A modified Ant Colony algorithm for the Job Shop Scheduling Problem to minimize makespan

This paper presents a modified Ant Colony Optimization (ACO) algorithm for the Job Shop Scheduling Problem (JSSP) with makespan criterion. The traditional ACO algorithms can be simplified with the elimination of pheromone unimportant to the JSSP solution. Also, this paper suggests a new priority rule served as the heuristic information of the proposed algorithm. In order to improve the convergence and solution qualities of the proposed algorithm, the local search procedure based on the neighborhood of the JSSP is introduced. The experimental results indicate that the modified ACO algorithm in this paper is more concise and more effective than ACO algorithms. Furthermore, this paper discloses the existing problems of ACO algorithms for the JSSP.