Logic based management of ontologies
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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

The LOBO Project


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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

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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

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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

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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

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Application domains

e.g. medical, technical, human







Integration of heterogeneous sources

Model warehouse

LOBO Integrator

LOBO Server




Ontologies, information sources

The LOBO tool-set

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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

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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

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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

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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

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Data Source

Data Source

Data Source
















RDF wrapper

in the

LOBO tool-set

User Query


Query planning

Data Source






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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.

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  • 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

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Model/Ontology Warehouse



Data Wrapper(XML)

Data Wrapper(RDF)


XMLData Sources

RDFData Sources

JDBCData Sources


The future of