SciELO - Scientific Electronic Library Online

vol.20 issue1Algoritmo de programação de máquinas individuais com penalidades distintas de adiantamento e atrasoGRASP para o PQA: um limite de aceitação para soluções iniciais author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand




Related links


Pesquisa Operacional

Print version ISSN 0101-7438On-line version ISSN 1678-5142


MULLER, Felipe Martins  and  LIMBERGER, Sergio João. Uma heurística de trocas para o problema de sequenciamento de tarefas em processadores uniformes. Pesqui. Oper. [online]. 2000, vol.20, n.1, pp.31-42. ISSN 0101-7438.

This paper examines the nonpreemptive assignment of independent jobs to a system of uniform processors with the objective of reducing makespan, or the time required from the start of execution until all jobs are completed. We consider a set of n jobs, each having an execution time and a set of m³2 processors which are assumed to have different speeds (say s1 = 1£s2£ ... £sm). Since the problem of finding a minimal makespan has been show to be NP-hard, we develop a powerful interchange heuristic. The heuristic proposed is composed by three phases: initial assignment, job reassignment and job interchange. The main feature of this method is not perform a pre-classification of the tasks. Some comparison are made with other heuristic schemes and a lower bound that validates the results obtained. The heuristic achieve optimal solutions for several instances in a short computational time.

Keywords : scheduling problems; combinatorial optimization; heuristics.

        · abstract in Portuguese     · text in Portuguese     · Portuguese ( pdf epdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License