Adding Semantic to Web Data and Servicesbeaune/websem/cours2008_2009/... · Adding Semantic to Web Data and Services Part 3 – From XML to OWL Doctoral School, ... presenting their

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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

France Télécom R&D Diffusion of this document is subject to the autorisation of France Télécom R&DD2 - 09/01/2009

Cours Web Services sémantiques © Alain Léger FT R&D, ENS M SE St Etienne, 3 january 2006

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



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.



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 !



Where we are Today: the Syntactic Web

[Hendler & Miller 02]



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]



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



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



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 !



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…



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 …



What information can a machine see…

⌧



Solution: XML markup with “meaningful” tags?

<name> </name>

<location> </location>

<date> </date>

<slogan> </slogan><participants>

</participants>

<introduction>

</introduction>

<speaker> </speaker>

<bio> </bio>…



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 ☺



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



Semantic Web architecture[A

dapt

ed fr

om S

eman

tic W

eb "l

ayer

cak

e" s

lide

due

to T

im B

erne

rs-L

ee]

“Strings & things”: Unicode + URIs

“The Syntactic Web”: XML + NS + XSD

RDF + RDF Schema

Digital sig

Ontology (vocab)

Logic/proof

Trust

Datalayers

Infolayers

Knowledgelayers



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



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



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)



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)



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 !



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?



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]



RDF Example

sSubject: NicksPredicate: hasColleaguesObject: Matthew

[S, P, O]



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 #.



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



Linking Statements

sThe subject of one statement may be the object

of another statement.

sA set of linked statements (triples) forms an

RDF Graph.



An RDF Graph Example



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>




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)


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>



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



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>



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>



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



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



Example RDF/RDFS Interpretation



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)



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



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.)



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



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



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)



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):



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



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



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



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



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



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>



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>



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)



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>



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>



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))



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 !



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/



Annex Complement on RDF

From Joerg Diederich, knowledge Web Education Ressources REASE



RDF Complement



RDF Complement



RDF Complement (basic building blocks)



RDF Complement












RDF Complement (xml serialization)



RDF Complement (xml serialization)



RDF Complement (data types in RDF)



RDF Complement (Reification)



RDF Complement (discussion and critics)



RDF Complement (discussion and critics)



RDF Complement (container elements)





















RDFS Complement (motivation)



RDFS Complement (subclass hierarchy)









RDFS Complement (Domain and Range)









RDFS Complement (example)



RDFS Complement (example)

Documents

Adding Semantic to Web Data and Servicesbeaune/websem/cours2008_2009/... · Adding Semantic to Web Data and Services Part 3 – From XML to OWL Doctoral School, ... presenting their