bicriteria scheduling in hybrid flow shop with unrelated parallel machines

this study considers scheduling in hybrid flow shop environment with unrelated parallel machines for minimizing mean of job's tardiness and mean of job's completion times. this problem does not study in the literature, so far. flexible flow shop environment is applicable in various industries such as wire and spring manufacturing, electronic industries and production lines. after modeling the problem as a mixed integer programming model, three heuristics named cluster, h1 and h2 is proposed for solving it. the first heuristic (cluster) algorithm utilizes clustering methods for determining sequence of jobs. the second and third heuristics (h1 and h2) determine sequence of jobs with using spt and edd rules, respectively. the experimental results of study show that cluster algorithm outperforms h1 and h2.