Repeated Price Search

Consumers check few sites in online purchases. Previous research and experiments we perform demonstrate that consumers can not calculate the optimal strategy for price search. They use heuristics whose performance is better than random and less than optimal. To investigate online price search performance we survey student online textbook purchases. Students achieve good performance because they start with a good strategy and online market organization of marketplace and meta-search sites. An important factor is that algorithms at sites searched perform calculations that reduce the computational complexity of the search.     

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.     

Implications of a Reserve Price in an Agent-Based Common-Value Auction

Auction sellers can use a reserve price to require a minimum bid before items are sold. Theoretical and experimental research has tested the influence of a reserve price in an independent private values auction, but little focus has been given to the influence of a reserve price in a first-price common-value auction. We establish an agent-based first-price common-value auction to determine the impact of the reserve price with two buyers and with three buyers. An agent-based approach to this problem is both a unique contribution to the literature and appropriate since finding analytical solutions with common-value auctions is difficult. The agent-based model approach also allows us to consider buyers that have non-symmetric bid functions. Furthermore, we introduce a combination of numerical integration techniques with a new particle swarm learning algorithm. The buyers in the model choose their expected-net-revenue-maximizing bid price, and sellers choose their expected-revenue-maximizing reserve price. In the two-buyer and three-buyer auction, a reserve price increases the equilibrium winning bid price, decreases the probability that the item is sold, and increases the seller’s expected revenue. A reserve price in a two-buyer auction increases the winning bid price more than including an additional buyer in the auction with no reserve price. However, due to only receiving a salvage value when the item does not sell in the auction, the seller’s expected revenue is higher in the three-buyer first-price common-value auction without a reserve price than in the two-buyer auction with a reserve price.     

Ad Hoc网络中基于重复博弈的攻击预测模型

大多数入侵检测系统预测攻击行为能力较弱,不能实时主动地响应攻击。针对该问题,提出一种基于重复博弈的攻击预测模型。通过建立入侵者和入侵检测系统之间的阶段博弈模型,给出阶段博弈的纳什均衡,并求出重复博弈情况下的子博弈精炼纳什均衡。使用QRE模型预测攻击者和防御者在博弈阶段1~t中选择各种策略的概率,利用Gambit分析得出预测结果。基于GloMoSim的仿真结果表明,相比纳什均衡模型,QRE均衡模型的预测效果更好。     

基于XGBoost算法分析影响二手车拍卖价的因素

随着国家对二手车市场的进一步开放和"互联网+"的大力推广,C2B模式下的二手车拍卖网站快速发展。二手车市场被认为是汽车产业链上的最后一片蓝海。近年来,很多投资纷纷入驻二手车行业。笔者根据车系、车况等级、车龄、行驶里程、新车指导价、排放标准、过户情况和拍卖人数等特征,构建了基于XGBoost算法的二手车拍卖价格预测模型,分析了各特征对拍卖价格的影响。     

一种基于价格感知的Ad Hoc网络按需路由协议

在无线Ad Hoc网中,判断路径优劣的度量参数主要有跳数、延迟、能量等,常常导致过度使用中心节点,引起网络拥塞.针对这一问题,提出了一种基于价格感知的多目标优化按需路由协议.该协议以价格为主要度量指标,采用分层的体系结构以获得全网一致的拓扑视图,消除分布式预测带来的不一致性.仿真结果表明,该协议提高了分组投递率并降低了端到端平均时延,在动态移动环境下具有较好的稳定性.     

On the Stability of Generalized Second Price Auctions with Budgets

The Generalized Second Price (GSP) auction used typically to model sponsored search auctions does not include the notion of budget constraints, which is present in practice. Motivated by this, we introduce the different variants of GSP auctions that take budgets into account in natural ways. We examine their stability by focusing on the existence of Nash equilibria and envy-free assignments. We highlight the differences between these mechanisms and find that only some of them exhibit both notions of stability. This shows the importance of carefully picking the right mechanism to ensure stable outcomes in the presence of budgets.     

拍卖代理技术在拍卖系统中的应用

介绍了拍卖代理的工作原理、基本策略及实现方法,分析了拍卖代理子系统在整个拍卖系统中的位置及与其它子系统的联系.     

强动态Ad Hoc网的拥塞控制:价格协作和滚动优化

Ad Hoc网络存在着无线多跳连接、节点移动这两个本质的特点.前者引起了与固定网络截然不同的信息流竞争新特点,后者导致了网络状态不断发生变化.首先,在采用链路干扰集描述信息流竞争特点的基础上,将小时间段内网络状态不变的拥塞控制问题表达成非线性优化问题;其次,运用基于对偶分解理论的价格协作法PCA(price cooperation approach)求解该优化问题,构建了一个基于链路干扰集的价格框架.同时,运用队列长度监控、邻居集合近似和HELLO捎带信息这3种技术将PCA转化成在实际Ad Hoc网络环境中可实施的协议.另一方面,运用状态检测和滚动优化方法,有针对性地解决Ad Hoc网络状态不确定时变性带来的问题,相应地设计了自适应优化策略AOS(adaptive optimization strategy).MATLAB仿真结果表明,AOS策略比PCA对网络状态的变化具有更好的自适应性能.NS仿真实验结果表明了PCA和PCA AOS在几乎所有的仿真场景和移动环境下,在重要的性能指标,包括吞吐量、丢包率、公平性等方面,都比TCP,ATCP和ATP有了明显的改进.     

无收据的密封式电子拍卖协议

提出一个高效的无收据密封式电子拍卖协议,无收据的意义是在协议进行过程中没有可以作为“收据”的公开数据,从而能够更好地保证竞拍者的安全。与现有的无收据密封式电子拍卖协议相比,该文的协议在竞拍价格变化较大的情况下,效率有很大的提高。     

The Duo-Item Bisection Auction

This paper proposes an iterative sealed-bid auction for selling multiple heterogeneous items to bidders interested in buying at most one item. It generalizes the single item bisection auction (Grigorieva et al. Econ Theory, 30:107–118, 2007) to the environment with multiple heterogeneous items. We focus on the case with two items for sale. We show that the auction elicits a minimal amount of information on preferences required to find the Vickrey–Clark–Groves outcome (Clarke, Public Choice, XI:17–33, 1971; Groves, Econometrica, 61:617–631, 1973; Vickrey, J Finance, 16:8–37, 1961), when there are two items for sale and an arbitrary number of bidders.     

完全竞争均衡的频谱双向拍卖机制研究

频谱拍卖可以通过市场竞争的方式实现资源的优化配置,从而缓解日益严重的频谱资源危机,已经受到了广泛关注.但现有的频谱拍卖研究重点考虑了如何在一般物品拍卖的基础上实现频谱的空间复用,以提高利用率,却忽视了频谱拍卖市场规模过小,存在盲目报价等问题,极易导致最终成交价与频谱实际价值相偏离.为了解决该问题,提出了完全竞争均衡的频谱双向拍卖机制(ComDSA).该机制首先将参与者之间的多人博弈抽象为参与者与市场间的双人博弈,随后引入市场类型概率,采用海萨尼转换将其转换为完全信息博弈.最后,引入了连续竞价模型,通过参与者的多轮反复竞价,最终使成交价达到完全竞争均衡水平.理论分析与仿真实验结果表明,设计的拍卖机制在实现完全竞争均衡的基础上,有效提高了频谱的空间复用率和拍卖成交率.     

一种安全的多属性拍卖模型

网络拍卖不仅成为电子商务不可分割的部分,而且是自治Agent和多Agent系统(MAS)技术的重要应用领域.同时,拍卖作为一种有效的资源分配形式,在联盟生成等MAS问题中有着重要的应用,因而受到学者们越来越多的关注.拍卖的安全性、隐私性特征是拍卖研究的重要方面.给出了一个一般的多属性拍卖模型和一个安全的多属性拍卖协议——SVAMA协议,并证明了SVAMA的一些重要性质,如Strategy-proof等.并与已有的多属性拍卖和使用的安全方法进行了比较,部分改进了David,Brandt等人的工作.