简介:Nearfieldcommunications(NFC)isanewlythrivedtechnologyinrecentyears.Thistechnologyhasbeeninstalledonmanykindsofmobilephonesystems,especiallytheAndroid.However,thereisnounifiedandcompleteframeworktoaccessNFCsofar.ThecurrentsoftwarestackofNFCmerelyimplementsdataobtainingfeatures,ignoringthepost-processingofdataandlackingacertainsecuritymechanismforNFC,whichresultsininefficiencyandinconvenienceforsoftwaredevelopmentandmaintenance.Aboveall,securityproblemscouldbecausedduetotheabsenceofthesecuritymechanism.Toproposeasolution,thispaperpresentsabrand-newframeworkforNFCutilizationbyanalyzingandconstructingaservicemodel.Thus,theproposedframeworkencapsulatesthecurrentNFCstackonAndroid,formulatingathree-layerstructureafterimplementingtheencapsulationandparsingofNFCrecords,whichultimatelyenablesanXMLdocumenttodescribetheconfigurationofNFCanditsrelatedserviceflow.Simultaneously,acontext-awarenessmodelisproposedandbuiltinthispapertoequiptheframeworkwiththecapabilityofadaptingtodifferentphysicalenvironment.
简介:Agoodmodelcanextractusefulinformationaboutthetarget'sstatefromobservationseffectively.Therearemanymodelsusedtotrackinga,maneuveringtargetsuchasconstant-velocity(CV)model,Singeraccelerationmodel(zero-meanfirst-orderMarkovmodel)andcurrentmodel(mean-adaptiveaccelerationmodel),etc.Whileduetothecomplexityofmaneuveringtarget,toseekthetargetmodelwhichcangetbetterperformanceisstillasubjectworthyofstudy.BasedonstatisticsrelationbetweentheautocorrelationfunctionandthecovarianceofMarkovrandomprocessing,thispaperdevelopsamodelwhichcanadaptivelyadjustsystemparametersonline.Simulationsshowthegoodestimationperformancegetbythemodeldevelopedhere,andcomparingCV,Singerandcurrentmodels,themodelcanadaptivelygetthemodelparameterwhiletrackingthetrajectoryandneedn'tdoingseveralteststoobtainaprioriparameter.
简介:Fieldcomputation,anemergingcomputationtechnique,hasinspiredpassionofintelligencescienceresearch.Anovelfieldcomputationmodelbasedonthemagneticfieldtheoryisconstructed.Theproposedmagneticfieldcomputation(MFC)modelconsistsofafieldsimulator,anon-derivativeoptimizationalgorithmandanauxiliarydataprocessingunit.ThemathematicalmodelisdeducedandprovedthattheMFCmodelisequivalenttoaquadraticdiscriminantfunction.Furthermore,thefiniteelementprototypeisderived,andthesimulatorisdeveloped,combiningwithparticleswarmoptimizerforthefieldconfiguration.Twobenchmarkclassificationexperimentsarestudiedinthenumericalexperiment,andonenotableadvantageisdemonstratedthatlesstrainingsamplesarerequiredandabettergeneralizationcanbeachieved.
简介:Asatypicalcleanandrenewableenergy,windpowerisbecomingmoreandmorewidelyusedinelectricalindustry.However,itscharacteristicsofrandomandintermittenthavebroughtseriousproblemstothepowersystem,suchasvoltagefluctuationandinsufficientreactivepower.BasedontheK-meansclusteringalgorithm,thispaperclassifiesthedoubly-fedinductiongenerators(DFIG)accordingtotheoperationofpropellerpitchanglecontrol.Atthesametime,toobtaintheoptimalparameter,advancedparticleswarmoptimization(PSO)isused.ThenthedynamicmodelofDFIGunderthenetworkfaultconditionisbuilt.Whatismore,therolethatcrowbarcircuitplaysinlowvoltageridethrough(LVRT)isdiscussed.Finally,simulationsinDigSILENTverifythemodel.
简介:Thisarticlepresentsadatamanagementsolutionbasedonthedatadistributionservice(DDS)communicationmodel.ThebasicDDScommunicationmodelconsistsofaunidirectionaldataexchangewhereapplicationsthatpublishdata'push'therelevantdata,whichisupdatedtothelocalcachesofco-locatedsubscriberstothedata[1].DDShasnospecifiedcenternodetoforwarddatapacketsandmaintainthecommunicationdata.Thistypeofpublish-subscribe(P/S)modelpresentsintegrityandconsistencychallengesindatamanagement.Unlikepeer-to-peer(P2P)distributedstorage,DDSapplicationshaveahardreal-timeenvironmentandfewerdatafeatures,andthecoreproblemisensuringtheintegrityandconsistencyofdataindistributedsystemsunderthishardreal-timeenvironment.ThisarticlebeginswithabriefintroductionofthecommunicationmodelusedbyDDS,thenanalyzespersistentdatamanagementproblemscausedbysuchmodel,andprovidesanappropriatesolutiontotheseproblems.Thissolutionhasbeenimplementedinaprototypesystemofthereal-timeservicebus(RTSB)ofTsinghuaUniversity.
简介:Usingultrashort-pulseradarwithcompactvivaldiantennas,thesimulationexperimentofbreastcancerdetectionhasbeenperformedinasyntheticbreastphantom.Twometallicballswith9mmand6mmindiameterareusedastumorsinourexperiment.Theimagereconstructionsofthebreastmodelswithtumorsusingreflectiondatahavebeenpresentedbyaconfocalmicrowaveimagingtechnique.Themethodcanbeusedforapulsecompressiontechniquetoreflectedwavesforclearimageformation.