不完美检验和顾客抱怨的供应链质量控制模型

由于最终产品的质量水平由供应商生产质量水平和分销商检验水平共同决定,将来料检验不完美和顾客抱怨纳入供应链质量控制模型。结果得到了双方博弈的均衡解,阐明了解的内涵和解的特征以及参数间的关系,并给出了均衡解为混合策略时解与分销商检验水平和顾客抱怨之间的互动机制。在理论上给出了分销商来料检验不完美情形下的分析模式和解的结构,并在应用上指明了来料检验水平和顾客抱怨对供应链质量控制的调节方法。     

Horizontal cooperation and information sharing between suppliers in the manufacturer–supplier triad

In this paper, we analyse a collusion and information-sharing problem between two suppliers in a manufacturer–supplier triad. The manufacturer treats one supplier as a strategic supplier and the other as a backup. While the strategic supplier offers modules of good quality but longer lead times, the backup supplier offers modules with inferior quality but shorter lead times. If there are urgent orders, the manufacturer must turn to the backup supplier. However, it is difficult for the manufacturer to estimate whether the urgent supplier has put extra effort into their production. We formulate this problem by assuming that the urgent supplier has either low or high production costs. To take advantage of the competition between two suppliers, the manufacturer can design a contract menu that defines total payment and lead times, under which both suppliers may be worse off. Meanwhile, it is possible for the suppliers to tacitly form a coalition, and to even share the private cost information. We study this problem by formulating it as a three-stage game. Furthermore, we investigate the variation of profits for each part of the supply chain. We find that the manufacturer is worse off when suppliers cooperate or share private information. Both suppliers, however, can benefit from cooperation and information sharing.     

The impact of contract parameters on the supply chain performance under different power constellations

Reporting forecast data is a common method used to improve the functioning of supply chains (SCs) and to reduce supply shortages. Customers tend to report the maximum possible demand as a forecast if restrictions are missing. Such a forecast is useless for suppliers. Hence, special contracts are needed to enhance the value of forecast data and therefore the cooperation between SC partners. In this paper, such a contract is presented. It encourages the customer to report a more realistic forecast. Deviations from the reported forecast are punished in different ways: If the customer reported too much and wants to release less than what was reported, he has to pay a penalty. On the other hand, the customer has the flexibility to purchase more than reported to meet the demand on his outlet but at the cost of an additional fee. This paper analyses how different contract parameters affect the performance of the SC, in particular when the bargaining power of customer and supplier is not equally distributed. Results show that the supplier and therefore the SC is better off if the supplier leaves the contractual cost parameters untouched but hides the true value of flexibility, especially when the customer is less powerful than the supplier.     

Moral hazard problem and collaborative coordination in supply chain with capacity reservation contract

This paper has considered collaborative coordination in supply chains with capacity reservation contracts using the game theory. In some traditional papers, the capacity reservation contracts have contained a capacity quantity, a reservation quantity and a reservation fee as a decision variable. Each decision variable is determined separately based on individual profit functions of a supplier and a manufacturer under the noncooperative game theory. Those papers have assumed that the supplier is always forced to build sufficient capacity to cover the reservation amount of the manufacturer. However, the supplier might not always comply with the reservation amount of the manufacturer since the capacity quantity is a private decision in the supplier and not released to external companies in practice. For instance, the supplier may choose to under-build knowingly to ensure high utilisation of his capacity. This is a kind of moral hazard problems. This paper has investigated such a strategy that the supplier and manufacturer voluntarily comply with the contract for the purpose of solving the moral hazard problem in the capacity reservation contract. Consequently, we have proposed a method of determining the decision variables collaboratively in the contract such that a consensus of the supplier and manufacturer is built.     

考虑零售商延期付款的供应链协调机制研究

在由一个供应商和一个零售商组成的两级供应链中,供应商允许零售商进行延期付款,研究了零售商所采取的单期订购决策及供应链协调问题.研究表明,允许零售商延期付款的斯塔克博格模型存在角点解均衡,供应商会占有所有供应链利润.分析得出了允许零售商延期付款的订购合同优于批发价格合同的条件以及供应链达到整体协调的条件.最后还研究了供应商提供零利率延期付款的合同,得出了供应商提供零利率延期付款的合同所实现的供应链利润优于允许零售商延期付款的斯塔克博格模型合同的条件.研究表明通过延期付款,供应商和零售商可以设计一个线性转移支付实现供应链效率的提升以及供应链协调.     

Supply chain coordination by risk sharing contracts under random production yield and deterministic demand

From numerous contributions to literature we know that properly designed contracts can facilitate coordinated decision making of multiple actors in a supply chain (SC) so that efficiency losses for the whole SC can be avoided. In a newsvendor-type SC with stochastic demand it is well-known that the double marginalization effect hampers the simple wholesale price contract to achieve coordination. More complex contracts however can bring about coordination, especially those which enable appropriate sharing of risks between the actors. While the effectiveness of risk sharing contracts is well understood for SC situations with random demand and reliable supply, less is known about respective problems if demand is deterministic but supply is unreliable due to random production yield. This paper shows how in a buyer-supplier SC the distribution of risks affects the coordination of buyer’s ordering and supplier’s production decision in a basic random yield, deterministic demand setting. Both parties are exposed to risks of over-production or under-delivery, respectively, if a simple wholesale price contract is applied. The resulting risk distribution always impedes SC coordination. However, more sophisticated contract types which penalize or reward the supplier can change risk distribution so that SC coordination is possible under random yield. Additionally, it is proven that the wholesale price contract will guarantee SC coordination if the supplier has a second (emergency) procurement source that is more costly, but reliable. Moreover, it is shown that under wholesale price contracts it can be beneficial to utilize this emergency source even if it is unprofitable from a SC perspective. However, if such an emergency option is available to the buyer as opposed to the supplier, a wholesale price contract will not be able to coordinate the SC.     

Efficient methods for comparing two process yields – strategies on supplier selection

Selecting an appropriate supplier can substantially reduce purchasing costs, decrease production lead time, increase customer satisfaction, and strengthen corporate competitiveness. Thus, an effective approach to alleviate the problem of supplier selection is essential. Numerous studies have indicated that quality is the most critical and fundamental factor for supplier selection and evaluation, among various criteria. This study provides several methods for selecting the superior supplier based on the commonly used quality criterion, process yield. Four tests for comparing two yield-measure indices, based on the normal approximation and generalised confidence intervals method, are presented and compared. This paper provides recommendations for selecting efficient methods, based on the simulation results of test size and selection power. An example is also presented to illustrate the applicability of these methods.     

The economic lot and delivery scheduling problem: models for nested schedules

We investigate the problem of simultaneously determining schedules for the production of several assembly components at a captive supplier and delivery of those components to the customer. We consider situations in which production economies of scale in the form of setup costs and/or setup times make it desirable for the supplier to produce in batches that are larger than the desired order quantity of the customer. The objective is to minimize the average cost per unit time of transportation, inventory at both the customer and the supplier, and, where applicable, setup costs.

We develop a heuristic solution procedure and a lower bounding approach for this problem. We also report experimental results that indicate that the heuristic provides solutions close to the lower bound in most instances. Our results provide a means to answer the often-asked question of whether just-in-time suppliers are (or should be) asked to hold inventory for their customers, and the question of how much setup costs and setup times need to be reduced so that the suppliers no longer need to hold that inventory.     

An integrated emergency ordering and production planning optimization model with demand and yield uncertainty

This paper proposes an integrated emergency ordering and production planning scheme for a multi-item, multi-product problem in which each product is composed of several ingredients. Each item can be supplied from both cheap unreliable suppliers prone to yield uncertainty and expensive reliable suppliers. A two-stage decision-making process is proposed in which orders are placed to the unreliable suppliers during the first stage and an emergency order can be placed in the second stage. In addition, a flexible backup ordering contract between the buyer and emergency supplier is proposed. A similar two-stage decision-making process is considered for production planning, where in the first stage, the main production plan is determined and in the second stage, the decision about a limited increase in the production plan is made as an emergency decision. An integrated ordering and production planning decision process is proposed for the problem. The value of emergency decisions, including the value of emergency ordering and the value of emergency production planning evaluates the effectiveness of the emergency decisions. Due to the staggering size of the problem, sample average approximation method is used to solve the problem.     

公平偏好下考虑双边保鲜努力的生鲜农产品供应链协调研究

针对供应商主导的生鲜农产品供应链,建立Stackelberg博弈模型;在考虑供应商、零售商双边保鲜努力水平影响生鲜农产品新鲜度和市场需求的情况下,分析零售商公平偏好对生鲜农产品供应链双边保鲜努力水平和供应链协调性的影响;采用委托代理模型对“批发价格 + 转移支付”的组合契约协调机制进行研究,旨在增加供应链整体利益及其稳定性,更好地协调成员之间的利益。研究表明,无论是否考虑零售商公平偏好,批发价格契约均无法实现生鲜农产品供应链协调,且零售商公平偏好会进一步降低双边保鲜努力水平、使供应链偏离最优。最后基于“批发价格 + 转移支付”的组合契约不仅能使双边保鲜努力水平达到集中决策下最优,实现生鲜农产品供应链协调,还能实现供应链成员利润的帕累托改进。     

Coordination of pricing,inventory, and production reliability decisions in deteriorating product supply chains

In this article, we study a two-level supply chain model for deteriorating items, in which the supplier’s production system is unreliable and the retailer’s demand is price-sensitive. The supplier’s production line may randomly shift from the in-control state to the out-of-control state. When the production line is in the out-of-control state, a proportion of the produced products will have bad quality. To mitigate the out-of-control risks, the supplier can improve the production line reliability by investing in high-quality machines, highly skilled workers, or advanced maintenance technologies. We start with the study of pricing and inventory problems concerning endogenous reliability in the integrated and decentralised scenario. To better illustrate the proposed models, two applicable algorithms are designed to determine the optimal production reliability, ordering quantity, and prices. Then, a cooperative reliability investment and revenue-sharing contract is proposed to coordinate the supply chain. Numerical examples and sensitivity analysis of the equilibrium strategies and coordinating results on key system parameters (e.g. deterioration rate, production rate, etc.) are given to verify the effectiveness of the contract, and meanwhile get some managerial insights.     

公平偏好下基于Stackelberg博弈的回购契约研究

引入公平偏好,构建了供应商与零售商进行Stackelberg博弈的回购契约模型,采用逆向归纳法分析了批发价的制定、回购契约的协调性以及供应链成员的公平偏好行为对批发价的影响。研究表明：无论是否考虑公平偏好,回购契约都不能实现供应链协调且公平偏好行为不会影响零售商的最优订购量。此外,供应商提供的批发价随着零售商公平偏好系数的增加而降低,但随供应商公平偏好的增加而升高。     

Supply chain models with corporate social responsibility

Currently, corporate social responsibility (CSR) has become a critical issue because more than 88% of consumers think companies should try to achieve their business goals while improving society and the environment. This paper focuses on a CSR supply chain where an Original Equipment Manufacturer’s (OEM’s) sales can be significantly reduced because of its oversea supplier’s social misconduct. Specifically, as in a conventional wholesale price contract the supplier determines its wholesale price and the OEM decides its order quantity, but in a CSR supply chain, the supplier can autonomously change its CSR cost once a minimum requirement is satisfied. A higher CSR cost means that the supplier invests more in its corporate social responsibility and the OEM’s sales will be less likely to be influenced by negative CSR events. The equilibrium solutions show an important dilemma – although the supplier’s profit increases in the basic CSR requirement, the supplier will always use the minimum CSR cost under the conventional wholesale price contract, which eventually leads to a low supply chain profit. Thus, we introduce two different contracts to handle this problem: the flexible quantity contract and the wholesale price incentive contract, which are, respectively, a ‘tough’ way and a ‘beneficent’ way for the OEM to solve the problem. Although the two ways cannot (always) coordinate the supply chain, we show that they both will significantly improve the supply chain performance. Our results also show that in some conditions, one strategy will dominate, whereas in different conditions the other strategy dominates.     

A study on capacity allocation scheme with seasonal demand

This paper studies a game-theoretical capacity allocation problem in a two-echelon supply chain comprised of one supplier and N retailers. With demand fluctuating seasonally and significantly, supply is sufficient in low-demand periods but is insufficient in high-demand periods, especially when the supplier’s capacity decreases in high-demand periods. Retailers compete for the supplier’s capacity in high-demand periods, but do not want to absorb the supplier’s redundant capacity in low-demand periods. A turn-and-earn allocation scheme is proposed to encourage retailers to increase their order quantity in low-demand periods. Under the turn-and-earn allocation scheme, in high-demand periods, the supplier is willing to offer a guaranteed portion of supply capacity for the primary retailer. The remaining capacity in high-demand periods is allocated based on orders retailers placed in low-demand periods. In response, the retailers will decide how much they should order in low-demand periods. Then, a competitive game based on Nash equilibrium among the supplier and her retailers is analysed. In order to solve the problem of unreasonable distribution of interest caused by competition, a contract is designed to make it possible for subsidy to be transferred from the supplier to the retailers. Usually, the supplier and her primary retailer can both be better off under turn-and-earn allocation compared with fixed allocation, and the system efficiency in Nash solution is close to it in optimal solution. A numerical study is also conducted to discuss the parties’ sensitivity to different demand level and guaranteed allocation portion of capacity.     

需求和提前期不确定下的两级供应链系统研究

由一个部件提供商和一个装配商组成的两级组装供应链系统,部件提供商提供两种不同的部件给装配商进行装配;分析在单销售周期内,系统上同时存在部件的生产提前期和装配提前期的不确定,以及需求的不确定时,系统的特性.采用博弈论方法,装配商确定装配计划提前期,以及向部件提供商提交的订购量;而部件提供商确定部件生产计划提前期,以及部件批发价格.得出,首先,不确定提前期导致供应链系统订购量减小;其次,在分散控制的组装供应链系统中,系统的总生产、装配计划提前期,要大于集中控制系统中的,并且装配计划提前期与部件生产计划提前期无关;再者,过大的提前期不确定性对组装供应链系统的影响要比需求不确定对组装供应链的影响大.     

紧急订单成本信息不对称下的激励契约设计

在正常订单和紧急订单供应商共存情况下.分析制造商的最优订货策略.正常订单供应商采购提前期较长.需在销售期前进行订货.紧急订单供应商交货期较灵活.但交货期长短与成本相关且该成本信息为其私有信息.考虑在此条件下制造商的订货策略(与正常订单供应商)和激励合同设定问题(与紧急订单供应商).最后,比较了紧急订单供应商的存在与否对制造商的订货以及利润的影响.     

Positive implications of market valuation under asymmetric quality information

We investigate a buyer’s contract design problem in which the buyer’s supplier has private quality cost information and is concerned with market valuation. We characterise the parameters of the contract menu (including quantity, quality level and transfer payment) and determine the market price. Our results show that the supplier’s market value concern (MVC) has positive implications and mitigates the distortion of quality level. Although both the buyer and the entire chain system benefit from this MVC, it may give advantage or disadvantage to the supplier of the low-cost type, depending on this supplier’s efficiency and the extent of the MVC. Numerical study reveals that the buyer is insensitive to the pricing decision, which suggests that contracts subject to the optimal market price without MVC serve as a good heuristic.     

单供应商面对具有多个销售点的零售商时的VMI模型研究

在供应商管理用户库存（VMI）环境中,当面临的具体条件不同时,供应商和零售商的利润分配是不同的,论述了当一个供应商面对具有多个销售点的零售商时的VMI模型,此时供应商负责库存决策,他可以在各个销售点之间转运（Transshipment）库存.建立了供应商和零售商的一个Stackelberg博弈,零售商作为领导者是通过决定销售价格来体现的.结果显示最终供应商和零售商可以达到一个子博弈精练纳什均衡,零售商在该模式下获得了很大的利润份额.给出了一个算例计算了均衡时的库存量和销售价格.     

Integrating order acceptance decisions with flexible due dates in a production planning model with load-dependent lead times

We consider a tactical planning problem, which integrates production planning decisions together with order acceptance decisions, while taking into account the dependency between workload and lead times. The proposed model determines which orders to accept and in which period they should be produced, so that they can be delivered to the customer within the acceptable flexible due dates. When the number of accepted orders increases, the workload and production lead time also increase, and this may result in the possibility of missing customer due dates. This problem is formulated as a mixed integer linear programme for which two relax-and-fix heuristic solution methods are proposed. The first one decomposes the problem based on time periods, while the second decomposes it based on orders. The performances of these heuristics are compared with that of a state-of-the-art commercial solver. Our results show that the time-based relax-and-fix heuristic outperforms the order-based relax-and-fix heuristic, and the solver solution as it yields better integrality gaps for much less CPU effort.     

Costing-based coordination between mt-iPSS customer and providers for job shop production using game theory

The industrial product-service system for Computer Numerical Control machine tool (mt-iPSS) has drawn much interest. Under the new paradigm of functional result-oriented mt-iPSS, mt-iPSS customer (i.e. owner of the workshop) pays for time or results of mt-iPSS providers. The present problem for mt-iPSS customer is how to timely identify the optimal machine tools, sequence and cutting parameters of operation to finish the jobs while mt-iPSS providers try to maximise their benefit in a non-cooperative game structure. In this paper, a Stackelberg game model is put forward to solve the coordination problem based on the costing of different job shop scheduling solutions under the result-oriented mt-iPSS paradigm. Then, to solve the established bi-level programming model of the Stackelberg game, a solution procedure based on hierarchical particle swarm optimisation is proposed. Finally, a case from a printing machinery enterprise is analysed to validate the proposed model. This research is expected to improve the quality and effectiveness of coordination for scheduling and process planning decision between mt-iPSS customer and multi-providers.