Comparing scheduling rules for flexible flow lines

This paper explores scheduling flexible flow lines with sequence-dependent setup times. Three major types of heuristics are explored. Insertion heuristics (based on insertion heuristics for the traveling salesman problem) attempt to simultaneously equalize workload on all processors at a stage, and minimize total or single-stage flowtimes. Johnson's algorithm for two-stage flow shops and its heuristic extensions to m-machine flow shops are modified for parallel processors and the flexible flow-line environment. A set of naive greedy heuristics is investigated for comparison purposes. The performance of the heuristics is compared on a set of test problems. Results indicate the range of conditions under which each method performs well. (C) 2003 Elsevier B.V. All rights reserved.