服务计算基础之语义Web服务

2008-2010byLiWeigang.Allrightsreserved.服务计算基础服务计算基础主讲：李伟刚西北工业大学软件与微电子学院2008-2010byLiWeigang.Allrightsreserved.第九章第九章 语义语义Web服务服务2008-2010byLiWeigang.Allrightsreserved.主要内容主要内容l概述l语义网l语义Web服务2008-2010byLiWeigang.Allrightsreserved.第一节第一节 概述概述2008-2010byLiWeigang.Allrightsreserved.l语义是事物的观察者给事物本身赋予的含义，一致共享的语义构成观察者对事物的知识，是观察者之间互相交流的基础。l语义网通过给万维网上的文档(如:HTML)添加能够被计算机理解的语义(Metadata)，从而使整个万维网中现存的信息发展成一个巨大的全球信息库、知识库。语义和语义网语义和语义网2008-2010byLiWeigang.Allrightsreserved.lWeb服务使用标准的、规范的XML进行描述，包括消息格式、传输协议和位置，隐藏了实现服务的细节。lWSDL从句法层面对Web服务的功能进行描述，包括4个不同的方面：数据类型、消息、操作和访问端口。l这只是提供了Web服务的接口描述，对服务的行为约束和属性描述缺乏进一步的支持。l缺陷数据管理有序性与Web上信息无序性；搜索引擎查全查准要求与服务描述缺语义；信息获取效率与Web海量动态数据。语义语义Web服务服务2008-2010byLiWeigang.Allrightsreserved.l语义Web服务的主要方法是利用Ontology来描述Web服务，通过带有语义信息的Web服务来实现服务的自动发现，调用和组合。l语义Web和Web服务是语义Web服务的两大支撑技术。lOWL-S是连接两大技术的桥梁。目前对语义Web服务标记语言研究最典型的组织就是DARPA（DefenceAdvancedResearchProjectsAgency）组织，其研究组OWLServicesCoalition提出了语义Web服务标记语言OWL-S语义语义Web服务服务2008-2010byLiWeigang.Allrightsreserved.第二节第二节 语义网语义网2008-2010byLiWeigang.Allrightsreserved.SemanticWeb的由来的由来lWebwas“invented”byTimBerners-Lee,aphysicistworkingatCERNlTBLsoriginalvisionoftheWebwasmuchmoreambitiousthantherealityoftheexisting(syntactic)Web:lTBL(andothers)havesincebeenworkingtowardsrealisingthisvision,whichhasbecomeknownastheSemanticWebE.g.,articleinMay2001issueofScientificAmerican“.agoaloftheWebwasthat,iftheinteractionbetweenpersonandhypertextcouldbesointuitivethatthemachine-readableinformationspacegaveanaccuraterepresentationofthestateofpeoplesthoughts,interactions,andworkpatterns,thenmachine analysiscouldbecomeaverypowerfulmanagementtool,seeingpatternsinourworkandfacilitatingourworkingtogetherthroughthetypicalproblemswhichbesetthemanagementoflargeorganizations.”2008-2010byLiWeigang.Allrightsreserved.lTheSemanticWebisanextensionofthecurrentwebinwhichinformationisgivenwell-definedmeaning,betterenablingcomputersandpeopletoworkinco-operation.TimBerners-Lee,JamesHendler,OraLassila,TheSemanticWeb,ScientificAmerican,May2001SemanticWeb的定义的定义2008-2010byLiWeigang.Allrightsreserved.SemanticWeb的架构的相关标准的架构的相关标准 本体层本体层本体层本体层1.1.1.1.以谓词演算为基础的语言以谓词演算为基础的语言以谓词演算为基础的语言以谓词演算为基础的语言KIFKIF-based Ontolingua,CycL,-based Ontolingua,CycL,Loom,Frame-LogicLoom,Frame-Logic2.2.2.2.基于基于基于基于XMLXML的本体表示语言的本体表示语言的本体表示语言的本体表示语言SHOE,XOL,OML&CKML,SHOE,XOL,OML&CKML,RDFSRDFS,Riboweb,OIL,DAML+OIL,OWLRiboweb,OIL,DAML+OIL,OWL规则层规则层规则层规则层RuleMLRuleML、HornMLHornML、DLMLDLML逻辑框架层逻辑框架层逻辑框架层逻辑框架层FOLFOL、HOLHOL、DLDL、Horn-logicHorn-logic、OMDocOMDoc下四层已下四层已下四层已下四层已经发展的经发展的经发展的经发展的比较成熟比较成熟比较成熟比较成熟与完善与完善与完善与完善1.数据格式层2.信息表示层3.元数据表示层4.元数据定义层5.本体层6.规则层7.逻辑框架层8.证据层9.高信度Web层We are here!2008-2010byLiWeigang.Allrightsreserved.l本体(ontology)aphilosophicaldiscipline,branchofphilosophythatdealwiththenatureandtheorganizationofreality.lScienceofbeinglTriestoanswerthequestions:whatisbeing?whatarethefeaturescommontoallbeings?本体本体(ontology)的定义的定义2008-2010byLiWeigang.Allrightsreserved.Ontology is a formal,explicit specification of a shared conceptualization Gruber 要点：要点：Conceptualization:anabstractmodelofphenomenaintheworldbyhavingidentifiedtherelevantconceptsofthosephenomena.Explicit:thetypeofconceptsused,andtheconstraintsontheiruseareexplicitlydefined.Formal:thefactthattheontologyshouldbemachinereadable.Shared:ontologyshouldcaptureconsensualknowledgeacceptedbythecommunities本体本体(ontology)的定义的定义2008-2010byLiWeigang.Allrightsreserved.lWhatisaconcept?Differentcommunitieshavedifferentnotionsonwhataconceptmeans:lformalconceptslconceptlabellterminologylframeorOOlThereism:nrelationshipbetweenwordsandconceptsdifferentwordsmayrefertothesameconceptsawordmayrefertoseveralconceptslOntologylanguagesshouldprovidemeansformakingthisdifferenceexplicit本体本体(ontology)的定义的定义2008-2010byLiWeigang.Allrightsreserved.lClassesconceptsofthedomainortasks,whichareusuallyorganizedintaxonomiesinuniv-ontology:studentandprofessoraretwoclasseslRelationsatypeofinteractionbetweenconceptsofthedomainsuchas:subclass-of,is-a本体的构成本体的构成2008-2010byLiWeigang.Allrightsreserved.lFunctionsAspecialcaseofrelationsinwhichthen-thelementoftherelationshipisuniqueforthen-1precedingelementsSuchas:Price-of-a-used-carcandefinethecalculationofthepriceofthesecond-handcaronthecar-model,manufacturingdataandkilometerslAxioms（公理）ModelsentencesthatarealwaystrueSuchas:ifthestudentattendsbothAandBcourse,thenheorshemustbeasecondyearstudent本体的构成本体的构成2008-2010byLiWeigang.Allrightsreserved.lInstancesrepresentspecificelementssuchas:StudentcalledPeterisaninstanceofStudentclass本体的构成本体的构成2008-2010byLiWeigang.Allrightsreserved.lRDF data modelResourceslAresourceisathingyoutalkabout(canreference)lResourceshaveURIs(UniformResourceIdentifiers)lRDFdefinitionsarethemselvesResourcesPropertieslAspecialkindofresources,describerelationsbetweenresources.(subject,predicate,object)资源描述框架资源描述框架(RDF)2008-2010byLiWeigang.Allrightsreserved.DiscreteMathematicsDavidBillingtonAssociateProfessorRDF2008-2010byLiWeigang.Allrightsreserved.lClasses and propertiesclasses:asetofobjects,rdfs:Classinstances:individualobjectproperty:addrestrictionsonobjects,rdfs:PropertylClass and hierarchies资源描述框架模式资源描述框架模式(RDFS)2008-2010byLiWeigang.Allrightsreserved.Restrictions:lCoursesmusttaughtbyacademicstaffmembersonlylMichaelMaherisaprofessorlifweknow,professorisasubclassofacademicstafflMichaelMaherisallowedtoteachcourseslPropertyhierarchies资源描述框架模式资源描述框架模式(RDFS)2008-2010byLiWeigang.Allrightsreserved.lSomeimportantterminologiesinRDFSrdf:type类的实例和类之间的关系rdfs:subClassOf子类和类之间的关系rdfs:subPropertyOf子性质关系rdfs:domain性质的定义域rdfs:range性质的值域资源描述框架模式资源描述框架模式(RDFS)2008-2010byLiWeigang.Allrightsreserved.RDF和RDFS的关系2008-2010byLiWeigang.Allrightsreserved.lRDF/RDFSlimitationsLocalscopeofproperties.cowseatonlyplantsDisjointnessofclasses.MaleandfemaleBooleancombinationsofclasses.(,)Cardinalityrestrictions,propertyvaluerestriction.personandparents,teacherandcoursesSpecialcharacteristicsofpropertieslSuperviseandIsSupervisedbyRDF的局限性的局限性2008-2010byLiWeigang.Allrightsreserved.lRequirements for ontology languageawell-definedsyntaxaformalsemantics(convenienttoreason)convenienceofexpressionefficientreasoningsupportsufficientexpressivepower本体描述语言本体描述语言OWL2008-2010byLiWeigang.Allrightsreserved.lOWLisbuiltontopofRDFlOWLisforprocessinginformationontheweblOWLwasdesignedtobeinterpretedbycomputerslOWLwasnotdesignedforbeingreadbypeoplelOWLiswritteninXMLlOWLisawebstandard什么是什么是OWL2008-2010byLiWeigang.Allrightsreserved.Origins of OWLDAMLDAML+OILDAML=DARPA Agent Markup LanguageOIL=Ontology Inference LayerOWL is now a W3C Recommendation!OILOWLRDFAll were influenced by RDFOWL2008-2010byLiWeigang.Allrightsreserved.LogicfoundationofOWL:DescriptionLanguagelOWL Lite:ClassificationhierarchySimpleconstraintsl OWL DL(Description Logic):MaximalexpressivenessWhilemaintainingtractabilityStandardformalisationl OWL Full:VeryhighexpressivenessLoosingtractabilityNon-standardformalisationAllsyntacticfreedomofRDF(self-modifying)Syntactic layeringSemantic layeringFullDLLiteLayeredlanguageofOWL2008-2010byLiWeigang.Allrightsreserved.OWL2008-2010byLiWeigang.Allrightsreserved.OWL2008-2010byLiWeigang.Allrightsreserved.OWL2008-2010byLiWeigang.Allrightsreserved.OWLExample:animals2008-2010byLiWeigang.Allrightsreserved.第三节第三节 语义语义Web服务服务2008-2010byLiWeigang.Allrightsreserved.WWWURI,HTML,HTTPBringingthewebtoitsfullpotentialSemantic WebRDF,RDF(S),OWLDynamicWeb ServicesUDDI,WSDL,SOAPStaticSemantic WebServicesMotivation of Semantic Web Service2008-2010byLiWeigang.Allrightsreserved.Semantic Web Technology+Web Service TechnologySemantic Web Services=Semantic Web Servicesallowmachinesupporteddatainterpretationontologiesasdatamodelautomateddiscovery,selection,composition,andweb-basedexecutionofservicesasintegratedsolutionforrealizingthevisionofthenextgenerationoftheWeb.2008-2010byLiWeigang.Allrightsreserved.Semantic Web ServiceslDefineexhaustivedescriptionframeworksfordescribingWebServicesandrelatedaspects(Web Service Description Ontologies)lSupportontologiesasunderlyingdatamodeltoallowmachinesupporteddatainterpretation(Semantic Web aspect)lDefinesemanticallydriventechnologiesforautomationoftheWebServiceusageprocess(Web Service aspect)2008-2010byLiWeigang.Allrightsreserved.Semantic Web ServicesUsageProcess:lPublication:MaketheavailabledescriptionofthecapabilityofaservicelDiscovery:LocatedifferentservicessuitableforagiventasklSelection:ChoosethemostappropriateservicesamongtheavailableoneslComposition:CombineservicestoachieveagoallMediation:Solvemismatches(data,protocol,process)amongthecombinedlExecution:Invokeservicesfollowingprogrammaticconventions2008-2010byLiWeigang.Allrightsreserved.Semantic Web ServicesExecutionsupport:lMonitoring:ControltheexecutionprocesslCompensation:ProvidetransactionalsupportandundoormitigateunwantedeffectslReplacement:FacilitatethesubstitutionofservicesbyequivalentoneslAuditing:Verifythatserviceexecutionoccurredintheexpectedway2008-2010byLiWeigang.Allrightsreserved.Semantic Web ServicesWithSemantic:Notonlyaninterfacedescription,butalsothecapabilityoftheservice.Logicreasoningenhancedservicediscoveryandcomposition.Canbedoneautomatically.2008-2010byLiWeigang.Allrightsreserved.lOWL-S:OntologyWebLanguageforServiceslWSMLlWSDL-Sl语义语义Web服务标记语言服务标记语言2008-2010byLiWeigang.Allrightsreserved.lOntologyOWL-SisanOWLontologytodescribeWebservicesOWL-SleveragesonOWLtolSupportcapabilitybaseddiscoveryofWebserviceslSupportautomaticcompositionofWebServiceslSupportautomaticinvocationofWebservicesComplete do not competelOWL-SdoesnotaimtoreplacetheWebservicesstandardsratherOWL-SattemptstoprovideasemanticlayerOWL-SreliesonWSDLforWebserviceinvocation(see Grounding)OWL-sExpandsUDDIforWebservicediscovery(OWL-S/UDDI mapping)OWL-S概述概述2008-2010byLiWeigang.Allrightsreserved.OWL-S整体结构整体结构ResourceServiceServiceProfileServiceModelServiceGroundingcommunication protocol(RPC,HTTP,)port numbermarshalling/serializationinput typesoutput typespreconditionseffectsprocess flowcomposition hierarchyprocess definitionsprovidespresents(what it does)describedby(how it works)supports(how to access)2008-2010byLiWeigang.Allrightsreserved.服务概要服务概要ResourceServiceServiceProfileServiceModelServiceGroundingprovidespresents(what it does)describedby(how it works)supports(how to access)2008-2010byLiWeigang.Allrightsreserved.服务概要服务概要ServiceProfilePresentedbyaservice.Representswhat the service providesTwomainuses:1.AdvertisementsofWebServicescapabilities(non-functionalproperties,QoS,Description,classification,etc.)2.RequestofWebserviceswithagivensetofcapabilitiesProfile does not specify use/invocation!2008-2010byLiWeigang.Allrightsreserved.Non Functional PropertiesFunctionality Description服务概要服务概要2008-2010byLiWeigang.Allrightsreserved.lSummarizestheabstractcapabilityofaservicelFunctionalspecificationofwhattheserviceprovidesintermsofparameters,subclassedas:preconditionsinputsoutputseffects服务概要服务概要功能性描述功能性描述2008-2010byLiWeigang.Allrightsreserved.lPreconditionsSetofconditionsthatshouldholdpriortoserviceinvocationlInputsSetofnecessaryinputsthattherequestershouldprovidetoinvoketheservicelOutputsResultsthattherequestershouldexpectafterinteractionwiththeserviceprovideriscompletedlEffectsSetofstatementsthatshouldholdtrueiftheserviceisinvokedsuccessfullyOftenrefertoreal-worldeffectslPackagebeingdelivered,orCreditcardbeingdebited服务概要服务概要功能性描述：参数功能性描述：参数2008-2010byLiWeigang.Allrightsreserved.lProvidessupportinginformationabouttheservicelTheseincludeserviceNametextDescriptionhas_processqualityRatingserviceParameterserviceCategorycontactInformation服务概要服务概要非功能性描述非功能性描述2008-2010byLiWeigang.Allrightsreserved.lSub-classingtheProfilemodelfacilitatesthecreationandspecialisationofservicecategorieslEachsubclasscan:IntroducenewpropertiesPlacerestrictionsonexistingpropertieslSub-classingcanalsobeusedtospecialiserequestsforservicelAnexampleProfileHierarchyisprovided,butotherscouldjustaseasilybedefined服务概要服务概要层次层次2008-2010byLiWeigang.Allrightsreserved.服务概要服务概要层次：例子层次：例子2008-2010byLiWeigang.Allrightsreserved.ResourceServiceServiceProfileServiceModelServiceGroundingprovidespresents(what it does)describedby(how it works)supports(how to access)服务模型服务模型2008-2010byLiWeigang.Allrightsreserved.lServiceProcessDescribeshowaserviceworks:internalprocessesoftheserviceSpecifiesserviceinteractionprotocolSpecifiesabstractmessages:ontologicaltypeofinformationtransmittedlFacilitates(automated)Webserviceinvocationcompositioninteroperationmonitoring服务模型：描述方法服务模型：描述方法2008-2010byLiWeigang.Allrightsreserved.lThebasicclassoftheProcessOntologyistheProcess.lItssubclassesdescribeeachprocessby:anynumberof(possibly,conditional)inputs;anynumberof(possibly,conditional)outputs;anynumberofpreconditions,whichmustholdinorderfortheprocesstobeinvoked;anynumberof(possibly,conditional)sideeffects;anynumberofparticipants(subprocess)服务模型：过程本体服务模型：过程本体2008-2010byLiWeigang.Allrightsreserved.lAtomicprocesses:directlyinvokable(byanagent),havenosubprocesses,executedinasinglesteplCompositeprocesses:consistofother(non-compositeorcomposite)processesTheyhaveacomposedOfproperty,bywhichthecontrolstructureoftheprocessisindicated,usingaControlConstruct subclasses(seetable)lSimpleprocesses:abstractconcepts,usedtoprovideaviewofsomeatomicprocess,orasimplifiedrepresentationofsomecompositeprocess(i.e.,the“blackbox”viewofacollapsedcompositeprocess)服务模型：服务模型：OWL-S中的过程类型中的过程类型2008-2010byLiWeigang.Allrightsreserved.服务模型：总体结构服务模型：总体结构2008-2010byLiWeigang.Allrightsreserved.ConstructDescriptionSequenceExecutealistofprocessesinasequentialorderConcurrentExecuteelementsofabagofprocessesconcurrentlySplitInvokeelementsofabagofprocessesSplit+JoinInvokeelementsofabagofprocessesandsynchronizeUnorderedExecuteallprocessesinabaginanyorderChoiceChoosebetweenalternativesandexecuteoneIf-then-elseIfspecifiedconditionhold,execute“Then”,elseexecute“Else”.Repeat-UntilIterateexecutionofabagofprocessesuntilaconditionholdsRepeat-WhileIterateexecutionofabagofprocesseswhileaconditionholds服务模型：过程中的控制结构服务模型：过程中的控制结构2008-2010byLiWeigang.Allrightsreserved.GetDesiredFlightDetailsAirportFlightDateAtomicProcessdepartureAirport_InoutboundDate_InAtomicProcessExample2008-2010byLiWeigang.Allrightsreserved.AtomicProcessExample2008-2010byLiWeigang.Allrightsreserved.Composite ProcessConfirm ReservationBookFlightGet Contact DetailsSequenceGet Flight DetailsReserve FlightSequenceSequenceCompositeProcessExample2008-2010byLiWeigang.Allrightsreserved.ResourceServiceServiceProfileServiceModelServiceGroundingprovidespresents(what it does)describedby(how it works)supports(how to access)服务基点服务基点2008-2010byLiWeigang.Allrightsreserved.lServiceGroundingProvidesaspecificationofserviceaccessinformationServiceModel+GroundinggiveeverythingneededforusingtheserviceBuildsuponWSDL todefinemessagestructureandphysicalbindinglayerlSpecifies:communicationprotocols,transportmechanisms,agentcommunicationlanguages,etc.服务基点服务基点2008-2010byLiWeigang.Allrightsreserved.Resources/ConceptsWSDLOWL-SProcessModelAtomicProcessOperationMessageInputs/OutputsBindingtoSOAP,HTTP,etc.OWL-S/WSDLBinding2008-2010byLiWeigang.Allrightsreserved.OWL-S/WSDLBinding2008-2010byLiWeigang.Allrightsreserved.总结总结lSomesuperficialcommentsOWL-SitselfisanOWLOntology,CombinedwithSWRLforpreconditionsandeffects.Inputs/OutputssubclassesofSWRLvariablesPossiblecandidatesforlogicicallanguageused:SWRL,SWRL-FOL,(KIF,DRS)However:Dicsovery,compositionapproachespublishedsofaroperatepurelyondescriptionlogicreasoning2008-2010byLiWeigang.Allrightsreserved.思考与讨论题思考与讨论题1.Web服务为何引入语义？2.什么是本体，本体的要点及其构成？3.RDF与OWL有何关系？4.OWL-S的结构5.OWL-S如何与WSDL绑定？