Scheduling to minimize the sum of weighted flowtime and weighted tardiness of jobs in a flowshop with sequence-dependent setup times

Efficient heuristics for scheduling jobs in a static flowshop with sequence-dependent setup times of jobs are presented in this paper. The objective is to minimize the sum of weighted flowtime and weighted tardiness of jobs. Two heuristic preference relations are used to construct a good heuristic permutation sequence of jobs. Thereafter, an improvement scheme is implemented, once and twice, on the heuristic sequence to enhance the quality of the solution. An exisiting heuristic, a random search procedure and a greedy local search are used as benchmark methods for relatively evaluating the proposed heuristics. An extensive performance analysis has shown that the proposed heuristics are computationally faster and more effective in yielding solutions of better quality than the benchmark procedures.