Age-based policy for blood transshipment during blood shortage

This paper introduces the properties of inventory structure for both rescue and affected banks during blood shortage. An age-based transshipment model is developed, with two preference selection methods for transshipping blood units being presented. Compared to quantity-based policy, the age-based policy under first-in-first-transship is recommended as it can reduce the expired rate more efficiently. Under simulation operating scenarios with time-varying demand and supply, we analyzed the sensitivity of parameters, which include expected supply period, shelf life and blood shortage period. Additionally, this study reveals that the transshipment decision will increase the expired ratio and the overstock ratio after blood shortage.     

Fulfillment source allocation,inventory transshipment,and customer order transfer in e-tailing

We consider an inventory fulfillment-allocation and transshipment problem in an e-tailing environment. For a typical e-tailer, each customer demand is fulfilled from the closest fulfillment center if there are enough inventories. Otherwise, the e-tailer would transship stock from a nearby facility or transfer the customer order so it is fulfilled from another facility, depending on the economics of transportation. We develop a mixed-integer programming model to help e-tailers optimally fulfill customer orders while minimizing logistics costs. We propose a Benders decomposition-based approach to efficiently find optimal solutions. Our computational results demonstrate the importance of considering inventory transshipments in online deliveries.     

Assessment of stock size to minimize cutting stock production costs

A method for assessing the optimal stock size for the expected order size for a single-period one-dimensional cutting stock problem is proposed. The stock size is optimal when the expected total costs of trim loss, warehousing, and non-fulfilment are minimum. The stock size is the sum of all bar lengths in the stock, and the order size is the sum of shorter bar lengths in various numbers of pieces. Using simulated test cases, a statistical estimation of optimal stock size is conducted, which in our case is approximately 50% above the expected order. The proposed method can help company choose the appropriate level of stock to minimize their total costs.     

Production planning and inventories optimization: A backward approach in the convex storage cost case

We study the deterministic optimization problem of a profit-maximizing firm which plans its sales/production schedule. The firm controls both its production and sales rates and knows the revenue associated to a given level of sales, as well as its production and storage costs. The revenue and the production cost are assumed to be respectively concave and convex. In Chazal et al. [Chazal, M., Jouini, E., Tahraoui, R., 2003. Production planning and inventories optimization with a general storage cost function. Nonlinear Analysis 54, 1365–1395], we provide an existence result and derive some necessary conditions of optimality. Here, we further assume that the storage cost is convex. This allows us to relate the optimal planning problem to the study of a backward integro-differential equation, from which we obtain an explicit construction of the optimal plan.     

民营书业图书高库存原因探析

针对掣肘我国民营书业健康发展的图书高库存问题，从市场的供求矛盾、图书的商品特性、行业的发行方式、民营书业自身的行业特殊性、发行渠道的上下游信息壁垒、采购的盲目多样性、库存管理和控制的落后、物流效率的低下等方面分析其原因，从而为下一步探寻有效的解决方案，促使民营书业乃至整个图书业的健康发展提供帮助。     

INTERORGANIZATIONAL TIME‐BASED POSTPONEMENT IN THE SUPPLY CHAIN

This paper presents the results of empirical research on the use of time‐based postponement in a supply chain context using data collected from two manufacturers, a distributor, and a retailer. The analysis shows that implementing postponement at the firm level can result in the supply chain carrying more inventory. In order to achieve its full potential, postponement needs to be implemented across organizations in the supply chain.     

The role of e-tailer inventory policy on e-tailer pricing and profitability

This study explores the impact of the e-tailer's inventory policy on its pricing strategy and profitability via a two-period model. Specifically, we identify two inventory policies: zero inventory and positive inventory. The findings show that the zero-inventory e-tailer charges lower prices than the positive-inventory one, but the price differential decreases over time if the market expands rapidly. The findings also show that the zero-inventory policy is preferred under a moderately positive relationship between reservation price and impatience for delivery, whereas the positive-inventory policy is preferred when these two variables are independent of each other. Furthermore, the results show that a more rapid expansion of market is a favorable condition for the zero-inventory e-tailer. The authors also discuss the implications of the inventory policy for an e-tailer's performance.     

资本永续盘存法及其国内应用

资本存量数据是宏观经济运行政策研究的重要决定因素。资本存量核算比较复杂，在理论与技术两个层面都存在诸多问题难以厘清。我国资本统计十分薄弱，数据可得性成为资本存量估算的严重制约。在我国经济增长研究中，如何准确估算资本存量一直是困扰研究者的难题。学术界需要使用这方面数据，又促使很多学者基于各自的研究目的对我国资本存量进行估算。这些研究分别利用不同的假设和处理方法，这使我国资本存量数据出现了差异很大的众多版本。本文在对资本存量估算方法进行梳理之后，对我国资本估算现有研究进行了回顾和评论。     

On the relationship between cost and service models for general inventory systems

In this paper, we present a systematic overview of possible relations between cost and service models for fairly general single- and multi-stage inventory systems. In particular, we relate various types of penalty costs in pure cost models to equivalent types of service measures in service models. We show how an optimal policy for a service model may be obtained from cost-optimal policies in a related pure cost model. Pure cost models have been studied extensively in the literature. By our results it seems possible to transform many of the known optimal solutions for pure cost models to service models, which are more appropriate from a practical point of view. A number of examples are discussed to show the generality and the possibly far reaching consequences of the results.     

Inventory inaccuracies in the wholesale supply chain

The inventory level shown in the Information System contrary to popular belief and assumptions in most academic papers and in spite of the considerable amounts invested in information technology, is often inaccurate. The inventory inaccuracy occurs when the inventory shown in the Information System is not in agreement with the actually available inventory. In this paper, we first describe the major factors generating inventory inaccuracy. Then, we provide situations permitting to manage an inventory system subject to errors. We provide a general framework permitting to model the inventory inaccuracy issue. In particular, we link the inaccuracy issue with the well known random yield problem. The shown link permits us to derive the optimal ordering policy of an inventory framework where demand satisfaction is done based on the inventory records (which are subject to inaccuracies). We also propose an analysis permitting to show the added value of an advanced identification system such as the RFID technology.