4. KooN redundant architectures

4.1 Definition

By definition, the notion of redundancy refers to the existence, within an entity, of more than one means of accomplishing a required function. So, in order to reduce the probability of a system not fulfilling its safety function at the time it is called upon, one solution is to redundant some of the system's constituent elements.

A KooN redundancy is a so-called majority redundancy, such that a function is only ensured if at least K of the N existing means are in working order or in operation.

For example, 1oo2 redundancy comprises two elements, so that each can handle the safety function. In this way, the "dangerous" failure of both elements is necessary to ensure that a valid alarm signal is not adequately processed....