The Ontology Alignment Source
Purpose Ontologies Files Papers

  • Purpose of this Website
  • Ontology alignment is the automated resolution of semantic correspondences between the representational elements of heterogenous sytems. Ontology alignment (including ontology/schema matching/mapping) is a critical technical challenge for the dynamic semantic integration of information resources as well as for ontology-mediated cognitive agent learning.

    The Ontology Alignment Source supports the ontology alignment research community by providing a forum that promotes the sharing and comparison of research data. This site provides access to tools, test data, and metrics for ontology alignment algorithm development and evaluation. We also publish ontology alignment experiment data contributed by members of the research community. This allows for comparson of various ontology alignment opproaches.

    In conjunction with this effort, we organized the I3CON, Information Interpretation and Integration Conference, held in August 2004. We have also participated in the organization of EON, Evaluation of ONtology tools in November 2004, held as part of ISWC 2004 and the Integrating Ontologies Workshop in October 2005, held as part of the Knowledge Capture Conference. Each event involved benchmark experiments that compared the performance of different ontology alignment tools on standard ontology pairs.

    To participate in this research community effort, please email Better yet, join our mailing list!

  • The Alignment Ontologies
  • To facilitate the sharing of research data, we have defined an Ontology Alignment Ontology and an Alignment Evaluation Ontology, along with "upper" ontologies capturing the concepts for the broader category of ontology operations. These ontologies are provided in various ontology formats below.

    • Alignment                     [N3] [OWL]
    • Alignment Evaluation     [N3] [OWL]
    • Ontology Operation      [N3] [OWL]
    • Operation Evaluation     [N3] [OWL]

    In a paper entitled "The Semantics of Ontology Alignment," we explain these ontologies in more detail. We welcome your comments on these ontologies.

  • Alignment Files
  • The above ontologies provide a framework for generating files that declare alignments between elements in heterogeneous ontologies and that reporting evaluations of these alignments. Below are some sample alignment and alignment evaluation files.

  • Links
  • Ontology Alignment is an emerging field of research. There are now a number of projects developing tools and infrastructures for ontology alignment, some of which are listed below.

    Related Projects


    • The Ontology Alignment Source is developed and maintained as part of the Ontology Translation Protocol (Ontrapro) IR&D Program at Lockheed Martin Advanced Technology Laboratories. For more information about Ontrapro, contact Benjamin Ashpole or Todd Hughes.
    • The content of the "Related Projects" section is used with kind permission of Pavel Shvaiko of University of Trento, Italy, who hosts the Ontology Matching site, another excellent resource for those interested in ontology alignment.

Last Updated 2005-12-30