Bullwhip effect measure in a seasonal supply chain

In this study, the bullwhip effect in a seasonal supply chain was quantified by considering a two echelon supply chain which consists of one supplier and one retailer. The external demand occurring at the customer was assumed to follow a SARMA (1, 0) X (0, 1) _s scheme, a seasonal autoregressive-moving average process, while the retailer employed an base-stock policy to replenish their inventory. The demand forecast was performed with a SARMA (1, 0) X (0, 1) _s using the minimum mean-square error forecasting technique. In order to develop the bullwhip effect measure in a seasonal supply chain, the lead time demand forecast, forecast error, and the optimal inventory policy at the retailer were derived in sequence. The variance of order quantity based on these results was obtained. Then, various properties were derived by analyzing the bullwhip effect measure. Specifically, it was determined that the seasonal cycle plays an important role in bullwhip effect under a seasonal supply chain. The findings also point out that the replenishment lead time must be less than the seasonal cycle in order to reduce the bullwhip effect. Therefore, the lead time needs to be reduced through collaboration between the retailer and supplier.     

Commitment decisions with demand information updating and a capital‐constrained supplier

In this paper, we study a single two‐echelon supply chain with a capital‐constrained supplier (manufacturer) and a retailer. The supply chain faces a stochastic demand. As the production lead time is long, the market demand is updated during the supplier's production lead time. The supplier needs to determine the production quantity based on the original demand forecast, and the retailer needs to determine the time and quantity to order. The retailer can place an order before the supplier's production (preorder) or after the supplier's production (regular order). We prove the existence of optimal equilibrium solutions under both preorder and regular order strategies. We analytically investigate the order strategies for the supply chain agents under perfect and worthless market information updating. Moreover, we numerically analyze the impact of the information updating quality on the order strategy selection, and the effect of exogenous shocks on the supply chain agents.     

A study on inventory replenishment policies in a two-echelon supply chain system

Inventory control plays an important role in supply chain management. Properly controlled inventory can satisfy customers’ demands, smooth the production plans, and reduce the operation costs; yet failing to budget the inventory expenses may lead to serious consequences. The bullwhip effect, observed in many supply chain management cases, causes excessive inventory due to information distortion, i.e. the order amount is exaggerated while a minor demand variation occurs, and the information amplified dramatically as the supply chain moves to the upstream. In this paper, one of the main causes of bullwhip effect, order batching, is considered. A simplified two-echelon supply chain system, with one supplier and one retailer that can choose different replenishment policies, is used as a demonstration. Two types of inventory replenishment methods are considered: the traditional methods (the event-triggered and the time-triggered ordering policies), and the statistical process control (SPC) based replenishment method. The results show that the latter outperforms the traditional method in the categories of inventory variation, and in the number of backlog when the fill-rate of the prior model is set to be 99%. This research provides a different approach to inventory cost-down other than the common methods like: information sharing, order batch cutting, and lead time reduction. By choosing a suitable replenishment policy, the number of backorder and the cost of inventory can be reduced.     

Dynamic ordering and pricing for a perishable goods supply chain

The paper studies the combined problem of pricing and ordering for a perishable product supply chain with one supplier and one retailer in a finite horizon. The lifetime of the product is two periods and demand in each period is random and price-sensitive. In each period, the supplier determines first a wholesale price and then the retailer decides an order quantity and retail prices. We show that the optimal pricing strategy for the non-fresh product depends only on its inventory, and the optimal pricing strategy and the optimal order quantity for the fresh product depend only on the wholesale price and they have a constant relation. Moreover, the game between the retailer and the supplier for finite horizon is equivalent to a one period game with only one order. Thus, the optimal policies are identical at each period. For the additive and multiplicative demands, we further obtain equations to compute the optimal strategies. All of above results are extended into the infinite horizon case and longer lifetime products. Finally, a numerical analysis is given.     

基于批发价格事前和事后决策的供应链合作促销策略研究

针对单一供应商和单一零售商组成的二级供应链系统,构建了批发价格事前和事后决策下的合作促销模型,探讨了批发价格事前和事后决策对合作促销的影响,并求得Stackelber主从博弈下的均衡合作促销策略。研究结果表明,在批发价格事前决策且零售商努力影响需求、或批发价格事后决策且供应商努力影响需求的情形下,合作促销均不是一个有效的激励策略;在批发价格事前决策且供应商努力影响需求的情形下,只有当促销努力成本共担系数小于一定的阈值时,合作促销才是一个有效的激励策略;在批发价格事后决策且零售商努力影响需求的情形下,合作促销始终是有效的激励策略。最后通过算例分析验证了上述结论的有效性。     

A decision rule for coordination of inventory and transportation in a two-stage supply chain with alternative supply sources

This paper deals with a two-stage supply chain that consists of two distribution centers and two retailers. Each member of the supply chain uses a (Q,R) inventory policy, and incurs standard inventory holding and backlog costs, as well as ordering and transportation costs. The distribution centers replenish their inventory from an outside supplier, and the retailers replenish inventory from one of the two distribution centers. When a retailer is ready to replenish its inventory that retailer must decide whether it should replenish from the first or second distribution center. We develop a decision rule that minimizes the total expected cost associated with all outstanding orders at the time of order placement; the retailers then repeatedly use this decision rule as a heuristic. A simulation study which compares the proposed policy to three traditional ordering policies illustrates how the proposed policy performs under different conditions. The numerical analysis shows that, over a large set of scenarios, the proposed policy outperforms the other three policies on average.     

Coordination-based inventory management for deteriorating items in a two-echelon supply chain with profit sharing

This study develops a model for inventory management consisting of a two-echelon supply chain (SC) with profit sharing and deteriorating items. The retailer and the supplier act as the leader and follower, in which the supplier faces a huge setup cost and economic order quantity ordering strategy. The market demand is affected by the sale price of the product, and the inventory has a deterioration rate following a Weibull distribution. The retailer executes three profit-sharing mechanisms to motivate the supplier to participate in SC optimisation and to extend the life cycle of the product. A search algorithm is developed to determine the solutions as using the profit-sharing mechanisms. The outcomes from numerical experiments demonstrate the profitability of the proposed model.     

Analysis on the effects of stock sharing on supply chain

Considering a two-period, two-part supply chain consisting of one supplier and multi-retailers, this paper studies the effects of stock sharing among retailers on the supply chain. By establishing analysis model and using simulation method, the effects of stock sharing mode and also the traditional mode without stock sharing on retailer, supplier and the whole supply chain’s performance are analyzed. The research results show that when supplier is in a dominant position, although only under certain conditions the stock sharing can stimulate retailer to increase order volume and make supplier to gain a better profit, it always make the profitability of retailer and supplier better than in the traditional mode. When supplier is in a dominant position, stock sharing can always stimulate retailer to increase their order volume, and the profitability of the retailer, supplier and the whole supply chain is always better than the traditional mode situation without stock sharing.     

带有订单转保理的供应链金融的收益共享博弈模型

当作为供应商的中小企业出现了严重的财务困境问题时,急需有效融资工具和创新管理模式加以解决.订单转保理可以令资质良好的零售商为资金短缺的供应商提供融资担保,有效解决供应商的订单减少和融资难的问题.然而,分散决策的订单转保理融资模式,使得做担保的零售商的收益降低,不能明显改善供应链效率.针对此问题,研究订单转保理模式下的供应链协调模型,并重点研究由供应商与零售商组成的二级供应链的订单转保理收益共享模型.研究发现:收益共享决策模型供应链总收益小于集中决策供应链总收益,大于分散决策的供应链总收益,表明供应链成员相互合作程度越高,越有利于供应链发展,从而表明协调在供应链中发挥重要作用.然而,集中决策模型只能得到供应链最优总收益,无法得到供应商和零售商的最优收益.收益共享模型不仅能够提高产品订货量,降低产品批发价格,增加供应商和零售商的收益,而且通过最优的收益共享系数可以得到供应商和零售商的最优收益.收益共享机制能够为供应商和零售商共赢协调发展提供新的运作管理模式.     

Contract analysis: A performance measures and profit evaluation within two-echelon supply chains

Coordination is regarded as key in managing dependencies between distinctive members of a supply chain through the benefits of coordination mechanisms. Such coordination mechanisms are contracts, implemented to increase total supply chain profit, reduce costs and share risk among supply chain members. However, by contract implementation the retailer is constrained in his purchase by bearing the entire risk of holding the inventory (wholesale price contract) or by limited risk allocated to the supplier (buyback, revenue sharing and quantity flexibility contracts). By implementing an advanced purchase system the risk of inventory is fairly divided between the supplier and the retailer. In order to observe inventory implications on the supply chain bottom line, this article is directed towards the evaluation of performance measures and supply chain profit behavior under buyback, revenue sharing, quantity flexibility and advanced purchase discount contracts versus no coordination and wholesale price systems.     

考虑风险规避与质量和服务水平的VMI供应链期权协调策略

针对一个考虑风险规避供应商与质量和服务水平的二级VMI供应链,应用条件风险价值(CVaR)准则刻画供应商的风险规避行为,提出由期权和成本分担构成的组合契约,构建以零售商为主导的Stackelberg博弈模型,探讨供应链协调策略以及风险规避对供应链协调和利润分配的影响.研究表明,供应商的最优生产量随着其风险规避程度的增加而减小,但最优质量和服务水平与风险规避程度无关;当且仅当供应商风险规避程度较低时供应链才能实现协调,且供应商风险规避程度是影响供应链契约设计和利润分配的关键因素.     

The benefit of VMI strategies in a stochastic multi-product serial two echelon system

We consider a multi-product serial two echelon inventory system with stochastic demand. Inventories at the downstream location are replenished periodically using an automatic ordering system. Under vendor managed inventory strategies the upstream stage is allowed to adapt these orders in order to benefit from economies of scale. We propose three different VMI strategies, aiming to reduce the order picking cost at the upstream location and the transportation costs resulting in reduced total supply chain costs. In a detailed numerical study the VMI strategies are compared with a retailer managed inventory strategy for two different demand models suitable for slow moving products. It is shown that if inventory holding costs are low, compared to handling and transportation costs, efficiencies at the warehouse are improved and total supply chain costs are reduced.     

需求不确定性对混合条件风险价值约束供应链系统的影响

运用随机占优研究风险偏好和需求不确定性对混合条件风险价值约束供应链系统的影响.证明在批发价和收益共享契约下零售商的最优订货量和利润随风险偏好系数的增加而减小;只有在零售商为风险追求型时,批发价契约才能实现供应链协调;无论零售商的风险偏好如何,收益共享契约都能实现供应链协调.在收益共享契约下,随机大需求将导致零售商获得较高的最优利润;当零售商为风险中性或风险厌恶时,其最优利润随需求可变性的增加而减少.     

Supply chain financing with advance selling under disruption

We study a financing problem in a supply chain (SC) consisting of one supplier and one buyer under supply disruption. The supplier could face a disruption at its end which could effectively reduce its yield in case of disruption, thereby resulting in supply yield uncertainty. The retailer can finance the supplier using advance selling that can help mitigate the impact of disruption. We model this problem as a Stackelberg game, where the supplier as the leader announces the wholesale price and the retailer responds by deciding its optimal order quantity given stochastic demand and an exogenous fixed retail price. The supplier then commences production and a disruption can happen with a known probability. We assume that under disruption the quantity delivered is a fraction of the initial quantity ordered by the retailer. The retailer loses any unmet demand. We analyze three different scenarios of the Stackelberg game, namely no advance selling with disruption, advance selling without disruption, and advance selling with disruption. Our results indicate that advance selling can be used to mitigate the impact of supply disruption and at the same time could lead to an increase in the overall SC profit.     

Determinant on RFID technology investment for dominant retailer subject to inventory misplacement

Radio‐frequency identification (RFID) technology has been publicized as an effective way to solve the problem of inventory misplacement in academic research as well as in the user industries. In this paper, we consider a supply chain that consists of one supplier and one retailer where the retailer is the Stackelberg leader and makes the decisions first. The consignment contract is provided such that the supplier determines the order quantity, instead of the retailer. A Non‐RFID case, a supplier investing in RFID, and a retailer investing in RFID cases are analyzed and compared. By assuming an iso‐elastic demand function and the corresponding random factor follows uniform distribution, it is intriguing to find that both supplier and retailer have the incentive to take charge of the RFID tag cost, which is not revealed in previous research. Therefore, a case of joint investment in RFID technology is formulated to find out that there are upper and lower threshold values of RFID tag cost sharing rate; that is, if the tag cost sharing rate exceeds the upper value, it is beneficial for the supplier to invest in RFID; if the tag cost sharing rate is smaller than the lower value, it is beneficial for the retailer to invest in RFID; if the tag cost sharing rate is somewhere between these two values, both supplier and retailer are better‐off. Additionally, the end customer will be better‐off if the retailer invests in RFID.     

模糊需求下的闭环供应链协调机制研究

研究一个由制造商和零售商在模糊需求环境下的两级闭环供应链的协调机制问题。将市场需求视为模糊变量,建立模糊截集理论下的集中决策模型和收益-费用共享契约模型,给出模型中的最优策略,并以三角形模糊变量为例,对模型进行优化。通过数值算例对模型中的参数进行求解,并对分析结论进行验证。研究结果表明,在模糊需求环境下的闭环供应链中,零售商的最优订购量在模糊需求中心点的左、右浮动,并随着零售价格的提高而增加,通过改变收益-费用系数可以实现供应链成员之间的完美协调。     

Coordinating a two-supplier and one-retailer supply chain with forecast updating

We consider the component-purchasing problem for a supply chain consisting of one retailer and two complementary suppliers with different lead-times. The retailer purchases a specific component from each supplier for assembling into a fashionable product. After ordering from the long-lead-time supplier (Supplier 1) and before ordering from the short-lead-time supplier (Supplier 2), the retailer can update its demand forecast for the product. The retailer can partially cancel its order from Supplier 1 after forecast updating. By formulating the problem as a dynamic optimization problem, we explore the measures that can be deployed to coordinate the retailer’s ordering decisions with forecast updating. We analytically show that the supply chain can be coordinated if both suppliers offer a returns policy and Supplier 1 charges an order-cancelation penalty to the retailer. We find that the coordination mechanism is independent of demand distribution and the forecast updating process. We further show that it is easier for the suppliers to coordinate the supply chain if market observation indicates the future market demand is sufficiently large. We also study the case where demand is price-dependent and propose a generalized revenue-sharing contract to coordinate the supply chain. We discuss the academic and managerial implications of the theoretical findings.     

基于零售商资金约束供应链采用RFID技术的决策及融资分析

为研究零售商存在资金约束和库存错放时,供应链成员采用无线射频识别(radio frequency identification,RFID)技术及融资决策的均衡问题,以单制造商和单资金约束零售商组成的两级供应链为研究对象,基于报童模型构建供应链成员采用RFID技术前后零售商是否融资4种情景下的收益模型,求解出相应的最优解并探讨供应链成员RFID采用决策与零售商的融资策略.研究发现:当零售商的自有资金适中时,供应链成员采用RFID技术一定程度上能够缓解零售商的资金约束;零售商选择融资时,供应链及其成员能够承担更高的RFID成本;零售商分摊RFID固定成本的比例对制造商、零售商和供应链能够承担的RFID标签成本阈值有决定性的影响.     

An integrated retail space allocation and lot sizing models under vendor managed inventory and consignment stock arrangements

In this paper, we develop integrated retail shelf space allocation and inventory models for a single item with a stock dependent demand. The integrated models are developed for a supply chain operating under vendor-managed inventory (VMI) and consignment stock (CS) agreement. More precisely, the supplier is responsible for initiating orders on behalf of the retailer and decides about the size of each order, the quantity to be displayed on the shelves, and the reorder point. In addition, the supplier owns the stock at the retailer’s premises until it is sold. We develop mathematical models to assess the benefits accrued by both parties as a result of the adoption of VMI–CS partnership. Results from the numerical experimental study show that such partnership is more attractive to all supply chain members when the retailer provides a flexible display capacity. Moreover, the supplier can use his/her selling price and the maximum allocated shelf space as negotiation means to benefit from the partnership.     

Contracts choice for supply chain under inflation

Inflation causes an increase in the retail price and a decrease in the market demand, both arise from the problem of seasonal product management and occur during the long production lead time. As an effective tool for hedging against the risks, option contracts, including call, put, and bidirectional option contracts, have been proved to benefit two members in a one‐supplier and one‐retailer supply chain under inflation. The aim of this paper is to examine the effect of different option contacts on the decisions and performances for both the supplier and the retailer under inflation. Our results suggest that the retailer prefers adopting portfolio contracts with bidirectional options under inflation, whereas the supplier is inclined to provide call option contracts under inflation. Our study also reveals that call option contracts are implemented ultimately by the supply chain under inflation because of the supplier's market dominant position.