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.
简介:Thispaperpresentsthedevelopmentofthebloodflowsimulationintwodimensionsovertherealgeometryofthefemoralartery.TheNavier-Stokesequationsaresolvedusingthefiniteelementmethod,toobtainthedistributionsofthebloodpressureandflowvelocityinmultipleinstantsoftimeanddifferentplacesofthefemoralarteryandthusdeterminethecurrentconditionofthebloodvessels.Thevelocityfieldshowsalaminarbehavior,where,thevelocityishigherinthecenterofthearteryanddecreasesasthebloodflowapproachesarterywalls.Inspiteofallarteryandbloodflowpropertiesnotbeingconsidered,thevaluesofpressureandvelocityobtainedarewithinthenormalranges.Finallythemodelisusedtoverifyifthereexistirregularitiesinthebloodflowinbothhealthysubjectsandsickpatients.
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.
简介:Mostimageinterpolationalgorithmscurrentlyusedsuffervisuallytosomeextenttheeffectsofblurrededgesandjaggedartifactsintheimage.Thisletterpresentsanadaptivefeaturepreservingbidirectionalflowprocess,whereaninversediffusionisperformedtoenhanceedgesalongthenormaldirectionstotheiso-photelines(edges),whileanormaldiffusionisdonetoremoveartifacts('jaggies')alongthetangentdirections.Inordertopreserveimagefeaturessuchasedges,anglesandtextures,thenonlineardiffusioncoefficientsarelocallyadjustedaccordingtothefirstorderandthesecondorderdirectionalderivativesoftheimage.ExperimentalresultsontheLenaimagedemonstratethatourinterpolationalgorithmsubstantiallyimprovesthesubjectivequalityoftheinterpolatedimagesoverconventionalinterpolations.
简介:Experimentally,theelectrondrageffectoncarbonnanotubesurfaceinflowingliquidswasinvestigated.Itwasfoundthatelectriccurrentcouldbegeneratedinmetalliccarbonnanotubesimmersedintheliquids.CarbonnanotubesweresynthesizedonSisubstratebyhotfilamentchemicalvapordeposition.Theexperimentalresultsshowedthattheflow-inducedcurrentonthesurfaceofcarbonnanotubefilmswascloselydependedontheflowrate,concentration,propertiesandtemperatureofliquids.Theflow-inducedcurrentwasincreasedwiththeincreasingofflowrate,concentrationandtemperatureofliquids.Theobtainedresultswerediscussedindetail.
简介:Thispaperproposesahybriddecoupledpowerflowmethodforbalancedpowerdistributionsystemswithdistributedgenerationsources.Themethodformulatesthepowerflowequationsinactivepowerandreactivepowerdecoupledformwithpolarcoordinates.Second-ordertermsareincludedintheactivepowermismatchiteration,andconstantJacobianandHessianmatricesareused.Ahybriddirectandindirectsolutiontechniqueisusedtoachieveefficiencyandrobustnessofthealgorithm.Activepowercorrectionissolvedbymeansofasparselowertriangularanduppertriangular(LU)decompositionalgorithmwithpartialpivoting,andthereactivepowercorrectionissolvedbymeansofrestartedgeneralizedminimalresidualalgorithmwithanincompleteLUpre-conditioner.Typicaldistributiongenerationmodelsanddistributionloadmodelsareincluded.Theimpactofzero-impedancebranchesisexplicitlymodeledthroughreconfiguringoftheadjacentbrancheswithimpedances.Numericalexamplesonasampledistributionsystemwithwidespreadphotovoltaicinstallationsaregiventodemonstratetheeffectivenessoftheproposedmethod.
简介:Tostudysimultaneouslocationofdifferentkindsoffacilities,anewmodelofflowinterceptionproblemwithmulti-typeofflowsisproposed,withtheconsiderationofmulti-purposeflowsandtheinfluenceoffacilitiesoneachother.Tobemorepractical,theobjectiveistomaximizethebenefitsfromflow-bycustomersinsteadofmaximizingflowsinthepast.SincethisproblemisNP-hardandthereisnooptimalsolutionforlargenetwork,greedyandimprovedgreedyheuristicalgorithmsareproposed.Acomputationalexampleispresentedtoshowthattheoptimallocationdecisionsareprovedtobestronglydependentontheinfluencecoefficientsandaverageprofitsbyonecustomeranddifferenttypesoffacilitiesarealmostco-located.Finallytheresultsofsensitivityanalysisarereported.
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.
简介:Atpresent,boththepointsourceandtheimagingpolarizationnavigationdevicesonlycanoutputtheangleinformation,whichmeansthatthevelocityinformationofthecarriercannotbeextractedfromthepolarizationfieldpatterndirectly.Opticalflowisanimage-basedmethodforcalculatingthevelocityofpixelpointmovementinanimage.However,forordinaryopticalflow,thedifferenceinpixelvalueaswellasthecalculationaccuracycanbereducedinweaklight.Polarizationimagingtechnologyhastheabilitytoimproveboththedetectionaccuracyandtherecognitionprobabilityofthetargetbecauseitcanacquiretheextrapolarizationmulti-dimensionalinformationoftargetradiationorreflection.Inthispaper,combiningthepolarizationimagingtechniquewiththetraditionalopticalflowalgorithm,apolarizationopticalflowalgorithmisproposed,anditisverifiedthatthepolarizedopticalflowalgorithmhasgoodadaptationinweaklightandcanimprovetheapplicationrangeofpolarizationnavigationsensors.Thisresearchlaysthefoundationfordayandnightall-weatherpolarizationnavigationapplicationsinfuture.
简介:Underthecomplicatedelectromagnetismcircumstance,themodelofdatafusioncontrolandguidanceofsurface-to-airmissileweaponsystemsisestablished.SuchwaysandtheoriesasElman-NN,radartrackingandfilter’sdatafusionnetbasedonthegroupmethodfordata-processing(GMRDF)areappliedtoconstructingthemodelofdatafusion.Thehighlyreliablestateestimationofthetrackingtargetsandtheimprovementinaccuracyofcontrolandguidanceareobtained.Thepurposeisoptimizationdesignofdatafusioncontrolandguidanceofsurface-to-airmissileweaponsystemsandimprovingthefightingeffectivenessofsurface-to-airmissileweaponsystems.
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.
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。