Bi-objective Optimization for Just in Time Scheduling: Application to the Two-Stage Assembly Flow Shop Problem

Abstract

This paper considers a two-stage assembly flow shop problem (TAFSP) where m machines are in the first stage and an assembly machine is in the second stage. The objective is to minimize a weighted sum of earliness and tardiness time for n available jobs. JIT seeks to identify and eliminate waste components including over production, waiting time, transportation, inventory, movement and defective products.Two-stage assembly flow shop is a combinational production system in which different parts are manufactured on parallel machines independently. This system can be used as a method to produce a variety of products through assembling and combining different set of parts. We apply e-constraint method as an exact approach to validate the proposed model and to obtain fronts of the solutions in the solution spaceThe goal of the proposed problem is trade off between two objectives, minimization makespan and total weighted tardiness and earliness. To analyze effects of n and m factors on the efficiency and performance of the proposed algorithm, we calculate the complexity of sub problems based on factors n and m and the computational results demonstrate that the computational time increases with increasing in n and m, in other words, complexity of the problem increases.