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: A multi-clip query requests multiple video clips. In this paper we address the multi-clip query optimization problem. We propose a new heuristics called Restricted Search Interval that maximizes clip sharing between queries and consequently reduces the workload of the video server. An adaptation of our heuristics for optimizing the response time of the query is presented as well. The experimental results show that the suggested heuristics reduces the server workload by about 68% in comparison to a classical heuristic approach.

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: Multimedia services typically need not only huge resources but also a fairly stable level of Quality of Services. This requires server architectures that enable continuous adaptation. The Adaptive Distributed Multimedia Server (ADMS) of the University Klagenfurt is able to dynamically add and remove nodes to the actual configuration, thus realizing the offensive adaptation approach. This paper focuses on the optimal placement of nodes for hosting certain ADMS components (the so-called data collectors, collecting and streaming stripe units of a video) in the network. We propose four different algorithms for host recommendation and compare the results gained by running their implementations on different test networks. The greedy algorithm seems to be a clear looser. Among the three other algorithms (particle swarm, linear programming and incremental) there is no single winner of the comparison, they can be applied in a smart combination.

Abstract: We present an adaptive distributed multimedia server architecture (ADMS) that builds upon the idea of offensive adaptivity, where the server proactively controls its layout through replication or migration of server components to recommended hosts. Proactive actions are taken when network or server resources become critical when fulfilling client demands. Recommendations are provided by a so-called “host recommender” which represents an integral part of Vagabond2 - the middleware used for component distribution. Recommendations are based on measured or estimated server and network resource availabilities. Network distance and host resource metrics - obtained from network and host resource services respectively - may be communicated as MPEG-21 DIA descriptors. Finally we evaluate our architecture in a real-world streaming scenario.

Abstract: Web caching is an important technique to scale the Internet. One important performance factor of Web caches is the replacement strategy. Due to specific characteristics of the World Wide Web, there exist a huge number of proposals for cache replacement. This article proposes a classification for these proposals that subsumes prior classifications. Using this classification, different proposals and their advantages and disadvantages are described. Furthermore, the article discusses the importance of cache replacement strategies in modern proxy caches and outlines potential future research topics.

Abstract: Die Moving Picture Experts Group, eine Arbeitsgruppe der ISO SC29, ist seit 1988 aktiv und hat mit ihren MPEG-1/2/4 einen entscheidenden Einfluss auf die Multimedia-Industrie genommen.Mit der Verabschiedung MPEG-7 wurde von der Moving Picture Experts Group (MPEG) im März 2002 als Internationaler Standard verabschiedet. Nach der erfolgreichen Einführung der Standards MPEG-1/2/4 zur audiovisuellen Kodierung von Inhalten ist MPEG-7 ein Standard, der ein Austauschformat für Beschreibungen von multimedialen Inhalten festlegt.

Abstract: Broadly used Database Management Systems (DBMS) are not able to tackle the requirements of multimedia in querying, indexing and content modeling. Therefore, extenders for multimedia data types have been proposed. These extensions, however, offer only limited semantic modeling and rely on basic index structures which do not meet the whole nature of multimedia, for instance for a Nearest-Neighbor Search. In this context, the paper presents a methodology for enhancing extensible ORDBMS for multimedia data. In particular, we introduce an MPEG-7 Multimedia Data Cartridge which includes a semantically rich metadata model for multimedia content relying on the MPEG-7 standard. Furthermore, to fulfill the needs for efficient multimedia query processing, we created in this Cartridge a new indexing and query framework for various types of retrieval operations

Abstract: Bei der Indizierung von Videoarchiven haben im allgemeinen bessere Ergebnisse einen höheren Preis. Automatische Indizierung, basierend auf physikalischen Eigenschaften, kann für viele Bereiche (wie z.B. ein Grossteil der Unterhaltung) ausreichend gute Ergebnisse erzielen. Sie ist allerdings in der Genauigkeit der Fragestellungen eingeschränkt, und zwingt uns – oft unbewusste – Suchkriterien auf. Wenn es uns wichtig ist, auf fein differenzierte Fragen genaue Antworten zu erhalten (wie das z.B. in wissenschaftlich/technischen Systemen meistens der Fall ist), so sind wir auf eine zumindest teilweise manuelle Annotierung angewiesen. In einem kombinierten System – wie dem VIDEX-Modell – können die physikalischen Eigenschaften dazu benutzt werden, den manuellen Annotierungsprozess zu erleichtern. Kombinierte Systeme dieser Art bieten beide Arten der Indizierung an und kombinieren sie miteinander. Längerfristig ist zu erwarten, dass sich zu jeder Anwendung die angemessenen Indizierungs- und Suchmethoden herausstellen. Die zwei Verfahren – das automatische und das teils manuelle – sollten nicht als Gegner, sondern als Partner angesehen werden.

Abstract: This paper introduces a mobile agent-based infrastructure for an adaptive multimedia server enabling a dynamic migration or replication of certain multimedia applications among a set of available server nodes. It discusses the requirements from both, the server’s and the middleware’s point of view to each other and comes up with a specification and implementation of a CORBA-based interface between them.

Abstract: Due to the future dominance of video data video caching will be an important performance factor in future networked multimedia systems. A major component of video caches is the replacement strategy. This paper presents replacement strategies for video caches that incorporate quality reduction and the use of metadata given by the content provider. The strategies are evaluated by simulation.

Abstract: This work introduces a framework for adapting MPEG-4 intra- and inter-Elementary Streams and for encoding the results in an MPEG-7 stream to be used for resource adaptation on the delivery path to the user.

Abstract: Multimedia Database Systems (MMDBMS) organize and store multimedia data for content retrieval. The relying multimedia data models represent abstractions of media objects for querying, indexing, and so on. However, most currently available implementations reval shortcomings. Either they are limited by one kind of multimedia data supported or by the capacity of their semantic modelling. Despite the upcoming MPEG-7 standard for representing low-level and high-level features of multimedia and respective annotation and use tools (see http://www.mpeg-industry.com), we are not aware of any MMDBMS product which integrates this standard for the purpose of a more meaningful indexing and querying. In this context, our paper presents a Multimedia Data Cartridge (MDC) for demonstration at ACM Multimedia 2002 that implements an object-relational data model for the core part of the MPEG-7 standard. It is an open and extensible system realized with the Oracle Data Cartridge technology. Oracle offers with that technology a mechanism for extending the capabilities of an Oracle database (e.g., type system, query processing and indexing) for the users needs. Besides the more effective modelling of multimedia content, efficient retrieval was considered. Efficient query processing is guaranteed through new database indexing mechanisms. Innately, most database systems provide only a limited number of integrated access methods such as B-trees. Available multimedia database extension packages (e.g., DataBlades of Informix) rarely handle indexing of d-dimensional data (e.g., feature vectors with d>2) or advanced similarity search functionalities (e.g., k-NN search). These circumstances limit the use of database systems in multimedia. For overcoming this drawback, we introduce an Multimedia Indexing Framework (MIF) relying on the GiST framework. Finally, in order to use the MMDBMS we provide query and presentation interfaces which automatically adapt to their usage environment.

Abstract: The Multimedia Description Standard MPEG-7 is an International Standard since February 2002. It defines a huge set of description classes for multimedia content, for its creation and its communication. This article investigates what MPEG-7 means to Multimedia Database Systems (MMDBSs) and vice versa. We argue that MPEG-7 has to be considered complementary to, rather than competing with, data models employed in MMDBSs. Finally we show by an example scenario how these technologies can reasonably complement one another..

Abstract: This book constitutes the refereed proceedings of the 13th International Conference on Database and Export Systems Applications, DEXA 2002, held in Aix-en-Provence, France, in September 2002. The 89 revised full papers presented together with three invited papers and a position paper were carefully reviewed and selected from 241 submissions. The papers are organized in topical sections on Web, workflow, data warehouses and datamining, applications, XML, distributed systems, knowledge engineering, advanced databases, queries, information retrieval, and indexing.

Abstract: Multimedia databases; Processing of a multimedia join; Nearest neighbor search.

Abstract: This paper introduces a mobile agent-based infrastructure for an adaptive multimedia server enabling a dynamic migration or replication of certain multimedia applications among a set of available server nodes. It discusses the requirements from both, the server’s and the middleware’s point of view to each other and comes up with a specification and implementation of a CORBA-based interface between them.

Abstract: This book constitutes the refereed proceedings of the Second International Workshop on Multimedia Databases and Image Communication, MDIC 2001, held in Amalfi, Italy, in September 2001. The 16 revised full papers presented together with two invited papers were carefully reviewed and selected for inclusion in the book. The papers are organised in topical sections on image and visual computing applications, multimedia technology, image and visual information querying and browsing, and video indexing and communication.

Abstract: The workshop investigated, to what extent can component technology help to enhance the quality of distributed multimedia systems. Especially, to what extent can we achieve better reuse of multimedia content, reuse of code, interoperability, portability and performance. All authors agreed upon the necessity of building distributed multimedia systems of components as opposed to monolithic systems. The granularity of the components is an open issue, it can be stated, however, that most contributors presented solutions with rather heavy-weight components. Some of the presentations required explicitly standardization of multimedia formats, both for content and meta data. Most presenters touched the topic of multimedia-aware standardized middleware. Available middleware standards still do not support to a sufficient extent techniques to provide a guaranteed quality of service, and fit thus not well to be used for distributed multimedia. Multimedia system providers are often not interested to publish their interfaces. Thus, even if the internal design is component-oriented, the rest of the world has not much gain from this. Academic research can push openness and have a positive influence on industry. KEYWORDS Distributed Multimedia Systems, Quality of Service, Middleware, Component based Distributed Multimedia Systems, Adaptivity.