网上拍卖销售与逆向拍卖采购下的库存管理

以电子商务为背景研究网上拍卖销售与逆向拍卖采购下的库存管理。在该问题中,零售商一方面利用网上拍卖销售产品,另一方面利用逆向拍卖进行采购。对于单阶段情形,证明网上拍卖下零售商的期望收益函数是采购量的严格递增的凹函数,从而得到零售商的最优采购策略和供应商的最优投标策略。对于多阶段情形,利用马尔可夫决策过程理论建立该问题的最优控制模型,得到零售商的最优采购策略和供应商的贝叶斯-纳什均衡投标策略均与基本库存策略相类似。     

供应风险下双源采购批发单价拍卖最优设计

考虑多个具有供应风险和成本私有信息的潜在供应商,研究了供应商投标批发单价的最优双源采购拍卖机制设计.首先,针对一般的采购商收益函数,求出了最优的订货量分配规则和供应商投标均衡,并分别与单源采购及对称信息对比,发现双源采购拍卖增加了采购商和供应商的期望利润,不对称信息对供应商有利但对采购商和供应链不利.然后,分别针对报童及垄断环境,进一步分析了双源采购拍卖下的订货分散程度、信息价值和双源采购价值,发现,订货分散程度与供应风险及两个获胜者的利润率贡献相近程度正相关;高成本获胜者比成本较低者索取更高的单位信息租金,导致不对称信息下的订货分散程度比对称信息下低;供应风险越高或投标人数越多时,双源采购价值越大.     

具有高投标成本的多属性逆向拍卖博弈模型

越来越多像GE这样的大型企业在利用多属性逆向拍卖选择新的供应商采购产品时,通常会设定较高的固定投标成本。针对此情况,建立了三阶段的非合作博弈模型,并利用求解子博弈纳什均衡策略的方法,推导出了供应商的最优投标价格。并得到以下两个主要结论:一是供应商的最优投标策略是按照生产产品真实的质量和交货期进行投标,且投标价格为最优投标价格;二是采购商的最优策略是选择投标价格最高的供应商作为拍卖获胜者,这一违反直觉的结论。这是合理的,因为投标价格最高的供应商也是类型最优的供应商,也即投标质量和投标交货期组合最优的供应商。最后,利用数值实验验证了模型的有效性,并显示出设定相对较高的固定投标成本对采购商来说是有利的。     

基于Cobb-Douglas效用函数的多属性采购拍卖

在多属性采购拍卖的实践中,利润和赢得合同对供给者来说具有不同的重要性.假设供给者使用Cobb-Douglas效用函数对利润和赢得合同的重要性程度进行权衡,在第一评分拍卖及第二评分拍卖下获得了供给者的均衡投标策略和采购者的期望效用,并对采购者的期望效用进行了比较.结果表明供给者对被采购物品的质量选择只与自己的成本参数和打分函数有关;当供给者越看重获取采购合同,采购者的期望效用越高;当采购者只能使用效用函数打分时,如果供给者更看重利润,采购者应该采用第二评分拍卖节约采购成本,否则使用第一评分拍卖.     

外包环境下考虑产品质量的OEM采购战略决策

产品质量是业务外包中的关键问题,同时也是决定企业采购战略选择的重要变量。研究了生产两种替代性产品的制造商的采购战略选择问题,并讨论了不同采购战略对于供应商产品质量决策的影响。考虑制造商可以选择单源策略或者双源策略,并讨论了在四种情形下供应商和制造商的战略互动: 单源策略下,制造商可以选择分享供应商的质量投资或不分享供应商的质量投资; 双源策略下,两个供应商可以选择合作质量决策或者竞争质量决策。研究发现,一个合适的质量投资分享比例能使得与单个供应商合作战略成为制造商的占优选择; 如果制造商不愿意分享或者不愿意分享足够多的质量投资,当双源采购成本足够小时,开发两个竞争性供应商成为制造商的占优策略。对于双源采购策略,还讨论了制造商分享两个供应商质量投资的采购战略,并验证了当分享比例和双源采购成本足够小时,该战略成为制造商的唯一占优选择。另外,当制造商选择双源采购战略时,应避免供应商合作质量决策,因为供应商的质量合谋将会通过提供劣质产品而抽取更多的制造商利润。     

基于多属性逆向拍卖的博弈分析

对只有一个采购商和多个供应商之间进行的单轮多属性逆向拍卖建立了非合作博弈模型,分析得出投标具有最高质量和最短交货期属性的供应商能够获得最大利润,同时能够给采购商带来最大剩余.因此采购商并不会根据最低投标价格,而是根据投标质量和交货期的最优组合来选择新的供应商.然后,把投标价格看作投标质量和交货期的函数,推导出了供应商的最优投标价格策略,并进一步推出纯子博弈纳什均衡策略.最后,通过算例验证了模型的有效性,并指出采购商在利用多属性逆向拍卖进行采购之前,应该对供应商资格进行审核来决定最后能够参与到拍卖中的供应商数目.     

价格相依随机需求下的逆向拍卖采购与定价联合决策

研究价格相依随机需求下零售商的逆向拍卖采购与定价联合决策问题。假定零售商首先确定一个采购合同,然后供应商投标,通过逆向拍卖选取一个获胜的供应商,由该供应商确定采购量并传递给零售商,同时零售商做定价决策影响其需求,目标是寻求一个最优的采购与定价策略以最大化零售商的期望利润。对于一般的随机需求函数,引进期望销售弹性这一新的概念并利用其性质证明零售商的期望收益(不包括采购费用)是采购量的凹函数,从而得到其最优的采购与定价策略。特别地,对正态需求分布情形给出了零售商的采购量和利润函数的解析表达式并进行数值分析。     

考虑供应风险和生产成本不确定性的供应链动态决策研究

考虑到供应风险和生产成本的不确定性,本文研究了买方或卖方实施努力既可能改善供应可靠性,同时又可能降低生产成本的供应链最优决策问题。分别构建了制造商努力和供应商努力的两阶段动态决策模型。分析了提升供应可靠性和降低成本的概率对两种模型中的最优采购数量、最优努力程度和上下游期望收益以及供应链期望收益的影响。同时在两种模型的比较中发现,制造商的最优努力与供应商的最优努力之间的差异与收益分享系数有关。相同努力效果下,制造商努力时的最优采购数量总是不小于供应商努力时的最优采购数量。相比供应商努力,制造商努力更有利于增加其自身的期望收益。然而,供应商以及整个供应链的期望收益却可能在供应商努力时更高。     

存在信息更新时的双源采购和后备生产结合策略研究

在现实的采购运作中,双源采购和后备生产是两种最常见的风险应对策略。本文在考虑信息更新的情况下,探讨了一个两阶段动态采购决策模型：第一阶段,制造商向存在供应风险的一个或两个主供应商订货;第二阶段,制造商根据主供应商风险信息的更新,决定是否向供应可靠但价格较高的后备供应商订货。本文得到了两阶段的最优采购策略,分析发现,当固定采购成本较低时：若潜在市场需求较小,双源采购将排斥后备生产;若潜在市场需求较大,双源采购和后备生产共存;若潜在市场需求适中,后备生产可能排斥双源采购,两者也可能共存。特别地,在潜在市场需求适中时,可靠性改进概率的增大或后备供应商生产成本的降低,将使后备生产趋于排斥双源采购;反之,可靠性改进概率的减小、固定采购成本的降低或后备生产成本的增加,将使两者趋于共存。     

考虑再谈判的网上服务采购多属性拍卖研究

针对在线服务外包，研究了供应商投标服务方案（体现服务质量）和价格的买方决定制多属性采购拍卖，分析了交易双方关于服务内容的再谈判对供应商投标均衡、买方初始服务内容决策和各方期望利润的影响。结果表明，无再谈判情形下，供应商的服务质量投标均衡和信息租金都随初始服务内容递增；而有再谈判情形下，尽管买方对服务质量的评标权重随初始服务内容递增，但供应商服务质量、信息租金及买方期望利润都不受初始服务内容影响。换言之，初始服务内容对采购项目的规制作用被再谈判完全替代。不仅如此，相较于无再谈判情形，再谈判的存在能够激励供应商提供更高的服务质量，并促成更多的服务内容成交，最终使买方、获胜供应商和交易平台都获得更高期望利润。     

Reverse Auctions to Innovate Procurement Processes: Effects of Bid Information Presentation Design on a Supplier's Bidding Outcome

Information technologies (ITs) are being used to innovate various procurement processes. This research study focuses on the supplier‐side effects of IT design choices to conduct reverse auctions, which are increasingly used to procure a wide range of products and services. IT–enabled reverse auctions enhance supplier participation across geographical boundaries, leading to more efficient pricing. However, there are growing concerns about the adverse effects of IT–enabled reverse auctions on a supplier's performance. Supplier‐side issues are gaining prominence in the reverse auction literature and are critical for the long‐term success of reverse auctions. Therefore, we focus on suppliers’ bidding outcomes and assess how the design of an IT–enabled reverse auction facilitates the auction bidding outcomes of participating suppliers. Specifically, we examine the effects of two types of bid information presentation design—full price visibility and partial price visibility—on supplier's auction bidding outcomes, across auctions with different cost certainty and suppliers bargaining power vis‐à‐vis the buyer. The results of this study contribute new knowledge about the ways to use IT for creating effective auction designs and innovating procurement through auctions to enhance both the buyer's and suppliers’ performance. We present the detailed theoretical contributions of our study and discuss the managerial implications for designers of reverse auctions.      

Split‐Award Procurement Auctions—Can Bayesian Equilibrium Strategies Predict Human Bidding Behavior in Multi‐Object Auctions?

We analyze if and when symmetric Bayes Nash equilibrium predictions can explain human bidding behavior in multi‐object auctions. We focus on two sealed‐bid split‐award auctions with ex ante split decisions as they can be regularly found in procurement practice. These auction formats are straightforward multi‐object extensions of the first‐price sealed‐bid auction. We derive the risk‐neutral symmetric Bayes Nash equilibrium strategies and find that, although the two auction mechanisms yield the same expected costs to the buyer, other aspects of the two models, including the equilibrium bidding strategies, differ significantly. The strategic considerations in these auction formats are more involved than in single‐lot first‐price sealed‐bid auctions, and it is questionable whether expected utility maximization can explain human bidding behavior in such multi‐object auctions. Therefore, we analyzed the predictive accuracy of our equilibrium strategies in the laboratory. In human subject experiments we found underbidding, which is in line with earlier experiments on single‐lot first‐price sealed‐bid auctions. To control for regret, we organize experiments against computerized bidders, who play the equilibrium strategy. In computerized experiments where bid functions are only used in a single auction, we found significant underbidding on low‐cost draws. In experiments where the bid function is reused in 100 auctions, we could also control effectively for risk aversion, and there is no significant difference of the average bidding behavior and the risk‐neutral Bayes Nash equilibrium bid function. The results suggest that strategic complexity does not serve as an explanation for underbidding in split‐award procurement auctions, but risk aversion does have a significant impact.     

ASSESSING SOCIAL COSTS OF INEFFICIENT PROCUREMENT DESIGN

This paper considers the social costs implied by inefficient allocation of contracts in a first‐price, sealed‐bid procurement auction with asymmetric bidders. We adopt a constrained (piecewise linear) strategy equilibrium concept and estimate the structural parameters of the bidders' distribution of costs. We estimate social costs defined as the predicted cost difference between the winning firm and the most efficient bidding firm. We also compare the expected procurement costs under two different auction formats. The data is collected from procurement auctions of road painting in Sweden during 1993–1999. The results indicate that the social costs of inefficient contract allocation is about 2% of total potential production cost and that an efficient second‐price auction would lower the expected procurement cost by 2.5%. (JEL: D44, H57, C15)     

Push or Pull? Auctioning Supply Contracts

Consider a buyer, facing uncertain demand, who sources from multiple suppliers via online procurement auctions (open descending price‐only auctions). The suppliers have heterogeneous production costs, which are private information, and the winning supplier has to invest in production capacity before the demand uncertainty is resolved. The buyer chooses to offer a push or pull contract, for which the single price and winning supplier are determined via the auction. We show that, with a pull contract, the buyer does not necessarily benefit from a larger number of suppliers participating in the auction, due to the negative effect of supplier competition on the incentive of supplier capacity investment. We thus propose an enhanced pull mechanism that mitigates this effect with a floor price. We then analyze and compare the outcomes of auctions for push and (enhanced) pull contracts, establishing when one form is preferred over the other based on the buyer's profits. We also compare our simple, price‐only push and pull contract auctions to the optimal mechanisms, benchmarking the performance of the simple mechanisms as well as establishing the relative importance of auction design and contract design in procurement auctions.     

An Analysis of Scoring and Buyer‐Determined Procurement Auctions

In procurement auctions, the object for sale is a contract, bidders are suppliers, and the bid taker is a buyer. The suppliers bidding for the contract are usually the current supplier (the incumbent) and a group of potential new suppliers (the entrants). As the buyer has an ongoing relationship with the incumbent, he needs to adjust the bids of the entrants to include non‐price attributes, such as the switching costs. The buyer can run a scoring auction, in which suppliers compete on the adjusted bids or scores, or, he can run a buyer‐determined auction, in which suppliers compete on the price, and the buyer adjusts a certain number of the bids with the non‐price attributes after the auction to determine the winner. Unless the incumbent has a significant cost advantage over the entrants, I find that the scoring auction yields a lower average cost for the buyer, if the non‐price attributes are available. If the non‐price attributes are difficult or expensive to obtain, the buyer could run a buyer‐determined auction adjusting only the lowest price bid.     

On E‐Auctions for Procurement Operations

Electronic auctions have revolutionized procurement in the last decade. In many situations, they have replaced negotiations for supplier selection and price setting. While they have often greatly reduced transaction costs and increased competition, they have also encountered problems and resistance from suppliers resenting their intrusion on cooperative supplier/buyer relationships. In response to these issues, procurement auctions have evolved in radical new directions. Buyers use business rules to limit adverse changes. Some procurement auctions allow bidders to offer variants in the specifications of products to be supplied. Most important, some suppliers are allowing bidders to bid on packages of items, not just individual items. This tends to change procurement auctions from zero‐sum fights over supplier profit margins to win‐win searches for synergies. These changes have opened up many new research areas. Researchers are trying to improve how to deal with the computational issues involved in package auctions and to analyze the new auctions forms that are evolving. In general, equilibrium incentives are not known, and dealing with ties in package auctions is an issue. Computer scientists are analyzing the use of computerized bidding agents. Mechanisms that combine auctions with fixed buy prices or with negotiations need to be analyzed.     

Sourcing Decisions with Competitive Suppliers and Imperfect Information

Manufacturers often must choose between outsourcing and producing internally. This choice is complex and influenced by a variety of factors, including the costs and capabilities of the potential suppliers. In addition, if the manufacturer outsources, he must design the sourcing process. We study the manufacturer's outsourcing decision, with a focus on the impact of the sourcing process on that decision. We consider a setting in which the manufacturer has imperfect information regarding the suppliers' costs and capabilities, and we assume that the manufacturer uses a two‐stage sourcing process. The first stage is the qualification stage, in which the manufacturer seeks to reduce the uncertainty regarding the suppliers' capabilities. The second stage is the supplier selection stage, in which the manufacturer selects among the qualified suppliers on the basis of price. We first characterize the optimal design of the two‐stage process, and then consider the outsourcing decision. We demonstrate several trade‐offs. Vertical integration enables the manufacturer to reduce uncertainty and extract all of the profits of production. However, outsourcing enables the manufacturer to take advantage of the (potentially) lower costs and higher capabilities of the suppliers, particularly if competition between suppliers can be encouraged. We find that the manufacturer is more likely to vertically integrate when the warranty cost and the cost of exerting effort during qualification are large, and when there is significant uncertainty regarding the suppliers' capabilities. The manufacturer is more likely to outsource when the suppliers' costs (capabilities) are low (high), and when the number of suppliers is large.