Lecture 1 - Introduction to Simulation Edited.ppt

Lecture 1 - Introduction to Simulation Edited.ppt

1. Lecture 1
Chapter-01
Discrete-Event System Simulation
-Jerry Banks
Introduction to Simulation
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2. Introduction to Simulation
Simulation
the imitation of the operation of a real-world process or system over time
to develop a set of assumptions of mathematical, logical, and symbolic
relationship between the entities of interest, of the system.
to estimate the measures of performance of the system with the
simulation-generated data
Simulation modeling can be used
as an analysis tool for predicting the effect of changes to existing systems
as a design tool to predict the performance of new systems
Real-world
process
concerning the behavior of a system
A set of assumptions
Modeling
& Analysis
2

3. Miracle o
n the
Hudson in 2
009
with 155
passenger
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8. When Simulation is the Appropriate Tool (1)
Simulationenablesthestudyof,andexperimentationwith,the
internalinteractionsofacomplexsystem,orofasubsystem
withinacomplexsystem.
Informational,organizational,andenvironmentalchangescan
besimulated,andtheeffectofthesealterationsonthemodel’s
behaviorcanbeobserved.
Theknowledgegainedindesigningasimulationmodelmaybe
ofgreatvaluetowardsuggestingimprovementinthesystem
underinvestigation.
Bychangingsimulationinputsandobservingtheresulting
outputs,valuableinsightmaybeobtainedintowhichvariables
aremostimportantandhowvariablesinteract.
Simulationcanbeusedasapedagogicaldevicetoreinforce
analyticsolutionmethodologies.
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9. Simulationcanbeusedtoexperimentwithnewdesignsor
policiespriortoimplementation,soastoprepareforwhat
mayhappen.
Simulationcanbeusedtoverifyanalyticsolutions.
Bysimulatingdifferentcapabilitiesforamachine,
requirementscanbedetermined.
Simulationmodelsdesignedfortrainingallowlearning
withoutthecostanddisruptionofon-the-joblearning.
Animationshowsasysteminsimulatedoperationsothatthe
plancanbevisualized.
Themodernsystem(factory,waferfabricationplant,service
organization,etc.)issocomplexthattheinteractionscanbe
treatedonlythroughsimulation.
When Simulation is the Appropriate Tool (2)
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10. When Simulation is not Appropriate
Whentheproblemcanbesolvedusingcommonsense.
Whentheproblemcanbesolvedanalytically.
Whenitiseasiertoperformdirectexperiments.
Whenthesimulationcostsexceedthesavings.
Whentheresourcesortimearenotavailable.
Whensystembehavioristoocomplexorcan’tbedefined.
Whenthereisn’ttheabilitytoverifyandvalidatethemodel.
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11. Advantages and Disadvantages of Simulation (1)
Advantages
Newpolices,operatingprocedures,decisionrules,informationflows,
organizationalprocedures,andsooncanbeexploredwithoutdisrupting
ongoingoperationsoftherealsystem.
Newhardwaredesigns,physicallayouts,transportationsystems,andso
on,canbetestedwithoutcommittingresourcesfortheiracquisition.
Hypothesesabouthoworwhycertainphenomenaoccurcanbetested
forfeasibility.
Insightcanbeobtainedabouttheinteractionofvariables.
Insightcanbeobtainedabouttheimportanceofvariablestothe
performanceofthesystem.
Bottleneckanalysiscanbeperformedindicatingwherework-in-process,
information,materials,andsoonarebeingexcessivelydelayed.
Asimulationstudycanhelpinunderstandinghowthesystemoperates
ratherthanhowindividualsthinkthesystemoperates.
“What-if”questionscanbeanswered.Thisisparticularlyusefulinthe
designofnewsystem.
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12. Advantages and Disadvantages of Simulation (2)
Disadvantages
Modelbuildingrequiresspecialtraining.Itisanartthatislearned
overtimeandthroughexperience.Furthermore,iftwomodelsare
constructedbytwocompetentindividuals,theymayhavesimilarities,
butitishighlyunlikelythattheywillbethesame.
Simulationresultsmaybedifficulttointerpret.Sincemostsimulation
outputsareessentiallyrandomvariables(theyareusuallybasedon
randominputs),itmaybehardtodeterminewhetheranobservationis
aresultofsysteminterrelationshipsorrandomness.
Simulationmodelingandanalysiscanbetimeconsumingand
expensive.Skimpingonresourcesformodelingandanalysismay
resultinasimulationmodeloranalysisthatisnotsufficientforthe
task.
Simulationisusedinsomecaseswhenananalyticalsolutionis
possible,orevenpreferable.Thismightbeparticularlytrueinthe
simulationofsomewaitinglineswhereclosed-formqueueingmodels
areavailable.
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13. Areas of Application (1)
WSC(WinterSimulationConference):http://www.wintersim.org
ManufacturingApplications
Analysisofelectronicsassemblyoperations
Designandevaluationofaselectiveassemblystationforhigh-precision
scrollcompressorshells
Comparisonofdispatchingrulesforsemiconductormanufacturingusing
large-facilitymodels
Evaluationofclustertoolthroughputforthin-filmheadproduction
Determiningoptimallotsizeforasemiconductorback-endfactory
Optimizationofcycletimeandutilizationinsemiconductortest
manufacturing
Analysisofstorageandretrievalstrategiesinawarehouse
Investigationofdynamicsinaservice-orientedsupplychain
ModelforanArmychemicalmunitionsdisposalfacility
SemiconductorManufacturing
Comparisonofdispatchingrulesusinglarge-facilitymodels
Thecorruptinginfluenceofvariability
Anewlot-releaseruleforwaferfabs 13

14. Assessmentofpotentialgainsinproductivityduetoproactivereticle
management
Comparisonofa200-mmand300-mmX-raylithographycell
Capacityplanningwithtimeconstraintsbetweenoperations
300-mmlogisticsystemriskreduction
ConstructionEngineering
Constructionofadamembankment
Trenchlessrenewalofundergroundurbaninfrastructures
Activityschedulinginadynamic,multi-projectsetting
Investigationofthestructuralsteelerectionprocess
Special-purposetemplateforutilitytunnelconstruction
MilitaryApplication
ModelingleadershipeffectsandrecruittypeinanArmyrecruitingstation
Designandtestofanintelligentcontrollerforautonomousunderwater
vehicles
Modelingmilitaryrequirementsfornonwarfightingoperations
Multi-trajectoryperformanceforvaryingscenariosizes
UsingadaptiveagentinU.SAirForcepilotretention
Areas of Application (2)
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15. Logistics,Transportation,andDistributionApplications
Evaluatingthepotentialbenefitsofarail-trafficplanningalgorithm
Evaluatingstrategiestoimproverailroadperformance
Parametricmodelinginrail-capacityplanning
Analysisofpassengerflowsinanairportterminal
Proactiveflight-scheduleevaluation
Logisticsissuesinautonomousfoodproductionsystemsfor
extended-durationspaceexploration
Sizingindustrialrail-carfleets
Productdistributioninthenewspaperindustry
Designofatollplaza
Choosingbetweenrental-carlocations
Quick-responsereplenishment
Areas of Application (3)
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16. BusinessProcessSimulation
Impactofconnectionbankredesignonairportgateassignment
Productdevelopmentprogramplanning
Reconciliationofbusinessandsystemsmodeling
Personnelforecastingandstrategicworkforceplanning
HumanSystems
Modelinghumanperformanceincomplexsystems
Studyingthehumanelementinairtrafficcontrol
Areas of Application (4)
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