简介:Thesystemdynamicsofturningprocessescanbedescribedbyadelaydiferentialequation.Howtoimprovethestabilityandsuppressthevibrationofcuttingisofaninterestingtopic.Inthispaper,amultipletime-delaycontrollerisdevelopedbasedondiscreteoptimalcontrolmethodfortheturningvibrationscontrol.Numericalsimulationsarecarriedouttoverifytheefciencyofthecontroller.Resultsindicatethedesignedcontrollercansuppressthecuttingvibrationefcientlyandimprovethestabilityofthecuttingprocesses.Theinfluenceofdesignedtime-delayandsamplingtimeonthecontrolperformanceisalsodiscussed.
简介:Inthispaper,dynamicsofthediscrete-timepredator-preysystemwithAlleeeffectareinvestigatedindetail.ConditionsoftheexistenceforflipbifurcationandHopfbifurcationarederivedbyusingthecentermanifoldtheoremandbifurcationtheory,andthenfurtherillustratedbynumericalsimulations.ChaosinthesenseofMarottoisprovedbybothanalyticalandnumericalmethods.Numericalsimulationsincludedbifurcationdiagrams,Lyapunovexponents,phaseportraits,fractaldimensionsdisplaynewandrichdynamicalbehavior.Morespecifically,apartfromstabledynamics,thispaperpresentsthefindingofchaosinthesenseofMarottotogetherwithahostofinterestingphenomenaconnectedtoit.TheanalyticresultsandnumericalsimulationsdemostratesthattheAlleeconstantplaysaveryimportantrolefordynamicalbehavior.ThedynamicalbehaviorcanmovefromcomplexinstablestatestostablestatesastheAlleeconstantincreases(withinalimitedvalue).Combiningtheexistingresultsinthecurrentliteraturewiththenewresultsreportedinthispaper,amorecompleteunderstandingofthediscrete-timepredator-preywithAlleeeffectisgiven.
简介:Inthispaper,theeffectofaddingdifferentconcentrationsofkineticinhibitorsontheinductiontimeofhydrogensulfidehydrateformationinareactorequippedwithautomaticadjustabletemperaturecontrollerisstudied.Anovelmethodnamely"suddencooling"isusedforperformingtherelevantmeasurements,inwhichtheinductiontimeofH2Shydrateinthepresence/absenceofPVPandL-tyrosinewithdifferentconcentrations(100,500,and1000ppm)isdetermined.Asaresult,PVPwiththeconcentrationof1000ppminaqueoussolutionisdetectedasamoresuitablematerialforincreasingtheinductiontimeofH2Shydrateformationamongtheinvestigatedkinetichydrateinhibitors.
简介:Inthispaperwestudytheone-dimensionalreflectedbackwardstochasticdifferentialequationswhicharedrivenbyBrownianmotionaswellasamutuallyindependentmartingaleappearinginadefaultablesetting.Usingapenalizationmethod,weprovetheexistenceanduniquenessofthesolutionstotheseequations.Asanapplication,weshowthatunderproperassumptionsthesolutionofthereflectedequationisthevalueoftherelatedmixedoptimalstopping-controlproblem.
简介:Inthispaper,anewsimulationapproachforsolvingthemixedtrainschedulingproblemonthehigh-speeddoubletrackraillineispresented.Basedonthediscrete-timemovementmodel,weproposecontrolstrategiesformixedtrainmovementwithdifferentspeedsonahigh-speeddouble-trackrailline,includingbrakingstrategy,priorityrule,travellingstrategy,anddepartingrule.Anewdetailedalgorithmisalsopresentedbasedontheproposedcontrolstrategiesformixedtrainmovement.Moreover,weanalyzethedynamicpropertiesofrailtrafficflowonahigh-speedrailline.Usingourproposedmethod,wecaneffectivelysimulatethemixedtrainscheduleonarailline.Thenumericalresultsdemonstratethatanappropriatedecreaseofthedepartureintervalcanenhancethecapacity,andasuitableincreaseofthedistancebetweentwoadjacentstationscanenhancetheaveragespeed.Meanwhile,thecapacityandtheaveragespeedwillbeincreasedbyappropriatelyenhancingtheratiooffastertrainnumbertoslowertrainnumberfrom1.
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.