Model-based Systems Architecting

3CESAM Framework

3.1. Elements of systemics

Before going further, we first need to introduce the notions of interface and of system environment. These elements of systemics will indeed be useful for presenting further the CESAM framework. We refer to Definition 1.1, Definition 1.2 and section 1.1 for the fundamentals of systemics, that is, the core definitions of a system, on which the CESAM framework is constructed.

3.1.1. Interface

The concept of interface is the first key systemic concept¹ that we need to present. In this matter, let us thus now recall that an interface models an interaction, an exchange, an influence or a mutual dependence between at least two systems (some interfaces may indeed be complex and involve several systems²). Beware that an interface may not necessarily have a concrete implementation: it is just a way of expressing the relative impacts that different systems have each on the others³.

With respect to a given system S, interfaces may then be either external, when they are involving the considered system and some other external systems, or internal, when they are only relative to sub-systems of S. Figure 3.1 illustrates this notion on the electronic toothbrush example by showing two external interfaces between the toothbrush and the end-user (here one with his/her mouth, the other with his/her hand) and several internal toothbrush interfaces (i.e. two mechanical interfaces and one inductive interface between the base and the body of the toothbrush). ...