On the lower and upper bound for the steady-state availability of systems

Presents the lower and upper bound for the steady-state availability of a parallel-redundant system. The lower bound corresponds to failures occurring independently of the system state (even when the system is idle) and the upper bound corresponds to failures occurring only when the system is operational. The lower bound is known from the literature while the upper bound for the parallel-redundant system is a contribution of this paper. The computation of the upper bound presents an increased accuracy of the system analysis. However, a considerable effort is required to achieve this accuracy.