Joint economic lot sizing problem for a three—Layer supply chain with stochastic demand (original) (raw)

The stochastic lot-sizing problem with lost sales: A chemical-Petrochemical case study

Journal of Manufacturing Systems, 2017

The recent evidence shows that production planning problems (e.g. lot sizing) in the manufacturing systems in general, and in the petrochemical sector in particular, can be very challenging. This fact, that the flows of chemical materials usually are continuous and the demands of chemical-petrochemical products inherently are uncertain, motivating researchers and practitioners to deal with stochastic lot sizing models in this manufacturing systems. This paper formulates such problems by taking distribution functions (discreet and continuous) into account. Moreover, lost sales are considered under the "static uncertainty" strategy. A solution methodology, additionally, is presented to determine the optimal timing and level of orders, when demand is defined by a discrete distribution function. To show the efficiency and effectiveness of proposed models and solution algorithm, a chemical-petrochemical case study as well as two other numerical example are described and solved.

Joint economic lot-sizing problem for a two-stage supply chain with price-sensitive demand

Scientia Iranica, 2016

This paper studies Joint Economic Lot-Sizing problem (JELS) for a singlevendor single-buyer system while demand is dependent on selling price. This problem is modeled for geometric shipment policy and a solution procedure is developed to nd a well approximation of the global optimal solution of the problem. Since the equalsize shipment policy or geometric shipment policy may yield more joint pro t compared to each other, the most important factor that a ects the break-even point of geometric and equal-size policies is determined. The JELS problem for dependent demand is also modeled for geometric-then-equal size and optimal shipment policies. Solution procedures to nd a well approximation of the global optimum of each problem are also developed for these models. The models and solution procedures for geometric, geometric-then-equal size, and shipment policies are novel in the literature. Numerical results of the models show considerable improvement in the joint pro t of the chain compared to lot-for-lot and equal-size shipment policies for chains with price-sensitive demand and it could be very interesting for supply chain coordinators and practitioners.

The joint economic lot sizing problem: Review and extensions

European Journal of Operational Research, 2008

With the growing focus on supply chain management, firms realize that inventories across the entire supply chain can be more efficiently managed through greater cooperation and better coordination. This paper presents a comprehensive and up-todate review of the joint economic lot sizing problem (JELP) and also provides some extensions of this important problem. In particular, a detailed mathematical description of, and a unified framework for, the main JELP models are given. Additionally, a comparative empirical study of the main policies proposed for JELP is conducted. The focus of this study is on assessing the deviation of these policies from the optimal solution. Studying the performance of different models provides additional insights that will help in justifying their use in more complex supply chain models that involve more stages or other practical considerations of interest. (C) 2007 Elsevier B.V. All rights reserved.