Microelectro,. Reliab., Vol. 31, No. 2/3, pp. 323-335, 1991. 0026-2714/9153.00 + .00 Printed in Great Britain. © 1991 Pergamon Press plc MULTICRITERIA OPTIMIZATION FOR CMMD RELIABILITY AND REDUNDANCY ALLOCATION IN SYSTEMS EMPLOYING MIXED REDUNDANCIES KRISHNA B. MISRA and USHA SHARMA Reliability Engineering Centre, Indian Institute of Technology, Kharagpur-72|302, West Bengal, India (Received for publication 2 April 1990) AB|TRACT The present paper provides a new mathematical formulation of a combined reliability and redundancy allocation involving multiple objective functions in the reliability design of a system employing mixed type of redundancy. The paper proposes an easily computerizable procedure for solving a variety of design problems. The proposed solution technique is a combination of the direct search technique [9,10] and a random search procedure for optimizing redundancy and reliability at the same time at each subsystem and uses multicriteria optimization procedure based on min-max approach [11,12] for obtaining Pareto optimal solutions. The procedure is illustrated through several examples. A general computer code, called ESMOP (Efficient Search Multi-Objective Programming), for the use on IBM compatible PCs has also been developed. The code takes into account all kinds of redundancies including multiple discrete choices for component reliabilities, and a wide variety of resource coefficients and constraint functions. I. INTRODUCTION For the first time, the idea of combined reliability and redundancy allocation in reliability design of a system was introduced by Misra and Ljubojevic [I] in 1973. The consideration of such a problem results into a mixed integer nonlinear programming [i]. Later 323