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Blank Node Matching and RDF/S Comparison Functions

  • Yannis Tzitzikas
  • Christina Lantzaki
  • Dimitris Zeginis
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7649)

Abstract

In RDF, a blank node (or anonymous resource or bnode) is a node in an RDF graph which is not identified by a URI and is not a literal. Several RDF/S Knowledge Bases (KBs) rely heavily on blank nodes as they are convenient for representing complex attributes or resources whose identity is unknown but their attributes (either literals or associations with other resources) are known. In this paper we show how we can exploit blank nodes anonymity in order to reduce the delta (diff) size when comparing such KBs. The main idea of the proposed method is to build a mapping between the bnodes of the compared KBs for reducing the delta size. We prove that finding the optimal mapping is NP-Hard in the general case, and polynomial in case there are not directly connected bnodes. Subsequently we present various polynomial algorithms returning approximate solutions for the general case.

For making the application of our method feasible also to large KBs we present a signature-based mapping algorithm with n logn complexity. Finally, we report experimental results over real and synthetic datasets that demonstrate significant reductions in the sizes of the computed deltas. For the proposed algorithms we also provide comparative results regarding delta reduction, equivalence detection and time efficiency.

Keywords

Resource Description Framework Comparison Function Synthetic Dataset Edit Distance Subgraph Isomorphism 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Yannis Tzitzikas
    • 1
    • 2
  • Christina Lantzaki
    • 1
    • 2
  • Dimitris Zeginis
    • 1
    • 2
  1. 1.Computer Science DepartmentUniversity of CreteGreece
  2. 2.Institute of Computer ScienceFORTH-ICSGreece

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