General Remarks on Modelling

Abstract

As previously mentioned, a model is a system of mathematical equations (algebraic, differential, partial differential, integral) allowing all the known experimental data to be taken into account. A model must involve:

• the best possible understanding of the biological phenomenon

• the possibility of functioning (system optimization)

In the following we shall see how to distinguish between the state variables (describing the system evolution) and the control variables (acting on the system). Models are of two main types:

• a) knowledge models where mathematical equations are obtained as translations of the physical laws of the system, and

• b) simulation models giving a priori equations whose coefficients must be identified from available experimental data.