简介:Inthispaper,wepresentanovelSupportVectorMachineactivelearningalgorithmforeffective3Dmodelretrievalusingtheconceptofrelevancefeedback.Theproposedmethodlearnsfromthemostinformativeobjectswhicharemarkedbytheuser,andthencreatesaboundaryseparatingtherelevantmodelsfromirrelevantones.Whatitneedsisonlyasmallnumberof3Dmodelslabelledbytheuser.Itcangrasptheuser'ssemanticknowledgerapidlyandaccurately.Experimentalresultsshowedthattheproposedalgorithmsignificantlyimprovestheretrievaleffectiveness.Comparedwithfourstate-of-the-artqueryrefinementschemesfor3Dmodelretrieval,itprovidessuperiorretrievalperformanceafternomorethantworoundsofrelevance
简介:Thispaperstudiesonlineschedulingofjobswithkindreleasetimesonasinglemachine.Here“kindreleasetime”meansthatinonlinesetting,nojobscanbereleasedwhenthemachineisbusy.EachjobJhasakindreleasetimer(J)≥0,aprocessingtimep(J)>0andadeadlined(J)>0.Thegoalistodetermineaschedulewhichmaximizestotalprocessingtime(∑p(J)E(J))ortotalnumber(∑E(J))oftheacceptedjobs.Forthefirstobjectivefunction∑p(J)E(J),wefirstpresentalowerbound√2,andthenprovideanonlinealgorithmLEJwithacompetitiveratioof3.Thisisthefirstdeterministicalgorithmfortheproblemwithaconstantcompetitiveratio.Whenp(J)∈{1,k},k>1isarealnumber,wefirstpresentalowerboundminf(1+k)/k,2k/(1+k)g,andthenweshowthatLEJhasacompetitiveratioof1+┌k┐=k.Inparticular,whenalltheklengthjobshavetightdeadlines,wefirstpresentalowerboundmax{4=(2+k),1}(for∑p(J)E(J))and4/3(for∑E(J)).ThenweprovethatLEJis┌k┐/k-competitivefor∑p(J)E(J)andweprovideanonlinealgorithmHwithacompetitiveratioof2┌k┐/(┌k┐+1)forthesecondobjectivefunction∑E(J).
简介:Sandblastingmachinesarewidelyusedinchemical,mechanicalandotherengineeringfields.Theinternalflowfieldofthesandblastingmachinebelongstoacomplexgas-solidtwo-phaseflow,andimpactbythecontinuousabrasivesandcancausethemachinetowearorevenfail.Inthisstudy,theEDEM-FLUENTcouplingmethodwasusedtocalculatethetransientflowfieldofthegasphaseandthemotion,dynamicandcollisioncharacteristicsofthesand.Airinthesandblastingmachinewastreatedastheidealgasandthecontinuousphase.Thesandwasregardedasthediscretephasesolidinthecomputation.UsingtheArchardwearmodel,thewearamountofthesandblastingmachinewascalculatedandthewearlawwasanalysed,toprovideatheoreticalbasisforoptimisingthedesignandoperationmethodoftheblastingmachine.
简介:Ininjectionmouldingproduction,thetuningoftheprocessparametersisachallengingjob,whichreliesheavilyontheexperienceofskilledoperators.Inthispaper,takingintoconsiderationoperatorassessmentduringmouldingtrials,anovelintelligentmodelforautomatedtuningofprocessparametersisproposed.Thisconsistsofcasebasedreasoning(CBR),empiricalmodel(EM),andfuzzylogic(FL)methods.CBRandEMareusedtoimitaterecallandintuitivethoughtsofskilledoperators,respectively,whileFLisadoptedtosimulatetheskilledoperatoroptimizationthoughts.First,CBRisusedtosetuptheinitialprocessparameters.IfCBRfails,EMisemployedtocalculatetheinitialparameters.Next,amouldingtrialisperformedusingtheinitialparameters.ThenFLisadoptedtooptimizetheseparametersandcorrectdefectsrepeatedlyuntilthemouldedpartisfoundtobesatisfactory.Basedontheabovemethodologies,intelligentsoftwarewasdevelopedandembeddedinthecontrollerofaninjectionmouldingmachine.Experimentalresultsshowthattheintelligentsoftwarecanbeeffectivelyusedinpracticalproduction,anditgreatlyreducesthedependenceontheexperienceoftheoperators.
简介:Sandblastingmachinesarewidelyusedinchemical,mechanicalandotherengineeringfields.Theinternalflowfieldofthesandblastingmachinebelongstoacomplexgas-solidtwo-phaseflow,andimpactbythecontinuousabrasivesandcancausethemachinetowearorevenfail.Inthisstudy,theEDEM-FLUENTcouplingmethodwasusedtocalculatethetransientflowfieldofthegasphaseandthemotion,dynamicandcollisioncharacteristicsofthesand.Airinthesandblastingmachinewastreatedastheidealgasandthecontinuousphase.Thesandwasregardedasthediscretephasesolidinthecomputation.UsingtheArchardwearmodel,thewearamountofthesandblastingmachinewascalculatedandthewearlawwasanalysed,toprovideatheoreticalbasisforoptimisingthedesignandoperationmethodoftheblastingmachine.
简介:Differentfrombirdsandinsects,batshavecomplexwing-deformationcapacitytogeneratehighaerodynamicforces.Inflight,theactivelymorphingofbatwingincludesthetwistingfromwingroottowingtip,thecamberingalongthechordwisedirection,thebendingalongthespanwisedirectionandthewingarea-changingcausedbythestretchandretractionofthewingspan.Itwasfoundthatthehighthrustandliftrequiredinbatflightaredependentonthewingtwistingandcamberingrespectively.Moreover,theintegratedwing-morphinggeneratestheaerodynamicliftandthrustmainlyduringthedownstrokeandalmostnegligibleforcesduringtheupstroke.Thewingarea-changingandbendingcanbeusedtoamplifythepositiveforcesinthedownstrokedurationandreducethenegativeforcesintheupstrokeduration.
简介:Thispaperusesthegeometricsingularperturbationtheorytoinvestigatedynamicalbehaviorsandsingularitiesinafundamentalpowersystempresentedinasingle-machineinfinite-busformulation.ThepowersystemcanbeapproximatedbytwosimplifiedsystemsSandF,whichcorrespondrespectivelytoslowandfastsubsystems.Thesingularities,includingHopfbifurcation(HB),saddle-nodebifurcation(SNB)andsingularityinducedbifurcation(SIB),arecharacterized.WeshowthatSNBoccursatPTc=3.4382,SIBatPTO=2.8653andHBatPTh=2.802forthesingularperturbationsystem.ItmeansthatthepowersystemwillcollapsenearSIBwhichprecedesSNBandthatthepowersystemwilloscillatenearHBwhichprecedesSIB.Inotherwords,thepowersystemwillloseitsstabilitybymeansofoscillationneartheHBwhichprecedesSIBandSNBasPTisincreasingtoacriticalvalue.Theboundaryofthestabilityregionofthesystemcanbedescribedapproximatelybyacombinationofboundariesofthestabilityregionsofthefastsubsystemandslowsubsystem.
简介:Thisworkdealswiththecoolingofhigh-speedelectricmachines,suchasmotorsandgenerators,throughanairgap.Itconsistsofnumericalandexperimentalmodelingofgasflowandheattransferinanannularchannel.Velocityandtemperatureprofilesaremodeledintheairgapofahigh-speedtestmachine.Frictionandheattransfercoefficientsarepresentedinalargevelocityrange.Thegoalsarereachedacceptablyusingnumericalandexperimentalresearch.Thevelocityfieldbythenumericalmethoddoesnotmatchineveryrespecttheestimatedflowmode.TheabsenceofsecondaryTaylorvorticesisevidentwhenusingtimeaveragednumericalsimulation.
简介:LECR4isthefirstECRionsourceusingevaporativecoolingtechnologyintheworld.Itsuniquefeatureisthatthesolenoidsweremadefromsolidsquarecopperwires(3.32mm×5.77mmwithinsulation),andthatallthecoilsareentirelyimmersedintheroomtemperaturecoolant.Thecoilscanproduceamaximumaxialmagneticfieldupto2.5T.LECR4aimstoprovideintensemultiplechargestateionbeamsforSSC-Linacproject-anewLinearinjectorfortheSeparatedSectorCyclotron(SSC).Presently,someionbeamswithdifferentM/QratiohavebeenacceleratedsuccessfullywiththeRFQandDTL,suchas200eμAof16O^5+,200eμAof40Ar^8+,50eμAof209Bi^30+etc.ThemeasuredtransmissionefficiencyofRFQisupto90%.ThelayoutofLECR4ionsourceandtheLEBTisshowninFig.1.
简介:Thispaperpresentsanapplicationofiterativelearningcontrol(ILC)techniquetothevoltagecontrolofsolidoxidefuelcell(SOFC)stack.Tomeetthedemandsofthecontrolsystemdesign,anautoregressivemodelwithexogenousinput(ARX)isestablished.Firstly,byregulatingthevariationofthehydrogenflowrateproportionaltothatofthecurrent,thefuelutilizationoftheSOFCiskeptwithinitsadmissiblerange.Then,basedontheARXmodel,threekindsofILCcontrollers,i.e.P-,PI-andPD-typearedesignedtokeepthevoltageatadesiredlevel.SimulationresultsdemonstratethepotentialoftheARXmodelappliedtothecontroloftheSOFC,andprovetheexcellenceoftheILCcontrollersforthevoltagecontroloftheSOFC.