Multimedia Correlation Analysis in Unstructured Peer-to-Peer Network

Recent years saw the rapid development of peer-topeer (P2P) networks in a great variety of applications. However, similarity-based k-nearest-neighbor retrieval (k-NN) is still a challenging task in P2P networks due to the multiple constraints such as the dynamic topologies and the unpredictable data updates. Caching is an attractive solution that reduces network traffic and hence could remedy the technological constraints of P2P networks. However, traditional caching techniques have some major shortcomings that make them unsuitable for similarity search, such as the lack of semantic locality representation and the rigidness of exact matching on data objects. To facilitate the efficient similarity search, we propose semantic-aware caching scheme (SAC) in this paper. The proposed scheme is hierarchy-free, fully dynamic, non-flooding, and do not add much system overhead. By exploring the content distribution, SAC drastically reduces the cost of similarity-based k-NN retrieval in P2P networks. The performance of SAC is evaluated through simulation study and compared against several search schemes as advanced in the literature

Delay Sensitive Routing For Real Time Traffic Over Ad-hoc Networks

Wireless ad hoc network consists of inexpensive nodes that form a mobile communication network. Due to limitations of the transmission range, the nodes rely on each other to forward packets such that messages can be delivered across the network. The selection of the path along which a packet is forwarded from the source node to the destination node is done by the routing algorithm. Most commonly used routing algorithms, though effective for non-real time applications, cannot handle real-time applications that require strict delay bounds on packet delivery. In this thesis, we propose a routing protocol that ensures timely delivery of real time data packets. The idea is to route packets in such a way that irrespective of factors like traffic load and node density, the average delay remains within acceptable bounds. This is done by carefully accessing the resources available to a route before a session is admitted along that route. Each link in the route is checked for sufficient bandwidth not only for the new session to be admitted but also for the sessions that are already using that link. The new session is admitted only if the admission does not violate the delay bounds of any on-going sessions. This method of route selection coupled with per-hop link reservations allows us to provide bounds on the delay performance. Extensive simulation experiments have been conducted that demonstrate the performance of the proposed routing protocol in terms of throughput, session blocking probability, packet drop probability, average path length, and delay