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13 个结果
  • 简介:Thispaperpresentsanewmethodforrobustandaccurateopticalflowestimation.Thesig-nificanceofthisworkistwofold.Firstly,theideaofbi-directionalschemeisadoptedtoreducethemodelerrorofopticalflowequation,whichallowsthesecondorderTaylor'sexpansionofopticalflowequationforaccuratesolutionwithoutmuchextracomputationalburden;Secondly,thispaperestablishsanewopticalflowequationbasedonLSCM(LocalStructureConstancyModel)insteadofBCM(BrightnessConstancyModel),namelytheopticalflowequationdoesnotactonscalarbutontensor-valued(ma-trix-valued)field,duetothetworeason:(1)structuretensor-valuecontainslocalspatialstructureinformation,whichprovidesusmoreuseablecuesforcomputationthanscalar;(2)localimagestructureislesssensitivetoilluminationvariationthanintensity,whichweakensthedisturbanceofnon-uniformilluminationinrealsequences.Qualitativeandquantitativeresultsforsyntheticandreal-worldscenesshowthatthenewmethodcanproduceanaccurateandrobustresults.

  • 标签: 光学流 计算方法 亮度恒定 物理
  • 简介:Thispaperpresentsthedevelopmentofthebloodflowsimulationintwodimensionsovertherealgeometryofthefemoralartery.TheNavier-Stokesequationsaresolvedusingthefiniteelementmethod,toobtainthedistributionsofthebloodpressureandflowvelocityinmultipleinstantsoftimeanddifferentplacesofthefemoralarteryandthusdeterminethecurrentconditionofthebloodvessels.Thevelocityfieldshowsalaminarbehavior,where,thevelocityishigherinthecenterofthearteryanddecreasesasthebloodflowapproachesarterywalls.Inspiteofallarteryandbloodflowpropertiesnotbeingconsidered,thevaluesofpressureandvelocityobtainedarewithinthenormalranges.Finallythemodelisusedtoverifyifthereexistirregularitiesinthebloodflowinbothhealthysubjectsandsickpatients.

  • 标签: BLOOD flow FEMORAL ARTERY finite elements
  • 简介:1供应链管理当今全球已步人经济一体化和因特网新经济时代,市场的变化正在不断加快,需求的不确定性正在不断加大,势必要求信息交换快捷与准确,产品上市快速与及时.原来传统的企业管理模式--"纵向一体化"管理已不适应新时代的要求.

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  • 简介:Mostimageinterpolationalgorithmscurrentlyusedsuffervisuallytosomeextenttheeffectsofblurrededgesandjaggedartifactsintheimage.Thisletterpresentsanadaptivefeaturepreservingbidirectionalflowprocess,whereaninversediffusionisperformedtoenhanceedgesalongthenormaldirectionstotheiso-photelines(edges),whileanormaldiffusionisdonetoremoveartifacts('jaggies')alongthetangentdirections.Inordertopreserveimagefeaturessuchasedges,anglesandtextures,thenonlineardiffusioncoefficientsarelocallyadjustedaccordingtothefirstorderandthesecondorderdirectionalderivativesoftheimage.ExperimentalresultsontheLenaimagedemonstratethatourinterpolationalgorithmsubstantiallyimprovesthesubjectivequalityoftheinterpolatedimagesoverconventionalinterpolations.

  • 标签: 特征保存 双向流程 图象处理 反向流程 插值算法
  • 简介:Experimentally,theelectrondrageffectoncarbonnanotubesurfaceinflowingliquidswasinvestigated.Itwasfoundthatelectriccurrentcouldbegeneratedinmetalliccarbonnanotubesimmersedintheliquids.CarbonnanotubesweresynthesizedonSisubstratebyhotfilamentchemicalvapordeposition.Theexperimentalresultsshowedthattheflow-inducedcurrentonthesurfaceofcarbonnanotubefilmswascloselydependedontheflowrate,concentration,propertiesandtemperatureofliquids.Theflow-inducedcurrentwasincreasedwiththeincreasingofflowrate,concentrationandtemperatureofliquids.Theobtainedresultswerediscussedindetail.

  • 标签: 碳纳米管 电子阻力 CVD 流量传感器
  • 简介:摘要NET平台提供了全面、完整的数据库访问组件,ADO.NET就是在ADO的基础上发展而来,全面支持以面向对象的形式来访问和管理数据库系统,文中主要以信息管理系统研发为例,探讨了.NET开发平台下的数据库技术以及ADO.NET技术访问和存取数据库的模式。ADO.NET组件实现了一种全新的数据库访问、存取机制。

  • 标签: NET框架 ADO.NET 组件 数据库访问 信息管理系统
  • 简介:Thispaperproposesahybriddecoupledpowerflowmethodforbalancedpowerdistributionsystemswithdistributedgenerationsources.Themethodformulatesthepowerflowequationsinactivepowerandreactivepowerdecoupledformwithpolarcoordinates.Second-ordertermsareincludedintheactivepowermismatchiteration,andconstantJacobianandHessianmatricesareused.Ahybriddirectandindirectsolutiontechniqueisusedtoachieveefficiencyandrobustnessofthealgorithm.Activepowercorrectionissolvedbymeansofasparselowertriangularanduppertriangular(LU)decompositionalgorithmwithpartialpivoting,andthereactivepowercorrectionissolvedbymeansofrestartedgeneralizedminimalresidualalgorithmwithanincompleteLUpre-conditioner.Typicaldistributiongenerationmodelsanddistributionloadmodelsareincluded.Theimpactofzero-impedancebranchesisexplicitlymodeledthroughreconfiguringoftheadjacentbrancheswithimpedances.Numericalexamplesonasampledistributionsystemwithwidespreadphotovoltaicinstallationsaregiventodemonstratetheeffectivenessoftheproposedmethod.

  • 标签: 功率流方法 配电系统 混合 解耦 HESSIAN矩阵 JACOBIAN
  • 简介:Tostudysimultaneouslocationofdifferentkindsoffacilities,anewmodelofflowinterceptionproblemwithmulti-typeofflowsisproposed,withtheconsiderationofmulti-purposeflowsandtheinfluenceoffacilitiesoneachother.Tobemorepractical,theobjectiveistomaximizethebenefitsfromflow-bycustomersinsteadofmaximizingflowsinthepast.SincethisproblemisNP-hardandthereisnooptimalsolutionforlargenetwork,greedyandimprovedgreedyheuristicalgorithmsareproposed.Acomputationalexampleispresentedtoshowthattheoptimallocationdecisionsareprovedtobestronglydependentontheinfluencecoefficientsandaverageprofitsbyonecustomeranddifferenttypesoffacilitiesarealmostco-located.Finallytheresultsofsensitivityanalysisarereported.

  • 标签: 侦察问题 电子对抗 干扰 NP问题
  • 简介:CognitiveRadio(CR)systembasedonOrthogonalFrequencyDivisionMultipleAccess(OFDMA),suchasWirelessRegionalAreaNetworks(WRAN)andWorldwideInteroperabilityforMicrowaveAccess(WiMAX),oftenattempttoimproveperformanceviadynamicradioresourcemanagement,whichischaracterizedasconcurrentprocessingofdifferenttrafficandnondeterministicsystemcapacity.Itisessentialtodesignandevaluatesuchcomplexsystemusingpropermodelingandanalysistools.Inthepreviouswork,mostofthecommunicationsystemsweremodeledasMarkovChain(MC)andStochasticPetriNets(SPN),whichhavetheexplicitlimitationinevaluatingadaptiveOFDMACRsystemwithwideareatraffic.Inthispaper,wedevelopanexecutabletop-downhier-archicalColoredPetriNet(CPN)modelforadaptiveOFDMACRsystem,andanalyzeitsperformanceusingCPNtools.TheresultsdemonstratethattheCPNcanmodeldifferentradioresourcemanage-mentalgorithmsinCRSystems,andtheCPNtoolsrequirelesscomputationaleffortthanMarkovmodelusingMatlab,withitsflexibilityandadaptabilitytothetrafficswhicharrivalintervalandprocessingtimearenotexponentiallydistributed.

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  • 简介:Atpresent,boththepointsourceandtheimagingpolarizationnavigationdevicesonlycanoutputtheangleinformation,whichmeansthatthevelocityinformationofthecarriercannotbeextractedfromthepolarizationfieldpatterndirectly.Opticalflowisanimage-basedmethodforcalculatingthevelocityofpixelpointmovementinanimage.However,forordinaryopticalflow,thedifferenceinpixelvalueaswellasthecalculationaccuracycanbereducedinweaklight.Polarizationimagingtechnologyhastheabilitytoimproveboththedetectionaccuracyandtherecognitionprobabilityofthetargetbecauseitcanacquiretheextrapolarizationmulti-dimensionalinformationoftargetradiationorreflection.Inthispaper,combiningthepolarizationimagingtechniquewiththetraditionalopticalflowalgorithm,apolarizationopticalflowalgorithmisproposed,anditisverifiedthatthepolarizedopticalflowalgorithmhasgoodadaptationinweaklightandcanimprovetheapplicationrangeofpolarizationnavigationsensors.Thisresearchlaysthefoundationfordayandnightall-weatherpolarizationnavigationapplicationsinfuture.

  • 标签: POLARIZED optical flow algorithm IMAGING BIONIC
  • 简介:Underthecomplicatedelectromagnetismcircumstance,themodelofdatafusioncontrolandguidanceofsurface-to-airmissileweaponsystemsisestablished.SuchwaysandtheoriesasElman-NN,radartrackingandfilter’sdatafusionnetbasedonthegroupmethodfordata-processing(GMRDF)areappliedtoconstructingthemodelofdatafusion.Thehighlyreliablestateestimationofthetrackingtargetsandtheimprovementinaccuracyofcontrolandguidanceareobtained.Thepurposeisoptimizationdesignofdatafusioncontrolandguidanceofsurface-to-airmissileweaponsystemsandimprovingthefightingeffectivenessofsurface-to-airmissileweaponsystems.

  • 标签: 空气导弹 熔解技术 神经网络 控制理论
  • 简介:Classicalnetworkreliabilityproblemsassumebothnetworksandcomponentshaveonlybinarystates,fullyworkingorfullyfailedstates.Butmanyactualnetworksaremulti-state,suchascommunicationnetworksandtransportationnetworks.Thenodesandarcsinthenetworksmaybeinintermediatestateswhicharenotfullyworkingeitherfullyfailed.Asimulationapproachforcomputingthetwo-terminalreliabilityofamulti-statenetworkisdescribed.Two-terminalreliabilityisdefinedastheprobabilitythatdunitsofdemandcanbesuppliedfromthesourcetosinknodesunderthetimethresholdT.Thecapacitiesofarcsmaybeinastochasticstatefollowinganydiscreteorcontinuousdistribution.Thetransmissiontimeofeacharcisalsonotafixednumberbutstochasticaccordingtoitscurrentcapacityanddemand.Tosolvethisproblem,acapacitatedstochasticcolouredPetrinetisproposedformodellingthesystembehaviour.Placesandtransitionsrespectivelystandforthenodesandarcsofanetwork.Capacitatedtransitionandself-modifiedtokencolourwithrouteinformationaredefinedtodescribethemulti-statenetwork.Bythesimulation,thetwo-terminalreliabilityandnodeimportancecanbeestimatedandtheoptimalroutewhosereliabilityishighestcanalsobegiven.Finally,twoexamplesofdifferentkindsofmultistatenetworksaregiven.

  • 标签: 有色PETRI网 可靠性问题 多态网络 能力约束 随机 终端
  • 简介:为了提高OpenFlow的通讯质量,控制了所有光的网络,光signal-to-noise比率全面了解(OSNR-CA)为基于的lightpath控制建模计划被建议。这条途径把主要物理层的光缺陷转变成OSNR价值,并且沿着lightpath考虑光信号的这全面OSNR值,当用开流动的协议为连接请求建立lightpath时。而且,建议计划做在每个节点监视功能的OSNR的完整的优点,并且由扩大OpenFlow协议的消息根据comprehensive-OSNR价值分配lightpath,以便保证lightpath的可靠建立。模拟结果证明建议计划以包损失率和lightpath建立时间有更好的性能。

  • 标签: OSNR 全光网络 流量控制 光路 感知模型 控制系统