Ontology Evolution within Ontology Editors

1
Ontology Evolution within Ontology
Editors Presentation at EKAW, Sigüenza, October
2002
L. Stojanovic, B. Motik FZI Research Center for
Information Technologies at the University of
Karlsruhe, Germany
2
Agenda

• Introduction
• Requirements
• Evaluation
• Conclusion

3
Introduction

• Ontology editors are main tools for ontology
  development
• Ontologies must be able to evolve for a number of
  reasons, including the following
• Application domains and users needs are changing
• System can be improved
• An ontology editor has to support ontology
  evolution

4
Agenda

• Introduction
• Requirements
• Evaluation
• Conclusion

5
Requirements for Ontology Evolution

• Functional requirement
• Users supervision requirement
• Transparency requirement
• Reversibility requirement
• Auditing requirement
• Ontology refinement requirement
• Usability requirement

6
Functional requirement

• specifies which functionality must be provided
  for the ontology development and evolution
• depends on the underlying ontology model

7
Functional requirement

• Composite changes
• They are more powerful
• They have coarser granularity
• They have often more meaningful semantics
• e.g. Move_Concept ? (RemoveSubConcept
  AddSubConcept)

8
Functional requirement
9
Users supervision requirement
- enables the user-driven process of change
resolving

• Critical situations
• how to handle orphaned concepts
• how to handle orphaned properties
• how to propagate properties to the concept whose
  parent changes
• what constitutes a valid domain of a property
• what constitutes a valid range of a property
• whether a domain (range) of a property can
  contain a concept that is at the same time a
  subconcept of some other domain (range) concept
• the allowed shape of the concept hierarchy
• the allowed shape of the property hierarchy
• must instances be consistent with the ontology.

10
Transparency requirement

• - provides a human-computer interaction for
  evolution by
• presenting change information in an orderly way
• allowing easy spotting of potential problems
• alleviating the understanding of the scope of
  the change

11
Reversibility requirement
- states that an ontology editor has to allow
undoing changes at the users request
Remove Concept Add Concept
12
Auditing requirement

• - allows inspecting the performed changes by
• keeping a detailed log of all performed changes
• associating meta information with each log
  change
• tracking the identity of the change author

13
Ontology refinement requirement
Structure-driven exploits a set of heuristics to
improve an ontology based on the analysis of the
ontology structure
Data-driven - detects the changes based on the
analysis of the ontology instances
If no instance of a concept C use any of the
properties defined for C, but only properties
inherited from the parent concept, we can make an
assumption that C is not necessary.
Usage-driven takes into account the usage of
the ontology
By tracking when entity has last been retrieved
by a query, it may be possible to discover that
some entities are out of date
14
Usability requirement

• - states that an ontology editor should
• be ergonomically correct to minimise human
  errors
• detect logical conflicts (verification)
• provide the means for validation

15
Agenda

• Introduction
• Requirements
• Evaluation
• Conclusion

16
Evaluation
- - no support ltgt partial support -
full support
17
Agenda

• Introduction
• Requirements
• Evaluation
• Conclusion

18
Conclusion

• Ontology editors should
• enrich the list of possible changes
• enable the customisation of the change resolving
• inform the user about all effects of a change
• allow undoing changes
• allow inspecting the performed changes
• suggest the user to generate a change
• identify inconsistency and provide answers to the
  questions such as how, why, what if, etc.

19
http//kaon.semanticweb.org
20
Thanks! Any questions?
L. Stojanovic, B. Motik FZI Research Center for
Information Technologies at the University of
Karlsruhe, Germany http//wim.fzi.de/wim