Local search in complex scheduling problems

Abstract

In this paper different local search procedures are applied to a genetic algorithm for a complex hybrid flexible flow line problem. General precedence constraints among jobs are taken into account, as are machine release dates, time lags and sequence dependent setup times; both anticipatory and non-anticipatory. Although closely connected to real-world problems, this combination of constraints is hardly treated in the literature. This paper presents a study of the behaviour of local search for such a complex problem. A combination of the local search variants is presented. Comprehensive statistical experiments indicate that substantial improvements in solution quality can be reached. © Springer-Verlag Berlin Heidelberg 2007.