A shuffled frog-leaping algorithm for job shop scheduling with outsourcing options

In this paper, job shop scheduling problem with outsourcing options is considered and a novel shuffled frog-leaping algorithm (SFLA) is presented to minimise total tardiness under condition that total outsourcing cost does not exceed a given upper bound. In SFLA, a tournament selection-based method is used to decompose the whole population into some memeplexes, the search process in each memeplex is done on the best solution of the memeplex and composed of the global search step and the multiple neighbourhood search step. SFLA is tested on a number of instances and compared with some methods from the literature. Computational results validate the promising performance of SFLA on the considered problem.