Abstract
A hybrid genetic algorithm is proposed in this paper to minimize the makespan and the total flowtime in the no-wait flowshop scheduling problem, which is known to be NP-hard for more than two machines. The Variable Neighborhood Search is used as an improvement procedure in the last step of the genetic algorithm. First, comparisons are provided with respect to several techniques that are representative of the previous works in the area. Then, we compare the results given by three proposed algorithms. For the makespan criterion as well as for the total flowtime, the computational results show that our algorithms are able to provide competitive results and new best upper bounds.