1 Developing an Ontology of Ontologies for OOR Ontology Summit 2008 April 28-29, 2008 Michael Gruninger and Pat Hayes

2 Challenge Identify metadata for ontologies that supports the sharing and reuse of ontologies within open ontology repositories.

3 Ontology Framework The output of last year's Summit was a framework for characterizing the menagerie of artefacts that people refer to as "ontology". The goal was to allow diversity without divergence. Such a framework should minimally allow us to compare different ontologies along various dimensions. –What are the possible "values" that an ontology can take along a particular dimension? The description of any ontology in this framework constitutes metadata for the ontology. To the extent that we have a common shared set of metadata, we have an "Ontology of Ontologies".

4 Uses of Ontology Metadata The metadata should allow users to –retrieve ontologies for use in domain applications; –retrieve ontologies to be integrated with other user ontologies; –retrieve ontologies that will be extended to create new user ontologies; –determine whether or not an ontology can be integrated with user ontologies; –determine whether a set of ontologies retrieved from the repository can be used together; –determine whether an ontology in the repository can be partially shared.

5 Approaches Logical metadata –logical properties of the ontology independent of any implementation or engineering artefact Ontology representation language Modularity Relationships between ontologies Engineering metadata –properties of the ontology as considered as an engineering artefact

6 Keeping Grounded … Start collecting ontologies from Summit participants, and test out the different proposals for metadata on these ontologies. Develop scenarios that will motivate the use of the adequacy of proposed metadata Some existing approaches: –Ontology Metadata Vocabulary (OMV) –Ontoselect

7 Example Scenario Alice wants to design an ontology to be used to support interoperability of scheduling software systems. –She needs a time ontology, a process ontology, and a resource ontology –She finds several time ontologies (including OWL-Time and Catalog of Temporal Theories), several process ontologies (including PSL), and a folksonomy of machines and materials What does Alice need to know about these ontologies and their relationships?

8 Who are the Users? Ontology designers Ontology application developers Ontology infrastructure developers

9 Some Questions Suppose that we are considering a particular ontology in the repository. What is this ontology about? How has this ontology been used? Which other ontologies reuse this ontology? Which other ontologies does this ontology reuse? What "body of knowledge" was used in the design of the ontology? What are alternatives to this ontology? Do there exist implementations of this ontology in different languages? –If so, how are these implementations related to each other?