将软件模拟技术运用于供应链管理中外文翻译Word格式文档下载.docx
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VPInternationalOperations
SystemsModelingCorporation
Introduction:
Thispaperintendstodiscusstheuseofsimulationforthosecompaniescurrentlyintheprocessofevaluatingtheirsupplychaintogainperformanceimprovements(suchascustomerservice,costcutting,etc.)fortheiroperations.Thisdocumentdoesnotcoveringreatdetailfeaturesandapplicationsofthistechnology,ratheritfocusesonthebenefitsofusingsimulationasaneffectivetooltomanageandunderstandyoursupplychain.ThereissubstantialinformationavailablefromvendorsontheInternetonsupplychaintechnologysuchastheSupplyChainCouncilorforsimulationattheSocietyforComputerSimulation.
Somebasicsonthesetechnologiesfirst:
Simulation(discrete-event)canbedefinedas:
creatingacomputermodelofarealorproposedsystemandconductingexperimentsonthemodeltodescribeobservedbehaviorand/orpredictfuturebehaviorbeforeinvestinganytimeormoney.Becauseexperimentingonarealsystemcouldbecostlyand/orimpractical,simulationhasbecomeanextremelyimportanttoolfordesigningandanalyzingcomplexsystems;
itisacost-effectivewayoftestingproposedsystems,plans,orpoliciesbeforeincurringtheexpenseofprototypes,fieldtests,oractualimplementations.Infact,manymanagershavecometoviewsimulationasaninexpensiveinsurancepolicy.SimulationsometimesgetsconfusedwithBusinessProcessFlowcharting,WorkFlowModelingorProcessModeling.Inactuality,simulationhasoriginsinthefactoryfloor--mostfrequentlyusedintheautomotiveindustryforovertwentyyears.Morerecentlywithallthechangesinthebusinessworlddueto“downsizing”,“rightsizing”andmergers/acquisitions,manyfirmsrealizethebenefitsofusingsimulationbystudyingprocesses(likeafactory)toshowtheeffectofchangeontheircompany.Today’ssimulationsoftwaretoolsrequireend-userinputthroughtestingandevaluation(what-ifanalysis)togetafinal“optimizedsystem.”Intheend,though,simulationisacostsavingtool.Ithassavedcompaniesmillionsofdollarsbyofferinginsightformanagementdecision-makingoncomplexsystems;
abenefitthatisdifficulttomatchusingothertechnologiesormathematicalmethodologies.
SupplyChainManagementhasbeendefinedbylogisticsprofessionalsas:
(the)managingoftheflowofmaterialsandproductsfromthesourcetotheuser.ThefourbasicprocessesofPlan,Source,MakeandDeliveraremostusuallynotedinthisindustry.Soundssimplebutactuallyisquitecomplexduetotheinterdependenciesinasupplychain.Thisflowtypicallyincludesaspectsofpurchasing,manufacturing,capacityplanning,operationsmanagement,productionscheduling,manufacturingrequirementsplanning(MRPII),distributionsystemplanning,transportationsystems,warehousingandinventorysystems,anddemandinputfromsalesandmarketingactivities.Itcanbefromasingleproductlineorproductionplanttoacomplexchainthatincludesmultipledemandsources,suppliers,distributionmeansorfactories.supplychainsarebeing“managed”thesedaysbysoftwarecalledAdvancedPlanningandScheduling(APS)systems.CompaniesinthisindustryincludeI2Technologies,Manugistics,Numetrix,SASInstituteandmore.Thesetoolsoffertheabilitytorapidlyandsimultaneouslyplanandschedulecustomerdemandwhileconsideringmaterialsandcapacityconstraints.Theyprovidetheabilitytoincreaserevenues,improvecustomerserviceandcutcostsbysynchronizedmanagementofthecompletesupplychain.Thepotentialinimprovedbusinessperformanceisenormous.TheAPSmarketspaceisexploding,roughly$700mUSDin1998andexpectedtotripleinthenext2-3years.TheseAPSsystemsalsoappeartobeinfringingonthehugeEnterpriseResourcePlanning(ERP)marketasnotedbymanyoftheindustryjournalsthesedays.ERPisthetermusedtodescribeintegratedcomputersystemsforcorporatecomputing–sometimescalledthe“transactionalbackbone”ofacompany.ManyofthelargeERPsupplierssuchasSAP,Oracle,PeopleSoftandBaanhaveplanstointroducesupplychainmanagementfunctionalityintotheirsoftwareinthenearfuture.
Finally,dependingonthescopeoftheproblemsinthesupplychain,therearetypicalcoremethodologies–knownas“solvertechnologies”whichinclude;
heuristics,constraintmanagement,linearprogramming,mixed-integerprogrammingandnetworkprogrammingthatprovidetheresultsoroutputsoftheAPStools.Conversely,simulationitisnota“solvertechnology”ratheritisamethodologytoevaluatedetailedsolutionsandalternativesinthesupplychain.
Today’senterpriseenvironment:
Ifyoucouldsummarizeinafewphrasesthesedaysaboutbasicinternalorexternalenvironmentalconditionsthatmostcompany’sfacetoday,Iamsuremostwouldsaytheyareexperiencing:
∙constantlychangingoperations-(productionline,factory,warehouse,distributionsystems,pening/closing/expanding/contracting)
∙mergers,acquisitionsorjointventures
∙informationsystemschanging/merging
∙increasingcompetition
∙increasingcustomerexpectations
∙demandsforhigherprofits
∙complexsystemsintegration
∙conflictingmanagementobjectives-centralize,decentralize,etc.
∙automationandoutsourcingneeds
∙masscustomizationpressures
∙changinginventorypolicies
manymoreforsure….
Thepointisthatallbusinessesaredefinedbyconstantchangeandvariability.Ateverincreasingratesofspeed,fasterandfaster.
Then,whyuseSimulation?
Thosecompaniesthatdonotchangetoimprove–certainlyeventuallygooutofbusinessorlosemarketshareinsomeway.Simulationisthefriendofchangeandcancapturetherandomnessofsystems.Bythis,itismeantthatsimulationcanmodelthecorporatedynamicsinthecompletesupplychain,fromsourcetotheuserinthroughoutthePlan,Source,MakeandDeliverprocess.Howcansimulationcapturethevariability?
Thisismainlyduetothestatisticalnatureofsimulationtools.Theoutputisbothstatisticaldataandperformanceanimationtoviewthesystemdynamics.Simulationcanreliablycaptureandpredicttheeffectofmultiplechangesincorporatesystems.Ifsomebodysaid,“Icanofferyouaviewofhowyoursystemwillperform”mostsaneindividuals(withtheircareersinconsideration)willconsiderthesimulation.Sadly,though,oftensimulationisconsideredonlyaftersystemsareinstalledandworkingimproperlyordonotworkatall.Simulationisaninsurancepolicytopredictsystemperformancetoprovideoptimalresults.
Thekeytounderstandsupplychainperformanceistounderstandthevariabilityoftheprocessesinthesystem.Allthoseitemsmentionedaboveclearlyaffectsupplychainefficiency.Thosecompaniesthatcangaintheknowledgeofthesystemdynamicscanmakebetterevaluations(testdriveorperform“what-ifanalysis”)ofthesupplychaintoimprovetheperformance.Asimulationprojectforcestheunderstandinginastep-by-stepmethod,ofsystemoperationsandthusdefinesthesystemclearlyandthereforeminimizesmultiple(mis)interpretationsastothecomplexityandvariabilityoftheprocesses.Ifyoucanunderstandsupplychaindynamicsandvariabilitybehavior,betterperformancefromthesupplychaincanbeexpected(e.g.lowerinventories,bettercustomerservice.)
Asimulationprojectisinexpensiverelativetothecostofsupplychainsoftwareinstallationandmanagement.TheROIofaprojectiseasilyjustifiedinavoidedcoststhatwillbeevidentintheresultsoftheproject.
Whataresomeexamplesofsystemrandomnessandvariability?
Asnotedabove,thereismuchchangeinourbusinessenvironmenttoday.Therearemanyeverydayoccurrencesthatmakethedecisionmakingprocessdifficultduetothefastchanginginformationputbeforemanagement.Followingaresomeoftheproblemsneedingtoconsiderationforyoursupplychainmodel.
Manufacturing:
∙Stockoutsituations
∙Partsnotarrivingontimeforsubassemblyoperations
∙Machinesbreakinganddisruptingproduction
∙Laborproblems
∙Machinesetup/retoolings
∙Newproductlineintroductions
Warehousing/Distribution:
∙Automatedmaterialhandlingsystemsbroken
∙Trucking/Shipping/Air/Railsystemsdeliverlate
∙Spacingconstraints
InformationTechnology:
∙Changingbusinessprocessesduetomergers/acquisitions
∙Constantlychangingbusinesscomputersystems
MarketConditions:
∙Customerchangingdemand
∙Economicconditions
∙Currencyconditions
Whatspecificallycansimulationdotoimprovesupplychainperformance?
Therearemanyareastoconsiderusingsimulationinyoursupplychainmanagement.
Firstfromanaggregatepointofview,akeyquestionalwaystoconsiderinsupplychainmanagementis“Whatarethetrade-offstoachievehighcustomerservicelevelsvs.associatedcosts(andrelatedprofits)toprovidethisservice?
”Ahighlevelsimulationmodelconsistingofthemanyparametersinthevarioussupplychainlinkswithappropriatestatisticaldatawillprovidevaluableinsightintothisquestion.Youcan“testdrive”yourpoliciesofdistribution/transportationrules,manufacturingrates,inventorylevels,etc.toseetheeffectonthecompletesystem.
Second,typicallythekeycomponentsofthesupplychaininclude:
∙Forecasting–seekstopredictthelevelsofactivitythatwilleffectproductdemand.
∙AdvancedPlanning–setsproductionovertimehorizonsofmonthsoryearsusingconstraintmodelsthattreatbothmaterialsandcapacity.
∙DynamicScheduling–dealswithafewdaystoweeksofproduction,thentakesinformationfromtheERPorAPSsystemsthengenerate