服务计算基础之语义服务

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当前第1页\共有65页\编于星期五\1点第九章语义Web服务当前第2页\共有65页\编于星期五\1点主要内容概述语义网语义Web服务当前第3页\共有65页\编于星期五\1点第一节概述当前第4页\共有65页\编于星期五\1点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。语义和语义网当前第5页\共有65页\编于星期五\1点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服务当前第6页\共有65页\编于星期五\1点语义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服务当前第7页\共有65页\编于星期五\1点第二节语义网当前第8页\共有65页\编于星期五\1点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.”当前第9页\共有65页\编于星期五\1点TheSemanticWebisanextensionofthecurrentwebinwhichinformationisgivenwell-definedmeaning,betterenablingcomputersandpeopletoworkinco-operation.

–TimBerners-Lee,JamesHendler,OraLassila,TheSemanticWeb,ScientificAmerican,May2001SemanticWeb的定义当前第10页\共有65页\编于星期五\1点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!当前第11页\共有65页\编于星期五\1点本体(ontology)aphilosophicaldiscipline,branchofphilosophythatdealwiththenatureandtheorganizationofreality.Scienceofbeing

Triestoanswerthequestions:whatisbeing?whatarethefeaturescommontoallbeings?本体(ontology)的定义当前第12页\共有65页\编于星期五\1点

Ontologyisaformal,explicitspecificationofasharedconceptualization–Gruber要点：Conceptualization:anabstractmodelofphenomenaintheworldbyhavingidentifiedtherelevantconceptsofthosephenomena.Explicit:thetypeofconceptsused,andtheconstraintsontheiruseareexplicitlydefined.Formal:thefactthattheontologyshouldbemachinereadable.Shared:ontologyshouldcaptureconsensualknowledgeacceptedbythecommunities

本体(ontology)的定义当前第13页\共有65页\编于星期五\1点Whatisaconcept?

Differentcommunitieshavedifferentnotionsonwhataconceptmeans:

formalconcepts

conceptlabel

terminology

frameorOOThereism:nrelationshipbetweenwordsandconceptsdifferentwordsmayrefertothesameconceptsawordmayrefertoseveralconcepts

Ontologylanguagesshouldprovidemeansformakingthisdifferenceexplicit

本体(ontology)的定义当前第14页\共有65页\编于星期五\1点Classesconceptsofthedomainortasks,whichareusuallyorganizedintaxonomiesinuniv-ontology:studentandprofessoraretwoclassesRelationsatypeofinteractionbetweenconceptsofthedomainsuchas:subclass-of,is-a本体的构成当前第15页\共有65页\编于星期五\1点FunctionsAspecialcaseofrelationsinwhichthen-thelementoftherelationshipisuniqueforthen-1precedingelementsSuchas:Price-of-a-used-carcandefinethecalculationofthepriceofthesecond-handcaronthecar-model,manufacturingdataandkilometersAxioms（公理）ModelsentencesthatarealwaystrueSuchas:ifthestudentattendsbothAandBcourse,thenheorshemustbeasecondyearstudent本体的构成当前第16页\共有65页\编于星期五\1点Instancesrepresentspecificelementssuchas:StudentcalledPeterisaninstanceofStudentclass本体的构成当前第17页\共有65页\编于星期五\1点RDFdatamodelResourcesAresourceisathingyoutalkabout(canreference)ResourceshaveURI’s(UniformResourceIdentifiers)RDFdefinitionsarethemselvesResourcesPropertiesAspecialkindofresources,describerelationsbetweenresources.(subject,predicate,object)资源描述框架(RDF)当前第18页\共有65页\编于星期五\1点<rdf:RDFxmlns:rdf="/1999/02/22-rdf-syntax-ns#"xmlns:uni="/2005/lesson-uni"> <rdf:Descriptionrdf:about="CIT1111"> <uni:courseName>DiscreteMathematics</uni:courseName> <uni:isTaughtBy> <rdf:Descriptionrdf:about="949318"> <uni:name>DavidBillington</uni:name> <uni:title>AssociateProfessor</uni:title> </rdf:Description> </uni:isTaughtBy> </rdf:Description></rdf:RDF>RDF当前第19页\共有65页\编于星期五\1点Classesandproperties classes:asetofobjects,rdfs:Class instances:individualobject property:addrestrictionsonobjects,rdfs:PropertyClassandhierarchies资源描述框架模式(RDFS)当前第20页\共有65页\编于星期五\1点

Restrictions:CoursesmusttaughtbyacademicstaffmembersonlyMichaelMaherisaprofessorifweknow,professorisasubclassofacademicstaffMichaelMaherisallowedtoteachcoursesPropertyhierarchies

资源描述框架模式(RDFS)当前第21页\共有65页\编于星期五\1点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)当前第22页\共有65页\编于星期五\1点RDF和RDFS的关系当前第23页\共有65页\编于星期五\1点RDF/RDFSlimitationsLocalscopeofproperties.

cowseatonlyplantsDisjointnessofclasses.MaleandfemaleBooleancombinationsofclasses.(∪,∩,～

)Cardinalityrestrictions,propertyvaluerestriction.personandparents,teacherandcoursesSpecialcharacteristicsofpropertiesSuperviseandIsSupervisedbyRDF的局限性当前第24页\共有65页\编于星期五\1点Requirementsforontologylanguageawell-definedsyntaxaformalsemantics(convenienttoreason)convenienceofexpressionefficientreasoningsupportsufficientexpressivepower本体描述语言OWL当前第25页\共有65页\编于星期五\1点OWLisbuiltontopofRDFOWLisforprocessinginformationonthewebOWLwasdesignedtobeinterpretedbycomputersOWLwasnotdesignedforbeingreadbypeopleOWLiswritteninXMLOWLisawebstandard什么是OWL当前第26页\共有65页\编于星期五\1点OriginsofOWLDAMLDAML+OILDAML=DARPAAgentMarkupLanguageOIL=OntologyInferenceLayerOWLisnowaW3CRecommendation!OILOWLRDFAllwereinfluencedbyRDFOWL当前第27页\共有65页\编于星期五\1点LogicfoundationofOWL:DescriptionLanguageOWLLite:ClassificationhierarchySimpleconstraintsOWLDL(DescriptionLogic):MaximalexpressivenessWhilemaintainingtractabilityStandardformalisationOWLFull:VeryhighexpressivenessLoosingtractabilityNon-standardformalisationAllsyntacticfreedomofRDF

(self-modifying)SyntacticlayeringSemanticlayeringFullDLLiteLayeredlanguageofOWL当前第28页\共有65页\编于星期五\1点OWL当前第29页\共有65页\编于星期五\1点OWL当前第30页\共有65页\编于星期五\1点OWL当前第31页\共有65页\编于星期五\1点<?xmlversion="1.0"?><rdf:RDFxmlns:rdf="/1999/02/22-rdf-syntax-ns#"xmlns:rdfs="/2000/01/rdf-schema#"xmlns:owl="/2002/07/owl#"xmlns:dc="/dc/elements/1.1/"xml:base="http://wasp.cs.vu.nl/sekt/ontology/animal"><owl:Ontologyrdf:about=“animal"/><owl:Classrdf:ID="Eagle"><rdfs:subClassOf><owl:Classrdf:about="#Bird"/></rdfs:subClassOf></owl:Class><owl:Classrdf:ID="Animal"/><owl:Classrdf:ID="Fly"><owl:disjointWith><owl:Classrdf:about="#Penguin"/></owl:disjointWith><rdfs:subClassOfrdf:resource="#Animal"/></owl:Class><owl:Classrdf:ID="Bird"><rdfs:subClassOfrdf:resource="#Fly"/></owl:Class><owl:Classrdf:ID="Penguin"><rdfs:subClassOfrdf:resource="#Bird"/><owl:disjointWithrdf:resource="#Fly"/></owl:Class></rdf:RDF>OWLExample:animals当前第32页\共有65页\编于星期五\1点第三节语义Web服务当前第33页\共有65页\编于星期五\1点WWWURI,HTML,HTTPBringingthewebtoitsfullpotentialSemanticWebRDF,RDF(S),OWLDynamicWebServicesUDDI,WSDL,SOAPStaticSemanticWebServicesMotivationofSemanticWebService当前第34页\共有65页\编于星期五\1点

SemanticWebTechnology+WebServiceTechnologySemanticWebServices=SemanticWebServices

allowmachinesupporteddatainterpretationontologiesasdatamodelautomateddiscovery,selection,composition,andweb-basedexecutionofservicesasintegratedsolutionforrealizingthevisionofthenextgenerationoftheWeb.当前第35页\共有65页\编于星期五\1点SemanticWebServicesDefineexhaustivedescriptionframeworksfordescribingWebServicesandrelatedaspects(WebServiceDescriptionOntologies)Supportontologiesasunderlyingdatamodeltoallowmachinesupporteddatainterpretation(SemanticWebaspect)DefinesemanticallydriventechnologiesforautomationoftheWebServiceusageprocess(WebServiceaspect)

当前第36页\共有65页\编于星期五\1点SemanticWebServicesUsageProcess:Publication:MaketheavailabledescriptionofthecapabilityofaserviceDiscovery:LocatedifferentservicessuitableforagiventaskSelection:ChoosethemostappropriateservicesamongtheavailableonesComposition:CombineservicestoachieveagoalMediation:Solvemismatches(data,protocol,process)amongthecombinedExecution:Invokeservicesfollowingprogrammaticconventions

当前第37页\共有65页\编于星期五\1点SemanticWebServicesExecutionsupport:Monitoring:ControltheexecutionprocessCompensation:ProvidetransactionalsupportandundoormitigateunwantedeffectsReplacement:FacilitatethesubstitutionofservicesbyequivalentonesAuditing:Verifythatserviceexecutionoccurredintheexpectedway当前第38页\共有65页\编于星期五\1点SemanticWebServicesWithSemantic:Notonlyaninterfacedescription,butalsothecapabilityoftheservice.Logicreasoningenhancedservicediscoveryandcomposition.Canbedoneautomatically.当前第39页\共有65页\编于星期五\1点OWL-S:OntologyWebLanguageforServicesWSMLWSDL-S…语义Web服务标记语言当前第40页\共有65页\编于星期五\1点OntologyOWL-SisanOWLontologytodescribeWebservicesOWL-SleveragesonOWLtoSupportcapabilitybaseddiscoveryofWebservicesSupportautomaticcompositionofWebServicesSupportautomaticinvocationofWebservices"Completedonotcompete"OWL-SdoesnotaimtoreplacetheWebservicesstandards ratherOWL-SattemptstoprovideasemanticlayerOWL-SreliesonWSDLforWebserviceinvocation(seeGrounding)OWL-sExpandsUDDIforWebservicediscovery(OWL-S/UDDImapping)OWL-S概述当前第41页\共有65页\编于星期五\1点OWL-S整体结构ResourceServiceService

ProfileService

ModelService

Groundingcommunicationprotocol(RPC,HTTP,…)portnumbermarshalling/serializationinputtypesoutputtypespreconditionseffectsprocessflowcompositionhierarchyprocessdefinitionsprovidespresents(whatitdoes)describedby

(howitworks)

supports

(howtoaccess)当前第42页\共有65页\编于星期五\1点服务概要ResourceServiceService

ProfileService

ModelService

Groundingprovidespresents(whatitdoes)describedby

(howitworks)

supports

(howtoaccess)当前第43页\共有65页\编于星期五\1点服务概要

ServiceProfilePresentedbyaservice.RepresentswhattheserviceprovidesTwomainuses:AdvertisementsofWebServicescapabilities(non-functionalproperties,QoS,Description,classification,etc.)RequestofWebserviceswithagivensetofcapabilitiesProfiledoesnotspecifyuse/invocation!当前第44页\共有65页\编于星期五\1点NonFunctionalPropertiesFunctionalityDescription服务概要当前第45页\共有65页\编于星期五\1点SummarizestheabstractcapabilityofaserviceFunctionalspecificationof

whattheserviceprovides

intermsofparameters,

subclassedas:preconditionsinputsoutputseffects服务概要—功能性描述当前第46页\共有65页\编于星期五\1点PreconditionsSetofconditionsthatshouldholdpriortoserviceinvocationInputsSetofnecessaryinputsthattherequestershouldprovidetoinvoketheserviceOutputsResultsthattherequestershouldexpectafterinteractionwiththeserviceprovideriscompletedEffectsSetofstatementsthatshouldholdtrueiftheserviceisinvokedsuccessfullyOftenrefertoreal-worldeffectsPackagebeingdelivered,orCreditcardbeingdebited服务概要—功能性描述：参数当前第47页\共有65页\编于星期五\1点ProvidessupportinginformationabouttheserviceTheseincludeserviceNametextDescriptionhas_processqualityRatingserviceParameterserviceCategorycontactInformation服务概要—非功能性描述当前第48页\共有65页\编于星期五\1点Sub-classingtheProfilemodelfacilitatesthecreationandspecialisationofservicecategoriesEachsubclasscan:IntroducenewpropertiesPlacerestrictionsonexistingpropertiesSub-classingcanalsobeusedtospecialiserequestsforserviceAnexampleProfileHierarchyisprovided,butotherscouldjustaseasilybedefined服务概要层次当前第49页\共有65页\编于星期五\1点服务概要层次：例子当前第50页\共有65页\编于星期五\1点ResourceServiceService

ProfileService

ModelService

Groundingprovidespresents(whatitdoes)describedby

(howitworks)

supports

(howtoaccess)服务模型当前第51页\共有65页\编于星期五\1点ServiceProcessDescribeshowaserviceworks:internalprocessesoftheserviceSpecifiesserviceinteractionprotocolSpecifiesabstractmessages:ontologicaltypeofinformationtransmittedFacilitates(automated)Webserviceinvocationcompositioninteroperationmonitoring服务模型：描述方法当前第52页\共有65页\编于星期五\1点ThebasicclassoftheProcessOntologyistheProcess.Itssubclassesdescribeeachprocessby:anynumberof(possibly,conditional)inputs;anynumberof(possibly,conditional)outputs;anynumberofpreconditions,whichmustholdinorderfortheprocesstobeinvoked;anynumberof(possibly,conditional)sideeffects;anynumberofparticipants(subprocess)服务模型：过程本体当前第53页\共有65页\编于星期五\1点Atomicprocesses:directlyinvokable(byanagent),havenosubprocesses,executedinasinglestepCompositeprocesses:consistofother(non-compositeorcomposite)processes

TheyhaveacomposedOfproperty,bywhichthecontrolstructureoftheprocessisindicated,usingaControlConstruct

subclasses(seetable…)Simpleprocesses:abstractconcepts,usedtoprovideaviewofsomeatomicprocess,orasimplifiedrepresentationofsomecompositeprocess(i.e.,the“blackbox”viewofacollapsedcompositeprocess)服务模型：OWL-S中的过程类型当前第54页\共有65页\编于星期五\1点服务模型：总体结构当前第55页\共有65页\编于星期五\1点ConstructDescriptionSequenceExecutealistofprocessesinasequentialorderConcurrentExecuteelementsofabagofprocessesconcurrentlySplitInvokeelementsofabagofprocessesSplit+JoinInvokeelementsofabagofprocessesandsynchronizeUnorderedExecuteallprocessesinabaginanyorderChoiceChoosebetweenalternativesandexecuteoneIf-then-elseIfspecifiedconditionhold,execute“Then”,elseexecute“Else”.Repeat-UntilIterateexecutionofabagofprocessesuntilaconditionholdsRepeat-WhileIterateexecutionofabagofprocesseswhileaconditionholds服务模型：过程中的控制结构当前第56页\共有65页\编于星期五\1点<!–AtomicProcessDefinition-GetDesiredFlightDetails

--><rdfs:Classrdf:ID=“GetDesiredFlightDetails”> <rdfs:subClassOf

rdf:resource= “/Process#AtomicProcess”/></rdfs:Class>GetDesiredFlightDetailsAirportFlightDateAtomicProcessdepartureAirport_InoutboundDate_InAtomicProcessExample当前第57页\共有65页\编于星期五\1点<!–(sample)Inputsusedbyatomicprocess

GetDesiredFlightDetails--><rdf:Propertyrdf:ID="departureAirport_In">

<rdfs:subPropertyOf

rdf:resource= "http:///Process#input"/> <rdfs:domain

rdf:resource="#GetDesiredFlightDetails"/> <rdfs:range

rdf:resource=" DAML-S/concepts.daml#Airport"/></rdf:Property><rdf:Propertyrdf:ID="outbounDate_In">

<rdfs:subPropertyOf

rdf:resource="http:///Process#input"/><rdfs:domain

rdf:resource="#GetDesiredFlightDetails"/>

<rdfs:range

rdf:resource="DAML-S/concepts.daml#FlightDate"/></rdf:Property>AtomicProcessExample当前第58页\共有65页\编于星期五\1点<rdfs:Classrdf:ID="BookFlight"><rdfs:subClassOf

rdf:resource="#CompositeProcess"/><rdfs:subClassOf

rdf:resource="/Process#Sequence"/><daml:subClassOf><daml:Restriction><daml:onProperty

rdf:resource="/Process#components"/><daml:toClass><daml:subClassOf><daml:unionOfrdf:parseType="daml:collect