Simulation and Modeling of Systems of Systems

Chapter 2

Principles of Modeling 1

2.1. Introduction to modeling

Modeling is the activity by which a model is designed. In this chapter, we shall see how a model can be designed and some of the most widespread types of model. Note that modeling for simulation obeys more or less the same rules as modeling in complex systems engineering, albeit with certain specific constraints which, although they are not limited to the field of simulation, are particularly strong in this case; these include the validation, the choice of levels of refinement (which has an impact on the model), and the need to take installation (e.g. the capacities of the target computer platform) into account.

We start by laying down some basic principles of modeling:

– The model is constructed to solve a specific problem and is, therefore, subjective. A model, although representative of a system, is not necessarily valid or relevant.

– The same problems occur again. There is much to be gained by systematically checking whether the model has already developed with similar principles. If so, attempts should be made to modify the existing model, assuring that its validity and availability can be guaranteed.

Continuing with the same principle, a model should be able to exist, as hypotheses concerning a system may change (particularly in the case of studies being carried out for a future system) or the system itself may exist (in the case of a simulation used while the system is already operational, e.g. a flight simulator ...