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Chapt 3 Modeling

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Time studies, accessing data bases, statistical. Define Experimental Controls ... mtls,equip, machines, etc want to max their utilization=time productive ... – PowerPoint PPT presentation

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Title: Chapt 3 Modeling


1
Chapt 3 Modeling Simulation Processes
  • Intro/ steps in the process
  • Formulate problem
  • Specify the model
  • Build model
  • Simulate model
  • Use model
  • Support decision making
  • AweSim Visual Slam

2
Modeling Simulation Processes
  • Use an iterative process where relationships
    parameters are continually redefined improved.

3
Formulate the Problem
  • Focuses the modeling/ simulation efforts
  • 1) Identify the Goal
  • 2) Specify the system performance measures
  • 3) Set objectives
  • 4)Completely define the systems to be modeled

4
Formulate the Problem
  • Goals
  • specify what is to be achieved ie lower cycle
    time by capital investing
  • Performance measures
  • Measurable outputs ie profits/costs, inventory
    levels, speed, waiting time
  • Objectives
  • More specific, ie reduce queue/bottle neck for
    process or provide redundant machine for
    maintenance/ redundancy
  • Complete definition
  • Scope and boundary definitions

5
Specify Model
  • Define system but w/o unnecessary detail
  • Easily understood but realistic
  • Reasonable simplifying assumptions
  • Include interactions of activities
  • Conceptualize data requirements
  • collected
  • use statistical methods

6
Build Model
  • Develop Simulation model
  • Interactive Iterative- continually redefined,
    updated, modified extended
  • Collect data
  • Time studies, accessing data bases, statistical
  • Define Experimental Controls
  • Number of sim runs, report types/ plots/
    histograms, status of specific variables ie
    idle/busy
  • All steps are interdependent

7
Simulate Model
  • Run Model
  • Simulation advances time in accordance with the
    movement of entities thru nodes and activities
  • Verify Model
  • Does the model behave as expected ie correct CPM
    Does the model work right?
  • Validate the Model
  • Reasonable representation of the system, does the
    model truly represent reality?
  • Steps are interdependent/ have interactions

8
Use Model
  • Make the sim runs and interpretation of the data
    outputs
  • Make make several runs to find optimal solution
  • ie try run with one manufacturing set up - find
    output, tweak manufacturing set up - find out
    put, continue to tweak
  • Evaluate alternativesone bottle neck solved look
    for others that may crop up
  • Interactions.may need to rebuild model once see
    output

9
Support Decision Making
  • Presentation and documentation of the results/
    outputs of the simulations
  • Graphical is best

10
AweSim Visual SLAM
  • Open architecture to databases, MS office, C/C,
    Windows based
  • Project Structure builds scenarios to investigate
    alternate designs to improve a system
  • Build networks (models), perform simulations
    runs, view animations

11
AweSim Visual SLAM
12
AweSim Visual SLAM
13
Modeling Simulation Process Exercises
  • 3-2 Discuss the use of statistics and graphics
    in each of the steps of a modeling/ sim process
  • see fig 3-1 pg 36
  • 3-4 Using the steps in the modeling/ sim process
    build an explanatory model of the university
    system to obtain an MSET
  • see fig 3-1 pg 36

14
Chapt 4 Application of Simulation
  • Intro/ steps in the process
  • Performance measures
  • Examples
  • Capital Expenditures in the steel industry
  • Risk analysis of Pipeline const
  • MOB using Extend

15
Application of Simulation Introduction
  • Widely used by industrial engineering,
    management, by service industry, industrial
    products and government.
  • Manufacturing-plant layout, efficiencies, lean
    production
  • Project Controls-cost estimation, risk analysis,
    planning
  • Health care, transportation, communications,
    space flight, etc
  • Provided examples are only one solution
    typically many and may take several iterations

16
Performance Measures
  • Performance of a systems is measured by the
    efficiency is achieving its objectives
  • Objectives vary dependent on type of system
    involved ie car production vs plant construction
    general info provided by looking a manufacturing
    system

17
Performance Measures for Manufacturing Terms
  • System performance is combined with cost to
    establish profitability.Sim focuses on
    performance
  • Throughput production rate output/time
  • Capacitymax throughput
  • Flow time amount of time a job spends in the
    systemwant to min this
  • Resourcespeople, mtls,equip, machines, etc want
    to max their utilizationtime productive

18
Performance Measures for Manufacturing Terms
  • WIP Work In Progressunfinished units awaiting
    parts, mtl etc want to min this

19
Capital Expenditure in the Steel Industry
  • Improve ops involving melting scarp desulfuring
    metal by determining of submarines that cost
    1M

20
Capital Expenditure in the Steel Industry
  • Model scheduling rules, add rule to dump hot
    metal if submarine is not available to
    accommodate blast furnace..sim save buying
    another sub

21
Risk Analysis of Pipeline const
  • Problem formulation complete project by specific
    due dates
  • Sim construction activities based on weather and
    inputs to resources (people, equip, etc)

22
Use of Models
  • Modeling Sim used to enhance system performance
    or solve problems, Also for
  • Explanatory to understand a problem
  • Communication to describe
  • Training
  • Analysis
  • Review design alts

23
Application of Simulation Exercises
  • Using a block wiring diagram, develop a model for
    repairing/replace a building foundation
  • Want most efficient use of recourses
  • Activities are
  • lift up on jacks/ supports
  • remove existing foundation
  • Form/ pour new concrete foundation
  • Remove form/ lower building
  • Write what variables to Sim to create most
    efficient system

24
Application of Simulation MOB
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