简介:Acompressionalgorithmisproposedinthispaperforreducingthesizeofsensordata.Byusingadictionary-basedlosslesscompressionalgorithm,sensordatacanbecompressedefficientlyandinterpretedwithoutdecompressing.Thecorrelationbetweenredundancyofsensordataandcompressionratioisexplored.Further,aparallelcompressionalgorithmbasedonMapReduce[1]isproposed.Meanwhile,datapartitionerwhichplaysanimportantroleinperformanceofMapReduceapplicationisdiscussedalongwithperformanceevaluationcriteriaproposedinthispaper.Experimentsdemonstratethatrandomsamplerissuitableforhighlyredundantsensordataandtheproposedcompressionalgorithmscancompressthosehighlyredundantsensordataefficiently.
简介:Amethodofdetectingdry,icyandwetroadsurfaceconditionsbasedonscanningdetectionofsinglewavelengthbackwardpowerisproposedinthisletter.Thedetectorisusedtoreceivethebackwardscatteredpowerwhichchangeswiththeincidenceangle.Therelationshipbetweenbackwardpowerandincidenceangleisusedtofindouttheeffectiveanglerangeanddistinguishmethod.Experimentandsimulationshowthatitisfeasibletoclassifythesethreeconditionswithinincidenceangleof5.3degree.
简介:Wirelesssensornetworks(WSNs)arebasedonmonitoringormanagingthesensingareabyusingthelocationinformationwithsensornodes.Mostsensornodesrequirehardwaresupportorreceivepacketswithlocationinformationtoestimatetheirlocations,whichneedslotsoftimeorcosts.Inthispaperweproposedalocalizationmechanismusingamobilereferencenode(MRN)andtrilaterationinWSNstoreducetheenergyconsumptionandlocationerror.Thesimulationresultsdemonstratethattheproposedmechanismcanobtainmoreunknownnodeslocationsbythemobilereferencenodemovingschemeandwilldecreasestheenergyconsumptionandaveragelocationerror.
简介:Anopticalfibersensorforultrathinlayersensingbasedonshort-rangesurfaceplasmonpolariton(SRSPP)isproposed,andthesensingcharacteristicsaretheoreticallyanalyzed.Simulationresultsindicatethatevenforadetectinglayermuchthinnerthanthevacuumwavelength,aresolutionashighas3.7×10-6RIUcanbeobtained.Moreover,anaveragethickness-detectionsensitivityof6.2dB/nmisobtained,whichenablesthesensortodetectthethicknessvariationoftheultrathinlayeruptotensofnanometers.Thesensitiveregionofthicknesscouldbeadjustedbytuningthestructureparameters.
简介:basedonoptimaldesignonthecoreelementofthesensor,awirelessandpassivesurfaceacousticwave(SAW)temperaturesensorintegratedwithIDTagwaspresented.Areflectivedelayline,whichconsistsofatransducerandeightreflectorsonYZLiNbO3substrate.Wasfabricatedasthesensorelement,inwhich,threereflectorswereusedfortemperaturesensing,andtheotherfivewerefortheIDTagusingphaseencoding.Singlephaseunidirectionaltransducers(SPUDTs)andshortedgratingwereusedtostructurethesAWdevice,leadingtoexcellentsignaltonoiseratio(SNR).TheperformanceoftheSAWdevicewassimulatedbythecouplingofmodes(COM)priortofabrication.Usingthenetworkanalyzer,theresponseintimedomainofthefabricated434MHzSAWsensorwascharacterized,themeasuredS11agreeswellwiththesimulatedone,sharpreflectionpeaks,highsignal/noise,andlowspuriousnoisebetweenthereflectionpeakswereobserved.UsingtheradarsystembasedonFSCWasthereaderunit.thedevelopedSAWtemperaturesensorswereevaluatedwirelessly.Excellent1inearityandgoodresolutionof士1℃wereobserved.
简介:Underwatersensornetwork(UWSN)adoptsacousticcommunicationwithmoreenergy-consumptionandlongerpropagation-delay,whichbringgreatchallengestoprotocoldesign.Inthispaper,weproposedlevel-basedadaptivegeo-routing(LB-AGR)protocol.LB-AGRdividestrafficsintofourcategories,androutesdifferenttypesoftrafficinaccordancewithdifferentdecisions.Packetsupstreamtothesinkareforwardedunicasttothebestnext-hopinsteadofbroadcastingtoallneighbornodesasinpresentUWSNroutingprotocols.LB-AGRdefinesanintegratedforwardingfactorforeachcandidatenodebasedonavailableenergy,density,location,andlevel-differencebetweenneighbornodes,whichisusedtodeterminethebestnext-hopamongmultiplequalifiedcandidates.Throughsimulationexperiments,weshowthepromisingperformanceofLB-AGR.