The empirical analysis of the -bilateral optimized combinatorial auction model

This study proposes a new and highly efficient dynamic combinatorial auction mechanism—the N-bilateral optimized combinatorial auction (N-BOCA). N-BOCA is a flexible iterative combinatorial auction model that offers more optimized trading for multiple suppliers and purchasers in the supply chain than one-sided combinatorial auction. We design the N-BOCA model from the perspectives of market architecture, trading rules, and decision strategy for winner determination, the decision strategy for winner determination needs flexible optimization modeling capability. Thus rule-based reasoning was applied for reflecting the flexible decision strategies. We also show the viability of N-BOCA through Paired Samples T-test experimentation. It shows that N-BOCA yields higher purchase efficiency and effectiveness than the one-auctioneer to multi-bidders (1-to-N) combinatorial auction mechanism.     

中国A股公司市盈率、市净率与ROE水平的关系研究

本文利用沪深两市1996年至2002年A股公司的数据,全面系统地研究了ROE水平与市盈率、市净率间的关系,分析了市盈率和市净率作为估值标准的合理性问题.检验结果表明,市净率与ROE水平间是非单调的函数关系,合理地反映了不同ROE水平公司未来业绩、风险和净资产的质量等基本面因素,是理想的估值标准;而市盈率受盈余管理影响很大,不是恰当的估值标准.     

Profit efficiency analysis under limited information with an application to German farm types

Lack of information about technology and prices often hampers the empirical assessment of the profit maximization hypothesis (viz. by measuring the degree of profit efficiency). The non-parametric Data Envelopment Analysis (DEA) methodology can deal with such incomplete information. We exploit the implicit but largely neglected profit interpretation of the DEA model that builds on assumptions of monotone and convex production possibility sets. We show how its embedded assessment of necessary conditions for profit maximization can be strengthened given partial information in the form of monetary sub-cost/-revenue data (that are often easier obtained than the pure quantity data). Finally, we argue that a ‘mix’ efficiency analysis is naturally complementary to such a profit efficiency analysis. An application to German farm types complements our methodological discussion. By using non-parametric statistical tests, we further demonstrate the potential of the non-parametric approach in deriving strong and robust statistical evidence while imposing minimal structure on the setting under study. In particular, we look for significant efficiency variation over regions.     

Trading on Twitter: Using Social Media Sentiment to Predict Stock Returns

Decision making is often based on the rational assessment of information, but recent research shows that emotional sentiment also plays an important role, especially for investment decision making. Emotional sentiment about a firm's stock that spreads rapidly through social media is more likely to be incorporated quickly into stock prices (e.g., on the same trading day it was expressed), while sentiment that spreads slowly takes longer to be incorporated into stock prices and thus is more likely to predict stock prices on future days. We analyzed the cumulative sentiment (positive and negative) in 2.5 million Twitter postings about individual S&P 500 firms and compared this to the stock returns of those firms. Our results show that the sentiment in tweets about a specific firm from users with less than 171 followers (the median in our sample) had a significant impact on the stock's returns on the next trading day, the next 10 days, and the next 20 days. Interestingly, sentiment in tweets from users with fewer than 171 followers that were not retweeted had the greatest impact on future stock returns. A trading strategy based on these findings produced meaningful economic gains on the order of an 11–15% annual return.     

企业管理信息系统与P3、P3e/c数据交换的研究与实现

本文首先讨论P3、P3e/c项目管理软件与企业管理信息系统集成的必要性和重要性,然后详细地介绍了采用RA引擎(OLE对象)技术来实现P3软件与企业管理信息系统的数据交换,以及与P3e/c交互的原理。分析P3、P3e/c在数据组织上的差异,提出解决方案。最后以实例讨论和分析了这种方法在实际系统中的应用。     

TRADE QUOTAS AND BUYER POWER,WITH AN APPLICATION TO THE E.U. NATURAL GAS MARKET

We consider a market in which domestic buyers negotiate contracts with foreign sellers, and explore how trade quotas can help to increase the buyers' countervailing power. We use the Shapley value to describe bargaining power and the distribution of the trade surplus in such a bilateral oligopoly. By exploiting strategic externalities among the buyers, bilateral trade quotas can improve the buyers' bargaining positions. In contrast, aggregate trade restrictions on all buyers' trade never improve buyer surplus. Minimum quotas on imports from fringe suppliers can benefit nonaffected buyers, as these enjoy positive externalities. We apply these insights to the E.U. market for natural gas and show that the effects of trade quotas on E.U. gas importers' power can be significant.     

PREFERENCES FOR REDISTRIBUTION AND PERCEPTION OF FAIRNESS: AN EXPERIMENTAL STUDY

We conduct a laboratory experiment to study how demand for redistribution of income depends on self‐interest, insurance motives, and social concerns relating to inequality and efficiency. Our choice environments feature large groups of subjects and real‐world framing, and differ with respect to the source of inequality (earned or arbitrary), the cost of taxation to the decision maker, the dead‐weight loss of taxation, uncertainty about own pretax income, and whether the decision maker is affected by redistribution. We estimate utility weights for the different sources of demand for redistribution, with the potential to inform modeling in macroeconomics and political economy     

EXPLAINING GIFT‐EXCHANGE—THE LIMITS OF GOOD INTENTIONS

This paper explores the limitations of intention‐based social preferences as an explanation of gift‐exchange between a firm and a worker. In a framework with one self‐interested and one reciprocal player, gift‐giving never arises in equilibrium. Instead, any equilibrium in a large class of multistage games must involve mutually unkind behavior of both players. Besides gift‐exchange, this class of games also includes moral hazard models and the rotten kid framework. Even though equilibrium behavior may appear positively reciprocal in some of these games, the self‐interested player never benefits from reciprocity. We discuss the relation of these results to the theoretical and empirical literature on gift‐exchange in employment relations.     

BOOK TRANSLATIONS AS IDEA FLOWS: THE EFFECTS OF THE COLLAPSE OF COMMUNISM ON THE DIFFUSION OF KNOWLEDGE

We use book translations as a new measure of international idea flows and study the effects of Communism's collapse in Eastern Europe on these flows. Using novel data on 800,000 translations and difference‐in‐differences approaches, we show that while translations between Communist languages decreased by two thirds with the collapse, Western‐to‐Communist translations increased by a factor of 4 and quickly converged to Western levels. Convergence was more pronounced in the fields of applied and social sciences, and was more complete in Satellite and Baltic than in Soviet countries. We discuss how these patterns help us understand how repressive institutions and preferences towards Western European ideas shaped the international diffusion of knowledge.     

Does Formal Education for Older Workers Increase Earnings? — Evidence Based on Rich Data and Long‐term Follow‐up

Governments in Europe, Canada and the USA have expressed an ambition to stimulate education of older. In this paper, we analyse if there are effects on annual earnings of formal education for participants aged 42–55 at the time of enrolment in 1994–95. The analysis explores longitudinal population register data stretching from 1982 to 2007. The method used is difference‐in‐differences propensity score matching based on a rich set of covariates, including indicators of health and labor market marginalization. Our findings underline the importance of long follow up periods and imply positive effects for women, especially so for women with children, and no significant average earnings effects for men. These results differ from earlier studies but are stable to several alternative assumptions regarding unobservable characteristics. Data further indicate that the gender gap in our estimates may stem from differences in underlying reasons for enrolment.