Author(s)

A. Genccf, V. Lacagnina, A. Masnata & G. Pecorella

Abstract

Job shop scheduling by a parallel approach A. Genccf, V. Lacagnina", A. Masnata", G. Pecorella^ "Dipartimento di Tecnologia e Produzione Meccanica ^Istituto di Automatica e Sistemistica Universitd degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy ABSTRACT The paper deals with a parallel approach to job shop scheduling by a branch and bound methodology using the lower bound proposed by Ashour and Hiremath. The optimal solution is achieved by an iterative-reductive strategy. At each iteration the algorithm investigates the conflict intervals and it selects a subset of the possible solutions. The makespan value, achieved by the parallel processes, gives the upper limit for the admissible lower bound of the intermediate solutions. Furthermore the best makespan reached by each iteration is reused as a filter to reduce the complexity of the next iteration. The computation is speeded up by a parallel implementation, giving the possibility of d

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