Title: The parallel machine scheduling problem with variable demand and a pre-defined lot size

Authors: Alex J. Ruiz-Torres; José Humberto Ablanedo-Rosas; Johnny C. Ho

Addresses: Facultad de Administración de Empresas, Departamento de Gerencia, Universidad de Puerto Rico – Rio Piedras, San Juan, PR 00931-3332, USA ' Department of Information and Decision Sciences, College of Business Administration, University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, USA ' Department of Management and Marketing, Turner College of Business and Computer Science, Columbus State University, Columbus, GA 31907, USA

Abstract: In this paper, we consider the problem of scheduling multiple product types in parallel machines given variable demand across a multi-period planning horizon. Production is organised around a pre-defined lot size as frequently arises in the pharmaceutical industry. The problem class falls within the big bucket category with a single level of production, it is capacitated and considers multiple parallel machines. There is no deterioration of the items within the planning horizon, the demand is dynamic and deterministic. A complex set-up structure is assumed, and backordering is allowed. The objective is to find a production schedule that minimises holding, setup and backordering costs. Four heuristics are developed to generate the production plan. Computational experiments demonstrate that the solutions generated are close to optimal for small problems, and that the methods have robust performance for larger problems.

Keywords: production planning; parallel machine scheduling; lot sizing; heuristics; pharmaceutical industry.

DOI: 10.1504/IJOR.2012.046341

International Journal of Operational Research, 2012 Vol.14 No.1, pp.1 - 30

Published online: 11 Jan 2015 *

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