Balbi, J.H with N. Balbi, G. Girolami, P. Orenga and G. Simonnot, "Identification of Dynamic Systems", 1986
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In this paper, the dominant approach to the modelling of physical systems is described: it uses local laws and powerful numerical tools. For linear problems, it leads to eigenvalues and eigenvectors, in a suitable functional space, from which it is possible to construct the response to any excitation using the Green's resolvant. This approach has led to important progress in engineering physics. Nevertheless, a systemic approach is useful in physics and irreplaceable for living systems. This second way uses global laws of the phenomenon in addition with a dynamical identification of the system using some adequate experiments. We illustrate this method on the modelling of a solar plant, which is correctly represented by a simple ordinary differential equation.