简介:Thisarticleisconcernedwiththemodelingandcontrolproblemsoftheflexiblespacecraft.First,thestateobserverisdesignedtoestimatethevibrationmodeonthebasisoffreevibrationmodels.Then,anoptimalguaranteedcostcontrollerisproposedtostabilizesystemattitudeanddampthevibrationoftheflexiblebeamatthesametime.Numericalsimulationexamplesshowthefeasibilityandvalidityoftheproposedmethod.
简介:WirelessM-BusaccordingtoEN-13757-4isamajorcontenderforlocalmetrologicalnetwork(LMN)insmartmeteringandsmartgridapplications,asitholdsthepromiseofflexibleandoptimizedsolutions.ItenjoyswidepopularityincontinentalEurope,butincreasinglyinmanyotherregionsoftheworld.However,WirelessM-Busischaracterizedbyawidevarietyofdifferentoperationmodes(C-,F-,N-,P-,Q-,R-,S-,andT-modes),whichworkindifferentfrequencybands(i.e.,868MHz,433MHz,and169MHz).Itsapplicationlayercanbeenhancedbyextensions,beingdefinedfromvendoralliances,liketheOpenMeteringSystem(OMS)Group,orfromnationalbodies.Thiscontributiondescribesrequirements,designtechniques,andexperiencesfromthedevelopmentofhighlyefficientWirelessM-Busprotocolstacks,whichalsosupportgoodflexibility,efficiency,andportabilitywithregardtomicrocontrollerandRF-transceiverplatforms.Thepresentedapproachisnotlimitedtotheuseofmodernsoftwareengineeringdesignprocesses,butalsoincludesessentialadditionalfeaturesliketestingandsimulation,aswellastoolsforcommissioningandmonitoring.
简介:提出了一种新的恒虚警检测算法SOSGO-CFAR。该算法应用检测单元采样作为选择参考单元的依据,使用了基于转换恒虚警(S-CFAR)和排序选大恒虚警(OSGO—CFAR)的复合算法。文章给出了该算法在均匀背景中的数学分析。并在均匀背景、杂波边缘和多目标情况下,用MonteCarlo方法进行了仿真分析。结果表明,该检测器既具有均匀背景下和CA-CFAR相近的良好性能,在杂波边缘环境中,具有接近OSGO-CFAR的性能,且在多目标环境中,其性能明显好于S-CFAR。
简介:Silvernanowires(AgNWs)withdiameterof90--150nmandlengthof20--50μmweresuccessfullysynthesizedbyapolyolprocess.Grapheneoxide(GO)waspreparedbyHummersmethod,andwasreducedwithstronghydrazinehy-drateatroomtemperature.Theflexibletransparentconductivefilms(TCFs)werefabricatedusingthemixedcelluloseeater(MCE)asmatrixandAgNWsandreducedgrapheneoxide(rGO)asconductivefillersbytheimprovedvacuumfiltrationprocess.Then,theoptical,electricalandmechanicalpropertiesoftheAgNWs-rGOfilmswereinvestigated.TheresultsshowthatfortheAgNWs-rGOfilmproducedwiththedepositiondensitiesofAgNWsandrGOas110mg.m2and55mg·m^-2,theopticaltransmissionat550nmis88.4%withRsaround891Ω·sql,whereastheopti-caltransmissionfortheAgNWs-rGOfilmwithdepositiondensitiesofAgNWsandrGOof385mg·m^-2and55mg·m^-2is79.0%at550nmwithRsaround9.6Ω·sql.ThereislittleovertincreaseinRsoftheAgNWS-rGOfilmaftertapetestsfor200times.ThebendingtestresultsindicatethatthechangeinRsofAgNWs-MCEfilmislessthan2%evenafter200cyclesofcompressiveortensilebending.TheexcellentmechanicalpropertiesoftheAgNWs-rGOfilmcanbeattributedtotheburyingofAgNWsandrGOatthesurfaceofMCE.
简介:Toolmanagementisnotasingle,simpleactivity,itiscomprisedofacomplexsetoffunctions,especiallyinaflexiblemanufacturingsystem(FMS)environment.Theissuesassociatedwithtoolmanagementincludetoolrequirementplanning,toolreal-timescheduling,toolcribmanagement,toolinventorycontrol,toolfaultdiagnosis,tooltrackingandtoolmonitoring.Inordertomaketoolsflowinto/outofFMSefficiently,thisworkisaimedtodesignaknowledge-baseddecisionsupportsystem(KBDSS)fortoolmanagementinFMS.Firstlyanoverviewoftoolmanagementfunctionsisdescribed.ThenthestructureofKBDSSfortoolmanagementandtheessentialagentsinthedesignofKBDSSarepresented.FinallytheindividualagentsofKBDSSarediscussedfordesignanddevelopment.
简介:Weexperimentallydemonstratethemultiplesignalmodulationonasingleclass10Gverticalcavitysurfaceemittinglaser(VCSEL)carrierat1310nmfornextgenerationmulticast-enableddatacenternetworks.A10Gbit/sdatasignalisdirectlymodulatedontoasinglemodeVCSELcarrier.Tomaximizecarrierspectralefficiency,a2GHzreferencefrequency(RF)clocktoneissimultaneouslymodulatedontheVCSELphaseattribute.TheinherentVCSELorthogonalpolarizationbistabilitywithchangingbiascurrentisfurtherexploitedintransmissionofapolarizationbasedpulsepersecond(PPS)timingclocksignal.Therefore,wesimultaneouslytransmita10Gbit/sdirectlymodulateddata,2GHzphasemodulatedRFandapolarization-basedPPSclocksignalsusingasinglemode10GHzbandwidthVCSELcarrier.Itisthefirsttimethatasingleclass10GVCSELcarrierisreportedtotransmitadirectlymodulateddata,phasemodulatedRFclockandpolarizationbasedPPStimingsignalsimultaneouslyinasinglewavelength.AofG.652singlemodefibre(SMF)transmissionover3.21kmisexperimentallyattained.Areceiversensitivityof-15.60dBmisexperimentallyobtainedforthedirectlymodulated10Gbit/sdatasignal.A3.21-km-longSMFtransmissionintroducesapenaltyof0.23dBtothedatasignal.Thecontributionofa2GHzphasemodulatedRFandapolarization-basedPPSclocksignaltothispenaltyisfoundtobe0.03dB.AnRFsingle-sideband(SSB)phasenoisevaluesof-82.36dBc/Hzand-77.97dBc/Hzareattainedwithoutandwithsimultaneousdirectlymodulateddataandpolarization-basedPPSclocksignalsrespectivelyfora3.21-km-longSMFtransmission.Thisworkprovidesanalternativeefficientandcosteffectivetechniqueforsimultaneoushigh-speedmultipleinformationtransmissiontodifferentnetworknodeswithinadatacenternetworkthroughsharednetworkinfrastructure.
简介:UnipolarresistiveswitchingbehaviorsoftheZnOandAl2O3/ZnOfilmsfabricatedonflexiblesubstratesbypulselaserdepositionwerestudiedinthispaper.Thefilmsweredepositedatroomtemperaturewithoutpost-annealingtreatmentduringtheprocess.XraydiffractionresultsindicatedthatZnOfilmhasadominantpeakat(002).ScanningelectronmicroscopyobservationshowedacolumnargrainstructureoftheZnOfilmtothesubstrate.ThebilayerdeviceofAl2O3/ZnOfilmshadstableresistiveswitchingbehaviorswithagoodenduranceperformanceofmorethan200cycles,highresistiveswitchingratioofover103atareadvoltageof0.1V,whichisbetterthanthatofthesingleoxidelayerdeviceofZnOfilm.Apossibleresistiveswitchingfilamentarymodewasdemonstratedinthispaper.TheconductionmechanismsofhighandlowresistancestatescanbeexplainedbyspacechargelimitedconductionandOhmic’sbehaviors.Theenduranceofthebilayer(BL)devicewasnotdegradeduponbendingcycles,whichindicatesthepotentialoftheflexibleresistiveswitchingrandomaccessmemoryapplications.