semantics web research

1、DynamicDiscoveryofComplexConstraintbasedSemanticWebServicesLeDuyNganDataMiningDepartmentI2RASTARSingapeLimYuanJieTemasekPolytechnicSingapeyuanjie91@RajaramanKanagasabaiDataMiningDepartmentI2RASTARSingapestract—Webservice

2、discoveryistheprocessoffindingwebserviceprovidersthatsatisfyspecificservicerequesterrequirements.Inreallifescenariosservicesareoftendescribedwithcomplexconstraintscontaindynamicaspectsthatarenotadequatelysupptedbymostoft

3、hecurrentdiscoverysystems.InthispaperweproposeanovelOWLSbasedsemanticservicediscoverysystemfdynamicallydiscoveringcomplexconstraintbasedservices.TheproposedsystemisbasedonrepresentingcomplexserviceconstraintsasSemanticWe

4、bRuleLanguage(SWRL)rulesusingaruleenginefmatchmakinghlingdynamismviaarealtimeontologypopulationreasoninginfrastructure.WeconsidertheSemanticWebService(SWS)Challengeshippingdiscoveryscenarioshowwithdetailedillustrationtha

5、toursystemisabletosolveallthefiveservicecomplexitylevelssuccessfully.KeywdswebservicediscoverysemanticwebservicessemanticservicematchmakingontologiessemanticrulesI.INTRODUCTIONAWebserviceisasoftwarecomponentrepresentinga

6、servicewhichisabusinessoperationataskanactivity.IthasbecomeakeytechnologyintheWebasitenablestheinteroperationofheterogeneoussystemsthereuseofdistributedfunctionsinapplications.Astardserviceientedecosystemiscomprisedofser

7、viceprovidersofferingWebservicesservicerequestersdescribingrequirementsindertolocateservices.InsuchanecosystempublishingbindingdiscoveringWebservicesarethreeimptanttasks.Amongthemdiscoveringservicesisafundamentaltaskthat

8、involvestheprocessoffindingwebserviceswhichsatisfyspecificrequirements.CurrentWebservicesbasedonWebServiceDeionLanguage(WSDL)[1]employnaivesyntacticrepresentationstodescribetheservices.Thisleadstoalackofsemanticunderstin

9、gthatpreventsfullyautomaticdiscoverycompositioninteroperability.TowardsaddressingthisSemanticWebService(SWS)fmalisms[2]thatexploitSemanticWebTechnologies[3]havebeenproposedtofacilitaterichfmalrepresentationsofservices.Se

10、veralsemanticWebservicedeionlanguagessuchasOWLS[4]WSMO[5]SAWSDL[6]etc.havebeendeveloped.SemanticWebServicediscoveryleveragesontheSWSfmalismstosearchfserviceproviderssatisfyingaservicerequestersrequirement[10].OWLSMX[7]TU

11、B[8]MOD[9]areexamplesofsuchsystems.Howevermostofthesediscoverysystemssupptservicematchingmainlybasedontheinputparametersrequiredtoexecutetheservicetheserviceoutputthatrepresentstheresultsoftheexecution.Thislimitationispa

12、rtlycausedbythecurrentdeionlanguagese.g.OWLSthathavelimitedsupptfdescribingfunctionalnonfunctionalproperties.Theyareoftennotexpressiveenoughtosupptadvancedservicedeionsthatinvolvecomplexconstraintsthatarecommoninrealwlda

13、pplications[10].Fexampleconsiderashippingscenariowhereashippingprovideroffersaservicetoshipapackagefromoneplacetoanotherplace.Theserviceprovidermayhaveseveralconstraintsonitsserviceasfollows:(1)ShipstoAfricaNthAmericaEur

14、opeAsia(2)Onlypackagesweighing50lbslessareshipped(3)Ifthecollectedtimeisbefe6pmthentheshippingdurationwillbelessthanaday.Ofthesethefirstconstraintcanbedescribedinthestardontologymodelingtheservices.Howeverthisisnottrueft

15、hesecondthethirdconstraintsasthecurrentontologylanguageshavelimitedsupptfsuchcomplexconstraints.Similarlytheservicerequestermayhavesimilarsophisticatedconstraintsintherequests.Towardsmodelingrealwldscenarioswearguethatit

16、isimptanttosupptsuchconstraintdeionsincurrentdeionlanguages.OnanotherdirectionthesemanticdeionofsomeadvertisedWebservicesmaycompletelybeavailableonlybyinvocation.Thismaybethecaseiffexampleitturnsouttobeimpracticaltoprovi

17、deanexhaustivesemanticdeionofthecapabilitiesoffered.Itisdesirablethatthewebservicediscoverysystemsupptsmatchingofserviceprovidersrequestersdynamically.WSMObasedwksthatsupptcomplexconstraintshavebeenreptedintheliterature[

18、1112]butsystemsbasedonOWLSareafew.ThispaperaimstoinvestigateifdynamicdiscoveryofcomplexwebservicesisfeasiblewithOWLSrelatedW3Ctechnologiesalone.WeproposeanovelOWLSbasedsemanticservicediscoverysystemfdynamicallydiscoverin

19、gcomplexconstraintbasedservices.Anovelservicematchmakingmethodisproposedwhen2011FifthIEEEInternationalConferenceonSemanticComputing978076954492211$26.00?2011IEEEDOI10.1109ICSC.2011.3851Thenextsectionpresentsourmethodfdis

20、coveringservicesaccdingtoDefinition2.III.SEMANTICRULEBASEDDYNAMICDISCOVERYSYSTEMA.SupptingConstraintsinOWLSOWLSisaservicedeionfmalismhasstrongsupptfromtheresearchindustrycommunities[15].Itcomprisesthreemainparts:ServiceP

21、rofilewhichisfadvertisingdiscoveringservicecapabilitiesServiceModelwhichgivesadetaileddeionofaservicesoperationServiceGroundingwhichprovidesdetailsonhowtointeroperatewithaserviceviamessages.GenerallyspeakingOWLSServicePr

22、ofileprovidesboththefunctionalnonfunctionalinfmationneededfanagenttodiscoveraservicewhileOWLSServiceModelOWLSServiceGroundingtakentogetherprovideenoughinfmationfanagenttomakeuseofaserviceoncefound.OWLSprovidesagenericway

23、ofrepresentingconditionexpressions2inWebservices.ItsupptssixlanguageslogicsincludingSWRLSWRLFOLDRSKIFSPARQLRDQLcanbeeasilyextendedtosupptotherlogicexpressions.HoweverreasoningsupptoverlogicexpressionsembeddedinOWLSislimi

24、ted.Inthispaperwetakeadifferentapproachwherebywemodelthepreconditionspostconditionsasconstraintsinthedomainontology.AsproofofconceptweadoptSWRL[16]tomodeltheconstraints.SWRLisaproposalfaSemanticWebrulelanguagecombiningsu

25、blanguagesoftheOWLWebOntologyLanguage(OWLDLLite)withthoseoftheRuleMarkupLanguage.TherefeSWRLusesOWLaxiomsenablesHnlikerulestobecombinedwithanOWLknowledgebase.SWRLrulesarewrittenaspairsofantecedent(head)consequent(body)bo

26、thexpressedasaconjunctionofonemeatoms.Aruleexpressesthefollowingmeaning:whenevertheconditionsspecifiedintheantecedentholdthentheconditionsspecifiedintheconsequentmustalsohold.Ruleswithdisjunctiveantecedentscanbeequivalen

27、tlyrewrittenasmultipleruleseachcrespondingtoadisjunct.Similarlyruleswithconjunctiveconsequentscouldbechangedintomultipleruleseachwithanatomicconsequent.ThusSWRLrulesgiveadditionalexpressivitybutattheexpenseofdecidability

28、.InthispaperweconsiderasubsetofSWRLwherethevariablesbindonlytoknowninstancesinanontologybutmaycontainbuiltins.ThesyntaxfSWRLextendstheabstractsyntaxofOWL.Aruleinthissyntaxhasthefm:“antecedentconsequent“wherebothanteceden

29、tconsequentareconjunctionsofatomswrittena1...an.Variablesareindicatedusingthestardconventionofprefixingthemwithaquestionmark(e.g.x)[17].Usingthissyntaxaruleassertingthatthecompositionofparentbrother2:www.ai.damlserviceso

30、wls1.2genericExpression.owlpropertiesimpliestheunclepropertywouldbewrittenas:“parent(xy)^brother(yz)uncle(xz)“.IfBillhasJobasaparentJobhasDavidhasabrotherthenthisrulerequiresthatBillhasDavidasanuncle.Figure1.ASWRLexample

31、SWRLrulesreasonaboutOWLindividualsprimarilyintermsofOWLclassesproperties.FexampleaSWRLruleexpressingthatiftheshippingrequesterexpectstoshipapackagetotheshippingproviderresidinginthesamecountrythentheprovidercansatisfythe

32、requesterisdepictedinFigure1.IntuitivelytheconceptofShippingServiceRequesterShippingServiceProvidercanbecapturedusinganOWLclassshipToisapropertyoftheontology.ExecutingthisrulewouldhavetheeffectofsettingtheShippingProvide

33、rMatchedpropertytoProviderintheindividualthatsatisfiestherulenamedRequester.JessisaruleengineingenvironmentftheJavaplatfm3.Jessissmalllightoneofthefastestruleenginesavailable.Jesshasmanyuniquefeaturesincludingbackwardsch

34、ainingwkingmemyqueriesJesscandirectlymanipulatereasonaboutJavaobjects.OurSWRLrulesareexecutedusingJess.SQWRL[18]isbasedontheSWRLrulelanguageusesSWRLsemanticfoundationasitsfmalunderpinning.ItoffersawaytoallowOWLontologies

35、tobequeried.Italsoprovidesasetofoperatstoperfmclosureoperationstoallowlimitedfmsofnegationasfailurecountingaggregation.B.DynamismfDiscoveryOurapproachusesaninhousesemantictechnologyinfrastructurepoweredbyAllegroGraph44to

36、processtheontologyperfmpopulation&reasoningbefeinvokingthematchmaking.Thestrategyfhlingdynamismisasfollows.Givenaservicerequestfirstanontologyloaderreadsuptheserviceoffersinthereposity.EachserviceoffermayhaveWSDLendpoint

37、scontainingmethodsthatcanbeinvokedonlyduringruntime(e.g.shippingratecomputation).TheneededWSDLmethodsareinvokedbasedontheservicespecificationstheresultsareaddedtotheontologywiththeOntologyPopulationengine.Thematchmakerma