Adaptação e análise de desempenho de heurísticas para minimização do gap em problemas de flowshop

Abstract

There are many articles, works and researches regarding scheduling, with a wide variety of optimization objectives, such as makespan, flowtime, delays, etc. However, there is a field almost unexplored, and it is the association of the minimization of the gap between the beginning and ending of a job n and n+1 on a machine m. This gap can produce a series of inconveniences to a system made of multiples machines, just as idleness of the machines, making significant impacts to the energy performance and costs of an industry. The present research has the objective of associating the minimization of total gap, in a flowshop system, with the objective function of makespan minimization, adding the lower impact possible to the makespan. Starting with a heuristic that combines the methods LPT and NEH, was created a biobjective function that achieved satisfying results, with potential to increase machine efficiency in a productive environment significantly. Within a gap application of 10% and 25% into the objective function, it was found the best techinal result, with a slight increase of makespan, but significant reductions on total gap.