工业工程专业英语

Unit6NextGenerationFactoryLayouts,By谢文东、胡恒、陈小松、郑倩、凌丽,Thereisanemergingconsensusthatexistinglayoutconfigurationsdonotmeettheneedsofmultiproductenterprisesandthereisaneedforanewgenerationoffactorylayoutsthataremoreflexible,modular,andeasytoreconfigure.,现在存在新的共识，那就是现有的工厂布局构造并不能满足多产品企业的需求而且更灵活、更模块化的和较容易重构的新一代工厂布局是急需的。,Withincreasedflexibility,modularity,andreconfigurability,factoriescouldavoidredesigningtheirlayoutseachtimetheirproductionrequirementschanged.Creatingnewlayoutscanbeexpensiveanddisruptive,especiallywhenfactoriesmustshutdown.,因为有了更好的灵活性、模块化和可重构性，工厂每次在他们的产品要求改变的时候就避免了重新设计布局。特别当工厂必须关闭的时候，构造新的布局是昂贵的并对原有布局是具有破坏性的。,Becausefactoriesthatoperateinvolatileenvironmentsorintroducenewproductsregularlycannotaffordfrequentdisruptions,plantmanagersoftenprefertolivewiththeinefficienciesofexistinglayoutsratherthansufferthroughcostlyredesigns,whichmayquicklybecomesobsolete.,由于那些在易变环境中经营和经常引进产品的工厂不能承受频繁的破坏，工厂管理者一般宁愿忍受现有布局的低效也不会去花重金重新设计那些很快就会过时的布局。,Conventionallayouts,suchasproduct,process,andcellularlayouts,donotmeettheseneeds.Theyaretypicallydesignedforaspecificproductmixandproductionvolumethatisassumedtocontinueforasufficientlylongperiod(usually,threetofiveyears).,常规布局，比如产品、过程和一些由许多小单元组成的布局，不能满足这些需求。它们通常是为某一特定的产品结构和预计能持续足够长时间（通常为3到5年）的批量生产设计的。,Theevaluationcriterionusedinmostlayoutdesignprocedureslong-termmaterial-handlingefficiencyfailstocapturetheprioritiesoftheflexiblefactory(forexample,scopeismoreimportantthanscale,responsivenessismoreimportantthancost,andreconfigurabilityismoreimportantthanefficiency).,长期的物料装卸效率，一个曾经在绝大多数布局设计程序里使用的评价标准，没能占据灵活工厂的优先权（例如，机会比规模更重要，响应性比成本更重要，可重构性比效率更重要）。,Consequently,layoutperformancedeterioratesasproductvolumes,mix,orroutingsfluctuate.Astaticmeasureofmaterial-handlingefficiencyalsofailstocapturetheimpactoflayoutconfigurationonaspectsofoperationalperformance,suchaswork-in-processaccumulation,queuetimesatprocessingdepartments,andthroughputrates.,因此，工厂布局将随着产品体积、结构或者线路的波动而恶化。而且物料装卸效率的静态测量也没能在在制品的累积、处理部门的排队时间和生产率等使用性能方面影响工厂布局的重构。,Consequently,layoutsthatimprovematerialhandlingoftencauseinefficiencieselsewhereintheformoflongleadtimesorlargein-processinventories.,因此，那些能改善物料装卸的工厂布局总能在别处以长久的交货时间和大型制品存货的形式造成生产效率低下。,Whenproductvarietyishighorproductionvolumesaresmall,afunctionallayout,withallresourcesofthesametypeinonelocation,isoftenthoughttoprovidethegreatestflexible.,当产品种类多或者产量小的时候，一个在一处有同一类型的所有资源的功能性布局，通常被认为能提供更好的灵活性（见表一）。,However,afunctionallayoutisnotoriousforitsmaterial-handlinginefficiencyandschedulingcomplexity,whichcanleadtolongleadtimes,largework-in-processinventories,andinefficientmaterialhandling.,然而，它却因本身物料装卸效率低下和能造成更长的交货时间、大型制品存货和低效的物料装卸的调度复杂性而臭名昭著。,Whilegroupingresourcesbasedonfunctionprovidessomeeconomiesofscaleandsimplicityinallocatingworkloads,itmakesthelayoutsusceptibletomanufacturinginefficiencieswhentherearechangesinproductmixorroutings.Suchchangesoftenrequireacostlyredesignoftheplantlayoutorthematerial-handlingsystem.,尽管根据功能对资源分组能提供一些规模经济和简单的工作量分配，但它也使工厂布局在产品结构和路线出现变化的时候更易受生产效率低下的影响。这些变化往往需要对工厂布局或物料装卸系统做个昂贵的再设计。,Analternativetoafunctionallayoutisacellularconfiguration,inwhichthefactoryispartitionedintocells,eachdedicatedtoafamilyofproductswithsimilarprocessingrequirements.,替代功能性布局的是一个工厂能在其中被分为若干单元，而每一个单元又为有相似工序要求的产品系列专用的细胞结构。,Althoughcellularfactoriescansimplifyworkflowandreducematerialhandling,theyaregenerallydesignedtoproduceaspecificsetofproductswhosedemandlevelsareassumedtobestableandproductlifecyclessufficientlylong.,尽管细胞工厂能简化工作流程、减少物料装卸，他们也通常是用来生产理想中需求层次稳定、生命周期足够长的特定系列的产品。,Infact,cellsareusuallydedicatedtosingleproductfamilieswithlittleallowanceforintercellflows.Cellularfactoriesareinefficientwhendemandforexistingproductsfluctuatesornewproductsareintroducedoften.,事实上，细胞通常是致力于注液电池流程津贴少的单个产品系列。当现有产品需求波动时或新产品经常被引进，单元化工厂就很低效。,Someauthorshaveproposedalternativecellularstructurestoovercometheseproblems,suchasoverlappingcells,cellswithmachinesharing,andfractalcells.Althoughanimprovement,thesealternativesremainboundedbytheircellularstructure.,一些作者提出了可供选择的细胞结构去克服这些问题，如重叠单元、机器共享单元和分形体单元。虽然有了改善，但由于它们的细胞结构，这些替代物仍是有界的。,布局设计程序,无论是功能或细胞的布局,大部分已经都基于确定性的范例。这样的设计参数,如产品结构、产品的需求,产品线路被认为是确知的。,Layoutdesignprocedures，whetherforfunctionalorcellularlayouts，havebeenlargelybasedonadeterministicparadigm.Suchdesignparametersasproductmix,productdemands,andproductroutingsareassumedtobeknownwithcertainty.,设计标准往往是一个静态的效率来源(总共邻接得分效率,总成本,或者两者的结合),它不需要弹性和捕获可重构性。,Thedesigncriterionisoftenastaticmeasureofmaterial-handlingefficiency(atotaladjacencyscore,totalmaterial-handlingcost,oracombinationofboth),whichdoesnotcapturetheneedforflexibilityandreconfigurability.,事实上,人们对布局的灵活性和性能之间的关系知之甚少,评价分析模型亦不足。同时，影响对布局结构性能的弹性也不能很好的理解。当期设计标准不考虑影响布局效果的阻塞、周期时间、吞吐率等指标作为。,Infact,therelationshipbetweenlayoutflexibilityandlayoutperformanceispoorlyunderstoodandanalyticalmodelsforitsevaluationarelacking.Thestructuralpropertiesoflayoutsthataffecttheirflexibilityarealsonotwellunderstood.Currentdesigncriteriadonotcapturetheeffectoflayoutonsuchperformancemeasuresascongestion,cycletime,andthroughputrate.,他们也忽略了在工作场所中诸如设置、配料和装卸等操作参数的影响,更重要的是，他们仅仅测试平均水平,这种做法并不能保证所有的操作情况下的效率。很明显,我们需要一种新的布局,新的评价标准,新模型和方案程序。,Theyalsoignoretheimpactofsuchoperationalparametersassetup,batching,andloadingandunloadingatworkcenters.Moreimportant,theymeasureonlyaverageperformanceandinsodoingcannotguaranteeeffectivenessunderalloperatingscenarios.Clearly,weneedanewclassoflayouts,newevaluationcriteria,andnewmodelsandsolutionprocedures.,工业新兴的趋势工业上的几个重要新兴趋势能够改进布局设计问题甚至消除它。我们专注于五种趋势在商业实践,新技术、规划设计之间突出的互动,EmergingtrendsinindustrySeveralimportanttrendsareemerginginindustrythatcouldtransformthelayoutdesignproblemoreveneliminateit.Wefocusonfiveofthesetrendsofhighlighttheinteractionbetweennewbusinesspractices,newtechnologies,andlayoutdesign.,契约式制造在许多行业,外部供应商逐渐为原始设备制造商完成大部分的制造和装配(OEMS)。伴随着准时交货，外包已导致公司重组他们的最后组装设施以使供应商和原始设备制造商紧密耦合。,ContactmanufacturingInmanyindustries,outsidesuppliersareincreasinglydoingmostofthemanufacturingandassemblyfororiginalequipmentmanufacturers(OEMs).Alongwithjust-in-timedeliveries，outsourcinghasledtofirmsreconfiguringtheirfinalassemblyfacilitiestoaccommodateclosercouplingbetweensuppliersandOEMs.,例如,许多汽车制造商提供部件允许供货商直接用在他们的装配线。他们在工厂里设计了多重货物装卸和多个库存下滑分。,Forexample,manyautomobilemanufacturersallowsupplierstodelivercomponentsdirectlytopointsofuseontheirassemblylines.Theyhavedesignedmultipleloadingdocksandmultipleinventorydrop-offpointsthroughouttheirfactories.,为了支持模块化生产,在生产中依据产品的主要动脉或脊柱，设计师运用了脊柱的布局。联系到脊椎线是供应商拥有的袖珍型装配线,每个都是连接到自己模块中移动的产品。,Tosupportmodularplants,designersareusingspinelayouts,withtheproductmovingalongamainartery,orspinethroughtheplant.Linkedtothespinearemini-assemblylinesownedbythesuppliers,eachattachingitsownmoduletothemovingproduct.,混合布局糅合了流水线，多元、柔性制造的特点。这种布局形式使得工厂在不改变主体布局的情况下能够增加或减少供应商。它也能很大程度上调节供应商的生长和收缩。,Thehybridlayouthasfeaturesofaflowlineandmultiple,autonomouscells.Theconfigurationallowstheplanttoaddandremovesupplierswithoutchangingthemainlayout.Italsogracefullyaccommodatesthegrowthandcontractionofsupplieroperations.,工厂规划者需要选择不仅在个体,也能够在整体上使物料能够有效搬运的布局。作为一个工厂规划者，他所面对挑战是需要构建一个布局和物料搬运系统来保证核心的高效率和边缘的弹性和可重构性。,Facilityplannershadtochooselayoutsthatmakematerialhandlingefficientnotonlyineachindividualplantbutthroughoutthecomplex.Thechallengeforfacilityplannersisthentodevelopalayoutandamaterial-handlingsystemtopermithighefficiencyatthecoreandflexibilityandreconfigurabilityattheperiphery.,这个设计度量理应因生产区域的不同而异,但设计工具也应该支持在配备相同设备的状况下允许多种类型布局的存在。后来,我们稍后讨论的模块化布局即是为了应对在构建此类混合布局中所面临的挑战。,Thedesignmetricsshouldcertainlybedifferentdependingontheareaoftheplant,butthedesigntoolsshouldalsosupportavarietyoflayouttypeswithinthesamefacility.Themodularlayoutswediscusslateraddressinpartthechallengesofconstructingsuchhybridlayouts.,产品延迟差异化增加产品品种、大批量定制的需要使很多公司延迟产品差异化，延迟在制造过中产品带有个人特征的生产制造。,DelayedProductDifferentiationIncreasedproductvarietyandtheneedformasscustomizationhasledmanycompaniestodelayproductdifferentiation,postponingthepointinthemanufacturingprocesswhenproductsareassignedindividualfeatures.,例如，公司建立一个基于所有的产品的平台，但是直到一切实际需求为人所知,它才会赋与它特定产品的特征及零部件来区分它。,Companiesdothis,forexample,bybuildingaplatformcommontoallproductsanddifferentiatingitbyassigningtoitcertainproduct-specificfeaturesandcomponentsonlyafteractualdemandbecomesknown.,他们创建一个由类生产线组元组成的混合设备以建立公用平台以及类商店组元以他们定做产品。如果成品能够轻易的组合成家庭，那么这种车间结构就能够被单元代替，每一组元成为产品家庭的一份子。,Theycreatehybridfacilitiesconsistingofflow-line-likecomponentswheretheybuildthecommonplatformsandjobshop-likecomponentswheretheycustomizetheproducts.Iffinalproductsareeasilygroupedintofamilies,thejob-shopstructurecouldbereplacedbycells,eachdedicatedtooneoftheproductfamilies.,当走向了极端的时候由于设计布局问题延迟差异可以消除。例如，在越来越多的计算机的情况下如果需要定制在销售或分销仓库点的地方，工厂形成了单一的大批量，低种类的生产线。,Takentotheextreme,delayeddifferentiationcaneliminatetheproblemofdesigninglayoutsaltogether.Forexample,ifcustomizationtakesplaceatthepiontofsaleorindistributionwarehouses,asisincreasinglythecaseforcomputers,thefactorybecomesasinglehigh-volume,low-varietyproductionline.,惠普已经应用开展实施电脑和打印机分配中心的布局的战略，并在设立了海外的配送中心（例如，它的分配仓库安装特定国家的电源和电源线）。,Hewlett-Packardhasimplementedsuchastrategybycarryingoutthelocalizationstepsforitscomputersandprintersinitsoverseasdistributioncenters(forexample,itsdistributionwarehousesinstallcountry-specificpowersuppliesandpowercords).,仓储和制造的模糊的线路是一个值得令人关注的问题。如何从单纯的仓储设施改造仓库设施，也影响到他们做的轻型装配设计？应该如何改变，来适应仓库布局的既有效的存储和高效的制造和装配的需要？,Theblurringofthelinesbetweenwarehousingandmanufacturingraisesinterestingqestions.Howdoestransformingwarehousesfrompurestoragefacilitiestofacilitiesthatalsodolightassemblyaffecttheirdesign?Howshouldthelayoutofwarehouseschangetoaccommodateboththeneedsofefficientstorageandefficientmanufacturingandassembly?,在工厂内不同的步骤，显然对设计工具，支持混合布局，以及所有在同一屋檐下的功能的布局比较依赖。，我们接下来讨论的模块化的布局就趋于那个方向。,Inindustrieswherethedifferentiationstepsarecarriedoutinsidethefactory,thereisclearlyaneedfordesigntoolsthatsupporthybridlayoutsthatmayhavethefeaturesofproduct,cellular,andfunctionallayoutsallunderoneroof.Themodularlayoutswediscusslatercouldbeastepinthatdirection.,多通道制造对快速响应制造和低成品存货的要求增强，导致许多制造商和供应商额外投资到了附加的生产力上，通过运行并行生产线。,MultichannelManufacturingTheincreasedemphasisonquick-responsemanufacturingandminimumfinished-goodsinventoryhasledmanymanufacturersandsupplierstoinvestinadditionalcapacity,oftenbyrunningparallelproductionlines.,公司希望确保材料无缝流动，就通过拥有的灵活的生产线的产品共享。依赖下游的拥挤，产品可能搬进搬出邻进的生产线，创建多条路径，或通道，减少排队和拥挤。,Byhavingduplicateflexibleproducinglinessharedacrossproducts,companieshopetoensureaseamlessflowofmaterial.Dependingondownstreamcongestion,productscanmoveinandoutofneighboringproductionlines,creatingmultiplepaths,orchannels,minimizingqueueingandcongestion.,多渠道系统设计师面临着如何决定有许多重复的路径，以及如何组织工厂车间资源上重复这样的挑战。,Designersofmultichannelsystemsfacesuchchallengesasdetermininghowmanyduplicatepathstohaveandhowtoorganizetheresourceduplicatesontheplantfloor.,可扩展性的机器在过去的几年里，金属切削行业出现了，为了开发具有高度灵活性和可扩展性的可以执行许多功能并且可以调整各种能力的机器而共同努力的情况。,ScalableMachinesInthelastfewyears,therehasbeenaconcertedeffortinthemetalcuttingindustrytodevelopmachinesthatarehighlyflexibleandscalableandthatcanperformmanyfunctionsandbeadjustedforvariouscapacities.,机器可以很容易地通过插入额外的升级模块或获得额外的软件而提高功能和效率。如果成功，这种努力可能生产出使用的材料很少具有高的功效并且可以实现许多加工的机器,Thefunctionalityandefficiencyofthemachinescaneasilybeupgradedbyplugginginadditionalmodulesoracquiringadditionalsoftware.Ifsuccessful,sucheffortscouldleadtofacilitiesthatuseonemachineformostprocessingwithlittlematerialhandingandmovement.,因为一台机器可以快速设置为不同的组合和数量，生产需求的变化将会对布局的影响不大。这种可扩展的机器可以改变设计布局。,Becauseamachinecanberapidlyconfiguredfordifferentmixesandvolumes,changesinproductionrequirementswouldhavelittleeffectonlayout.Suchscalablemachinescouldtransformlayoutdesign.,如果物质运动变得微乎其微，工厂布局将大大简化他们的设计将是那么重要了。工厂设计的重点可能从各部门的详细设计转变许多部门的集合（例如，与装配或组装与检验相结合的加工和包装）。,Ifmaterialmovementbecameminimal,factorylayoutswouldbegreatlysimplifiedandtheirdesignwouldbelessimportant.Emphasisinfactorydesignwouldthenlikelyshiftformthedetaileddesignofeachprocessingdepartmenttothehigherlevelintegrationofthesedepartments(forexample,integratingmachiningwithassemblyorassemblywithinspectionandpackaging),便携式机器几家制造便携机器的制造商，他们很容易适应动态需求变化不同地区部署便携式工厂的机器就作为一种改变的要求。,PortableMachinesSeveralequipmentmanufacturersaremarketingportablemachinesthatareeasilyanddynamicallydeployedindifferentareasofthefactoryasrequirementschange.,便携式机器安装在工作场所和工件的-而不是其他方式（即工件固定和移动速度的机器发生）。因此，工厂就必须制定出促进机器的流动来代替机器的零件。,Theportablemachinesgototheworkplaceandmountontheworkpieces-insteadoftheotherwayaround(thatis,workpiecesarestationaryandmovementisincurredbythemachines).Hence,factorieswouldhavetobelaidouttofacilitatetheflowofmachinesinsteadofparts.,下一个产生的工厂布局三种方法来解决三个版面设计的柔性工厂独特需要。前两种新奇的布局配置，即分布式，模块化布局。,NextgenerationfactorylayoutsThreeapproachestolayoutdesignaddressthreedistinctneedsoftheflexiblefactory.Thefirsttwoapproachespresentnovellayoutconfigurations,namelydistributedandmodularlayouts.,在第三个方法，我们利用运算特性作为设计的标准来实现长期敏捷的布局,Inthethirdapproach,weuseoperationalperformanceasadesigncriteriontogeneratewhatwetermagilelayouts.,分布式布局分布式布局把包含很多职能的大部门分解为分布在车间的各处的子部门。重组部门分布于工厂的各处，这让设备能避免因未来工作流动模式和生产量波动而造成损失。,DistributedLayoutsDistributedLayoutsdisaggregatelargefunctionaldepartmentsintosubdepartmentsdistributedthroughouttheplantfloor(figure4).Duplicatedepartmentsstrategicallylocatedthroughoutthefactoryallowthefacilitytohedgeagainstfuturefluctuationsinjob-flowpatternsandvolumes.,相应的，分解和分布式的子部门能减少很多因产品因流动顺序而造成的物料运输距离。计划者可以很容易找到针对不同产品混合有效的流水线。,Inturn,disaggregatedanddistributedsubdepartmentsreducematerial-traveldistancesformanyproductionflowsequences.Plannerscaneasilyfindefficientflowsforawiderangeofproductmixesandvolumes.,这样的布局对波动很频繁的生产特别有效，它能让车间重组变得非常经济。这种情况下，一个固定的布局却能很好的满足很多情况下的生产。为了设计分布式的布局，公司会碰到很大的挑战。怎么设置子部门，一个类型的多少合适？,Suchlayoutsareespeciallyappealingwhendemandfluctuatestoofrequentlytomakereconfiguringtheplantcosteffective.Inthesesettings,afixedlayoutthatperformswellformanydemandscenariosisdesirable.Indesigningadistributedlayout,afirmfacesseveralchallenges.Howshoulditcreatesubdepartments,andhowmanyshouldithaveofeachtype?,给一个子部门分配多少容量合适？安置在哪里比较好？类似的子部门如何均衡工作负荷?部门如何分解和分配将怎么影响系统运作（例如，物料处理时间、半成品、排队时间）？,Howmuchcapacityshoulditassigntoeachsubdepartment?Whereshoulditplacethesubdepartments?Howshoulditlocateworkloadamongsimilarsubdepartments?Howwilldepartmentdisaggregationanddistributionaffectoperationalperformance(forexample,material-handlingtimes,workinprocess,andqueueingtimes)?,现在工艺路线越来越弹性化，公司将怎样控制物料的流动？如何调整各子部门类似物料加工的矛盾？,Howshouldthefirmmanagematerialflow,nowthatthereisgreaterroutingflexibility?howshoulditcoordinatethecompetingneedsformaterialhandlingofsimilarsubdepartments?,设计分布式的布局，公司应该采用怎样的工作指标？是满足多种生产要求下保证同预期物料处理成本一致，还是寻找各种生产情况下最低生产水平最为评价标准？,Whatperformancemeasureshouldthefirmusewhendesigningdistributedlayouts?Shoulditmeasureexpectedmaterial-handingcostoverpossibledemandscenarios,orshoulditseekameasureofrobustnessthatguaranteesaminimumlevelofperformanceforallscenarios?,更为重要的是，最终的生产布局对各种生产情况适应的敏捷性如何？虽然重组部门可能变得具有弹性了，但是它却也增加缩减了经济规模（例如，工人和一些辅助资源必须也一起重组）。,Moreimportant,howsensitivearethefinallayoutstotheadoptedperformanceforallscenarios?Althoughduplicatingdepartmentsmightincreaseflexibility,itcouldalsoincreaseanddiminisheconomiesofscale(forexample,operatorsandauxiliaryresourcesmustbeduplicated).,公司必须权衡分解部门所带来的物料加工益处，另一方面重组部门带来成本的增加。,Thefirmmusttradeoffthematerial-handingbenefitsofdisaggregationandduplicationagainstcostincreasesinotherareas.,模块化布局模块化布局不能描述成功能化、流水线或者单元性的，它是为适合复杂物料流动的系统的混合布局。,ModularLayoutsModularlayoutsarehybridlayoutsforsystemswithcomplexmaterialflowsthatcannotbedescribedasfunctional,flowline,orcellular.,制造业中一些新产生的趋势正引领这样的组合。比如汽车制造业在类似流水线中心的地方建立多种形式，与供应商提供的产品线紧密联系的模块布局，延迟产品差异化的公司也采用融合产品、流程、单元特征的布局方式。,Severaloftheemergingtrendsinindustryareleadingtosuchconfigurations.Forexample,theautomobileindustrybuildsmodularfactoriesaroundflow-line-likecoreswithconnectedsupplierproductionlinesinvariousforms.Firmsthatdelayproductdifferentiationalsouselayoutsthatcombineproduct,process,andcellularfeatures.,这样的模块化布局，制造商可以很快的调整他的生产规模。Irani和Huang关于模块化布局的研究（2000），试图回答下面几个最根本的问题。,Withsuchmodularlayouts,manufacturercanscaletheiractivityupanddownquickly.Intheirresearchonmodularlayouts,IraniandHuang(2000)soughttoanswerthefollowingfundamentalquestions.,有没有一个不同于传统的三种布局更能适合多种产品生产的物料流动。也许是三种传统布局的结合？,Couldalayoutotherthanthethreetraditionallayoutsbetterfitthematerialflowsofmultiproductmanufacturers?Perhapsacombinationofthethreetraditionallayouts?,通常情况下，一个模块布局的网络能否提供设计多产品生产设施的基本框架图？模块中成组、已分配好的资源能否与传统布局总运行距离和成本最低相一致？,Couldanetworkoflayoutmodulesprovideametastructurefordesigningmultiproductmanufacturingfacilitiesingeneral?Wouldgroupingandarrangingresourcesintomodulescorrespondingtospecifictraditionallayoutsminimizetotalflowdistanceorcosts?,敏捷布局对于需要满足设备频繁变动的布局可以考虑让使用特性最大化而不是物料装卸费最低。,AgileLayoutsInfacilitiesthatpermitfrequentreconfiguration,layoutscouldbedesignedtomaximizeoperationalperformanceratherthantominimizematerial-handlingcost.,因为产品生产策划时间越来越短，工厂纷纷从考虑长期运行成本经济转向短期响应力和敏捷性。像产品周期、半成品、库存、生产力这样的评估标准变得特别重要。,Asproduction-planningperiodsshrink,factoriesshifttheirfocusfromlong-runcostefficiencytoshorttermresponsivenessandagility.Suchperformancemeasuresascycletime,work-in-process(WIP)accumulation,andthroughputbecomeespeciallyimportant.,不幸的是，系统布局和运行特性间的关系并不那么好把握。Meller和Gau（1996）查阅了150篇关于工厂布局的文献，只找到了一个关于这个的文章。,Unfortunately,capturingtherelationshipbetweenlayoutconfigurationandoperationalperformanceisdifficult.MellerandGau(1996)reviewedover150papersonfactorylayoutandfoundonlyonethesubject.,最近，Benjaafar（2002）介绍了一个能找出布局和运行特性的分析模型。他把这个模型嵌入布局设计的程序里，这样，设计的规范也被纳入系统运行特性的评价指标之一。,RecentlyBenjaafar(2002)introducedananalyticalmodelcapableofcapturingtherelationshipbetweenlayoutconfigurationandoperationalperformance.Heembeddedthemodelinalayout-designprocedureinwhichthedesigncriterioncanbeoneofseveralmeasuresofoperationalperformance.,Heragu等人把Benjaafar的分析模型进行了扩展，他们补充了安装时间、转移、批量生产的规模，同时建立了一个能评估功能化、单元化的生产系统运行特性测量的方法。,Heraguetal.(2000)expandedBenjaafars(2002)modeltoincludeset-uptime,transfer,andprocessbatchsizeanddevelopedamethodthatcanestimateoperationalperformancemeasuresoffunctionalandcellularmanufacturingsystems.,研究挑战依然存在着研究的挑战性。在设计分布布局中，当前模型设计师假设，部门的数字复制和每件复制品容量都是知道的。实际上，设施设计师必须在开发布局之前做出这些决定。,ResearchchallengeSeveralresearchchallengesremain.Indesigningdistributedlayouts,designerso