“…Some important examples include: 1-out-of-2:G systems with common cause failures and human errors [7], with imperfect sensing and switching [8], 2-out-of-5:G systems with common cause failures and replacements [9], k-out-of-n:G warm standby system with r repair facilities [10], [11], with balking and reneging components [12], with components with multiple failure modes [13], with unreliable repair facilities [14], warm standby systems with two nonidentical components and failure of switching [15], warm standby subsystems with two nonidentical components and in series connection with another subsystem [16]. In cases of nonexponential distributions, supplementary variable techniques [17]- [22] and PH distribution techniques [23], [24] can be used. Moreover, warm standby systems with s-identical components can be solved by developing iterative equations for state probabilities by event decomposition [25], [26].…”