Abstract: This paper introduces a new approach of approximating the selectivity of multimedia range queries. Estimating the selectivity of a range query is a pre-requisite to optimize a multimedia database query. We use the DBSCAN clustering technique for finding high density areas in the data set. Then, the selectivity is approximated with the help of a density function in combination with the volume of the query’s hypersphere. Our approach is fast and accurate which was evaluated on an image data set using the MPEG-7 Scalable Color Descriptor. The technique is integrated with the help of the extensible optimizer architecture in the Oracle multimedia database system.

Abstract: During its lifetime, multimedia content undergoes different stages or cycles fromproduction to consumption. Content is created, processed or modified in a postproduction stage, delivered to users, and finally, consumed. Metadata, or descriptive data about the multimedia content, pass through similar stages but with different time lines.1 Metadata may be produced, modified, and consumed by all actors involved in the content production-consumption chain. At each step of the chain, different kinds of metadata may be produced by highly different methods and of substantially different semantic value.

Abstract: Im MPEG-21 Multimedia Framework Standard spielt das Digital Item als fundamentale Transaktions- und Austauscheinheit eine zentrale Rolle. Dieser Artikel beschreibt eine Methodik und Software zur Erstellung und den Konsum von Digital Items. Das Softwarewerkzeug setzt sich aus zwei Teilen zusammen: Der DI Builder erlaubt es Benutzern MPEG-21 Digital Items zu erstellen, die mit dem DI Consumer konsumiert werden können. Der Konsum eines Digital Items umfasst das Abspielen von Mediendateien und die Betrachtung der Metadaten eines Digital Items. Die Software demonstriert Teile des MPEG-21 Standards, im speziellen Teil 2-Digital Item Declaration, Teil 3-Digital Item Identifcation, Teil 5-Rights Expression Language, Teil 6-Rights Data Dictionary und Teil 7-Digital Item Adaptation.

Abstract: The ISO/IEC Motion Picture Group (MPEG) issued in 2002 a standard, called MPEG-7, which enables the content description of multimedia data in XML. The standard supports applications to exchange, identify and filter multimedia contents based on MPEG-7 descriptions. However, processing MPEG-7 documents on mobile terminals is problematic, since the verbose XML is not adequate to limited bandwidth, low computational power and limited battery life. In this document we describe an index system that allows filtering and random access to encoded MPEG-7 streams and which overcomes the limitation of the network and the consuming terminal. Encoding is applied in order to reduce the data rate of the XML documents to be transmitted. The indexed parts of the encoded streams can be accessed without the need to deserialize the complete stream. Furthermore, the system is evaluated and results of the experimental evaluation are discussed.

Abstract: This paper presents the experiences of creating the information system MEDPHYT which is built to collect data on the complete European pharmaceutical and toxicological plant world whose representatives are determined by medical and therapeutic benefit. Focus of the database content is the plant with description of their botanical characteristics, and history of discovery of therapeutic use, etymology, and synonyms. Apart the botanical characterisation there is information on both medical relevant biochemical compounds and their physicochemical characteristics, and toxicological as well as pharmaceutical facts. These data sets determine the basic system of MEDPHYT.

Abstract: We present a possibility how to add proactive behaviour to Video-on-Demand systems. To do so we propose categorizing videos and using external information as well as observing the behaviour of our clients. We examined 23 predictor functions on artificial and real datasets using different similarity measures to compare them. Our model is quite simple; therefore some extensions are proposed at the end.

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 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.

Abstract: The precision of the predictors used in the ADMS[1] can be determined by similarity. There are already such measures[2] given, but we do not know exactly what efficiency they have and how well they show the difference between two lists. Kendall’s tau • Spearman’s footrule • Ulam’s distance We examined the characteristics of these similarity measures and developed some more measures that fit better our needs. One of the main goals is to consider the similarity more important at the begin of list, than at the end of list. Because the clients at the begin of the list probably will request more videos. During our work we defined 20 special ordered lists with 17 elements each. We tested the different measures on these lists. We also tested the Kemeny distance, which was defined in paper[3]. We modified the Spearman’s footrule and the Ulam’s distance according to the goal defined above (the top of the list considerate with higher weight (Weighted Spearman’s footrule, Weighted Ulam’s distance). Using the already known measures we developed a more complex, mixed measure, which uses more factors when defining the similarity. Finally we compared the 7 different measures using the artificially defined lists. With using the similarity measures we can tell how good the predictors[2] work in ADMS project. We could order the predictors by goodness, testing them on a real database (the World Cup ’98 Website’s access log).

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.

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.

Abstract: Proxy-cache deployment in the LANs has become a current practice aimed at increasing the availability of the data while also reducing client perceived latency, reduce the load on origin servers as well as the external network bandwidth consumption. As the load increases, due to an increase in client’s requests for both cached and non-cached data, it often happens that one single proxy-cache can not handle all the incoming requests. For those situations, when request dropping and cache replacement becomes necessary, we propose an alternative, namely proxy-cache splitting. Our solution is to dynamically deploy additional proxy-caches inside the LAN, and divert towards them some of the requests addressed to the original proxy-cache(s). By doing this we can achieve even better response time, load balancing, higher availability and robustness of the service than in the case in which a single proxy-cache is used.

Abstract: The importance of the historical and human aspects of the didactics of informatics is discussed. The threefold human aspects of teaching: by, for and about people is explored. Using the example of the notion of the procedure, the potential of the historical discussion is investigated. A strengthening of the historical and human view is required both in university research and in the curricula of the informatics education at both secondary and university levels.

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.

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.

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 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: 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.

Abstract: Video adaptation is an active research area aiming at delivering heterogeneous content to yet heterogeneous devices under different network conditions. This paper presents an architecture for generating variations (different versions) from methods such as video transcoding, media conversion and summarization. The work in this paper concentrates on video data and aims to show video variation supported with metadata as an approach to adaptation to enable ubiquitous access. By video products are defined and the variation factory is introduced It generates different versions of the source and an MPEG-7 metadata document. The information contained in the metadata document helps the system to identify the most appropriate version that meets the required quality of service (QoS). In addition to the implementation of the commonly used reduction methods, two novel methods, viz. object-based and segment-based variations are introduced. Our proposals are implemented and experimentally validated.

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.

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.

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).

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.