COBEM99

SR22 Otimização de Processos

Title:

STUDY AND APPLICATIONS OF SCHEDULING ALGORITHMS FOR MANUFACTURING SYSTEMS WITH PRODUCTION BOTTLENECKS

Summary :

THE MANUFACTURING SYSTEMS PRESENT IN ITS STRUCTURE SITUATIONS IN WHICH A CERTAIN MACHINE BECOMES MORE REQUESTED BY THE GLOBAL PROCESS OF PRODUCTION. THE LARGE USE OF THAT RESOURCE DRIVES, FREQUENTLY, TO PROBLEMS IN THE REMAINING OF THE LINE AS BACK PAYMENTS, FLAWS IN ANOTHER EQUIPMENTS (THAT CAN BE CAUSED BY THE IMPROPER ACTIVATION, BEFORE OR AFTER THE SCHEDULED TIME), OR EVEN THE DEMAND ELEVATION FOR ANOTHER RESOURCE BEFORE WELL EMPLOYEE. ON THE OTHER HAND, IT IS NOT UNCOMMON, IN THE INDUSTRY OF MECHANICAL PIECES, THAT SHORT DELIVERY PERIODS, HIGH DEMANDS AND THE PRODUCTION STRUCTURES ITSELF RESTRICT THE PROBLEM IN SUCH A WAY THAT BECOMES DIFFICULT, IN A SCHEDULING APPROACH, TO DETERMINE A OPTIMAL SOLUTION THAT ASSISTS TO THE RESTRICTIONS AND, AT THE SAME TIME, AN OBJECTIVE FUNCTION. IN THE AMBIT OF THE CSP HEURISTICS (CONSTRAINT SATISFACTION PROBLEM), THE RESULTS OBTAINED BY KENG (1988) CAN BE CONSIDERED IN A FIRST MOMENT. IT IS PROPOSED AN HEURISTIC APPROACH THAT IS BASED ON CRITICALITY CALCULATIONS TO DETERMINE HOW PROBLEMATIC CERTAIN RESOURCE CAN BE. THE OPT HEURISTICS (OPTIMIZATION PROBLEM TECHNIQUES), BY ITS TURN, ARE BASED IN GOLDRATT, AND LATER ON DEVELOPED BY OTHER AUTHORS, AMONG THEM MORTON (1993). IT IS INTENDED, IN THIS WORK, THROUGH A REVISION AND STUDY OF ONE OF THE METHODS FOUND IN THIS LAST AUTHOR S WORK FOR BOTTLENECK TREATMENT (FORECAST MYOPIC DISPATCH) AND OF THE HEURISTIC DEVELOPED BY KENG FOR JOB SHOP, TO DELINEATE A STRATEGY OF A HYBRID APPROACH FOR THE OPTIMIZATION OF SUCH "CRITICAL" RESOURCES, ASSISTING TO THE RESTRICTIONS "STRONG" COMING OF THE MENTIONED EXTERNAL FACTORS. THE CONCEPTS RELATED TO THE MENTIONED WORKS SUPPLYING A GENERAL VISION WILL BE INTRODUCED SHORTLY AND THEY WILL HAVE ITS IDEAS GATHERED IN ONLY ONE HEURISTIC, WITH ITS OWN CHARACTERISTICS.

Author :

Barreto, Marcos R. P.
Batocchio, Antonio 0
Dagnone, Carlos Augusto Fernandes

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