Relief aid stocking decisions under bilateral agency cooperation

We aim to quantify the benefits of cooperation between humanitarian relief agencies in terms of stocking decisions. We consider two agencies that stock the same type of relief item at different locations prone to individual disaster risks and agree to transship the shortage amount from available stocks in case of a disaster. We incorporate the disaster risk to the Newsvendor model by conditioning the stock quantity decisions on the event that a major disaster occurs within the lifetime of the stocked relief item. We optimize the stock quantity for each agency in response to the other's quantity and compute a Nash Equilibrium solution numerically. We apply this game theoretic approach to the case of earthquake preparedness in Istanbul to optimize the stocking decisions of an agency for shelter units in cooperation with another agency. We investigate the characteristics of the solutions under various parameter settings and identify cases in which cooperation may be beneficial to one or both of the agencies.     

烟草商业企业数字仓库的基本流程与系统功能设计研究

数字仓库的应用将协助企业保证供应、压缩库存、提高货物周转效率、节约成本。本文介绍了数字仓库的概念,研究了烟草商业企业数字仓库的基本流程与系统功能结构与设计,并对数字仓库的效益进行了评价。对这些问题的深入研究将有利于提高烟草商业企业的物流水平和服务效率。     

The impact of RFID adoption on donor subsidy through for-profit and not-for-profit newsvendor: Implications for Indian Public Distribution system

Subsidy programs are sponsored by government and international agencies to improve affordability and accessibility of food and health products for socially deprived community. Although the donors in such programs allocate substantial resources to fund subsidies, a lot of it is wasted due to the inefficiency in the system arising out of product shrinkage and misplacement. This study analyzes the impact of private participation and advanced technology like RFID adoption on the donor subsidy under target consumption level. We formulate the problem as a donor funding the subsidy program through for-profit/not-for-profit newsvendor and compare the equivalent subsidy per consumption with and without RFID. We perform numerical analysis, collecting data from the public distribution system of India, and the results indicate that, unless the for-profit firm operates under a substantially reduced level of shrinkage and misplacement, the donor should always prefer a not-for-profit firm for program implementation. We also observe that among all the scenarios, a not-for-profit firm with advanced technology like RFID requires minimum donor subsidy to generate the target expected consumption.     

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.     

Managing inventory with two suppliers under yield uncertainty and risk aversion

In this paper, we consider a single-product single-period inventory model in which the retailer can source from two suppliers. The primary supplier is cheaper but unreliable in the sense that it generates supply yield uncertainty, whereas the secondary supplier is perfectly reliable but more expensive. The reliable supplier's capacity is fixed and the retailer cannot order more than the quantity reserved in advance. We study the problem in the context of a risk-averse retailer who has to determine the optimal order quantity from the primary supplier and the optimal reserved quantity from the secondary supplier. We develop the model in the perspective of a low risk averse retailer and quantify the risk via an exponential utility function. We show by numerical experiments how the resulting dual sourcing strategies differ from those obtained in the risk-neutral analysis. We also examine the sensitivity of some model-parameters on the optimal decisions.     

An inventory reservation problem with nesting and fill rate-based performance measures

In many inventory settings companies wish to provide customer-differentiated service levels. These may, for example, be motivated by differences in the perceived customer lifetime value or by specific contractual agreements. One approach to provide differentiated service levels is to reserve some portion of the available inventory exclusively for specific customer classes. Existing approaches to inventory reservation are typically based on the assumption that a company can assign a customer specific revenue or penalty cost to any order or unit of demand filled or unfulfilled. In practice, however, it is usually extremely difficult to accurately estimate (especially long term) monetary implications of meeting or not meeting customer demand and corresponding service level requirements. The research presented in this paper addresses the problem of setting appropriate inventory reservations for different customer classes based on fill rate-based performance measures. We model a single period inventory reservation problem with two customer classes and nesting. We develop exact expressions for two conflicting performance measures: (1) the expected fill rate of high priority customers and (2) the expected loss in the system fill rate induced by inventory reservation. With these expressions a decision maker can analyze the tradeoff between the loss in overall system performance and the higher expected fill rates for prioritized customers. We provide analytical insights into the effects of nesting and the impact of relevant problem parameters on these two performance measures. The analytical insights are illustrated and highlighted through a set of numerical examples. Although we limit our analysis to a single period inventory reservation problem, we expect that our results can be utilized in a wide range of problem settings in which a decision maker has to ration a perishable resource among different classes of customers.     

An inventory control model with consideration of remanufacturing and product life cycle

This paper investigates inventory control policies in a manufacturing/remanufacturing system during the product life cycle, which consists of four phases: introduction, growth, maturity, and decline. Both demand rate and return rate of products are random variables with normal distribution; the mean of the distribution varies according to the time in the product life cycle. Closed-form formulas of optimal production lot size, reorder point, and safety stock in each phase of the product life cycle are derived. A numerical example is presented with sensitivity analysis. The result shows that different inventory control policies should be adopted in different phases of the product life cycle. It is also found that the optimal production lot size and reorder point are not sensitive to the phase length and the demand changing rate.     

Games with incomplete information: A simplified exposition with inventory management applications

In most existing literature in supply chain management it is assumed that the players possess complete information about the game, i.e., the players' payoff (objective) functions are assumed to be common knowledge. For static and dynamic games with complete information, the Nash equilibrium and subgame perfect equilibrium are the standard solution concepts, respectively. For static and dynamic games with incomplete information, the Bayesian Nash equilibrium and perfect Bayesian equilibrium, respectively, are used as solution concepts. After presenting a brief review of the static and dynamic games under complete information, the application of these two games in inventory management is illustrated by using a single-period stochastic inventory problem with two competing newsvendors. Next, we illustrate the Bayesian Nash and perfect Bayesian equilibrium solution concepts for the static and dynamic games under incomplete information with two competing newsvendors. The expository nature of our paper may help researchers in inventory/supply chain management gain easy access to the complicated notions related to the games played under incomplete information.     

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.     

Reformulation and assessment of the inventory approach to urban growth boundaries

Based on the theoretical framework, in this article we demonstrate how Decision Network can be used to formulate the inventory approach to urban growth boundaries (UGBs) as an application of the planning tool to a general case. In particular, in the inventory approach expansions of UGBs are considered as decision situations, land consumptions as problems, and order sizes of UGBs as solutions. We compare the time- and event-driven systems of the inventory control problem based on the decision network framework. The former in the framework is considered as making single, independent decisions in time, whereas the latter as making multiple, linked decisions in time. Our numerical example shows that the event-driven system is more effective than the time-driven system in that the former incurs less total cost than the former in the UGBs context. The implication is that making multiple, linked decisions, as manifested by Decision Network, would yield more benefits, such as lowering the total cost, to the planner than making these decisions independently.