Properties and computation of interval availability of system

In this paper, we study the interval availability Aw(t) of a repairable system through an integral equation. We proved initial monotonicity of the interval availability, and derived lower bounds to Aw(t) and average availability. The limit of the interval availability is also obtained. A Block-by-Block algorithm for numerically computing Aw(t) is proposed. Various examples show the high accuracy and efficiency of this algorithm.