web05 semantic web: rdf schema

Dr. Sabin Buraga http://www.purl.org/net/busaco

Semantic Web <?xml version=“1.0” ?><curs desc=“…” />

Web semantic

Dr. SabinCorneliu BuragaFacultatea de Informatica

Universitatea “A.I.Cuza” – Iasi, Romania

http://www.infoiasi.ro/~busaco/

Realizarea inferentelor via RDF(S)

“Toate erau laolalta – dupa aceea a venit minteasi le‐a pus in ordine.”

Anaxagoras

constatare

Declaratiile RDF se situeaza la nivel de instante (indivizi)

constatare

Lipseste un mecanism de declarare a unui vocabular

constatare

<rdf:Description rdf:about="http://www.apple.com/macbook"> <s:Produs>MacBook</s:Produs>

</rdf:Description>

In loc de produs putem folosi laptop orimarfa?Conceptul produs este definit in relatie cu altele?

Resursa descrisa poate fi modelata diferit?Ce proprietati sunt asociate unui produs?

necesitati

Un mecanism de specificarea unui model de cunostinte privitor la un web

specificarea unei taxonomii a resurselor

necesitati

O modalitate de a specificarelatiile dintre (clase de) resurse

RDF este un model care permite specificarea de relatiiintre doua obiecte

necesitati

Ne‐ar fi util un model ce permite definireaunei taxonomii, in termeni de clase, superclase

si subclase de resurse

taxonomii

Taxonomia reprezintă studiul principiilorgenerale de clasificare ştiințifică,

i.e. clasificarea sistematică

detalii in (Daum et al., 2003)

taxonomii

Resursele pot fi clasificate sub forma unei ierarhii,conform unor relații în prealabil fixate stabilite

între entitățile pe care le reprezintă în lumea reală

taxonomii

Taxonomie ≡ arbore:

noduri – concepte (clase)

relații dintre noduri – relații de sub‐/supra‐clasificare (generalizare/specializare)

taxonomii

Fiecare nod (entitate) posedao proprietate specifica, proprietate caracteristica

sub‐clasei din care face parte

taxonomii: exemplu

Conform (Alan Rector et al., 2004)

taxonomii: exemplu

Conform (Christian Ricci, 2004)

Bernstein et al., 2005

taxonomii: utilizari

Clasificarea resurselor

model simplu de clasificare

taxonomie = ontologie simpla

exemplu mentionat de (Bouquet, Serafini & Zanobini, 2005)

Structuri de directoare de fisiere

Categorii de situri Web – cataloage, directoriesOpen Directory: dmoz.org

Comert electronicUniversal Standard Products and Services Classification:

www.eccma.org

Clasificarea serviciilor Webse realizeaza via tModel,

folosindu‐se North American Industry Classification System

taxonomii: model

Modelarea poate fi realizata via scheme RDF

rdf schema

Permite definirea de taxonomii

în termeni de clase, super‐clase şi sub‐clase de resurse

(Brickley & Guha, 2004)

rdf schema

Recomandare a Consortiului Web

www.w3.org/TR/rdfschema/

rdf schema

Ofera o modalitate de specificarea unui vocabular de termeni side relatii intre acesti termeni

precizeaza contructiile – conceptele – ce pot fi utilizateintr‐un domeniu dat

poate descrie relatiile dintre elementele de vocabularapartinind unor vocabulare diferite

rdf schema

Adauga semantica predicatelor si resurselor RDF

poate defini maniera in care un termen trebuie interpretat, specificindu‐i proprietatile sale si stabilind ce tipuri

de “lucruri” pot fi valorile acestor proprietati

Contine definitii si restrictii de utilizarea proprietatilor

Fiecare predicat e identificat printr‐o schema unica

Pune la dispozitie maniere de specificarea claselor si proprietatilor obiectelorin contextul utilizarii unui vocabular

rdf schema

Clasa (Class) & proprietatea (Property)

Persoana, type, ClassareIdentitate, type, Property

Aplicatie, type, ClassruleazaPe, type, Property

rdf schema: terminologie

Tip (type), sub‐clasa (subClassOf), domeniu (domain), interval (range)

Autor, subClassOf, PersoanaCompanie, subClassOf, Producator

esteStudent, domain, PersoanaesteStudent, range, xsd:Boolean

areNume, range, xsd:String

O schema RDF fiind exprimata prin triple RDF,pot fi efectuate interogari SPARQL:

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>SELECT ?clasaWHERE {

?clasa rdf:type rdfs:Class} ORDER BY ?clasa

Clase fundamentale:rdfs:Resource – clasa resurselor

rdf:Property – clasa proprietatilor resurselor

rdfs:Class – corespunde conceptului de tip sau categorie

rdfs:Container – clasa generica privindcontainerele de date RDF

rdfs:Datatypes – clasa tipurilor de date

rdf schema: model

Clasele specifica resurse Web (identificate de URI):pagini

tipuri de documentebaze de datepersoane…

rdf schema: model

Resursele apartinind unei clase = instante

clase specificate via RDF Schemainstantele sunt exprimate prin RDF

rdf schema: model

Proprietati fundamentale:

rdf:type – indica faptul ca o resursaeste membra a unei clase

rdfs:subClassOf – relatia de mostenirea claselor (tranzitiva)

rdfs:subPropertyOf – relatia de mostenire a proprietatilor

rdf schema: model

Clasa Multimedia include subclasele Audio si Video<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"

xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"> <rdf:Description rdf:ID="Multimedia">

<rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class" />

</rdf:Description><rdf:Description rdf:ID="Video">

<rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class" />

<rdfs:subClassOf rdf:resource="#Multimedia" /> </rdf:Description>

rdf schema: exemplu

Clasa Multimedia include subclasele Audio si Video(continuare)

<rdf:Description rdf:ID="Audio"> <rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class" />

<rdfs:subClassOf rdf:resource="#Multimedia" /> </rdf:Description>

</rdf:RDF>

rdf schema: exemplu

Restrictii:impuse asupra claselor si/sau proprietatilor

rdfs:range – restrictioneaza valorile unei proprietati

rdfs:domain – specifica o clasa care poate fi asignataca valoare a unei proprietati

rdf schema: model

Clasei Multimedia ii asociem proprietatea durationcu valori din multimea numerelor intregi

<rdfs:Property rdf:ID="duration"> <rdfs:domain rdf:resource="#Multimedia" /> <rdfs:range rdf:resource="#Integer" />

</rdf:Description>

rdf schema: exemplu

Remarca:nu e obligatoriu sa definim conceptul Integer

ipoteza lumilor deschisecontrast cu modelul bazelor de date clasice

rdf schema: model

rdf schema: exemplu

Parte de vorbire

Substantiv Verb

Verb reflexivSubst. comunSubiectAl

sub-class of sub-class of

sub-class of sub-class ofdomain

Nivelul ontologicNivelul datelor

SubiectAlCrocodilii se joaca

type type

rdf schema: exemplu (Ide, 2003)

domain range

subClassOf subClassOf

subClassOf

Definirea claselor:<rdfs:Class rdf:about=

"http://www.linguistics.org/schema.rdf#PartOfSpeech"><rdfs:label>POS</rdfs:label> <rdfs:comment xml:lang="ro">Clasa desemnind categoria generala

“parte de vorbire”</rdfs:comment></rdfs:Class>

<rdfs:Class rdf:about="http://www.linguistics.org/schema.rdf#Noun"><rdfs:label>Noun</rdfs:label> <rdfs:comment xml:lang="ro">Clasa substantivelor</rdfs:comment> <rdfs:subClassOf rdfs:resource=

"http://www.linguistics.org/schema.rdf#PartOfSpeech"/></rdfs:Class>

rdf schema: exemplu

Definirea proprietatilor:

<rdfs:Property rdf:about="http://www.linguistics.org/schema.rdf#number">

<rdfs:domain rdf:resource="http://www.linguistics.org/schema.rdf#PartOfSpeech" />

<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal" />

</rdfs:Property>

rdf schema: exemplu

Folosirea – la nivel de instante – a schemei RDF specificate:<rdf:RDFxmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"

xmlns:pos="http://www.linguistics.org/schema.rdf#"><s:Stiri xmlns:s="http://www.stiri.ro/crocodili">

<pos:Noun rdf:ID="crocodilii"><pos:number rdf:value="Plural" />

</pos:Noun><pos:Verb rdf:ID="se_joaca">

<pos:number rdf:value="Plural" /></pos:Verb>

</s:Stiri></rdf:RDF>

rdf schema: exemplu

Modelarea calendarelor de evenimenteinspirat de (Manjunath et al., 2008):

cal:Vevent a rdfs:Class .cal:attendee a rdf:Property ;

rdfs:domain cal:Vevent ;rdfs:range foaf:Person .

cal:location a rdf:Property .cal:dtstart a rdf:Property .cal:dtend a rdf:Property .cal:relatedTo a rdf:Property ;

rdfs:domain cal:Vevent ;rdfs:range cal:Vevent .

rdf schema: exemplu

:RoCHI08 rdf:type cal:Vevent ;cal:location [ :city "Iasi" ] ;cal:dtstart "2008-09-18T09:00:00" ;cal:dtend "2008-09-19T18:00:00" ;cal:relatedTo :RoCHI07 .

o posibila instantade eveniment

Clasele si proprietatile sunt modelate separat

Spre deosebire de paradigma orientata‐obiect, proprietatile (atributele) nu fac parte din clasa

Nu se pot exprima relatii complexe intre clase(reuniune, disjunctie,...),

nici cardinalitatea – e.g., “cel putin una”

rdf schema

Se ofera suport pentru modelareaclasificarilor de resurse

rdf schema

Strategii privind organizarea continutului (Ricci, 2004):

ierarhie unica – strategia de navigare intre conceptereprezinta insasi taxonomia adoptata

rdf schema

asocieri de continut (content mapping) – managementulcontinutului e independent de modul de navigare;pot fi folosite mai multe criterii de clasificare,

eventual pe baza meta‐datelor aferente

identificarea relatiilor de baza: sub/supra‐clase, elementeaflate pe acelasi nivel al arborelui taxonomic (peers)

rdf schema

Modelarea datelor pentru o aplicatie de ascultatCD‐uri: cdream (Victor Grigoriu, 2003)

Clase: CD – http://cdream.ro/CD

Piesa – http://cdream.ro/Piesa

rdf schema: exemplu

Aplicatia cdream (Victor Grigoriu, 2003)

Proprietati:Durata piesei (min:sec) – http://cdream.ro/LungInterpret/compozitor – http://cdream.ro/ArtistTitlul (piesei/albumului) – http://cdream.ro/Titlu

Lista pieselor de pe album – http://cdream.ro/Contine(are ca obiect un rdf:Seq)

Genul muzical – http://cdream.ro/GenMuzicalNumele artistului – http://cdream.ro/Nume

rdf schema: exemplu

Restrictii:Proprietatea Contine se aplica numai clasei CDProprietatea Lung este specifica doar clasei Piesa

Proprietatea Nume se asociaza autorilor,reprezentati ca resurse (noduri blanc)

rdf schema: exemplu

Aplicatia cdream (Victor Grigoriu, 2003)Schema RDF are urmatoarea structura:

<http://cdream.ro/CD> <rdf:type> <rdfs:Class> .<http://cdream.ro/Piesa> <rdf:type> <rdfs:Class> .<http://cdream.ro/Artist> <rdf:type> <rdf:Property> .<http://cdream.ro/Artist> <rdfs:domain> <http://cdream.ro/CD> .<http://cdream.ro/Artist> <rdfs:range> <rdfs:Resource> .<http://cdream.ro/Lung> <rdf:type> <rdf:Property> .<http://cdream.ro/Lung> <rdfs:domain> <http://cdream.ro/Piesa>.<http://cdream.ro/Lung> <rdfs:range> <rdfs:Literal> .

rdf schema: exemplu

Aplicatia cdream (Victor Grigoriu, 2003)Schema RDF are urmatoarea structura – continuare:

<http://cdream.ro/Contine> <rdf:type> <rdf:Property> .<http://cdream.ro/Contine> <rdfs:domain> <http://cdream.ro/CD>.<http://cdream.ro/Contine> <rdfs:range> <rdf:Seq> .<http://cdream.ro/Nume> <rdf:type> <rdf:Property> .<http://cdream.ro/Nume> <rdfs:domain> <rdfs:Resource>.<http://cdream.ro/Nume> <rdfs:range> <rdfs:Literal> ....

rdf schema: exemplu

implementare in limbajul C++,folosind biblioteca Redland – sub Linux

procesarea datelor RDF a recurs la analizorul Raptor

interfata cu utilizatorul bazata pe Qt

rdf schema: exemplu

Reprezinta un model de specificare explicitaa relatiilor dintre clase de “lucruri” de interes

rdf schema

Pune bazele efectuarii automate de inferentee.g., “descoperirea” relatiilor intre resurse – contrast cu OOP unde relatiile de dependenta sunt specificate apriori

rdf schema

Pune bazele efectuarii automate de inferente

Pentru subclase, avind triple de forma:A rdfs:subclassOf B .

r rdf:type A .putem deduce:

r rdf:type B .

rdf schema

triplu dedus(inferred triple)

Pentru subproprietati, avind triple de forma:P rdfs:subPropertyOf R .

A P B .putem deduce:

A R B .

rdf schema

In cazul specificarii domeniului, avind triple de forma:P rdfs:domain D .

x P y .putem deduce:

x rdf:type D .

rdf schema

In cazul specificarii intervalului, avind triple de forma:P rdfs:range R .

x P y .putem deduce:

y rdf:type R .

rdf schema

Modelarea unui web privitor la familii de persoane::FemeieMaritata rdfs:subClassOf :Femeie .:numeDeFata rdfs:domain :FemeieMaritata .

La nivel de instante, avem specificat::Raluca :numeDeFata "Morosan" .

Putem deduce automat ca:Raluca rdf:type :Femeie .

rdf schema: exemplu

Modelarea unui web privitor la familii de persoane:

rdf schema: exemplu

Generalizind, avind disponibile triplele:P rdfs:domain D .

D rdfs:subClassOf C .putem deduce:P rdfs:domain C .

in RDF Schema, mostenirea inseamna de fapt inferenta

rdf schema

Desi sintactic nu exista suport pentru specificareaoperatiilor cu clase (intersectie, reuniune),

le putem exprima folosind regulile de inferenta(Allemang & Hendler, 2008)

modelling patterns

rdf schema: sabloane

Intersectia de multimi (clase):C rdfs:subClassOf A .C rdfs:subClassOf B .

avind dat triplulr rdf:type C .

se poate deduce:r rdf:type A .r rdf:type B .

am realizatinferenta intr‐o singura directie

Intersectia de multimi (clase) – exemplu::Masterand rdfs:subClassOf :Student .

:Masterand rdfs:subClassOf :DezvoltatorWeb .:Ciprian rdf:type :Masterand .

se poate deduce::Ciprian rdf:type :Student .

:Ciprian rdf:type :DezvoltatorWeb .

un individ apartinind claselor Student si DezvoltatorWebnu e obligatoriu sa fie membru si al clasei Masterand

Similar, se poate modela intersectia de proprietati

Reuniunea de multimi:A rdfs:subClassOf C .B rdfs:subClassOf C .

avind r rdf:type A . sau r rdf:type B .se poate deduce:

r rdf:type C .

Reuniunea de multimi – exemplu::Sit rdfs:subClassOf :Produs .

:ServiciuWeb rdfs:subClassOf :Produs .:SolutieEBanking rdf:type :ServiciuWeb .(sau :SolutieEBanking rdf:type :Sit .)

se poate deduce::SolutieEBanking rdf:type :Produs .

“Transferul” de proprietati:P rdfs:subPropertyOf Q .

avind triplulX P Y .

se poate deduce:X Q Y .

“Transferul” de proprietati:

are utilizari in reconcilierea terminologiilor

:autor rdfs:subPropertyOf dc:creator .

bib:imprumutaCarte rdfs:subPropertyOf :posedaVolum .lib:borrows rdfs:subPropertyOf :posedaVolum .

Referinte la alte resurse:

rdfs:seeAlso – proprietate care indica o resursa continindinformatii suplimentare privitoare la resursa asociata

rdf schema: alte constructii

Referinte la alte resurse:

<rdf:Description rdf:ID="MSD"><s:nume xml:lang="ro">

Master de Sisteme Distribuite</s:nume><rdfs:seeAlso rdf:resource="http://www.infoiasi.ro/msd" />

</rdf:Description>

Organizarea vocabularelor:

rdfs:isDefinedBy – subproprietate a rdfs:seeAlsoce desemneaza o legatura spre sursa primara de informatii

despre o resursa data

Modelul RDF Schema specificat in RDF Schema – fragment:<rdf:Property

rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#type"> <rdfs:isDefinedBy

rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/> <rdfs:label>type</rdfs:label> <rdfs:comment>The subject is an instance of a class.</rdfs:comment> <rdfs:range

rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/> <rdfs:domain

rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/> </rdf:Property>

class name comment

rdfs:Resource The class resource, everything.

rdfs:Literal The class of literal values, e.g. textual strings and integers.

rdf:XMLLiteral The class of XML literals values.

rdfs:Class The class of classes.

rdf:Property The class of RDF properties.

rdfs:Datatype The class of RDF datatypes.

rdf:Statement The class of RDF statements.

rdf:Bag The class of unordered containers.

rdf:Seq The class of ordered containers.

rdf:Alt The class of containers of alternatives.

rdfs:Container The class of RDF containers.

rdfs:ContainerMembershipProperty

The class of container membership properties, rdf:_1, rdf:_2, ..., all of which are subproperties of 'member'.

rdf:List The class of RDF Lists.

property name comment domain range

rdf:type The subject is an instance of a class.

rdfs:Resource rdfs:Class

rdfs:subClassOf The subject is a subclass of a class. rdfs:Class rdfs:Classrdfs:

subPropertyOfThe subject is a subpropertyof a property.

rdf:Property rdf:Property

rdfs:domain A domain of the subject property. rdf:Property rdfs:Classrdfs:range A range of the subject property. rdf:Property rdfs:Class

rdfs:label A humanreadable name for the subject.

rdfs:Resource rdfs:Literal

rdfs:comment A description of the subject resource.

rdfs:Resource rdfs:Literal

rdfs:member A member of the subject resource. rdfs:Resource rdfs:Resource

rdf schema: privire de ansamblu

property name comment domain range

rdf:first First item in the subject RDF list. rdf:List rdfs:Resource

rdf:rest Rest of the subject RDF list after the first item.

rdf:List rdf:List

rdfs:seeAlso Further information about the subject resource.

rdfs:Resource rdfs:Resource

rdfs:isDefinedBy The definition of the subject resource.

rdf:value Idiomatic property used for structured values.

rdf:subject The subject of the subject RDF statement.

rdf:Statement rdfs:Resource

rdf:predicate The predicate of the subject RDF statement.

rdf:object The object of the subject RDF statement.

Exista posibilitatea folosirii unui model conceptual mai expresiv?

intrebare

Thesaurus: a controlled vocabulary arrangedin a known order and structured so that equivalence, homographic, hierarchical,

and associative relationships among termsare displayed clearly and identified by standardized

relationship indicators

Conform ANSI/NISO Monolingual Thesaurus Standard

tezaure

Relatii

Echivalentatermenul X are (aproape) acelasi inteles cu termenul Y

“PaginaWeb” sinonim cu “document Web”

tezaure

Relatii

Omonimia (omografia)termenul X se pronunta/scrie la fel ca si Y,

dar are alt inteles

“toc” versus “toc” versus “toc”

tezaure

Relatii

Ierarhietermenul X are un inteles mai larg/restrins

decit termenul Y

“patrulater” versus “dreptunghi”

tezaure

Relatii

Asocieretermenul X este asociat termenului Y

(e.g., exista o relatie nespecificata intre ei)

“cui”/“Pink Floyd” asociat lui “ciocan”

tezaure

Un tezaur asigura urmatoarele:conceptele se descriu intr‐un mod consistent

utilizatorii experimentati pot sa‐si rafineze cautarilepentru localizarea informatiilor dorite din tezaur

utilizatorii nu trebuie sa fie familiarizaticu terminologia tehnica (particulara) folosita

tezaure

Center for Army Lessons Learned (CALL) Thesaurus

National Cancer Institute (NCI) Thesaurus

AGROVOC – indexarea multilingva a resurselor privitoarela agricultura realizata la nivelul Natiunilor Unite

tezaure: exemple

Roget’s Thesaurus – parte din proiectul Gutenbergwww.cix.co.uk/~andie/cogito/roget.shtml

WordNetwww.cogsci.princeton.edu/~wn/

schema RDF disponibila la http://xmlns.com/2001/08/wordnet/

SWAD (Semantic Web Advanced Development) Thesauruswww.w3c.rl.ac.uk/SWAD/thesaurus.html

tezaure: exemple

(Daconta, Obrst& Smith, 2003)

Simple Knowledge Organizational Systemexprimă cunoştințele în cadrul sistemelor organizaționale, în general, şi a tezaurelor, în special (Mikhalenko, 2005)

propus de Consortiul Web

model bazat pe RDF şi scheme RDF

http://www.w3.org/TR/skos-primer

tezaure: skos

Niveluri de specificare:

SKOS Core – modeleaza in special tezaureutilizeaza spatiul de nume

http://www.w3.org/2004/02/skos/core

SKOS Mapping – extensie ce permite asociereade concepte din tezaure diferite

tezaure: skos

Exemplu: definirea conceptului de instrument<skos:Concept rdf:about="#instrument">

<skos:definition>Obiect utilizat într-un anumit scop</skos:definition><skos:narrower rdf:resource="#obiect"/><skos:related rdf:resource="#unealta"/><skos:related rdf:resource="#dispozitiv"/><skos:related rdf:resource="#mecanism"/><skos:scopeNote>...</skos:scopeNote>

</skos:Concept>

tezaure: skos

Specificarea tezaurului arhivelor nationale britaniceUK Archival Thesaurus (Allemang & Hendler, 2008)

UKAT:EconomicCooperation a skos:Concept ;skos:altLabel "Economic co-operation" ;skos:broader UKAT:EconomicPolicy;skos:narrower UKAT:IndustrialCooperation,

UKAT:EconomicIntegration ;skos:prefLabel "Economic cooperation" ;skos:related UKAT:Interdependence ;skos:scopeNote "..." .

tezaure: skos

relatii dintre concepte:

broader, narrowersi related

Rafineaza conceptul de rdfs:label,oferind prefLabel, altLabel si hiddenLabel

s:rocks rdf:type skos:Concept ; skos:prefLabel "rocks"@en ; skos:altLabel "basalt"@en ; skos:altLabel "granite"@en ; skos:altLabel "slate"@en .

tezaure: skos

skos:prefLabela rdf:Property ;rdfs:label "eticheta preferata" ;rdfs:subPropertyOf rdfs:label .

Pot fi specificate si colectii de concepte via skos:Collection

agro:LapteDupaTipulDeAnimal rdf:type skos:Collection ; skos:member agro:LapteDeVaca ; skos:member agro:LapteDeCapra ; skos:member agro:LapteDeOaie .

agro:LapteDeVaca rdf:type skos:Concept ; skos:prefLabel "Lapte de vaca" .

agro:Lapte skos:narrower agro:LapteDupaTipulDeAnimal .

tezaure: skos

Coordonarea conceptelor (pre‐ si post‐coordonare)– suport pentru indexarea perechilor de concepte

s:floare skos:prefLabel "Floare"@ro . s:soare skos:prefLabel "Soare"@ro .

extindem SKOS cu proprietatea s:coordinationOf astfel:s:coordinationOf a rdf:Property ;

rdfs:domain skos:Concept ; rdfs:range rdf:List .

tezaure: skos

Cum specificam“floarea soarelui”?

Coordonarea conceptelor (pre‐ si post‐coordonare)

s:floareaSoarelui a skos:Concept ; s:coordinationOf (s:floare s:soare) ; skos:prefLabel "Floarea-soarelui"@ro .

tezaure: skos

Specificarea de relatii tranzitive intre concepte via skos:broaderTransitive si skos:narrowerTransitive

tezaure: skos

Specificarea de relatii tranzitive intre concepte via skos:broaderTransitive si skos:narrowerTransitive

tezaure: skos

detalii in Isaac & Summers, SKOS Primer, W3C, 2008

Detalii in (Magiridou et al., 2005)

Specificati in RDF(S) clasele, proprietatile si relatiileprivitoare la tipurile de angajati si artefactele asociate:

Rezumat

Modelarea taxonomiilor si tezaurelor prinRDF Schema si realizarea inferentelor simple

web05 semantic web: rdf schema

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