Abstract: Extracting and visualizing concepts and relationship between text documents strongly depends on the used similarity measure. In order to provide meaningful visualizations and to extract useful knowledge from document collections, user needs must be captured by the internal representation of documents, and the used similarity measure. In most applications the Vector Space Model and the Cosine similarity are used therefore and serve as good approximations. Nevertheless, influencing similarities between documents is rather hard, since parameter tuning relies heavily on expert knowledge of the underlying algorithms, and the influence of different weighting schemes and similarity measures is not known before. In this paper we present an approach on how to adapt the vector space representation of documents by giving visual feedback to the system. Our approach starts by clustering a corpus of text documents and visualizing the results using multi dimensional scaling techniques. Afterwards, a 2D landscape visualization is shown which can be manipulated by the user. Based on these manipulations the high dimensional representation of the documents is adapted to fit the users need more precisely. Our experiments show that iterating these steps results in an adapted representation of documents and similarities, generating layouts as intended by the user and furthermore increases clustering accuracy. While this paper only investigates the influence on clustering and visualization, the method itself may also be used for increasing classification and retrieval performance since it adapts to the users need of similarity.

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.

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.

Abstract: The increasing diversity of devices and the heterogeneity of networks pose nowadays a challenge in the delivery and consumption of multimedia content. In this context, the Part 7 of the MPEG-21 standard formally named Digital Item Adaptation (DIA) targets the adaptation of multimedia content based on usage environment, such as network characteristics, terminal capabilities and user characteristics. But, MPEG-21 DIA does not take into account MPEG-7 semantics description tools, which provide means for a conceptual (semantic) description that is close to the human understanding of multimedia content. Therefore, to fill this gap, we propose an interactive and user-centric framework called Semantic Adaptation Framework (SAF). The SAF provides facilities for the generation of all the required semantic metadata and enables an MPEG-21 adaptation engine to semantically adapt the multimedia content in order to provide the user with the best possible experience.

Abstract: MPEG-21 Digital Item Adaptation (DIA) has recently been finalized as part of the MPEG-21 Multimedia Framework. DIA specifies metadata for assisting the adaptation of Digital Items according to constraints on the storage, transmission and consumption, thereby enabling various types of quality of service management. This paper provides an overview of DIA, describes its use in multimedia applications, and reports on some of the ongoing activities in MPEG on extending DIA for use in rights governed environments.

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.

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.

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 the same requirement: they operate on plain text encoded metadata which may become a burden especially in constrained and streaming environments, e.g., when metadata needs to be processed together with multimedia content which is available in a highly efficient, binary representation format. In this paper we present techniques for transforming such kind of metadata which is encoded using the well known MPEG-7 Systems Binary Format for Metadata (BiM) without additional en-/decoding overheads, i.e., within the binary domain. As such it enables us to process both the multimedia data as well as the metadata within its compressed domain, e.g., for metadata-driven adaptation purposes within intermediary network nodes which are becoming increasingly popular in the multimedia community as well as in the XML community.

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.

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.

Abstract: Universal Multimedia Access (UMA) has become a driving concept behind a significant amount of research activities. One of MPEG’s (Moving Pictures Experts Group) responses to UMA is MPEG-21 Digital Item Adaptation (DIA). In this paper we present how tools as specified within DIA (i.e., normative XML-based description formats) are applied in streaming and constrained environments enabling piece-wise multimedia content adaptation including the adaptation decision- taking process and the actual resource adaptation in a coding format-independent way. Additionally, we demonstrate how the metadata overhead imposed by DIA tools can be reduced by means of appropriate metadata encoding tools.

Abstract: The DAHL project aimed at demonstrating some of the research achievements at ITEC by extending anexisting web application with content-based search mechanisms and an adaptive streaming environment for video data. The search is based on MPEG-7 descriptions of video data, and video retrieval uses an MPEG-4 conforming adaptive streaming server and player, which allows to adapt the video stream dynamically to client capabilities, user preferences, and available network bandwidth. This report describes the design, implementation, and integration work done in the DAHL project.

Abstract: We argue for the need of a tool that is able to provide QoS aware server applications with accurate information about current as well as predicted network characteristics. To address this issue, we present the design and evaluation of DANEF - a system that is able to estimate, process and forecast bottleneck bandwidth, available bandwidth, delay, jitter and loss of a certain path. Active measurements are performed by sending small ICMP packet trains and forecasts are performed by applying fast allgorithms that need only small initialization sets. The accuracy of the measurements is achieved by applying an efficient and innovative filtering mechanism, the correctness of the forecasts is achieved by dynamically selecting the best fitting forecast model and by considering the forecast error of previous samples. Our evaluation has shown that DANEF's measurement results are significantly more precise than those yield by the 5 most widely used tools called Bprobe, Cprobe, Pathload, Pathchar and Network Weather Service.

Abstract: We present the extension of an adaptive distributed multimedia streaming server architecture (ADMS) towards a Quality of Service based network infrastructure. The key component of the extension is the distributed active network estimation and forecasting tool (DANEF). It is able to estimate, process and forecast bottleneck bandwidth, available bandwidth, delay, jitter and loss of a certain path between the streaming server and the requesting client. Using this information, the server node that offers the best QoS for a certain client is selected from a set of possible candidates. Active measurements are performed by sending ICMP [15] packet trains and forecasts are performed by applying fast algorithms that need only small initialization sets. The accuracy of the measurements is achieved by applying an efficient and innovative filtering mechanism, the correctness of the forecasts is achieved by dynamically selecting the best fitting forecast model and by considering the forecast error of previous samples. We have compared DANEF to other already existing measurement tools like BProbe, Cprobe, Pathload, Pathchar and Network Weather Service. As can be found in the evaluation part of this paper DANEF is much better suited for estimating QoS characteristics in the context of multimedia streaming than the other 5 tools it has been compared to.

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.

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.

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.

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.

Abstract: In recent years there has been a big increase in the amount and usage of all different kinds of multimedia data. Ranging from digital video broadcasting over the Internet to sharing digital photos and videos from the last holidays with others, multimedia is around everywhere today. Multimedia metadata help us to manage and search for information in these data. They offer searching for keywords as well as semantic search for textual descriptions of complex activities in audio, video and image. Based upon the research and implementation of the DAHL project, we present an approach for the annotation and presentation of content-variations of videos. First we want to have a look at muvino, a tool for creating MPEG-7 metadata descriptions of videos. After that the presentation of search results, especially the variations of videos or video segments is highlighted

Abstract: Video adaptation is an active research area aiming at delivering heterogeneous content to yet heterogeneous devices under different network conditions. It is an important component of multimedia data management to address the problem of delivering multimedia data in distributed heterogeneous environments. This paper presents a novel method of video adaptation called segment-based adaptation. It aims at applying different reduction methods on different segments based on physical content. The video is first partitioned into homogeneous segments based on physical characteristics. Then optimal reduction methods are selected and applied on each segment with the objective of minimizing quality loss and/or maximizing data size reduction during adaptation. In addition to this new method of variation creation, the commonly used reduction methods are also implemented. To realize variation creation, a unifying framework called the Variation Factory is developed. It is extended to the Multi-Step Variation Factory, which allows intermediary videos to serve as variations and also as sources to further variations. Our proposals are implemented as part of a server component, called the Variation Processing Unit (VaPU) that generates different versions of the source and an MPEG-7 metadata document.

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.

Abstract: Unser Tutorial gibt einen Überblick über die neuesten MPEG-Standards MPEG-7/21/A/B und streicht ihre Bedeutung für Multimedia-Datenbanken heraus.