rdf and rdf schema for ontology specification

Mobile Web ServicesMobile Web Services

RDF and RDF Schema for RDF and RDF Schema for ontology specificationontology specification

Presenter: Chen Jen

OutlineOutline

• IntroductionIntroduction

• RDF discussionRDF discussion

• Beyond RDF SchemaBeyond RDF Schema

• ReferenceReference

IntroductionIntroduction

• Metadata decide data’s importance Metadata decide data’s importance by selfby self

• No require human or computer to No require human or computer to determine its relevancedetermine its relevance

• Metadata need accepted vocabularyMetadata need accepted vocabulary


• Resource Description Framework Resource Description Framework (RDF) was developed(RDF) was developed

• Uniform Resource Identifiers (URIs) Uniform Resource Identifiers (URIs) identify resourcesidentify resources

• Assertion format is based on XML Assertion format is based on XML notationnotation


• Resource assertion has three objectsResource assertion has three objects– Resource itselfResource itself– Property nameProperty name– StatementStatement

• Three objects is the same in RDFThree objects is the same in RDF– SubjectSubject– PredicatePredicate– objectobject

RDF discussion RDF discussion

• RDF applicationRDF application

• RDF graph modelsRDF graph models

• RDF XML syntaxRDF XML syntax

• RDF vocabularies and schemasRDF vocabularies and schemas

• RDF schema languageRDF schema language

RDF applicationsRDF applications

• Mobile terminal capabilitiesMobile terminal capabilities– Adapt their content for each terminalAdapt their content for each terminal

•Screen size, screen resolution, color support Screen size, screen resolution, color support etc.etc.

– Indicate relative degrees of preferenceIndicate relative degrees of preference•Client prefers markup qualityClient prefers markup quality

RDF applicationsRDF applications

• User privacy preferencesUser privacy preferences– Network access constraintsNetwork access constraints

•Specify on WLAN or cellular network Specify on WLAN or cellular network

RDF graph modelsRDF graph models

Terminal

320x240yes

Text/htmlImage/gif

yes

1.0 yes

HardwarePlatform

SoftwarePlatform

BrowserUA

ImageCapable ScreenSize

CcppAccept JavaEnable

XhtmlVersion TablesCapable

(1)

(2)

(3)

(4)

RDF graph modelsRDF graph models

• Resource = Source node Resource = Source node (1)(1)

• Property name = Arc Property name = Arc (2)(2)

• Property value = Final node Property value = Final node (3)(3)

• Structured information resource = Structured information resource = Blank node Blank node (4)(4)

RDF XML syntaxRDF XML syntax

TerminalHardware

yes 320x240 prf:#HardwarePlatform

ImageCapableScreenSize

type


• <<rdf:RDFrdf:RDF> = RDF resource representation> = RDF resource representation• XML namespaceXML namespace

– xmlns:rdfxmlns:rdf for W3C RDF specific term for W3C RDF specific term– xmlns:prfxmlns:prf for WAP Forum’s UAProf term for WAP Forum’s UAProf term

• Term prefixed withTerm prefixed with– rdfrdf correspond W3C URI correspond W3C URI– prfprf correspond WAP Forum URI correspond WAP Forum URI


• <<DescriptionDescription> is> is– Describe resourceDescribe resource– Likeness of nested elementLikeness of nested element


yes

TerminalHardware

prf:#HardwarePlatform

ImageCapable

ScreenSize

type

...Property prf:#HardwarePlatform

type

domain

value

...Property prf:#HardwarePlatform

type

domain

320x240

value


• DomainDomain is defined by another is defined by another associated resource URIassociated resource URI

• <<commentcomment> replace RDF <value>> replace RDF <value>

• DTD (Document Type Definition) can DTD (Document Type Definition) can be used in XMLbe used in XML


• <Bag> = unordered group of resources<Bag> = unordered group of resources– rdf:Bagrdf:Bag

• <Sequence> = ordered group<Sequence> = ordered group– rdf:Seqrdf:Seq

• <Alternative> = alternative values<Alternative> = alternative values– rdf:Altrdf:Alt

• <<rdf:lirdf:li> = separate line item> = separate line item

RDF vocabularies and RDF vocabularies and schemasschemas

• Vocabulary = collection of resources and Vocabulary = collection of resources and propertiesproperties– PDA, Phone, GPS, etc.PDA, Phone, GPS, etc.

• RDF schema is used by object-orientedRDF schema is used by object-oriented– Namespace Namespace rdfsrdfs = RDF schema vocabulary = RDF schema vocabulary

RDF schema languageRDF schema language

MultiFunctionMobile

Phone PDA

Mobile Terminal

RDFS class

type

subClassOf

subClassOf

RDF schema language -RDF schema language -RDFS classRDFS class

• Class = ResourceClass = Resource• rdf:typerdf:type property = rdf:Class property = rdf:Class• Rdfs:subClassOfRdfs:subClassOf = parent resource = parent resource

– MobileTerminal is classMobileTerminal is class– Phone, PDA are subclassesPhone, PDA are subclasses

RDF schema language –RDF schema language –RDFS properties and property RDFS properties and property constraintsconstraints• rdf:typerdf:type value is value is rdf:Propertyrdf:Property• domaindomain constrain property to be associa constrain property to be associa

ted with certain resourcested with certain resources• rangerange define that property can have valu define that property can have valu

ee• rdfs:subProperyOfrdfs:subProperyOf property is organized. property is organized.

– GIFcapableGIFcapable is sub-property of UAProf’s is sub-property of UAProf’s ImImageCapableageCapable property property

RDF schema language –RDF schema language –Component design with RDFSComponent design with RDFS

• Property-centric specification has Property-centric specification has many benefitsmany benefits– Independently of classIndependently of class– No need to redefineNo need to redefine– Object-oriented programming languageObject-oriented programming language– No include all applicable propertiesNo include all applicable properties

Beyond RDF SchemaBeyond RDF Schema

• The Web Ontology Language (OWL)The Web Ontology Language (OWL)

• Defense Advanced Research Projects Defense Advanced Research Projects Agency (DARPA)Agency (DARPA)

• DARPA Agent Markup Language DARPA Agent Markup Language (DAML)(DAML)– Facilitate the concept of the SemanticFacilitate the concept of the Semantic

• Ontology Inference Layer (OIL)Ontology Inference Layer (OIL)– Knowledge-representation researchKnowledge-representation research


• OWL is published as W3COWL is published as W3C– Need of different communityNeed of different community– Different levels of ontology Different levels of ontology

sophisticationsophistication

• OWL Description Logics (DL)OWL Description Logics (DL)– Require strict typeRequire strict type

• OWL FullOWL Full– No have any limitationNo have any limitation


• OWL-based Web Service Ontology OWL-based Web Service Ontology (OWL-S)(OWL-S)– Automation of services on the Semantic WebAutomation of services on the Semantic Web– Core set of markup language constructCore set of markup language construct

• Automation of taskAutomation of task– Web service discoveryWeb service discovery– InvocationInvocation– Composition and interoperationComposition and interoperation– Execution monitoringExecution monitoring


• Web service discoveryWeb service discovery– Automatic offer specific servicesAutomatic offer specific services

• Web service invocationWeb service invocation– Web service function to invokeWeb service function to invoke

• Interoperation and compositionInteroperation and composition– Multiple Web services combine a Multiple Web services combine a

composite servicecomposite service


• Monitoring trackMonitoring track– Aware and progress of their requestAware and progress of their request

ReferenceReference

• Ariel Pashtan, Mobile Web Service. Page Ariel Pashtan, Mobile Web Service. Page 138 ~153. 138 ~153.

rdf and rdf schema for ontology specification

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