撰写上下文感知的真实世界服务(IJWMT-V1-N3-7)

I.J.WirelessandMicrowaveTechnologies,2011,3,40-45PublishedOnlineJune2011inMECS()DOI:10.5815/ijwmt.2011.03.07Availableonlineat*1,JiazhengTiana,*2aSchoolofComputer&CommunicationEngineering,ChinaUniversityofPetroleum,DongYing,ChinabSecondaffiliation,Address,CityandPostcode,CountryAbstractAdvancesintheareasofsmartembeddeddevices,computingandnetworkingareleadingtotheemergenceoftheInternetofThings(IoT)composedofmillionsofheterogeneousdevices.Thesedeviceswillbeinterconnected,providingandconsuminginformationavailableonthenetworkandcooperate.Astheimprovementoftheperformanceofindustrialprocesses,theservice-orientedapproachcanbeadoptedforsmartembeddeddevices.Eachdevicecanofferitsfunctionalityasservices.Insuchinfrastructures,traditionalwebservicecompositionscannotadapttothedynamicenvironmentfortheInternetofThings.Inthispaper,weproposeanapproachtocomposeserviceswithcontext.ItcannotonlyadapttodynamicenvironmentfortheInternetofThings,butalsosatisfytheuser’spreferences.Wefirstbuildcontextontologytodescribethescenarioforuser.Accordingtocontextinformation,theservicecompositionprocessispresented.IndexTerms:InternetofThings;Real-WorldService;ServiceComposition;ContextOntology©2012PublishedbyMECSPublisher.Selectionand/orpeerreviewunderresponsibilityoftheResearchAssociationofModernEducationandComputerScience1.IntroductionInrecentyears,smartembeddeddeviceshavedevelopedrapidly.Theyarebecomingcheaper,smallerandmorepowerful.AccordingtotheInternetofThingsvision[1],themostdeviceswillhavecommunicationandcomputationcapabilities,whichtheycaninteractandcooperatewiththeirsurroundingenvironment.AlongwiththedevelopmentofSOA(Service-OrientedArchitecture),servicetechnicalgraduallybecomemainstreamtechnologiesforinformationintegrationofintheInternetenvironment.Asthesedevicesneedtointeroperate,theintegrationofdevicesintothebusinessIT-landscapethroughSOA[2][3]isapromisingapproachtoconnectphysicalobjectsandtomakethemavailabletoIT-systems.Eachdeviceshouldofferitsfunctionalityasstandardservices,whileinparallelitcandiscoverandinvokeotherserviceson-demandfromotherdevices.InthefutureInternet,real-worlddeviceswillbeabletooffertheirfunctionalitybySOAP-basedwebserviceorRESTfulAPIs[4],enablingothercomponentstointeractwiththemdynamically.Asthereal-worlddevicesarerelateddirectlytothephysicalworld,theservicethattheyprovidedisoftenreferredasreal-worldservice.*Correspondingauthor:E-mailaddress:*[e-mail];*[e-mail]-worldServiceWithContext41Comparedwiththetraditionalenterpriseservices,therearesomedifferences.Firstly,real-worldservicesprovidereal-timedataaboutthephysicalworld,notvirtualentities.Secondly,real-worldservicesaredeployedonresourceconstraineddevices,withlimitedcomputing,communicationandstoragecapabilities.Additionally,real-worldservicesarefoundinhighlydynamicenvironmentswheredevicesandtheirunderlyingservicesconstantlydegrade,vanish,andpossiblyreappear.Thisimpliestheneedforautomated,immediatediscoveryofdevicesandservicesaswellastheirdynamicmanagement,andareasonableservicecompositionmethodbasedonspecificapplicationenvironmenttomeetuser’srequest.Ourworkaimsattakingcontextinformationtoguidecompositionsothatwecangetthebestsatisfyingcomposedservice.InSection2,wediscussrelatedwork.InSection3,webuildcontextontology.InSection4,weproposeacontext-basedwebservicecompositionapproach.Finally,Section5givesconclusionofourwork.2.RelatedWorkCurrently,servicecompositionhasbecomeahottopicintheindustryandacademicfield.Researchershaveproposedseveralservicecompositionapproaches.Accordingtothetechnicaltheyrelyon,wecandividethemintotwocategories.Onecategorydefinesthebusinessprocesstosupportservicecomposition,itscompositionpathispredefined,soitisdifficulttomeetuser’sneeds.Theotherbasedonsemanticsordomainrelatedtosatisfyuser’spersonalizeddemand.Butthesetwocategoriesdidnotconsidertheenvironmentinformationinwhichservices,makingservicecompositionlackofadaptability.Therefore,theresearchersintroducedcontextconcept,andproposedservicecompositionbasedoncontextinformation[5][9],butdidnotgivespecificcompositionmethod.Asforthereal-wordservicesthataredirectlylinkedtothephysicalworld,servicecompositionshouldadapttothedynamicchangesofdevicesorresources,andserviceselectionshoulddependonenvironmentinformationinwhichservicesandresourcesthatservicesneed.Inaddition,weshouldconsiderusersdemandonnon-functionalpropertiesofservices.Ourworkisdifferentfromtraditionalcompositions,wetakeintoaccountcontextinformationtofilterinappropriateservicesandfindthebestsolutionforthegivenscenario.3.ContextOntologyContextisinformationthatqualifiesthephysicalworld,andcanhelpinbothreducingthenumberofservicesreturnedtotheuser,aswellasinfindingthemostappropriateservicesforthecurrentenvironment.ThedefinitionofcontextprovidedbyDey&Abowdiswidelyaccepted,“Contextisanyinformationthatcanbeusedtocharacterizethesituationofanentity[6].”Anentityisaperson,place,computationalentity,orobjectwhichisconside