1. IET 525 System Analysis and Simulation Instructor: William J. Bender, Ph.D., PE, Office phone: 963-3543, Home # 509 933-3583 E-mail: benderw@cwu.edu please call or write Web Page www.cwu.edu/~benderw/benderw.html this page has syllabi, exams, and handouts Teaching Philosophy this is a graduate course students do a lot of reading and learning on our own. Class is for reviewing concepts, discussion, and group exercises. Labs are performed on students time “doesn’t have to be Wed night” Syllabi

2. Introduction Chapt 1 Need for Modeling & Simulation Terminology Model Building Simulation –Simulation Modeling & Analysis McGraw-Hill, by Law & Kelton –Discrete -Event Simulation Prentice Hall, by Banks, Carson, & Nelson Simulation of a Bank Teller Data Collection/ Statistics Apply what you know pg 17

3. Need for Modeling & Simulation Chemicals, Pharmaceuticals, hospitals, shipping, retail, defense, electronics, construction, manufacturing, shipping, communications …all industries need a method to “try something out” before building or changing a process/ manufacturing line. Bottom line helps decision makers solve complex problems by providing a systematic process to develop data, experiment and see what happens

4. Simulation “Building logical & mathematical models of real or proposed systems & use PCs to experiment with the parameters/ resources of the system. We will simulate systems via a simulation language called Visual SLAM…very user friendly AweSim is a program that runs the simulation & animates Visual SLAM … very user friendly one of many…I learned Extend a graphical simulation package that my dissertation was formed around

5. System We will perform “Systems Analysis” by modeling and simulation systems & see what happens A system is “Interdependent items that describe the area of interest or perform a specific function” And is defined by the SCOPE of the problem we are trying to solve Construction System Trades, Equip, Material, Processes, etc Design Weather Rules Suppliers

6. System External forces may effect system –Include –Ignored –Treated as inputs Construction System Trades, Equip, Material, Processes, etc Design Weather Rules Suppliers

7. Models Models are the description of systems/ abstract of the system –Physical ie WSU hydraulic lab –Math ie Differential equations, logical (CPM) –Graphical ie visual computer displays First models are built…then simulated to understand interactions of elements

8. Model Building Key is defining the elements of the model/ system & how they interact with each other –Problem statement or Goal –Established boundaries –Performance measures/ Design alternatives Takes an iterative process System Goal Boundaries Performance Model Simulate & Solve Problem

9. Simulation Build Models and experiment with it on a computer Benefits –Work out bugs before built if proposed ie hospital/ man line –W/O disturbing operating systems –NTD Model Design Parameters Performance Simulate Solve Problem

10. Simulation States Discrete or Continuous Continuous = constantly changing ie weather, waves, auto pilot Discrete Event = Small incremental steps ie construction, bank teller, manufacture line, etc –Deterministic ie 10 minutes or 2 days –Stochastic ie normally distributed, mean =10, std =2

11. Simulation of Bank Teller An example to show where we are going… Want to model the operations of a bank determine how long a person waits in line and % of time a teller is idle Model is: Wait for teller Customer Arrives Served by teller Exit bank How Long? % of time idle?

12. Simulation of Bank Teller Concepts At any instant model is in a particular state As events occur, state changes Events define the model Wait for teller Customer Arrives Served by teller Exit bank How Long? % of time idle?

13. Simulation of Bank Teller Pg 8& 9

14. Simulation of Bank Teller Event oriented Description To track customers in line & teller busy or idle at discrete points in time Time # in line Pg 10 & 11

15. Simulation of Bank Teller Event oriented Description Time Busy Need Data At any point in time the model is in a particular state Need “Book keeping” function to track changes Two perspectives 1)Customer 2)Teller Idle Teller Status

16. Data Collection & Analysis Use existing Data or Collect Data Existing data, ie census, cost data, government…may be easily obtained but typically very broad Surveys especially for qualitative material..Delphi Field Studies/ experimenting, expensive but best type Descriptive Statistics

17. Data Collection & Analysis Descriptive Statistics Grouping Data Group Data into cells for Frequency Distribution or Cumulative Frequency Displayed graphically as Histogram # of People Ave wait time

18. Data Collection & Analysis Descriptive Statistics Parameter Estimation Population = All possible observation Sample = only part of population Can estimate Population with mean =  and variance =  2 From a sample can find mean & variance to describe a population

19. Data Collection & Analysis Descriptive Statistics Distribution Estimation Use a know statistical distribution to estimate a population, ie normal, beta, exponential, weibel

20. Chapt 1 Summary Build Model based on goal, parameters, design, performance Simulate to experiment with model and solve problem Can use statistical estimation for data

21. Chapt 1 Exercises # 1-2 pg 18 Build a model for the MSET program from the students point of view similar to Figure 1-1 # 1-6 Describe/ draw the functional/mechanical operation of a car using boxes connected with arrows, use chassie, engine, transmission, wheels …by developing a model. How can this be simulated to understand the performance characteristics of Speed, MPG, cargo capacity, cost, performance ie 0-60mph time

22. Chapt 1 Exercises Solution # MSET program model similar to Figure 1-1 MSET Course Interest Project interest Advisor/ Committee Financial Rules/ degree requirements Available Classes Others?

23. Chapt 1 Exercises Solution # 1-6 Describe/ draw the functional/mechanical operation of a car using boxes connected by arrows, use chassie, engine, transmission, wheels …by developing a model. How can this be simulated to understand the performance characteristics of Speed, MPG, cargo capacity, cost, performance ie 0-60mph time ChassieengineTranyWheels Simulate by changing:weight, wheel base, engine size, engine turbo, engine gas/ diesel, trany gears, wheel size and out put performance of speed, MPH, HP, Size, Cost…others

24. Chapter 2 Simulation Modeling Perspectives Modeling World Views Discrete Simulations Continuous Simulations Visual SLAM

25. Simulation World Views The functional relationship of how a system is perceived and described Either: Discrete –Dependent variables change at specific points in simulated time Continuous –Dependent variables continuously change in simulated time

26. Discrete Discrete = Dependent variables change at specific points in simulated time –Construction of a road, Dependent Variable = % complete, specific lane openings –Window assembly line, Dependent Variable = people idle/busy, machine idle/busy –Bank Teller Dependent Variable = # of customers, teller idle busy Event Times Dependent Variable

27. Continuous Continuous = Dependent variables continuously change in simulated time –Sine wave approximation of an ocean wave Dependent variable is the height of the wave –Position of a space craft Dependent variable is exact location in orbit –Auto pilot of an aircraft, Dependent variables are speed, bearing, attitude, etc Time Dependent Variable

28. Combined Both discrete and continuous Some activity develops slowly over time and at a specific event the state changes Chemical process, slowly reaches a certain concentration then a catalyst is added an an explosion occurs Event Times Dependent Variable

29. Discrete Simulation Modeling Goal = Reproduce the activities the entities are engaged in to learn about the behavior of the system. –Entities = Objects within the boundaries of discrete system ie people, machines, $, resources –Activities = discrete function, unit of work –Event = Start or stop of an activity –Process = sequence of events that includes several activities

30. Discrete Simulation Modeling Discrete Sim formulated by 3 methods: Event Orientation = Define changes in the state at each event time (Busy/Idle) Activity Scanning Orientation = Describe the activities which entities engage in (system state based on activities condition) Process Interaction orientation = Describe process which activities flow (CPM)

31. Discrete Simulation Modeling Event Orientation Define changes in the state at each event time (Busy/Idle) Done by: Determine the events that can change the state of the system & use logic to model the system ie Bank System –Status of teller –# of customers Performed by maintaining a calendar of events and cause their execution simulated time

32. Discrete Simulation Modeling Activity Scanning Orientation Describe the activities which entities engage in (system state based on activities condition). Done by: describing activities & prescribe conditions which cause an activity to start or end Not used much (must scan all activities) except when an activity is indefinite or determined by a prescribed condition

33. Discrete Simulation Modeling Process Interaction Orientation Describe process which activities flow (CPM) Simulation that includes elements that occur in defined patterns Manufacturing/ construction/ where you want to understand the entire process

34. Discrete Simulation Modeling Process Interaction Orientation Model the flow of entities thru a system & define a sequence of events that are executed by the simulation

35. Continuous Simulation Modeling Dependent Variables change continuously over time Models are frequently written as derivatives….or differential equations SState variable S (wave height/ speed) over time T want to determine the response of the variable over time Or integrate ds/dt over time using numerical integration methods using simulation

36. Visual SLAM AweSim Visual SLAM is the computer language that is specifically written for simulation AweSim is the software product that combines language with modern window, graphics…makes SLAM user friendly Visual SLAM able to do discrete simulations as event or process orientations or both. Also does continuous and combined continuous/discrete.

37. Visual SLAM AweSim Consists of nodes and branches to model queues, servers, machines and decision points. DE modeler defines the events and the changes to the system when events occur Continuous model is represented by diff eq that describe the dynamic behavior of of the state variables

38. Modeling Perspectives Summary Discrete Simulations...three orientation mostly use –Event –Process Continuous Simulations –Defined by diff eq for constant changes Visual SLAM/ AweSim –Computer Language that performs simulation Will become clearer when we work with a simulation

39. Modeling Perspectives Exercises Page 32 # 2-3 Paint shop describe system using event orientation and process orientation #2-4 Describe HVAC control in terms of state variables, time events and state events

40. Modeling Perspectives Exercises Solutions # 2-3 Paint shop –event orientation 4 events, 1) arrive to prep area, 2) complete prep, 3) arrive at spray machine, 4) end spray/take out –process orientation essentially visualize an entity going thru the following sequence waiting for prep, prep, travel to spray, wait for spray, spraying #2-4 Describe HVAC control –state variable = temperature –time events = reset thermostat, turn on heat or cool, breakdown, lose power –state events temperature crosses the thermostatic setting….moisture content to turn on/off humidifier