en و موضوعات مربوط Other Related Subject پژوهشي Research Flexible flow shop scheduling problem (FFS) with unrelated parallel machines contains sequencing in flow shop where, at any stage, there exists one or more processors. The objective consists of minimizing the maximum completion time. Because of NP-completeness of FFS problem, it is necessary to use heuristics method to address problems of moderate to large scale problem. Therefore, for assessment the quality of this heuristic, this paper develop a global lower bound on FFS makespan problems with unrelated parallel machines. lower bound, flexible flow shop, makespan, unrelated parallel machines 65 70 http://ijiepr.iust.ac.ir/browse.php?a_code=A-10-147-4&slc_lang=en&sid=1 Nasim Nahavandi n_nahavandi@modares.ac.ir 180031947532846002756 180031947532846002756 Yes Tarbiat Modares University Ebrahim Asadi Gangraj asadi_gangraj@modares.ac.ir 180031947532846002757 180031947532846002757 No