Centralized and decentralized optimisation techniques for the flexible job shop scheduling problem

This paper proposes two Multi-agent approaches based on a tabu search method for solving the flexible Job Shop scheduling problem. The characteristic of the latter problem is that one or several machines can process one operation so that its processing time depends on the machine used. Such a generalization of the classical problem makes it more and more difficult to solve. The objective is to minimize the makespan or the total duration of the schedule. The proposed models are composed of three classes of agents: Job agents and Resource agents and an Interface agent. According to the location of the tabu search core, two versions have been proposed. The first one places the optimisation method only on the Interface agent whereas the second associates to each Resource agent its own optimisation process.