一种基于背包理论的有效多轮电子拍卖协议

在目前的密封式电子拍卖中,都没有解决标价瓶颈问题,即有多个投标者同时提交了相同的获胜价位,有些方案仅仅把标价提高,所有的投标者再重新进行拍卖,这样既增加了计算量又增加了通信量,使拍卖效率很低。文章利用多项式的秘密共享和背包理论,给出了一种新的安全有效的电子拍卖方案。     

基于比特承诺的电子拍卖方案

在拍卖过程中如何保护投标者隐私和防止中标者反悔是设计安全电子拍卖系统的关键问题,也是目前网上拍卖系统急需解决的问题。文章利用伪随机数产生理论和比特承诺机制的优点,给出了一个实现随机标价的密封式电子拍卖方案。该方案除了满足投标者匿名、投标价保密、不可否认性、强可验证性等安全要求外,还具有技术简单、通信量小、随机标价、限时强迫兑现等优点。     

一种匿名的高效M＋1电子拍卖

为了实现投标者的身份匿名,给出了一个基于RSA函数的M 1电子拍卖方案,任何投标者不能否认所投的标书,未中标价不会被泄露.该方案执行开标算法至多需要P轮交互,至多2p log2t次模乘法运算,其中P是标价的个数,t是RSA公钥.计算量与投标者的数量无关,方案安全、高效,远高于现有拍卖方案的效率.     

一种保护标价的多属性反向拍卖模型

多属性反向拍卖作为一种电子采购方式已被广泛应用于电子商务中.在大多数拍卖模型中,投标者的标价信息对于拍卖者来说完全公开,在拍卖者和个别投标者共谋情况下,会造成投标者之间的地位不平等,给其他投标者造成经济损失.文中在逼近理想解评标方法和安全多方计算基础上,提出一种保护标价的多属性反向拍卖模型,该模型采用了安全逼近理想解协议,实现标价保密和投标者地位公平,抵御拍卖者与个别投标者的共谋.     

一种保护标价安全的电子拍卖方案

电子拍卖的一个热点问题是保护标价的秘密性，因为存在第三方不可信任或相互勾结．提出了一个实用的保护标价安全的电子拍卖方案，除了中标价以外，它在任何勾结攻击情况下都能保证投标者标价的秘密性，可以公开验证中标价的正确性，效率远远高于最近Brandt提出的方案．其实现只需要O（log2υ）轮通信，其中υ是标价的范围．投标者注册使用数字签名后能保证协议的不可伪造性、抗重放攻击性和不可否认性．协议中使用零知识证明的安全性保证了系统的鲁棒性．     

一个M+1电子拍卖方案的密码学分析

分析了伍前红等人最近提出的M+1电子拍卖方案,指出该方案假设不同投标者的标价不同的前提条件是不能成立的;另一方面,当有多个投标者同时投了最高价或次高价时,协议将不能实现M+1价位电子拍卖（称为结点问题）,因此方案不具有实用价值。给出了解决这一问题的有效算法。     

一个M＋1电子拍卖方案的密码学分析

分析了伍前红等人最近提出的M＋1电子拍卖方案,指出该方案假设不同投标者的标价不同的前提条件是不能成立的;另一方面,当有多个投标者同时投了最高价或次高价时,协议将不能实现M＋1价住电子拍卖（称为结点问题）,因此方案不具有实用价值。给出了解决这一问题的有效算法。     

一种淘汰式无拍卖行的电子拍卖

在所有的封闭式电子拍卖中存在的一个共同的缺陷结点(tie)问题，即几个投标者同时投了最高价，由于存在着结点严重地影响了拍卖的效率。基于shamir的(t，n)门限体制提出了一种淘汰式无拍卖行的匿名电子拍卖，采用无拍卖行且每个投标者的标价在投标者之间分享实现标价的匿名性的同时，提出了一种淘汰式拍卖解决结点问题，从而使拍卖的效率得到了提高。     

一种安全高效的M+1电子拍卖

为了保护电子拍卖过程中投标者的隐私,以及防止投标者中标后反悔,本文利用签名技术和位承诺协议,提出了一个安全高效的M+1匿名拍卖协议。该协议不仅保证了标价的保密性和可验证性,投标者对所投标价的不可否认性和匿名性,而且保证了在整个拍卖过程中,无人可以操纵其他人的投标。即使某一投标者与拍卖代理相互勾结,也不会影响协议的安全性和有效性。     

一种新的基于ECC的电子拍卖协议*

利用椭圆曲线离散对数问题的难解性, 给出了基于椭圆曲线密码体制(elliptic curve cryptosystems)的可验证、安全、高效、密封的M 1价位电子拍卖方案.除了满足所有投标者身份匿名、所有投标者的标价保密、所有未中标者的个人信息不会被泄露等安全要求外,还能抗击恶意投标者对正常拍卖进行的破坏.     

Bidder's strategy under group-buying auction on the Internet

The group-buying auction is a new kind of dynamic pricing mechanism on the Internet. It is a variant of the sellers' price double auction, which makes the bidders as a group through Internet to get the volume discounts, i.e., the more bidders bid, the lower the price of the object being auctioned becomes. In this paper, we analyze the group-buying auction under some assumptions, such as that the independent private values (IPVs) model applies and bidders are risk neutral and symmetric, etc., and build an incomplete information dynamic game model to illustrate the bidders' bidding process. It proves that for the bidders there exists a weakly dominant strategy S, i.e., no matter when a bidder arrives at the auction and what the bidding history is, the highest permitted bid price that is no greater than his value to the object is always his optimal bid price but may not be the unique one.     

Multi-stage sequential uniform price auction mechanism for divisible goods

In this paper, we study the problem of auctioning a kind of continuous homogeneous divisible goods, and present a multi-stage sequential auction mechanism of divisible goods under uniform price. In this mechanism, the auction process is divided into multiple stages, all bidders satisfy the sequential rationality conditions, all bidders are asymmetric, every bidder is allowed to submit a nonincreasing continuous demand function in each round bidding, every bidder’s valuation to per unit of the goods is independent private information, and if a bidder does not obtain the quantity he wants in former stage auction, he still have another opportunity to obtain some quantity in the later stage auction. For this mechanism, we explore the formation process and composition of equilibrium points in each stage auction, and discuss the optimal strategy selection for bidders, then give the detail steps and an application example to show how to implement this multi-stage sequential auction mechanism. The conclusions can be drawn that our auction mechanism is an efficient incentive mechanism, and can effectively reduce many underpricing equilibrium and can yield higher expected income than a single uniform price auction for the auctioneer. It also can avoid the occurrence of failure auction (equilibrium does not exist), and effectively extend and improve the traditional single stage uniform price auction mechanism.     

Two Rules of a Sealed Ceiling Bid and Their Analysis by Mathematical Programming Techniques

Two rules of a sealed ceiling bid for a contract that a firm offering this contract can set are proposed. The rules are such that they encourage the bidders to submit their prices for the contract within a range desirable by the firm so that these prices not to exceed the (unknown to the bidders) price of the bid (the ceiling). It is shown that under certain natural assumptions on the behavior of the bidders, evaluating chances of a firm to award the contract at a price within such a desirable range as a result of the bid conducted in line with the rules is reducible to solving mathematical programming problems on polyhedral sets. It is also shown that under additional assumptions of the same kind, under the proposed rules, the maximum probability to win the bid at a price within the range is higher for each bidder than that under the rule of awarding the contract to a bidder nominated the lowest price. Thus, while serving the interests of the firm, the proposed rules make the bid more attractive to the potential bidders. © 2006 Elsevier Ltd. All rights reserved.     

Strong activity rules for iterative combinatorial auctions

Activity rules have emerged in recent years as an important aspect of practical auction design. The role of an activity rule in an iterative auction is to suppress strategic behavior by bidders and promote simple, continual, meaningful bidding and thus, price discovery. These rules find application in the design of iterative combinatorial auctions for real world scenarios, for example in spectrum auctions, in airline landing slot auctions, and in procurement auctions. We introduce the notion of strong activity rules, which allow simple, consistent bidding strategies while precluding all behaviors that cannot be rationalized in this way. We design such a rule for auctions with budget-constrained bidders, i.e., bidders with valuations for resources that are greater than their ability to pay. Such bidders are of practical importance in many market environments, and hindered from bidding in a simple and consistent way by the commonly used revealed-preference activity rule, which is too strong in such an environment. We consider issues of complexity, and provide two useful forms of information feedback to guide bidders in meeting strong activity rules. As a special case, we derive a strong activity rule for non-budget-constrained bidders. The ultimate choice of activity rule must depend, in part, on beliefs about the types of bidders likely to participate in an auction event because one cannot have a rule that is simultaneously strong for both budget-constrained bidders and quasi-linear bidders.     

Auctions and Differential Pricing: Optimal Seller and Bidder Strategies in Second-chance Offers

The second chance offer is a common seller practice on eBay. It consists of price discrimination against the losing bidder, who is offered an identical item at the value of his or her highest bid. Prior work has shown that, if the goods are private-value goods and price discrimination is certain, rational bidders can anticipate it and accordingly modify their bidding strategies; this results in revenue loss for the seller. This paper hence examines the impact of randomized price discrimination. It examines a similar, more general problem: a seller has k items of the private-value good. They are sold to N bidders in a two-stage game. The first stage is a sealed-bid first-price auction with N bidders. The second stage is a take-it-or-leave-it offer to each of k − 1 losing bidders; randomized between a fixed-price offer and a second-chance offer. Showing that analytic techniques do not provide complete solutions because bidding strategies are not always monotonic increasing, this paper uses genetic algorithm simulations to determine the Bayesian (near-Nash) equilibrium strategies for bidders and sellers, for N = 8 and different values of k. It finds that price discrimination is beneficial to the seller when k is small, as item scarcity increases competition among bidders. The paper’s use of randomized seller strategies and genetic algorithm simulations is unique in the study of the second-chance offer.     

Multiagent System Simulations of Treasury Auctions

This study uses a multiagent system to determine which payment rule provides the most revenue in treasury auctions. The agents learn how to bid using straightforward bid adjustment rules that are based on impulse balance learning. The market model encompasses the when-issued, auction, and secondary markets, as well as bidding constraints for primary dealers. I find that when the number of primary bidders is less than 13 (Canada) the Discriminatory payment rule is revenue superior to the Uniform payment across most market price spreads. When the number of primary bidders is greater than 14 (United States), Uniform payment is revenue superior to Discriminatory payment for all market price spreads. In general, revenue increases with the minimum bid constraint and with the number of primary dealers for Uniform, Average, and Vickrey payment rules.      

Design of online auctions: Proxy versus non-proxy settings

Recent years have witnessed the rapid development of online auctions. Currently, some online auctions, such as eBay, introduce a proxy bidding policy, under which bidders submit their maximum bids and delegate to a proxy agent to automatically outbid other competitors for the top bidder, whereas other online auctions do not. This paper compares these two widely used auction mechanisms (proxy setting and non-proxy setting) and characterizes the equilibrium bidding behavior and the seller's expected revenue. We find the proxy auction outperforms the non-proxy auction in terms of the seller's expected revenue. This dominance result is not prone to the specific bid announcement policy, the bidder's knowledge regarding the number of bidders, the impact of traffic congestion along the bidding process, the number of items sold through the auction, and the existence of a reserve price.We further find that the proxy setting usually fails to sustain the truthful bidding as a dominant strategy equilibrium even if no minimum bid increments are adopted, and the possibility of a low-valuation-bidder dilemma where the low-valuation bidders could be better off if all bidders collude to bid at the last minute. We also discuss the dramatically different equilibrium bidding behaviors under the two auction mechanisms.