Network-Integrated Multimedia Middleware, Services, and Applications

Today, there is a strong trend towards networked multimedia devices. However, common multimedia software architectures are restricted to perform all processing on a single system. Available software infrastructures for distributed computing — commonly referred to as middleware — only partly provide the facilities needed for supporting multimedia in distributed and dynamic environments. Approaches from the research community only focus on specific aspects and do not achieve the coverage needed for a full-featured multimedia middleware solution. The Network-Integrated Multimedia Middleware (NMM) presented in this thesis considers the network as an integral part. Despite the inherent heterogeneity of present networking and device technologies, the architecture allows to extend control and cooperation to the network and enables the development of distributed multimedia applications that transparently use local and remote components in combination. The base architecture of this middleware is augmented by several middleware services that especially aim at providing additional support for developing complex applications that involve mobile users and devices. To this end, previously not available services and corresponding abstractions are proposed, realized, and evaluated. The performance and applicability of the developed middleware and its additional services are demonstrated by describing different realized application scenarios.Eine wachsende Anzahl von Multimedia-Geraeten verfuegt heute bereits ueber Netzwerkschnittstellen. Verfueugbare Multimedia Software-Architekturen beschraeanken jedoch die gesamte Datenverarbeitung auf ein einzelnes System. Verbreitete Software-Infrastrukturen fuer Verteilte Systeme — ueblicherweise Middleware genannt — bieten nur teilweise die Eigenschaften, die fuer die Multimedia-Datenverarbeitung in vernetzten und dynamischen Umgebungen benoetigt werden. Ansaetze aus der Forschung behandeln nur spezielle Teilaspekte und erreichen deshalb nicht den Funktionsumfang einer vollwertigen Middleware fuer Multimedia. Die in dieser Arbeit beschriebene Netzwerk-Integrierte Multimedia Middleware (NMM) betrachtet das Netzwerk als integralen Bestandteil. Die Architektur erlaubt trotz der inhaerenten Heterogenitaet der vorhandenen Netzwerk- und Geraetetechnologie die Kontrolle und das Zusammenspiel von Systemen auf das Netzwerk auszuweiten. Dies ermoeglicht die Entwicklung verteilter Multimedia-Anwendungen, die transparent lokale und entfernte Komponenten zusammen einsetzen. Die Kernarchitektur dieser Middleware wird durch verschiedene Dienste erweitert, die speziell die Realisierung komplexer Anwendungsszenarien mitmobilen Geraeten und Benutzern unterstuetzt. Insbesondere werden neue, bisher nicht vorhandene Middleware-Dienste und zugehoerige Abstraktionen vorgeschlagen, realisiert und evaluiert. Anhand verschiedener Anwendungsszenarien wird die Leistungfaehigkeit, die Effizienz und die praktische Relevanz der entwickelten Middleware und der ergaenzenden Dienste demonstriert

Specializing Visualization Algorithms

In this paper we look at the potential of program specialization techniques in the context of visualization. In particular we look at partial evaluation and pass separation and how these have been used to automatically produce more e#cient implementations and how they can be used to design new algorithms. We conclude by discussing what we think are the applications were program specialization is most promising in visualization

Towards a Mathematical Concept of a Component and Its Use

We deal with the concept of a component considered as a black box that is a physical encapsulation of related services according to a published specification. These services can only be accessed through a consistent and published interface that includes an interaction standard. Such a notion of a component needs a carefully chosen semantic concept of a syntactic and a semantic interface that allows us to provide a precise unambiguous published specification. We present a mathematical model for the interface of components. We demonstrate its use for the modeling of software architectures, interoperability between components, and the process of incremental development. 1. Introduction A descriptive functional semantic model of distributed systems of interacting components is of major interest in many research areas as well as applications of computing science and systems engineering. For the modular, systematic development of systems and a proper method for for the design of s..

Gender-Biased Adaptations in Educational Adaptive Hypermedia

Studies show that there is a statistically significant gender difference regarding computer usage. For instance, a majority of female users expect less success from an interaction with a computer and are more likely to blame themselves in case something goes wrong. As a result, women considerably less often use a computer as a tool than men do. Now, if women do not use a computer as much as men do, they will not profit as much from the advantages of computational systems as they potentially could. That's why this paper reviews work about the causes of this problem, investigates an extended model, and develops possible preventions and reactions to it. Appropriate adaptivity cannot, however, be based on mere gender information which represents a bias only and may imply cliches and discrimination

Integrating Formal Description Techniques

. Using graphical description techniques for formal system development has become a common approach in many tools. Often multiple description techniques are used to represent different views of the same system, only together forming a complete specification. Here, the question of the integration of those description techniques and views becomes a major issue, raising questions of consistency and completeness. In this paper, we present an approach to ensuring conceptual and semantic consistency, influenced by experience gained from a first implementation of the AUTOFOCUS tool prototype. Finally, we show how this approach forms the basis for the definition of specification modules. 1 Introduction Using multiple description techniques has become a common approach for the toolbased system development. Prominent examples are SDL-based tools (e.g., ObjectGeode [19], SDT [18]) and automata-based approaches (e.g., ObjecTime [17]). Here, the specification of a system is spread out ove..