具有随机需求的供应链网络缺货概率的计算方法

由于需求的不确定性及网络的复杂性,使得供应链网络上各企业缺货概率的计算变得非常棘手.将供应链网络模型成Markov过程,利用排队理论提出了供应链网络各企业缺货及因满货而待送货的稳态概率的计算公式;对于较大的供应链网络,提出了将系统分解成2级供应链网络集合求各企业缺货概率的近似方法.这种方法是通过修正各制造商的批量送货间隔时间、各销售商及各零售商的批量销售间隔时间参数,把分解后的子系统与多级供应链网络连接起来,利用子系统求出各企业的缺货和因满货而待送货的稳态概率的近似值.数值试验表明所提出的近似解法具有很高的精度.     

基于(Q,R)补货的双渠道供应链库存模型研究

制造商在引入网络直销渠道后,需有效协调与零售商之间的物流冲突.以销售单一产品,只有一个制造商和零售商,且制造商的补货策略为(Q,R)策略,零售商的补货策略为一对一策略的双渠道供应链系统作为研究对象,在综合考虑消费者渠道偏好和由于销售渠道缺货所引起的消费者转移的前提下,结合Markov过程理论建立供应链系统库存模型,针对制造商和零售商的库存决策进行分析.分析表明,制造商存在R~*及Q~*,零售商存在库存水平S~*使供应链系统的收益最大.MATLAB仿真表明了该结论的有效性.     

基于减排成本共担期权契约的供应链协调

考虑消费者具有低碳产品偏好的情况,研究需求随机且受减排影响的期权契约,建立了由单个制造商和单个零售商组成的供应链模型。该模型中制造商处主导地位,零售商处追随地位,制造商首先提出期权契约,零售商购买期权。求解发现,由于传统双重边际化效应的存在,只有当零售价格等于期权执行价格时,才能达到供应链的协调,这时零售商利润为负,不满足参与约束。为此,从降低期权执行价格的角度,对期权契约进行补充,增加了成本共担条款。研究表明,减排成本共担的期权契约能够实现供应链的协调。最后利用算例验证了结论,计算了制造商和零售商利润及零售商分担的减排成本比例随期权价格和期权执行价格的变化情况,并对减排难度系数的敏感性做了分析。     

基于技术选择与信息反馈的供应链碳减排研发决策比较

考虑延伸服务与信息反馈情况下,针对单个制造商和两个竞争零售商的供应链决策问题,构建了需求不确定情况下研发技术决策的供应链非合作竞争博弈模型,得到了制造商和零售商在三种不同溢出情况下的最优研发决策.通过理论和算例分析了不同的减排研发技术与供应链成员利润的相关关系,并探讨了减排研发成本系数与产品替代系数对供应链成员的策的影响.     

Downside-risk测度下 闭环供应链风险共享契约研究

以具有下游风险的零售商和风险中性的制造商组成的闭环供应链系统为背景,分析提出了在Downside-risk约束下收益共享契约和批量折扣契约都不能使闭环供应链达到协调状态的结论.设计了一种收益共享和转移支付的组合机制来减轻风险约束的影响,使制造商和零售商能够达到双赢的结果,实现风险控制和闭环供应链协调.最后,通过数值分析验证了组合机制的可行性和有效性.     

带有常数返回率的动态易逝品供应链协调模型

以动态易逝品为研究对象,探讨了由单个制造商单个零售商所组成的两层供应链生产订购协调问题.在假定零售商所售产品存在返回的前提下,分别建立了集中决策和分散决策模型,并证明了这两个模型解的存在唯一性.提出了一个两阶段的收益共享契约,该契约不仅能达到供应链协调,而且还能实现供应链两成员的"双赢".最后,通过数值实例来验证模型的结论并得出相关管理启示.     

碳限额政策下一个制造商和两个零售商的供应链定价决策

研究了碳限额政策下一个制造商和两个零售商构成的二级供应链.根据制造商差别定价或统一定价及两个零售商竞争或合作构建了4个博弈模型,利用逆向归纳法得到了各个模型的均衡决策并进行了比较分析.结果表明:1)制造商的利润在制造商差别定价两个零售商竞争时最大,而在制造商统一定价两个零售商合作时最小.2)供应链的利润在制造商统一定价两个零售商合作时最大,而在制造商差别定价两个零售商竞争时最小.最后,通过数值实验分析了碳限额对供应链成员利润的影响.     

供应链金融三方风险控制的CVaR决策分析——基于预付账款融资模式

研究基于预付账款融资模式下的供应链金融三方决策问题,采用CVaR的风险度量准则作为决策标准,建立了随机需求下的单个风险规避零售商、单个风险规避制造商及单个风险规避银行组成的供应链金融风险模型.在权衡收益和风险的基础上,得出零售商的最优订购量、制造商的最优批发价格及银行的最优利率.研究以零售商是否存在违约为前提,通过对三方收益的分析,在考虑风险规避水平的同时,求解出最优订购量、批发价格和利率,并研究它们之间的关系.最后,通过Matlab数值仿真验证预付账款模式下CVaR模型的合理性.     

销售市场和回收市场同时扰动下的闭环供应链协调应对

考虑一个闭环供应链由单个制造商和单个零售商组成,产品的制造和再制造由制造商负责,产品的销售和废旧品的回收由零售商负责。在建立博弈模型的基础上,首先分析了闭环供应链在收益共享契约下的协调性,接着分析了收益共享契约对突发事件下闭环供应链的协调应对。分析结果表明:当突发事件导致销售市场规模和废旧品回收市场初始规模同时发生变化时,闭环供应链的协调将被打破,为此对收益共享契约进行了调整,调整后的收益共享契约使闭环供应链具有抗突发事件性;最后,通过数值计算实例对此进行了验证分析。     

基于广告、技术、奖励的二级供应链效益最大化研究

研究了做广告、引进先进技术、奖励员工对供应链效益影响问题.针对单个制造商与单个零售商组成的二级供应链,基于弹性需求,在促销-价格敏感需求、质量-敏感需求与奖励-敏感成本条件下构建模型.以整个供应链的利润之和最大,且制造商与零售商利润之差的平方和最小为目标.首先,通过Lagrange数乘法求解,判断对应的Hesse矩阵.其次,确定了广告、技术与奖励员工的最佳投入量,实现供应链效益最大化,提高供应链的经济效益.同时,也通过收益共享,实现供应链的协调性,优化供应链产业结构.最后运用数值实验来具体说明各因素对供应链最大效益的影响.     

A periodic-review inventory control policy for a two-level supply chain with multiple retailers and stochastic demand

We consider a time-based inventory control policy for a two-level supply chain with one warehouse and multiple retailers in this paper. Let the warehouse order in a fixed base replenishment interval. The retailers are required to order in intervals that are integer-ratio multiples of the base replenishment interval at the warehouse. The warehouse and the retailers each adopt an order-up-to policy, i.e. order the needed stock at a review point to raise the inventory position to a fixed order-up-to level. It is assumed that the retailers face independent Poisson demand processes and no transshipments between them are allowed. The contribution of the study is threefold. First, we assume that when facing a shortage the warehouse allocates the remaining stock to the retailers optimally to minimize system cost in the last minute before delivery and provide an approach to evaluate the exact system cost. Second, we characterize the structural properties and develop an exact optimal solution for the inventory control system. Finally, we demonstrate that the last minute optimal warehouse stock allocation rule we adopt dominates the virtual allocation rule in which warehouse stock is allocated to meet retailer demand on a first-come first-served basis with significant cost benefits. Moreover, the proposed time-based inventory control policy can perform equally well or better than the commonly used stock-based batch-ordering policy for distribution systems with multiple retailers.     

Managing inventory and service levels in a safety stock‐based inventory routing system with stochastic retailer demands

The inherent uncertainty in supply chain systems compels managers to be more perceptive to the stochastic nature of the systems' major parameters, such as suppliers' reliability, retailers' demands, and facility production capacities. To deal with the uncertainty inherent to the parameters of the stochastic supply chain optimization problems and to determine optimal or close to optimal policies, many approximate deterministic equivalent models are proposed. In this paper, we consider the stochastic periodic inventory routing problem modeled as chance‐constrained optimization problem. We then propose a safety stock‐based deterministic optimization model to determine near‐optimal solutions to this chance‐constrained optimization problem. We investigate the issue of adequately setting safety stocks at the supplier's warehouse and at the retailers so that the promised service levels to the retailers are guaranteed, while distribution costs as well as inventory throughout the system are optimized. The proposed deterministic models strive to optimize the safety stock levels in line with the planned service levels at the retailers. Different safety stock models are investigated and analyzed, and the results are illustrated on two comprehensively worked out cases. We conclude this analysis with some insights on how safety stocks are to be determined, allocated, and coordinated in stochastic periodic inventory routing problem. Copyright © 2017 John Wiley & Sons, Ltd.     

Stability and monotonicity in newsvendor situations

This study considers a supply chain that consists of n retailers, each of them facing a newsvendor problem, and a supplier. Groups of retailers might increase their expected joint profit by joint ordering and inventory centralization. However, we assume that the retailers impose some level of stock that should be dedicated to them. In this situation, we show that the associated cooperative game has a non-empty core. Afterwards, we concentrate on a dynamic situation, where several model cost parameters and the retailers’ dedicated stock levels can change. We investigate how the profit division might be affected by these changes. We focus on four monotonicity properties. We identify several classes of games with retailers, where some of the monotonicity properties hold. Moreover, we show that pairs of cooperative games associated with newsvendor situations do not necessarily satisfy these properties in general, when changes in dedicated stock levels are in concern.     

考虑零售商竞争的供应链契约选择模型

传统的面向竞争性供应链协调的契约设计的高复杂度使得契约学习的成本大大提高,难以在现实中得到普遍应用。研究了由一个供应商和两个竞争性零售商构成的供应链的协调问题。分析了竞争性零售商对简单契约的选择问题,设计了一种不同于以往单一契约模式的契约选择模型,为订货能力不同的零售商提供可供选择的数量折扣契约和批发价格契约。实现了供应链的最优协调,使分散式决策的供应链的利润达到了集中决策的水平。最后通过具体算例验证了结论。     

风险时收益共享-贸易信贷契约下多个竞争零售商的供应链协调

在供应商向多个零售商提供贸易信贷的环境下,本文考虑了零售商存在违约风险和他们之间存在竞争时的供应链协调问题。研究表明,在比例分配市场需求下,多个竞争的零售商之间存在唯一的纳什均衡订购量,以及零售商违约风险的提高和他们之间竞争增强都会增加均衡订购量。当零售商之间的竞争较弱时,贸易信贷将无法协调供应链。为此,本文使用了收益分享与贸易信贷相结合的机制以协调供应链,且分析了零售商的违约风险和他们之间的竞争对协调契约参数的影响。当零售商的竞争强度一定时,批发价和风险溢价都随着零售商违约风险的提高而增大,而收益分享比例随着违约风险的提高而减小;当零售商的违约风险一定时,批发价和风险溢价都随着零售商之间竞争强度的提高而增大,而收益分享比例随着竞争强度的增强而减小。进一步的研究发现,零售商的违约风险越高以及他们之间竞争越激烈对零售商越不利,而对供应商越有利。最后,结合数值实验验证了收益共享-贸易信贷契约的有效性。     

存货质押融资模式下的供应链协调

针对供应商、零售商和银行组成的供应链金融系统,研究了存货质押融资模式下的供应链协调。零售商作为中小企业,资金有限,需要向银行申请贷款,然而零售商信用较低难以获得融资。供应商作为供应链的核心企业,采用含有回购价格和回购比例的回购契约为零售商提供担保,使得零售商融资得以实现。分析了不确定需求下供应链金融系统,供应链以及零售商的最优决策,给出了融资情况下供应链协调的条件,指出了在供应链协调情况下批发价格和回购策略对供应链收益分配的影响,说明了回购的作用:一方面使零售商易于获得银行融资,另一方面使供应链协调得以实现,指出了质押率、贷款利率和零售商自有资金等参数对最优决策的影响。数值算例验证了理论分析结果。     

竞争环境下基于双重微分博弈的低碳供应链动态优化与协调

在节能减排背景下考虑制造商低碳生产、零售商宣传竞争的情形,将碳减排量以及商誉作为状态变量,借助微分博弈研究供应链动态优化与协调问题。针对双重边际化效应,通过引入成本共担契约对供应链进行协调。研究表明,引入契约后零售商处的低碳宣传努力水平提高、低碳商誉提升、需求量增加,供应链利润基本达到集中决策水平;随着竞争程度的增加,市场需求量提高,制造商利润增加,供应链整体利润提高,启发供应链企业在决策过程中创造良性竞争环境、形成良性竞争机制。     

A genetic algorithm for a single product network design model with lead time and safety stock considerations

We consider a two-stage supply chain with a production facility that replenishes a single product at retailers. The objective is to locate distribution centers in the network such that the sum of facility location, pipeline inventory, and safety stock costs is minimized. We explicitly model the relationship between the flows in the network, lead times, and safety stock levels. We use genetic algorithms to solve the model and compare their performance to that of a Lagrangian heuristic developed in earlier work. A novel chromosome representation that combines binary vectors with random keys provides solutions of similar quality to those from the Lagrangian heuristic. The model is then extended to incorporate arbitrary demand variance at the retailers. This modification destroys the structure upon which the Lagrangian heuristic is based, but is easily incorporated into the genetic algorithm. The genetic algorithm yields significantly better solutions than a greedy heuristic for this modification and has reasonable computational requirements.     

Optimal production and rationing decisions in supply chains with information sharing

This paper considers a two-echelon capacitated supply chain with two non-identical retailers and information sharing. We characterize the optimal inventory policies. We also study the benefits of the optimal stock rationing policy over the first come first served (FCFS) and the modified echelon-stock rationing (MESR) policies.     

Trade credit competition between two retailers in a supply chain under credit-linked retail price and market demand

The paper considers a supply chain system in which the sole manufacturer supplies the same product to two retailers who compete in offering trade credit period to customers. Both the market demand and retail prices vary with the trade credit periods offered by the retailers. The manufacturer also provides a trade credit period to both the retailers to settle down their accounts. The net profit function of the supply chain is derived considering possible relationships among the trade credit periods offered by the manufacturer and the retailers and the time when each retailer receives the last payment from his customer. An algorithm is developed to find the optimal solution of the proposed model. From the numerical study, it is observed that a two-level trade credit financing can increase profits not only for the manufacturer and the retailers but also for the whole supply chain.