外文翻译原文-启用web的设施管理的无线传感器网络

500IEEESYSTEMSJOURNAL,VOL.2,NO.4,DECEMBER2008WebEnabledWirelessSensorNetworksforFacilitiesManagementApostolosMalatras,Abolghasem(Hamid)Asgari,Member,IEEE,andTimothyBaugAbstractThecornerstoneofbuildingandoverallfacilitiesmanagementisaccurateandup-to-datemonitoringofthecontextoftheenterprisebuildingenvironmentanditssurroundings,usuallyperformedbysensorsdispersedthroughoutthepremises.Currently,themajorityofbuildingmanagementsystemsistightlycoupledwiththesensorsthattheyutilize,restrictingtheirexten-sibility.TheemergenceofWirelessSensorNetworks(WSNs)hasbroughtsignificantbenefitsasfarasmonitoringisconcerned,sincetheyaremorecost-efficient,duetothelackofwiringinstal-lations,comparedtowiredsensorsolutionsandallowforflexiblepositioningofthesensors,especiallywhenbuildingretrofittingisconcerned.Inlinewiththeestablishedmovetowardsintegrationofenterpriselevelservices,itisbeneficialtoconsidertheWSNswithinthatscope.Inthispaper,weproposetoexploitaserviceorientedarchitecturefordevelopinganenterprisenetworkingenvironmentthatisusedforintegratingfacilitiesmanagementapplicationsandbuildingmanagementsystemswithotheropera-tionalenterprisefunctionsforthepurposeofinformationsharingandmonitoring,controlling,andmanagingtheenterpriseenvi-ronment.TheWSNisviewedasaninformationserviceprovidernotonlytobuildingmanagementsystemsbutalsotowiderappli-cationsintheenterpriseinfrastructure.Weprovidespecificationandimplementationdetailsoftheproposedarchitectureanddiscussevaluationplanning.IndexTermsBuildingManagementSystem(BMS),facilitiesmanagement,serviceorientedarchitecture(SOA),Webservices,wirelesssensornetwork(WSN).I.INTRODUCTIONBUILDINGManagementSystems(BMSs)manageandnormallycontrolandadjustthefunctionalityofbuildingsystemsandservicesfromtheperspectiveoftheiroccupants,withexemplarcasesbeingthatofheating,ventilationandairconditioning(HVAC),security,electricitysystems,lighting,accesscontrol,resourcemonitoring,etc.Intheirconventionalmodeofoperation,thesesystemsaremanagedindependently,leadingthustohighoperationalcosts,cumbersomeoverallmanagement,andincreasedlevelofexpertiserequired.Lately,therehasbeenaparadigmshifttowardsnovelarchitecturesthatallowforintegratedBMSsandsupportbuildingautomationandcontrolunderaunifyingframework.ThisenablesthebuildingmanagertohaveasinglepointofinteractiontocontrolalltheseManuscriptreceivedJanuary21,2008;revisedJuly21,2008.FirstpublishedNovember18,2008;currentversionpublishedDecember31,2008.ThisworkwassupportedinpartbytheCommissionoftheEuropeanUnionNMPI3CONFP6Project,NMP026771-2.TheauthorsarewiththeThalesResearchandTechnology,Berkshire,RG20SB,U.K.(e-mail:;;).Colorversionsofoneormoreofthefiguresinthispaperareavailableonlineat.DigitalObjectIdentifier10.1109/JSYST.2008.2007815facilitiesinanintegratedmanner.Inthisrespect,thenotionoffacilitiesmanagementcanbedefinedasanintegratedprocesstosupportandimprovetheeffectivenessoftheprimaryactivitiesofanorganizationbythemanagementanddeliveryofagreeddistributedsupportservicesfortheappropriateenvironmentthatisneededtoachieveitssetobjectives1.Oneofthemostimportantparametersregardingfacilitiesmanagementisaccuratemonitoringofthebuildingsystemanditssurroundings,usuallyperformedbysensorsdispersedthroughoutthepremises.Existingbuildingsystemsaretightlycoupledwiththesensorstheyutilize,restrictingthegenericextensibilityoftheoverallarchitecture.TheemergenceofWirelessSensorNetworks(WSNs)hasbroughtsignificantbenefitsasfarasmonitoringisconcerned,sincetheyaremorecost-efficient(becauseofthelackofwiredinstallations)com-paredtotheirwiredcounterparts,whileadditionallytheyallowforflexiblepositioningofthesensordevices.Inlinewiththeestablishedmovetowardsintegratedenterprisearchitectures,itisbeneficialtoconsidertheWSNswithinthatscope.TheWSNarchitectureshouldsubsequentlybedesignedinsuchamanner,soastoallowitsstraightforwardintegrationtothebuildingenterpriseinfrastructure.Thenecessitythereforeemergestoadoptabroaderperspec-tiveregardingtheoverallarchitectureofBMSsthatwillbeopenandextensible,allowingfordynamicintegrationofnovelorup-dated/advancedbuildingservices.Furthermore,thediversityoftheofferedbuildingservicesneedstobeaddressed,asdotheev-identscalabilityissuessubjecttotheparticularbuildingenviron-mentapplicationdomain.Theoverallbuildingservicesarchi-tectureshouldalsorealizealong-standinglifecycleviewtakingintoaccounttheneedsofallstakeholders,whichinturnfurthermotivatestheneedfordesignflexibility.Themostprominentapproachtowardsanenterprise-wide,openframework,whichsatisfiestheaforementionedrequire-ments,isthatofserviceorientedarchitectures(SOAs).InthecaseofSOAs,allarchitecturalelementsaredecoupledandcon-sideredasserviceprovidersandconsumers.Servicediscoveryandaccesstotheservicesisperformedinadynamicmanner,ensuringthusagenericandextensibledesign.WSNscanbere-gardedasserviceprovidersrelatedtobuildinginformationmon-itoringandshouldthereforebeconsideredwithinthescopeofthefacilitiesmanagementSOA,whichpromotestheconceptofdynamic,coordinated,anddistributedbuildingservicesman-agement.Webservicesconstitutethemostsignificanttechno-logicalenablerofSOAsduetotheinteroperabilitythattheyofferandthefactthattheycaneasilysupporttheintegrationofexistingsystems.Thispaper,presentsageneralframeworktointegrateWSNsinanoverallSOAregardingfacilitiesmanagement.Athorough1932-8184/$25.002008IEEEMALATRASetal.:WEBENABLEDWIRELESSSENSORNETWORKSFORFACILITIESMANAGEMENT501requirementsanalysisfortheparticularapplicationdomainisperformedandthecorrespondingfunctionalityisexplainedandmappedonspecificelementsofthedesignarchitecturethatwepresent,whileweadditionallyproviderelevantspecificationandimplementationdetails.Theremainderofthispaperisstructuredasfollows.AfterthisbriefintroductioninSectionI,SectionIIdescribestheWSNno-tionandrelatedtechnologies.SectionIIIreviewsrelatedworkintheareaofservice-orientedframeworksforthewebenable-mentofsensornetworksaswellasbuildingservicesandfacili-tiesmanagementingeneral.SectionIVdiscussestheproposedWSNarchitecture,includinganalysisoftherelevantrequire-mentsthatmotivateourwork.ThespecificationoftheproposedarchitectureisgiveninSectionV,whileSectionVIconcludesthepaperanddiscussesplanningforevaluationandotherissuesforfuturework.II.WIRELESSSENSORNETWORKSTechnologicaladvancesinareassuchascomputingplatformminiaturization,lowpowerradiotransceiversandnetworkself-organizationprotocolshaveenabledthedevelopmentofsmall,non-intrusive,andconfigurablesensorplatforms,whichcanop-erateforsignificantlengthsoftimeonlowenergysupplies,andautomaticallyconfigurethemselvestoformaninformationre-portingnetworkondeployment,knownaswirelesssensornet-works.WSNs2,3areamajordisruptivetechnology,revolution-izingtherelationshipbetweenthedigitalandthephysicalworld.Thekeydisruptionisnotonlyinthesensortechnologyarena,butalsointhewaysensorsaredeployedandused.Therevolu-tionliesintheabilitytorapidlydeploylargenumbersofsensorswithanticipatedminimalcapitalandoperationalexpendituresoverheads,andtobeabletoexploittheminflexibleandvariedwaysovertime.Thisleadstosignificantincreasesinavailabilityandgranularityofphysicalworldsensing,inanever-increasingfieldofapplications,e.g.,environmental,structural,physiolog-icalsensing,etc.Althoughunitcostsarestillhigh,theyareexpectedtodropsignificantlywiththelargescaleadoptionofthetechnology.Giventheproductionvolumesrequiredtomeetforecasteddemandincomingyears,thehardwarecostswillre-ducesofarastomakethesensornodesdisposableitemsinmanyapplications.SizeandenergyconsumptionaretheforemostconstraintsthatWSNplatformshavetoreconcile,anditthissetofcon-straintsthatisdrivingtheirdesignandoperation.Asensornodeormoteismadeupoffivemaincomponenttypes/blocks,namelytheprocessor,thesensors,thecommunicationradio,thepower,andperipherals.Atthecenterofthesensordeviceisaprocessor,whichco-ordinatesallotherfunctions.Theprocessorsonsensornodeshavelatelyincreasedincapability,andcancurrentlyoffersatis-factorydataprocessingfunctions.Giventheenergyconstraintsofthedevices,andthefactthatprocessingrequireslessenergythancommunication,itisattractivetoprocessdatalocallytore-ducetheamountofdataneedingtransmission.Typicalexamplesofnodelevelprocessingincludeaveragesovertime,thresholdbasedalarms,etc.Thesensorblockisthefocalblockofthedevice.Thisblockmaycontainoneormoresensors,whichmaybeidentical(forredundancyand/ormultiplesourcesforqualityofinformationestimation)ordifferent.Thesensorblockisdrivenbytheprocessor,whichdetermineswhenthesensorsshouldtakeareading,accordingtotheoperationalrequirementsprogrammedintothedevice.Thecommunicationradioblockisoneofthedistinctivecom-ponentsofthesensornode.Wirelesscommunicationisfunda-mentaltotheWSNconcept.Thecommunicationradioisre-quiredtobeduplex(i.e.,abletotransmitandreceive),andmustbesupportedbyadequatelinklayerandnetworklayerproto-colstoalloweffectiveandefficientuseofthephysicalmediumandthedeploymenttopology.Althoughmanydeviceshaveap-pearedusingproprietaryradiosandprotocols,themostpromi-nentoptionsincludethefollowingstandards:Bluetooth4,5andZigBee/IEEE802.15.46,7.Powerisobviouslyessential.However,thepowersourcesforthesedevicesareverylimited.Giventhedeploymentcon-straints,thedevicesmaynotbemainspowered.Additionally,givensizeconstraints,thebatteriescannotbelarge,andtokeepoperationalexpenditurecostsdown,batteryreplacementmustberare.ThiscreatesoneofthemainchallengesoftheWSNfield,whichisthescarcityofenergyandshouldbeconsideredwhendevelopinganysolutiontargetedforWSNs.WediscusspowermanagementissuesinSectionIV,wherewealsodescribethedesignofourproposedarchitecture.Theblockregardingperipheralsincludesavarietyofaddi-tionalfunctions,whichmaybedesirableonasensornode,al-thoughnotessential.Examplesincludestoragecapacity(clearlytheprocessorrequiressomestorageforitsoperation,butthisreferstoadditionaldatastorage)andexternalclocksfordevicesynchronizationandeventtimestamping.Therearemanypo-tentialadditionalfunctions,whichcouldbeaddedtotheperiph-eralblock,buttheirbenefitshavetobeweighedagainsttheim-pactinsizeandenergyconsumption.Wirelesslynetworkingsensornodestogetherisoneoftheirkeycapabilities,whichsupportstheincreaseinsensinggranu-larityandthelowdeploymentcosts.Traditionally,sensorplat-formshaveeitherneededtobequeriedlocallyorconnectedtoacentralmonitoringstation,withconstraintsconcerningthedis-tancebetweenthecontrolstationandeachsensor,andlimitsonthenumberofsensorsacontrolstationisdesignedtosup-port.Movingfromthismodeltoasharedmedium,packet-basedcommunicationnetworkisamajorstep,whichincreasesthecomplexityofthecommunicationmodel(requirementfornet-workingprotocols),butdramaticallyincreasestheflexibilityandpotentialcapabilities.AWSNismadeupoftwotypesofdevices:wirelesssensornodesandgateways.Thewirelesssensornodehasalreadybeendescribedandisthecoreofthesensornetwork.Agatewayde-viceishoweveralsonecessaryinordertoconnectthewire-lesssensornetworktosomeexternalsystem,suchasawidernetworkandtosupportthescalabilityofmanagementopera-tions,aswellastheoverallWSNreliabilityandsurvivability(seeFig.1).502IEEESYSTEMSJOURNAL,VOL.2,NO.4,DECEMBER2008Fig.1.WSNexemplarydeploymentarchitecture.III.RELATEDWORKAutomatingthefacilitiesmanagementdomainbyenablingtheemploymentofintelligentoperationsandofunsupervisedmanagementandcontrolhasattractedsignificantresearchin-terestoverthepastyears8.Successfulexamplesofindividualautomatedbuildingservicesandsystemsexist,e.g.,HVACcon-trols,securitysystems,firealarms,etc.Theirintegrationandtheadoptionofabuilding-widedegreeofautomationhavenonethe-lessnotbeenreviewedthoroughly.Thereisanevidentlackofholistic,integratedbuildingmanagementsolutions,sincecur-rentrelevantapproachesarenotaddressingtheproblematasatisfactorylevel9.Theapproachesthathavebeenmostpro-foundlyestablished,i.e.,cross-protocolgatewaysandstandardcommunicationprotocolshavenotsatisfiedthedesiredexpec-tationsandhavehadanarrowapplicabilityfield.Theneedforbuildingservicesandsystemsintegrationissubsequentlyevi-dentduetothenumerousbenefitsitcanbringtoboththeoccu-pantsofthebuildingaswellasthefacilitiesoperators/managers10.Morerecentapproachesareexploitinganddevelopingmid-dlewaretechnologiestosupportbuildingautomationsystemsandbuildingservicesatahigherlayer1113,asaresponsetothefirmnecessityforintegration.Suchnovelapproachesforintegrationdonotintendtosubstituteproprietary,low-levelbuildingautomationsystems.Thefocusisonprovidingsmoothintegrationofdiversesystemsandservicesbyusingthenotionofmiddlewareabstraction,i.e.,theindividualbuildingsystemscontinuetooperateasoriginallyconfiguredbytheirmanu-facturers,yetmiddlewarewrapperapplicationsareusedtofacilitateinteractionandinteroperability.Amongtheavailablemiddlewaretechnologies,theonesthathavebeenutilisedinbuildingautomationenvironmentsincludeopenconnectivity(OPCusingCOM/DCOMasthecommunicationinterfacetechnologies)11,13,CORBA14,andJAVA/RMI15.Mostoftheaforementionedmiddleware-basedsolutionsbearinherentproblems,whicharepredominantlyfocusedonthefactthattheproposedsolutionsarebasedonproprietary,closedtech-nologiessuchasCOM/DCOMthathinderinteroperability.Fur-thermore,theyhavebeendesignedwithaspecificapplicationinmind;hence,theirpotentialforextensibilityislimited.OneshouldalsoconsidertheimportanceofincorporatingBMSsandautomationsystemsintheoverallenterprise-networkingenvi-ronment,anaspectthathasbeenneglectedinmostmiddleware-basedsolutions.Therehasbeenawiderspectrumparadigmshifttowardstheadoptionofenterprise-widearchitectures,whichtakeintoaccountcross-layerinteractionsandbusinessobjec-tivesalongsidesystemrequirements.Itbecomesthereforeevi-dentthatitwouldbebeneficialtoexploitsuchenterprisearchi-tectures,drivenbytheSOAparadigm,inthebuildingmanage-mentrealm16,17.Underthisprism,ITandbuildingman-agementconvergenceislogicallypromoted,whileallowingforopen,flexible,andscalableenterprise-widearchitecturestobebuilt.Furthermore,followingthisstreamwillenablethemuchdesirableaccessibilityofoverallfacilitiesmanagementovertheInternet.Sucharesearchdirectionhasalsobeenimpliedbyre-centworkin11,wherethereareneverthelessproblemsaspre-viouslyindicated.ThemaindriversbehindtheconvergenceofITandex-istingbuildingsystemsaretoreduceoperatingcost,toreducecomplexityofthesystem,hencetraining/experiencerequiredofstaff,toreducecapitalcosts(wiring,equipment,etc.),andtoprovidevalue-addedservices.Thesynergycreatedbycombiningbuildinginfrastructureanddatacommunicationsreducesoperationalcostsandcreatesnewserviceopportunities18.Themainimplicationofthissynergy,whichisenabledbyenterprise-widearchitectures,regardingfacilitiesmanagementautomationisthatitprovidesBMSsandbuildingautomationandcontrolsystemswithaccesstoadditionalinformationthatwillenablethebuildingtobeusedmoreeffectively19.Thisinformationasfarastheautomatedbuildingcontrolsemanticdomainisconcernedcanbecollectedfromavarietyofsources,rangingfromphysicallysenseddata(structural,environmental,physiological,etc.)toelectronicrecords(buildingmaintenancerecordsandschedules,personnelprofilesandcalendars,busi-nessprocessesandpolicies,etc.).WSNsasinformationsourcesarealternativestowiredsensorsolutionsthatadditionallyfacilitatesensordeploymentandre-ducecosts,mostlythroughtheabsenceofwiringmaintenance20.TheapparentbenefitsthatcanbeachievedbyutilizingWSNtechnologyinbuildingautomationhaveledtoanumberofrelatedresearchefforts1828.Initialworkontheareacon-sistedofcost-benefitanalysesfortheuseofWSNsinbuildingoperations,comparedtoemployingtheirwiredcounterparts.Theseanalyseswerecomplementedwithreviewsofrelevanttechnologicaladvancesthathighlightedthepenetrationandad-vantagesofWSNapproachesinthebuildingmanagementdo-main18,21.LimitedresourcesofWSNnodeswerestudiedin20inordertoexaminethefeasibilityofimplementingstan-dardconceptsofbuildingautomationsystems,e.g.,BACnet31,insensorplatforms.Thiswasdeemedaspossible,withlimitationsnonethelessintheirportabilityandease-of-develop-ment.Thefirstefforttowardsunderstandingtheneedforexposingtherichnumberofsensorsandtheircorrespondingreadings,i.e.,datameasurements,inawiderscopeacrosstheInternetwaspresentedin22.TheIrisNetarchitecturedescribedin22wasbasedonagenttechnologyinordertocollectsensordataandor-ganizethemintoadistributeddatabasethatcouldbeaccessedMALATRASetal.:WEBENABLEDWIRELESSSENSORNETWORKSFORFACILITIESMANAGEMENT503inadistributedmannerovertheInternet.Theuseofagentsisconsideredrestrictingandfurthermorethissortofarchitecturedidnotenvisageanenterprise-widescope,soastocooperatewithotherapplications;theworkin22ratherconcentratesonthesensornetworkaspects,yetneverthelessformsamotivatingandnoteworthyeffort.Asimilarapproachisfollowedin28,wherebuildingautomationcasestudiesareexamined.Wirelesstechnologiesareusedformonitoringandtheexposedinforma-tionismadeavailablethroughwebpages,adoptingasbeforeanarrowscoperegardingextensibility.ResearchworkintheareaofWSNshasmovedfromthetradi-tionalviewofsensornetworksasstaticresources,fromwhichdatacanbeobtained,tothemoreinnovativeviewofsystemsengineeringingeneral,whereeverythingisconsideredinaser-vice-orientedperspective2327,33.ThisallowsWSNstoberegardedasserviceproviders,i.e.,informationservices,andconsequentlymoreadvanced,dynamic,reusable,andextensibleapplicationsandoperationstobeprovided.Enterpriseapplica-tionintegrationisthereforeadditionallyfacilitated,particularlywithBMSsforfacilitiesmanagement.ThebenefitsofexposingsensornodesandsensornetworksasserviceprovidersinageneralizedSOAmotivatedtheemer-genceoftheSensorWebEnablement(SWE)activity33bytheOpenGeospatialConsortium(OGC)32.ItisessentiallyasetofstandardsthatallowforexposingsensornetworksasWebservicesmakingthemaccessibleviatheWeb.TheSWEinitia-tiveisfocusedonstandardsthatenablethediscovery,exchangeandprocessingofsensorobservations,aswellasthetaskingofsensornodes.TheapplicationareaofSWEwasplannedtobegenericandhencesomeaspectsofitappeartoocomplexintheirstrivetoincorporateallpossiblefeatures;ithasneverthelesssofarfocusedonfactorssuchasgeolocation,remotepositioning,andscientificapplications.Whilethisworkisavaluablestartingpoint,itistoogenerictobedirectlyapplicable,andrequirestai-l