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Integrating RDF Ontologies


RDF ontologies are rapidly increasing in number. We study the problem of integrating two RDF ontologies under a given set of Horn clauses that specify semantic relationships between terms in the ontology, as well as under a given set of negative constraints. We formally define the notion of a "witness" to the integrability of two RDF ontologies under such constraints. A witness represents a way of integrating the ontologies together. We define a "minimal" witnesses and provide the polynomial CROW (Computing RDF Ontology Witness) algorithm to find a witness.

We report on the performance of CROW both on DAML, SchemaWeb and OntoBroker ontologies as well as on synthetically generated data. The experiments show that CROW works very well on real-life ontologies and scales to massive ontologies.

An extended version of CROW that works for a large number of quality measures for the integrated ontology is currently being developed. Specifically, different domains may have interest in preserving particular aspects of the original ontology - such as the extensions for certain properties or classes, etc. Our goal is to allow the user to specify the quality measure for the integration results as a function that has to meet certain reasonable axioms.


Octavian Udrea, Yu Deng, Edna Ruckhaus, V.S. Subrahmanian


  1. Octavian Udrea, Yu Deng, Edna Ruckhaus, V.S. Subrahmanian, A Graph Tehoretical Foundation for Integrating RDF Ontologies in Proccedings of the Twentieth National Conference on Artificial Intelligence, 2005, pp. 1442-1447 [PDF]

Demos and talks

  1. CROW Poster can be found here

  2. A video demonstration of CROW can be found here (WMV, ~5.2 MB).
Last updated: March 26 2008
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