中国证券市场股票回购的可操作性探索

股票回购作为中国证券市场新的资本运作方式,正为许多上市公司所接受,尤其是在当前世界经济低迷时期,更被许多上市公司所采用。在进行该资本运作时,应把握时机,熟悉其操作性,并加强对操作方式的监督与管理。     

Reputation and Mechanism Choice in Procurement Auctions: An Experiment

We experimentally study the role of reputation in procurement using two common mechanisms: price‐based and buyer‐determined auctions. While buyers are bound to buy from the lowest bidder in price‐based auctions, they can choose between bidders in buyer‐determined auctions. Only the latter buyers can consider the reputation of bidders. We find that bidders supply higher quality in buyer‐determined auctions leading to higher market efficiencies in these auctions. Accordingly, buyers prefer the buyer‐determined auction over the price‐based auction, while only half of the bidders do so. A more detailed analysis of buyers' and bidders' behavior and profits provides insights into their mechanism choice.     

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.     

日语对话中逆接表现的研究——以[ケド]为中心

说到逆接关系的日语接续词,主要起着连接两个内容互相矛盾的事项的作用。即从前项看,后项内容的展开多悖于前项内容,后项是“非顺接的结果”或“与预测相异”。也就是中文当中常用的“虽然……但是……”。在该类词语中,常用词主要有[ガ][けど][のに][せに]等等。本文以[けど]为中心,以[女性のことは职场编],[男性のことは职场编]及[日本语の谈话の构造分析]为资料,对[けど]一词的的用法做出准确细致的分析,指出[けど]在对话中的各种不同的用法。     

基于拍卖机制的灾害多主体合作搜救仿真研究

本文通过多主体仿真,用改进后的截断性莱维游走模型(Truncated Lévy walks)对搜索过程进行模拟,研究灾害为"极严重"、"严重"、"普通"三种情景下,搜救队伍之间基于分布式拍卖机制的合作方案对救援效果的影响,以某滑坡灾害频发地区为例进行仿真,结果表明:基于该合作机制的救援方案同比提高伤员相对生存率8.0%-14.5%,伤员救出比例同比提高7.4%-16.7%,各掩埋点平均救援完成时间同比减少25%-26.7%;与知名的F-Max-Sum算法相比,性能并无逊色,并且计算过程复杂度低,更适用于搜救队伍之间的合作;对救援方案的鲁棒性和敏感度分析还表明,搜索半径的变化对救援效率具有显著影响,搜救队伍合作范围的扩大并不会对救援效率有明显影响;掩埋点限定的挖掘时间和游走模型中最大转动角度两个参数都存在最优值,当达到最优值时,可使整体救援效率最高。     

Computing monotone disjoint paths on polytopes

The Holt-Klee Condition states that there exist at least d vertex-disjoint strictly monotone paths from the source to the sink of a polytopal digraph consisting of the set of vertices and arcs of a polytope P directed by a linear objective function in general position. The study of paths on polytopal digraphs stems from a long standing problem, that of designing a polynomial-time pivot method, or proving none exists. To study disjoint paths it would be useful to have a tool to compute them. Without explicitly computing the digraph we develop an algorithm to compute a maximum cardinality set of source to sink paths in a polytope, even in the presence of degeneracy. The algorithm uses a combination of networks flows, the simplex method, and reverse search. An implementation is available.     

债券发行的单一价格和多种价格招标的比较

债券的发行一般采用单一价格机制和多种价格机制两种招标形式。为了比较这两类拍卖机制的经济效率,本文通过模拟实验的方法,分析了两类招标机制的效率差异。我们发现,从长期来看,单一价格招标要优于多种价格招标。与此同时,多种价格招标机制作为短期的政策调控手段是可行的,但如果作为一种长期政策则不太合适。     

我国中小型外贸企业发展电子商务的B2B模式分析

讨论外贸电子商务中,中小型外贸企业利用互联网技术为手段,进行电子商务B2B模式交易,分析我国中小型外贸企业在B2B交易中遇到的现实问题及其应对策略。     

Implementing reverse mentoring to address social isolation among older adults

ABSTRACT

Reverse mentoring is a means to address the social work Grand Challenge of social isolation. Among older adults, reverse mentoring can improve social connection by increasing the digital competence of older adults so they can use technology for social benefit, and by facilitating intergenerational connections with young adult mentors. In this paper, reverse mentoring is examined within an intergenerational program that serves older adults and utilizes the native technological knowledge and skills of young adults who mentor older adult participants. Qualitative data were collected through young adult mentor logs of each session, and through open-ended questions on the post-surveys collected from older adults and young adult mentors. Qualitative analysis revealed three themes related to social connection: (1) an increased sense of self-efficacy for older adults as they build confidence in technological use, and for young adults as they develop leadership skills through mentoring, (2) the breaking down of age-related stereotypes, and (3) intergenerational engagement and connection. The findings demonstrate that reverse mentoring can be used in various settings to decrease the social isolation of older adults by developing intergenerational connections and increasing older adult usage of technology.     

权利形态转化问题探究

权利状况是一个国家法治化程度的重要指标,在由道德权利、法律权利和实有权利三者组成的权利形态体系中,位居金字塔顶部的实有权利更有实际意义和现实价值,因此如何实现权利形态正向转化最终达到实有权利便成了权利转化追求的目标,而权利形态逆向转化也是权利转化中的普遍现象,社会的物质因素和观念因素、权利设定的主体因素以及权利的政策性倾向因素等共同决定权利形态最终所处的实际状态。