We treat the n-job, two-stage hybrid flowshop problem with one machine in the first stage and two different machines in parallel in the second stage. The objective is to minimize the makespan. We demonstrate that the problem is NP-complete. We formulate a dynamic program, which is beyond our grasp for problems of more than 15 jobs. We have conducted experimentation to evaluate the time performa...

This paper addresses the two-machine flowshop scheduling problemwith separate setup times to minimize makespan or total completion time (TCT). Setup times are relaxed to be random variables rather than deterministic as commonly used in the OR literature. Moreover, distribution-free setup times are used where only the lower and upper bounds are given. Global and local dominance relations are dev...

This paper considers a two-stage assembly flow shop scheduling problem. When all parts of each product are completed in the first stage, they are assembled into a final product on an assembly machine in the second stage. In order to reduce the delivery cost, completed products can be held until completion of some other products to be delivered in a same batch. The proposed problem addresses sch...

The flowshop scheduling problem with sequence dependent setup times is considered and shown to be NP-complete. A traveling salesman problem formulation is proposed for the case where jobs are processed continuously through the shop. These results are used to describe an approximate algorithm for the case where limited or infinite intermediate storage space is available to hold partially complet...

We address a complex scheduling problem arising in the wood panel industry with the objective of minimizing a quadratic function of job tardiness. The proposed solution strategy, which is based on an effective genetic algorithm, has been coded and implemented within a major Tunisian company, leader in the wood panel manufacturing. Preliminary experimental results indicate significant decrease o...

This paper deals with the no-idle permutation flowshop sequencing in order to minimize the total time of completing the schedule (makespan). A heuristic denoted by NB is introduced, which is compared with the best heuristics reported in the literature. An extensive computational experiment was carried out for the performance evaluation of the proposed heuristic. Experimental results clearly sho...

The progress of computer architecture has increased the necessity to design efficient scheduling algorithms according to the types of computer systems. We survey recent results of optimization and approximation algorithms for deterministic models of computer scheduling. We deal with identical, uniform and unrelated parallel processor systems, and flowshop systems. Optimality criteria considered...

This paper presents a genetic algorithm for a scheduling problem frequent in printed circuit board manufacturing: a hybrid flowshop with unrelated machines, sequence dependent setup time and machine availability constraints. The proposed genetic algorithm is a modified version of previously proposed genetic algorithms for the same problem. Experimental results show the advantages of using new c...