基于收益共享的供应链中断协调研究

本文假定市场需求不确定和供给存在中断危机，同时考虑订货过剩损失和缺货成本，研究了由零售商、主供应商和备份供应商组成的供应链网络，构建了收益共享合同协调模型，通过相关参数的设定达到供应链协调。供应链协调时的供货量及整体利润均大于分散模型；备份供应商的供货量及利润随着中断危机的增大而增加，零售商利润也随之增加。     

Optimal economic ordering policy with deteriorating items under different supplier trade credits for finite horizon case

This paper develops and solves a general finite horizon trade credit economic ordering policy for an inventory model with deteriorating items under inflation and time value of money when shortages are not allowed. The time horizon is divided into different cycles each of which has its own demand rate and its own trade credit period offered from the supplier to his retailer so that the retailer should pay his supplier before or after the end of the permissible trade credit of that cycle. Up to the end of the trade credit of a cycle, the retailer is free of charge, but he is charged on an interest for those items not being sold before this end. The retailer can also earn the interest of the money from the generated sales revenue in any cycle by depositing such revenue into an interest bearing account. The objective of the retailer is then to minimize his net total relevant costs. A closed form of this net total cost is derived and the resulting model is solved. Then rigorous mathematical methods are used to show that, under some seemingly possible conditions, there exist a unique vector of the relevant decision variables that solve the underlying inventory system. A numerical example which shows the applicability of the theoretical results is given.     

Retailer policy, uncertainty reduction, and supply chain performance

We investigate how the retailer’s inventory policy affects the total cost of a serial supply chain. When the retailer uses the locally optimal (s,S) policy, there is randomness in order time and order quantity to the supplier whereas the supplier sees randomness only in order quantity for the suboptimal (R,T) policy and only in order time for another suboptimal (Q,r) policy. Using an extensive computational study, we find that the suboptimal policies perform better from the total supply chain perspective. The benefit of policy changes is magnified when the retailer costs are low, when the supplier costs are high, and when there is information sharing.     

Streamlining inventory flows with time discounts to improve the profits of a decentralized supply chain

We consider a decentralized supply chain, whereby a supplier sells a product to a group of independent buyers, and develop a strategy for the supplier to offer an all-units price discount or cash rebate for orders that are synchronized with its replenishments. As synchronized orders can be met with inventory directly from receiving to shipping without warehousing, the proposed strategy streamlines system inventory flows to minimize inventory and, hence, the related costs. On the other hand, by increasing the replenishment interval of the supplier, the proposed strategy is able to induce buyers to order in large quantities and hence achieve the objectives of quantity discounts. We show that the proposed strategy can achieve nearly optimal (minimum) system cost, and is much more effective than the existing coordination strategies for decentralized supply chains in the literature.     

基于利他行为下的闭环供应链决策研究

随着行为运营管理的发展,利他、公平、信任等行为得到广泛的关注。文章构建一个由供应商和零售商的闭环供应链,供应商负责旧产品回收再加工。将利他行为引入到供应链中,研究利他属性对供应链决策的影响。研究发现,在该模型的供应链中,供应商的利他属性,对于供应链的回收率、零售商的利润、供应商的效用、供应链的整体利润都是有益的。而零售商的利他行为,有利也有弊,带来的效益是局部的。然后通过数值分析对结论作出解释和说明。     

政府补贴下的三级低碳供应链减排博弈研究

本文分别构建了政府补贴下，供应链上企业单独减排、供应商对制造商碳减排成本进行分担、供应商和零售商均对制造商碳减排成本进行分担3种减排模型，求解得到不同减排模式下，包括成本分担率和单位减排量在内的供应链最优决策。研究发现，政府补贴率的提升反而使成本分担率降低。通过博弈分析及算例验证得出：在供应链上三方企业联合减排下，即供应商和零售商都对制造商的碳减排研发提供资金支持时，单位产品的减排量及各企业利润达到最大，仅供应商对制造商碳减排成本分担时次之， 供应链上企业单独减排时最小， 但仅供应商一方对制造商的碳减排成本进行分担时的成本分担率，比其与零售商同时分担时的要大。这些结论为政府确立合适的补贴方案及供应链上企业减排策略的制定提供了理论依据。     

A vendor managed inventory supply chain with deteriorating raw materials and products

Fast deteriorating raw materials such as raw milk, fruit and vegetables are commonly used to produce slowly deteriorating finished products such as milk powders, cheeses, and pastas. This paper studies a Vendor Managed Inventory (VMI) type supply chain where the manufacturing vendor decides how to manage the system-wide inventories of its fast deteriorating raw material and its slowly deteriorating product. The decision variables are a common replenishment cycle of the product and the replenishment frequency of the raw material. We assume the deteriorating rates are known constants and every retailer's demand is deterministic. We develop an integrated model to calculate the total inventory and deterioration cost for such a system. We prove the convexity of the cost functions, and based on this a golden search algorithm is developed to find the optimal solution of the model. Our numerical results show that the deteriorating rate of the product may increase the total cost by more than 40% compared to the zero-deteriorating rate, while the deteriorating raw material has less impact on the total cost (commonly less than 5% in our numerical examples). This indicates that more attention should be paid to the product than the raw material. Further, an increase in the number of retailers can make the replenishment frequency of the raw material increase significantly but the common replenishment cycle of the product decreases a little. This indicates that adding a new retailer would not be felt strongly by the other retailers but would be felt by the supplier of the raw material.     

零售商的风险规避特性和公平偏好对绿色供应链运作的影响

针对市场需求的不确定性，本文通过建立风险规避型零售商与风险中性供应商的Stackelberg博弈模型，供应商为主导者，综合考虑零售商风险规避特性和公平偏好心理对该供应链运作产生的影响。研究发现，当风险规避型零售商不具有公平意识时，零售商的风险规避程度与供应商的批发价、绿色创新投入水平以及供应商和供应链整体的效用正相关；供应商的绿色成本系数的大小可影响风险规避程度对产品售价以及零售商效用的影响。当风险规避型零售商具有公平偏好时，零售商的公平偏好负向影响产品售价、批发价以及供应商绿色投入水平和供应商效用；零售商公平偏好对零售商以及供应链效用产生的影响受到零售商风险规避程度的影响。     

Optimal inventory policy with noninstantaneous receipt under trade credit

In the last two decades, the models for inventory replenishment policies under trade credit have been widely studied by several researchers. However, the extant papers only consider the effects of permissible delay in payments in the inventory systems. In some situations, the supplier also may offer a cash discount to encourage retailer to pay for his purchases quickly. On the other hand, an inventory model with instantaneous receipt is not a common feature in actual practice. For generality, this study develops an inventory model with noninstantaneous receipt under trade credit, in which the supplier provides not only a permissible delay but also a cash discount to the retailer. We then characterize the optimal solution and provide an easy-to-use criterion to find the optimal order strategies. Finally, several numerical examples are presented to illustrate the theoretical results.     

Inter-temporal inventory competition and the effects of capacity constraints

This paper addresses an intertemporal inventory competition between a supplier (a provider, manufacturer) and a retailer engaged in a supply chain. The paper's focus is on the effect of capacity constraints on both parties when demands are seasonal. The paper provides a comparative study of two solution approaches, one is based on supply chain competition and the other is based on system wide optimization. Our results demonstrate that with dynamic inventory competition, the retailer reduces inventory costs by reducing the response period to higher demands while increasing the supply requests compared to the system-wide optimal approach. As a result, the supplier's inventory costs increase. An example illustrating these particular facets of the problem and its application is presented and discussed in light of the supplier and the retailer coordinating policies.     

Replenish-up-to inventory control policy with random replenishment intervals

The multi period inventory problems have been studied under two main assumptions. Continuous review assumption where an order can be made at any time depending on inventory position and periodic review assumption where an order can be initiated only at discrete time epochs. In this study, we analyze a multi period inventory problem that falls under neither of these two assumptions. In the case we consider, there are periodic replenishments but the replenishment intervals are taken to be i.i.d. random variables. This setting represents the real life cases where a supplier visits a retailer with random inter arrival times and the retailer replenishes his inventories based on a replenish-up-to-level inventory control policy. We also assume that only a certain fraction of unmet demand is backordered and the rest of it is lost.In this setting under general distribution between replenishment epochs, we show the concavity of the expected profit function and give the condition that must hold for the optimal replenish-up-to-level. We also present the specific solutions and analysis under two different distributions, namely, uniform and exponential distributions, together with some numerical examples.     

Inventory control in a two-level supply chain with risk pooling effect

We consider an inventory control problem in a supply chain consisting of a single supplier, with a central distribution center (CDC) and multiple regional warehouses, and multiple retailers. We focus on the problem of selecting warehouses to be used among a set of candidate warehouses, assigning each retailer to one of the selected warehouses and determining replenishment plans for the warehouses and the retailers. For the problem with the objective of minimizing the sum of warehouse operation costs, inventory holding costs at the warehouses and the retailers, and transportation costs from the CDC to warehouses as well as from warehouses to retailers, we present a non-linear mixed integer programming model and develop a heuristic algorithm based on Lagrangian relaxation and subgradient optimization methods. A series of computational experiments on randomly generated test problems shows that the heuristic algorithm gives relatively good solutions in a reasonable computation time.     

Economic lot-sizing and dynamic quantity competition

We study a problem of dynamic quantity competition in continuous time with two competing retailers facing different replenishment cost structures. Retailer 1 faces fixed ordering costs and variable procurement costs and all inventory kept in stock is subject to holding costs. Retailer 2 only faces variable procurement costs. Both retailers are allowed to change their sales quantities dynamically over time. Following the structure of the economic order quantity (EOQ) model, retailer 1 places replenishment orders in batches and retailer 2 follows a just-in-time (JIT) policy. The objective of both retailers is to maximize their individual average profit anticipating the competitor's replenishment and output decisions. The problem is solved by a two-stage hierarchical optimization approach using backwards induction. The second-stage model is a differential game in output quantities between the two retailers for a given cycle length. At the first stage, the replenishment policy is determined. We prove the existence of a unique optimal solution and derive an open-loop Nash equilibrium. We show that both retailers follow contrary output strategies over the order cycle. The EOQ retailer, driven by inventory holding costs, decreases his market share whereas the output of the JIT retailer increases. Moreover, depending on the cost structure, the EOQ retailer might partially be a monopolist. At the first stage, the EOQ retailer determines the cycle length, anticipating the optimal output trajectories at the second stage.     

Inventory control in a two-echelon dual-channel supply chain with setup of production and delivery

This paper considers a two-echelon dual-channel supply chain model with setup of production and delivery and develops a new inventory control policy for the supply chain. Previously, a two-echelon supply chain model without setup of production and delivery is considered and a one-for-one inventory control policy is applied to the supply chain. In the inventory control policy, production is stopped when the warehouse inventory reaches the upper limit and is started again immediately after the inventory drops below the limit. Moreover, delivery to the retailer is stopped when the store inventory reaches the upper limit and is started again immediately after the inventory drops below the limit. The total cost that consists of inventory holding costs and lost sales cost is considered, and setup costs are not considered in the total cost. Once setup costs are introduced, the one-for-one inventory control policy is no longer appropriate. Then, this paper develops a new control policy for the two-echelon dual-channel supply chain with setup of production and delivery. As performance measure, the total cost that consists of inventory holding costs, lost sales cost, and production and delivery setup costs is considered, and the total cost calculated on the basis of Markov analysis demonstrates the effectiveness of the proposed control policy.     

Supply contract with options

The purpose of this paper is to analyze the impact of an option contract for two companies of a supply chain: retailer and supplier. With an option contract the retailer orders a quantity of units and has the right to modify his order if necessary. A model to calculate the performance of an option contract in terms of contract value for the two companies engaged is presented. The two considered cases are multiple suppliers and one retailer, and one supplier and one retailer. The performance improvement obtained using this kind of contract is compared by simulation.     

Game theoretical perspectives on dual-channel supply chain competition with price discounts and pricing schemes

This paper evaluates the impact of price discount contracts and pricing schemes on the dual-channel supply chain competition. Channel conflict occurs when the supplier enters the online direct channel. Traditional contracts normally require tedious administrational participation, full information of the cost structures, and other factors. The introduction of simple price discount contracts aims at providing easy implementation and effective coordination results. From supplier Stackelberg, retailer Stackelberg, and Nash game theoretic perspectives, we show that the scenarios with price discount contracts can outperform the non-contract scenarios. In addition, we show consistent pricing scheme can reduce the channel conflict by inducing more profit to the retailer. The leader in the games might, but is not guaranteed to, have advantages.     

VMCI 下基于批发价决策权转移的供应链效率改进研究

本文在VMCI 模式下，考虑销售努力水平对市场需求的影响，研究批发价决策权由供应商转移至零售商的两级供应链效率改进问题。假定零售商决策批发价和销售努力水平，供应商决策寄售量，建立了零售商主导的Stackelberg 博弈模型，证明了集中决策下的最优解和分散决策下的均衡解均存在且唯一，集中决策下的寄售因子大于分散决策下的对应值。随后，引入收入共享与销售努力成本共担契约，论证了系统中寄售因子保持不变、批发价降低，且当契约参数满足一定条件时，可实现帕累托改进，实现供应链的效率改进。最后，分析了契约参数对于系统决策变量及利润的影响。     

Structuring and contracting in competing supply chains

This paper considers two competing supply chains, each with multiple upstream suppliers producing complementary products and selling to a single buyer (e.g., assembler or retailer), who then sells the finished assembled product to a market that involves both demand uncertainty and competition. Our main research questions focus on what supply chain structure (integration vs. decentralization) and which contracting strategy a business should choose. We find that supply chains that decentralize perform better under strong market competition (i.e., high degree of product substitution between supply chains). However, when a large number of suppliers exist, supply chains that integrate perform better. When decentralized structures are used for both supply chains, a consignment with revenue sharing contract generally outperforms a wholesale price contract from the downstream retailer's point of view. Interestingly, for a supplier, a wholesale price contract, which pushes all demand risks to the downstream retailer, might not be preferred. For the entire supply chain, one contract strategy can outperform another depending on the degree of competition, the cost share of the buyer, and the number of suppliers.     

An integrated production-distribution model for a deteriorating inventory item

We develop an integrated production-distribution model for a deteriorating item in a two-echelon supply chain. The supplier’s production batch size is restricted to an integer multiple of the discrete delivery lot quantity to the buyer. Exact cost functions for the supplier, the buyer and the entire supply chain are developed. These lead to the determination of individual optimal policies, as well as the optimal policy for the overall, integrated supply chain. We outline a procedure for determining the optimal supply chain decisions with the objective of minimizing the total system cost. Our approach is illustrated through a numerical example.     

Inventory management in supply chains: A bargaining problem

This paper is focused on supply chain management from the perspective of inventory management. The coordination of order and production policies between buyers and suppliers in supply chains is of particular interest. When a buyer of an item decides independently, he will place orders based on his economic order quantity (EOQ). However, the buyer's EOQ may not lead to a favorable policy for the supplier. A cooperative order and production policy can reduce total cost significantly. Should the buyer have the dominant position to impose his EOQ on the supplier, then consequently no incentive exists for him to deviate from his EOQ in order to choose a cooperative policy. To induce the buyer to order in quantities more favorable to the supplier, the supplier could offer a cooperative policy associated by a side payment to the buyer. The research presented in this paper provides several bargaining models depending on alternative production policies of the supplier. With these bargaining models the offered cooperative policy and the offered side payment can be derived.