学科分类
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347 个结果
  • 简介:[1]CaoYY,LamsJ.RobustH∞ControlofUncertainMarkovianJumpSystemswithTime-Delay.IEEETrans.Automat.Contr.,2000,45(1):77~83.[2]DoyleJC,Glover,KhargonekarPP,etal.State-SpaceSolutionstoStandardH2andH∞ControlProblems.IEEETrans.Automat.Contr.,1989,34(8):831~847.[3]FridmanE,ShakedU.H∞-normandInvariantManifoldsofSystemswithStateDelays.Sys.&Contr.Lett.,1999,36(2):157~165.[4]GeJ,FrankPM,LinCF.RobustH∞StateFeedbackControlforLinearSystemswithStateDelayandParameterUncertainty.Automatica,1996,32(6):1183~1185.[5]HirataM,LiuKZ,SatoT,etal.ASolvabilityConditionofanExtendedH∞ControlProblemUsingRiccatiInequalities.Int.J.Contr.,2000,73(4):265~275.[6]HmamedA.FurtherResultsontheRobustStabilityofUncertainTime-DelaySystems.Int.J.Syst.Sci.,1991,22(3):605~619.[7]IwasakiT,Skelton,E.AllControllersfortheGeneralH∞ControlProblem:LMIExistingConditionsandState-SpaceFormulas.Automatica,1994,42(7):1307~1317.[8]LeeB,LeeJG.RobustStabilizationofLinearDelayedSystemswithStructuredUncertainty.Automatica,1999,35(6):1149~1154.[9]LeeKH,MoonYS,KwonWH.RobustStabilityAnalysisofParametricUncertainTime-DelaySystems.InProceedingofIEEEConferenceonDecisionandControl,Tampa,FL,1998:1346~1352.[10]LehmanB,KhalilS.DelayIndependentStabilityConditionsandDecayEstimatesforTime-VaryingFunctional.IEEETrans.Automat.Contr.,1994,39(8):1673~1676.[11]MahmoudMS,Al-MuthairiNF.DesignofRobustControllersforTime-DelaySystems.IEEETrans.Automat.Contr.,1994,39(2):159~161.[12]MoriETN,KuwaharaM.AwaytoStabilizeLinearSystemswithDelayedState.Automatica,1983,19(5):571~573.[13]NiculescuSI,andAnnasuamyAM.ASimpleAdaptiveControllerforPositive-RealSystemswithTime-Delay.ProceedingoftheAmericanControlConference,Chicago,Illi

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  • 简介:HandoverinDigitalVideoBroadcastingforHandhelds(DVB-H)aimstoprovidecontinuousmobilebroadcastingserviceswhenauseristravelingthroughcellboundaries.Agoodhandovercontrolcanimprovethepowerefficiencyandgainmuchbetterreceptionquality.ThisletterprovidesanovelapproachforDVB-HhandoverbasedonDVB-H/UniversalMobileTelecommunicationsSystem(UMTS)hybridnetwork,whichmovesthemainhandoverfunctionfromtheterminalstothenetworks,sothatitreducestheoperationcomplexityoftheterminalsandincreasesthepowersaving.WhentheterminalcannotreceivetheDVB-Hsignalinthetransmissionshadowareasorbecauseofsomeotherreasons,theUMTSnetworksmayofferthesameservicetouserstomaketheservicecontinuous.AstheUMTSnetworkshavethetopologyoftheDVB-Hnetworks,bycommunicatingwiththeterminals,theUMTSnetworkscanhelptheterminalstopredictthehandover,andavoidunnecessaryhandover.

  • 标签: 数字视频广播 移动通信系统 移交控制 通信技术
  • 简介:Thea-Si∶H/SiNx∶HsampleseriesareinvestigatedbymeansofRamanscatteringtechnique(RST).Theresultshowsthatduetothestructuralmismatchbetweena-Si∶Handa-SiNx∶H,severeinduceddistortionsareproducedintheinterfaceoftheheterojunction,andtheseinduceddistortionstendtowardsacertainenergystate.Theorderingoftheinterfacestructuredependsontheperiodicnumberofmultilayerthinfilms.

  • 标签: Multilayer films Heterojunction Interface region INDUCED
  • 简介:Theproblemoftherobustfaultdetectionfilterdesignfortime-varyingdelaysswitchedsystemsisconsideredintheframeworkofmixedH_-/H_∞.Firstly,theweightedH_∞performanceindexisutilizedastherobustnessperformance,andtheH_-indexisusedasthesensitivityperformanceforobtainingtherobustfaultdetectionfilter.ThenanovelmultipleLyapunov-Krasovskiifunctionisproposedforderivingsufficientexistenceconditionsoftherobustfaultdetectionfilterbasedontheaveragedwelltimetechnique.Byintroducingslackmatrixvariable,thecouplingbetweentheLyapunovmatrixandsystemmatrixisremoved,andtheconservatismofresultsisreduced.Basedontherobustfaultdetectionfilter,residualisgeneratedandevaluatedfordetectingfaults.Inaddition,theresultsofthispaperaredependentontimedelays,andrepresentedintheformoflinearmatrixinequalities.Finally,thesimulationexampleverifiestheeffectivenessoftheproposedmethod.

  • 标签: 故障检测滤波器 切换系统 时变时滞 滤波器设计 线性矩阵不等式 LYAPUNOV
  • 简介:TherobustH∞controlfornetworkedcontrolsystemswithbothstochasticnetwork-induceddelayanddatapacketdropoutisstudied.Whendataaretransmittedovernetwork,thestochasticdatapacketdropoutprocesscanbedescribedbyatwo-stateMarkovchain.Thenetworkedcontrolsystemswithstochasticnetwork-induceddelayanddatapacketdropoutaremodeledasadiscretetimeMarkovjumplinearsystemwithtwooperationmodes.ThesuffcientconditionofrobustH∞controlfornetworkedcontrolsystemsstabilizedbystatefeedbackcontrollerispresentedintermsoflinearmatrixinequality.Thestatefeedbackcontrollercanbeconstructedviathesolutionofasetoflinearmatrixinequalities.Anexampleisgiventoverifytheeffectivenessofthemethodproposed.

  • 标签: 网络控制系统 H∞控制 线性系统 神经网络
  • 简介:Aconductionchannelmodelispropsedtoexplainthehighconductivitypropertyofnc-Si:H.Detailedenergybanddiagramisdevelopedbasedontheanalysisandcalculation,andtheconductivityofthenc-Si:Hwasthenanalysedonthebasisofenergybandtheory.Itisassumedthattheconductivityofthenc-Si:Hstemsfromtwoparts:theconductanceoftheinterface,wherethetransportmechanismisidentifiedasathermal-assistedtunnelingprocess,andtheconductancealongthechannelaroundthegrain,whichmainlydeterminedthehighconductivityofthenc-Si:H.Theconductivityofnc-Si:Hiscalculatedandcomparedwiththeexperimentdata.Thetheoryisinagreementwiththeexperiment.

  • 标签: 传导率 能带图 片状晶体硅
  • 简介:Ananalysisisgiventoexplaintheinstabilityofthehighconductivitypropertyofnc-Si:Hfabricated.Detaileddiscussioniscarriedoutconcentratingontheconductivityandgrowthmechanism.Itisassumedthattheinstabilityoftheconductivityofthenc-Si:Hstemsfromtwopart:thephasetransitionfromnanocrystallitesintoa-Si:H,andtheoxygenincorporationofthethinlayerofthefilm,whichcontributesmoretotheeffectwhenthefilmsufferstheexposuretoair.Thetheoryisinagreementwiththeexperimentandmeasurement.

  • 标签: 导电率 不稳定性 硅薄膜
  • 简介:ThisletterproposesaratecontrolalgorithmforH.264videoencoder,whichisbasedonblockactivityandbufferstate.ExperimentalresultsindicatethatithasanexcellentperformancebyprovidingmuchaccuratebitrateandbettercodingefficiencycomparedwithH.264.ThecomputationalcomplexityofthealgorithmisreducedbyadoptinganovelblockactivitydescriptionmethodusingtheSumofAbsoluteDifference(SAD)of16×16mode,anditsrobustnessisenhancedbyintroducingafeedbackcircuitatframelayer.

  • 标签: 视频编码 H.264标准 速率控制 MPEG
  • 简介:Photoluminescenceevaluationofpandntype6H-SiCsampleshasbeendone.Resultsshowthatatlowtemperaturethephotoluminescenceof6H-SiCisclearlydominatedbydonor-acceptorpairtransitions,insomecase,free-to-donortransitioncouldbeobservedathighertemperature.Thethermalquenchingprocessesofthephotoluminescencehavebeeninvestigatedtodeterminethepossibleionizationnenergiesoftheimpurities.

  • 标签: 光致发光 估算 碳化硅
  • 简介:Theholeinjection,theradiativerecombinationandthedevicelumi-nescentefficienciesofamorphoussiliconcarbidethinfilmp-I-njunctionlightemit-tingdiodesarequantitativelycalculated,andtheeffectofthecarrier(especiallythehole)injectionandrecombinationprocessesonthedeviceluminescentcharacteris-ticsarerevealed.Withoutconsideringthedevicejunctiontemperature,itisroundthatthedeviceluminescentefficiencymainlydependsontheholeinjectionefficiencyatlowfieldandtheholeradiativerecombinationefficiencyathighfieldrespective-ly.Thetheoreticalanalysesareinwellagreementwiththeexperimentalresults.

  • 标签: 发光二极管 碳化硅 薄膜 注入系数
  • 简介:TherobustHoocontrolproblemforuncertainstochastictime-delaysystemscontainingnonlinearactuatorsisconsidered.Theuncertaintiesinthesystemsareassumedtosatisfyspecificmatchcondition.Thetimedelaysexitstinstateaswellascontrolinput.Thenewstochasticrobuststabilizationcriterionandasufficientconditionfortheexistenceofstochasticrobuststabilizingcontrollawarederived.Thedday-independentmemorylessrobustH∞controllersareconstructedtostabilizethegivensystemsintermsofagroupoflinearmatrixinequalities.Anumericalsimulationexampleispresentedtoshowthattheproposedapproachisvalid.

  • 标签: 随机延时 LMI 状态反馈 饱和非线性机构 H∞控制
  • 简介:为了对大规模军事知识资源分类管理,提出了一种基于知识地图的文本分类(KMTC)方法。将知识地图划分成层次社区结构,构建了知识地图的社区结构树,社区结构树的节点具有主题聚集属性,可作为文本按主题分类的依据;基于知识单元进行文本特征向量提取,并引入复杂网络的度中心度概念,计算文本对应的特征向量值。与传统文本分类方法相比,将收集整理的军事领域文本作为训练文本集合进行试验验证,提高了文本分类准确性。

  • 标签: 文本分类 知识地图 社区结构 特征提取
  • 简介:所谓移动通信指的是通信双方至少有一方在移动中或者停留在某个非预定位置上进行信息传输和交换。随着社会、经济的高速发展,移动通信已经在人们日常生活中占据了重要地位,因此,我们有必要对它加以了解。

  • 标签: 移动通信 发展史 业务类型 信号形式 蜂窝通信 TDMA
  • 简介:ThispaperstudiestherobuststochasticstabilizationandrobustH∞controlforlineartime-delaysystemswithbothMarkovianjumpparametersandunknownnorm-boundedparameteruncertainties.ThisproblemcanbesolvedonthebasisofstochasticLyapunovapproachandlinearmatrixinequality(LMI)technique.SufficientconditionsfortheexistenceofstochasticstabilizationandrobustH∞statefeedbackcontrollerarepresentedintermsofasetofsolutionsofcoupledLMIs.Finally,anumericalexampleisincludedtodemonstratethepracticabilityoftheproposedmethods.

  • 标签: Markovian JUMP parameter STOCHASTIC stabilization Robust
  • 简介:简要介绍了H.265/HEVC的编码框架和采用的新技术。比较了H.264/AVC和H.265/HEVC的图像质量、压缩比、编码时延等关键技术指标,将H.265/HEVC与H.264/AVC的编码性能进行了比较。实验结果表明,HEVC在编码性能上有了明显提高。

  • 标签: 视频编码 H.265/HEVC 性能评估
  • 简介:Inthispaper,afuzzyreasoningbasedtemporalerrorconcealmentmethodisproposed.ThebasictemporalerrorconcealmentisimplementedbyestimatingMotionVector(MV)ofthelostMacroBlock(MB)fromitsneighboringMVs.WhichMVisthemostproperoneisevaluatedbysomecriteria.Generally,twocriteriaarewidelyused,namelySideMatchDistortion(SMD)andSumofAbsoluteDifference(SAD)ofcorrespondingMV.However,eachcriterioncouldonlypartlydescribethestatusoflostblock.Toaccomplishthejudgementmoreaccurately,thetwomeasuresareconsideredtogether.ThusarefinedmeasurebasedonfuzzyreasoningisadoptedtobalancetheeffectsofSMDandSAD.TermsSMDandSADareregardedasfuzzyinputandtheterm‘similarity’asoutputtocompletefuzzyreasoning.ResultoffuzzyreasoningrepresentshowthetestedMVissimilartotheoriginalone.Andk-meansclusteringtechniqueisperformedtodefinethemembershipfunctionofinputfuzzysetsadaptively.Accordingtotheexperimentalresults,theconcealmentbasedonnewmeasureachievesbetterperformance.

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  • 简介:Thephotocurrent-voltagecharacteristicsandphotoelectricsensitivityofa-Si:Hsampleswithslitandcombelectrodesaremeasured.Amethodforcalculatingthechargeintensifyinggainfromthephotoelectricsensitivityisproposed.Theobtainedchargeintensifyinggainofa-Si:Hunderanelectricfieldof105V/cmthroughthismethodisashighas4.3×103.Thegenerationprocessofthechargeintensificationeffectina-Si:Hisdiscussedonthebasisoftheenergyleveldiagram.Andtheproductofelectron’smobilityanditslifetimeiscalculatedfromthemeasuredvaluesofthegains.

  • 标签: A-SI:H semiconductor CHARGE INTENSIFICATION EFFECT PHOTOELECTRIC