Two-Level Chord-Ring for Ontology-based Distributed RDF Store

RDF and OWL are used as the data model and schema, respectively, to build the distributed knowledge base of the Semantic Web. The components in RDF models, subjects, predicates, and objects, are identified universally on the web, which makes it suitable for distributed operations. In this paper, we employ the distributed hash table (DHT) technology on peer-to-peer network to develop distributed RDF store. To take into account of ontology in RDF, we extend the chord ring to be two-level ring, where the first level is based on the ontology schema and the next one is on the RDF itself. The extension retains the complexity of O(log N) in maintaining and lookup message in an N-node system. The simulation results show that adding an additional level reduces the path length of message lookup. We design three-layered system architecture for the ontology-based distributed RDF store. We are developing a prototype according to the design in this paper to show how the two-level ring works.