工业工程英文文献及外文翻译

附录附录1：英文文献LineBalancingintheRealWorldAbstract:LineBalancing(LB)isaclassic,well-researchedOperationsResearch(OR)optimizationproblemofsignificantindustrialimportance.Itisoneofthoseproblemswheredomainexpertisedoesnothelpverymuch:whateverthenumberofyearsspentsolvingit,oneiseachtimefacinganintractableproblemwithanastronomicnumberofpossiblesolutionsandnorealguidanceonhowtosolveitinthebestway,unlessonepostulatesthattheoldwayisthebestway.Hereweexplainanapparentparadox:althoughmanyalgorithmshavebeenproposedinthepast,anddespitetheproblem’spracticalimportance,justonecommerciallyavailableLBsoftwarecurrentlyappearstobeavailableforapplicationinindustriessuchasautomotive.WespeculatethatthismaybeduetoamisalignmentbetweentheacademicLBproblemaddressedbyOR,andtheactualproblemfacedbytheindustry.Keyword:LineBalancing,Assemblylines,OptimizationLineBalancingintheRealWorldEmanuelFalkenauerOptimalDesignAv.Jeanne19Aboîte2,B-1050Brussels,Belgium+32(0)[e-mail]1IntroductionAssemblyLineBalancing,orsimplyLineBalancing(LB),istheproblemofassigningoperationstoworkstationsalonganassemblyline,insuchawaythattheassignmentbeoptimalinsomesense.EversinceHenryFord’sintroductionofassemblylines,LBhasbeenanoptimizationproblemofsignificantindustrialimportance:theefficiencydifferencebetweenanoptimalandasub-optimalassignmentcanyieldeconomies(orwaste)reachingmillionsofdollarsperyear.LBisaclassicOperationsResearch(OR)optimizationproblem,havingbeentackledbyORoverseveraldecades.Manyalgorithmshavebeenproposedfortheproblem.Yetdespitethepracticalimportanceoftheproblem,andtheOReffortsthathavebeenmadetotackleit,littlecommerciallyavailablesoftwareisavailabletohelpindustryinoptimizingtheirlines.Infact,accordingtoarecentsurveybyBeckerandScholl(2004),thereappeartobecurrentlyjusttwocommerciallyavailablepackagesfeaturingbothastateoftheartoptimizationalgorithmandauser-friendlyinterfacefordatamanagement.Furthermore,oneofthosepackagesappearstohandleonlythe“clean”formulationoftheproblem(SimpleAssemblyLineBalancingProblem,orSALBP),whichleavesonlyonepackageavailableforindustriessuchasautomotive.Thissituationappearstobeparadoxical,oratleastunexpected:giventhehugeeconomiesLBcangenerate,onewouldexpectseveralsoftwarepackagesvyingtograbapartofthoseeconomies.ItappearsthatthegapbetweentheavailableORresultsandtheirdisseminationinToday’sindustry,isprobablyduetoamisalignmentbetweentheacademicLBproblemaddressedbymostoftheORapproaches,andtheactualproblembeingfacedbytheindustry.LBisadifficultoptimizationproblemevenitssimplestformsareNP-hard–seeGarryandJohnson,1979),sotheapproachtakenbyORhastypicallybeentosimplifyit,inordertobringittoalevelofcomplexityamenabletoORtools.Whilethisisaperfectlyvalidapproachingeneral,intheparticularcaseofLBitledsomedefinitionsoftheproblemhatignoremanyaspectsofthereal-worldproblem.Unfortunately,manyoftheaspectsthathavebeenleftoutintheORapproachareinfactcrucialtoindustriessuchasautomotive,inthesensethatanysolutionignoring(violating)thoseaspectsbecomesunusableintheindustry.Inthesequel,wefirstbrieflyrecallclassicORdefinitionsofLB,andthenreviewhowtheactuallinebalancingproblemfacedbytheindustrydiffersfromthem,andwhyasolutiontotheclassicORproblemmaybeunusableinsomeindustries.2ORDefinitionsofLBTheclassicORdefinitionofthelinebalancingproblem,dubbedSALBP(SimpleAssemblyLineBalancingProblem)byBeckerandScholl(2004),goesasfollows.Givenasetoftasksofvariousdurations,asetofprecedenceconstraintsamongthetasks,andasetofworkstations,assigneachtasktoexactlyoneworkstationinsuchawaythatnoprecedenceconstraintisviolatedandtheassignmentisoptimal.Theoptimalitycriteriongivesrisetotwovariantsoftheproblem:eitheracycletimeisgiventhatcannotbeexceededbythesumofdurationsofalltasksassignedtoanyworkstationandthenumberofworkstationsistobeminimized,orthenumberofworkstationsisfixedandthelinecycletime,equaltothelargestsumofdurationsoftaskassignedtoaworkstation,istobeminimized.AlthoughtheSALBPonlytakesintoaccounttwoconstraints(theprecedenceconstraintsplusthecycletime,ortheprecedenceconstraintsplusthenumberofworkstations),itisbyfarthevariantoflinebalancingthathasbeenthemostresearched.WehavecontributedtothateffortinFalkenauerandDelchambre(1992),whereweproposedaGroupingGeneticAlgorithmapproachthatachievedsomeofthebestperformanceinthefield.TheGroupingGeneticAlgorithmtechniqueitselfwaspresentedindetailinFalkenauer(1998).Howeverwellresearched,theSALBPishardlyapplicableinindustry,aswewillseeshortly.ThefacthasnotescapedtheattentionoftheORresearches,andBeckerandScholl(2004)definemanyextensionstoSALBP,yieldingacommondenominationGALBP(GeneralizedAssemblyLineBalancingProblem).Eachoftheextensionsreportedintheirauthoritativesurveyaimstohandleanadditionaldifficultypresentinreal-worldlinebalancing.WehavetackledoneofthoseaspectsinFalkenauer(1997),alsobyapplyingtheGroupingGeneticAlgorithm.ThemajorproblemwithmostoftheapproachesreportedbyBeckerandScholl(2004)isthattheygeneralizethesimpleSALBPinjustoneortwodirections.Therealworldlinebalancing,asfacedinparticularbytheautomotiveindustry,require