Chapter-07-Slides

SimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide1of37IntermediateModelingandSteady-StateStatisticalAnalysisChapter7LastrevisionJune9,2003SimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide2of37WhatWe’llDo...•Model7-1:AsmallmanufacturingsystemEntity-dependentSequencesDatarequirementsandavailabilityVerification(debugging)•Statisticalanalysisofsteady-statesimulationsWarmupandrunlengthTruncatedreplicationsBatchingOthermethodsandgoalsSimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide3of37Model7-1:ASmallManufacturingSystem•Partarrivals,fourcells,partdepartures•Cells1,2,and4:singlemachineeach•Cell3:twomachines—newerone20%fasterNeed:waytomodelnon-identicalresourceunits•Circularlayoutofcells•Partsenteratleft,exitatright,travelonlyclockwise,alltransfertimes=2min.(realistic?)SimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide4of37ASmallManufacturingSystem(cont’d.)•ThreeseparateparttypesInterarrivals(alltypesmerged)~expo(13)minutes26%type1,48%type2,26%type3•Differentparttypesfollowdifferentroutes,havedifferent(triangular)processingtimes:•Observeutilizations,time/numberinqueues,cycletimes(timesinsystem)byparttype•Runfor32hoursParametersarefortheslowmachineatCell3.SimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide5of37NewArenaConcepts•Non-identicalmachinesatCell3•DifferententitytypesfollowdifferentprocessplansPreviousmodels–allentitieswentthroughsamesequenceofstations,maybewithDecidesforbranchingNow,needprocessplanwithautomaticroutingbyentitytype–differentSequenceassignedtoeachentity(likeanattribute),andentityfollowsitsownsequenceWon’tusedirectConnectorRoutes…insteadwetellentitiesdepartingfrommodulestofollowtheirownSequenceArenainternallykeepstrackofwhereentityis,whereitwillgonextSimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide6of37TheModelingApproach•Usuallytherearemanywaystobuilda(correct)ArenamodelAndalsomanywaystodosoincorrectly…•ImportanttothinkaboutdatastructuresWhatdataareavailable?Howwilltheybestoredinthemodel?•Forthismodel…UseSequenceforparttransfer(describedbelow)AspartofSequencedefinition,candefineAttributes–DoforprocessingtimesatallcellsbutCell1UseanExpressionforprocessingtimesatCell1UseVariablesfornew-machinespeedupatCell3,parttransfertimesSimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide7of37SequenceDataModule•AdvancedTransferpanel•Double-clickfornewrowforeachprocessplanNameforeachSequenceOpenStepscolumnforsubdialog–DefineorderedsequenceofStationstobevisitedintheSequence…musthaveStationNamesalreadydefined–Double-clicktoaddanewStationtothebottomoftheSequencelist;right-clicktoinsert/deletearow–Nameforeachstep–PossibleAssignmentsofAttribute,Variable,Pictures,etc.ateachstationintheSequence…thisisdonebeforetransferringtheentitytothisstepinthesequence–Inthismodel,AttributeassignmentusedtoattachProcessTimeAttributetoentityforthenextCell(exceptforCell1)SimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide8of37SequenceDataModule(cont’d.)•AssignSequenceNametoentitiesthatfollowit•InRoutemodules,selectSequenceasDestinationType(ratherthanStation)Departingentitylooksinitsownsequencetoknowwheretogonext•ArenatracksSequence-followingentitiesviaautomaticattributesSequencename,NS(orEntity.Sequence)Station(whereentityisorisgoingto),M(orEntity.Station)JobStepalongthesequence,IS(orEntity.JobStep)•Normally,entityisassignedaSequence,travelsitsroute,thenexitsCaninterruptthissequence,jumpforward/backward(tricky)•Remembertodefinethe“exit”stationSimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide9of37ExpressionDataModule•AdvancedProcesspanel•UseforprocessingtimesatCell1CouldhavedoneinSequences,asforotherCells…donethiswaymostlytoillustrateitsuse•ThreedifferentparttypesatCell1,souseavector-valuedExpressionwiththreerowsNamefortheexpression,Cell1TimesRows,3ExpressionValuessubdialog–Cell1processingtimesforthethreeparttypes–Ordermatters,sinceindexisparttype…willreferenceasCell1Times(PartIndex)inmodelSimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide10of37VariableDataModule•BasicProcesspanel•FactorvariableSpeedfactoratCell3–needatwo-rowvector–Assumenew(faster)machineis#1,old(slower)machineis#2–Setto0.8forindex1;setto1.0forindex2•TransferTimevariableHoldstransfer-timeconstantof2minutesbetweenstationsJustascalar,notavectorormatrixUsedformodelgenerality–ifalltransfertimeschanged,thismakesiteasytoimplementthischange•ThesearetheInitialValuesofvariables…anyentitycanchangethemButthey’reconstantinthismodelSimulationwithArena,3rded.Chapter7–IntermediateModeling&Steady-StateStat.AnalysisSlide11of37SetDataModule•BasicProcesspanel•DefinethreesetsResourceset,Cell3Machines–Fornewandoldmachine(inthatorder)atCell3–ResourceNames–couldhavealreadydefinedtheminResourcedat