随机需求时上游段VMI模式共赢条件

考虑实施上游段VMI模式后,订货（配送）主动权的转移导致订货（配送）策略的不同,以及制造商对各零部件需求速率的不同导致其对各零部件的订货周期也不一致的情况。假设外界需求随机,通过建立模型,结合模拟仿真,对实施上游段VMI模式前后各企业的经济效益进行比较,探讨实施VMI且制造商销售价格不变时,供应商是否存在合理的销售价格涨幅区间。该区间的价格既能弥补供应商因管理制造商零部件库存多消耗的成本,也能使制造商和供应商的经济效益都有所提高,实现共赢,为上游段VMI模式的推广提供理论依据。     

供应链上游层面VMI模式的利益分配机制

选取供应链上游层面VMI模式为研究对象,考虑实施VMI后,订货主动权的转移导致订货策略的变化,以及制造商对各零部件需求速率的不同导致其对各零部件的订货周期也不一致的情况,通过建立经济效果模型,探讨上游层面VMI对供应链整体利益的影响.在此基础上,根据供应商与制造商在合作中经常出现的3种情境——平等、供应商占优、制造商占优,建立VM1模式下不同情境的利益分配机制.该机制最终可体现在供应商所售产品的重新定价上,此定价既能弥补供应商因管理制造商库存而增加的成本,又可使制造商的利润得到保障,达到共赢的目的,为上游层面VMI模式的顺利推广提供理论依据.     

确定需求时上游层面VMI利益分配机制研究

假设外界需求确定,充分考虑实施VMI后,订货主动权的转移导致订货策略的变化,以及制造商对各零部件需求速率的不同导致订货周期也不一致的现象,建立供需方在传统库存模式与VMI模式下的经济效果模型,得出VMI可使供应链上游层面整体受益的结论。在此基础上,区分供应商与制造商在合作中经常出现的3种情境——平等、供应商占优、制造商占优,利用Stackelberg博弈、纳什均衡等理论,构建上游层面VMI模式下各情境的利益分配机制,该机制最终体现在供应商所售产品的重新定价上,此定价既能弥补供应商因管理制造商库存而增加的成本,又可使制造商的利润得到保障,达到共赢的目标,同时,还可为如何在价格层面制定激励策略提供理论参考。     

三级供应链VMI收益及Shapley值分配仿真研究

考虑需求放大、订货及库存成本变动等因素,构建三级供应链在分散式、上游段、下游段及集成式VMI四种情况下的收益模型,通过仿真定量说明VMI对于上、下游企业收益及风险的不同影响,并得出结论:下游段VMI实施后,集成式VMI将成为激励相容,而上游段VMI的实施将阻碍集成式VMI的实现,证实了VMI的实施顺序对供应链管理的重要影响。后采用Shapley值法分析各企业特征函数,确定Shapley值计算公式,进行收益分配,解决了收益与风险不对等所导致的VMI合作不稳定问题,促进集成式VMI的形成与长期稳定。     

分散式VMI与Supply Hub协同供应链对比研究

考虑物流能力约束条件下,分别构建了供应商与Hub运营商、供应商与分散式VMI仓库分散决策的配送间隔及成本决策模型。研究表明,Supply Hub模式能够以更短的配送间隔和更低的运作成本满足JIT制造商的生产需要,并且参与的供应商数目越多,Supply Hub的优势就越明显。最后,通过算例进一步验证了Supply Hub模式在配送间隔和运作成本上存在的优势,并模拟了各参数对其运作优势的影响。     

基于Shapley值法的供应链上游段VMI的利益分配机制

实施VMI后如何分配利益直接关系到各参与者的积极性及VMI的实施效果,学术界长期立足于供应链下游段对此问题进行探讨.选取上游段VMI为研究对象,考虑实施VMI前后供应链参数的变化情况,建立经济效果模型,基于利益分享契约视角,利用Shapley值法构建上游段VMI的利益分配机制,并进行算例分析.结果表明:该机制使得由于实施上游段VMI而产生的利益在各参与者之间合理的分配,解决了供应商由于承担过多库存成本而利益受损的问题,实现了共赢.在实际操作中,该机制可通过各参与者在实施上游段VMI前共同制定利益分享契约而实现.     

产能与需求不确定下基于MOI和VMI的供应链比较研究

为分析供应链运作机制对降低产能不确定和需求不确定的影响,对比研究了MOI和VMI两种供应链运作模式下单关键零部件供应商-单制造商组成的两级供应链系统。MOI模式下,制造商负责产品的库存决策,并承担相应的零部件库存成本和缺货成本;VMI模式下,供应商负责产品的库存决策和额外产能储备决策,并承担相应的零部件库存成本和过剩能力闲置成本。给出了供应链的最优解及期望利润;为进一步讨论供应链管理模式对提升供应链运作效率的管理意义,分析了随机需求、随机产能及批发价格对两种模式的影响。     

VMI进行卡尔多-希克斯改进必要性研究

考虑需求放大、订货及库存成本变动等因素,构建完全竞争市场条件下的VMI模型,进行解析分析和仿真求解,证实了供应商管理库存策略进行卡尔多-希克斯改进的必要性。运用灵敏度分析,确定了影响上游企业参与VMI的重要因素,并得出越是优秀的上游企业参与VMI的积极性反而较低的结论。     

基于VMI的供应链协调模型应用研究

以一个制造商和一个供应商构成的多产品、多阶段供应链为背景,使用多目标规划的方法构造了生产原料平衡、制造商利润和供应商利润等目标函数及其约束条件,建立了供应商管理制造商生产原料库存的供应链协调模型.为验证模型的有效性和可行性,设计了一个应用算例.算例的分析表明:基于VMI的供应链协调模型能够保证各阶段供应商的交付量等于制造商的订购量,使制造商的利润提高,但供应商因实施VMI利润降低了.最后,通过对产品市场价格、原材料价格、生产能力、市场容量等参数的灵敏度分析,找出了供应链各参量的变化规律.     

紧急订单成本信息不对称下的激励契约设计

在正常订单和紧急订单供应商共存情况下.分析制造商的最优订货策略.正常订单供应商采购提前期较长.需在销售期前进行订货.紧急订单供应商交货期较灵活.但交货期长短与成本相关且该成本信息为其私有信息.考虑在此条件下制造商的订货策略(与正常订单供应商)和激励合同设定问题(与紧急订单供应商).最后,比较了紧急订单供应商的存在与否对制造商的订货以及利润的影响.     

基于讨价还价博弈的ATO供应链零部件生产及补货策略

通过建立ATO供应链中最终产品制造商与其两个供应商间的讨价还价合作模型,研究了ATO供应链的零部件生产补货策略和相应的利润分配策略,并探讨了供应链中各合作主体议价能力对最优解的影响。研究发现,ATO供应链应随着最终产品销售价格的提高而增加零部件产量,随最终产品组装成本或零部件生产成本的提高而减少零部件产量;随着最终产品制造商对其中一个供应商议价能力的增强,该供应商零部件的转移价格及其利润会降低,而另外一个供应商的零部件转移价格和利润会提高;若最终产品制造商比另外一个供应商的议价能力强,其期望利润会得到提高,反之,则会降低。     

The role of spot market in a decentralised supply chain under random yield

We consider a decentralised supply chain with demand uncertainty, wherein a manufacturer sells a single product that consists of two components to the end consumer through an independent distributor. Assume that one component has a random yield, the manufacturer may rely on the spot market to replenish any shortage components after the random yield is realised. We identify the optimal product order, component production and replenishment decisions under two different situations. One is the traditional arrangement that the distributor decides the product procurement quantity and the manufacturer chooses the production quantity. The other is vendor-managed inventory (VMI) arrangement in which the manufacturer is responsible for both the order and the production decisions. The results show that the role of spot market can effectively offset the negative effects from production yield’s, market demand’s and component spot price’s variances. Consequently, the spot market leads to the cooperation between the manufacturer and the distributor, and improves the channel’s overall performance, in particular under the VMI arrangement when the wholesale price is sufficiently high.     

Configuring a manufacturing firm's supply network with multiple suppliers

Consider a supply network consisting of a manufacturer and its suppliers. The manufacturer produces different types of products, using a common set of inputs (e.g., raw materials and/or component parts) from the suppliers: but, each product needs a different mix of these inputs. The manufacturer sells its finished products to the market at the end of the current decision horizon, facing an uncertain market demand. In situations where a manufacturer has outsourced its parts production to contract manufacturers, the contract manufacturer's capacity available for the given manufacturer in a particular time period may be limited by “capacity reservation” agreements made in advance. Thus, in making production mix decisions for the current planning horizon, the manufacturer has to take into account both its own and the component suppliers' capacity restrictions. We develop a mathematical model and an iterative algorithm that helps the manufacturer solve its supply configuration problem, that is, how much of each raw material and/or component part to order from which supplier, given capacity limits of suppliers as well as the manufacturer. The model takes into account such factors as market demand uncertainty, costs and product characteristics. We present an numerical example to illustrate the interacting effects among critical parameters in the model, and apply the model to a real-world case of a computer manufacturer.     

基于VMI的医院供应管理

医院大部分药品及相关用品属于易逝品,针对该类产品的特点,将VMI(Vender Managed Inventory)方法引入到医院供应管理研究中,通过建立两级供应链库存定量模型(即供应商-医院关系模型),比较实施VMI方法前后,医院、供应商以及供应链总库存成本的变化情况.通过定量比较证实,实施VMI方法可以有效降低医院及供应链总库存成本,供应商的库存成本虽有所升高,但是可以通过转移支付方法,使供应商与医院达到利益均衡点,从而降低供应链总库存成本,获得pareto均衡.     

Design of traceability systems for product recall

A product recall is very expensive and a poorly executed recall can be devastating to a company’s reputation. It is, therefore, important to improve the traceability for supply chains to address potential recalls. This paper studies the recall dynamics in a two-stage supply chain with a manufacturer and two suppliers. It is shown that the suppliers would opt-out in improving traceability due to misalignment of incentives, leading to diminishing traceability of the whole supply chain and high product recall liabilities for the manufacturer. To address this problem, this research designs an interest-sharing mechanism by which the recall liability reduction of the manufacturer due to improved traceability can be shared with the suppliers to induce traceability improvement effort. Results show that the interest-sharing mechanism improves not only the economic benefit, but also the traceability for each party. We also provide a systematic framework to choose the design parameters, including the degree of accuracy and level of coding, for the supply chain to realise such benefits.     

Horizontal cooperation and information sharing between suppliers in the manufacturer–supplier triad

In this paper, we analyse a collusion and information-sharing problem between two suppliers in a manufacturer–supplier triad. The manufacturer treats one supplier as a strategic supplier and the other as a backup. While the strategic supplier offers modules of good quality but longer lead times, the backup supplier offers modules with inferior quality but shorter lead times. If there are urgent orders, the manufacturer must turn to the backup supplier. However, it is difficult for the manufacturer to estimate whether the urgent supplier has put extra effort into their production. We formulate this problem by assuming that the urgent supplier has either low or high production costs. To take advantage of the competition between two suppliers, the manufacturer can design a contract menu that defines total payment and lead times, under which both suppliers may be worse off. Meanwhile, it is possible for the suppliers to tacitly form a coalition, and to even share the private cost information. We study this problem by formulating it as a three-stage game. Furthermore, we investigate the variation of profits for each part of the supply chain. We find that the manufacturer is worse off when suppliers cooperate or share private information. Both suppliers, however, can benefit from cooperation and information sharing.     

Controlling a supplier’s subcontracting decisions through contractual enforcement or economic incentives

Suppliers often subcontract part of their workload to other suppliers, and manufacturers might suffer severe consequences if they do not anticipate their suppliers’ incentives to subcontract. In this paper, we study the case where a manufacturer outsources two tasks to a top-tier supplier. The manufacturer must decide whether it should design a contract that enforces that the different tasks are completed by the appropriate suppliers, and when it is preferable to use economic incentives to manipulate the top-tier supplier’s subcontracting behaviour. We find that when the cost difference between suppliers of different tiers is small and the correlation between the risks associated with the two tasks is minimal, the manufacturer can benefit from designing a contract that ensures the preferred subcontracting behaviour, if the cost of enforcing such a contract is not too high. However, when such enforcement cost is substantial, the manufacturer might be better off manipulating the top-tier supplier’s economic incentives.     

Comparing the lens displacement profile data by using the sequential approach for selecting alternative suppliers

The lens module is a critical part of the camera module. The quality of the lens module significantly influences the auto-focus and image stability functions of the camera module. A new approach that uses sequential tests is proposed to select the alternative suppliers that provide the qualified parts as the current supplier under the linear profile data. Having several qualified alternative suppliers can reduce the dependency on one supplier, improve bargaining power, and reduce capacity risk. The lens displacement that has a linear relationship with current is the quality characteristic for evaluating the lens module suppliers. To select the qualified alternative suppliers, the proposed sequential approach tests the profile difference between the current supplier and the investigated suppliers. The simulation results show that the power of the sequential approach is higher than the simultaneous confidence bands method in differentiating profiles. Last, the proposed approach is effectively applied to select the qualified alternative lens module suppliers for the camera module manufacturer. Procuring the lens module from the selected suppliers can maintain production quality and flexibility for the camera module manufacturer in practice.     

Vendor-managed inventory: a review based on dimensions

Vendor-managed inventory (VMI) represents the methodology through which the upstream stage of a supply chain (vendor) takes responsibility for managing the inventories at the downstream stage (customer) based on previously agreed limits. VMI is another method by which supply chains can be managed, and, owing to centralised decision-making and constant information sharing, the benefits are much higher than in traditional supply chain case. However, there exists a lack of research that identifies the dimensions of VMI, benefits of VMI, methods, and levels used in the VMI environment. The focus of this paper is to explore the existing literature on VMI, to categorise it according to the criteria evaluated, and to present a systematic review. In this study, we have classified the review into three categories such as dimension-based, methodology-based, and level-based. From the thorough literature review, we have identified six dimensions of VMI: namely, inventory, transportation, manufacturing, general benefits, coordination/collaboration, and information sharing. In addition, there are, three methodological classifications: modelling, simulation, and case studies. Finally, we will consider the level-based classification. Based on the review, several recommendations that improve the performance of VMI are presented.