服务计算基础(语义Web服务).ppt

服务计算基础 主讲 李伟刚liweigang 西北工业大学软件与微电子学院 第九章语义Web服务 主要内容 概述语义网语义Web服务 第一节概述 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 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 Web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 WSDL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 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 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Web服务 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 语义Web和Web服务是语义Web服务的两大支撑技术 OWL 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Web服务 第二节语义网 SemanticWeb的由来 Webwas invented byTimBerners Lee aphysicistworkingatCERNTBL soriginalvisionoftheWebwasmuchmoreambitiousthantherealityoftheexisting syntactic Web TBL andothers havesincebeenworkingtowardsrealisingthisvision whichhasbecomeknownastheSemanticWebE g articleinMay2001issueofScientificAmerican agoaloftheWebwasthat iftheinteractionbetweenpersonandhypertextcouldbesointuitivethatthemachine readableinformationspacegaveanaccuraterepresentationofthestateofpeople sthoughts interactions andworkpatterns thenmachineanalysiscouldbecomeaverypowerfulmanagementtool seeingpatternsinourworkandfacilitatingourworkingtogetherthroughthetypicalproblemswhichbesetthemanagementoflargeorganizations TheSemanticWebisanextensionofthecurrentwebinwhichinformationisgivenwell definedmeaning betterenablingcomputersandpeopletoworkinco operation TimBerners Lee JamesHendler OraLassila TheSemanticWeb ScientificAmerican May2001 SemanticWeb的定义 SemanticWeb的架构的相关标准 本体层1 以谓词演算为基础的语言KIF basedOntolingua CycL Loom Frame Logic2 基于XML的本体表示语言SHOE XOL OML CKML RDFS Riboweb OIL DAML OIL OWL 规则层RuleML HornML DLML 逻辑框架层FOL HOL DL Horn logic OMDoc 下四层已经发展的比较成熟与完善 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 Wearehere 本体 ontology aphilosophicaldiscipline branchofphilosophythatdealwiththenatureandtheorganizationofreality ScienceofbeingTriestoanswerthequestions whatisbeing whatarethefeaturescommontoallbeings 本体 ontology 的定义 Ontologyisaformal explicitspecificationofasharedconceptualization Gruber要点 Conceptualization anabstractmodelofphenomenaintheworldbyhavingidentifiedtherelevantconceptsofthosephenomena Explicit thetypeofconceptsused andtheconstraintsontheiruseareexplicitlydefined Formal thefactthattheontologyshouldbemachinereadable Shared ontologyshouldcaptureconsensualknowledgeacceptedbythecommunities 本体 ontology 的定义 Whatisaconcept Differentcommunitieshavedifferentnotionsonwhataconceptmeans formalconceptsconceptlabelterminologyframeorOOThereism nrelationshipbetweenwordsandconceptsdifferentwordsmayrefertothesameconceptsawordmayrefertoseveralconceptsOntologylanguagesshouldprovidemeansformakingthisdifferenceexplicit 本体 ontology 的定义 Classesconceptsofthedomainortasks whichareusuallyorganizedintaxonomiesinuniv ontology studentandprofessoraretwoclassesRelationsatypeofinteractionbetweenconceptsofthedomainsuchas subclass of is a 本体的构成 FunctionsAspecialcaseofrelationsinwhichthen thelementoftherelationshipisuniqueforthen 1precedingelementsSuchas Price of a used carcandefinethecalculationofthepriceofthesecond handcaronthecar model manufacturingdataandkilometersAxioms 公理 ModelsentencesthatarealwaystrueSuchas ifthestudentattendsbothAandBcourse thenheorshemustbeasecondyearstudent 本体的构成 Instancesrepresentspecificelementssuchas StudentcalledPeterisaninstanceofStudentclass 本体的构成 RDFdatamodelResourcesAresourceisathingyoutalkabout canreference ResourceshaveURI s UniformResourceIdentifiers RDFdefinitionsarethemselvesResourcesPropertiesAspecialkindofresources describerelationsbetweenresources subject predicate object 资源描述框架 RDF DiscreteMathematicsDavidBillingtonAssociateProfessor RDF Classesandpropertiesclasses asetofobjects rdfs Classinstances individualobjectproperty addrestrictionsonobjects rdfs PropertyClassandhierarchies 资源描述框架模式 RDFS Restrictions CoursesmusttaughtbyacademicstaffmembersonlyMichaelMaherisaprofessorifweknow professorisasubclassofacademicstaffMichaelMaherisallowedtoteachcoursesPropertyhierarchies 资源描述框架模式 RDFS SomeimportantterminologiesinRDFSrdf 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 RDFS RDF和RDFS的关系 RDF RDFSlimitationsLocalscopeofproperties cowseatonlyplantsDisjointnessofclasses MaleandfemaleBooleancombinationsofclasses Cardinalityrestrictions propertyvaluerestriction personandparents teacherandcoursesSpecialcharacteristicsofpropertiesSuperviseandIsSupervisedby RDF的局限性 Requirementsforontologylanguageawell definedsyntaxaformalsemantics convenienttoreason convenienceofexpressionefficientreasoningsupportsufficientexpressivepower 本体描述语言OWL OWLisbuiltontopofRDFOWLisforprocessinginformationonthewebOWLwasdesignedtobeinterpretedbycomputersOWLwasnotdesignedforbeingreadbypeopleOWLiswritteninXMLOWLisawebstandard 什么是OWL OriginsofOWL DAML DAML OIL DAML DARPAAgentMarkupLanguageOIL OntologyInferenceLayer OWLisnowaW3CRecommendation OIL OWL RDF AllwereinfluencedbyRDF OWL LogicfoundationofOWL DescriptionLanguageOWLLite ClassificationhierarchySimpleconstraintsOWLDL DescriptionLogic MaximalexpressivenessWhilemaintainingtractabilityStandardformalisationOWLFull VeryhighexpressivenessLoosingtractabilityNon standardformalisationAllsyntacticfreedomofRDF self modifying SyntacticlayeringSemanticlayering Full DL Lite LayeredlanguageofOWL OWL OWL OWL OWLExample animals 第三节语义Web服务 WWWURI HTML HTTP Bringingthewebtoitsfullpotential SemanticWebRDF RDF S OWL Dynamic WebServicesUDDI WSDL SOAP Static SemanticWebServices MotivationofSemanticWebService SemanticWebTechnology WebServiceTechnology SemanticWebServices SemanticWebServices allowmachinesupporteddatainterpretationontologiesasdatamodel automateddiscovery selection composition andweb basedexecutionofservices asintegratedsolutionforrealizingthevisionofthenextgenerationoftheWeb SemanticWebServices DefineexhaustivedescriptionframeworksfordescribingWebServicesandrelatedaspects WebServiceDescriptionOntologies Supportontologiesasunderlyingdatamodeltoallowmachinesupporteddatainterpretation SemanticWebaspect DefinesemanticallydriventechnologiesforautomationoftheWebServiceusageprocess WebServiceaspect SemanticWebServices UsageProcess Publication MaketheavailabledescriptionofthecapabilityofaserviceDiscovery LocatedifferentservicessuitableforagiventaskSelection ChoosethemostappropriateservicesamongtheavailableonesComposition CombineservicestoachieveagoalMediation Solvemismatches data protocol process amongthecombinedExecution Invokeservicesfollowingprogrammaticconventions SemanticWebServices Executionsupport Monitoring ControltheexecutionprocessCompensation ProvidetransactionalsupportandundoormitigateunwantedeffectsReplacement FacilitatethesubstitutionofservicesbyequivalentonesAuditing Verifythatserviceexecutionoccurredintheexpectedway SemanticWebServices WithSemantic Notonlyaninterfacedescription butalsothecapabilityoftheservice Logicreasoningenhancedservicediscoveryandcomposition Canbedoneautomatically OWL S OntologyWebLanguageforServicesWSMLWSDL S 语义Web服务标记语言 OntologyOWL SisanOWLontologytodescribeWebservicesOWL SleveragesonOWLtoSupportcapabilitybaseddiscoveryofWebservicesSupportautomaticcompositionofWebServicesSupportautomaticinvocationofWebservices Completedonotcompete OWL SdoesnotaimtoreplacetheWebservicesstandardsratherOWL SattemptstoprovideasemanticlayerOWL SreliesonWSDLforWebserviceinvocation seeGrounding OWL sExpandsUDDIforWebservicediscovery OWL S UDDImapping OWL S概述 OWL S整体结构 Resource Service ServiceProfile ServiceModel ServiceGrounding communicationprotocol RPC HTTP portnumbermarshalling serialization inputtypesoutputtypespreconditionseffects processflowcompositionhierarchyprocessdefinitions provides presents whatitdoes describedby howitworks supports howtoaccess 服务概要 Resource Service ServiceProfile ServiceModel ServiceGrounding provides presents whatitdoes describedby howitworks supports howtoaccess 服务概要 ServiceProfilePresentedbyaservice RepresentswhattheserviceprovidesTwomainuses AdvertisementsofWebServicescapabilities non functionalproperties QoS Description classification etc RequestofWebserviceswithagivensetofcapabilities Profiledoesnotspecifyuse invocation NonFunctionalProperties FunctionalityDescription 服务概要 SummarizestheabstractcapabilityofaserviceFunctionalspecificationofwhattheserviceprovidesintermsofparameters subclassedas preconditionsinputsoutputseffects 服务概要 功能性描述 PreconditionsSetofconditionsthatshouldholdpriortoserviceinvocationInputsSetofnecessaryinputsthattherequestershouldprovidetoinvoketheserviceOutputsResultsthattherequestershouldexpectafterinteractionwiththeserviceprovideriscompletedEffectsSetofstatementsthatshouldholdtrueiftheserviceisinvokedsuccessfullyOftenrefertoreal worldeffectsPackagebeingdelivered orCreditcardbeingdebited 服务概要 功能性描述 参数 ProvidessupportinginformationabouttheserviceTheseincludeserviceNametextDescriptionhas processqualityRatingserviceParameterserviceCategorycontactInformation 服务概要 非功能性描述 Sub classingtheProfilemodelfacilitatesthecreationandspecialisationofservicecategoriesEachsubclasscan IntroducenewpropertiesPlacerestrictionsonexistingpropertiesSub classingcanalsobeusedtospecialiserequestsforserviceAnexampleProfileHierarchyisprovided butotherscouldjustaseasilybedefined 服务概要层次 服务概要层次 例子 服务模型 ServiceProcessDescribeshowaserviceworks internalprocessesoftheserviceSpecifiesserviceinteractionprotocolSpecifiesabstractmessages ontologicaltypeofinformationtransmittedFacilitates automated Webserviceinvocationcompositioninteroperationmonitoring 服务模型 描述方法 ThebasicclassoftheProcessOntologyistheProcess Itssubclassesdescribeeachprocessby anynumberof possibly conditional inputs anynumberof possibly conditional outputs anynumberofpreconditions whichmustholdinorderfortheprocesstobeinvoked anynumberof possibly conditional sideeffects anynumberofparticipants subprocess 服务模型 过程本体 Atomicprocesses directlyinvokable byanagent havenosubprocesses executedinasinglestepCompositeprocesses consistofother non compositeorcomposite processesTheyhaveacomposedOfproperty bywhichthecontrolstructureoftheprocessisindicated usingaControlConstructsubclasses seetable Simpleprocesses abstractconcepts usedtoprovideaviewofsomeatomicprocess orasimplifiedrepresentationofsomecompositeprocess i e the blackbox viewo