Lecture 4
ICS41 Computer Modeling and
Simulation
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Classifications of Simulation Software
Application-Oriented Simulation Package
General-Purpose Simulation Language
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Application-
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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Application-
Application-Oriented Simulation Package
utilizes mathematical models to replicate the
behavior of an actual phenomenon
ex:
◦ CircuitLogix
Schematic editor
SPICE simulator
on-screen waveforms
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Application-
Application-Oriented Simulation Package
Advantages:
◦ 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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Application-
Application-Oriented Simulation Package
Manufacturing
AutoMod
AutoSched
Extend + Manufacturing
Arena Packaging Edition, etc
Communications Networks
COMNET III
IT DecisionGuru
OPNET Modeler
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Application-
Application-Oriented Simulation Package
Process Reengineering & Services
Arena Business Edition
Extend + BPR
ProcessModel
ServiceModel
SIMPROCESS
Health Care
MedModel
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Application-
Application-Oriented Simulation Package
Call Centers
Arena Call Center Edition
Animation (standalone)
Proof Animation
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General-
General-Purpose Simulation Package
can be used for any application, but might
have special features for certain ones.
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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General-
General-Purpose Simulation Package
Advantages:
◦ 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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General-
General-Purpose Simulation Package
Extend
AweSim
MODSIM III
Symix, etc.
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AweSim Animation with Multiple Windows
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Extend Call Center Model with Hierarchical Blocks
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Simulation Software Modeling Approaches
Event-scheduling Approach
Process Approach
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Event-
Event-Scheduling Approach
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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Simulation Software Modeling Elements
Entity
Attributes
Resources
Queue
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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 Application, Name, policy Agents, queues
Agency claims #, amount clerks
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General capabilities
Hardware and software considerations
Animation
Statistical features
Customer support and documentation
Output reports and plots
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General Capabilities
Modeling flexibility
ability to define new modeling structures and/or
modify existing ones
Ease of use
modeling constructs that are not too primitive and
not too macro.
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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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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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General Capabilities
State of the simulation can be saved at the
end of a run
Cost
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Hardware and Software Requirements
Computer platforms
Compatible across platforms
RAM required
Operating system supported
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Animation and 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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Animation and Dynamic Graphics
Types of Animation:
◦ concurrent animation
◦ post-processed animation
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Types of Animations
Concurrent Animation
◦ animation is displayed at the same time that
the simulation is running
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
◦ animation is activated after all the processing
and evaluation are done.
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Animation and 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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Statistical Capabilities
Must have a good random generator
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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Customer Support and 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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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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