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LOgic Based management of Ontologies

LOgic Based management of Ontologies The LOBO Project IKTA-00126/2002 Facts about the LOBO project Consortium members: IQSOFT Ltd., Hungary, coordinator Budapest University of Technology and Economics, Hungary Semmelweis University, Hungary Duration of the project

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LOgic Based management of Ontologies

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  1. LOgic Based management of Ontologies The LOBO Project IKTA-00126/2002

  2. Facts about the LOBO project • Consortium members: • IQSOFT Ltd., Hungary, coordinator • Budapest University of Technology and Economics, Hungary • Semmelweis University, Hungary • Duration of the project • 1th January, 2003 – 30th September, 2004 • Partly funded by • Research & Development Division, Ministry of Education, Hungary

  3. Research context • LOBO is part of a broader research direction, which aims at creating a logic based tool-set for information integration • The planned stages of development • creation of a tool which supports the integration and mediation of heterogeneous information sources based on the model warehouse approach (SILK project) • extending SILK towards ontology support, management and integration (LOBO project) • using the results in real-world applications

  4. Past work on information integration • SILK – an international research project • supported by IST 5th Framework Programme of the European Union • with the participation of IQSOFT Ltd. (coordinator) and French, Romanian and Greek partners • SILK was successfully concluded in October 2002 • The result of the project is the SILK tool-set, which • supports integration of heterogeneous information sources • uses the model warehouse concept based on UML and OCL • uses constraint and logic programming techniques • supports the comparison, unification and verification of models • provides basic model editing capability • supports mediation and conceptual level queries

  5. The SILK tool-set

  6. Goals of the LOBO project • A logic-based ontology management system, supporting • ontology creation and editing, integration of existing ontologies • knowledge management based on ontologies (verification, comparison, etc.) • ontology based refinement of queries • Pilot applications in the biomedical domain demonstrating the capabilities of the LOBO system • Innovative, logic based, ontology management techniques • use of constraint-logic programming, various verification techniques • storage of large ontologies, version control, unification and comparison methods • support for systems based on the Semantic Web approach and Description Logics, including RDF, DAML+OIL, OWL

  7. Application domains e.g. medical, technical, human M T H information information information Integration of heterogeneous sources Model warehouse LOBO Integrator LOBO Server data data data Ontologies, information sources The LOBO tool-set

  8. Ontologies - 1 • An ontology codifies the explicit body of knowledge in a specific domain and formally describes the intrinsic relations within it • this can be simply some hierarchical information, e.g. „every mammal is animal” or „every human is mammal”, etc. • however it can be more like ,,real background knowledge”, e.g. „nothing can be both Male and Female”; „every person who has favourite brewery drinks beer”, the role ,,ancestor” is transitive, etc. • Potential of Ontologies • ontologies can be used together with traditional information sources to provide better answers, more intelligent consistency checking • ontologies play a significant role in the Semantic Web approach to provide search engines never seen before • In summary: ontologies give semantics to the data sources

  9. Ontologies - 2 • Important issues about ontologies • what kind of formalism is suitable for ontology representation? • we may use UML, together with OCL-t, Description Logics, etc. • in LOBO we decided on using Description Logic • how to link the data source with the appropriate ontology? • this needs complex mapping techniques • how to create unified ontologies? • we need appropriate comparison, unification, verification, etc. techniques • ontologies can be very large • this affects the knowledge representation as well as the reasoning techniques

  10. The SILK ontology challenge • As opposed to UML-based SILK, LOBO should support ontology and object-oriented modeling in a uniform way • Extending SILK to support ontology management • support for ontology modeling languages, such as RDF, DAML+OIL, OWL, etc. • Description Logic based reasoning capabilities • Unifying the corresponding notions of ontology and Object-oriented languages

  11. First Step: RDF connectivity • We have developed an RDF wrapper, with the following functionality • export/import RDF based sources • efficient query language • query optimisation • inference service over the RDF data and schema • verification on the data and schema level • RDF sources are now first class citizens of the SILK/LOBO world • LOBO supports complex queries over heterogeneous data sources which include RDF sources also • LOBO supports comparison/unification/verification of RDF based ontologies

  12. Data Source Data Source Data Source RDF Wrapper Wrapper Wrapper Wrapper r r JDBC JDBC DOM SAX DBMS EXCEL RDF XML RDF wrapper in the LOBO tool-set User Query MEDIATOR Query planning Data Source Wrapper CORBA Func - tions

  13. Second Step: the LORE system • The LORE (Logic based Ontology Reasoner and Editor) tool provides ontology editing, querying and reasoning facilities • supports ontology and data editing • provides „on-the-fly” consistency checking and advice • provides data-level navigation, • supports multiple sources at the same time • Implementation of LORE • it is based on the RDF wrapper • uses SAX parser in order to handle really large ontologies • Systems similar to LORE include • OilED, Protege2000, etc.

  14. LORE – management of ontologies

  15. LORE – querying/editing instances

  16. Summary • The LOBO system (under development) • is a logic based ontology management tool-set • for supporting ontology integration • based on the results of the SILK European Union project • Initial results • full support for RDF based sources • the LORE tool, which is a full featured ontology editor/reasoner • Future plans • full support for Description Logic in LOBO • extend LOBO towards the MDA (Model Driven Architecture) world

  17. ExternalApplications ModellingTools LOBO v2 KnowledgeBroker Information Broker KnowledgeManager Model/Ontology Warehouse KnowledgeExtractor ServiceWrapper(WS) Data Wrapper(XML) Data Wrapper(RDF) DataWrapper(JDBC) … XMLData Sources RDFData Sources JDBCData Sources Web-services … The future of LOBO

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