1. ISWC2005http://sekt.semanticweb.org/ Reasoning with Multi-version Ontologies: a temporal logic approach Zhisheng Huang and Heiner Stuckenschmidt Vrije University Amsterdam The Netherlands

2. ISWC2005http://sekt.semanticweb.org/ Outline Motivation Framework Temporal logics Examples Prototype of MORE (Multi-version Ontology REasoner) Data Test and Evaluation Conclusion and Future work.

3. ISWC2005http://sekt.semanticweb.org/ Multi-versioning: Why Change Recovery: allow the possibilities for the developers to withdraw or adjust the changes to avoid unintended impacts. Compatibility: Ontology users may prefer an earlier version with less resource requirement to a newer version with higher resource requirement. ……

4. ISWC2005http://sekt.semanticweb.org/ The Idea of Versioning Version Spaces: Models resulting from changes are stored separately Models and change operations form a graphcalled Version Space Data is accessed through the “right” version v1 v3 v2 v4 v6 v5

5. ISWC2005http://sekt.semanticweb.org/ Managing Version Spaces Idea: Enable Administrator to ask questions about the version space Combine Reasoning: Ontologies: DL reasoner (RACER) Version Space: Modal Logic Principle: Each Ontology is a possible world Truth of statements in a state is determine by the DL reasoner

6. ISWC2005http://sekt.semanticweb.org/ Simplifying Assumptions Linear Time Temporal Logic Linear Version Space Operators Conjunction, Negation, PreviousVersion, AllPriorVersions Pre-defined Statement predicates Child-of, parent-of, Any other RACER function..

7. ISWC2005http://sekt.semanticweb.org/ Version Space Version space: A version space S over an ontology set Os is a set of ontology pairs, namely, S  Os × Os. Linear version space: S = {,, · · ·, } such that o i  o j for i  j. alternatively, we write S=(o 1, o 2, …, o n ) Linear ordering: o’< o iff o’ occurs prior to o in the sequence S.

8. ISWC2005http://sekt.semanticweb.org/ Linear Time Logic LTLm Operators: Boolean operators: negation, conjunction, etc. Temporal operators (Backlooking operators) Prev  :  holds in the previous version (PreviousVersion) P  :  holds in a prior version(Sometimes in the past) (SomePriorVersion) H  :  holds in all prior versions (Always in the past) (AllPriorVersions)  S  :  always holds in the prior versions since  holds in a prior version (Since)

9. ISWC2005http://sekt.semanticweb.org/ Semantics

10. ISWC2005http://sekt.semanticweb.org/ Formal Properties H  -> P . H  -> Prev . Prev  -> P . Prev P  -> P . P P  -> P . H H  -> H . Prev Prev  -> P .

11. ISWC2005http://sekt.semanticweb.org/ Reasoning Queries  :  holds in the current version   Prev  :  holds in the current version but not in the previous version.   P  : incompactible (with respect to  ).   H  :  holds only in the current version, it never holds before.

12. ISWC2005http://sekt.semanticweb.org/ Reasoning Query: stable change Once  is changed, it is never changed again.   S (H  ).

13. ISWC2005http://sekt.semanticweb.org/ Change Accounting: Only Twice  is changed only twice.   S Prev(  S H   ).

14. ISWC2005http://sekt.semanticweb.org/ Change Accounting: Only N times Change(1,  ) = df   S H . Change(n,  ) = df   S Prev(Change (n-1,   )).

15. ISWC2005http://sekt.semanticweb.org/ Reasoning Query: last version I  holds at the last version in which  holds.  S (Prev(   ))

16. ISWC2005http://sekt.semanticweb.org/ Reasoning Query: last version II  holds at the last version in which  does not hold before a version  holds.   S (Prev(  S Prev(     ))).

17. ISWC2005http://sekt.semanticweb.org/ Retrieval Queries child, parent concept relation

18. ISWC2005http://sekt.semanticweb.org/ Relative Versioning Version 0   . (the current version) Version -i   Prev ( Version -(i-1)  )

19. ISWC2005http://sekt.semanticweb.org/ Absolute Versioning Version ( i,S)   Version i-n  where |S|=n

20. ISWC2005http://sekt.semanticweb.org/ Retrieval Query

21. ISWC2005http://sekt.semanticweb.org/ The MORE System Milestone 3.5 – Software Prototype. Prototype: MORE (Multi-version Ontology REasoner) MORE website: http://wasp.cs.vu.nl/sekt/more

22. ISWC2005http://sekt.semanticweb.org/ The MORE System Functionality Temporal Reasoning Queries Ontology Comparison Queries: Versioning Retrieval Queries Ontology Data format: OWL and DIG Test Data BioSAIL ontologies (3 versions) SEKT legal case study ontologies (5 versions)

23. ISWC2005http://sekt.semanticweb.org/ A Query Answer

24. ISWC2005http://sekt.semanticweb.org/ Test Result: Change Log

25. ISWC2005http://sekt.semanticweb.org/ Conclusions A framework of multi-version ontology reasoning Temporal logic approach Expressive power of LTLm Semantic differences on multi-version ontologies.

26. ISWC2005http://sekt.semanticweb.org/ Future Work Integrating MORE with ontology evolution (Dynamic logic approach). Branching time version space.