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Knowledge Standards W3C Semantic Web. Olivier.Corby@sophia.inria.fr. PLAN. W3C Semantic Web Standards Two layers : XML/RDF Syntax/Semantics XML : DTD, XML Schema, XSLT, XPATH, XQUERY RDF : RDFS, OWL, RIF, SPARQL. XML. Meta language : conventions to define languages
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Knowledge StandardsW3C Semantic Web Olivier.Corby@sophia.inria.fr
PLAN W3C Semantic Web Standards • Two layers : XML/RDF Syntax/Semantics • XML : DTD, XML Schema, XSLT, XPATH, XQUERY • RDF : RDFS, OWL, RIF, SPARQL
XML • Meta language : conventions to define languages • Abstract syntax tree language • STANDARD • Every XML parser in any language (Java, C, …) can read any XML document • Data/information/knowledge outside the application • A family of languages and tools
XML Family • DTD : grammar for document structure • XML Schema & datatypes • XPath : path language to navigate XML documents • XSLT : Extensible Stylesheet Language Transformation : transforming XML documents into XML (XHTML/SVG/text) documents
XSLT • Define output presentation formats OUTSIDE the application • Everybody can customize/adapt outpout format for specific application/user/task • Can deliver an application with some generic stylesheets that can be adapted • Application generates XML as query result format processed by XSLT • The XML output format can be interpreted as dynamic object by navigator : e.g. a FORM
XQuery • XML Query Language • AKO programming language • SQL 4 XML
Semantic Web "The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation." Tim Berners-Lee, James Hendler, Ora Lassila,The Semantic Web, Scientific American, May 2001 • Information Retrieval & Knowledge Representation • W3C Standards (RDF/S, SPARQL, OWL)
Noise Precision Missed Recall Agences I’RAM La Galère 148, rue Victor Hugo 76600 Le Havre L’Agence de la Presse et des Livres 38, rue Saint Dizier BP 445 54001 Nancy Cédex RESUME DU ROMAN DE VICTOR HUGO NOTRE DAME DE PARIS(1831) - 5 parties L'enlèvement . Livres 1-2 : 6 janvier 1482. L'effrayant bossu Quasimodo Example of problem…
The Man Who Mistook His Wife for a Hat : And Other Clinical Tales by W. In his most extraordinary book, "one of the great clinical writers of the 20th century" (The New York Times) recounts the case histories of patients lost in the bizarre, apparently inescapable world of neurological disorders. Oliver Sacks's The Man Who Mistook His Wife for a Hat tells the stories of individuals afflicted with fantastic perceptual and intellectual aberrations: patients who have lost their memories and with them the greater part of their pasts; who are no longer able to recognize people and common objects; who are stricken with violent tics and grimaces or who shout involuntary obscenities; whose limbs have become alien; who have been dismissed as retarded yet are gifted with uncanny artistic or mathematical talents. If inconceivably strange, these brilliant tales remain, in Dr. Sacks's splendid and sympathetic telling, deeply human. They are studies of life struggling against incredible adversity, and they enable us to enter the world of the neurologically impaired, to imagine with our hearts what it must be to live and feel as they do. A great healer, Sacks never loses sight of medicine's ultimate responsibility: "the suffering, afflicted, fighting human subject." Our rating : Find other books in : Neurology Psychology Search books by terms : Web for humans … Oliver Sacks Oliver Sacks
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How are we doing ? • Last document you have read ? • Answer based on concept structuring : • objects / categories & identification • Category hierarchy : abstraction structure specialisation / generalisation • Answer based on consensus (sender, public, receiver) • Structure and consensus is called : ‘ontology’ • Description of what exist and of categories exploitedin software solutions • In computer science, an ontology is an object not a discipline like in philosophy
Ontology ontos being logos discourse onto logy Study general properties of existing things representationof these properties in formalism that support rational processing
Informal Document Subsumption Book Formal Binary transitive Relation Novel Essay Ontology & subsumption • Knowledge identification • Document types acquisition • Model & formalise representation “Novel and Essay are books" “A book is a document."
Document Title String 1 2 Ontology & binary relation • Knowledge identification • Document Types acquisition • Model & formalise representation “A document has a title. A title is a string" Informal Formal
Living Being Document Human Book Man Woman Novel Essay Document Title String 1 2 Document Author Human 1 2 Human Name String 1 2 NAME AUTHOR TITLE Author1 Name1 Title1 "Hugo" Man1 Nov1 "Notre Dame de Paris" STRING MAN NOVEL STRING Ontologie & annotation Hugo isauthor ofNotre Dame de Paris
Document Book Novel Essay NAME AUTHOR TITLE ? "Hugo" STRING MAN DOCUMENT STRING NAME AUTHOR TITLE Author1 Nam1 Title1 "Hugo" Hom1 Rom1 "Notre Dame de Paris" STRING MAN NOVEL STRING Annotation, Query & Projection • Search : Query • Projection Inference • Precision & Recall
Living Being Document Human Book Man Woman Novel Essay Document Title String 1 2 Document Author Human 1 2 Human Name String 1 2 NAME AUTHOR TITLE Author1 Nam1 Title1 "Hugo" Hom1 Rom1 "Notre Dame de Paris" STRING MAN NOVEL STRING Hugo est l'auteur de Notre Dame de Paris Ontology & annotation
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book novel book novel Formal Languages • First order Logic(x) (Roman(x) Livre(x)) • Conceptual Graphs Roman < Livre • Object Languages public class Roman extends Livre • Description LogicsRoman (and Livre (not Essai)) • Semantic Web RDFS & OWL<rdfs:Class rdf:ID=“Novel"> <rdfs:label xml:lang="en">novel</rdfs:label> <rdfs:label xml:lang="fr">roman</rdfs:label> <rdfs:subClassOf rdf:resource="#Book"/></rdfs:Class>
< >… </ > Abstract: (1) Web for machines • Information Integration at the scale of Web • Actual Web : natural language for humans • Semantic Web : same + formal language for machines; Evolution,not revolution • Metadata = dateaboutdata i.e. above actualweb • Goal: interoperability, automatisation, reuse
Abstract: (2) standardise • Languages, models and formats forexchange… • Structure andnaming: XML, Namespaces, URINovel -> http://www.palette.eu/ontology#Novel • Models &ontologies: RDF/S & OWLpal:Novel(x) pal:Book(x) • Protocols &queries: HTTP, SOAP, SPARQL • Next: rules, web services, semantic web services, security, trust. • Explicitwhatalready exists implicitely: • Capture, ex: ressource types, author, date • Publish ex: format structures ex: jpg/mpg, doc/xsl
Abstract: (3) open& share • Shared understanding of information • Between humans • Between applications • Between humans and applications • In « Semantic Web» Web lies in URI http://www.essi.fr , ftp://ftp.ouvaton.org , mailto:fgandon@inria , tel:+33492387788 , http://www.palette.eu/ontology#Novel, etc.
<accident> <date> 19 Mai 2000 </date> <description> <facteur>le facteur </description> </accident> Ontologies Documents XML Legacy Users <ns:article rdf:about="http://intranet/articles/ecai.doc"> <ns:title>MAS and Corporate Semantic Web</ns:title> <ns:author> <ns:person rdf:about="http://intranet/employee/id109" /> </ns:author> </ns:article> <rdfs:Class rdf:ID="thing"/> <rdfs:Class rdf:ID="person"> <rdfs:subClassOf rdf:resource="#thing"/> </rdfs:Class> queries answers suggestion RDF Schema RDF Metadata, instances of RDFS RDFS RDF SPARQL Rules XML Semantic Web Server CG Support Web Stack QUERIES PROJECTION RULES CG Base CORESE ONTOLOGY CG Result RDFS CG Rules INFERENCES RDF XML NAMESPACES CG Queries URI UNICODE Semantic Search Engine
RDF Resource Description Framework W3C language for the Semantic Web Representing resources in the Web Triple model : resource property value RDF/XML Syntax RDF Schema : RDF Vocabulary Description Language
Ontology (concepts / classes) class Document class Report subClassOf Document class Topic class ComputerScience subClassOf Topic Document Report Memo Topic ComputerScience Maths
Ontology (relations / properties) property authordomain Documentrange Person property concerndomain Documentrange Topic Person Document author Topic Document concern
Ontologie RDFS / XML <rdfs:Class rdf:ID=‘Document’/> <rdfs:class rdf:ID=‘Report’> <rdfs:subClassOf rdf:resource=‘#Document’/> </rdfs:Class> <rdf:Property rdf:ID=‘author’> <rdfs:domain rdf:resource=‘#Document’/> <rdfs:range rdf:resource=‘#Person’/> </rdf:Property>
OntologyOWL Transitive Symmetric InverseOf
Metadata Report RR-1834 written by Researcher Olivier Corby, concern Java Programming Language Report http://www.inria.fr/RR-1834.html author http://www.inria.fr/o.corby concern http://www.inria.fr/acacia#Java Researcher http://www.inria.fr/o.corby name “Olivier Corby” Report http://www.inria.fr/RR-1834.html Researcher http://www.inria.fr/o.corby author Olivier Corby name Java http://www.inria.fr/acacia#Java concern
Query : SPARQL Using Ontology Vocabulary Find documents about Java select ?doc where ?doc rdf:type c:Document ?doc c:concern ?topic ?topic rdf:type c:Java Document ?doc Java ?topic concern
Ontology based queries • Reports, articles are documents, … • Documents have authors, which are persons • People have center of interest Document Report Article Memo Person Document author Topic Person interest
SPARQL Query Language select variable where { exp } Exp : resource property value ?x rdf:type c:Person ?x c:name ?name filter ?name = “Olivier”
Query Example select ?x ?name where { ?x c:name ?name ?x c:member ?org ?org rdf:type c:Consortium ?org c:name ?n filter regex(?n, ‘palette’) }
Statements triple graph pattern PAT union PAT PAT option PAT graph ?src PAT filter exp XML Schema datatypes
Statements distinct order by limit offset
Group Group documents by author select * group ?person where ?doc rdf:type ex:Document ?doc ex:author ?person ?doc ex:date ?date person date doc (1) John 1990 2000 D1 D3 (2) Jack 2000 D2 D4
Group Group documents by author and date select * group ?person group ?date where ?doc rdf:type ex:Document ?doc ex:author ?person ?doc ex:date ?date person date doc (1) John 1990 D1 (2) John 2004 D3 (3) Jack 2000 D2 D4
Count Count the documents of authors select * group ?person count ?doc where ?doc ex:author ?person person doc count John D1 D3 2 Jack D2 D4 2
Approximatesearch • Find best approximation (of types) according to ontology • Example: • Query TechnicalReportabout Java written by an engineer? • Approximate answer : TechnicalReport CourseSlide EngineerTeam
Distance in ontology Objet Document Acteur Personne Équipe Rapport Cours Ingénieur Chercheur R. Recherche R. Technique Support C.
Distance in ontology Objet 1 Document Acteur 1/2 Personne Équipe Rapport Cours 1/4 Ingénieur Chercheur R. Recherche R. Technique Support C.
Distances • Semantic distance • Distance = sum of path length between approximate concepts • Minimize distance, sort resultsby distance and apply threshold • Syntax: select more where exp
Inferences & Rules Exploit inferences (rules) for information retrieval If amemberof a team has a center of interestthenthe team shares this center of interest ?person interestedBy ?topic ?person member ?team ?team interestedBy ?topic Person ?person Topic ?topic interestedBy interestedBy Team ?team member
Inferences & Rules : Classifya resource IF a person has written PhD Thesis on a subject THEN she is a Doctor and is expert on the subject ?person author ?doc ?doc rdf:type PhDThesis ?doc concern ?topic ?person expertIn ?topic ?person rdf:type PhD PhDThesis ?doc Person ?person author Topic ?topic concern PhD ?person expertIn
Graph Rules Conceptual Graph rules Rule holds if there is a projection of the condition on the target graph Apply conclusion by joining the conclusion graph to the target graph Forward chaining engine
RDF/XML Syntax <cos:rule> <cos:if>?person author ?doc?doc rdf:type PhDThesis?doc concern ?topic </cos:if> <cos:then>?person expertIn ?topic?person rdf:type PhD </cos:then> </cos:rule>
Example : symmetry <cos:rule> <cos:if> ?x c:related ?y </cos:if> <cos:then> ?y c:related ?x </cos:then> </cos:rule>
Example : symmetry <cos:rule> <cos:if> ?p rdf:type owl:SymmetricProperty ?x ?p ?y </cos:if> <cos:then> ?y ?p ?x </cos:then> </cos:rule>
Example : transitivity <cos:rule> <cos:if> ?x c:partOf ?y ?y c:partOf ?z </cos:if> <cos:then> ?x c:partOf ?z </cos:then> </cos:rule>
Example : transitivity <cos:rule> <cos:if> ?p rdf:type owl:TransitiveProperty ?x ?p ?y ?y ?p ?z </cos:if> <cos:then> ?x ?p ?z </cos:then> </cos:rule>