Query Processing in Ontology-Based Peer-to-Peer Systems

  • Heiner Stuckenschmidt
  • Frank van Harmelen
  • Fausto Giunchiglia
Conference paper
Part of the Whitestein Series in Software Agent Technologies book series (WSSAT)


The unstructured, heterogeneous and dynamic nature of the Web poses a new challenge to query-answering over multiple data sources. The so-called Semantic Web aims at providing more and semantically richer structures in terms of ontologies and meta-data. A problem that remains is the combined use of heterogeneous sources. In a dynamic environment, it is no longer realistic to assume that the involved data sources act as if they were a single (virtual) source, modelled as a global schema, as is done in classical data integration approaches. In this paper, we propose an alternative approach where we replace the role of a single virtual data source schema with a peer-to-peer approach relying on limited shared (or: overlapping) vocabularies between peers. Since overlaps between vocabularies of peers will be limited and the dynamic nature of the system prohibits the design of accurate mappings, query processing will have to be approximate. We provide a formal model for such approximate query processing based on limited shared vocabularies between peers, and we show how the quality of the approximation can be adjusted in a gradual manner. The result is a flexible architecture for query-processing in heterogenous and dynamic environments, based on a formal foundation. We present the approach and discuss it on the basis of a case study.


Semantic web methods and formalisms for knowledge sharing knowledge-based mediation architectures 


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Copyright information

© Birkhäuser Verlag 2005

Authors and Affiliations

  • Heiner Stuckenschmidt
    • 1
  • Frank van Harmelen
    • 1
  • Fausto Giunchiglia
    • 2
  1. 1.Department of Mathematics and Computer ScienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
  2. 2.Department of Information and Communication TechnologyUniversity of TrentoPovo di TrentoItalia

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