3. What are the techniques for modeling and representing a system?

A system is an abstract concept; only models of future products, services and organizations can represent the characteristics of your system. A single global model cannot represent all the characteristics of the system. This is why complementary types of model are used. The current difficulty lies in obtaining a coherent set of models. Only the main characteristics of a system are discussed here, leaving aside models relating to the different technologies used to build it.