简介:SiliconPhotodiodewithVerySmalSensitiveArea①YINChangsong,LIXiaojun(WuhanUniversity,Wuhan430072,CHN)Abstract:ThesiliconPNjuncti...
简介:ThetransmissiondelayofphotogeneratedcarriersinaCMOS-process-compatibledoublephotodiode(DPD)isanalyzedbyusingdevicesimulation.TheDPDsmallsignalequivalentcircuitmodelwhichincludestransmissiondelayofphotogeneratedcarriersisgiven.Fromanalysisonthefrequencydomainofthecircuitmodelthedevicehastwopoles.OnehastherelationshipwithjunctioncapacitanceandtheDPD'sload,theotherwiththedepthandthedopingconcentrationoftheN-wellintheDPD.DifferentdepthoftheNwellanddifferentareaoftheDPDswithbandwidthwerecompared.TheanalysisresultsareimportanttodesignthehighspeedDPDs.
简介:Abundanttestdataarerequiredinassessmentofweaponperformance.Whenweapontestdataareinsufficient,Bayesiananalysesinsmallsamplecircumstanceshouldbeconsideredandthetestdatashouldbeprovidedbysimulations.TheseveralBayesianapproachesarediscussedandsomelimitationsarefounded.AnimprovementisputforwardafterlimitationsofBayesianapproachesavailableareanalyzedandtheimprovedapproachisappliedtoassessmentofsomenewweaponperformance.
简介:Thealgorithmofautonomousorbitdeterminationfortheprobearoundsmallbodyisstudied.Inthealgorithm,first,theobservedimagesofthebodyarecomparedwithitspre-computedmodelofthebodytoobtainthelocationofthelimbfeaturesofthebodyintheinertialcoordinate.Second,theinformationoftheimagesandfeaturesinutilizedtoobtainthepositionoftheprobeusingtheLevenberg-Marquardtalgorithm.ThepositionistheninputtoanextendedKalmanfilterwhichdeterminestherealtimeorbitoftheprobe.Finally,consideringtheeffectiveoftheirregularsmallbodyshapeperturbationandthesmallbodymodelparametererrorontheorbitdeterminationprecise,theprocedureofautonomousorbitdeterminationisvalidatedusingdigitalsimulation.
简介:Treetopologies,whichconstructspatialgraphswithlargecharacteristicpathlengthsandsmallclusteringcoefficients,areubiquitousindeploymentsofwirelesssensornetworks.Smallworldsareinvestigatedintree-basednetworks.Duetolinkadditions,characteristicpathlengthsreducerapidlyandclusteringcoefficientsincreasegreatly.Atreeabstract,Cayleytree,isconsideredforthestudyofthenavigationalgorithm,whichrunsautomaticallyinthesmallworldsoftree-basednetworks.Inthefurtherstudy,epidemicsinthesmallworldsoftree-basedwirelesssen-sornetworksonthelargescalearestudied,andthepercolationthresholdiscalculated,atwhichtheoutbreakoftheepidemictakesplace.ComparedwithCayleytree,thereisasmallerpercolationthresholdsufferingfromtheepidemic.
简介:Thispaperpresentsahandheld3Dvision-basedscannerforsmallobjectsbyusingKinect.Itisdifferentfromthepreviouscolor-glove-basedapproacheswhichrequiresegmentingthetargetobject.First,weeliminatethenoisesandtheoutlierscausedbyholdinghands.Second,weapplyKinect-fusionalgorithmandtruncatedsigneddistancefunction(TSDF)torepresent3Dsurfaces.Third,weproposeamodifiedintegrationstrategytoeliminatethehandeffect.Fourth,wetakeadvantageoftheparallelcomputationofGPUsforreal-timeoperation.Themajorcontributionsofthispaperare(1)theregistrationprecisionisimproved,(2)theofflineamendmentandloopclosureoperationarenotrequired,and(3)concave3Dobjectreconstructionisfeasible.IndexTermsHandheld3Dscanning,Kinect-fusion,Truncatedsigneddistancefunction(TSDF).1.IntroductionRecently,thesensor-based3Dmodelreconstructionmethodshavebeenproposed[1].Thesensordeviceshavedifferentpropertiessothatthe3Dreconstructionalgorithmsvaryaccordingly.Thecommonlyusedsensordevicesaretime-of-flight(ToF)cameras[2]-[4],laserscanners[5],andstructuredlightscanners[6],[7].Lasershavegainedareputationforaccuracy;however,caremustbetakentouseeye-safelaserswhenoperatinginproximitytohumans.Foraninteractivesystem,thestructuredlightscannerwhichisbasicallyapassivevision-basedsensordeviceissuperiorbecauseitprovidesa2DdepthimageperframeandismoreaccuratethanthatofaToFcamera.Here,wepresentareal-time3DscannerusingthedepthimagescapturedbyKinect.
简介:Highfrequencysurfacewaveradar(HFSWR)iswellprovedtohaveoverthehorizon(OTH)detectioncapabilitytoweakaerialtargets,suchasconcealedairplanesorcruisemissiles.ThemostimportantproblemofdetectionoffastandsmalltargetsusingHFSWRisearlierwarning,i.e.enlargementofdetectionrangeoftargets.Therefore,thedetectionthresholdshouldbedecreasedaslowaspossible,butnumerousfalsealarmsarebroughtaboutatthesametime.Onthiscondition,conventionaltrackinitiationtechniques,whichnormallyrequiretheprobabilityoffalsealarmtobeatthelevelof10-6,willinitiateenormousfalsetracksandleadtoabnormaloperationoftrackingsystem.Anadaptivemodifiedhoughtransform(AMHT)trackinitiatorisproposedaccordinglyandtherelationofdetectionrangetotheperformanceoftrackinitiatorisanalyzedinthispaper.SimulationsareperformedtoconfirmthecapabilityoftrackinitiationtofastandsmalltargetsindenseclutterbyAMHTtrackinitiator.Thetolerableprobabilityoffalsealarmofdetectorcanreachthelevelof10-3.Anditperformsbetterthantrackinitiatorbasedonmodifiedhoughtransform(MHT).
简介:Aconstructionmethodbasedonthep-planetodesignhigh-girthquasi-cycliclow-densityparity-check(QC-LDPC)codesisproposed.Firstlythegoodpointsineverylineofthep-planecanbeascertainedthroughfilteringthebadpoints,becausethedesignedparity-checkmatrixesusingthesepointshavetheshortcyclesinTannergraphofcodes.Thenoneofthebestpointsfromtheresidualgoodpointsofeverylineinthep-planewillbefound,respectively.Theoptimalpointisalsosingledoutaccordingtothebiterrorrate(BER)performanceoftheQC-LDPCcodesatlast.ExplicitnecessaryandsufficientconditionsfortheQC-LDPCcodestohavenoshortcyclesarepresentedwhichareinfavorofremovingthebadpointsinthep-plane.Sincepreventingtheshortcyclesalsopreventsthesmallstoppingsets,theproposedconstructionmethodalsoleadstoQC-LDPCcodeswithahigherstoppingdistance.
简介:Thetracking,telemetryandcommand(TT&C)missionisextremelyreliableforitscharactersofsmalltimehorizonandhighredundancy.Thecombinedforcingandfailurebiasing(CFFB)methodthatisusuallyusedforsimulatingtheunreliabilityofthehighlydependablemissionsystemseemsnotsoefficientfortheTT&Cmission.TheconceptabouttheimportanceoffailuretransitionisproposedbasedonthelogicalrelationshipbetweenTT&Cmissionanditsinvolvedresources.Then,theimportanceisusedforreadjustingthetransitionrateofthefailuretransitionwhenusingtheforcingandfailurebiasingduringthesimulation.ExamplesshowthattheimprovedCFFBmethodcanevidentlyincreasetheoccurrenceoftheTT&Cmissionfailureeventanddecreasethesamplevariance.MoreredundancyoftheTT&CmissionleadstotheimprovedCFFBmethodmoreefficient.
简介:Givenanon-equidistantsequenceoranequidistantserieswithoneormoreoutliers,agreyinterpolationapproachconsideringthetimelagsisestablishedforproducingthemissingdataorcorrectingtheabnormalvalues.Toaccomplishthis,anewgreyincidencemodel,calledthegreydynamicincidencemodelGDIM(t),isconstructedfordeterminingwhetherthefactorsareeffectivetotheknownfactorandwhatthetimelagisbetweenausefulfactorandthespecifiedsequence.BasedontheresultsoftheGDIM(t)model,twoprogrammingproblemsaredesignedtoobtaintheupperandlowerboundsoftheunknownorabnormalvalueswhichareregardedasgreynumbers.Thesolutionsbasedontheparticleswarmoptimization(PSO)forthenonlinearprogrammingproblemsaregiven.Toexplainhowitcanbeusedinpractice,thisnewgreyinterpolationapproachisappliedtocorrectanabnormalvalueinthesequenceofanagricultureenvironmentproblem.