The impact of information sharing in a two-level supply chain with multiple retailers

Information sharing is an important component of cooperation in supply chain management. This paper presents a study to evaluate the impact of information sharing on inventory and expected cost in a two-level supply chain with multiple retailers. Three levels of information sharing are given and the optimal inventory policy under each level is derived. We show that both the inventory level and expected cost of the manufacturer decrease with an increase in the level of information sharing.     

考虑供应链渠道冲突的零售商自有品牌产品定价方法

自有品牌产品定价是电子商务环境下零售商实施渠道管理的关键因素,其合理与否直接影响到零售商利润和供应链稳定.鉴于此,针对存在供应链渠道冲突的零售商自有品牌定价问题,从协调的角度,利用对偶理论与优化模型,构建了基于最小协调成本的零售商自有品牌产品定价决策方法,并利用其探讨协调的经济意义,求解零售商自有品牌产品最优定价.结果表明,所构建的模型能够有效描述和解决零售商自有品牌产品定价问题,并在一定程度上消除供应链渠道冲突,保证供应商和零售商长期有效合作和供应链可持续发展.     

Supply chain scheduling: Sequence coordination

A critical issue in supply chain management is coordinating the decisions made by decision makers at different stages, for example a supplier and one or several manufacturers. We model this issue by assuming that both the supplier and each manufacturer have an ideal schedule, determined by their own costs and constraints. An interchange cost is incurred by the supplier or a manufacturer whenever the relative order of two jobs in its actual schedule is different from that in its ideal schedule. An intermediate storage buffer is available to resequence the jobs between the two stages. We consider the problems of finding an optimal supplier's schedule, an optimal manufacturer's schedule, and optimal schedules for both. The objective functions we consider are the minimization of total interchange cost, and of total interchange plus buffer storage cost. We describe efficient algorithms for all the supplier's and manufacturers’ problems, as well as for a special case of the joint scheduling problem. The running time of these algorithms is polynomial in both the number of jobs and the number of manufacturers. Finally, we identify conditions under which cooperation between the supplier and a manufacturer reduces their total cost.     

考虑释放时间的单机JIT调度问题

本文主要研究二级供应链中的生产-库存-直接配送协同调度问题,其中存在一个制造商和多个零售商, 制造商根据订单进行生产, 然后将产品配送给零售商。该类问题可以抽象为考虑释放时间的单机JIT调度问题。借助于禁忌搜索算法, 本文提出了求解问题的CTA-TS算法, 并通过大量的实验数据与已有算法进行比较,说明了本文提出算法的有效性。     

A queuing approach for inventory planning with batch ordering in multi-echelon supply chains

This paper presents stylized models for conducting performance analysis of the manufacturing supply chain network (SCN) in a stochastic setting for batch ordering. We use queueing models to capture the behavior of SCN. The analysis is clubbed with an inventory optimization model, which can be used for designing inventory policies . In the first case, we model one manufacturer with one warehouse, which supplies to various retailers. We determine the optimal inventory level at the warehouse that minimizes total expected cost of carrying inventory, back order cost associated with serving orders in the backlog queue, and ordering cost. In the second model we impose service level constraint in terms of fill rate (probability an order is filled from stock at warehouse), assuming that customers do not balk from the system. We present several numerical examples to illustrate the model and to illustrate its various features. In the third case, we extend the model to a three-echelon inventory model which explicitly considers the logistics process.     

JIT环境下三级供应链供需协调模型研究

模型以整个供应链成本最低为目标,在JIT环境下通过对原材料供应商、制造商和零售商等各阶段库存模型以及其他相关成本的研究,得到供应链的最优物料补充策略,制造商的最优生产策略以及产成品运输策略。供应链结构包括一个制造商,多个原材料供应商和零售商。研究表明,通过有效的加强整条供应链的协作,能够有效降低供应链的总成本。     

Pricing in a supply chain for auction bidding under information asymmetry

We examine a supply chain in which a manufacturer participates in a sealed-bid lowest price procurement auction through a distributor. This form of supply chain is common when a manufacturer is active in an overseas market without establishing a local subsidiary. To gain a strategic advantage in the division of profit, the manufacturer and distributor may intentionally conceal information about the underlying cost distribution of the competition. In this environment of information asymmetry, we determine the equilibrium mark-up, the ex-ante expected mark-up and expected profit of the manufacturer and the equilibrium bid of the distributor. In unilateral communication, we demonstrate the informed agent’s advantage resulting to higher mark-up. Under information sharing, we show that profit is equally shared among the supply chain partners and we explicitly derive the mark-up when the underlying cost distribution is uniform in [0, 1]. The model and findings are illustrated by a numerical example.     

一种带有生产费用扰动的供应链协调问题

本文研究了一个生产两个竞争零售商的供应链在生产费用发生扰动下的协调问题．生产费用发生扰动后，零售商的投资额与生产商的生产数量都会和原计划不同．研究发现批发价加投资补贴率的合同可以协调扰动后的供应链，通过调整批发价和补贴率，可使供应链总的利润在生产商与两个零售商之间分配，并用数值模拟分析了所得结果的合理性．     

时变需求等量进货情形下集成供应链生产订货策略研究

构建了一个包含原料采购、生产和销售过程的集成供应链模型,研究了由原料、生产商和销售商产品构成的三层库存系统的生产订货问题。在有限的规划期内,销售商每次进货量相同,生产商按照EOQ模型采购原材料。以最小化供应链系统的总运营成本为目标,构建一个混合整数非线性规划模型,寻找销售商最优订货方案和生产商最佳生产策略。首先利用网络优化方法求解生产商的最优生产计划,其次利用定界穷举法寻求销售商最优的订货周期,给出了具体的计算方法和Matlab程序。通过算例分析验证了算法的有效性,并研究了各参数对最小费用及最优解的影响。     

一种随机需求下的供应链激励机制

研究了在随机需求条件下，供应链中用价格折扣策略协调供需双方利益的问题。考虑随机性需求有可能造成分销商的库存积压，本提出了生产商给予分销商的积压商品价格折扣的策略，分析了其激励机制，给出了最优价格折扣的模型和算法。最后用数值方法验证了这种价格折扣策略能够给生产商和分销商带来利益改善，而且需求波动越大，该策略的协调效果越好。     

A model of JIT make-to-stock inventory with stochastic demand

We consider a firm that manages its internal manufacturing operations according to a just-in-time (JIT) system but maintains an inventory of finished goods as a buffer against random demands from external customers. We formulate a model in which finished goods are replenished by a small fixed quantity each time period. In the interest of schedule stability, the size of the replenishment quantity must remain fixed for a predetermined interval of time periods. We analyse the single-interval problem in depth, showing how to compute a cost-minimising value of the replenishment quantity for a given interval length, and characterising the optimal cost, inventory levels and service as functions of the interval length and initial inventory. The model displays significant cost and service penalties for schedule stability. A dynamic version of the problem is also formulated, and shown to be convex in nature with relatively easily computed optima.     

An integrated production and inventory model to dampen upstream demand variability in the supply chain

We consider a two-echelon supply chain: a single retailer holds a finished goods inventory to meet an i.i.d. customer demand, and a single manufacturer produces the retailer’s replenishment orders on a make-to-order basis. In this setting the retailer’s order decision has a direct impact on the manufacturer’s production. It is a well known phenomenon that inventory control policies at the retailer level often propagate customer demand variability towards the manufacturer, sometimes even in an amplified form (known as the bullwhip effect). The manufacturer, however, prefers to smooth production, and thus he prefers a smooth order pattern from the retailer. At first sight a decrease in order variability comes at the cost of an increased variance of the retailer’s inventory levels, inflating the retailer’s safety stock requirements. However, integrating the impact of the retailer’s order decision on the manufacturer’s production leads to new insights. A smooth order pattern generates shorter and less variable (production/replenishment) lead times, introducing a compensating effect on the retailer’s safety stock. We show that by including the impact of the order decision on lead times, the order pattern can be smoothed to a considerable extent without increasing stock levels. This leads to a situation where both parties are better off.     

Demand disruption and coordination of the supply chain with a dominant retailer

This paper develops two coordination models of a supply chain consisting of one manufacturer, one dominant retailer and multiple fringe retailers to investigate how to coordinate the supply chain after demand disruption. We consider two coordination schedules, linear quantity discount schedule and Groves wholesale price schedule. We find that, under the linear quantity discount schedule, the manufacturer only needs to adjust the maximum variable wholesale price after demand disruption. For each case of the disrupted amount of demand, the higher the market share of the dominant retailer, the lower its average wholesale price and the subsidy will be under the linear quantity discount schedule, while the higher its fraction of the supply chain’s profit will be under Groves wholesale price schedule. When the increased amount of demand is very large and production cost is sufficiently low, linear quantity discount schedule is better for the manufacturer. However, when the production cost is sufficiently large, Groves wholesale price schedule is always better. We also find that the disrupted amount of demand largely affects the allocation of the supply chain’s profit.     

Modelling the benefits of information sharing-based partnerships in a two-level supply chain

This paper presents a study aimed at quantifying the benefits of information sharing-based supply chain partnerships. We derive the optimal inventory policies for the manufacturer and the retailer in a two-level decentralized supply chain under different information sharing scenarios. We show that increasing information sharing among the members in a decentralized supply chain will lead to Pareto improvement in the performance of the entire chain. Specifically, the manufacturer can obtain benefits in terms of reductions in inventory levels and cost savings.     

基于时间的供应链物流运作能力计划模型研究

本文考察了在基于时间的多阶供应链环境下的物流运作能力计划,主要的系统成本是物流要素能力固定成本和库存成本.为了决定最优的稳定周期性的物流运作能力计划,提出了一般性的整数非线性规划公式.强调了在这样的系统运作中的开始时间的关键作用,报告了在确保在任何阶段没有缺货条件下的物流能力决策的一些有价值的结论.     

不同博弈框架下多竞争零售商的双渠道供应链定价决策研究

在Bertrand竞争、Stackelberg竞争及集中决策下,研究由单制造商与多竞争零售商组成的双渠道供应链的定价决策问题。运用两阶段优化技术、博弈论及矩阵论,讨论了多竞争零售商与单制造商在价格方面相互竞争的问题,给出不同市场竞争模式及集中决策下供应链成员的博弈均衡解。对比不同博弈框架及集中决策下供应链成员的定价决策,通过数值实验分析了价格敏感度及零售商个数对最优定价决策和最大利润影响,给出一些管理学理论与见解,为双渠道供应链中各成员的管理者制定最优决策提供理论支持。     

Optimal production and inventory rationing policies with selective-information sharing and two demand classes

This paper studies the impact of partner selection on the value of information sharing in a distribution system with one capacitated make-to-stock manufacturer and two retailers. When the high priority retailer with a higher shortfall cost is the sole partner, in the case that the low priority one places an order, the manufacturer allocates inventory more accurately according to more predictable orders from the high priority retailer. When only the low priority retailer shares information, the manufacturer is better informed about orders from this retailer, which shall trigger rationing decisions. Such intriguing differences in utilizing information from two prioritized retailers further induce different interactions between production and rationing policies and form two distinctive but closely related selective-information sharing systems. We characterize the manufacturer’s optimal production and rationing policies under both systems. Through a numerical study, we emphasize the effectiveness of partnering with the high priority retailer. When the manufacturer can establish information sharing links with only one retailer, such a choice usually brings more benefits despite differences in order sizes and/or demand rates of the two retailers. When a selective-information sharing system is the pilot run to full-information sharing, we find that the value of information throughout the implementation process often exhibits second-mover advantage and such a choice also helps the manufacturer create a more balanced return pattern. Finally, we illustrate that the cost-effectiveness of inventory rationing can be significant and optimally rationing inventory is the prerequisite for the superior of the selective-information sharing system with the high priority retailer.     

碳交易规制下信息不对称供应链的减排和低碳推广博弈研究

论文在碳交易规制下,研究单一制造商和双零售商组成的供应链减排与低碳推广决策以及零售商对制造商的成本信息分享问题,分析了零售商对制造商分享成本信息的条件,及不同情形下的制造商减排和零售商低碳推广策略。研究发现:零售商的最优低碳推广水平只与自身相关参数有关,零售商只有在自身低碳推广效率足够高时才会与制造商分享信息;制造商最优减排量随消费者低碳意识、碳交易价格、零售商低碳推广效率及其不确定性增大而提高,随零售商之间竞争程度提高而降低;无论零售商是否对制造商分享成本信息,供应链成员的最优利润随零售商之间竞争程度提高而增加,随消费者低碳意识、碳交易价格提高而提高;零售商低碳推广效率的不确定性越大则制造商的最优利润越低,零售商的最优利润越高;仅一家零售商分享成本信息时,制造商无法通过转移支付使另一家零售商与其分享信息。     

Nash game model for optimizing market strategies,configuration of platform products in a Vendor Managed Inventory (VMI) supply chain for a product family

This paper discusses how a manufacturer and its retailers interact with each other to optimize their product marketing strategies, platform product configuration and inventory policies in a VMI (Vendor Managed Inventory) supply chain. The manufacturer procures raw materials from multiple suppliers to produce a family of products sold to multiple retailers. Multiple types of products are substitutable each other to end customers. The manufacturer makes its decision on raw materials’ procurement, platform product configuration, product replenishment policies to retailers with VMI, price discount rate, and advertising investment to maximize its profit. Retailers in turn consider the optimal local advertising investments and retail prices to maximize their profits. This problem is modeled as a dual simultaneous non-cooperative game (as a dual Nash game) model with two sub-games. One is between the retailers serving in competing retail markets and the other is between the manufacturer and the retailers. This paper combines analytical, iterative and GA (genetic algorithm) methods to develop a game solution algorithm to find the Nash equilibrium. A numerical example is conducted to test the proposed model and algorithm, and gain managerial implications.     

Managing an integrated production inventory system with information on the production and demand status and multiple non-unitary demand classes

In this paper, we study a system consisting of a manufacturer or supplier serving several retailers or clients. The manufacturer produces a standard product in a make-to-stock fashion in anticipation of orders emanating from n retailers with different contractual agreements hence ranked/prioritized according to their importance. Orders from the retailers are non-unitary and have sizes that follow a discrete distribution. The total production time is assumed to follow a k₀-Erlang distribution. Order inter-arrival time for class l demand is assumed to follow a k_l-Erlang distribution. Work-in-process as well as the finished product incur a, per unit per unit of time, carrying cost. Unsatisfied units from an order from a particular demand class are assumed lost and incur a class specific lost sale cost. The objective is to determine the optimal production and inventory allocation policies so as to minimize the expected total (discounted or average) cost. We formulate the problem as a Markov decision process and show that the optimal production policy is of the base-stock type with base-stock levels non-decreasing in the demand stages. We also show that the optimal inventory allocation policy is a rationing policy with rationing levels non-decreasing in the demand stages. We also study several important special cases and provide, through numerical experiments, managerial insights including the effect of the different sources of variability on the operating cost and the benefits of such contracts as Vendor Managed Inventory or Collaborative Planning, Forecasting, and Replenishment. Also, we show that a heuristic that ignores the dependence of the base-stock and rationing levels on the demands stages can perform very poorly compared to the optimal policy.