A Resource Discovery Scheme Based On RDF In P2P Networks

P2P has been a hot topic in computer science. However, efficient resource discovery is difficult because P2P networks are large and dynamic. Up to now, most P2P networks have implemented keyword-based resource discovery schemes without enough support on semantic based resource discovery. Therefore, how to achieve efficient and accurate semantic based resource discovery in large and dynamic P2P environment is an interesting problem.To address this problem, following works have been done this paper:1. A RDF based resource description and discovery scheme in P2P networks is designed, which is named PeerRDF.PeerRDF uses double-layer topology, in which super nodes serve as proxies for leaf nodes. The RDF based resource description documents and queries are first mapped into the DHT routing spaces of super nodes, after which DHT routing and lookup protocols are used to reach register nodes efficiently among all super nodes. A theretical model has also been put forward as well as performance indices to compare PeerRDF with other schemes.2. A mapping method is put forward to map RDF based resource description documents and queries into DHT routing spacesThe method is designed to extract hash strings from resource descriptions and path expressions to establish mappings from RDF description & queries to routing spaces of DHT networks, which enables DHT network formed by super nodes in PeerRDF to support semantic level queries against resources.3. Simulation studies of PeerRDFPerformance of PeerRDF is studied through simulation study. A simulation engine is designed and implemented, and simulation parameters are setting according to real situations and similar studies. The results show that PeerRDF outperform other schemes on time and network overhead.