Fu, Zhengjia. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 64-70 ). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Design for group network communication --- p.6 / Chapter 2.1 --- Performance metrics of network Voice Conference: GMOS --- p.7 / Chapter 2.2 --- Conference Leader Selection strategies --- p.11 / Chapter 2.3 --- Experiment Description --- p.14 / Chapter 2.4 --- Data analysis and results --- p.16 / Chapter 2.5 --- Applications of Proposals to Voice Conference --- p.25 / Chapter 3 --- P2P Application Identification --- p.27 / Chapter 3.1 --- Periodic Group Communication Patterns --- p.28 / Chapter 3.1.1 --- Terminology for Behavioral Patterns --- p.29 / Chapter 3.1.2 --- Pattern 1: Gossip of Buffer Maps --- p.30 / Chapter 3.1.3 --- Pattern 2: Content flow control --- p.31 / Chapter 3.1.4 --- Pattern 3: Synchronized Link Activation and Deactivation --- p.32 / Chapter 3.2 --- Identification Based on behavioral signatures --- p.33 / Chapter 3.2.1 --- Algorithm Overview --- p.34 / Chapter 3.2.2 --- Sequence Generation (SG1): Time Series for the Gossip Pattern --- p.36 / Chapter 3.2.3 --- Transform Time-domain Sequence to Frequency-domain Sequence --- p.36 / Chapter 3.2.4 --- Sequence Generation (SG2): Time Series for Content Flow Control Pattern --- p.40 / Chapter 3.2.5 --- Sequence Generation (SG3): Time Series for Synchronized Start and Finish of Flows --- p.41 / Chapter 3.2.6 --- Analyzer step --- p.47 / Chapter 3.3 --- Behavioral signatures of popular P2P applications --- p.47 / Chapter 3.4 --- Experiment Results --- p.49 / Chapter 3.5 --- Discussion --- p.52 / Chapter 4 --- Related Work --- p.58 / Chapter 5 --- Conclusion --- p.62 / Bibliography --- p.64

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A key feature of recent agricultural extension programs has been the focus on increased participation for local, rural communities in the overall decision-making process. This move towards increasing community participation has raised expectations in terms of communication: communication between central research facilities and rural communities, between rural communities and central research facilities, and amongst the rural communities themselves. In order to provide effective communication along each of these channels, attention is turning to the extension trainers deployed in the field. For extension trainers this emerging communication role is distinct from, and supplementary to, the conventional technical training function. The thesis highlights the lack of effective training in communication skills in existing extension training programs. It identifies the flip chart as the most widely used visual aid for farmer training, and the overhead projector as the most widely used visual aid for in-service training. The thesis develops a comprehensive set of training competencies and content for teaching those two technologies, derived from individual task analyses and an extensive literature review. A range of strategic alternatives for the delivery of those competencies in a developing country are then formulated and examined. Central to the different strategies considered is the use of interactive multimedia as a key delivery technology. Two proprietary CDROMs have been designed and produced specifically to the support training in the design and production skills for overhead projector and flip chart technologies. The design, content and production of the CDROMs is described, and both technical and user evaluations are presented. The two CDROMs have been field-tested in Sri Lanka, across a broad range of strategic alternatives. The outcome is a set of guidelines and specific structures for training programs in overhead projector and flip chart technologies. The guidelines are generic and broadly applicable. The case studies also indicate a particular subset of preferred strategies for the future deployment of interactive multimedia-based training in developing countries. Most specifically, the thesis indicates a balance between and the need for mix of interactive multimedia modules along with face-to-face training support / Doctor of Philosophy (PhD)

The research reported here focuses on the application of multimedia to the teaching of information skills in academic libraries. Specifically, the research project has involved the development and evaluation of a multimedia system to instruct novice users of online library catalogues. The research has included an investigation of the characteristics and needs of novice library users. The ways in which novices approach using library-based information technologies which may be applied to any instructional programme for teaching novices how to use library-based information technologies. The research project has involved the development of a comprehensive multimedia system based on the theoretical model. The multimedia system was designed using Macromedia Director v.4.04. The production techniques and operation of the multimedia system are described in some detail. The multimedia system was evaluated and tested using formative evaluation strategies. The evaluation involved the prototype system being reviewed by expert librarians, and multimedia producers, as well as novice users of online library catalogues. The information gathered during the evaluation was used to make suggestions about improvements to the design of the prototype. The results of the evaluation are reported and analysed. / Master of Arts (Hons)

This dissertation was motivated by the exponential growth in bandwidth capacity of the Internet, coupled with the immense growth of broadband adoption by the public. This has led to the development of a wide variety of new online services. Chief amongst the emerging applications is the delivery of multimedia contents to the end users via the network on-demand. It is the “on-demand” aspect that has led to problems which, despite the advances in hardware technology and network capacity, have hampered wide scale adoption of multimedia delivery. The focus of this dissertation was to address these problems, namely: scalability, cost-effectiveness, and network quality of service for timely presentation of multimedia contents. We proposed an architecture, which we referred to as “Delayed-Multicast”, to address the scalability problem. The new architecture introduced buffers within the network to reduce demands on core network bandwidth and server load. A feasibility study of the architecture was conducted through the use of a prototype. It was found that such a system is within reach by demonstrating the prototype using cheap, common-of-the-shelf (COTS) components, and with help of freely available system software such Linux with real-time support. The introduction of buffers within the network led to the requirement of how to minimize buffer space. We developed an optimal algorithm for allocating buffer space in a single level caching layout (i.e. only one buffer in the transmission path from the server to the end user). For the case of multi-levels network caching, we thoroughly examined different optimization problems from an algorithmic perspective. These problems included how to minimize total system memory, and minimize the maximum memory used per node. We proved that determining the optimal buffer allocation in many of these iv v cases is an NP-complete problem. Consequently, we developed heuristics to handle multi-level caching and showed through simulations that the heuristics greatly help in minimizing buffer space and network bandwidth requirement. An important aspect of the heuristics was how to handle the case when the arrival times of client requests were not known a priori. For these “online” problems we also proposed heuristics that can significantly reduce overall system resource requirements. If the cost of buffer space was also taken into account along with the cost of network bandwidth, a different optimization problem was how to minimize the total system cost. Here, we also proposed heuristics, which in simulations show that the total system cost can be significantly reduced. Besides the problems associated with resource allocation, in terms of buffer space and bandwidth, we also examined the problem of how to provision the necessary network quality of service on-demand. Most current networks rely on best-effort delivery which is ill suited for the delivery of multimedia traffic. We proposed a solution which relied on the use of a programmable network plane, that is present in many current routers, to dynamically alter the priority of flows within the network in real-time. We also demonstrated the effectiveness of the flow prioritization on an actual Nortel router. Finally, we examined the problem of how to admit and achieve fair bandwidth allocation for the end-users within a Differentiated Service (DiffServ) network. Diff- Serv is an IETF standard that aims to provide a “better than best-effort” network in a scalable manner, and is used widely, especially within the same autonomous domain for prioritization different classes of traffic. However, there are open problems on how to provide fair bandwidth allocation amongst competing flows. We proposed an edge-aware resource discovery loop, which as the name suggests, sent packets to gather information about the internal states of the core network. With this information, we proposed a price-based admission control algorithm for use within the DiffServ network that would allow fair admission, effective congestion control, and fair bandwidth allocation amongst different traffic flows.

The thesis describes the development during the 1990s of visual artists' utilisation of computer-based interactive multimedia and the production internationally, with a focus on Australian artists, of artworks on the CD-ROM media format. Earlier parts of the author's research led to the exhibition, 'Burning the Interface &lt International Artists' CD-ROM&gt', which he co-curated, opening at the Museum of Contemporary Art, Sydney, in 1996, before touring to Perth, Brisbane, Melbourne and Adelaide. The thesis surveys the range of practice by artists working with digital media and the opportunities for exhibition in the public spaces of museums, galleries and the street, and advances scenarios for correcting the laxity of response by the exhibiting institutions to the vigour with which Australian artists represented their work and ideas at this time in national and international forums. Four published artists' work on CDROM are analysed in detail, and a concluding chapter about 'interactive multimedia' and its usefulness as an art medium to the artist introduces the studio practice component of this MFA submission. This takes the form of a prototype 'experimental' version of an interactive multimedia work on CD-ROM, ('Strangers on the Land') a copy of which is contained in a pocket at the rear of the bound version.

This thesis presents a research work based on an integrated multi-modal approach for sports video indexing and retrieval. By combining specific features extractable from multiple (audio-visual) modalities, generic structure and specific events can be detected and classified. During browsing and retrieval, users will benefit from the integration of high-level semantic and some descriptive mid-level features such as whistle and close-up view of player(s). The main objective is to contribute to the three major components of sports video indexing systems. The first component is a set of powerful techniques to extract audio-visual features and semantic contents automatically. The main purposes are to reduce manual annotations and to summarize the lengthy contents into a compact, meaningful and more enjoyable presentation. The second component is an expressive and flexible indexing technique that supports gradual index construction. Indexing scheme is essential to determine the methods by which users can access a video database. The third and last component is a query language that can generate dynamic video summaries for smart browsing and support user-oriented retrievals.

L'unité du travail réside en ce qu'on s'intéresse à la recherche de structure dans les données numériques (issues de données multimédia), en vue d'y faciliter la recherche d'information. Le cadre méthodologique de la résolution est que nous privilégions ici celui des modèles probabi- listes, en particulier les mélanges de lois, et de l'estimation statistique associée. La recherche de structure implique que le jeu de données étudié est composé de sous-populations de caracté- ristiques distinctes : il s'agit de séparer et de caractériser ces sous-populations, deux problèmes fortement imbriqués. Les entités extraites et les attributs qu'on en leur associe seront alors directement utiles pour la recherche d'information.

Ce document présente une synthèse des activités autour d'un thème central : informatique répartie. Dans la première partie sont présentés les travaux dans le domaine de l'évaluation de performances et les mesures de systèmes répartis. Dans un premier temps, nous étudions des primitives de synchronisation de type fork-join. Par la suite, nous analysons les performances des programmes parallèles et nous comparons des stratégies de duplication d'objets. Enfin, nous présentons une méthode d'estimation du temps global pour la mesure de performances des systèmes répartis. La deuxième partie concerne la conception et la réalisation de systèmes répartis. Nous commençons par spécifier les primitives de communication du projet Epsilon et nous poursuivons en présentant le travail effectué dans le cadre du projet Guide : la gestion de l'exécution répartie, les mécanismes d'invocation d'objets à distance, les protocoles de communication, la gestion des groupes d'objets et l'administration de sites. La troisième partie est consacrée aux aspects inhérents aux autoroutes de l'information du futur : la recherche de l'information sur grands réseaux et la représentation des données multimedia. En conclusion, nous présentons un projet de recherche s'inscrivant dans le domaine du multimedia réparti qui concerne le développement de l'infrastructure de l'information pour les réseaux futurs. Ce projet a pour objectif la conception et le développement des services communs et des outils pour faciliter la mise en oeuvre des applications multimedia distribuées.