An Improved Imperialist Competitive Algorithm for Reentrant Flow Shop Scheduling

This study considers chain reentrant flow shop scheduling problem which exists in real-world industries. Each job visits all machines in a fixed order and return back to the first machine for its last operation. The goal of the problem is to decide the processing sequence of jobs on each machine in order to minimize makespan and total tardiness simultaneously. An improved imperialist competitive algorithm (IICA) is proposed, in which new solutions are generated by the revolution of imperialists, assimilation and revolution of colonies. Some new strategies are also adopted to construct initial empires and implement imperialist competition. A number of experiments are conducted to test the performance of IICA. The computational results demonstrate that IICA can provide promising results for the considered problem.