Dynamic Aspects of SEKT Legal Ontologies

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 http://www.sekt-project.com/

2. Outline • SEKT Legal Ontologies • Ontology Versioning: Motivation • Prototype of MORE (Multi-version Ontology REasoner) • Quantitative/Qualitative Analysis • Conclusion http://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 http://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. http://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. http://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. http://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 v4 v2 v5 v3 v1 v6 http://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 http://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 http://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.. http://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 http://www.sekt-project.com/

12. Semantics http://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. http://www.sekt-project.com/

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

15. Reasoning Query: last version I •  holds at the last version in which  holds .  S (Prev( )) http://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/individuals on a version space. http://www.sekt-project.com/

17. Retrieval Queries • child/parent/descendant/ancestor concept relations http://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 http://www.sekt-project.com/

19. Dynamic Aspect: New http://www.sekt-project.com/

20. Dynamic Aspect: Stability http://www.sekt-project.com/

21. Dynamic Aspect: Nonmonotonicity http://www.sekt-project.com/

22. New at Concept Level http://www.sekt-project.com/

23. Stability at Concept Level http://www.sekt-project.com/

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