On the timing to switch on the standby in kk-out-of-n:Gn:G redundant systems

Intuitively, activating the standby of a kk-out-of-nn:GG system to the working state at the last moment fully utilizes the redundancy and hence would result in a more reliable system; however, this is not always true as shown in a counterexample. This paper presents several scenarios under which, in comparison with the early switching, switching the standby to the working state at the last moment does improve system reliability more.