An enhanced integer simplicial optimization method for minimum cost spares for k-out-of-n systems

The authors report two enhancements to an integer simplicial optimization method developed for a spares allocation problem where it is necessary to minimize the spares cost of a k-out-of-n system configuration subject to an availability constraint. The first is an automated, simple, general method for generating an initial feasible good starting vector for optimization. This vector increases the likelihood of convergence to a global optimal solution and does not require homogenization of a suboptimum solution vector prior to restarting the optimization process of the penalty function for the lower values of the multipliers. The second is treatment of cases where the simplex strays into the feasible region. Results of testing the integer simplicial optimization procedure with the enhancements are compared to those obtained from methods developed specifically for dealing with this type of nonlinear integer problem. The tests were conducted for systems with various numbers of subsystems