Abstract

This article examines a fundamental lot-sizing problem which arises in the context of a make-to-order remanufacturing environment. The problem setting is characterized by a stochastic used-item return process along with a stochastic remanufactured-item demand process faced by a remanufacturer. We explicitly take into account for all relevant costs, including the fixed costs (associated with remanufacturing of used-items and dispatching of remanufactured-item orders in batches) and inventory-related cost (associated with used-item inventory holding costs and remanufactured-item order waiting costs). We propose five batching policies inspired by shipment consolidation practice (three periodic policies and two threshold policies). For the purpose of computing policy parameters, we develop analytical models that are aimed at minimizing the long-run average expected total cost of the remanufacturer. Since the underlying cost expressions are not analytically tractable, we propose easily computable approximations that lead to closed-form expressions for obtaining policy parameters. A careful numerical investigation demonstrates that the resulting policy parameters are highly effective approximations. Then, we extend the policies by considering disposal options when needed. For this extension, an effective parameter-based approximation approach is developed for computational purposes, and additional numerical experiments demonstrate the effectiveness of the proposed approach.

摘要

本文研究了在按订单生产的再制造环境中出现的基本批量问题。问题设置的特点是随机旧物品退货过程以及再制造商面临的随机再制造物品需求过程。我们明确考虑了所有相关成本，包括固定成本（与二手物品再制造和分批再制造物品订单相关）和库存相关成本（与二手物品库存持有成本和再制造物品相关）订单等待成本）。我们提出了五种受装运合并实践启发的批处理策略（三个定期策略和两个阈值策略）。为了计算策略参数，我们开发的分析模型旨在最小化再制造商的长期平均预期总成本。由于潜在的成本表达式在分析上难以处理，因此我们提出了易于计算的近似值，这些近似值导致用于获取策略参数的封闭式表达式。仔细的数值研究表明，由此产生的策略参数是非常有效的近似值。然后，我们通过在需要时考虑处置选项来扩展政策。对于这种扩展，开发了一种有效的基于参数的近似方法用于计算目的，并且额外的数值实验证明了所提出方法的有效性。我们提出了易于计算的近似值，这些近似值导致用于获取策略参数的封闭式表达式。仔细的数值研究表明，由此产生的策略参数是非常有效的近似值。然后，我们通过在需要时考虑处置选项来扩展政策。对于这种扩展，开发了一种有效的基于参数的近似方法用于计算目的，并且额外的数值实验证明了所提出方法的有效性。我们提出了易于计算的近似值，这些近似值导致用于获取策略参数的封闭式表达式。仔细的数值研究表明，由此产生的策略参数是非常有效的近似值。然后，我们通过在需要时考虑处置选项来扩展政策。对于这种扩展，开发了一种有效的基于参数的近似方法用于计算目的，并且额外的数值实验证明了所提出方法的有效性。