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.     

供应商管理库存的价格效应研究

通过建立数学模型,论证了VMI在供应链中收益的非负性;在此基础上还给出了供求均衡价格与订货成本比、库存成本比的函数关系,该公式说明当订货成本比与库存成本比相差比较大时,VMI可以有效降低均衡价格,否则均衡价格将会上升。     

存货影响销售量的两阶段供应链的VMI协调

研究在VMI环境下存货影响销售量的单供应商、单零售商的两阶段供应链的协调问题。建立了集中决策下的供应链模型,求出了整体供应链的利润函数;在分散决策下,采用收益共享契约对供应链进行协调,按Stackelberg博弈方式进行建模分析,发现收益共享契约无法协调供应链,即在利益分配上,与供应商相比,零售商获得了更多的供应链收益,而且分散式系统的收益始终低于集中决策下的水平;采用Nash协商对VMI供应链进行协调,完成了供应商和零售商收益的帕累托改进,不仅实现供应链的协调,而且达到了集中决策下的水平,最后通过算例进行了验证。     

An analysis of the general benefits of a centralised VMI system based on the EOQ model

Within a vendor-managed inventory (VMI) agreement, the upstream supply chain member (the vendor) takes responsibility for managing the inventory of the downstream member (the customer) within specific levels previously agreed upon without the need of orders from the customer side to be placed. Therefore, the vendor can focus on optimising production efficiency and capacity planning, while the customer has to improve forecast accuracy. This paper analyses the benefits a VMI agreement could bring for a one-supplier, multiple-customer case through analysing two cases: a supply chain managed in a traditional manner and VMI when both the vendor and the customers belong to the same organisation. The analysis is based on the economic ordering quantity (EOQ) formula and its related total cost, and the novelty is captured by evaluating one vendor, multiple buyers, and multiple product situations. The modelling is done so as to capture the needs and factors which occur within the pharmaceutical industry and a numerical application will be executed with data from one of the main leaders within the pharmaceutical field.     

Vendor-managed inventory with consignment stock agreement for single vendor–single buyer under the emission-trading scheme

This paper presents a joint economic lot size (JELS) model for coordinated inventory replenishment decisions under the vendor-managed inventory (VMI) with consignment stock (CS) agreement and an emission-trading scheme. The paper assumes a single product that flows along a two-level supply chain system, with a single vendor and a single buyer. The total cost of the system is the performance measure, which is the sum of the vendor’s and the buyer’s total costs. The total cost includes the set-up and order costs, inventory holding costs, greenhouse gases (GHG) emissions tax and penalty costs. A mathematical model is proposed to determine: (1) the vendor’s production lot size quantity; (2) the number of shipments sent by the vendor to the buyer in a cycle; and (3) the production rate that minimises the total cost of the supply chain. Some numerical examples are carried out, as well as comparisons with the traditional JELS model for a classic two-level supply chain. Results show that the performance of the system is better when it is operated under a VMI with CS agreement, which is capable of reducing the traditional inventory holding costs and, for some values of given parameters, the GHG emissions tax and penalty costs.     

A supply chain model with vendor-managed inventory,consignment, and quality inspection errors

This paper considers the integration between quality control and production inventory control in supply chain management. Specifically, we study the effect of inspection errors on the costs incurred in a supply chain system with a single vendor and multiple buyers. In this system, the vendor enters into a vendor-managed inventory (VMI) and a consignment stock (CS) partnership with several buyers. We assume that the items made by the vendor are not in perfect quality, but they contain a given proportion of defective units. We also assume that quality inspection of these items by the buyers is subject to sampling errors. Three cases indicating to different levels of supply integration are considered: VMI–CS system, traditional system and integrated system. For each case, a mathematical model is formulated, an optimum solution is developed, and a numerical example is solved.     

Decision support system for vendor managed inventory supply chain: a case study

Vendor-managed inventory (VMI) is a widely used collaborative inventory management policy in which manufacturers manages the inventory of retailers and takes responsibility for making decisions related to the timing and extent of inventory replenishment. VMI partnerships help organisations to reduce demand variability, inventory holding and distribution costs. This study provides empirical evidence that significant economic benefits can be achieved with the use of a genetic algorithm (GA)-based decision support system (DSS) in a VMI supply chain. A two-stage serial supply chain in which retailers and their supplier are operating VMI in an uncertain demand environment is studied. Performance was measured in terms of cost, profit, stockouts and service levels. The results generated from GA-based model were compared to traditional alternatives. The study found that the GA-based approach outperformed traditional methods and its use can be economically justified in small- and medium-sized enterprises (SMEs).     

跨境VMI供货模式下生产-库存联合优化研究

研究基于跨境VMI(vendor managed inventory)供货模式下的生产-库存联合优化问题。以一个实际案例企业作为应用背景,比较了VMI供货模式和传统的供货模式在海运和空运2种运输方式下的不同特点及其对决策的影响。研究结果表明,对于案例企业而言,采用VMI供货模式的库存管理是可行的,考虑目前公司采用2种可选的运输模式,选择海运的总成本最低。通过对资金费用率、库存费用比率和缺货费用率进行灵敏度分析,探讨了不同环境变量对最优决策的影响。研究结果对跨境供应链多国生产型企业改善跨境物资采购和生产-库存决策有一定参考价值。     

Vendor-managed inventory and the effect of channel power

We analyze decentralized supply chains that follow general continuous review (Q, R) inventory policies subject to vendor-managed inventory agreements where the supplier chooses the order quantity Q, and the retailer chooses the reorder point R. Within the VMI scenario, we explore the effect of divisions of channel power on supply chain and individual agent performance by examining different game theoretic models. Optimal policies and analytical results, including existence and uniqueness proofs for equilibrium solutions under VMI, are derived. Numerical results are provided to compare the effectiveness of VMI and to analyze different channel power relationships under a variety of environmental conditions. We find that VMI can result in considerable supply chain savings over traditional relationships and that the relative division of channel power can significantly effect the performance of VMI. Interestingly, we find that the greatest system benefits from VMI arise in asymmetric channel power relationships, but that individual agents lack the incentive to assume a leadership role.     

供应链管理中VMI系统的研究

通过分析VMI和RMI在概念原理上的本质差异,讨论了VMI在管理思想、决策方式、预测体系、补货模式、延迟策略方面的优越性和先进性。在此基础上,详细描述了VMI工作流程中的八个关键环节,并结合实际指出实施VMI的步骤和注意事项,最后总结了VMI在实践中给供应商、零售商以及供应链整体带来的收益和竞争优势。     

A green vendor-managed inventory analysis in supply chains under carbon emissions trading mechanism

One of the most important strategies for reducing carbon emissions is to optimize firms’ operation decisions in business practices. This paper proposes a green vendor-managed inventory (a green VMI) model with a supplier and a manufacturer under a carbon emissions trading mechanism. The proposed model integrates both environmental and economic goals under a carbon emissions constraint, and then the members’ optimal decisions are obtained. Comparing this model with the traditional VMI model, this paper finds that, in the green VMI model, whether the supplier should sell or buy carbon credit depends on the carbon cap. Further, the impacts of the carbon cap and the carbon emissions factors on the optimal decisions, the carbon emissions, and the total costs in the supply chain are examined analytically. Finally, numerical experiments are performed to verify the theoretical results. It is shown that, after introducing the carbon trading mechanism, the VMI model could increase the total cost of the supply chain under some specified set of parameters.     

供应链虚拟库存决策的仿真

在供应链延迟策略和供应商管理库存（VMI）策略研究的基础上,建立了供应链延迟策略下的仿真模型,再引入虚拟库存,通过计算机仿真,探讨了虚拟库存实施前后供应链绩效的变化情况。研究结果表明,与一般的供应商管理库存相比,虚拟库存的引入使得供应链总成本和企业的服务水平均有所增加。     

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.     

供应链上游段VMI模式的共赢条件

选取上游层面VMI模式各参与者为研究对象.考虑实施上游层面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.通过建立数学模型,对实施上游层面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,各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,也能使各制造商和供应商的经济效益都有所提高,实现共赢,为各企业更加长久的合作提供理论依据.     

VMI versus information sharing: an analysis under static uncertainty strategy with fill rate constraints

A vendor-managed inventory (VMI) relationship between a downstream retailer and an upstream vendor consists of two distinct components: (i) information sharing (IS) and (ii) a shift in decision-making responsibility. This study compares these two components of VMI in a two-stage serial supply chain based on the ‘static uncertainty’ strategy under dynamic and random demand with fill rate constraints. Numerical experiments are conducted using analytical models to identify the conditions where the incremental value of VMI over IS is significant. The results provide guidelines relevant to academia and supply chain practitioners in taking VMI adoption decision above and beyond IS according to their specific business environment.     

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.     

Flexible work-in-process production system in supply chain management under quality improvement

For a complex product production, any flexible manufacturing system with a work-in-process inventory is recommended for a supply chain management (SCM) system. Building a flexible manufacturing system increases the total cost of the supply chain; for this reason, a discrete investment is important. For flexible production systems, production rate within a finite specific interval of production rate as work-in-process inventory is calculated. The aim of the supply chain is to reduce the total cost when demand during the lead time is a random variable with a normal distribution. A crashing cost is utilised to reduce the duration of lead time within the supply chain system. A model is proposed to obtain the optimal flexible production rate with the reduced total cost of the supply chain. A classical optimisation technique is employed to obtain the closed-form and quasi-closed-form solutions of the decision variables. An improved algorithm is designed to obtain the global minimum cost of SCM under the framework of a flexible production system. An illustrative numerical example and sensitivity analysis are given to test the model. A numerical study proves that this model obtains the minimum cost with the optimal decision variables.     

VMI下需求受库存和努力水平影响的供应链协调

针对一个实施VM I(供应商管理库存)的两级供应链,市场需求受供应商和零售商双重努力影响的问题,建立了基于协作关系的库存和努力水平决策模型。通过分析得出在分散决策下供应商选择的库存水平和零售商选择的努力水平均低于集中决策下的最优水平,供应链效率也较低。设计了一个成本分摊契约协调供应链。结果表明,该契约能将供应商和零售商紧密地联系在一起,且通过供应商和零售商的共同努力能获得比分散式决策下更大的利润。     

基于制造延迟的VMI模型的仿真研究

在供应链延迟策略和供应商管理库存(VMI)策略研究的基础上,首先建立了供应链延迟策略下的仿真模型,然后再引入供应商管理库存策略,通过计算机仿真,探讨了供应商管理库存策略实施前后供应链绩效的变化情况.研究结果表明,与单纯的延迟策略相比,延迟与供应商库存相结合的策略能明显改善供应链的绩效.     

供应链系统重构模式研究

从系统集优的观点出发，按照精干业主、合理配置资源、提高效率、协调运行的原则，分析了电子商务环境下供应链系统重构的目标模式和基于目标模式的系统重构的组织结构模式与物流管理模式，结果是组织结构VMI-TPL模式较适合于一般供应链系统的重构，而TPL-TPL模式较适合于某些特殊情况下的供应链系统的重构，进而提出了相应的物流管理模式。