Pool‐Point Distribution of Zero‐Inventory Products

We study zero‐inventory production‐distribution systems under pool‐point delivery. The zero‐inventory production and distribution paradigm is supported in a variety of industries in which a product cannot be inventoried because of its short shelf life. The advantages of pool‐point (or hub‐and‐spoke) distribution, explored extensively in the literature, include the efficient use of transportation resources and effective day‐to‐day management of operations. The setting of our analysis is as follows: A production facility (plant) with a finite production rate distributes its single product, which cannot be inventoried, to several pool points. Each pool point may require multiple truckloads to satisfy its customers' demand. A third‐party logistics provider then transports the product to individual customers surrounding each pool point. The production rate can be increased up to a certain limit by incurring additional cost. The delivery of the product is done by identical trucks, each having limited capacity and non‐negligible traveling time between the plant and the pool points. Our objective is to coordinate the production and transportation operations so that the total cost of production and distribution is minimized, while respecting the product lifetime and the delivery capacity constraints. This study attempts to develop intuition into zero‐inventory production‐distribution systems under pool‐point delivery by considering several variants of the above setting. These include multiple trucks, a modifiable production rate, and alternative objectives. Using a combination of theoretical analysis and computational experiments, we gain insights into optimizing the total cost of a production‐delivery plan by understanding the trade‐off between production and transportation.     

委托代理理论下应急物资库存成本控制

运用委托代理理论方法研究了政府委托应急物资生产企业管理应急物资库存后,存在道德风险时,政府如何激励企业努力降低应急物资库存成本的问题。首先分析不同情形下政府与企业的库存成本构成,继而假设政府利用招标机制将应急物资的采购和库存管理一体化操作,建立满足企业参与约束及激励相容约束条件的政府期望效用最大化模型。最后用遗传算法进行仿真计算,结合算例分析政府和企业在不同情形下的收益与成本,结果表明实施激励可明显增加政府的期望效用。     

准时生产与库存对轮胎生产成本的影响研究——以卡莱轮胎公司为例

库存管理是企业管理的重要组成部分,现代物流管理技术可以从根本上降低仓储成本,方法之一就是零库存技术。但卡莱轮胎公司自实行零库存管理以来,其生产成本却呈现大幅度上升趋势。要控制好生产成本,并有效获得较大利润,就应从轮胎生产成本构成要素角度出发,适当建立库存,以降低因频繁转化规格而提高的轮胎生产成本。     

基于供应链金融的随机需求条件下的订货策略

本文将供应链金融中的融资问题融入到允许延迟支付的报童模型中,同时考虑了订货商的销售情况对偿还能力的影响,融资利息、销售收入利息以及支付信用期等现金管理要素,建立起订货商在连续随机需求条件下的库存管理模型,通过对模型的求解与灵敏度分析,对供应链金融模式下订货商的订货策略进行了深入探讨,得出了一系列有益的结论。所建立的模型同时为中小销售型企业提供一种新的资金获取以及确定订货策略的方法。     

Contracting Under Vendor Managed Inventory Systems Using Holding Cost Subsidies

Vendor managed inventory systems are becoming increasingly popular. An important issue in implementing a vendor managed inventory scheme is the contracting terms that dictate the ownership of the inventory and the responsibility of inventory replenishment decisions. Thus the performance of a vendor managed system crucially depends on these terms and on how inventory‐related costs are shared in a supply chain. We consider a system where a manufacturer supplies a single product to a retailer who faces random demand in a competitive market. The retailer incurs a fixed cost per order, inventory holding cost, and a penalty cost for a stockout (unsatisfied demand is back‐ordered). Further, the manufacturer incurs a penalty cost when there is a stockout at the retailer and a fixed replenishment cost. We assume that the players are rational and act noncooperatively. We compare the performance of retailer managed inventory systems, where the retailer places orders and makes replenishment decisions, with vendor managed inventory systems, wherein the vendor or manufacturer makes inventory and replenishment decisions. Specifically, in the vendor managed inventory system, we propose and evaluate holding cost subsidy‐type contracts on inventories offered by the retailer to improve system performance. We evaluate this contract in the context of three widely used inventory systems—deterministic economic order quantity, continuous review (Q, r) policies, and periodic review policies—and show when such contracts may improve channel performance.     

Order Progress Information: Improved Dynamic Emergency Ordering Policies

Technologies such as radio‐frequency identification and global positioning systems can provide improved real‐time tracking information for products and replenishment orders along the supply chain. We call this type of visibility order progress information. In this paper, we investigate how order progress information can be used to improve inventory replenishment decisions. To this end, we examine a retailer facing a stochastic lead time for order fulfillment. We characterize a replenishment policy that is based on the classical (Q, R) policy and that allows for releasing emergency orders in response to the order progress information. We show that the optimal structure of this policy is given by a sequence of threshold values dependent on order progress information. In a numerical study we evaluate the cost savings due to this improved replenishment policy.     

Value of Sharing Production Yield Information in a Serial Supply Chain

New developments in corporate information technology such as enterprise resource planning systems have significantly increased the flow of information among members of supply chains. However, the benefits of sharing information can vary depending on the supply chain structure and its operational characteristics. Most of the existing research has studied the impact of sharing downstream information (e.g., a manufacturer sharing information with its suppliers). We evaluate the benefits of sharing upstream yield information (e.g., a supplier sharing information with the manufacturer) in a two‐stage serial supply chain in which the supplier has multiple internal processes and is faced with uncertain output due to yield losses. We are interested in determining when the sharing of the supplier's information is most beneficial to the manufacturer. After proposing an order‐up‐to type heuristic policy, we perform a detailed computational study and observe that this information is most beneficial when the supplier's yield variance is high and when end‐customer demand variance is low. We also find that the manufacturer's backorder‐to‐holding cost ratio has little, if any, impact on the usefulness of information.     

基于EOQ模型的存货质押融资业务模式选择研究

委托监管模式、物流银行模式和统一授信融资模式是存货质押融资的几种主要模式,本文采用EOQ模型研究了这三种融资模式下供应链成员的决策和收益情况,并分析了这三种融资模式中制造商与物流企业参与融资的条件。通过对融资模式进行比较分析,论文指出了融资模式对供应链成员收益的影响。主要研究结论指出,在质押率和融资利率的特定区域内,物流企业和制造商同时愿意参与质押融资。由于在统一授信模式中,银行的日常的运营成本比委托监管模式低,银行获得比委托监管模式更多的利润。在选择融资模式时,银行更偏好于统一授信模式。对于物流企业来说,若统一授信模式中物流企业的沉淀资金收益率大于银行的利率,它的利润要比委托监管模式更多,否则要少于委托监管模式。本文的研究结论为存货质押融资业务的模式选择提供了一些的理论参考。     

通货膨胀下的联合库存选址模型研究

研究了通货膨胀对涉及一个供应商、多个候选配送中心和零售商的三级分销网络设计的影响.不同于传统的联合库存选址模型,所研究的模型考虑了整个系统的相关成本的时间价值,其目标是使在一定的通货膨胀率下总的选址、运输和库存成本之和的现值最小.为此,建立了一个非线性的整数规划模型,该模型为无容量约束问题的扩展模型,属于NP-hard问题.提出了3种基于不同编码形式的遗传算法用于求解该模型,并通过不同规模的算例对3种算法进行了有效性的分析和对比.最后,通过对各算例的计算结果的分析,发现随着通货膨胀率的增长,为了使这个分析网络的总成本现值最小,需要增加建立的DC的数量.     

服务水平约束下的建筑安装行业多仓库联合库存系统模型研究

本文针对建筑安装行业库存管理的特点,对其不同地点的多个仓库的库存方式进行综合分析,建立了服务水平约束下的建筑安装行业多仓库联合库存系统模型,给出了相应的数学模型与算法。通过算例验证表明,服务水平约束下的建筑安装行业多仓库联合库存系统模型可以有效降低建设项目的库存成本,对增加企业利润有着十分重要的现实意义。