Abstract: Multimedia is gaining ever more importance on the Internet. This increases the need for intelligent and efficient video caches. Typical Web proxies were not designed to efficiently support the caching of videos. 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 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 and use the emerging MPEG-7 standard to describe the scalability options for a video. The proxy parses the MPEG-7 description and decides, based on this description and the terminal capabilities of the client, which adaptation step to choose. Simple MPEG-4 audio-visual streams are supported by filter operations in the compressed domain that realize several temporal scaling algorithms and color reduction. In this paper, we will 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.

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: Multimedia streaming becomes ever more popular. The multimedia standard MPEG-4 has been designed to support scenes of different levels of complexity and applications with low bandwidth requirements up to very high bandwidth requirements. One protocol suitable to transfer this kind of data over IP networks is the real-time transport protocol (RTP). This report describes standardized and proposed payload formats that support the transport of MPEG-4 elementary streams over RTP connections. These RTP packetization formats are compared w.r.t. their suitability for the adaptation (scaling) of the media data within the network, i.e., by advanced routers or proxy caches. This adaptation process is governed by metadata that need to be transferred and inspected in conjunction with the media streams.

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: The virtual interface (VI) architecture standard was developed to satisfy the need for a high throughput, low latency communication system required for cluster computing. VI architecture aims to close the performance gap between the bandwidths and latencies provided by the communication hardware and visible to the application, respectively, by minimizing the software overhead on the critical path of the communication. This paper presents the results of a performance study of one VI architecture hardware implementation, the Giganet cLAN (cluster LAN). The focus of the study is to assess and compare the performance of different VI architecture data transfer modes and specific features that are available to higher-level communication software like MPI in order to aid the implementor to decide which VI architecture options to employ for various communication scenarios. Examples of such options include the use of send/receive vs. RDMA data transfers, polling vs. blocking to check completion of communication operations, multiple VIs, completion queues and scatter capabilities of VI architecture.

Abstract: In this paper we present the design, architecture and implementation of the A2QM3 System. It provides programmers re-usable QoS-aware Control Objects to enable building a complete middleware for adaptive applications over active networks. We introduce the programming model, the system architecture, and show the parts that make this system a full-featured middleware supporting QoS-aware reliable stream-oriented communication, communication using the request/reply-based CORBA model and real-time streaming for continuous multimedia contents.

Abstract: Adaptation is becoming an increasingly important tool for resource and media management in distributed multimedia systems. Best-effort scheduling and worst-case reservation of resources are two extreme cases, none of them well suited to cope with large-scale, dynamic multimedia systems. The middle course can be met by a system which dynamically adapts its data, resource requirements, and processing components to achieve user satisfaction. Nevertheless, there is no agreement about the questions, where, when, what and who should adapt. A number of papers have been published in recent years, where adaptation is a central issue, however, in most different interpretations and generally in a somehow limited scope; e.g.,[1, 2, 8, 9, 10, 12]. A distributed multimedia system comprises several types of components, such as media servers, meta-databases, proxies, routers, clients. Also, a large number of adaptation possibilities exist, from simple frame dropping up to virtual server systems which dynamically allocate new resources on demand. The main question is, which kind of component can be best used for what kind of adaptation. In the ADMITS project (Adaptation in Distributed Multimedia IT Systems), we are seeking for answers to exactly this basic question, and to a number of related questions.

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: Elliptic curve cryptosystems allow the use of prime fields with special prime moduli that speed up the finite field arithmetic considerably. Two algorithms for reduction with respect to special moduli have been implemented in software on both a 32-bit and a 64-bit platform and compared to well-known generic modular reduction methods. Timing results for multiplications in prime fields of size between 2^191 and 2^512 are presented and discussed.

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: This paper presents an inexpensive cluster-based QoS networking testbed that can be employed to \emulate" different networks for multimedia communication ex-periments. Such a network can be built using standard PC and Ethernet hardware and open-source software components, e.g., IP routing and traÆc control avail- able in recent Linux kernels as well as a Differentiated Services package built atop these building blocks. The testbed can exibly be configured to model various link bandwidths as well as IP routers capable of classifying, queuing (with various disciplines), forward-ing and/or dropping packets and shaping traÆc. The QoS components and facilities of the testbed are in-troduced and initial performance analysis experiments and results are reported. A simple video streaming application under QoS control is presented to show the usefulness of the testbed.

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.