China.2005 http://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.2005 http://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.2005 http://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.2005 http://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.2005 http://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.2005 http://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.2005 http://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.2005 http://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 = {<o1, o2>, <o2, o3>, · · · , <on−1, on>} such that oi oj for i j.alternatively, we write
S=(o1, o2, …, on)
• Linear ordering: o < o’ iff o’ occurs prior to o in the sequence S.
China.2005 http://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.2005 http://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.2005 http://sekt.semanticweb.org/
Semantics
China.2005 http://sekt.semanticweb.org/
Semantics
• S, o |= Prev iff <o’, o> S and S, o’ |= .
• S, o |= H iff o’< o and S, o’ |= .
• S, o |= S iff o1, …, on (<o1, o2>, …,<on-1, on> S and on=o and S, oi |= and S, o1|=
China.2005 http://sekt.semanticweb.org/
Formal Properties
• H -> P .
• H -> Prev .
• Prev -> Past .
• Prev P -> P .
• P P -> P .
• H H -> H .
• Prev Prev -> P .
China.2005 http://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.2005 http://sekt.semanticweb.org/
Reasoning Query: stable change
• Once is changed, it is never changed again.
S (H).
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Change Accounting: Only Twice
is changed only twice.
S Prev( S H).
China.2005 http://sekt.semanticweb.org/
Change Accounting: Only N times
• Change(1, ) =df S H.
• Change(n, ) =df S Prev(Change(n-1,)).
China.2005 http://sekt.semanticweb.org/
Reasoning Query: last version I
holds at the last version in which holds .
S (Prev( ))
China.2005 http://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.2005 http://sekt.semanticweb.org/
Retrieval Queries
• child, parent concept relation
China.2005 http://sekt.semanticweb.org/
Relative Versioning
• Version0 . (the current version)
• Version-i Prev(Version -(i-1) )
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Absolute Versioning
•Version(i,S) Version i-n
where |S|=n
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Retrieval Query
China.2005 http://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
China.2005 http://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.2005 http://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.2005 http://sekt.semanticweb.org/
XDIG package
• The XDIG package and the source code are now available for public download at the website: http://wasp.cs.vu.nl/sekt/dig/
• In the package, we offer five examples how XDIG can be used to develop extended DL reasoners.
China.2005 http://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)
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Test Result: Change Log
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Conclusions
• A framework of multi-version ontology reasoning
• Temporal logic approach
• Expressive power of LTLm
• Semantic differences on multi-version ontologies.
China.2005 http://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).