First sdkontology F2F meeting Ontology Mediation in SEKT

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First sdk-ontology F2F meeting - Ontology
Mediation in SEKT

• Jos de Bruijn
• Digital Enterprise Research Institute (DERI)
• University of Innsbruck
• jos.de-bruijn_at_deri.ie, deri.at, uibk.ac.at
• 2004-04-06

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Agenda

• The Ontology Mediation problem
• Ontologies 101
• Mapping Patterns 101
• Ontology Mediation in SEKT WP4
• Ontology Mediation Framework
• Generic Use Cases
• Automation in Ontology Mediation
• Tools
• Timeline

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The Problem

• Situation two existing heterogeneous ontologies,
  OA and OB
• Application A only knows about OA, but still
  wants to use data described using OB
• Application C wants a global view of both OA and
  OB

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Ontologies 101

• An ontology consists of
• Concepts
• Relations
• Instances
• Axioms
• All expressed in some logical language

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Mapping Patterns 101

• Elementary Mapping Patterns
• Mapping Concept to Relation
• C(X) -gt R(X,Y)
• Mapping Instance to Concept
• X gt C(X)
• Transforming instance
• C(X) -gt C(f(X))
• Complex Mapping Patterns
• Mapping two Concepts and a Relation to one
  Concept and two Relations
• C1(X), C2(Y), R(X,Y) -gt C3(X), R1(X,Y), R2(X,Y)
• Mapping between two content standards
• Ontology Mappings instantiate Mapping Patterns
  using the source and target ontology

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Ontology Mediation in SEKT WP4

• Survey of existing methods and tools for Ontology
  Merging and Aligning
• Creation of a Framework for Ontology Mediation
• Building an Ontology Mediation Patterns Library
• Developing an Ontology Mediation Service
  Component
• Application of Ontology Mediation to the Case
  Studies
• Refining Ontology Mediation with experiences
  gained in the Case Studies

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Ontology Mediation Framework

• Ontology Language
• Mapping Patterns Specification Language
• Ontology Mapping language
• Ontologies
• Mapping Patterns
• Ontology Mappings
• Data source connectors
• Mapping tool
• Mediation component

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Ontology Mediation Framework (contd)
Ontologies
Mapping Tool
Ontology Language
uses
uses
creates
Data Source Connector
Ontology Mappings
uses
Mapping Language
uses
consists of
Mediation Component
uses
Mapping Patterns
Pattern Language
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Use Cases for Ontology Mediation
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Instance unification
ont0
User/domain/application ontology
I0
Ontology Mappings
ont1
ont2
Source ontologies
I1
I2
Connectors
Real-world object
app1
app2
I2
I1
Data sources
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Instance Transformation
Mapping1
ont1
ont2
I1
Mediation Component
I2
I1
app1
I2
app2
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Other Use Cases

• Query rewriting
• Ontology Merging
• Creating mappings finding similarities between
  ontologies or rather, between ontologies and
  mapping patterns
• Identifying Instance Similarity

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Automation in Ontology Mediation

• Automation in finding Mappings
• Existing approaches in name and structure
  matching
• Using existing lexicons, e.g. WordNet
• Automation in finding similarity between
  instances
• Matching property values

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Possible Automation in Ontology Mediation

• Holds for both automation in finding mappings and
  in finding similarity in instances

Possible automation
Complexity of the mapping
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Typical SEKT scenarios

• Search over different data sources powered by one
  (global) ontology
• Query different data sources from one application
• Mapping between evolving Ontologies

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Ontology Mediation tools

• GUI tool Ontology mapping tool to be developed
  using the Eclipse platform, integrated with the
  other ontology management GUI tools to be
  developed in SEKT
• Run-time component Mediation component, as part
  of the ontology management infrastructure, will
  perform run-time instance transformation and
  unification and query rewriting based on the
  ontology mappings created off-line

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Timeline

• End of April Initial version of use cases and
  scenarios for Ontology Mediation
• End of May Initial versions of the patterns
  library and ontology mediation framework
  (including language) will be available
• End of June State-of-the-art survey (official
  deliverable) on current technologies available
• End of December First real version (official
  deliverables) available for the patterns library
  and the mediation framework
• End of June 2005 First implementation of mapping
  GUI and mediation component