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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
IntroductionIntroduction
• 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
IntroductionIntroduction
• 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 XML syntaxRDF XML syntax
• <<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
RDF XML syntaxRDF XML syntax
• <<DescriptionDescription> is> is– Describe resourceDescribe resource– Likeness of nested elementLikeness of nested element
RDF XML syntaxRDF XML syntax
yes
TerminalHardware
prf:#HardwarePlatform
ImageCapable
ScreenSize
type
...Property prf:#HardwarePlatform
type
domain
value
...Property prf:#HardwarePlatform
type
domain
320x240
value
RDF XML syntaxRDF XML syntax
• 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
RDF XML syntaxRDF XML syntax
• <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
Beyond RDF SchemaBeyond RDF Schema
• 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
Beyond RDF SchemaBeyond RDF Schema
• 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
Beyond RDF SchemaBeyond RDF Schema
• 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
Beyond RDF SchemaBeyond RDF Schema
• 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.
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