China.2005http://sekt.semanticweb.org/ Reasoning with Multi-version Ontologies: a temporal logic approach Zhisheng Huang and Heiner Stuckenschmidt Vrije University Amsterdam The Netherlands (ISWC05 paper)

China.2005http://sekt.semanticweb.org/ Outline Motivation Framework Temporal logics Examples Prototype of MORE (Multi-version Ontology REasoner) Data Test and Evaluation Conclusion and Future work.

China.2005http://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. ……

China.2005http://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

China.2005http://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

China.2005http://sekt.semanticweb.org/ 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

China.2005http://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..

China.2005http://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.

China.2005http://sekt.semanticweb.org/ 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

China.2005http://sekt.semanticweb.org/ Linear Time Logic LTLm(F) Operators: Temporal operators (forward-looking operators) Next  :  holds in the next version F  :  holds in a sequel version(Sometimes in the future) G  :  holds in all sequel versions (Always in the future)  U  :  always holds in all of the sequel versions until  holds.

China.2005http://sekt.semanticweb.org/ Semantics

China.2005http://sekt.semanticweb.org/ Semantics S, o |= Prev  iff  S and S, o’ |= . S, o |= H  iff  o’< o and S, o’ |= . S, o |=  S  iff  o 1, …, o n (, …,  S and o n =o and S, o i |=  and S, o 1 |= 

China.2005http://sekt.semanticweb.org/ Formal Properties H  -> P . H  -> Prev . Prev  -> Past . Prev P  -> P . P P  -> P . H H  -> H . Prev Prev  -> P .

China.2005http://sekt.semanticweb.org/ 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.

China.2005http://sekt.semanticweb.org/ Reasoning Query: stable change Once  is changed, it is never changed again.   S (H  ).

China.2005http://sekt.semanticweb.org/ Change Accounting: Only Twice  is changed only twice.   S Prev(  S H   ).

China.2005http://sekt.semanticweb.org/ Change Accounting: Only N times Change(1,  ) = df   S H . Change(n,  ) = df   S Prev(Change (n-1,   )).

China.2005http://sekt.semanticweb.org/ Reasoning Query: last version I  holds at the last version in which  holds.  S (Prev(   ))

China.2005http://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(     ))).

China.2005http://sekt.semanticweb.org/ Retrieval Queries child, parent concept relation

China.2005http://sekt.semanticweb.org/ Relative Versioning Version 0   . (the current version) Version -i   Prev ( Version -(i-1)  )

China.2005http://sekt.semanticweb.org/ Absolute Versioning Version ( i,S)   Version i-n  where |S|=n

China.2005http://sekt.semanticweb.org/ Retrieval Query

China.2005http://sekt.semanticweb.org/ The MORE System Milestone 3.5 – Software Prototype. Prototype: MORE (Multi-version Ontology REasoner) MORE website:

China.2005http://sekt.semanticweb.org/ An Extended DIG Description Logic Interface for Prolog (XDIG) A logic programming infrastructure for the Semantic Web Similar to SOAP Application independent, platform independent Support for DIG clients and DIG servers.

China.2005http://sekt.semanticweb.org/ XDIG As a DIG client, the Prolog programs can call any external DL reasoner which supports the DIG DL interface. As a DIG server, the Prolog programs can serve as a DL reasoner, which can be used to support additional reasoning processing, like inconsistency reasoning multi-version reasoning, and inconsistency diagnosis and repair.

China.2005http://sekt.semanticweb.org/ XDIG package The XDIG package and the source code are now available for public download at the website: In the package, we offer five examples how XDIG can be used to develop extended DL reasoners.

China.2005http://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)

China.2005http://sekt.semanticweb.org/ Test Result: Change Log

China.2005http://sekt.semanticweb.org/ Conclusions A framework of multi-version ontology reasoning Temporal logic approach Expressive power of LTLm Semantic differences on multi-version ontologies.

China.2005http://sekt.semanticweb.org/ Future Work Integrating MORE with ontology evolution (Dynamic logic approach). Hybrid logic approach for nominals Branching time version space. Merging time model (merging multiple ontologies).