Jena对本体推理的支持

1、Jena对本体推理的支持Jena2InferencesupportThissectionofthedocumentationdescribesthecurrentsupportforinferenceavailablewithinJena2.ItincludesanoutlineofthegeneralinferenceAPI,togetherwithdetailsofthespecificruleenginesandconfigurationsforRDFSandOWLinferencesuppliedwithJena2.NotallofthefinedetailsoftheAPIarecoveredhere:refertotheJena2JavadoctogetthefulldetailsofthecapabilitiesoftheAPI.Notethatthisisapreliminaryversionofthisdocument,someerrorsorinconsistenciesarepossible,andfeedbacktotheauthor(viathejena-d。

2、evsupportlist)iswelcomed.Index1.Overviewofinferencesupport2.TheinferenceAPI3.TheRDFSreasoner4.TheOWLreasoner5.DAMLsupport6.Thetransitivereasoner7.Thegeneralpurposeruleengine8.Extendingtheinferencesupport9.FuturesOverviewofinferencesupportTheJena2inferencesubsystemisdesignedtoallowarangeofinferenceenginesorreasonerstobepluggedintoJena.SuchenginesareusedtoderiveadditionalRDFassertionswhichareentailedfromsomebaseRDFtogetherwithanyoptionalontologyinformationandtheaxiomsandrulesassociatedwiththereaso。

3、ner.TheprimaryuseofthismechanismistosupporttheuseoflanguagessuchasRDFSandOWLwhichallowadditionalfactstobeinferredfrominstancedataandclassdescriptions.However,themachineryisdesignedtobequitegeneraland,inparticular,itincludesagenericruleenginethatcanbeusedformanyRDFprocessingortransformationtasks.Wewilltrytousetheterminferencetorefertotheabstractprocessofderivingadditionalinformationandthetermreasonertorefertoaspecificcodeobjectthatperformsthistask.Suchusageisarbitraryandifweslipintousingequivalen。

4、ttermslikereasoningandinferenceenginepleaseforgiveus.Theoverallstructureoftheinferencemachineryisillustratedbelow.ApplicationsnormallyaccesstheinferencemachinerybyusingtheModelFactorytoassociateadatasetwithsomereasonertocreateanewModel.Queriestothecreatedmodelwillreturnnotonlythosestatementsthatwerepresentintheoriginaldatabutalsoadditionalstatementsthancanbederivedfromthedatausingtherulesorotherinferencemechanismsimplementedbythereasoner.Asillustratedtheinferencemachineryisactuallyimplementedatt。

5、heleveloftheGraphSPI,sothatanyofthedifferentModelinterfacescanbeconstructedaroundaninferenceGraph.Inparticular,theOntologyAPIprovidesconvenientwaystolinkappropriatereasonersintotheOntModelsthatitconstructs.AspartofthegeneralRDFAPIwealsoprovideanInfModel,thisisanextensiontothenormalModelinterfacethatprovidesadditionalcontrolandaccesstoanunderlyinginferencegraph.ThereasonerAPIsupportsthenotionofspecializingareasonerbybindingittoasetofschemaorontologydatausingthebindSchemacall.Thespecializedreasone。

6、rcanthenbeattachedtodifferentsetsofinstancedatausingbindcalls.Insituationswherethesameschemainformationistobeusedmultipletimeswithdifferentsetsofinstancedatathenthistechniqueallowsforsomereuseofinferencesacrossthedifferentusesoftheschema.InRDFthereisnostrongseparationbetweenschema(akaOntologyAKAtbox)dataandinstance(AKAabox)dataandsoanydata,whetherclassorinstancerelated,canbeincludedineitherthebindorbindSchemacalls-thenamesaresuggestiveratherthanrestrictive.TokeepthedesignasopenendedaspossibleJen。

7、a2alsoincludesaReasonerRegistry.Thisisastaticclassthoughwhichthesetofreasonerscurrentlyavailablecanbeexamined.Itispossibletoregisternewreasonertypesandtodynamicallysearchforreasonersofagiventype.TheReasonerRegistryalsoprovidesconvenientaccesstoprebuiltinstancesofthemainsuppliedreasoners.AvailablereasonersIncludedintheJenadistributionareanumberofpredefinedreasoners:TransitivereasonerProvidessupportforstoringandtraversingclassandpropertylattices.Thisimplementsjustthetransitiveandreflexivepropertie。

8、sofrdfs:subPropertyOfandrdfs:subClassOf.RDFSrulereasonerImplementsaconfigurablesubsetoftheRDFSentailments.OWL,OWLMini,OWLMicroReasonersAsetofusefulbutincompleteimplementationoftheOWL/LitesubsetoftheOWL/Fulllanguage.DAMLmicroreasonerUsedinternallytoenablethelegacyDAMLAPItoprovideminimal(RDFSscale)inferencing.GenericrulereasonerArulebasedreasonerthatsupportsuserdefinedrules.Forwardchaining,tabledbackwardchainingandhybridexecutionstrategiesaresupported.[index]TheInferenceAPI1.GenericreasonerAPI2.Sm。

9、allexamples3.Operationsoninferencemodels-Validation-Extendedliststatements-Directandindirectrelations-Derivations-Accessingrawdataanddeductions-Processingcontrol-TracingGenericreasonerAPIFindingareasonerForeachtypeofreasonerthereisafactoryclass(whichconformstotheinterfaceReasonerFactory)aninstanceofwhichcanbeusedtocreateinstancesoftheassociatedReasoner.ThefactoryinstancescanbelocatedbygoingdirectlytoaknownfactoryclassandusingthestatictheInstance()methodorbyretrievalfromaglobalReasonerRegistrywhi。

10、chstoresfactoryinstancesindexedbyURIassignedtothereasoner.Inaddition,thereareconveniencemethodsontheReasonerRegistryforlocatingaprebuiltinstanceofeachofthemainreasoners(getTransitiveReasoner,getRDFSReasoner,getRDFSSimpleReasoner,getOWLReasoner,getOWLMiniReasoner,getOWLMicroReasoner).Notethatthefactoryobjectsforconstructingreasonersarejusttheretosimplifythedesignandextensionoftheregistryservice.Onceyouhaveareasonerinstance,thesameinstancecanreusedmultipletimesbybindingittodifferentdatasets,without。