Supply chain risk, simulation, and vendor selection

This paper considers three types of risk evaluation models within supply chains: chance constrained programming (CCP), data envelopment analysis (DEA), and multi-objective programming (MOP) models. Various risks are modeled in the form of probability and simulation of specific probability distribution in risk-embedded attributes is conducted in these three types of risk evaluation models. We model a supply chain consisting of three levels and use simulated data with representative distributions. Results from three models as well as simulation models are compared and analysis is conducted. The results show that the proposed approach allows decision makers to perform trade-off analysis among expected costs, quality acceptance levels, and on-time delivery distributions. It also provides alternative tools to evaluate and improve supplier selection decisions in an uncertain supply chain environment.     

Supplier selection-order allocation: A two-stage multiple criteria dynamic programming approach

This paper proposes a two-stage multiple criteria dynamic programming approach for two of the most critical tasks in supply chain management, namely, supplier selection and order allocation. In the first stage, to address multiple decision criteria in supplier ranking, the analytic hierarchy process (AHP) is employed. In the second stage, supplier ranks are fed into an order allocation model that aims at maximizing a utility function for the firm as well as minimizing the total supply chain costs, subject to constraints on demand, capacity, and inventory levels. A dynamic programming approach is crafted to solve the proposed bi-objective model.     

A decision method for supplier selection in multi-service outsourcing

Although supplier selection in multi-service outsourcing is a very important decision problem, research concerning this issue is still relatively scarce. This paper proposes a decision method for selecting a pool of suppliers for the provision of different service process/product elements. It pioneers the use of collaborative utility between partner firms for supplier selection. A multi-objective model is built to select desired suppliers. This model is proved to be NP-hard, so we develop a multi-objective algorithm based on Tabu search for solving it. We then use an example to show the applicability of the proposed model and algorithm. Extensive computational experiments are also conducted to further test the performance of the proposed algorithm.     

An improved model for supplier selection under capacity constraint and multiple criteria

Ghodsypour and O'Brien [2001. The total cost of logistics in supplier selection, under conditions of multiple sourcing, multiple criteria and capacity constraint. International Journal of Production Economics 73(1), 15–27] study multiple sourcing problem with multiple criteria and capacitated suppliers. Considering the buyer's quality requirements as a constraint, they develop a mixed integer non-linear programming model to find the least-cost cyclic ordering policy for the buyer. They propose to solve the model by enumerating over all possible supplier combinations. Although the problem is interesting and their analysis is correct, we point out two issues with their assumptions, namely, capacitated suppliers and cyclic ordering policy. We discuss two different capacitated supplier settings: (i) long-run average annual capacity, and (ii) exact annual capacity. First, under long-run average annual capacity assumption we propose a model which provides the same or a better solution and is much easier to solve than their model. Then, we discuss how to modify our and their models to handle exact annual capacity assumption.     

Development and implementation of customer solutions: A study of process dynamics and market shaping

A broad, dynamic network perspective on solution processes remains scarce. This article presents the process of developing and implementing customer solutions and its effects on the wider business environment by investigating customers and suppliers in the global mining industry (Australia, Chile, and Sweden), analyzing the deployment of a new customer solution, and assessing the changes to the competitive environment and focal firms' relationships with other customers and suppliers. It shows that the forces that drive customer and supplier interests and motivation to co-develop customer solutions may change over time, thus redefining the aim and scope of solutions and creating failure risks. Customers present problems; suppliers respond, on the basis of not only the feasibility of the customer-specific solution but also of their evaluation of future solutions in a broader market; then suppliers aim to standardize successful solutions across markets. Customers want close supplier relationships and unique solutions but also like standardized and repeatable solutions, so they can share development costs with competitors and expose the supplier to competition to avoid lock-in effects. From a network perspective, a novel solution can have a market-shaping effect and evoke reactions from other actors who want to enhance their market position. However, these changes are not necessarily deliberate, and the dynamics that market introductions of solutions trigger may be difficult to predict.     

基于改进TOPSIS法的供应商选择模型研究

为有效地帮助企业快速找到合适的供应商合作伙伴,采用直觉模糊集、评分函数等方法对TOPSIS评估法进行优化,并以此为基础建立了一种供应商选择模型。首先,采集和评估供应商的产品质量、产品价格、产品交货的可靠性、供应位置、财务情况、库存水平、劳资关系、发展能力和技术能力等相关信息,由专家给出主观评估信息,汇总为综合属性值;然后,通过直觉模糊熵确定各评估指标的权重;最后,综合考虑供应商选择决策过程中的多个目标和标准,应用改进TOPSIS法的对供应商进行分类选择。结果显示,基于改进TOPSIS法的供应商选择模型能够较准确地反映出各供应商的真实水平和对企业的潜在价值,可以有效地解决不确定条件下对供应商的选择问题,提高了供应商选择结果的可靠性。改进后的模型简便易行,具有良好的稳定性,对于合理制定企业供应商选择标准以及进一步优化决策模型具有一定的借鉴意义。     

Robust supply base management: Determining the optimal number of suppliers utilized by contractors

The importance of robust supply base management under demand uncertainty requires an understanding of the benefits associated with a contractor having an optimal number of suppliers. The key benefit is a reduction in a contractor's total cost of supply base management. However, few supplier-optimizing models incorporate the perspectives of both demand uncertainty and supply base management costs. The objective of this paper is twofold: (1) to investigate the dynamics between demand uncertainty and coordination; and (2) to develop a model that determines the optimal number of suppliers that a contractor should maintain in its supply base to become more flexible and maximize its profits.     

COST,QUALITY, AND ENVIRONMENTAL TRADEOFFS FOR PRINTED CIRCUIT BOARD ASSEMBLY

After exhausting all “pollution prevention pays” opportunities, further efforts towards environmental protection often engender some type of cost to the manufacturer. Then, designers must weigh tradeoffs between environmental impacts and equally pressing needs to reduce costs, improve product quality, and reduce cycle time: all while meeting customer demands, which are the driving force behind the design process. Although there is a growing market for “green” products as customers' desire to be environmentally responsible increases, it is extremely difficult to accurately assess the customer's actual willingness to pay for environmental protection. This paper first briefly reviews methods for assessing customer preferences. Then, it presents a decision model for use by design engineers to assist in making these tradeoffs between cost, quality, and environmental impact in which customer preferences can be reflected in weighting factors assigned by the design engineer. Qualitative HOQ information is used as a starting point to derive a mathematical programming formulation for multiobjective optimization. Finally, an illustrative example for printed circuit board assembly is provided.     

基于贝叶斯理论的供电公司购电风险决策研究

将“供电公司如何从合约市场和实时市场中购买电力,以使自己的收益最大,风险最小”理解为一个风险型决策问题,应用贝叶斯分析理论,求得已知先验概率情况下供电公司的最小期望损失,改进了供电公司设定的先验概率,减少了期望损失,给出了供电公司应选择的决策方案,可供供电公司根据自身实际情况和电力市场相关信息做出正确的估计,保证供电公司做出正确的决策,从而实现收益最大化的目标。     

Performance feedback and supplier selection: A perspective from the behavioral theory of the firm

Drawing upon the behavioral theory of the firm, this study explores the behavioral antecedent of buying firms' decisions in supplier selection through relational referrals, beyond the predominant argument from relational network theory. Centering on the risk and uncertainty of searching for new suppliers, this study attempts to integrate the behavioral theory and relational network theory in explaining buying firms' supplier selection. Data from 112 Chinese manufacturing firms were used to test the hypotheses. The results suggest that performance feedback triggers buying firms' decision on the extent of reliance on relational referrals to select suppliers. Outperforming firms are more likely to use relational network to select suppliers while underperforming firms are less likely to use. This relationship will be strengthened when the intensity of market competition and specific investment in buyer-supplier relationship are high.     

Negative default dependence in supplier networks

The financial defaults of suppliers in a supplier network are significant risks and causes of uncertainty for buying firms. Hitherto, it has been largely neglected that default probabilities of suppliers in supplier networks are not independent of each other. We aim to overcome this shortcoming by studying negative supplier default dependencies: situations where a surviving supplier may benefit from the default of another supplier, resulting in a lower default probability. We use empirical data from the automotive supplier industry and copula functions, a method of representing joint distribution functions with particular marginals, to capture the default dependency between automotive suppliers and simulate various scenarios with negative default dependency. We also conduct a comparative static analysis illustrating the significant impact of negative default dependence. Our findings should spur managers to analyze their supplier networks with respect to default dependencies, and to take this phenomenon into consideration when making sourcing decisions.     

供应中断下双源采购的供应链契约设计

考虑由一个制造商和两个供应商构成的两级供应链契约设计问题,将可靠性服从随机分布的供应商作为主供应商,将完全中断供应商作为次供应商,建立以利润最大化为目标的签约和执行两阶段博弈的动态规划模型,得到制造商的最优契约设计。制造商根据产品零售价格的变化灵活做出只与一个供应商签约、与两个供应商同时签约或都不签约的决定,供应商根据契约设计内容决定自己的最优生产规模。研究表明：供应商最优生产规模与产品的单位生产成本呈负相关,与单位变动支付和单位惩罚成本呈正相关;次供应商的订货量与其本身的可靠性呈正相关,与主供应商的可靠性呈负相关;供应商的固定支付与其相应的可靠性呈负相关。     

Lot sizes in a capacity constrained facility—a simulation study of stationary stochastic demand

This paper considers the scheduling of several different items on a single machine, in literature known as the economic lot scheduling problem, ELSP. One of the characteristics of this problem is that the demand rate is deterministic and constant. However, in a practical situation demand usually varies. In this paper we examine if a deterministic model can be used if demand is stationary stochastic. A dynamic programming approach from Bomberger (Manage. Sci. 12(11) (1966) 778) and a heuristic method from Segerstedt (Int. J. Production Econom. 59(1–3) (1999) 469) are used to calculate lot sizes for four items. The production of these items is simulated with different variations in demand rates. Our conclusion is that a deterministic model of this kind can be used in a practical situation where the demand rate is stationary stochastic, but the models must be complemented by a decision rule; which item to produce and when to produce it. In our tests the heuristic method and the dynamic programming approach perform rather similarly with respect to costs and inventory levels, but the dynamic programming approach results in more backorders when there is small variation in demand rates. This study indicates that the model used for determination of lot sizes is of less importance than the decision rule used for identification of the item to produce and when to produce it.     

项目组合选择研究：基于模糊理论的模型建构及验证

项目组合的选定与企业经营息息相关,然而传统的选择方法存在许多限制。本文应用模糊理论建构一个项目组合的决策模型,模型中纳入了成本、利润及风险等3个决策因子,探讨在资源有限的情况下项目成本及获利的交互影响关系,并利用模糊归属函数建构一个数学规划模型。为了验证模型的有效性,用此模型与传统模型进行求解比较,证实了所提出模型的实用性。     

基于供应链的煤炭企业供应商管理研究

煤炭企业的生产特点和物资需求特性,决定了煤炭企业应该进一步改革物资采购模式,完善供应商管理工作。为有效跟踪供应商绩效表现,降低供应链风险,基于供应链管理理论提出目前中国煤炭企业应实施供应商全生命周期管理,并将供应商分类、供应商评价体系和关系管理纳入企业信息化系统建设中,有助于企业实现全方位的供应商关系管理。     

基于最小期望损失的供应链供货违约等级识别模型

本文全面研究了引起供应链供货违约的各种原因,从供应商自身因素、客户需求、双方信息集成以及供货渠道中的意外义素4个维度构建了一套供应链供货违约二级指标体系,用先进的模式识别技术定量解决了供货违约严重程度识别的问题。先用主成分分析法降低了指标维度,接着用多维正态分布分类模型衡量了每种违约等级发生的后验概率,最后在合理构造损失矩阵的基础计算出每种决策产生的期望风险,并依此做出违约等级的识别决策。通过实例计算表明该方法是可行的,识别结果具有一定的客观性。     

Buyer Market Power and Innovative Activities

This empirical paper deals with the effects of supplier and buyer market concentration on the innovative behavior of suppliers within the German automobile industry. The data set contains firms from all size classes and covers measures of innovation input as well as innovation output. It can be shown that (a) firms' innovation and R & D-employment intensity will decline (increase) in buyer concentrations if supplier markets are low (high) concentrated; (b) buyers' pressure on input prices reduces suppliers' innovation expenditures and their incentive to develop new products; (c) a small number of competitors in suppliers markets and a large stock of customers stimulates innovative behavior; (d) small and medium sized suppliers invest more in their innovative activities but have less probability of realizing innovations than larger firms; and (e) higher technological capabilities lead to higher innovation input and output.     

回收数量受价格和随机因素影响的定价模型

假设在再制造闭环供应链中,集中决策者、第三方和制造商分别从最终客户那里回收废旧品,其回收数量受回收价格和随机因素影响,制造商对获得的旧部件进行再制造,如果旧部件不能满足生产需求,制造商将从新部件供应商那里以高价格采购新部件来补充短缺。本文按照废旧品回收的供应链成员不同,建立了3个定价决策模型,证明了每个模型最优解的存在性和唯一性,然后在特殊情形下进一步求得各模型最优解的解析式,最后用具体算例对模型进行了验证。     

Reliability evaluation and adjustment of supply chain network design with demand fluctuations

This study focuses on supply chain network design problems by considering economies of scale and demand fluctuations. A reliability evaluation method is developed to evaluate the performance of plants under demand fluctuations. In addition, two mathematical programming models are developed to determine the optimal adjustment decisions regarding production reallocation among plants under different fluctuating demands. The judgments to adjust or to do-nothing are investigated by comparing the results if the adjustment is made or not made. Results show that making adjustments benefits the manufacturers by reducing total production cost and avoiding revenue loss, which outweighs the extra costs, especially for high value-added products. Results also suggest that the manufacturer should ignore a short period abnormal state, since the benefits to respond to it might not compensate the high allocation costs. The results of this study provide a reference for the manufacturer in their decision making process of network planning with demand fluctuations, when they have to cope with benefits and costs during abnormal states.     

Pivotal Buyers and Bargaining Position

Securing sales to a large buyer can be pivotal to a supplier's decision to produce. While conventional wisdom suggests that being pivotal improves a buyer's bargaining position, the opposite is shown in a multilateral bargaining model. If other buyers' payments fall short of costs, a pivotal buyer must cover the shortfall or forfeit consumption. This affords leverage that the supplier lacks when bargaining with non-pivotal buyers. The analysis illuminates contracting in markets with high fixed costs, such as cable television programming, motion pictures, and large-scale project finance, and has implications for the FCC's horizontal ownership limits on cable system operators.