简介：Theconventionaldirectpositiondetermination(DPD)algorithmprocessesallreceivedsignalsonasinglesensor.Whensensorshavelimitedcomputationalcapabilitiesorenergystorage,itisdesirabletodistributethecomputationamongothersensors.AdistributedadaptiveDPD(DADPD)algorithmbasedondiffusionframeworkisproposedforemitterlocalization.UnlikethecorrespondingcentralizedadaptiveDPD(CADPD)algorithm,allbutonesensorintheproposedalgorithmparticipateinprocessingthereceivedsignalsandestimatingthecommonemitterposition,respectively.ThecomputationalloadandenergyconsumptiononasinglesensorintheCADPDalgorithmisdistributedamongothercomputingsensorsinabalancedmanner.Exactlythesameiterativelocalizationalgorithmiscarriedoutineachcomputingsensor,respectively,andthealgorithmineachcomputingsensorexhibitsquitesimilarconvergencebehavior.ThedifferenceofthelocalizationandtrackingperformancebetweentheproposeddistributedalgorithmandthecorrespondingCADPDalgorithmisnegligiblethroughsimulationevaluations.
简介：Inordertoachievetheinformationfusioninthetimedomainbasedontheevidencetheory,anevidencecombinationmethodinthetimedomainbasedonreliabilityandimportanceisproposedaccordingtotheideaofevidencediscount.Firstly,thedistortionofthetime-domainevidenceisjudgedbasedonsingleexponentialsmoothing.Thereal-timereliabilityoftheevidenceattheadjacenttimeisobtainedbythereal-timereliabilityassessmentmethodoftheevidencebasedonthecredibilitydecaymodel.Then,therelativeimportanceoftheevidenceattheadjacenttimeisobtainedbycomprehensivelyconsideringimprovedconflictdegreeanduncertainty.Finally,basedonthecriterionofevidencediscountandtheDempster’sruleofcombination,theevidencecombinationiscarriedouttoachievethesequentialcombinationoftime-domainevidence.Thenumericalsimulationandanalysisshowthatthismethodhasfullyembodiedthedynamiccharacteristicsoftime-domainevidencecombination,andithasstrongprocessingabilityforconflictinformationandanti-disturbingability.Theproposedmethodhasgoodapplicabilitytoinformationfusioninthetimedomain.
简介：Focusingontheproblemofgoaleventdetectioninsoccervideos,anovelmethodbasedonHiddenMarkovModel(HMM)andthesemanticruleisproposed.Firstly,aHMMforagoaleventisconstructed.ThenaNormalizedSemanticWeightedSum(NSWS)ruleisestablishedbydefininganewfeatureofshots,semanticobservationweight.ThetestvideoisdetectedbasedontheHMMandtheNSWSrule,respectively.Finally,afusionschemebasedonlogicdistanceisproposedandthedetectionresultsoftheHMMandtheNSWSrulearefusedbyoptimalweightsinthedecisionlevel,obtainingthefinalresult.Experimentalresultsindicatethattheproposedmethodachieves96.43%precisionand100%recall,whichshowstheeffectivenessofthisletter.
简介：Previously,anovelclassifiercalledKernel-basedNonlinearDiscriminator(KND)wasproposedtodiscriminateapatternclassfromotherclassesbyminimizingmeaneffectofthelatter.Toconsidertheeffectofthetargetclass,thispaperintroducesanobliqueprojectionalgorithmtodeterminethecoefficientsofaKNDsothatitisextendedtoanewversioncalledextendedKND(eKND).IneKNDconstruction,thedesiredoutputvectorofthetargetclassisobliquelyprojectedontotherelevantsubspacealongthesubspacerelatedtootherclasses.Inaddition,asimpletechniqueisproposedtocalculatetheassociatedobliqueprojectionoperator.ExperimentalresultsonhandwrittendigitrecognitionshowthatthealgorithmperformesbetterthanaKNDclassifierandsomeothercommonlyusedclassifiers.
简介：Thispaperaddressesthehighdimensionsampleproblemindiscriminateanalysisundernonparametricandsupervisedassumptions.SincethereisakindofequivalencebetweentheprobabilisticdependencemeasureandtheBayesclassificationerrorprobability,weproposetouseaniterativealgorithmtooptimizethedimensionreductionforclassificationwithaprobabilisticapproachtoachievetheBayesclassifier.TheestimatedprobabilitiesofdifferenterrorsencounteredalongthedifferentphasesofthesystemarerealizedbytheKernelestimatewhichisadjustedinameansofthesmoothingparameter.Experimentresultssuggestthattheproposedapproachperformswell.
简介：ThevariousuncertaintiesofMarsenvironmenthavegreatimpactontheprocessofvehiclesenteringtheatmosphere.Toimprovetherobustnessofcontrolsystemagainstthemodelerrorsandtoreducethecomputationalburden,anoptimalfeedbackbasedtrackingcontrollawisdeveloped.Thecontrolschemepresentedinthispaperdeterminestheamplitudeandthereversalsofbankanglerespectivelyinthelongitudinalandlateralflightplane.Ateachcontrolcycle,theamplitudeofthebankangleisobtainedbyanoptimalfeedbackcontrollertominimizetrackingerrors.Thecontrolgainsaretunedaccordingtotheclosed-looperrordynamicsbyusingoptimizationmethods.Thebankreversalsareexecutedifthecrossrangeexceedsapredeterminedcorridorwhichisdesignedbysettingaboundaryfunction.Theaccuracyandrobustnessoftheproposedclosed-loopoptimalfeedbackbasedcontrollawintrackingthereferencetrajectoryisverifiedvia500deviationsimulations,inwhichmodelingerrorsandexternaldisturbancesareconsidered.
简介：Thereadoutintegratedcircuit(ROIC)technologyisoneofthecriticaltechnologiesintheresearchofaninfraredfocalplanearray(IRFPA).Basedonthevirtualinstrumenttechnology,asystemforparametertestofROICisdevelopedforIRFPA.Thecomplexprogrammablelogicdevice(CPLD)isappliedintothesystemtoincreaseitsflexibility.Withhighreliabilityandprecision,alongwiththeintegratedsoftwareandhardwareenvironment,thesystemcantestallkindsofROICs.
简介：Aswitchingvariabilityindex(SVI)constantfalsealarmrate(CFAR)detectorisproposedforimprovingthedetectionperformanceofVI-CFARdetectorsinmultipletargetsbackgrounds.Whenthepresenceofnon-homogeneityinCFARreferencewindowsisindicatedbyaVI-CFARdetector,aswitchingCFARdetectorisintroducedtooptimizetheperformanceoftheVI-CFARdetectorinhomogeneous,multipletargetsandclutteredgebackgrounds.ThestructureandparametersselectionmethodoftheSVI-CFARdetectorispresented.ComparisonswithclassicCFARdetectorsandrecentlyproposeddetectorsarealsogiven.TheoreticalanalysisandsimulationresultsshowthatSVICFARdetectormaintainsthegoodperformanceoftheVI-CFARdetectorinhomogeneousandclutteredgebackgrounds,whilegreatlyimprovingthecapacityofanti-multitargets.
简介：Losslessdatahidingcanrestoretheoriginalstatusofcovermediaafterembeddedsecretdataareextracted.In2010,Wangetal.proposedalosslessdatahidingschemewhichhidessecretdatainvectorquantization(VQ)indices,buttheencodingstrategiesadoptedbytheirschemeexpandthefinalcodestream.ThispaperdesignsfourembeddingandencodingstrategiestoimproveWangetal.'sscheme.TheexperimentresultoftheproposedschemecomparedwiththatoftheWangetal.'sschemereducesthebitratesofthefinalcodestreamby4.6%andraisesthepayloadby1.09%onaverage.
简介：Theattitudecontrolsystemdesignanditscontroleffectareaffectedconsiderablybythemass-propertyparametersofthespacecraft.Inthemissionofon-orbitservicing,asfuelisexpended,orthepayloadsareaddedorremoved,thecenterofmasswillbechangedincertainaxe;consequently,somethrusters’directionsaredeviatedfromthecenterofmass(CM)incertainplane.TheCMofassembledspacecraftestimationandthrusterdirectioncontrolarestudied.Firstly,theattitudedynamicsoftheassembledspacecraftisestablishedbasedontheNewton-Eulermethod.Secondly,theestimationcanbeidentifiedbytheleastrecursivesquaresalgorithm.Then,aschemetocontrolthethrusters’directionsisproposed.Byusingthegimbalinstalledattheendoftheboom,theangleofthethrusteriscontrolledbydrivingthegimbal;therefore,thrusterscanbedirectedtotheCMagain.Finally,numericalsimulationsareusedtoverifythisscheme.Resultsofthenumericalsimulationsclearlyshowthatthiscontrolschemeisrationalandfeasible.
简介：Inthispaper,theforwardingobjectiveandmobilitylawofnodesinopportunisticnetworksarefirstinvestigatedtoestablishamathematicalmodelforfurtheranalysis,thenagraduallyaccelerateddataforwardingalgorithmisproposed.Inthisalgorithm,accordingtothedistancebetweendatacarriers(nodes)andthedestination,someintermediatenodesareselectedtorelaythedata.Especially,theforwardedcopiescanbeincreasedwhenthedelayreachesathreshold,toguaranteetherequireddeliveryratio.Thesimulationresultsshowthattheproposedalgorithmcaneffectivelyreducethestorageoccupanciesofnodesandforwardingdelay,andguaranteethedeliveryratiosimultaneously.
简介：Anovelmethodfordesigningabeam-switchingantennawiththeplanedipoleispresented.Theantennaiscomposedofdoubledipolesplacedatthecenterofanactivesquarestructurethatisdividedinfourequalsectorsbymetallicsheets.Metallicpatchesattheoutsideofthestructureareusedtoenhancetheradiationperformanceoftheantenna.Ineachstep,thediodesinonesectorareon,whereasotherdiodesareoff.Thesectorwithoff-statediodesdefinesthedirectionoftheradiationpattern.AnantennamodelisdesignedonthesubstrateofFR4.Theproposedantennaoperatesfrom4.8GHzto5.5GHzwithgainof6.3dBiandF/B(fronttobackratio)of13.2dBiwhentheoperatingfrequencyis5.2GHz.Theantennaradiationpatterncanbesweptintheentireazimuthplaneinfourstepswitha3dBbeamwidthof90.Theresultsrevealthattheantennacouldbeusedinthebasestationofthewirelesscommunicationsystems.
简介：Theimpactofmutualcouplingontheperformanceofmultiple-inputmultiple-output(MIMO)systemswithcompactantennaarraysisanalyzed.ThisarticleaimstousetheS-parametermodelingapproachtoexaminetheimpactofmutualcouplingonthreesystem-relatedperformancemeasures:antennacorrelation,efficiencyandbandwidth.Itisshownthatimplementingagoodmatchingnetworkcandrasticallyimprovethesystemperformanceinthepresenceofstrongmutualcoupling.Experimentresultsindicatethesuperiorityofcross-shapedantennatodipoleantenna.
简介：Thispaperpresentsanewmethodbasedonasecond-orderstochasticmodelforcomputerintrusiondetection.Theresultsshowthattheperformanceofthesecond-orderstochasticmodelisbetterthanthatofafirst-orderstochasticmodel.Inthisstudy,differentwindowsizesarealsousedtotesttheperformanceofthemodel.Thedetectionresultsshowthatthesecond-orderstochasticmodelisnotsosensitivetothewindowsize,comparingwiththefirst-orderstochasticmodelandotherpreviousresearches.Thedetectionresultofwindowsizes6and10isthesame.
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