Prioritizing edge over node: process control in supply chain networks and push-pull strategies

We outline recent work identifying an equilibrium solution in a supply chain network. The solution overcomes some difficulties associated with the bullwhip effect through limited cooperation and coordination along edges (links) in the supply chain network. The links constitute the stochastic modelling entities rather than the nodes of the network. We outline a range of feedback mechanisms that monitor and restore equilibrium in a supply chain. One of these is prediction capability charts which monitor the process. These charts are used by the decision makers to profile the allocation of inventory in the supply chain and identify out of control conditions. They maintain quality within the network, as well as intelligently track the way the network evolves in conditions of changing variability. We illustrate with an example simulating a push strategy in the clothing industry.     

具过度自信零售商的双渠道供应链网络均衡研究

将零售商的过度自信行为纳入双渠道供应链网络均衡模型,研究了由供应商、分销商以及具过度自信行为的零售商构成双渠道供应链网络均衡问题。借助变分不等式以及互补理论,刻画了制造商、分销商以及过度自信零售商的最优行为,并构建了双渠道供应链网络均衡条件。解析分析了市场出现有利信息和不利信息两种情形下,零售商的过度自信行为对其订购决策的影响。最后,数值算例验证上述结论,并借助数值结果分析了零售商的过度自信行为对双渠道网络均衡的影响。     

不同渠道权力结构下的双渠道闭环供应链定价与协调决策

在双渠道环境下,针对不同渠道权力结构对闭环供应链最优决策的影响情况,构建了三种分散化(制造商主导的Stackelberg博弈、零售商主导的Stackelberg博弈以及由制造商和零售商构成的Nash均衡博弈)和一种集中化的闭环供应链决策模型,并得出了相关的均衡策略。在此基础上进一步有针对性的设计了两种契约相结合的契约机制协调供应链,并利用数值算例分析验证所得结论以及契约机制的有效性与可实践性,同时分析模型中的一些重要参数如渠道替代系数、传统渠道所占市场份额、废旧产品回收率、再制造成本节约等对双渠道供应链各项最优决策及渠道利润的影响。     

外包策略下的三级供应链系统协调问题研究

由于存在着激烈的商业竞争,供需匹配成为供应链追求高绩效的关键.本文在制造商采取产能外包的策略下,引入二次采购契约研究制造商和销售商之间的契约订货问题.研究表明:1)供应链上存在一个核心企业来主导供应链契约的制定;2)本文设计的二次采购契约机制对分散式供应链的协调是有效的;3)制造商通过产能外包解决由于销售商的二次采购造成的缺货,可以使其更好地满足销售商的产品需求,进而提高供应链整体收益.最后,通过算例对研究结果作进一步说明.     

Equilibrium analysis and corporate social responsibility for supply chain integration

This paper evaluates the profit of coordination between manufacturers on corporate social responsibility (CSR) under network equilibrium. A three-tier supply chain network with multiple manufacturers, distributors, and retailers is considered, and several mathematical models are established to investigate behavior and profits in a decentralized supply chain network, a centralized supply chain network, and a supply chain network with CSR. The system-optimal solution of a supply chain network problem is usually not achievable or stable since each member always tries to maximize its own profit. In order to make such a system-optimal solution in a stable state and ensure the maximization of total profits, a strategy of coordination between manufacturers on CSR is proposed. The amount of payment in CSR of each manufacturer is clearly defined. A hybrid diagonalization method with a super-network representation is proposed and tested with numerical examples. The results show that by taking CSR, the total profits of the whole supply chain network can increase with or without coordination.     

A supply chain model with direct and retail channels

We study a dual channel supply chain in which a manufacturer sells to a retailer as well as to consumers directly. Consumers choose the purchase channel based on price and service qualities. The manufacturer decides the price of the direct channel and the retailer decides both price and order quantity. We develop conditions under which the manufacturer and the retailer share the market in equilibrium. We show that the difference in marginal costs of the two channels plays an important role in determining the existence of dual channels in equilibrium. We also show that demand variability has a major influence on the equilibrium prices and on the manufacturer’s motivation for opening a direct channel. In the case that the manufacturer and the retailer coordinate and follow a centralized decision maker, we show that adding a direct channel will increase the overall profit. Our numerical results show that an increase in retailer’s service quality may increase the manufacturer’s profit in dual channel and a larger range of consumer service sensitivity may benefit both parties in the dual channel. Our results suggest that the manufacturer is likely to be better off in the dual channel than in the single channel when the retailer’s marginal cost is high and the wholesale price, consumer valuation and the demand variability are low.     

On Hölder continuity of solution maps to parametric vector primal and dual equilibrium problems

In this paper, we first propose some kinds of the strong convexity (concavity) for vector functions. Then we apply these assumptions to establish sufficient conditions for the Hölder continuity of solution maps of the vector primal and dual equilibrium problems in metric linear spaces. As applications, we derive the Hölder continuity of solution maps of vector optimization problems and vector variational inequalities. Our results improve and generalize some recent existing ones in the literature.     

Bullwhip effect in a supply chain model with multiple delivery delays

We develop a model of differential equations for a supply chain with delivery time delays between every adjacent firms. Based on the supply chain model, we provide a new perspective of the bullwhip effect and show that the bullwhip effect is intrinsic in supply chains in the sense that the equilibrium state of each firm in the supply chain is a cumulative forward product of the ratios of order fulfillment and placement between adjacent firms toward the end customer demand. We also show that it is the multiple time delays instead of the constant end consumer demand that determine the stability of the equilibrium states. However, the consumer demand has impacts on the stability of the equilibrium states of the supply chain when the end retailer’s inventory decisions are linearly related to the end consumer demand.     

基于模糊加值信息的供应链协调均衡研究

研究由一个供应商和两个零售商组成的供应链共享信息均衡问题。两个零售商具有不同的私有成本信息。当零售商不公开此成本信息时,其他的零售商和供应商只能推断出该信息的模糊分布。不同市场需求参数下,使零售商和供应商均达到最大利润的局势也有所不同。为了使供应链上的供应商和零售商达到双赢,分析了各同均衡策略存在的前提条件。     

双渠道闭环供应链的三种回收模式的建模分析

针对生产商负责网上直销、零售商负责网下零售、且具有回收再制造功能的双渠道闭环供应链,首先分析了生产商负责产品回收和零售商负责产品回收下生产商和零售商之间的博弈行为,建立了刻画两种回收模式的两层规划模型;进而假定生产商委托第三方企业负责回收,分析了生产商、零售商和第三方回收企业之间的博弈行为,建立了对应此一主两从博弈结构的带均衡约束的两层规划模型.对所得模型进行了模型求解,得到了三种回收模式下双渠道闭环分散式供应链的最优直销价、零售价和回收再制造率决策.通过数值算例对上述三种回收模式进行了比较分析,并对刻画网上直销吸引力的相关参数进行了灵敏度分析.研究发现,生产商负责回收时的回收再制造率最高;网上直销具有激发潜在需求(正效应)和吸引零售市场需求发生转移(负效应)的双重效应等.     

双渠道供应链协调及价值扰动

本文研究了消费者选择行为给出的需求模型下双渠道供应链的协调与价值扰动问题.利用Stackelberg博弈对系统建模及其应急管理方法考虑价值扰动问题,获得了扰动前的Stackelberg博弈系统的均衡解和中心决策系统的最优解对价值扰动具有一定的橹棒性的结果,推广了供应链中的应急管理研究结果.     

基于风险管理的动态供应链超网络均衡模型

基于风险管理的动态供应链超网络均衡模型的研究有助于供应链超网络节点厂商在动态环境下优化其风险管理,降低风险损失,提升供应链网络在风险管理下的竞争优势。本文以三层供应链超网络为研究对象,采用风险发生概率和损失函数表达供应链超网络中节点厂商中断风险的特征,构建了基于风险管理的动态供应链超网络均衡模型。模型中包括三种类型的节点,产品生产商、零售商和需求市场,生产商考虑风险损失的情况下,基于动态变化的风险、需求和成本追求个体期望效益最优化。接着,通过进化变分不等式来表达动态供应链超网络风险管理下的均衡解,并采用投影动态系统求解进化变分不等式,通过数值算例验证方法的可靠性和合理性,通过投影动态系统解释某一个厂商趋近均衡解的过程。通过单一厂商趋近均衡解的过程,阐述其他厂商相应的最优决策。     

广告分担、价格折扣与供应链的纵向合作广告

研究了生产商和零售商的纵向合作广告问题。分别在广告分担和价格折扣策略下，探讨了双方的均衡结果和利润。当生产商的边际利润较小时，生产商的最优决策是不采取任何一种策略。当生产商的边际利润达到一定范围时，广告分担策略是双方共同的最优选择。而无论在什么样的条件内，价格折扣策略都不会使双方同时满意。为了增加双方的收益，供应链成员应该在广告上集成决策。最后给出了系统集成的可行最优解的范围和Nash讨价还价解。     

Game-theoretic analyses of decentralized assembly supply chains: Non-cooperative equilibria vs. coordination with cost-sharing contracts

This paper considers a multiple-supplier, single manufacturer assembly supply chain where the suppliers produce components of a short life-cycle product which is assembled by the manufacturer. In this single-period problem the suppliers determine their production quantities and the manufacturer chooses the retail price. We assume that the manufacturer faces a random price-dependent demand in either additive or multiplicative form. For each case, we analyze both simultaneous-move and leader–follower games to respectively determine the Nash and Stackelberg equilibria, and find the globally-optimal solution that maximizes the system-wide expected profit. Then, we introduce appropriate buy-back and lost-sales cost-sharing contracts to coordinate this assembly supply chain, so that when all the suppliers and the manufacturer adopt their equilibrium solutions, the system-wide expected profit is maximized.     

Bargaining in competing supply chains with uncertainty

Substantial literature has been devoted to supply chain coordination. The majority of this literature ignores competition between supply chains. Moreover, a significant part of this literature focuses on coordination that induce the supply chain members to follow strategies that produce the equilibria chosen by a vertically integrated supply chain. This paper investigates the equilibrium behavior of two competing supply chains in the presence of demand uncertainty. We consider joint pricing and quantity decisions and competition under three possible supply chain strategies: Vertical Integration (VI), Manufacturer’s Stackelberg (MS), and Bargaining on the Wholesale price (BW(α), α is the bargaining parameter) over a single or infinitely many periods. We show that, in contrast to earlier literature, using VIVI (VI in both chains) is the unique Nash Equilibrium over one period decision, while using MSMS or BW(α)BW(α) may be Nash Equilibrium over infinitely many periods.     

Strategic interactions in service supply chain with horizontal competition

We analyze strategic interaction issues that arise in service supply chain, such as consulting, service outsourcing, and travel service. To capture strategic interactions in service supply chain, we study a case where there are two service vendors providing competing service products and selling them through a common Service Integrator. In particular, we derive and compare equilibrium solutions (e.g. service prices, wholesale prices, service volumes) for the service supply chain under three different scenarios. We then study the effect of key parameters in the model upon the equilibrium solution using sensitivity analysis, and discuss our results along with a numerical experiment. Finally, future research direction is pointed out.     

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.     

Semi-Lagrangean approach for price discovery in markets with non-convexities

From standard economic theory, the market clearing price for a commodity is set where the demand and supply curves intersect. Convexity is a property that economic models require for a competitive equilibrium, which is efficient and well-behaved and provides equilibrium prices. However, some markets present non-convexities due to their cost structure or due to some operational constraints that need to be addressed. This is the case for electricity markets where the electricity producers incur costs for shutting down a generating unit and then bringing it back on. Non-convex cost structures can be a challenge for the price discovery process, since the supply and demand curves may not intersect, or if they intersect, the price found may not be high enough to cover the total cost of production. We apply a Semi-Lagrangean approach to find a price that can be applied in the electricity pool markets where a central system operator decides who produces and how much they should produce. By applying the model to an example from the literature, we found prices that are high enough to cover the producer’s total costs, and follows the optimal solution for achieving mining cost in production. The prices are an alternative solution to the price discovery problem in non-convexities economies; in addition, they provide nonnegative profits to all the generators without the use of side-payments or up-lifts, and closes the integrality gap.     

具有单向转载的Newsboy型产品订货决策的博弈模型

研究了允许单向横向转载的Newsboy型产品的订货决策问题。以两个Newsboy型零售商为研究对象,在允许单向横向转载存在的前提下,构建了以二者期望利润最大化为目标的非合作博弈模型,讨论了模型存在纳什均衡解的条件并证明了解的存在性与唯一性,给出了均衡解的解析表达形式,进一步分析了转载价格对均衡的影响。最后的算例分析则从期望利润、均衡订货和转载价格三个方面验证了横向转载策略的优势。研究表明:(1)与传统报童模型相比,横向转载策略提高了零售商的期望利润;(2)转载价格显著影响横向转载策略下零售商的订货决策。     

Competitive facility location on decentralized supply chains

This paper addresses a novel competitive facility location problem about a firm that intends to enter an existing decentralized supply chain comprised of three tiers of players with competition: manufacturers, retailers and consumers. It first proposes a variational inequality for the supply chain network equilibrium model with production capacity constraints, and then employs the logarithmic-quadratic proximal prediction–correction method as a solution algorithm. Based on this model, this paper develops a generic mathematical program with equilibrium constraints for the competitive facility location problem, which can simultaneously determine facility locations of the entering firm and the production levels of these facilities so as to optimize an objective. Subsequently, a hybrid genetic algorithm that incorporates with the logarithmic-quadratic proximal prediction–correction method is developed for solving the proposed mathematical program with an equilibrium constraint. Finally, this paper carries out some numerical examples to evaluate proposed models and solution algorithms.