Jabali, OlaGendreau, MichelJans, RafTaş, Duygu2019-02-282019-02-282019-02-282019-02-282019Taş, D., Gendreau, M., Jabali, O., & Jans, R. (January 01, 2019). A capacitated lot sizing problem with stochastic setup times and overtime. European Journal of Operational Research, 273, 1, 146-159.0377-2217https://hdl.handle.net/20.500.11779/722http://dx.doi.org/10.1016/j.ejor.2018.07.032Duygu Taş (MEF Author)In this paper, we study a Capacitated Lot Sizing Problem with Stochastic Setup Times and Overtime (CLSPSSTO). We describe a mathematical model that considers both regular costs (including production, setup and inventory holding costs) and expected overtime costs (related to the excess usage of capacity). The CLSP-SSTO is formulated as a two-stage stochastic programming problem. A procedure is proposed to exactly compute the expected overtime for a given setup and production plan when the setup times follow a Gamma distribution. A sample average approximation procedure is applied to obtain upper bounds and a statistical lower bound. This is then used to benchmark the performance of two additional heuristics. A first heuristic is based on changing the capacity in the deterministic counterpart, while the second heuristic artificially modifies the setup time. We conduct our computational experiments on well-known problem instances and provide comprehensive analyses to evaluate the performance of each heuristic. (C) 2018 Elsevier B.V. All rights reserved.eninfo:eu-repo/semantics/closedAccessSample average approximationStochastic setup timesHeuristicsProductionLot sizingArticle10.1016/j.ejor.2018.07.0322-s2.0-85051522557