VMI模式下供应商之间的生产进度信息共享研究

当制造商采用供应商管理库存策略时,供应商之间的生产进度信息共享一般能减少供应商的缺货和存货持有成本。针对供应商的生产提前期的不同情况,建立了供应商库存成本的优化模型。分析了供应商之间的生产提前期变动大小比较对供应商生产进度信息共享选择的影响,指出在绝大多数情形下生产进度信息共享是有利的,但在某些情形下共享不一定有利。无论信息共享与否,供应商中某一方存在的生产提前期的不确定都会增加供应商的最小期望成本,并对供应商如何实现期望成本最小提出了建议。     

供应商管理库存下基于消费者行为偏好的全渠道运营策略

在供应商管理库存背景下,研究了消费者线上参考效应、线下库存效应以及渠道偏好对供应链成员运营策略的影响。利用微分博弈和连续型动态规划理论获得了独立运营、基于供应商服务成本分担契约的部分合作运营以及协同运营三种模式下的成员策略及绩效。由比较静态分析和对比分析发现：库存效应对生产量具正向影响,对产品质量、大数据营销服务和线下服务具负向影响;消费者不同条件下的线上偏好对企业决策有不同的影响;供应商服务成本分担契约能激励零售商提升线下产品服务,一定程度上改进企业独立运营的绩效水平。为进一步协调分散式供应链,在上述契约基础上设计了供应商收益分享及双边成本分担契约。数值算例发现：新契约在一定条件下可实现分散式供应链的完美协调;消费者参考质量过度依赖品牌商誉易产生"锚定心理",不仅会抑制成员生产和服务积极性,造成库存积压,阻碍品牌商誉积累,损害企业利润,也不利于消费者获得更好的购物体验。     

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.     

Managing Slow‐Moving Perishables in the Grocery Industry

We address the value of information and value of centralized control in the context of a two‐echelon, serial supply chain with one retailer and one supplier that provide a single perishable product to consumers. Our analysis is relevant for managing slow‐moving perishable products with fixed lot sizes and expiration dates of a week or less. We evaluate two supply chain structures. In the first structure, referred to as decentralized information sharing, the retailer shares its demand, inventory, and ordering policy with the supplier, yet both facilities make their own profit‐maximizing replenishment decisions. In the second structure, centralized control, incentives are aligned and the replenishment decisions are coordinated. The latter supply chain structure corresponds to the industry practices of company‐owned stores or vendor‐managed inventory. We measure the value of information and value of centralized control as the marginal improvement in expected profits that a supply chain achieves relative to the case when no information is shared and decision making is decentralized. Key assumptions of our model include stochastic demand, lost sales, and fixed order quantities. We establish the importance of information sharing and centralized control in the supply chain and identify conditions under which benefits are realized. As opposed to previous work on the value of information, the major benefit in our setting is driven by the supplier's ability to provide the retailer with fresher product. By isolating the benefit by firm, we show that sharing information is not always Pareto‐improving for both supply chain partners in the decentralized setting.     

Inventory Management in China: An Empirical Study

With the outsourcing of manufacturing activities from Western countries, China has gradually become the global manufacturing hub. In the presence of increased competition from both inside and outside of China, many Chinese manufacturers have turned to scientific management approaches and implemented various enterprise systems. In academia, there has been a growing interest in quantifying the impacts of such efforts on the corporate performance of Chinese firms, and research has been carried out in areas such as finance and accounting. However, due to limited visibility of operational decisions and data, there seems to be a lack of investigation into the impacts on the firms’ operational performance in the literature. In this article, we apply an empirical method to investigate the inventories of 1286 firms listed on the two stock exchanges in China, the Shanghai Stock Exchange and the Shenzhen Stock Exchange. We find that on average the inventory levels have declined over time and that the firm‐level data is consistent with several implications derived from classical inventory models.     

Clickstream Data and Inventory Management: Model and Empirical Analysis

We consider firms that feature their products on the Internet but take orders offline. Click and order data are disjoint on such non‐transactional websites, and their matching is error‐prone. Yet, their time separation may allow the firm to react and improve its tactical planning. We introduce a dynamic decision support model that augments the classic inventory planning model with additional clickstream state variables. Using a novel data set of matched online clickstream and offline purchasing data, we identify statistically significant clickstream variables and empirically investigate the value of clickstream tracking on non‐transactional websites to improve inventory management. We show that the noisy clickstream data is statistically significant to predict the propensity, amount, and timing of offline orders. A counterfactual analysis shows that using the demand information extracted from the clickstream data can reduce the inventory holding and backordering cost by 3% to 5% in our data set.     

Inventory Sharing with Transshipment: Impacts of Demand Distribution Shapes and Setup Costs

We study a firm's optimal transshipment problem considering the impacts of setup costs for transshipment and demand distribution shapes. We assume that the demand follows a three‐point distribution, which changes from a degenerate distribution, to a unimodal distribution, and to a bimodal distribution as the demand shape parameter increases. We find that as the demand shape parameter increases, the optimal transshipment strategy changes from no transshipment to transshipment, and finally to no transshipment. The firm would use two‐way transshipment when the shape parameter is relatively small, while it would use one‐way transshipment when the shape parameter is relatively large. When the optimal strategy is one‐way transshipment, the transshipment direction depends on the contribution margin as well as the demand shape, when the difference between the two demand uncertainties is small. Our study of a dual‐channel retail system shows that the additional benefit of two‐way transshipment is negligible when there are many retail stores.     

A Bayesian Inventory Model Using Real‐Time Condition Monitoring Information

Lack of coordination between machinery fault diagnosis and inventory management for spare parts can lead to increased inventory costs and disruptions in production activity. We develop a framework for incorporating real‐time condition monitoring information into inventory decisions for spare parts. We consider a manufacturer who periodically replenishes inventory for a machine part that is subject to deterioration. The deterioration is captured via condition monitoring and modeled using a Wiener process. The resulting degradation model is used to derive the life distribution of a functioning part and to estimate the demand distribution for spare parts. This estimation is periodically updated, in a Bayesian manner, as additional information on part deterioration is obtained. We develop an inventory model that incorporates this updated demand distribution and demonstrate that a dynamic base‐stock policy, in which the optimal base‐stock level is a function of some subset of the observed condition monitoring information, is optimal. We propose a myopic critical fractile policy that captures the essence of the optimal policy, but is easier to compute. Computational experiments indicate that this heuristic performs quite well relative to the optimal policy. Adaptive inventory policies such as these can help manufacturers to increase machine availability and reduce inventory costs.     

一类供应商管理库存供应链协调策略研究

对有确定需求、有初始库存和库存短缺的一种畅销商品,建立了供应商管理库存的供应链模型.然后,分别分析分散式、集中式和VMI三种供应链模式下的库存补充数量最优解及各方收益情况,得到VMI的实施将可能造成供应商收益下降.再运用委托-代理理论分别讨论了信息对称和信息不对称时的VMI数量折扣契约设计问题.最后,给出算例说明了,此协调策略有助于VMI的实施.     

The Effects of Competitive Environment on Supply Chain Information Sharing and Performance: An Empirical Study in China

Information sharing in supply chains has become an important topic over the past decade. This study uses data from 617 Chinese manufacturing firms to investigate the relationships among competitive environments, supply chain information sharing (SCIS), and supply chain performance. The results of structural equation modeling analysis show that (i) international competition is positively related to all three types of SCIS whereas local competition is not significantly related to any of the three types, (ii) internal information sharing is positively related to external information sharing with suppliers and customers, and (iii) internal information sharing and information sharing with customers are positively related to superior supply chain performance, whereas supplier information sharing is not significantly related to performance. The findings enhance our understanding of the relationships among competitive environment, SCIS, and supply chain performance in Chinese manufacturing settings.     

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.     

供应链成员信息共享技术策略博弈分析

运用博弈论分析不确定条件下供应链成员的信息共享技术策略。首先建立基于需求不确定和供应不确定两种参数的"供应商+零售商"的期望收益模型,证实在不确定条件下的存在双方期望收益的最优解;建立三阶段博弈模型,探讨双方信息共享技术策略的博弈关系;分析四种的均衡状态:探讨初始需求不确定性、供应商的信息推测能力与零售商收益的不同关系对双方信息共享技术策略的影响,结论显示:当初始需求不确定性较大时,零售商以拒绝策略为先,进一步的策略取决于供应商的信息推测能力及其对零售商收益的影响,如果该能力较强,零售商将采取接受策略,反之则反。     

Customer‐Base Concentration and Inventory Efficiencies: Evidence from the Manufacturing Sector

What is the link between customer‐base concentration and inventory efficiencies in the manufacturing sector? Using hand‐collected data from 10‐K Filings, we find that manufacturers with more concentrated customer bases hold fewer inventories for less time and are less likely to end up with excess inventories, as indicated by the lower likelihood and magnitude of inventory write‐downs and reversals. Using disaggregated inventory disclosures, we find that inventory efficiencies primarily flow through the finished goods inventory account, while raw material efficiencies are offset by higher work‐in‐process holdings and longer work‐in‐process cycles. In additional analysis, we document a valuation premium for more concentrated manufacturers after controlling for other firm characteristics, including default risk and cost of capital estimates. We conclude that investors trade off the costs and benefits of relationships with a limited number of major customers and, on balance, consider customer‐base concentration as a net positive for firm valuation. Overall, our study adds to interdisciplinary research in accounting and operations management by shedding new light on the relevance of major customer disclosures for fundamental analysis and valuation in the manufacturing sector.     

End‐of‐Life Inventory Problem with Phaseout Returns

We consider the service parts end‐of‐life inventory problem of a capital goods manufacturer in the final phase of its life cycle. The final phase starts as soon as the production of parts terminates and continues until the last service contract expires. Final order quantities are considered a popular tactic to sustain service fulfillment obligations and to mitigate the effect of obsolescence. In addition to the final order quantity, other sources to obtain serviceable parts are repairing returned defective items and retrieving parts from phaseout returns. Phaseout returns happen when a customer replaces an old system platform with a next‐generation one and returns the old product to the original equipment manufacturer (OEM). These returns can well serve the demand for service parts of other customers still using the old generation of the product. In this study, we study the decision‐making complications as well as cost‐saving opportunities stemming from phaseout occurrence. We use a finite‐horizon Markov decision process to characterize the structure of the optimal inventory control policy. We show that the optimal policy consists of a time‐varying threshold level for item repair. Furthermore, we study the value of phaseout information by extending the results to cases with an uncertain phaseout quantity or an uncertain schedule. Numerical analysis sheds light on the advantages of the optimal policy compared to some heuristic policies.     

Joint Inventory and Pricing Coordination with Incomplete Demand Information

In retailing operations, retailers face the challenge of incomplete demand information. We develop a new concept named K‐approximate convexity, which is shown to be a generalization of K‐convexity, to address this challenge. This idea is applied to obtain a base‐stock list‐price policy for the joint inventory and pricing control problem with incomplete demand information and even non‐concave revenue function. A worst‐case performance bound of the policy is established. In a numerical study where demand is driven from real sales data, we find that the average gap between the profits of our proposed policy and the optimal policy is 0.27%, and the maximum gap is 4.6%.     

企业内员工知识共享的实证研究

将知识特性以及员工知识共享的意愿作为分析影响员工知识共享的2个因素,以此建立一个概念框架;运用结构方程模型方法,结合对115家中国企业所作的调查研究数据,从实证的角度研究这些因素对企业内部员工知识共享的影响.研究结果表明,知识的隐含性和分散性与企业员工知识共享之间存在显著负相关关系,员工对未来合作的预期、知识的价值与企业员工知识共享之间存在显著正相关的关系.最后,讨论了研究结果的管理含义及进一步研究方向.     

Multi‐Echelon Inventory Management under Short‐Term Take‐or‐Pay Contracts

We extend the Clark–Scarf serial multi‐echelon inventory model to include procuring production inputs under short‐term take‐or‐pay contracts at one or more stages. In each period, each such stage has the option to order/process at two different cost rates; the cheaper rate applies to units up to the contract quantity selected in the previous period. We prove that in each period and at each such stage, there are three base‐stock levels that characterize an optimal policy, two for the inventory policy and one for the contract quantity selection policy. The optimal cost function is additively separable in its state variables, leading to conquering the curse of dimensionality and the opportunity to manage the supply chain using independently acting managers. We develop conditions under which myopic policies are optimal and illustrate the results using numerical examples. We establish and use a generic one‐period result, which generalizes an important such result in the literature. Extensions to cover variants of take‐or‐pay contracts are included. Limitations are discussed.     

Adoption of e‐Processes by Service Firms: An Empirical Study of Antecedents

This paper investigates empirically antecedents of the adoption of web‐based processes (e‐processes) by service providers. We examine whether rational efficiency (expressed by expected performance benefits and access to new markets), the bandwagon effect (expressed by external pressure), and barriers (both internal and customer related) influence Internet use for transactions (e‐transactions) and/or to extend the relationships between service providers and their customers (e‐CRM). The findings, based on a sample of 338 service firms, show that rational efficiency and the bandwagon effect drive both types of e‐processes. Conversely, only internal barriers have a negative impact on adoption of e‐processes, while barriers related to customers do not have a significant impact. These findings have important academic and managerial implications, given the limited evidence regarding the implementation of e‐processes in services.     

在ARIMA(0,1,1)需求下的牛鞭效应与信息共享的评价

本文考虑一个包含一个供应商和一个零售商的两级供应链,研究在需求模型ARIMA(0,1,1)下牛鞭效应的量化和信息共享的价值,比较信息共享之前和之后的差异,其结果表明信息共享能给供应商带来减轻牛鞭效应、减少现有平均库存以及降低成本等好处。     

Inventory Rationing in a Make‐to‐Stock System with Batch Production and Lost Sales

We address an inventory rationing problem in a lost sales make‐to‐stock (MTS) production system with batch ordering and multiple demand classes. Each production order contains a single batch of a fixed lot size and the processing time of each batch is random. Assuming that there is at most one order outstanding at any point in time, we first address the case with the general production time distribution. We show that the optimal order policy is characterized by a reorder point and the optimal rationing policy is characterized by time‐dependent rationing levels. We then approximate the production time distribution with a phase‐type distribution and show that the optimal policy can be characterized by a reorder point and state‐dependent rationing levels. Using the Erlang production time distribution, we generalize the model to a tandem MTS system in which there may be multiple outstanding orders. We introduce a state‐transformation approach to perform the structural analysis and show that both the reorder point and rationing levels are state dependent. We show the monotonicity of the optimal reorder point and rationing levels for the outstanding orders, and generate new theoretical and managerial insights from the research findings.