Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 89-94). Also available in electronic version.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

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In this paper, we present the design and evaluation of CQ-Buddy, a peer-to-peer (p2p) continuous query (CQ) processing system that is distributed, and highly-scalable. CQ-Buddy exploits the differences in capabilities (processing and memory) of peers and load-balances the tasks across powerful and weak peers. Our main contributions are as follows: First, CQ-Buddy introduces the notion of pervasive continuous queries to tackle the frequent disconnected problems common in a peer-to-peer environment. Second, CQ-Buddy allows for inter-sharing and intra-sharing in the processing of continuous queries amongst peers. Third, CQ-Buddy peers perform query-centric load balancing for overloaded data source providers by acting as proxies. We have conducted extensive studies to evaluate CQ-Buddy’s performance. Our results show that CQ-Buddy is highly scalable, and is able to process continuous queries in an effective and efficient manner. / Singapore-MIT Alliance (SMA)

Most existing Peer-to-Peer (P2P) systems support only title-based searches and are limited in functionality when compared to today’s search engines. In this paper, we present the design of a distributed P2P information sharing system that supports semantic-based content searches of relevant documents. First, we propose a general and extensible framework for searching similar documents in P2P network. The framework is based on the novel concept of Hierarchical Summary Structure. Second, based on the framework, we develop our efficient document searching system, by effectively summarizing and maintaining all documents within the network with different granularity. Finally, an experimental study is conducted on a real P2P prototype, and a large-scale network is further simulated. The results show the effectiveness, efficiency and scalability of the proposed system. / Singapore-MIT Alliance (SMA)

In this paper, we present a P2P-based database sharing system that provides information sharing capabilities through keyword-based search techniques. Our system requires neither a global schema nor schema mappings between different databases, and our keyword-based search algorithms are robust in the presence of frequent changes in the content and membership of peers. To facilitate data integration, we introduce keyword join operator to combine partial answers containing different keywords into complete answers. We also present an efficient algorithm that optimize the keyword join operations for partial answer integration. Our experimental study on both real and synthetic datasets demonstrates the effectiveness of our algorithms, and the efficiency of the proposed query processing strategies. / Singapore-MIT Alliance (SMA)

Peer-to-peer technologies have shown a lot of promise in sharing the remote resources effectively. The resources shared by peers are information, bandwidth, storage space or the computing power. When used properly, they can prove to be very advantageous as they scale well, are dynamic, autonomous, fully distributed and can exploit the heterogeneity of peers effectively. They provide an efficient infrastructure for an application seeking to distribute numerical computation. In this thesis, we investigate the feasibility of using a peer-to-peer infrastructure to distribute the computational load of Matlab and similar applications to achieve performance benefits and scalability. We also develop a proof of concept application to distribute the computation of a Matlab style application.

P2P is increasingly gaining its popularity for streaming multimedia contents. The architecture of streaming has shifted from traditional client server architecture to P2P architecture. Although it is scalable and robust it faces its own challenges and problems such as churn. In tree topology frequent joining and leaving of users in search for better quality and reliable streaming makes the P2P network instable. This thesis provides an effective approach to achieve a resilient network for streaming. Relying on a single tree to receive data from single parent may leave the user deprived of getting the data if any of its ancestors leaves the network. Therefore we present an ideal solution to this problem by introducing a backup tree for the existing base tree. The backup tree is constructed based on parameter such as bandwidth and delay. In case of failure of a node, its children along the tree receive the data from the nodes of backup tree. We present an efficient algorithm for the construction of base tree as well as the backup tree which are based on normalization of two entities of nodes: bandwidth and delay. Through mathematical formulation and experimental setups we show that introducing a backup tree for an existing base tree can help provide resilience to the network. / UOIT

Demands for multimedia content, one form of digital content, are continuously increasing at a phenomenal pace, as video features are commonly available on personal devices, such as iPod, cell phone, laptop, PDA, and Blackberry. The streaming service poses unique bandwidth and delay challenges to application designers. The size of a typical video content is usually orders of magnitude larger than that of any other type of content, resulting in high demands for bandwidth contribution from the content providers. Even more challenging, the content must be delivered to end hosts in real time to maintain smooth playback, i.e., the content must be transmitted at a satisfactory rate. In this thesis, we present our research towards a high-quality peer-to-peer live streaming system that utilizes network coding, a novel technique that permits coding at every peer, which has proven benefits in file dissemination applications. To ensure the practicality of our work, it is our imperative objective to conduct all experiments under realistic settings.