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Computer Modeling and Simulation Simulation Software ICS41

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					        Simulation Software




ICS41: Computer Modeling and Simulation   Lecture#6:   1
Table of Contents
•   Comparison of Simulation Packages vs. PL
•   Classification of Simulation Software
•   Desirable Software Features
•   General-Purpose Simulation Packages
•   Object-Oriented Simulation Packages
•   Examples of Application-Oriented
        Simulation Packages




    ICS41: Computer Modeling and Simulation   Lecture#6:   2
Simulation Packages vs. PL

• Advantages (simulation packages vs. PL):
   – automatically provides most of the features
     needed to build simulation models
   – provide natural framework
   – generally easier to modify and maintain
   – provide better error detection




 ICS41: Computer Modeling and Simulation   Lecture#6:   3
Simulation Packages vs. PL

• Advantages (simulation packages written in PL):
   – most modelers already know a programming
     language
   – simulation model efficiently written in C or
     C++ may require less execution time
   – allow greater programming flexibility
   – software cost is lower



 ICS41: Computer Modeling and Simulation   Lecture#6:   4
Classification of Simulation Software
(aspects of simulation packages)
• General-Purpose vs. Application-Oriented
  Simulation Package:
        • Simulation Languages
        • Application-oriented Simulators




 ICS41: Computer Modeling and Simulation    Lecture#6:   5
Simulation Languages

• general in nature and model
  development was done by writing code.
• provide a great deal of modeling
  flexibility but difficult to use.




 ICS41: Computer Modeling and Simulation   Lecture#6:   6
Simulators

• oriented toward a particular application
  and a model was developed by using
  graphics, dialog boxes, and pull-down
  menus.
• easier to learn and use, but might not
  be flexible enough for some problems.




 ICS41: Computer Modeling and Simulation   Lecture#6:   7
Enhancements:

• Simulation languages:
   – attempt to employ graphical model-building
     approach.
• Simulators:
   – make their software more flexible by
     allowing programming in certain model
     locations using an internal pseudo-language.
        • it is now possible to modify existing modeling
          constructs and to create new ones.


 ICS41: Computer Modeling and Simulation       Lecture#6:   8
Therefore:

• general-purpose simulation package
   – can be used for any application, but might
     have special features for certain ones
• application-oriented simulation package
   – is designed to be used for a certain class of
     applications such as manufacturing, health
     care, and call centers.




 ICS41: Computer Modeling and Simulation   Lecture#6:   9
Classification of Simulation Software
(aspects of simulation packages)
• Modeling Approaches:
        • Event-scheduling Approach
        • Process Approach




 ICS41: Computer Modeling and Simulation   Lecture#6: 10
Event-scheduling Approach

• a system is modeled by identifying its
  characteristic events and writing a set of
  event routines that give detailed
  description of states.
• the simulation evolves over time by
  executing the events in increasing order




 ICS41: Computer Modeling and Simulation   Lecture#6: 11
Process Approach

• process
        • a time-ordered sequence of interrelated events
          separated by interval of time
• describes the entire experience of an
  “entity” as it flows through a “system”.




 ICS41: Computer Modeling and Simulation      Lecture#6: 12
  Process Approach




Process describing the flow of entity through a system

    ICS41: Computer Modeling and Simulation       Lecture#6: 13
Prototype
customer-
process
routine for
a single-
server
queueing
system




ICS41: Computer Modeling and Simulation   Lecture#6: 14
Classification of Simulation Software
(aspects of simulation packages)
• Common Modeling Elements:
        •   Entity
        •   Attributes
        •   Resources
        •   Queue




 ICS41: Computer Modeling and Simulation   Lecture#6: 15
   Modeling Elements

Type of System      Entities       Attributes     Resources      Queues

Manufacturing       Part           part #, due    Machines,      Queues or
                                   date           workers        buffers

Communications      Message        Destination,   Nodes, links   Buffers
                                   message
                                   length
Airport             Airplane       Flight #,      Runways,       Queues
                                   weight         gates

Insurance Agency    Application,   Name, policy   Agents, clerks queues
                    claims         #, amount




     ICS41: Computer Modeling and Simulation              Lecture#6: 16
Desirable Software Features

•    General capabilities
•    Hardware and software considerations
•    Animation
•    Statistical features
•    Customer support and documentation
•    Output reports and plots



    ICS41: Computer Modeling and Simulation   Lecture#6: 17
Desirable Software Features
(General Capabilities)
• Modeling flexibility
        • ability to define and change attributes for entities
          and global variables
        • ability to create new modeling constructs and
          modify existing ones
• Ease of use
        • modeling constructs that are not too primitive and
          not too macro.




 ICS41: Computer Modeling and Simulation        Lecture#6: 18
Desirable Software Features
(General Capabilities)
• Good debugging aids
        • allows the user to:
             – follow a single entity through the model
             – see the state of the model every time a particular
               event occurs
             – set the value of certain attributes or variables.

• Fast model execution speed
• User-friendly model “front-ends”



 ICS41: Computer Modeling and Simulation           Lecture#6: 19
Desirable Software Features
(General Capabilities)
• Ability to import data from (and export
  data to) other applications
• Automatically simulate different scenarios
  that iterate on some model parameters.
• Easily initialized in a nonempty and idle
  state.




 ICS41: Computer Modeling and Simulation   Lecture#6: 20
Desirable Software Features
(General Capabilities)
• State of the simulation can be saved at
  the end of a run
• Cost




 ICS41: Computer Modeling and Simulation   Lecture#6: 21
Desirable Software Features
(Hardware & Software Requirements)
•    Computer platforms
•    Compatible across platforms
•    RAM required
•    Operating system supported




    ICS41: Computer Modeling and Simulation   Lecture#6: 22
Desirable Software Features
(Animation & Dynamic Graphics)

    • Uses of animation:
             • communicating the essence of a simulation
               model
             • debugging the simulation computer program
             • showing that a simulation model is not valid
             • suggesting improved operational procedures
               for a system
             • training operational personnel
             • promoting communication among the project
               team


 ICS41: Computer Modeling and Simulation      Lecture#6: 23
Desirable Software Features
(Animation & Dynamic Graphics)
• Types of Animation:
   – concurrent animation
   – post-processed animation




 ICS41: Computer Modeling and Simulation   Lecture#6: 24
Concurrent Animation

• animation is displayed at the same time
  that the simulation is running




 ICS41: Computer Modeling and Simulation   Lecture#6: 25
Post-processed Animation

• state changes in the simulation are
  saved to a disk file and used to drive the
  graphics after the simulation is over.




 ICS41: Computer Modeling and Simulation   Lecture#6: 26
Desirable Software Features
(Animation & Dynamic Graphics)
• Desirable features:
   –   default animation
   –   create high-resolution icons
   –   smooth movement of icons
   –   speed up or slow down the animation
   –   named animation views
   –   vector-based vs pixel-based graphics
   –   three-dimensional animation
   –   import drawings/clip arts




 ICS41: Computer Modeling and Simulation      Lecture#6: 27
Desirable Software Features
(Statistical Capabilities)
• Must have a good random generator
• Empirical (or user-defined) distribution
  will be used as an alternative
• Independent replications (or runs) of the
  simulation model
        • each run uses separate sets of different random
          numbers;
        • each run uses the same initial condition
        • each run resets the statistical counters.


 ICS41: Computer Modeling and Simulation      Lecture#6: 28
Desirable Software Features
(Customer Support & Documentation)
• Customer Support
        • provide public training
        • technical support
• Good Documentation
        • possible to learn w/o taking formal training course
        • context-dependent online help




 ICS41: Computer Modeling and Simulation       Lecture#6: 29
Desirable Software Features
(Output Reports and Graphics)
•     standard reports
•     customize reports
•     histogram
•     time plots
•     results be stored in a database
•     plotted in a single graph
•     export individual model output observations




    ICS41: Computer Modeling and Simulation   Lecture#6: 30
General-Purpose Simulation Software

•    Arena
•    Extend
•    AweSim
•    MODSIM III
•    Symix, etc.




    ICS41: Computer Modeling and Simulation   Lecture#6: 31
Application-Oriented Simulation
Software
• Manufacturing
        •    AutoMod
        •   AutoSched
        •   Extend + Manufacturing
        •   Arena Packaging Edition, etc
• Communications Networks
        • COMNET III
        • IT DecisionGuru
        • OPNET Modeler




 ICS41: Computer Modeling and Simulation   Lecture#6: 32
Application-Oriented Simulation
Software
• Process Reengineering & Services
        •   Arena Business Edition
        •   Extend + BPR
        •   ProcessModel
        •   ServiceModel
        •   SIMPROCESS
• Health Care
        • MedModel




 ICS41: Computer Modeling and Simulation   Lecture#6: 33
Application-Oriented Simulation
Software
• Call Centers
        • Arena Call Center Edition
• Animation (standalone)
        • Proof Animation




 ICS41: Computer Modeling and Simulation   Lecture#6: 34

				
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