易腐品供应链企业联合采购决策与费用分配研究

在激烈的市场竞争中,如何降低成本以及保证产品的新鲜度对于销售易腐性产品的零售商来说具有至关重要的意义.企业间通过实施联合采购可以降低采购成本,增加与供应商的谈判议价能力,因此联合采购受到越来越多的企业以及学者的关注.考虑了在非瞬时补货情况下多零售商向同一供应商联合采购某种易腐品的订货决策及费用分配问题.以易腐品联合采购过程中产生的订货费用作为分配的对象,应用合作博弈理论,将非瞬时补货情况下易腐品联合采购的费用分配问题构造成易腐品的联合采购博弈,证明了该博弈的核心非空且为子模博弈,并给出了核心中的一个分配方案,同时还讨论了补货速率对零售商分担的订货费用的影响.论文最后对几种典型的比例分配解的效率进行了模拟分析.     

基于两级信用支付的易腐品联合采购博弈分析

延期支付作为供应链内部融资的重要渠道之一,广泛存在于商业活动中.在一个由单供应商和多个零售商组成的易腐品供应链中,供应商允许零售商延期支付货款;每个零售商有两类顾客,终端顾客,即直接的消费者,在收到货物之时立即支付货款,中级顾客,即代理商或加盟店,在一定的期限后缴纳货款,如何确定最优订货批量以使得资金实现最大的时间价值是每个零售商面临的重要问题.为此,文章首先研究了在各零售商独立采购时基于两级信用支付的库存模型;其次,研究了多零售商组成联盟实施联合采购时的订货决策问题,应用合作博弈理论,将联合采购下的费用分配问题构造成基于两级信用支付的易腐品联合采购博弈.研究表明,与各零售商独立采购相比,联合采购降低了各零售商的总费用,提高了产品的补货频率,减少了由产品变质带来的损失.     

基于收益共享契约的零售商押金补货策略研究

押金补货是指零售商在第一阶段向供应商交纳一定的押金,在接下来的阶段中不需要再交纳额外的补货费用的补货方式。对于中小型零售商,它的补货策略往往受到自有资金的约束,当自有资金不足以订到报童模型的最优补货量时,不仅自身收益受到影响,还会影响到整条供应链的收益,本文研究了在随机市场需求,且零售商能够随时向银行贷款的情况下,基于收益共享契约的零售商的押金融资订货策略。本文从两阶段出发,分析零售商的最优订货策略,研究表明,零售商的补货策略受初始资产和收益共享系数的影响。最后,文章将其扩展到多阶段问题进行讨论。     

带短期价格折扣和允许两次特殊补货的库存决策模型

针对供应商提供短期价格折扣且允许零售商两次特殊补货的库存系统, 建立了以零售商库存效益最大化为目标的库存决策模型, 分析了模型的性质, 根据经济订单批量补货决策下补货时间点与折扣时段的关系, 确定了零售商在不同补货策略下的库存效益增值函数. 据此给出零售商相应的最优补货策略函数表达式, 提出了该模型的一个全局优化算法, 并通过数值算例验证了模型和算法的有效性与可行性.     

回购契约下双资源渠道供应链协调

分析了零售商既可以从供应商处采购产品同时也可以自己生产的供应链协调问题.提出了回购契约协调该供应链.研究发现,协调回购契约的结构与零售商的需求和产量的随机特征无关,零售商生产和不生产两种情况下的协调回购契约的结构也相同.进一步在假设零售商的需求和产量均为均匀分布下,分析了协调回购契约下零售商的随机产量的价值、零售商的利润和供应商的利润关于批发价和供应商的单位生产成本的变化趋势.     

线性数量折扣下零售商合作的联盟稳定性研究

在激烈的市场竞争中,通过降低原材料的采购成本来降低生产成本成为中小企业增加利润率水平和提高市场竞争力的重要手段之一.因此,越来越多的中小企业通过组成正式或非正式的联盟进行联合采购来降低采购价格.文章考虑了供应商提供线性数量折扣方案下多零售商联合采购的订货决策与费用分配问题.应用合作博弈理论,将数量折扣下多零售商联合采购的费用分配问题构造成联合采购博弈,证明了博弈满足次加性和平衡性,给出了一种属于博弈核心的费用分配方案,并用最大一致集分析了联盟的稳定性.     

外部市场存在替代产品的VMI系统研究

供应商管理用户库存(VMI)作为一种有效的补货机制,能对购买渠道的需求信息做出积极正确的反应.现在对VMI的研究往往集中于单个零售商和单个供应商组成的系统,不考虑VMI系统受市场上其他零售商或供应商的影响.假设市场上多个零售商出售相互之间可替代的产品,某个零售商与其供应商之间应用VMI系统.我们的研究主要有两方面:1)VMI系统是否有助于零售商和供应商组成的供应链在差异产品市场上获得更大的收益;2)供应商和零售商如何决策是否应用VMI系统。     

供应中断下零售商的最优定价和最优分批订购策略

考虑了由两个可靠性不同的供应商,一个零售商和一个竞争零售商组成的供应链系统,研究了以双垄断市场为背景,在供应中断条件下,建立了零售商的最优定价模型,给出了最优销售价格和分批订购策略.最后通过数值算例就零售商和竞争零售商价格对竞争零售商的采购成本在不中断和中断情形下做了比较.     

两层次广告博弈中供应商的一种批发价协调策略

研究了在包含一个供应商和两个零售商的供应链中的广告博弈协调问题.将该问题构造为一个两层次的博弈:供应商与零售商之间的Stackelberg博弈以及零售商之间的合作博弈.供应商作为整个供应链上的主导者,拥有产品批发价和零售价的决策权,而零售商则通过在当地市场上的广告促销投入来影响需求,进而影响整个供应链的收益.研究发现,供应商可以通过简单地设定适当的批发价来影响零售商的广告促销投入,从而使得整个供应链实现最大收益.     

供应链协调中供应商的价格歧视策略

分析了包含一个供应商和两个不同零售商的供应链网络的协调问题.将这一问题构建为一个两层次的博弈模型:零售商之间的非合作博弈以及供应商与零售商之间的Stackelberg博弈.博弈的均衡表明,通过简单的价格歧视,供应商就能够实现整个供应链网络的协调,而且价格歧视的水平与零售商之间的市场容量差异、产品需求的价格敏感系数以及产品的边际生产成本有关.在合理的参数范围内,市场容量更大的零售商所收取的零售价格较低,从供应商那里取货的成本也较低.这样的结论是比较符合现实情形的,这也就说明该模型为现实世界中的价格差异提供了另一种解释.此外,还分析了当供应商无法实施价格歧视时,由此导致的供应链的损失.     

Optimal solutions for the economic lot-sizing problem with multiple suppliers and cost structures

This paper considers a multi-supplier economic lot-sizing problem in which the retailer replenishes his inventory from several suppliers. Each supplier is characterized by one of three types of order cost structures: incremental quantity discount cost structure, multiple set-ups cost structure and all-unit quantity discount cost structure. The problem is challenging due to the mix of different cost structures. For all cases of the problem where each supplier is characterized by one of the first two cost structures, some optimality properties are proposed and optimal algorithms based on dynamic programming are designed. For the case where all suppliers are characterized by all-unit quantity discount cost structures, it is hard to design a polynomial time algorithm by the analyzed optimal properties. However, it is proved that one of its special cases can be solved in polynomial time.     

基于多种运输渠道的经济批量问题的多项式时间算法

为了集中管理, 降低成本, 增强竞争优势, 供应商通常只负责生产,而把产品的配送业务外包给某个配送中心, 由配送中心按照零售商的需求决定发货运输的方式和时间.这样供应商, 配送中心和零售商就构成了二级供应链系统.本文研究的是运输方式为不同参数的全单位数量折扣结构时, 二级供应链系统的经济批量问题.分析了最优解的性质,并对此问题的一种特殊情形给出一个多项式时间算法.     

带有可变库存费用和短缺的变质性物品的经济批量模型

传统的经济批量模型通常都假定物品的库存费用是固定不变的.放松了这个假定,通过考虑库存费用的两种可能变化情形即(A)库存费的变化率为存储时间的函数;(B)库存费的变化率为库存量的函数,并在需求线性依赖于库存水平的形式下,发展了两个变库存费的变质性物品的经济批量模型.在模型中允许短缺发生且假定短缺完全拖后,理论上证明了模型具有唯一的整体最优解,揭示了库存费的变化对库存系统最优订货策略的影响.     

Integrated Inventory Replenishment and Temporal Shipment Consolidation: A Comparison of Quantity-Based and Time-Based Models

In this paper we present two models for joint stock replenishment and shipment consolidation decisions which arise in the context of vendor managed inventory. Stock replenishment from suppliers or shipment to customers each incurs a lump-sum cost to the vendor. We assume the vendor uses the reorder point, lot-size policy to replenish stock and one of two schemes to dispatch shipment: the time-based and quantity-based consolidation schemes. Under the time-based (quantity-based) scheme, a shipment is dispatched periodically (when a certain quantity of outstanding demand is accumulated). The basic finding is that the quantity-based scheme can outperform the time-based counterpart while the reverse never occurs.     

满足多断点折扣费用函数的经济批量问题的多项式时间算法

在进货费用为全单位数量折扣函数的基础上,建立了一类有限时期内的经济批量问题.通过分析最优解的性质,设计了一个计算复杂性为O(T3+mT2)的动态规划算法,其中m为全单位数量折扣费用中的断点数,T为时期数.最后的算例进一步说明了该算法的有效性.     

A comparative study of modeling and solution approaches for the coordinated lot-size problem with dynamic demand

In the coordinated lot-size problem, a major setup cost is incurred when at least one member of a product family is produced and a minor setup cost for each different item produced. This research consolidates the various modeling and algorithmic approaches reported in the literature for the coordinated replenishment problem with deterministic dynamic demand. For the two most effective approaches, we conducted extensive computational experiments investigating the quality of the lower bound associated with the model’s linear programming relaxation and the computational efficiency of the algorithmic approaches when used to find heuristic and optimal solutions. Our findings indicate the superiority of the plant location type problem formulation over the traditional approach that views the problem as multiple single-item Wagner and Whitin problems that are coupled by major setup costs. Broader implications of the research suggest that other classes of deterministic dynamic demand lot-size problems may also be more effectively modeled and solved by adapting plant location type models and algorithms.     

Large-Scale Joint Price-Inventory Decision Problems, Under Resource Limitation and a Discrete Price Set

This article addresses a generalization of the capacitated lot-size problem (CLSP) as well as the profit maximization capacitated lot-size problem (PCLSP) considering joint price inventory decisions. This problem maximizes profit over a discrete set of prices subject to resource limitations. We propose a heuristic based on Lagrangian relaxation to resolve the problem, especially aiming for large scale cases. Results of experimentation exhibit the major importance of the capacity constraint. When this one is weak, our heuristic performs particularly well, moreover the numbers of possible prices does not really impact the results.     

Joint Price and Lot-Size Determination When Supplier Offers Incremental Quantity Discounts

This paper considers the joint pricing and the lot-size determination problem faced by a retailer when he purchases a product for which the supplier offers incremental quantity discounts. Two common demand functions are considered: (1) the constant price-elasticity function, and (2) the linear function. A procedure is provided for each case for calculating the optimal price and the lot-size.     

Heuristic Methods for the Multi-product Dynamic Lot Size Problem

Many heuristics exist for the single-item dynamic lot-size problem, for example, the Silver-Meal, the part period balancing and a simple variant of the part period balancing. The worst case performances of these heuristics have been shown to be zero, 1/3 and 1/2 respectively. These heuristics can be generalized to the dynamic version of the joint replenishment problem, that is, the multi-product dynamic lot-size problem. Such a generalization of the Silver-Meal heuristic has been shown to perform well on a set of test problems. This paper generalizes the part period balancing heuristic, and a simple variant of it to the multiproduct dynamic lot-size problem, and shows that the worst case performances of the generalized heuristics remain 1/3 and 1/2 respectively. An improved version of the generalized Silver-Meal heuristic is also given.     

Stochastic optimization models for a single-sink transportation problem

In this paper, we study a single-sink transportation problem in which the production capacity of the suppliers and the demand of the single customer are stochastic. Shipments are performed by capacitated vehicles, which have to be booked in advance, before the realization of the production capacity and the demand. Once the production capacity and the demand are revealed, there is an option to cancel some of the booked vehicles against a cancellation fee; if the quantity shipped from the suppliers using the booked vehicles is not enough to satisfy the demand, the residual quantity is purchased from an external company. The problem is to determine the number of vehicles to book in order to minimize the total cost. We formulate a two-stage and a multistage stochastic mixed integer linear programming models to solve this problem and test them on a real case provided by Italcementi, the primary Italian cement producer and the fifth largest cement producer in the world. We test the influence of different scenario-tree structures on the solutions of the problem, as well as sensitivity of the results with respect to the cancellation fee.