1. December 1, 2006 Florencehttp://www.sekt-project.com/ 1 Dynamic Aspects of SEKT Legal Ontologies Zhisheng Huang, Stefan Schlobach, Frank van Harmelen Vrije University Amsterdam Nuria Casellas and Pompeu Casanovas Universitat Autonoma de Barcelona

2. December 1, 2006 Florencehttp://www.sekt-project.com/ 2 Outline SEKT Legal Ontologies Ontology Versioning: Motivation Prototype of MORE (Multi-version Ontology REasoner) Quantitative/Qualitative Analysis Conclusion

3. December 1, 2006 Florencehttp://www.sekt-project.com/ 3 SEKT Legal Case Study Design an intelligent system to help new judges with their practical problems: Intelligent FAQ system using Semantic Web technologies Connect the iFAQ system with the existing judgments

4. December 1, 2006 Florencehttp://www.sekt-project.com/ 4 Ontologies used in Legal Case OPJK (Ontology of Professional Judicial Knowledge) 104 classes, 567 instances Topic ontologies: QTO (Questions Topic Ontology) 17 topics JTO (Judgments Topic Ontology) 30 topics. Judgment Ontology 15 terms, integrated in PROTON See Mercedes’ talk tomorrow for details.

5. December 1, 2006 Florencehttp://www.sekt-project.com/ 5 OPJK and Versioning Modelled from the questions extracted from the ethnographic survey Aprox. 850 questions, 700 terms OPJK was being built extracting relevant concepts and relations from one question at a time (grouped in subdomains) There are a lot of versions as additions took place and modifications were required during modeling for keeping track of OPJK for it's changes.

6. December 1, 2006 Florencehttp://www.sekt-project.com/ 6 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. Change Tracking: Keep track of ontology changes.

7. December 1, 2006 Florencehttp://www.sekt-project.com/ 7 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

8. December 1, 2006 Florencehttp://www.sekt-project.com/ 8 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

9. December 1, 2006 Florencehttp://www.sekt-project.com/ 9 Abstract Use Cases Semantic Change Log (Temporal logic) Summary of changes in the deductive closure Compatibility Checking (Temporal logic) Compare results of queries against expected answers Version Selection (Hybrid Logic) Check versions for certain required statements Version Planning (Dynamic Logic) Simulate the impact of possible changes

10. December 1, 2006 Florencehttp://www.sekt-project.com/ 10 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..

11. December 1, 2006 Florencehttp://www.sekt-project.com/ 11 Linear Time Logic LTLm Operators: Boolean operators: negation, conjunction, etc. Temporal operators (Backlooking operators) Prev  :  holds in the previous version P  :  holds in a prior version(Sometimes in the past) H  :  holds in all prior versions (Always in the past)  S  :  always holds in the prior versions since  holds in a prior version

12. December 1, 2006 Florencehttp://www.sekt-project.com/ 12 Semantics

13. December 1, 2006 Florencehttp://www.sekt-project.com/ 13 Reasoning Queries  :  holds in the current version   Prev  :  holds in the current version but no in the previous version.   P  : incompactible (with respect to  ).   H  :  holds only in the current version, it never holds before.

14. December 1, 2006 Florencehttp://www.sekt-project.com/ 14 Reasoning Query: stable change Once  is changed, it is never changed again.   S (H  ).

15. December 1, 2006 Florencehttp://www.sekt-project.com/ 15 Reasoning Query: last version I  holds at the last version in which  holds.  S (Prev(   ))

16. December 1, 2006 Florencehttp://www.sekt-project.com/ 16 Effect Space Effect space is the set of all possible semantic relations in a version space. In MORE, we consider effect spaces which are characterized by the new/obsolete/invariant relation on concepts/roles/individu als on a version space.

17. December 1, 2006 Florencehttp://www.sekt-project.com/ 17 Retrieval Queries child/parent/descendant/ancestor concept relations

18. December 1, 2006 Florencehttp://www.sekt-project.com/ 18 The MORE System Functionality Temporal Reasoning Queries Ontology Comparison Queries: Versioning Retrieval Queries Ontology Data format: OWL, RDF/RDFS and DIG http://wasp.cs.vu.nl/sekt/more

19. December 1, 2006 Florencehttp://www.sekt-project.com/ 19 Dynamic Aspect: New

20. December 1, 2006 Florencehttp://www.sekt-project.com/ 20 Dynamic Aspect: Stability

21. December 1, 2006 Florencehttp://www.sekt-project.com/ 21 Dynamic Aspect: Nonmonotonicity

22. December 1, 2006 Florencehttp://www.sekt-project.com/ 22 New at Concept Level

23. December 1, 2006 Florencehttp://www.sekt-project.com/ 23 Stability at Concept Level

24. December 1, 2006 Florencehttp://www.sekt-project.com/ 24 Qualitative Evaluation I Stable change of OPJK:   S (H  ).  descendant(Fuerzas_de_Orden_Público, Objeto) S (H descendant(Fuerzas_de_Orden_Público, Objeto) ).

25. December 1, 2006 Florencehttp://www.sekt-project.com/ 25 Qualitative Evaluation II Last version detection:  S (Prev(   ))  descendant(Fuerzas_de_Orden_Público, Organización) S (Prev descendant(Fuerzas_de_Orden_Público, Organización)  descendant(Organización, Grupo)).

26. December 1, 2006 Florencehttp://www.sekt-project.com/ 26 Conclusions We studied the properties of the overall versioning space by checking for stability, novelty and monotonicity of the process. More detailed analysis on dynamic aspects at concept level We provided an initial case study on the stability of change in the versioning space using the power of the temporal logic which underlies MORE.