1.
Problem formulation
Every study
begins with a statement of the problem, provided by policy makers. Analyst
ensures it is clearly understood. If it is developed by analyst policy makers
should understand and agree with it.
2.
Setting of objectives and overall project plan
The objectives
indicate the questions to be answered by simulation. At this point a
determination should be made concerning whether simulation is the appropriate
methodology. Assuming it is appropriate, the overall project plan should
include:
- A statement of the alternative systems
- A method for evaluating the effectiveness of these alternatives
- Plans for the study in terms of the number of people involved
- Cost of the study
- The number of days required to accomplish each phase of the work with the anticipated results.
3. Model conceptualization
The construction
of a model of a system is probably as much art as science. The art of modeling
is enhanced by ability:
- To abstract the essential features of a problem
- To select and modify basic assumptions that characterizes the system
- To enrich and elaborate the model until a useful approximation results
Thus, it is best
to start with a simple model and build toward greater complexity. Model
conceptualization enhances the quality of the resulting model and increases the
confidence of the model user in the application of the model.
4. Data collection
There is a
constant interplay between the construction of model and the collection of
needed input data. It is done in the early stages. Objective kind of data is
collected.
5. Model
translation
Real-world
systems result in models that require a great deal of information storage and
computation. It can be programmed by using simulation languages or special
purpose simulation software. Simulation languages are powerful and flexible.
Simulation software models development time can be reduced.
6. Verified
It pertains to
the computer program and checking the performance. If the input parameters and logical
structure are correctly represented, verification is completed.
7. Validated
It is the
determination that a model is an accurate representation of the real system. It
is achieved through calibration of the model. The calibration of model is an iterative
process of comparing the model to actual system behavior and the discrepancies
between the two.
8. Experimental
Design
The alternatives
that are to be simulated must be determined. Which alternatives to simulate may
be a function of runs? For each system design, decisions need to be made
concerning
- Length of the initialization period
- Length of simulation runs
- Number of replication to be made of each run
9. Production runs
and analysis
They are used to
estimate measures of performance for the system designs that are being
simulated.
10. More runs
Based on the
analysis of runs that have been completed, the analyst determines if additional
runs are needed and what design those additional experiments should follow.
11. Documentation
and Reporting
Two types of
documentation:
i. Program documentation
ii. Process documentation
i. Program documentation
ii. Process documentation
i. Program
documentation
Can be used
again by the same or different analyst’s to understand how the program
operates. Further modification will be easier. Model users can change the input
parameters for better performance.
ii. Process
documentation
Gives the
history of a simulation project. The result of all analysis should be reported
clearly and concisely in a final report. This enables to review the final
formulation and alternatives, results of the experiments and the recommended solution
to the problem. The final report provides a vehicle of certification.
12. Implementation
Success depends on the previous steps. If the model
user has been thoroughly involved and understands the nature of the model and its
outputs, likelihood of a vigorous implementation is enhanced. The simulation
model building can be broken into 4 phases.
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