web05 semantic web: rdf schema
DESCRIPTION
Aspecte privitoare la specificarea schemelor RDF in vederea definirii de taxonomii, tezaure si alte modele de reprezentare a cunostintelor.TRANSCRIPT
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Web semantic
Dr. SabinCorneliu BuragaFacultatea de Informatica
Universitatea “A.I.Cuza” – Iasi, Romania
http://www.infoiasi.ro/~busaco/
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Realizarea inferentelor via RDF(S)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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“Toate erau laolalta – dupa aceea a venit minteasi le‐a pus in ordine.”
Anaxagoras
Dr. Sabin Buraga http://www.purl.org/net/busaco
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constatare
Declaratiile RDF se situeaza la nivel de instante (indivizi)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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constatare
Lipseste un mecanism de declarare a unui vocabular
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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?
Dr. Sabin Buraga http://www.purl.org/net/busaco
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necesitati
Un mecanism de specificarea unui model de cunostinte privitor la un web
specificarea unei taxonomii a resurselor
Dr. Sabin Buraga http://www.purl.org/net/busaco
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necesitati
O modalitate de a specificarelatiile dintre (clase de) resurse
RDF este un model care permite specificarea de relatiiintre doua obiecte
Dr. Sabin Buraga http://www.purl.org/net/busaco
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necesitati
Ne‐ar fi util un model ce permite definireaunei taxonomii, in termeni de clase, superclase
si subclase de resurse
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii
Taxonomia reprezintă studiul principiilorgenerale de clasificare ştiințifică,
i.e. clasificarea sistematică
detalii in (Daum et al., 2003)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii
Taxonomie ≡ arbore:
noduri – concepte (clase)
relații dintre noduri – relații de sub‐/supra‐clasificare (generalizare/specializare)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii
Fiecare nod (entitate) posedao proprietate specifica, proprietate caracteristica
sub‐clasei din care face parte
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii: exemplu
Conform (Alan Rector et al., 2004)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii: exemplu
Conform (Christian Ricci, 2004)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Bernstein et al., 2005
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii: utilizari
Clasificarea resurselor
model simplu de clasificare
taxonomie = ontologie simpla
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii: utilizari
exemplu mentionat de (Bouquet, Serafini & Zanobini, 2005)
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taxonomii: utilizari
Structuri de directoare de fisiere
Categorii de situri Web – cataloage, directoriesOpen Directory: dmoz.org
Comert electronicUniversal Standard Products and Services Classification:
www.eccma.org
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii: utilizari
Clasificarea serviciilor Webse realizeaza via tModel,
folosindu‐se North American Industry Classification System
Dr. Sabin Buraga http://www.purl.org/net/busaco
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taxonomii: model
Modelarea poate fi realizata via scheme RDF
Dr. Sabin Buraga http://www.purl.org/net/busaco
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rdf schema
Permite definirea de taxonomii
în termeni de clase, super‐clase şi sub‐clase de resurse
(Brickley & Guha, 2004)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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rdf schema
Recomandare a Consortiului Web
www.w3.org/TR/rdfschema/
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Clasa (Class) & proprietatea (Property)
Persoana, type, ClassareIdentitate, type, Property
Aplicatie, type, ClassruleazaPe, type, Property
rdf schema: terminologie
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Tip (type), sub‐clasa (subClassOf), domeniu (domain), interval (range)
Autor, subClassOf, PersoanaCompanie, subClassOf, Producator
esteStudent, domain, PersoanaesteStudent, range, xsd:Boolean
areNume, range, xsd:String
rdf schema: terminologie
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
rdf schema: terminologie
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Clasele specifica resurse Web (identificate de URI):pagini
tipuri de documentebaze de datepersoane…
rdf schema: model
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Resursele apartinind unei clase = instante
clase specificate via RDF Schemainstantele sunt exprimate prin RDF
rdf schema: model
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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rdf schema: exemplu
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Remarca:nu e obligatoriu sa definim conceptul Integer
ipoteza lumilor deschisecontrast cu modelul bazelor de date clasice
rdf schema: model
Dr. Sabin Buraga http://www.purl.org/net/busaco
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rdf schema: exemplu
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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rdf schema: exemplu
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Se ofera suport pentru modelareaclasificarilor de resurse
rdf schema
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Strategii privind organizarea continutului (Ricci, 2004):
ierarhie unica – strategia de navigare intre conceptereprezinta insasi taxonomia adoptata
rdf schema
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Strategii privind organizarea continutului (Ricci, 2004):
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Strategii privind organizarea continutului (Ricci, 2004):
rdf schema
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Aplicatia cdream (Victor Grigoriu, 2003)
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Aplicatia cdream (Victor Grigoriu, 2003)
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Reprezinta un model de specificare explicitaa relatiilor dintre clase de “lucruri” de interes
rdf schema
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Pune bazele efectuarii automate de inferentee.g., “descoperirea” relatiilor intre resurse – contrast cu OOP unde relatiile de dependenta sunt specificate apriori
rdf schema
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Pune bazele efectuarii automate de inferente
Pentru subproprietati, avind triple de forma:P rdfs:subPropertyOf R .
A P B .putem deduce:
A R B .
rdf schema
triplu dedus(inferred triple)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Pune bazele efectuarii automate de inferente
In cazul specificarii domeniului, avind triple de forma:P rdfs:domain D .
x P y .putem deduce:
x rdf:type D .
rdf schema
triplu dedus(inferred triple)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Pune bazele efectuarii automate de inferente
In cazul specificarii intervalului, avind triple de forma:P rdfs:range R .
x P y .putem deduce:
y rdf:type R .
rdf schema
triplu dedus(inferred triple)
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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Modelarea unui web privitor la familii de persoane:
rdf schema: exemplu
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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 .
rdf schema: sabloane
am realizatinferenta intr‐o singura directie
Dr. Sabin Buraga http://www.purl.org/net/busaco
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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
rdf schema: sabloane
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Similar, se poate modela intersectia de proprietati
rdf schema: sabloane
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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 .
rdf schema: sabloane
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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 .
rdf schema: sabloane
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
“Transferul” de proprietati:P rdfs:subPropertyOf Q .
avind triplulX P Y .
se poate deduce:X Q Y .
rdf schema: sabloane
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
“Transferul” de proprietati:
are utilizari in reconcilierea terminologiilor
:autor rdfs:subPropertyOf dc:creator .
bib:imprumutaCarte rdfs:subPropertyOf :posedaVolum .lib:borrows rdfs:subPropertyOf :posedaVolum .
rdf schema: sabloane
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Referinte la alte resurse:
rdfs:seeAlso – proprietate care indica o resursa continindinformatii suplimentare privitoare la resursa asociata
rdf schema: alte constructii
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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" /><!-- informatii suplimentare -->
</rdf:Description>
rdf schema: alte constructii
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Organizarea vocabularelor:
rdfs:isDefinedBy – subproprietate a rdfs:seeAlsoce desemneaza o legatura spre sursa primara de informatii
despre o resursa data
rdf schema: alte constructii
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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>
rdf schema: alte constructii
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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.
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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.
rdfs:Resource rdfs:Resource
rdf:value Idiomatic property used for structured values.
rdfs:Resource rdfs:Resource
rdf:subject The subject of the subject RDF statement.
rdf:Statement rdfs:Resource
rdf:predicate The predicate of the subject RDF statement.
rdf:Statement rdfs:Resource
rdf:object The object of the subject RDF statement.
rdf:Statement rdfs:Resource
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Exista posibilitatea folosirii unui model conceptual mai expresiv?
intrebare
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Relatii
Echivalentatermenul X are (aproape) acelasi inteles cu termenul Y
“PaginaWeb” sinonim cu “document Web”
tezaure
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Relatii
Omonimia (omografia)termenul X se pronunta/scrie la fel ca si Y,
dar are alt inteles
“toc” versus “toc” versus “toc”
tezaure
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Relatii
Ierarhietermenul X are un inteles mai larg/restrins
decit termenul Y
“patrulater” versus “dreptunghi”
tezaure
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Relatii
Asocieretermenul X este asociat termenului Y
(e.g., exista o relatie nespecificata intre ei)
“cui”/“Pink Floyd” asociat lui “ciocan”
tezaure
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
tezaure: exemple
(Daconta, Obrst& Smith, 2003)
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Exemplu: definirea conceptului de instrument<skos:Concept rdf:about="#instrument">
<skos:definition>Obiect utilizat într-un anumit scop</skos:definition><!-- specializare a unui alt concept --><skos:narrower rdf:resource="#obiect"/><!-- concepte înrudite --><skos:related rdf:resource="#unealta"/><skos:related rdf:resource="#dispozitiv"/><skos:related rdf:resource="#mecanism"/><skos:scopeNote>...</skos:scopeNote>
</skos:Concept>
tezaure: skos
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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 .
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
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”?
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Coordonarea conceptelor (pre‐ si post‐coordonare)
s:floareaSoarelui a skos:Concept ; s:coordinationOf (s:floare s:soare) ; skos:prefLabel "Floarea-soarelui"@ro .
tezaure: skos
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Specificarea de relatii tranzitive intre concepte via skos:broaderTransitive si skos:narrowerTransitive
tezaure: skos
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Specificarea de relatii tranzitive intre concepte via skos:broaderTransitive si skos:narrowerTransitive
tezaure: skos
detalii in Isaac & Summers, SKOS Primer, W3C, 2008
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Detalii in (Magiridou et al., 2005)
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Specificati in RDF(S) clasele, proprietatile si relatiileprivitoare la tipurile de angajati si artefactele asociate:
tema
(Dac
onta
et a
l., 2
00
3)
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
Rezumat
Modelarea taxonomiilor si tezaurelor prinRDF Schema si realizarea inferentelor simple
Dr. Sabin Buraga http://www.purl.org/net/busaco
Semantic Web <?xml version=“1.0” ?><curs desc=“…” />
?