Job shop scheduling problem with human operators in manufacturing process

This work deals with complex job shop scheduling problems, in which each task requires two different resources, i.e., machines and human operators. While a machine is specified for each task, there are in general more operators enabled to performing it. The problem is to assign and sequence the tasks for each operator and sequence them on each machine in order to minimize a certain objective function. We address both makespan minimization, for which we propose two different euristics, and the related cyclic scheduling problem, proposing a new MILP formulation.