Optimal choice of standby modes in 1-out-of-N system with respect to mission reliability and cost

This paper considers a new type of optimization problems, the optimal standby mode selection problem in 1-out-of-N: G warm standby systems where multiple standby mode choices are available to provide different levels of operation readiness of standby elements and further to achieve a balance between fast restoration and low operation cost. Given the desired redundancy level and a fixed set of standby mode choices, the objective of the optimal system design is to choose a standby mode for each of redundant elements so as to minimize expected mission cost of the system subject to a certain reliability constraint. An iterative procedure is first suggested to evaluate system reliability and expected mission cost simultaneously. Based on the suggested evaluation algorithm, a genetic algorithm is then used as an optimization tool for solving the formulated optimal standby mode selection problem in 1-out-of-N: G warm standby systems. Examples are given to illustrate the considered evaluation and optimization problems as well as the proposed solution methodology.