, 2006.
[bib] [pdf] [abstract]
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.
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[77] | Martin Prangl, Hermann Hellwagner, Tibor Szkaliczki, A Semantic-based Multi-modal Utility Approach For Multimedia Adaptation, In Proceedings of the 7th International Workshop on Image Analysis for Multimedia Services (WIAMIS) (Izquierdo Ebroul, Kim Hyoung Joon, eds.), WIAMIS Eigenverlag, Incheon, Korea, pp. 67-70, 2006.
[bib] [pdf] [abstract]
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.
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[76] | Martin Prangl, Hermann Hellwagner, Horst Bischof, Tibor Szkaliczki, Realtime automatic metal extraction of medical x-ray images for contrast improvement, In Proceedings of the SPIE Symposium on Medical Imaging 2006 (Joseph M Reinhardt, Josien P W Pluim, eds.), SPIE, San Diego, pp. 8, 2006.
[bib] [pdf] [abstract]
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.
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[75] | Ingo Kofler, Hermann Hellwagner, MPEG-21-based Cross-Resource Adaptation Decision-Taking, In Proceedings of the 2nd International Conference on Automated Production of Cross Media Content for Multi-channel Distribution (AXMEDIS) (Ng Kia, Atta Badii, Pierfrancesco Bellini, eds.), Firenze University Press, Firenze, Italy, pp. 207-214, 2006.
[bib] [pdf] [abstract]
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.
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[74] | Dietmar Jannach, Klaus Leopold, Christian Timmerer, Hermann Hellwagner, A Knowledge-Based Framework For Multimedia Adaptation, In Applied Intelligence - Special Issue: Innovations in Applied Artificial Intelligence, Springer, vol. Vol. 24, no. No. 2, Berlin, Heidelberg, New York, pp. 109-125, 2006.
[bib][url] [abstract]
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.
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