BioWhat is Simulation?Types of SimulationSimulation Module GoalsSimulation Module OutlineOptional ReferencesThe Simulation ProcessSimulation GoalClearPictures: Simulation GoalsSystem ModelingSystem ModelingClearPictures Production ModelModel ImplementationValidation & DebuggingExperiment DesignClass 1 Wrap-Up2002 - Jérémie GallienSystems Optimization and Analysis(15.066J) Simulation ModuleProfessor Jérémie GallienOperations Management Group,MIT Sloan School of Management2002 - Jérémie GallienBio• Eng.D in Production Systems from Ecole des Mines de Paris, France• Ph.D in Operations Research from MIT• Research: Manufacturing Revenue Management, Dynamic Pricing, Auctions, Procurement, Scheduling…• Experience in eCommerce Fulfillment, Electronics, Aeronautics, Transportation and Software2002 - Jérémie GallienWhat is Simulation?• Application Domains: Science, Justice, Engineering, Education, Entertainment, Management…ExperimentInput A OutcomeSystemModelInput B OutcomeSystemModelInput B OutcomeRealSystemInput A OutcomeRealSystemModelingInferenceValidation2002 - Jérémie GallienTypes of Simulation• Physical Vs. Digital• Static Vs. Dynamic• Discrete Event Vs. Continuous TimeThis Module: Digital, Static & Dynamic Discrete Event Simulation2002 - Jérémie GallienSimulation Module Goals• Develop the practical skills necessary to design, implement and analyze discrete-event simulation systems;Practice of Modeling!!!• Cover the basic theory underlying discrete-event simulation methods.2002 - Jérémie GallienSimulation Module OutlineWeek Class Date Topic Reading Assignment11 15-Jul Introduction, Simulation Processand Stochastic Modeling2 16-Jul Monte-Carlo Theory andExamples (with Crystal Ball)TUT1 17-Jul Monte-Carlo Modeling andCrystal Ball Tutorial23 21-Jul Ontario Gateway CaseDiscussion4 22-Jul Discrete-Event Framework andExamples (with Simul8)TUT2 24-Jul Discrete-Event Modeling andSimul8 Tutorial35 28-Jul Discrete Event CaseDiscussion6 29-Jul Experimental Design andSimulation Analysis7 30-Jul Advanced Modeling Examples,Simulation-Based OptimizationTUT3 31-Jul Experimental Design andSimulation Analysis TutorialHomework 3Human Genome Case Write-UpProba/Stat Review 2 ChecklistHomework 2Homework 1Ontario Gateway Case Write-UpImplement ClearPictures model in Simul8Introduction to Simul8ClearPictures, Inc. Questions 1 to 3 in ClearPictures, Inc.Proba/Stat Review 1 Checklist2002 - Jérémie GallienOptional References• Law, A. and W. Kelton, Simulation Modeling and Analysis, 3rded., McGraw-Hill (2000).• Ross, S., Simulation, 3rded., Academic Press (2002).• Swain, J., “Power Tools for Visualization and Decision-Making,” OR/MS Today, February 2001. Available online at http://www.lionhrtpub.com/orms/surveys/Simulation/Simulation.html2002 - Jérémie GallienThe Simulation Process1 Define the simulation goal2 Model the system3 Implement the model4 Debug, Validate, Sensitivity5 Design the experiment6 Run the experiment7 Analyze and communicate• Keep the goal in mind!• Customer feedback!• Choice of tool is key• Never skip!• Customer feedback!• Never skip!• Use confidence intervals!• Run length, warm start, variance reduction…2002 - Jérémie GallienSimulation GoalSystem Design Vs. System AnalysisStrategic?Key PerformanceMeasures?Tactical?Control?• What about ClearPictures, Inc.?2002 - Jérémie GallienClearPictures: Simulation Goals• Estimate the average and standard dev. of delivery leadtime through the pull section;• Estimate the average and standard dev. of WIP inventory through the pull section;• Determine the production bottleneck;• Estimate the impact of purchasing more machines on leadtime and inventory;• …2002 - Jérémie GallienSystem Modeling• “Everything should be made as simple as possible, but not simpler.” Albert Einstein.• The simulation goal should be the guiding light when deciding what to model• Get client/user feedback early, and maintain model + assumption sheet for communication purposes• For random variables, collect data and fit distributions… after modeling the system, with sensitivity analysis in mind!2002 - Jérémie GallienSystem Modeling2a Model on paper2b User/Client feedback2c Sensitivity analysis• Process Flow Diagram, Flow Chart…• Model assumption sheet!• Theoretical: TOC, Queueing theory…2d Data collection & Fit• Prioritize, mock data example, fitting software1 Define simulation goal3 Implement the model4 Debug, Validate, Sensitivity2 Model the system5 Design the experiment2002 - Jérémie GallienClearPictures Production ModelBox / Sensor Board AssemblySensor Firmware TestST2ST1Inspection85%15%CustomerTRIAN[5,10,15]U[13,24]U[15,25]N[9.5,4]U[10,15]3602002 - Jérémie GallienModel Implementation• General programming language (C++, Java…)• Simulation-oriented language (MODSIM…)• Simulation software with GUI (Simul8®, Witness…)• Excel Add-in (Crystal Ball, @Risk…)FLEXIBILITY COST REQ. SKILLS DEV. TIME RUN TIMEGeneral Prog. Language Very High Low Very High High LowSimulation Language High High High Medium LowSimulation Software Medium High Medium Low MediumExcel Add-in Low Low Low Lowest High2002 - Jérémie GallienValidation & Debugging• Slow Graphical Animation• Step-by-step event list2002 - Jérémie GallienExperiment Design• Warm-up Period?• Run Length?• Number of Trials?• How to analyze and interpret the results?2002 - Jérémie GallienClass 1 Wrap-Up1. Simulation Process2. Modeling3. Choice of simulation