简介:Inthispaper,weformulateasingle-speciesmodelofcontraceptioncontrolwithwhitenoiseonthedeathrate.Firstly,theuniquenessofglobalpositivesolutionofthemodelisproved.Secondly,uniformlyboundedmeanofsolutionisobtainedbyusingtheLiyapunovfunctionandChebyshevinequality.Lastly,stochasticglobalasymptoticstabilityofzeroequilibriumsisanalyzed.
简介:Ahybridcontrolplatformisinvestigatedinthispapertomitigatemicrovibrationstoagroupofvibrationsensitiveequipmentinstalledinamicroelectronicsfacilitysubjecttonearbyroadvehicle-inducedhorizontalandverticalgroundmotions.Thehybridcontrolplatform,onwhichmicroelectronicsequipmentisinstalled,ismountedonabuildingfloorthroughaseriesofpassivemountsandcontrolledbyhydraulicactuatorsinbothhorizontalandverticaldirections.Thecontrolplatformisanelasticbodywithsignificantbendingmodesofvibration,andasub-optimalcontrolalgorithmisusedtomanipulatethehydraulicactuatorswithactuatordynamicsincluded.Thefiniteelementmodelandtheequationsofmotionofthecoupledplatform-buildingsystemarethenestablishedintheabsolutecoordinatetofacilitatethefeedbackcontrolandperformanceevaluationoftheplatform.Thehorizontalandverticalgroundvibrationsatthebaseofthebuildinginducedbynearbymovingroadvehiclesareassumedtobestationaryrandomprocesses.Atypicalthree-storymicroelectronicsbuildingisselectedasacasestudy.Thecasestudyshowsthattheverticalvibrationofthemicroelectronicsbuildingishigherthanthehorizontal.TheuseofahybridcontrolplatformcaneffectivelyreducebothhorizontalandverticalmicrovibrationsofthemicroelectronicsequipmenttothelevelwhichsatisfiesthestringentmicroscalevelocityrequirementspecifiedintheBoltBeranek&Newman(BBN)criteria.
简介:Thecenterlinesegregationincontinuouscastingsteelisknowntobeformedbytheinterdendriticenrichedliquidflowatthesolidificationendinstrand.Atpresent,severalmethods,suchasthermalsoftreduction,electromagneticstirringanddynamicsoftreduction,areavailabletoreducethecentersegregationandtoimprovetheinternalquality.Althoughsomemethodscouldalleviatecentersegregationtosomeextent,theycanalsogiverisetonewproblems.Forinstance,thermalsoftreductioncanleadtosurfacecrackingduringcastingofsomesteelsandelectromagneticstirringcanresultinwhiteband.Dynamicsoftreductionisaneffectivetechnologyfortheimprovementofstrandqualityincontinuousslabcasting.Inthispaper,thekeyparametersofdynamicsoftreductiontechnology,suchassoftreductionregion,thetotalreductionamount,forlowcarbonsteelhavebeenstudiedbasedonexperimentalandtheoreticalanalysis.Thesoftreductionregionwasrelatedtothesegregationofchemicalcomposition,slabbulgingofnarrowsideandavoidinginternalcrackofslab.Thetotalreductionamountwascomposedofnaturalthermalshrinkageandactualreductionamountdependingoncriticalstrain.Forlowcarbonsteelwithslabdimensionof(950-1950)mm×170mm,thesolidfractionrangeinsoftreductionregionwasrecommendedfrom0.4to0.8,thetotalreductionamountwas2.0-2.8mm,andtheoptimizedreductionratewas0.4-1.2mm/min,respectively.Furthermore,adynamicsoftreductionsystemincontinuousslabcasting,VisualCast-Dynamic,hasbeendevelopedbymultithreadingmethod.Itdemonstratedthatthedynamicsoftreductionmodelinthisstudywascorrectwiththeabilityofonlinecontrol.
简介:ThispaperdealswiththeoutputfeedbackH∞controlproblemforaclassofnonlinearstochasticsystems.Basedonthelatestdevelopedtheoryofstochasticdissipation,anotableresultaboutthenonlinearH∞outputfeedbackcontrolofdeterministicsystemisgeneralizedtothestochasticcase.Finally,inthecasesofstatefeedbackandoutputfeedback,twofamiliesofcontrollersareprovidedrespectively.
简介:Thispaperconsiderstheoptimaltrafficsignalsettingforanurbanarterialroad.Byintroducingtheconceptsofsynchronizationrateandnon-synchronizationdegree,amathematicalmodelisconstructedandanoptimizationproblemisposed.Then,anewiterativealgorithmisdevelopedtosolvethisoptimaltrafficcontrolsignalsettingproblem.Convergencepropertiesforthisiterativealgorithmareestablished.Finally,anumericalexampleissolvedtoillustratetheeffectivenessofthemethod.
简介:Recently,someresearchesindicatethatpositivefeedbackcanbenefitthecontrolifappropriatetimedelayisintentionallyintroducedintocontrolsystem.However,mostworkistheoreticalonebutfewareexperimental.Thispaperpresentstheoreticalandexperimentalstudiesofdelayedpositivefeedbackcontroltechniqueusingaflexiblebeamasresearchobject.Thepositivefeedbackweightingcoefficientisdesignedbyusingtheoptimalcontrolmethod.Theavailabletimedelayisdeterminedbyanalyzing...
简介:Thispaperdevelopesatemperaturecontrolsysteminordertocarryoutarealtimeandcontinuousobservationonlivingcellsunderthemicroscope.Inthissystem,transparentindiumtinoxid(ITO)conductivefilmwasusedasaheater,temperaturewasmeasuredbythetemperaturedependenceofresistancebehavioroftheITOfilm,C8051F340single-clupwasusedasthecontrolhardwarecore,andthemodifiedPIDalgorithmandpulsewidthmodulation(PWM)wereadoptedasthekeycontrolsoftwareprograms.Thetemperaturesystemhadasimplestructurewithoutaddedtemperaturesensor,anuniformtemperaturedistributionwithin±1℃ontheITOfilmsurfaceandtemperaturecontrolprecisionof±0.2℃couldbeobtained.ThesystemcouldmaintainagoodgrowthstateforBHK-21livingcellunderthemicroscopefor48h.
简介:ThisletterproposesaratecontrolalgorithmforH.264videoencoder,whichisbasedonblockactivityandbufferstate.ExperimentalresultsindicatethatithasanexcellentperformancebyprovidingmuchaccuratebitrateandbettercodingefficiencycomparedwithH.264.ThecomputationalcomplexityofthealgorithmisreducedbyadoptinganovelblockactivitydescriptionmethodusingtheSumofAbsoluteDifference(SAD)of16×16mode,anditsrobustnessisenhancedbyintroducingafeedbackcircuitatframelayer.
简介:Aspartofacomprehensiveenvironmentalmanagementsystem,manycountriesestablishemissioncontroltargetsformassemissionsofapollutant.Suchtargetsareoftenthekeyobjectiveofanenvironmentalpolicy,suchasanemissiontradingprogram.InChina,however,itismorethanjustanobjectiveofoneparticularpolicy;ithasbecomeaconceptthathasinfluencedmanynationalenvironmentalpoliciesandactivities.Theobjectiveofthisarticleistoreviewtheimplementationofthetotalemissioncontrolpolicyinthepast10yearsandexploreemergingissuesinitsimplementation.Thearticlehasthreesections:asummaryoftheimplementationexperience,issueswiththedesignandimplementationofthepolicy,andpolicyrecommendations.
简介:Anexperimentalinvestigationonairfoil(NACA64-215)shockcontrolisperformedbyplasmaaerodynamicactuationinasupersonictunnel(Ma=2).Theresultsofschlierenandpressuremeasurementshowthatwhenplasmaaerodynamicactuationisapplied,thepositionmovesforwardandtheintensityofshockattheheadoftheairfoilweakens.Withtheincreaseinactuatingvoltage,thetotalpressuremeasuredattheheadoftheairfoilincreases,whichmeansthattheshockintensitydecreasesandthecontrolefectincreases.Thebestactuationefectiscausedbyupwind-directionactuationwithamagneticfield,andthendownwind-directionactuationwithamagneticfield,whilethecontrolefectofaerodynamicactuationwithoutamagneticfieldisthemostinconspicuous.Themeanintensityofthenormalshockattheheadoftheairfoilisrelativelydecreasedby16.33%,andthenormalshockintensityisrelativelyreducedby27.5%when1000Vactuatingvoltageandupwind-directionactuationareappliedwithamagneticfield.ThispapertheoreticallyanalyzestheJouleheatingefectgeneratedbyDCdischargeandtheLorentzforceefectcausedbythemagneticfield.Thedischargecharacteristicsarecomparedforallkindsofactuationconditionstorevealthemechanismofshockcontrolbyplasmaaerodynamicactuation.
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简介:Thedesignandperformanceanalysisofnetworkedcontrolsystemswithrandomnetworkdelayintheforwardchannelisproposed,whicharedescribedinastate-spaceform.Anewcontrolschemeisusedtoovercometheeffectsofnetworktransmissiondelay,whichistermednetworkedpredictivecontrol(NPC).Furthermore,threedifferentwaystochoosecontrolinputarediscussedandtheperformancesareanalyzed,respectively.Bothreal-timesimulationsandpracticalexperimentsshowtheeffectivenessofthecontrolscheme.
简介:Adissipative-basedadaptiveneuralcontrolschemewasdevelopedforaclassofnonlinearuncertainsystemswithunknownnonlinearitiesthatmightnotbelinearlyparameterized.Themajoradvantageofthepresentworkwastorelaxtherequirementofmatchingcondition,I.e.,theunknownnonlinearitiesappearonthesameequationasthecontrolinputinastate-spacerepresentation,whichwasrequiredinmostoftheavailableneuralnetworkcontrollers.Bysynthesizingastate-feedbackneuralcontrollertonaketheclosed-loopsystemdissipativewithrespecttoaquadraticsupplyrate,thedevelopedcontrolschemeguaranteesthattheL2-gainofcontrolledsystemwaslessthanorequaltoaprescribedlevel.Andthen,itisshownthattheoutputtrackingerrorisuniformlyultimatebounded.Thedesignschemeisillustratedusinganumericalsimulation.