Using the DIG Plugin to Reason with Ontologies in LarKC Zhisheng Huang, Gaston Tagni, and Frank van

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Using the DIG Plug-in to Reason with Ontologies
in LarKC Zhisheng Huang, Gaston Tagni,and
Frank van HarmelenVrije University Amsterdam
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Motivation

• All popular DL-reasoners such as RACER, FACT,
  Pellet, KAON2) support the DIG interface.
• The LarKC platform needs DL/OWL reasoning
  support. It is convenient for the platform to
  gain the DL reasoning support via the LarKC DIG
  interface.
• To provide an easy approach to wrap
  non-java-based reasoners (such as PION, MORE,
  DION, etc.) and use them through their DIG
  interface.

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LarKC Platform and the DIG plug-in
Racer
FACT
LarKC Platform
KAON2
DIG Interface Plug-in
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Tasks of the DIG Plug-in

• Translate a set of statements (ontology data)
  into DIG data format. If it is OWL-DL data, it
  uses the OWL2DIG library to translate it into DIG
  data.
• Translate SPARQL(DL) query into DIG
• - deal with triple-encoded DL
  expressions
• 3. Query processing and answer checking
• 4. Translate DIG answers into SPARQL answers

05/27/09
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LarKC Platform and the DIG plug-in
Ontology (URI)/ Set of Statements
SPARQL query
SPARQL Answer
LarKC Platform
Tell
External DIG Reasoner
DIG Interface Plug-in
Ask
Response
LarKC Pipeline The DIG plug-in is implemented as
a Reasoner plug-in
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The DIG plug-in (v0.3)

• Currently supports
• The DIG interface v1.1.
• Sparql ASK and Sparql SELECT.
• DL Expressions (conjunction, disjunction,
  disjoint, negation)
• DIG queries (subsumption, instance, instances)
• Have been tested with
• Racer1.7.14
• PION 2.1.0
• To be supported soon
• Complex DL concept expressions (such as nominal,
  min, max, etc.)
• Complex Sparql expressions (such as Filtering,
  Optional, Regular expressions, sparqlconstruct,
  sparqldescribe, etc.)
• Complex DIG queries (role query, functional
  query, value pair query)

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Why SPARQL-DL?

• SPARQL is too expressive for a DL reasoner.
• In SPARQL, there is no semantic interpretation
  for DL expressions such as owlsameas,
  owldisjointwith, etc.
• SPARQL-DL is a DL-specific SPARQL with some DL
  primitives, such as type(a, C), SubClassof(C1,
  C2), DisjointWith(C1,C2), ComplementOf(C1,C2),Equi
  valentClass(C1,C2),(Sirin and Parsia 2007)

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Translation of DL expressions into RDF triples

• Using the OWL-DL method (Patel-Schneider,Hayes,
  Horrocks 2004).
• http//www.w3.org/TR/owl-semantics/mapping.html

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SPARQL-DL Query Example 1

• ?- subClassOf(Wine, PotableLiquid)
• // to ask whether or not wine is a subclass of
  potable liquid
• PREFIX
• ASK
• WHERE
• wineWine rdfssubClassOf foodPotableLiquid.

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SPARQL-DL Query Example 2
?- subClassOf(Bordeaux, and(SweetWine,
TableWine)) // to ask whether or not Bordeaux is
a SweetWine and TableWine ASK WHERE
wineBordeaux rdfssubClassOf _x.
_x owlinterSectionOf _y1.
_y1 rdffirst wineSweetWine.
_y1 rdfrest wineTableWine.
wineBordeaux rdftype owlClass.
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Simple SPARQLSelect Query Example 3
?- subClassOf(?X, Wine) // to list all
subconcepts of Wine SELECT ?X WHERE ?X
rdfssubClassOf wineWine.
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SPARQL-DL Query Example 4
?- subClassOf(Bordeaux, ?X), subClassOf(?X,Wine),
subClassOf(?X,?Y). SELECT ?X ?Y WHERE
wineBordeaux rdfssubClassOf ?X. ?X
rdfssubClassOf wineWine. ?X
rdfssubClassOf ?Y. ?Y rdftype
owlClass.
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PION

• PION is a system which can get meaningful answers
  when querying oninconsistent ontologies.
• PION website http//wasp.cs.vu.nl/sekt/pion
• The LarKC DIG plugin requires the external PION
  system (version 2.1.0 or higher) with SWI-Prolog
  on your computer (swi-prolog.org).

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PION and External DIG Reasoner

• PION needs an external DIG Reasoner for standard
  reasoning(i.e., non-inconsistency reasoning)

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Various Strategies

• You can use the PION testbed page piontest2.htm
  to select different strategies for reasoning
  with inconsistent ontologies by PION
• selection functions (syntactic relevance, concept
  syntactic relevance, or semantic relevance by
  google distances),
• over-determed processing methods (first maximal
  consistent set, or path pruning with Google
  distances),
• extension strategies (linear extension or
  k-extension).