An approximate method for computing performance-related reliability

In this paper we study the computation of the performance-related reliability (PRR) of gracefully degrading systems with reconfiguration coverage 1. When the number of units making up the system, N, tends to infinity, the behaviour of the system can be modeled as a diffusion process, and the PRR of the system can be computed by solving Kolmogorov backward equation. In this paper we point out that when N is large enough but not infinite, Kolmogorov backward equation is still applicable for computing PRR after rescaling time, changing the initial probability density function of the process and modifying the required performance level. The method has been applied in several examples, and the results are satisfactory.<>