A New Hybrid Intelligent Algorithm for Fuzzy Multiobjective Programming Problem Based on Credibility Theory

Table 2

Nomenclature used in the mathematical model (22).

Variable	Signification
𝑠	Number of subsystems
𝑖	Index of a subsystem
𝜆𝑖	Fuzzy variable of the failure rate of components in subsystem 𝑖 with known membership function
𝜆	𝜆=(𝜆1,𝜆2,…,𝜆𝑠)
𝜇𝑖	Fuzzy variable of the repair rate of components in subsystem 𝑖 with known membership function
𝜇	𝜇=𝜇1,𝜇2,…,𝜇𝑠
𝑘𝑖	Number of components in subsystem 𝑖
𝑘	𝑘=𝑘1,𝑘2,…,𝑘𝑠
𝑙𝑘, 𝑢𝑘	Vector of minimum and maximum number of components allowable in each subsystem
𝑎𝑖, 𝑏𝑖, 𝑝𝑖, 𝑞𝑖	Coefficients of the cost function which can be obtained from maintenance database