GPS-X Technical Reference

Modelling Fundamentals 18
Simulation
Simulation is to
a model what
experimentation
is to a system
Again, many different definitions exist for the term “simulation”. One of the simplest
definitions is: A simulation is an experiment performed on a model Again, this does not
imply that the simulation is performed on a computer; however, the vast majority of
engineering simulations are performed using a computer program. A mathematical
simulation is a coded description of an experiment with a reference point to the model to
which this experiment is to be applied. The goal is to be able to experiment with models
as easily and conveniently as with real systems. It is desired to be able to use the
simulation tools as easily as a control chart in the operation of a facility.
While the scientist is normally happy to observe and understand the world, that is,
creating a model of the world, the engineer (applied scientist) wants to modify it to
his/her advantage. While science is analysis, the essence of engineering is control and
design. Thus, simulation can be used for analysis and for design.
Why is Simulation Important
Except by experimenting with the real system, simulation is the only technique
available for the analysis of arbitrary system behaviour. The typical scenario of
scientific discovery is as follows:
Simulation Tools
1. Perform an experiment on the real system and extract data to gather
knowledge (understanding of the cause and effect relationship of the real
world).
2. Postulate a number of hypotheses related to the data.
3. Simplify the problem to help make the analysis tractable.
4. Perform a number of simulations with different experimental parameters
to verify that the simplifying assumptions are justified.
5. Analyze the system, verify the hypotheses and draw conclusions
6. Simulations are performed to draw conclusions.
A wide variety of simulation tools are available to help you in this task.
Assuming the reader is particularly interested in the dynamic modelling of
wastewater treatment, the tools appropriate for this task are emphasized.
GPS-X Technical Reference