collaborative semantic web applications and linked justifications
TRANSCRIPT
Linking Justifications in the Collaborative Semantic Web Applications
Rakebul Hasan and Fabien Gandon, INRIA
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Outline
• Context• Linked Justifications• The Ratio4TA Vocabulary• An Example Scenario• Related Work• Future Work
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Collaborative Semantic Web Platforms
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84 articles modified per minute
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DBpedia-Live keeps DBpedia in synchronization with Wikipedia
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Ever changing interlinked dataspace
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• Results are difficult to understand by the end users
• Applications need to provide explanations along with the flow of information
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• Justification: metadata about why a conclusion has been drawn
• Justifications themselves can be RDF data distributed across the Web
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Linked Justifications
• Applying the very approach of linked data to publish justifications– Use URIs as names of things (justifications and
their components)– Use HTTP URIs– Provide useful information on lookups– Include links to the related URIs
(justifications/resources)
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• Abstraction of justifications to provide explanation; navigation between explanations
• Tracing the origin of inferences– DBPedia live and the chains of dependent
inferences
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The Ratio4TA Vocabularyhttp://ns.inria.fr/ratio4ta/v1/
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An Example Scenario
AcadWiki:Bob
AcadWiki:ComputerScientistrdf:type
AcadWiki:Scientistrdf:type
rdfs:subClassOf
GeoWiki:London
GeoWiki:UnitedKingdom
GeoWiki:isPartOf
GeoWiki:England
GeoWiki:isPartOf
AcadWiki:birthPlace
AcadWiki:birthPlace
GeoWiki
AcadWiki
GeoWiki:isPartOf
AcadWiki:birthPlace
Academician Locator
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Data
Justifications
AcadWiki:Scientist AcadWiki:ComputerScientistrdfs:subClassOf
AcadWiki:Bob AcadWiki:ComputerScientistrdf:type
AcadWiki:Bob GeoWiki:LondonAcadWiki:birthPlace
AcadWiki:Bob AcadWiki:Scientistrdf:type
r4ta:justifies r4ta:justifies
r4ta:antecedentr4ta:antecedent
r4ta:justifies
r4ta:justifies
AcadWiki:Bob GeoWiki:UnitedKingdomAcadWiki:birthPlace
r4ta:justifies
r4ta:antecedent
GeoWiki:London GeoWiki:UnitedKingdomGeoWiki:isPartOf
r4ta:justifiesr4ta:antecedent
AcadWiki
GeoWiki
Academician Locator
Bob’s birthplace is UK because Bob was born in
London and London is part of UK
London is part of UK because London is part of
England and England is part of UK
Bob was born in London
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• Named graphs– Referencing triples/graphs– Grouping justification related triples
J. J. Carroll, C. Bizer, P. Hayes, and P. Stickler. Named graphs, provenance and trust. In Proceedings of the 14th international conference on World Wide Web, WWW ’05, pages 613–622, New York, NY, USA, 2005. ACM.
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#graph for an inferred triple aloc:t1 { AcadWiki:Bob AcadWiki:birthPlace GeoWiki:UnitedKingdom.}
#graph justifying the assertion of an inferred triple aloc:j1 { aloc:j1 rdf:type Justification. aloc:j1 r4ta:justifies aloc:t1. aloc:j1 r4ta:antecedent AcadWiki:j4. aloc:j1 r4ta:antecedent GeoWiki:j1. aloc:t1 rdf:type r4ta:InferredAssertion. aloc:t1 r4ta:inferredByRule aloc:pobRule.}
Link to the triple
Link to justifications
Link to rule
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Example SPIN Rule
• Explanation for RDFS– Type propagation– Property property propagation– subClassOf transitivity – subPropertyOf transitivity– Domain inference– Range inference
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .@prefix sp: <http://spinrdf.org/sp#> .@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .@prefix owl: <http://www.w3.org/2002/07/owl#> .@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
_:b1 sp:varName "A"^^xsd:string .
[] a sp:Construct ; sp:templates ([ sp:object _:b2 ; sp:predicate rdf:type ; sp:subject _:b3 ]) ; sp:text """PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>CONSTRUCT { ?this a ?B .}WHERE { ?A rdfs:subClassOf ?B . ?this a ?A .}"""^^xsd:string ; sp:where ([ sp:object _:b2 ; sp:predicate rdfs:subClassOf ; sp:subject _:b1 ] [ sp:object _:b1 ; sp:predicate rdf:type ; sp:subject _:b3 ]) .
_:b2 sp:varName "B"^^xsd:string .
_:b3 sp:varName "this"^^xsd:string .
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
CONSTRUCT {?this rdf:type ?B}WHERE { ?A rdfs:subClassOf ?B. ?this rdf:type ?A}
http://www.inria.fr/wimmics/corese/rules/typeprop
Generic HTTP URIs for rules
SPARQL Inferencing Notation (SPIN)http://spinrdf.org/this
A
Brdf:type
rdfs:subClassOf
rdf:type
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• Consuming Linked Justifications– Transforming to human understandable
presentation for explanation– Navigation between related explanation allowing
follow-your-nose principle– Tracing the origins of chains of inferences
(reasoning/truth maintenance)
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Related Work
• Laconic and precise justifications [Horridge et al., 2008]– fine-grained subclasses of justifications (laconic justifications
and precise justifications)– algorithm to compute laconic justifications– our focus is on publishing and consuming distributed
justifications
• Proof Markup Language [McGuinnes et al., 2007]– provenance, information about information manipulation
steps and trust– we have a narrower focus: justifications
•M. Horridge, B. Parsia, and U. Sattler. Laconic and precise justifications in owl. In Proceedings of the 7th International Conference on The Semantic Web, ISWC ’08, pages 323–338, Berlin, Heidelberg, 2008. Springer-Verlag.•D. McGuinness, L. Ding, P. Da Silva, and C. Chang. Pml 2: A modular explanation interlingua. In In AAAI 2007 Workshop on Explanation-aware Computing, 2007.
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• Reasoning, explanation, reason maintenance and semantic wikis [Kotowski and Bry, 2010]– Explanation in incremental development of knowledge
bases– reason maintenance: efficient knowledge base updates– do not discuss representation
• Linked data and provenance in biological data webs [Zhao et al., 2009]– design patterns to encode provenance information
using named graphs•J. Kotowski and F. Bry. A perfect match for reasoning, explanation and reason maintenance: Owl 2 rl and semantic wikis. In Proceedings of 5th Semantic Wiki Workshop, Hersonissos, Crete, Greece (31st May 2010), 2010.•J. Zhao, A. Miles, G. Klyne, and D. Shotton. Linked data and provenance in biological data webs. Briefings in bioinformatics, 10(2):139–152, 2009.
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Provenance, Justification, Explanation
• Justifications: Why someone holds a belief, explanation of why the belief is true, how one knows what one knows. – Wikipedia – Justifications justify why conclusions are drawn.
• Provenance: “sources of information, such as people, entities, and processes, involved in producing, influencing, or delivering a piece of data or a thing in the world”. – W3C Provenance ontology
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Provenance, Justification, Explanation
• Explanation: sets of statements to describe a set of facts in order to clarify the causes, context, and consequences of those facts. – Wikipedia– Main purpose is better understanding through an
objective explanation.
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Future Work
• How other provenance vocabularies can be used together– Combine with provenance vocabularies
• Provide context• Better understanding and trust [McGuinnes et al., 2007]
• W3C Provenance Model– A core data model for provenance– Ratio4TA as a specialization of the W3C PROV Ontology (PROV-O)
• r4ta:Assertion, r4ta:InferredAssertion – prov:Entity• r4ta:Justification – prov:Trace, prov:Account, prov:ProvenanceContainer• r4ta:InferenceRule – prov:Plan• r4ta:inferredByRule – prov:hadPlan, prov:Activity• r4ta:justifies – prov:traceTo, prov:qualifiedTrace• r4ta:antecedent – prov:specializationOf
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• Summarization of justifications
Rules for finding components in the graphs of justification graphs
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• Level of granularity– Single triple– Set of triples• how to deal with overlapped triples in this level
• Efficient storage and query– Huge number of graphs
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Thank Youhttp://ns.inria.fr/ratio4ta/v1/
http://kolflow.univ-nantes.fr/
Ratio4TA
http://wimmics.inria.fr/