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Adding Semantic to Web Data and ServicesPart 3 – From XML to OWL
Doctoral School, St Etienne January 2009
Alain Léger FT R&D Orange Labs ResearchDR Knowledge Processing (KRR)Manager Industry Area IST NoEs OntoWeb et Knowledgeweb (2000 -2007)Associated DR CNRS Lyon I - LIRIS
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Plan Cours 1 (5 janv 09 13:30 – 17:15 / 6 janv 09 8:00 – 11:45)
s Why adding semantics to the Web ? (1h)
QIntroduction
QTake Away and References
s Foundations of Semantic Web (2h45)
QIntroduction to Description Logics
QStandards Inferences and Tableau
s KR languages : from XML, RDF(S) to OWL (2h45)
QXML, RDF, RDF-S
QOWL
s Applications and Roadmap (1h00)
QApplication Scenarios
QVisions prospectives et verrous technologiques
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From traditional to web service interaction …
s XML-based messages Qfor platform-independent machine processing
s Framework focused on extensibilityQfacilitating interoperability
s Machine-processable descriptions Qfacilitating integration
s Loose couplingQmaximizing scalability
IBM's goes on to say that the notion of a web service would have been too inefficient to be interesting a few years ago.
But the trends like cheaper bandwidth and storage, more dynamic content, the pervasiveness and diversity of computing devices with different access platforms
make the need for a glue more important, while at the same time making the costs (bandwidth and storage) less objectionable.
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Fast take up in industry is key !!
s Showing the value to Business UnitsQDo not oversell the technology (AI syndrom …)QConvincing benefits on Not toy scenarios !QFast ROI
s Hiding the complexity of technology to all userss Focusing the research effort on key Industry Roadblockss Making available tools and compliant Frameworkss Sharing the knowledge and theoretical skill with industrys Standardizing on key elements
Do not realize the full picture at once !
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Where we are Today: the Syntactic Web
[Hendler & Miller 02]
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The Syntactic Web is…
sA hypermedia, a digital libraryQA library of documents called (web pages) interconnected by a
hypermedia of linkssA database, an application platformQA common portal to applications accessible through web pages, and
presenting their results as web pagessA platform for multimediaQBBC Radio 4 anywhere in the world! Terminator 3 trailers!
sA naming schemeQUnique identity for those documents
A place where computers do the presentation (easy) and people do the linking and interpreting (hard).
Why not get computers to do more of the hard work?
[Goble 03]
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Hard Work using the Syntactic Web…
Find images of Peter Patel-Schneider, Frank van Harmelen and Alan Rector…
Rev. Alan M. Gates, Associate Rector of the Church of the Holy Spirit, Lake Forest, Illinois
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Impossible (?) using the Syntactic Web…
sComplex queries involving background knowledgeQFind information about “animals that use sonar but are
not either bats or dolphins”sLocating information in data repositoriesQTravel enquiriesQPrices of goods and servicesQResults of human genome experiments
sFinding and using “web services”QVisualise surface interactions between two proteins
sDelegating complex tasks to web “agents”QBook me a holiday next weekend somewhere warm, not
too far away, and where they speak French or English
, e.g., Barn Owl
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Other complex queries ?
s « What are the books written by authors who weremy high school lads? »
s « Who is the person I met at the Aussois school 5 years ago and who was a famous rock climber ? »
s « What are all the video available on Social Europe and broadcasted during summer 95?
s « When occured the first man on the moonwordwide event?
s « Could you suggest an asian restaurant tonightbefore the Italy-Bulgary euro match start?
But not all queries need be complex … in real applications !
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What is the Problem?
sConsider a typical web page:
sMarkup consists of:QRendering information (e.g., font size and
colour)QHyper-links to related content
s Semantic content is accessible to humans but not (easily) to computers…
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What information can we see…
WWW2002The eleventh international world wide web conferenceSheraton waikiki hotelHonolulu, hawaii, USA7-11 may 20021 location 5 days learn interactRegistered participants coming fromaustralia, canada, chile denmark, france, germany, ghana, hong kong, india,
ireland, italy, japan, malta, new zealand, the netherlands, norway, singapore, switzerland, the united kingdom, the united states, vietnam, zaire
Register nowOn the 7th May Honolulu will provide the backdrop of the eleventh
international world wide web conference. This prestigious event …Speakers confirmedTim berners-lee Tim is the well known inventor of the Web, …Ian FosterIan is the pioneer of the Grid, the next generation internet …
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What information can a machine see…
⌧
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Solution: XML markup with “meaningful” tags?
<name> </name>
<location> </location>
<date> </date>
<slogan> </slogan><participants>
</participants>
<introduction>
</introduction>
<speaker> </speaker>
<bio> </bio>…
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Des Formats d’échange (XML)
vers des
Formalismes de Représentation des connaissances (OWL)
Thanks to various people from whom I “borrowed” material : Ian Horrocks et al.
And thanks to all the people from whom they borrowed it ☺
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Panorama
sDemande croissante de
connaissances formalisées
pour le Web: chance IA ?
sLa synthaxe XML fournit
un format 'universel'
stockage et échange pour
KRR distribué sur le Web
DTDs
XML
RDF[S]
Namespaces
Stylesheets
CSSXSLT
XQLQueries
XML-QL
Transformations
Acquisition
Protégé
Ontology
Frames
Rules
XOL
SHOE
HornML
RulesML
DAML+OIL
OWLWeb Services
OWL-SWSDL-S
BPEL4WS
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Semantic Web architecture[A
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“Strings & things”: Unicode + URIs
“The Syntactic Web”: XML + NS + XSD
RDF + RDF Schema
Digital sig
Ontology (vocab)
Logic/proof
Trust
Datalayers
Infolayers
Knowledgelayers
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Need to Add “Semantics”
s External agreement on meaning of annotationsQE.g., Dublin Core
– Agree on the meaning of a set of annotation tagsQProblems with this approach
– Inflexible– Limited number of things can be expressed
s Use Ontologies to specify meaning of annotationsQOntologies provide a vocabulary of termsQNew terms can be formed by combining existing onesQMeaning (semantics) of such terms is formally specifiedQCan also specify relationships between terms in multiple
ontologies
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A Semantic Web — First Steps
sExtend existing rendering markup with semantic markupQMetadata annotations that describe content/funtion of web accessible
resources
sUse Ontologies to provide vocabulary for annotationsQ“Formal specification” is accessible to machines
sA prerequisite is a standard web ontology languageQNeed to agree common syntax before we can share semantics
QSyntactic web based on standards such as HTTP and HTML
Make web resources more accessible to automated processes
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Ontology Languages
sWide variety of languages for “Explicit Specification”QGraphical notations
– Semantic networks– Topic Maps (see http://www.topicmaps.org/)– UML– RDF
QLogic based– Description Logics (e.g., OIL, DAML+OIL, OWL)– Rules (e.g., RuleML, LP/Prolog)– First Order Logic (e.g., KIF)– Conceptual graphs– (Syntactically) higher order logics (e.g., LBase)– Non-classical logics (e.g., Flogic, Non-Mon, modalities)
QProbabilistic/fuzzysDegree of formality varies widelyQ Increased formality makes languages more amenable to
machine processing (e.g., automated reasoning)
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Web “Schema” Languages
s Existing Web languages extended to facilitate content descriptionQXML → XML Schema (XMLS)QRDF → RDF Schema (RDFS)
s XMLS not an ontology languageQChanges format of DTDs (document schemas) to be XMLQAdds an extensible type hierarchy
– Integers, Strings, etc.– Can define sub-types, e.g., positive integers
s RDFS is recognisable as an ontology languageQClasses and propertiesQSub/super-classes (and properties)QRange and domain (of properties)
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Extensible Markup Language (XML)
s Idée-clef:
Q séparer structure et présentation (pas HTML)
sXML DTDs (ou Schéma) definit la structure légale de document
sRemplace HTML avec :
QUn balisage spécifique au domaine
(défini en XML)
QA mappage de ce balisage vers HTML
(défini en XSLT)
sDTD contrôle la correction syntaxiquedes documents échangés
Q1ier niveau de “compréhension”
mutuelle
<employees><employee>
<name>James Smith</name><birthdate>1970-09-30</birthdate><ss_number>555-09-8410</ss_number><position>file clerk</position>
</employee><employee>
<name>Jane Jones</name><birthdate>1968-03-22</birthdate><ss_number>388-71-6662</ss_number><position>marketing manager</position>
</employee><employee><name>Mary Davis</name><birthdate>1972-11-09</birthdate><ss_number>884-99-3192</ss_number><position>lead engineer</position>
</employee></employees>
employees
Name PositionBirthday Ss number
XML : Document = arbre étiqueté
Totally insufficient for adding semantics !
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RDF une structure de données RDFS une terminologie
sRDF (Resource Description Framework)QVers une annotation sémantique plus riche
sRDF a(avait) pour vocation à satisfaire des besoins largesQBibliothéquaires, Qualification de contenus, B2B, B2C, IA, ...
s RDF deux partiesQRDF le Modèle de données (un ensemble de triplets)
QRDF la Syntaxe (XML syntaxe concrète de sérialisation)
sRDFS extends RDF with “schema vocabulary”, e.g.:QClass, Property
Q type, subClassOf, subPropertyOf
Q range, domain
http://www.w3.org/Home/Lassila s:Creator OraLassila
RDF : un graphe orienté
Decidable? Expressiveness ?
For reasoning on semantics?
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RDF - Resource Description Framework
s RDF is a graphical language used for representing
information about resources on the web. It is a
basic ontology language.
s Resources are described in terms of properties
and property values using RDF statements.
s Statements are represented as triples, consisting
of a subject, predicate and object. [S, P, O]
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RDF Example
sSubject: NicksPredicate: hasColleaguesObject: Matthew
[S, P, O]
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Naming Resources In RDF
s RDF uses URIs - Unique Resource Identifiers
to identify resources.
http://www.co-ode.org/people#hasColleague
Co-ode:hasColleague
Actually, to be more precise RDF uses URIRefs to identify resources.
A URIRef consists of a URI and an optional Fragment Identifier separated from the URI by the hash symbol #.
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Vocabularies
sA set of URIRefs is known as a vocabulary
QThe RDF Vocabulary - The set of URIRefs used in descibing
the RDF concepts e.g. rdf:Property, rdf:Resource,
rdf:type.
QThe RDFS Vocabulary - The set of URIRefs used in
describing the RDF Schema langauge e.g. rdfs:Class,
rdfs:domain
QThe ‘Pizza Ontology’ Vocabulary - pz:hasTopping,
pz:Pizza, pz:VegetarianPizza
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Linking Statements
sThe subject of one statement may be the object
of another statement.
sA set of linked statements (triples) forms an
RDF Graph.
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An RDF Graph Example
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RDF Serialisation RDF/XML
<?xml version="1.0"?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"xmlns:coode="http://www.co-ode.org/people#"xml:base="http://www.co-ode.org/people">
<rdf:Description rdf:ID="mh"><coode:hasHomepage rdf:resource="http://www.cs.man.ac.uk/~horridgm"/><coode:hasName>Matthew Horridge</coode:hasName>
</rdf:Description><rdf:Description rdf:ID="nd">
<coode:hasName>Nick Drummond</coode:hasName><coode:hasColleage rdf:resource="#mh"/>
</rdf:Description></rdf:RDF>
<?xml version="1.0"?><rdf:RDF
xmlns:coode="http://www.co-ode.org/people#"xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xml:base="file:/Users/matthewhorridge/Desktop/Test.rdf"><rdf:Description rdf:about="http://www.co-ode.org/people#nd"><coode:hasName>Nick Drummond</coode:hasName><coode:hasColleage><rdf:Description rdf:about="http://www.co-ode.org/people#mh">
<coode:hasName>Matthew Horridge</coode:hasName><coode:hasHomepage rdf:resource="http://www.cs.man.ac.uk/~horridgm"/>
</rdf:Description></coode:hasColleage>
</rdf:Description></rdf:RDF>
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<?xml version="1.0"?><rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"xmlns:xsd="http://www.w3.org/2001/XMLSchema#"xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"xmlns="http://www.owl-ontologies.com/unnamed.owl#"
xml:base="http://www.owl-ontologies.com/unnamed.rdf"><rdfs:Class rdf:ID="Person"/><rdf:Property rdf:ID="hasFather"/><Person rdf:ID="Matthew">
<hasFather><Person rdf:ID="Peter"/>
</hasFather></Person>
</rdf:RDF>
sIsaViz RDF Editor
sProtege-OWL in RDF(S) mode
Editing RDF(S)
<?xml version="1.0"?><rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"xmlns:xsd="http://www.w3.org/2001/XMLSchema#"xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"xmlns="http://www.owl-ontologies.com/unnamed.owl#"
xml:base="http://www.owl-ontologies.com/unnamed.rdf"><rdfs:Class rdf:ID="Person"/><rdf:Property rdf:ID="hasFather"/><Person rdf:ID="Matthew">
<hasFather><Person rdf:ID="Peter"/>
</hasFather></Person>
</rdf:RDF>
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RDF Schema (RDFS)
s RDF gives a formalism for meta data annotation, and a way to write it down in XML, but it does not give any special meaning to vocabulary such as subClassOf or typeQInterpretation is an arbitrary binary relation
s RDF Schema allows you to define vocabulary terms and the relations between those termsQit gives “extra meaning” to particular RDF predicates and resourcesQthis “extra meaning”, or semantics, specifies how a term should be interpreted
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RDFS Examples
s RDF Schema terms (just a few examples):QClassQPropertyQtypeQsubClassOfQrangeQdomain
s These terms are the RDF Schema building blocks (constructors) used to create vocabularies:
<Person,type,Class><hasColleague,type,Property><Professor,subClassOf,Person><Carole,type,Professor><hasColleague,range,Person><hasColleague,domain,Person>
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RDF/RDFS “Liberality”
s No distinction between classes and instances (individuals)<Species,type,Class><Lion,type,Species><Leo,type,Lion>
s Properties can themselves have properties<hasDaughter,subPropertyOf,hasChild><hasDaughter,type,familyProperty>
s No distinction between language constructors and ontology vocabulary, so constructors can be applied to themselves/each other<type,range,Class><Property,type,Class><type,subPropertyOf,subClassOf>
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Semantics and Model Theories
s Ontology/KR languages aim to model (part of) worlds Terms in language correspond to entities in worlds Meaning given by, e.g.:
QMapping to another formalism, such as FOL, with own well definedsemanticsQor a bespoke Model Theory (MT)
s MT defines relationship between syntax and interpretationsQCan be many interpretations (models) of one piece of syntaxQModels supposed to be analogue of (part of) world
– E.g., elements of model correspond to objects in worldQFormal relationship between syntax and models
– Structure of models reflect relationships specified in syntaxQInference (e.g., subsumption) defined in terms of MT
– E.g., T ² A \sqsubseteq B iff in every model of T, ext(A) \subseteq ext(B)
RDF/RDFS Semantics
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s RDF has “Non-standard” semantics in order to deal with thiss Semantics given by RDF Model Theory (MT)
s In RDF MT, an interpretation I of a vocabulary V consists of:
QIR, a non-empty set of resources
QIS, a mapping from V into IR
QIP, a distinguished subset of IR (the properties)– A vocabulary element v ∈ V is a property iff IS(v) ∈ IP
QIEXT, a mapping from IP into the powerset of IR×IR
– I.e., a set of elements <x,y>, with x,y elements of IR
QIL, a mapping from typed literals into IR
s Class interpretation ICEXT simply induced byIEXT(IS(type))– ICEXT(C) = {x | <x,C> ∈ IEXT(IS(type))}
RDF/RDFS Semantics
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Example RDF/RDFS Interpretation
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RDFS Interpretations
s RDFS adds extra constraints on interpretationsQE.g., interpretationss of <C,subClassOf,D> constrained to those where ICEXT(IS(C)) ⊆ ICEXT(IS(D))
s Can deal with triples such asQ<Species,type,Class> <Lion,type,Species> <Leo,type,Lion>Q<SelfInst,type,SelfInst>
s And even with triples such asQ<type,subPropertyOf,subClassOf>
s But not clear if meaning matches intuition (if there is one)
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Problems with RDFS
s RDFS too weak to describe resources in sufficient detailQNo localised range and domain constraints
– Can’t say that the range of hasChild is person when applied to persons and elephant when applied to elephants
QNo existence/cardinality constraints– Can’t say that all instances of person have a mother that is also a person, or that persons have exactly 2 parents
QNo transitive, inverse or symmetrical properties– Can’t say that isPartOf is a transitive property, that hasPart is the inverse of isPartOf or that touches is symmetrical
Q…
s Difficult to provide reasoning supportQNo “native” reasoners for non-standard semanticsQMay be possible to reason via FO axiomatisation
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Where To go: Knowledge Representation Requirements !!
q Good syntaxRead Ontological contents
q Good SemanticProcess Ontological content
q The right expressiveness just neededRepresent adequately the domain
q Support of inference mecanismsMany possible reasoning services
q A good trade-off expressiveness/complexityMapping/fusion of ontologies
Inference with “good properties” (completeness, correctness, polynomial tractability, etc.)
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OWL Class Constructors and Axioms
s XMLS datatypes as well as classes in ∀P.C and ∃P.CQ E.g., ∃hasAge.nonNegativeInteger
s Arbitrarily complex nesting of constructorsQ E.g., Person u ∀hasChild.Doctor t ∃hasChild.Doctor
s Axioms (mostly) reducible to inclusion (v)Q C ≡ D iff both C vD and D v C
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OWL Class Constructors
s XMLS datatypes as well as classes in ∀P.C and ∃P.CQE.g., ∃hasAge.nonNegativeInteger (see work by Zhiming Pan)
QRestricted form of DL concrete domains Arbitrarily complex nesting of constructors
QE.g., Person u ∀hasChild.Doctor t ∃hasChild.Doctor
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OWL Axioms
s Axioms (mostly) reducible to inclusion (v)QC ≡ D iff both C v D and D v C
s Obvious FOL equivalencesQE.g., C ≡ D ⇔ ∀x.C(x)↔ D(x), C v D ⇔ ∀x.C(x)→D(x)
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RDFS Syntax
<owl:Class><owl:intersectionOf rdf:parseType=" collection"><owl:Class rdf:about="#Person"/><owl:Restriction><owl:onProperty rdf:resource="#hasChild"/><owl:toClass><owl:unionOf rdf:parseType=" collection"><owl:Class rdf:about="#Doctor"/><owl:Restriction><owl:onProperty rdf:resource="#hasChild"/><owl:hasClass rdf:resource="#Doctor"/>
</owl:Restriction></owl:unionOf>
</owl:toClass></owl:Restriction>
</owl:intersectionOf></owl:Class>
E.g., Person u ∀hasChild.(Doctor t ∃hasChild.Doctor):
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Ontology / Tbox Axioms
s Obvious FOL/Modal Logic equivalencesQE.g., DL: C v D FOL: ∀x.C(x)→D(x) ML: C→D
s Often distinguish two kinds of Tbox axiomsQ“Definitions” C v D or C ≡ D where C is a concept name
QGeneral Concept Inclusion axioms (GCIs) where C may be complex
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Ontology Facts / Abox Axioms
s Note: using nominals (e.g., in SHOIN), can reduce Aboxaxioms to concept inclusion axioms
Q equivalent to QQ equivalent to
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DL Knowledge Bases (Ontologies)
sAn OWL ontology maps to a DL Knowledge Base K = hT ,AiQT (Tbox) is a set of axioms of the form:
– C v D (concept inclusion)– C ≡ D (concept equivalence)– R v S (role inclusion)– R ≡ S (role equivalence)– R+ v R (role transitivity)
QA (Abox) is a set of axioms of the form – x ∈ D (concept instantiation)– hx,yi ∈ R (role instantiation)
sTwo sorts of Tbox axioms often distinguishedQ“Definitions”
– C v D or C ≡ D where C is a concept name
QGeneral Concept Inclusion axioms (GCIs)– C v D where C in an arbitrary concept
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Knowledge Base Semantics
sAn interpretation I satisfies (models) an axiom A (I ² A):
QI ² C v D iff CI ⊆ DI
QI ² C ≡ D iff CI = DI
QI ² R v S iff RI ⊆ SI
QI ² R ≡ S iff RI = SI
QI ² R+ v R iff (RI)+ ⊆ RI
QI ² x ∈ D iff xI ∈ DI
QI ² hx,yi ∈ R iff (xI,yI) ∈ RI
sI satisfies a Tbox T (I ² T ) iff I satisfies every axiom A in TsI satisfies an Abox A (I ² A) iff I satisfies every axiom A in AsI satisfies an KB K (I ² K) iff I satisfies both T and A
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OWL species
s RDF & RDFS do not provide a mechanism for specifying restrictions
s Lite: class hierarchies, simple restrictions
s DL: all inferences can be computed and will finish in finite time
s Full: classes can be treated both as classes and as individuals
Lite
DL
Full
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Class and sub-class
<rdf:RDFxmlns:rdf= "http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#”xmlns:owl="http://www.w3.org/2002/07/owl#">xml:base= "http://www.animals.fake/animals#">
<owl:Class rdf:ID="animal" />
<owl:Class rdf:ID="horse"><rdfs:subClassOf rdf:resource="#animal"/>
</owl:Class></rdf:RDF>
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Example RDFs - OWL
<Ontology xmlns:rdf= "http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#”xmlns:owl="http://www.w3.org/2002/07/owl#">xml:base= "http://www.animals.fake/animals#">
<Declaration><OWLClass URI="&animals;animal"/>
</Declaration>
<SubClassOf><OWLClass URI="&animals;horse"/><OWLClass URI="&animals;animal"/>
</SubClassOf>
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RDFs – OWL Example
<owl:Class rdf:about="#Pizza"><rdfs:label>Pizza</rdfs:label><rdfs:subClassOf rdf:resource="#Food"/><rdfs:subClassOf>
<owl:Restriction><owl:onProperty rdf:resource="#hasBase"/><owl:someValuesFrom rdf:resource="#PizzaBase"/>
</owl:Restriction></rdfs:subClassOf><owl:disjointWith rdf:resource="#PizzaBase"/><owl:disjointWith rdf:resource="#PizzaTopping"/>
</owl:Class>
Every pizza has at least one base (hasBasePizzaBase)
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RDFS – OWL Example
<owl:ObjectProperty rdf:about="#hasTopping"><rdfs:domain rdf:resource="#Pizza"/><rdfs:range rdf:resource="#PizzaTopping"/><rdfs:subPropertyOf rdf:resource="#hasIngredient"/><owl:inverseOf rdf:resource="#isToppingOf"/>
</owl:ObjectProperty>
<owl:DatatypeProperty rdf:about="#diameter"><rdf:type rdf:resource="&owl;FunctionalProperty"/><rdfs:domain rdf:resource="#PizzaBase"/><rdfs:range rdf:resource="&xsd;nonNegativeInteger"/>
</owl:DatatypeProperty>
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RDFs – OWL example
<owl:Class rdf:about="#Pizza"><rdfs:label>Pizza</rdfs:label><rdfs:subClassOf rdf:resource="#Food"/><owl:disjointWith rdf:resource="#PizzaBase"/><owl:disjointWith rdf:resource="#PizzaTopping"/>
</owl:Class>
<owl:Class rdf:about="#PizzaBase"><rdfs:label>BaseDaPizza</rdfs:label><rdfs:subClassOf rdf:resource="#Food"/>
</owl:Class>
<owl:Class rdf:about="#PizzaTopping"><rdfs:subClassOf rdf:resource="#Food"/>
</owl:Class>
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Use a (Description) Logic
s OWL DL based on SHIQ Description LogicQIn fact it is equivalent to SHOIN(Dn) DL
s OWL DL Benefits from many years of DL researchQWell defined semantics
QFormal properties well understood (complexity, decidability)
QKnown reasoning algorithms
QImplemented systems (highly optimised)
s In fact there are three “species” of OWL (!)QOWL full is union of OWL syntax and RDFQOWL DL restricted to First Order fragment (≈ DAML+OIL)
QOWL Lite is “simpler” subset of OWL DL (equiv to SHIF(Dn))
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Remerciements
s Une pensée toute particulière à tous ceux à qui j'ai emprunté, et ils sont nombreux !
s Et à ceux qui m'ont emprunté …☺
Merci !
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Lectures conseillées
A Semantic Web Primer, Grigoris Antoniou and Frank Van Harmelen, MIT Press, April 2004, 258 pp., ISBN-10: 0-262-01210-3, ISBN-13: 978-0-262-01210-2
XML tutorial
http://www.w3schools.com/xml/default.asp
RDF tutorial
http://www.w3schools.com/rdf/default.asp
OWL guide
http://www.w3.org/TR/owl-guide/
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Annex Complement on RDF
From Joerg Diederich, knowledge Web Education Ressources REASE
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RDF Complement
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RDF Complement
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RDF Complement (basic building blocks)
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RDF Complement
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RDF Complement (basic building blocks)
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RDF Complement (basic building blocks)
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RDF Complement (basic building blocks)
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RDF Complement (xml serialization)
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RDF Complement (xml serialization)
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RDF Complement (data types in RDF)
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RDF Complement (Reification)
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RDF Complement (discussion and critics)
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RDF Complement (discussion and critics)
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RDF Complement (container elements)
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RDF Complement (container elements)
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RDF Complement (container elements)
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RDF Complement (container elements)
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RDF Complement (container elements)
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RDF Complement (container elements)
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RDF Complement (container elements)
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RDFS Complement (motivation)
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RDFS Complement (subclass hierarchy)
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RDFS Complement (subclass hierarchy)
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RDFS Complement (subclass hierarchy)
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RDFS Complement (Domain and Range)
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RDFS Complement (Domain and Range)
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RDFS Complement (Domain and Range)
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RDFS Complement (example)
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RDFS Complement (example)