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简介：Inthispaper,thefeedbackloadreductionprobleminwirelesssystemsbasedonorthogonalfrequencydivisionmultiplexing(OFDM)isinvestigatedandanopportunisticfeedbackscheme(OFS)isproposed.ThekeyideabehindOFSisthatonlythekeychannelgainswhichcansignificantlyaffectthesystemthroughputarefedbacktotheBS.Firstly,thekeychannelgainsareprovedtobelongtoachannelgaininterval.Secondly,astatisticalmethodisproposedtoestimatethechannelgaininterval.Thirdly,theopportunisticfeedbackschemeisformulatedandthefeedbackloadofOFSisanalyzed.TheadvantageofOFSisthreefold:thefirstisOFScanworkinbothOFDM-basedmulticastsystemandOFDM-basedunicastsystem.ThesecondisthechannelfadingtypeoftheBS-userlinkisnotrequired,whichismorerealistic.ThethirdisOFScangetbetterfeedbackloadperformancecomparedwithotherschemes,whileachievingalmostthesamethroughputperformancecomparedwiththatoffullfeedbackscheme.

简介：Inthispaper,theauthorsdesignboundaryfeedbackcontrollersattheinteriornodetostabilizeastar-shapednetworkofEuler-Bernoullibeams.Thebeamsarepinnedeachother,thatis,thedisplacementsofthestructurearecontinuousbuttherotationsofthebeamsarenotcontinuous.Thewell-posed-nessoftheclosedloopsystemisprovedbythesemigrouptheory.Theauthorsshowthatthesystemisasymptoticallystableiftheauthorsimposeabendingmomentcontroloneachedge.Finally,theauthorsderivetheexponentialstabilityofthesystem.

简介：Inthispaper,theglobalasymptoticstabilizationbyoutputfeedbackisinvestigatedforaclassofuncertainnonlinearsystemswithunmeasuredstatesdependentgrowth.Comparedwiththecloselyrelatedworks,theremarkablenessofthepaperisthateitherthegrowthrateisanunknownconstantorthedimensionoftheclosed-loopsystemissignificantlyreduced,mainlyduetotheintroductionofadistinctdynamichigh-gainobserverbasedonanewupdatinglaw.Motivatedbytherelatedstabilizationresults,andbyskillfullyusingthemethodsofuniversalcontrolandbackstepping,weobtainthedesignschemetoanadaptiveoutput-feedbackstabilizingcontrollertoguaranteetheglobalasymptoticstabilityoftheresultingclosed-loopsystem.Additionally,anumericalexampleisconsideredtodemonstratetheeffectivenessoftheproposedmethod.

简介：Thispaperisconcernedwiththeglobalstabilizationviaoutput-feedbackforaclassofhigh-orderstochasticnonlinearsystemswithunmeasurablestatesdependentgrowthanduncertaincontrolcoefficients.Indeed,therehavebeenabundantdeterministicresultswhichrecentlyinspiredtheintenseinvestigationfortheirstochasticanalogous.However,becauseofthepossibilityofnon-uniquesolutionstothesystems,therelackbasicconceptsandtheoremsfortheproblemunderinvestigation.Firstofall,twostochasticstabilityconceptsaregeneralizedtoallowthestochasticsystemswithmorethanonesolution,andakeytheoremisgiventoprovidethesufficientconditionsforthestochasticstabilitiesinaweakersense.Then,byintroducingthesuitablereducedorderobserverandappropriatecontrolLyapunovfunctions,andbyusingthemethodofaddingapowerintegrator,acontinuous（nonsmooth）output-feedbackcontrollerissuccessfullydesigned,whichguaranteesthattheclosed-loopsystemisgloballyasymptoticallystableinprobability.

简介：Thepapermainlystudiesthesum-rateperformanceoflimitedfeedback(LFB)block-diagonalization(BD)inmulti-userdistributedantennasystem(DAS).Asthechannelstateinformation(CSI)fedbacktobasestation(BS)islimited,multi-userinterference(MUI)iscausedinevitablybecauseofthequantizationerror.ConsideringtheinfluenceoftheMUItothecapacityofDAS,weproposeaparameterofeffectivesum-rateratio(ESRR)todenotethecapacityoffsetundertheconditionoftheBScangetperfectCSIandlimitedCSIfirst,thenweconfirmthattheapproximatedESRRisveryclosetoactualESRRgotthroughsimulations.Afterthat,basedontheapproximatedESRR,anadaptiveminimumbitfeedbackschemewhichcaneffectivelyreducetheoverheadoffeedbackchannelandthecomplexityofthesystemisproposed.Simulationresultsshowtheeffectivenessoftheproposedscheme.

简介：Controlofthespatiotemporalpatternsnearthecodimension-threeTuring–Hopf–Wavebifurcationsisstudiedbyusingtime-delayedfeedbackinathree-variableBrusselatormodel.LinearstabilityanalysisofthesystemshowsthatthecompetitionamongtheTuring-,Hopf-andWave-modes,thewavenumber,andtheoscillationfrequencyofpatternscanbecontrolledbychangingthefeedbackparameters.TheroleofthefeedbackintensityPuplayedoncontrollingthepatterncompetitionisequivalenttothatofPw,butoppositetothatofPv.TheroleofthefeedbackintensityPuplayedoncontrollingthewavenumberandoscillationfrequencyofpatternsisequivalenttothatofPv,butoppositetothatofPw.Whentheintensitiesoffeedbackareappliedequally,changingthedelayedtimecouldnotalterthecompetitionamongthesemodes,however,itcancontroltheoscillationfrequencyofpatterns.Theanalyticalresultsareverifiedbytwo-dimensional(2D)numericalsimulations.