processing complex rdf queries over p2p networks
In large-scale distributed systems, information is typically generated decentralized. However, for many applications it is desirable to have a unified view on this knowledge, allowing to reason about it and to query it without regarding the heterogeneity of the underlying systems. In this context, two main requirements have to be fulfilled. On the one hand, a retrieval system has to be semantically rich, in order to be able to cope with and mediate between different schemas, and on the other hand it has to be scalable to large numbers of information sources. The dynamic nature of information makes the problem even worse.Within this paper, we propose a solution to this problem. We describe a DHT-based peer-2-peer network storing knowledge in the form of RDF triples. The query evaluation algorithm allows to use arbitrary query patterns, and evaluates the query with respect to taxonomical reasoning. Thus the system combines expressivity and scalability. Although we describe the whole system, the focus of this paper is the query evaluation.The system is generic by nature and suitable for numerous different applications. We describe an example application stemming from the Semantic Grid.
rdfs rdfs p2p grid semantic web query processing rdf