Energy-Aware Multiple State Machine Scheduling for Multiobjective Optimization

Optimising the energy consumption is one of the most important issues in scheduling nowadays. In this work we consider a multi-objective optimisation for the well-known job-shop scheduling problem. In particular, we minimise the makespan and the energy consumption at the same time. We consider a realistic energy model where each machine can be in Off, Stand-by, Idle or Working state. We design an effective constraint-programming approach to optimise both the energy consumption and the makespan of the solutions. Experimental results illustrate the potential of the proposed method, outperforming the results of the current state of the art in this problem.