1. Oyster, Edinburgh, May 2006 AIFB OYSTER - Sharing and Re-using Ontologies in a Peer-to-Peer Community Raul Palma 2, Peter Haase 1 1) Institute AIFB, University of Karlsruhe, Germany 2) Ontology Engineering Group, Laboratorio de Inteligencia Artificial. Facultad de Informática. Universidad Politécnica de Madrid May, 2006 metadata standard

2. Oyster, Edinburgh, May 2006 AIFB Motivation Re-use of ontologies often difficult –Where can I find an ontology? –Who has developed a particular ontology? –For which domain / application? –... Metadata Standard required to improve and ensure –Interoperability & exchange –Access & usabilty Standards required for industrial applications

3. Oyster, Edinburgh, May 2006 AIFB Oyster Peer-to-Peer system for sharing and exchanging ontology metadata among communities in the Semantic Web Supports re-use of existing ontologies Exploits semantic web techniques in data representation, query formulation, query routing and query result presentation Implements a proposal for a metadata standard: OMV (Ontology Metadata Vocabulary). The ontology metadata entries are aligned and formally represented according to two ontologies (OMV and topic hierarchy -i.e. DMOZ topic hierarchy-)

4. Oyster, Edinburgh, May 2006 AIFB Ontology Metadata P2P Scenario E A C B F SWRC Ontology in RDFS? @ONTOLOGYDOCUMENT{ title = SWRC-2001, ontologyLanguage =RDFS, creator=OEG and AIFB url = …} AIFB UPM XX D

5. Oyster, Edinburgh, May 2006 AIFB Main functionalities Creating and importing metadata: –Oyster enables users to create metadata about ontologies manually, as well as to import ontology files and to automatically extract the ontology metadata available, letting the user to fill in missing values. Formulating queries: –the user can search for ontologies using simple keyword searches, or using more advanced, semantic searches. Routing queries –the user may query a single specific peer, a specific set of peers, or the entire network of peers, in which case queries are routed automatically in the network. In the latter case, queries are routed through the network depending on the expertise of the peers. Processing results: –the results matching query are presented in a result list, detecting possible duplicates

6. Oyster, Edinburgh, May 2006 AIFB Oyster Architecture & Modules Peer Selection Message Query Replier Query Local Node Repository Communication Adapter JXTA Network Knowledge Source Integration User Interface Answer Informer Knowledge Sources Statements

7. Oyster, Edinburgh, May 2006 AIFB Ontology Metadata Vocabulary in Oyster

8. Oyster, Edinburgh, May 2006 AIFB Ontology Metadata Vocabulary OMV is … a metadata schema –Captures reuse-relevant information about an ontology OMV consists of … core and extensions –OMV Core: fundamental information about an ontology and ist life cycle –OMV Extensions: detailed account on specific phases of an ontology life cycle OMV is designed … as an ontology OMV is implemented…in XML, OWL Lite

9. Oyster, Edinburgh, May 2006 AIFB Ontology Metadata Vocabulary OMV distinguishes between: –An ontology conceptualisation (OC) which represents the abstract or core idea of an ontology, so called conceptualization. It describes the core properties of an ontology, independent from any implementation details. –An ontology implementation (OI), which represents a specific realization of an ontology base. Therefore, it describes properties of an ontology that are related to the realization or implementation.

10. Oyster, Edinburgh, May 2006 AIFB Further Classes: Party – Organisation – Person LicenseModel KM-Method OntologyType OntologySyntax OntologyLanguage OntologyEngineeringTool

11. Oyster, Edinburgh, May 2006 AIFB Main benefits Oyster supports the core idea of the Semantic Web (in particular reuse and sharing of knowledge) and help to increase the applicability of ontologies. Provides the first decentralized knowledge sharing environment that allows developers to exchange ontology metadata. Everyone contributes own ontologies metadata. Everyone profits from own effort (even offline) and the effort of other peers. Always up-to-date with current work of the users (Almost) no administration efforts Provides the benefits from a P2P environment (scalability, fault tolerance, evolutivity, simplicity of design, etc.)

12. Oyster, Edinburgh, May 2006 AIFB Overview Query Scope Semantic Search Integration of Results Entry Details

13. Oyster, Edinburgh, May 2006 AIFB What is planned now? Support distributed metadata management. Evolving metadata automatically and in parallel to the networked ontologies. –Propagation of changes Find ontologies based on trust or context aspects. Support ontology rating Support queries using more OMV concepts Integrate own classification ontologies Integration with other repositories

14. Oyster, Edinburgh, May 2006 AIFB THANKS!