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.     

基于供应链的企业库存成因及优化控制的研究（一）

基于企业全面库存的管理思想,对库存成本、库存控制、库存系统优化等管理经验与前人研究成果进行分析,借鉴先进企业的库存管理理念和方法,以大型制造企业为核心研究对象,在集供应商、制造商、经销商为一体的供应链作为研究框架的基础上,运用供应链系统理论作为研究方法,分析了库存管理现状、影响因素及产生原因,从优化生产管理、整合企业内部供应链和跨企业供应链的角度提出了库存控制的相应对策,以实现全面的库存优化,提高经营效益。     

基于供应链的企业库存成因及优化控制研究（二）

基于企业全面库存的管理思想,对库存成本、库存控制、库存系统优化等管理经验与前人研究成果进行分析,借鉴先进企业的库存管理理念和方法,以大型制造企业为核心研究对象,在集供应商、制造商、经销商为一体的供应链作为研究框架的基础上,运用供应链系统理论作为研究方法,分析了库存管理现状、影响因素及产生原因,从优化生产管理、整合企业内部供应链和跨企业供应链的角度提出了库存控制的相应对策,以实现全面库存优化,提高经营效益.     

随机需求条件下供应链的补货及折扣策略研究

研究一个供应商和多个零售商围绕单品种商品组成的供应链体系中,以供应商为核心的供应链库存管理,目标是通过直接降低供应商的库存成本,从而降低供应链的总成本.假设每个零售商面对服从随机正态分布的提前期客户需求,在不考虑交货时间的情况下,供应商在固定的时间间隔满足零售商的补货需要,并以价格折扣的方式补偿零售商的成本增加.由此得到较优的补货间隔,并给出了求解方法.最后,通过仿真验证了该解法的可行性并评估了该策略对各方的影响.     

供应商管理库存的供应链管理绩效模型

使用多目标规划的方法描述了供应链及其成员的运作性能、供应链的协调运作、供应链成员的利润等,建立了由一个制造商和一个供应商构成的多产品、多阶段供应商管理库存的供应链管理绩效模型;通过应用算例的研究验证了模型的有效性和可行性;并与未实行供应商管理库存的供应链管理绩效模型进行比较,验证了供应商管理库存能够提高供应链的绩效.     

供应链视角下工程材料库存优化研究

目的为了达到节约工程建设行业企业材料管理成本的目的,以常用的2种工程材料钢材和水泥存储于同一仓库且由同一供应商供货的库存管理为研究对象进行研究。方法分析承包商采购材料情形下,供应商和承包商基于合作伙伴关系实现库存信息共享,建立2种材料两级库存联合库存成本优化的数学模型,并通过工程实例,运用粒子群算法求解,验证研究方法的有效性。结果不同的材料订购策略对工程供应链上的材料库存成本影响很大,数学模型可以给出恰当的订购策略,满足系统成本的最低要求,从而节约成本,提升工程供应链的整体竞争力。结论研究成果丰富了工程供应链管理理论、工程材料的库存管理理论,并对工程建设实践中的材料采购有一定的指导意义。     

电子商务环境下两级供应链库存管理决策研究

本文利用order up to level策略建立需求不确定时两级供应链供应商的库存策略模型并进行参数求解,给出最优库存水平以及管理绩效考核指标的求解方法。并通过实例计算,给出电子商务环境下基于两级供应链的供应商库存最优解决方案,提出随着零售商需求波动程度、库存水准的变动,对于供应商最优库存水平、库存成本、缺货成本的相应策略。     

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.     

基于供应链技术的铜盘管季节性库存问题研究

总结铜盘管市场特点,详细分析季节性库存过程中存在的库存产品积压风险、库存产品质量风险、铜价波动风险以及资金短缺风险,提出利用供应链库存管理技术、延迟化策略、套期保值、融通仓等现代供应链管理理论来降低季节性库存所面临的各种风险。     

基于VMI的供需双方利益分配模型

针对解决实施供应商管理库存策略短期内合作双方的责任与利益不统一的问题,在分析库存成本模型,证明该策略能够降低供应链库存成本的基础上,根据双方优势地位的不同,建立了短期内供需双方利益分配模型,并进行了实证研究.该模型对于建立供应商零售商双方稳定的合作关系具有重要的理论与现实意义.     

基于横向补货的库存协调近似模型

以给定零售商独自拟定订货策略为前提,提出了一种在横向补货允许的情况下,能够有效地刻画系统库存的近似模型.该模型在"最近邻居"优先补货原则下,详细地阐述了系统中的产品需求走势和相应的需求满足率.并通过和仿真试验的数值结果进行比较,验证了该模型的有效性,还对横向补货允许和补货不允许两种不同情况下的系统库存成本进行了比较,形象地给出了横向补货策略在优化库存成本方面的绩效.关于单个零售商订货策略一般性的拓展以及系统联合订货策略的可能性研究也给予了相关说明.     

需求正态分布下包装延迟策略对库存影响的研究

探讨了在需求正态分布下不同包装策略下的库存量计算方法,并对相同的需求不确定性、需求相关系数、包装分布下包装延迟策略对库存的影响进行了分析比较.通过比较发现包装延迟策略在客制化需求日益增加的情况下,包装延迟策略能在一定程度下降低库存,为企业带来一定的收益.     

Innovative vendor-managed inventory strategy exploiting interconnected logistics services in the Physical Internet

Traditional supply chain networks are often designed in the interests of a company. Once the network has been defined, the storage and distribution of goods are usually fixed and restricted within the network. This is assumed to be an inherent limit of current inventory control research. Instead of specialised hierarchical storage networks, this paper proposes an innovative vendor-managed inventory strategy exploiting the Physical Internet (PI), which is an open, universal, interconnected logistics system. In such a system, facilities and means of transport are shared and can be allocated according to demands of users. As a result, the PI allows users to stock anywhere in the network and also provides open multisourcing options for orders with on-demand warehousing services within the PI. Inventory decisions can be made dynamically by each player to minimise networkwide inventory levels. A non-linear, simulation-based optimisation model was developed for the vendors’ inventory decision-making when confronted with stochastic demands. A metaheuristic using simulated annealing was applied to solve the problem, and then, the optimised inventory decisions were validated using simulation. The results suggest that the proposed PI inventory model can reduce the total logistics cost while maintaining a comparable or better level of end customers’ services.     

Multiple criteria ABC inventory classification using two virtual items

ABC inventory classification is one of the most popular techniques for organisations to efficiently plan and control thousands of inventory items. Its traditional way is solely based on a single criterion; however, it has been recognised that multiple criteria need to be considered in practice. An alternative approach to multiple criteria inventory classification (MCIC) is proposed by using two virtual items and incorporating the TOPSIS. The proposed approach improves some previous allied methods as it provides a more reasonable and comprehensive performance index and a unique inventory classification without any subjectivity. Comparisons with other allied methods are illustrated through a case study.     

Inventory management in a lateral collaborative manufacturing supply chain: a simulation study

Due to global competition, firms are seeking more effective supply chain (SC) collaboration in order to provide quality products with less cost, at the right time and in the right quantity. The present study examines manufacturing SC collaboration on the basis of holding cost, backorder cost and ordering cost. The types of collaboration examined are vertical, horizontal and lateral collaboration. This research emphasises lateral collaboration by determining the impact of inventory policies ((s, S) and (s, Q) inventory policies) on SC performance. For better understanding, a conceptual model is provided that is supported by a numerical example. As the study of SCs is complex in nature, a simulation approach has been employed to show the impact of lateral collaboration on performance measures such as the total cost, which is the sum of several cost components: inventory holding cost, backorder cost and ordering cost. The research is based on two manufacturing SCs where the manufacturer is taken as the collaborative node. To allow more clarity, a separate study on each cost component has been conducted. The laterally collaborative SC was simulated on ARENA 9.0, a simulation package. The results show that the efficacy of lateral collaboration outperforms horizontal collaboration due to having the individual SC members at more liberty to make decisions.     

Inventory performance of some supply chain inventory policies under impulse demands

This paper attempts to study the impact of impulsive demand disturbances on the inventory-based performance of some inventory control policies. The supply chain is modelled as a network of autonomous supply chain nodes. The customer places a constant demand except for a brief period of sudden and steep change in demand (called demand impulse). Under this setting, the behaviour of each inventory policy is analysed for inventory performance of each node. It is found that the independent decision-making by each node leads to a bullwhip effect in the supply chain whereby demand information is amplified and distorted. However, under a scenario where the retailer places a constant order irrespective of the end customer demand, the inventory variance was actually found to decrease along the supply chain. The variance of the inventory remained constant along the chain when only the actual demands are transmitted by each node. The results also showed that the inventory policy which is best for one supply chain node is generally less efficient from a supply chain perspective. Moreover, the policy which performs poorly for one node can be most efficient for the supply chain. In a way, our results also provide a case for coordinated inventory management in the supply chain where all members prepare a joint inventory management policy that is beneficial for all the supply chain nodes. The results have significant industrial implications.     

Approximation of the probability distribution of the customer waiting time under an (r,s, q) inventory policy in discrete time

We study a single-item periodic review (r, s, q) inventory policy. Customer demands arrive on a discrete (e.g. daily) time axis. The replenishment lead times are discrete random variables. This is the time model underlying the majority of the Advanced Planning Software systems used for supply chain management in industrial practice. We present an approximation of the probability distribution of the customer waiting time, which is a customer-oriented performance criterion that captures supplier–customer relationships of adjacent nodes in supply chains. The quality of the approximation is demonstrated with the help of a simulation experiment.     

基于随机替代关系的单周期可替代品库存模型

基于确定型的可替代产品单周期库存模型已有研究,它假定替代数量关系是确定的。而事实上,替代过程中由于消费者需求的个性化因素影响,替代的数量关系往往是随机的。为此,假定替代数量关系符合随机分布条件下,提出了两类可替代产品的单周期库存模型,并设计了基于遗传算法的仿真优化算法。算例分析的结果表明,考虑随机替代关系可显著地提高决策者的收益;该算法是有效的。     

Switchgear component commonality design based on trade-off analysis among inventory level,delivery lead-time and product performance

The shortening of product delivery lead-times can usually be achieved by keeping high-level components in inventory, however in small-volume production systems, maintaining such inventories is often a costly as well as a risky business strategy. If the risk of maintaining unsold inventory can be decreased, even small-volume manufacturers may be able to justify holding more significant quantities of versatile inventory. This paper discusses a component commonality effect to breakthrough the trade-off relationship between inventory levels and delivery lead-times for such small-volume production systems. By using the same component in different products, inventory maintenance costs can be dramatically reduced, but component commonality design problems are inherently complex, since excessive module commonality may lead to lower product performances, and there are trade-off relationships between product performance and cost reductions obtained through component commonality. In this paper, such a design problem is formulated as a multiobjective component commonality design optimisation problem considering inventory level, delivery lead-time and product performance, and the optimal solutions are obtained as a Pareto optimal solution set. Detailed procedures concerning the proposed design method, including inventory simulation, are discussed and developed for a switchgear design problem. Finally, an example switchgear design problem is solved to illustrate that optimal use of component commonalities across different modules can significantly reduce inventory costs, while also shortening product delivery lead-times.     

Zero inventory and firm performance: a management paradigm revisited

According to the ‘zero inventory’ paradigm, inventory reflects waste and should be eliminated in order for performance to rise. In this study, we investigate the effect of inventory holding on firm performance, analysing 3057 firm years of data. Interpreting performance as a function of inventory, results show that firms with the lowest inventory have the worst performance (and vice versa). When understanding inventory as a function of performance, results indicate that low-performing firms carry the least inventory, whereas high-performing firms have the highest stocks. Besides questions of causality, our results do not support a paradigm which suggests that firms should move toward zero inventory.