Simulation Software

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Simulation Software
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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

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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

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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

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Classification of Simulation Software (aspects of
simulation packages)

• General-Purpose vs. Application-Oriented
  Simulation Package
• Simulation Languages
• Application-oriented Simulators

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Simulation Languages

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

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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.

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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.

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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.

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Classification of Simulation Software (aspects of
simulation packages)

• Modeling Approaches
• Event-scheduling Approach
• Process Approach

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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

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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.

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Process Approach
Process describing the flow of entity through a
system
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Prototype customer-process routine for a
single-server queueing system
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Classification of Simulation Software (aspects of
simulation packages)

• Common Modeling Elements
• Entity
• Attributes
• Resources
• Queue

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Modeling Elements
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Desirable Software Features

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

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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.

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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

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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.

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Desirable Software Features (General
Capabilities)

• State of the simulation can be saved at the end
  of a run
• Cost

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Desirable Software Features (Hardware
Software Requirements)

• Computer platforms
• Compatible across platforms
• RAM required
• Operating system supported

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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

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Desirable Software Features (Animation
Dynamic Graphics)

• Types of Animation
• concurrent animation
• post-processed animation

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Concurrent Animation

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

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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.

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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

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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.

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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

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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

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General-Purpose Simulation Software

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

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Application-Oriented Simulation Software

• Manufacturing
• AutoMod
• AutoSched
• Extend Manufacturing
• Arena Packaging Edition, etc
• Communications Networks
• COMNET III
• IT DecisionGuru
• OPNET Modeler

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Application-Oriented Simulation Software

• Process Reengineering Services
• Arena Business Edition
• Extend BPR
• ProcessModel
• ServiceModel
• SIMPROCESS
• Health Care
• MedModel

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Application-Oriented Simulation Software

• Call Centers
• Arena Call Center Edition
• Animation (standalone)
• Proof Animation