略论高科技项目投资风险的模糊综合评判

高科技项目具有高风险、高收益、高增长潜力的特点。如何较好地评价项目风险从而减少投资过程中的不确定性已成为高科技项目成败的关键。基于此,该文通过对高科技投资项目风险因素的深入分析,运用模糊数学的理论和方法,建立起一套较科学的风险评价体系。     

Bounding Analysis as an Inadequately Specified Methodology

The bounding analysis methodology described by Ha-Duong et al. (this issue) is logically incomplete and invites serious misuse and misinterpretation, as their own example and interpretation illustrate. A key issue is the extent to which these problems are inherent in their methodology, and resolvable by a logically complete assessment (such as Monte Carlo or Bayesian risk assessment), as opposed to being general problems in any risk-assessment methodology. I here attempt to apportion the problems between those inherent in the proposed bounding analysis and those that are more general, such as reliance on questionable expert elicitations. I conclude that the specific methodology of Ha-Duong et al. suffers from logical gaps in the definition and construction of inputs, and hence should not be used in the form proposed. Furthermore, the labor required to do a sound bounding analysis is great enough so that one may as well skip that analysis and carry out a more logically complete probabilistic analysis, one that will better inform the consumer of the appropriate level uncertainty. If analysts insist on carrying out a bounding analysis in place of more thorough assessments, extensive analyses of sensitivity to inputs and assumptions will be essential to display uncertainties, arguably more essential than it would be in full probabilistic analyses.     

Estimating the First- and Second-Order Parameters of a Heavy-Tailed Distribution

This paper suggests censored maximum likelihood estimators for the first‐ and second‐order parameters of a heavy‐tailed distribution by incorporating the second‐order regular variation into the censored likelihood function. This approach is different from the bias‐reduced maximum likelihood method proposed by Feuerverger and Hall in 1999. The paper derives the joint asymptotic limit for the first‐ and second‐order parameters under a weaker assumption. The paper also demonstrates through a simulation study that the suggested estimator for the first‐order parameter is better than the estimator proposed by Feuerverger and Hall although these two estimators have the same asymptotic variances.     

Estimation of the intercept parameter for linear regression model with uncertain non-sample prior information

This paper considers alternative estimators of the intercept parameter of the linear regression model with normal error when uncertain non-sample prior information about the value of the slope parameter is available. The maximum likelihood, restricted, preliminary test and shrinkage estimators are considered. Based on their quadratic biases and mean square errors the relative performances of the estimators are investigated. Both analytical and graphical comparisons are explored. None of the estimators is found to be uniformly dominating the others. However, if the non-sample prior information regarding the value of the slope is not too far from its true value, the shrinkage estimator of the intercept parameter dominates the rest of the estimators.     

Measuring the impact of prices on inequality: With applications to Thailand and Korea

This paper develops a new methodology to compute social cost of living indices. These indices indicate whether or not price changes have a favourable (or unfavourable) impact on the welfare of the poor. The indices are derived on the basis of two alternative classes of social welfare functions. The methodology developed in the paper is applied to compute social cost of living indices for Thailand and Korea. The empirical results show that changes in prices have generally affected the poor more adversely than the non-poor.     

Local model uncertainty and incomplete-data bias (with discussion)

Summary.  Problems of the analysis of data with incomplete observations are all too familiar in statistics. They are doubly difficult if we are also uncertain about the choice of model. We propose a general formulation for the discussion of such problems and develop approximations to the resulting bias of maximum likelihood estimates on the assumption that model departures are small. Loss of efficiency in parameter estimation due to incompleteness in the data has a dual interpretation: the increase in variance when an assumed model is correct; the bias in estimation when the model is incorrect. Examples include non-ignorable missing data, hidden confounders in observational studies and publication bias in meta-analysis. Doubling variances before calculating confidence intervals or test statistics is suggested as a crude way of addressing the possibility of undetectably small departures from the model. The problem of assessing the risk of lung cancer from passive smoking is used as a motivating example.     

改进的对星载SAR的应答式欺骗干扰

分析了对星载SAR的应答式欺骗干扰,并对其进行了改进。改进后的干扰方式只需从敌方雷达信号中估计信号的多普勒斜率、雷达飞行速度和脉冲重复频率,并且实现简单。讨论了参数估计精度对干扰信号成像的影响,结果表明该方法对参数精度要求不高。指出了多普勒斜率估计的方法,通过仿真实验验证了理论分析的正确性和方法的有效性,这对欺骗干扰信号生成算法和欺骗干扰的实现具有重要意义。     

Getting the offer: Sex discrimination in hiring

The hiring process is currently the least understood aspect of the employment relationship. It may be the most important for understanding the broad processes of stratification with allocation of demographic groups to jobs and firms. The lack of knowledge is due to difficulty of assembling data on the processes that occur at the point of hire. Against this background we analyze data on all applicants to positions in one of the largest Scandinavian banks in 1997–1998, providing what we believe to be the first study using applicant pool data and information about extended offers in a private-sector European firm, adding to the record of about half a dozen such U.S. studies. The hiring agents in the organization are fully conscious and concerned about the nonconscious biases and gender schemas they carry when making hiring decisions. Their effects on hiring are considered to be beyond dispute: women are at a clear disadvantage. For actual hiring practices we found that the opposite is true: women are not at a disadvantage and may even be at an advantage in getting offers. Two organizational practices may lead to female advantage. The hiring agents had been educated about the role of nonconscious biases, which perhaps mitigated their effects. But they had also been instructed to search actively for qualified females in the applicant pool. With no qualified females in the first pass, they go through the pool a second and third time hoping to find one. We discuss reasons why the interpretations and meanings the hiring agents attribute to the hiring process are at odds with what actually occurs.     

行为金融学理论述评

20世纪80年代以来,大量的金融研究与市场异象对传统资本市场理论提出了挑战。行为金融理论在整合多学科研究成果,特别是心理学研究的基础上,从投资者的实际决策行为出发,分析与解释金融市场。通过文献研究,文章回顾了有关行为金融学的基本理论与研究,包括前景理论及其他相关理论的发展。此外,对国内有关行为金融学研究特点进行总结分析,并对其今后研究发展提出了设想。     

利益内部化与成本外部化的合成陷阱

通过社会生活中常见的一些事例的分析,归纳出经济个体具有利益内部化与成本外部化的双重倾向,进而形成合成陷阱,吞噬公共福利。合成陷阱产生的机理和演化升级是源自制度缺陷,消解合成陷阱的路径是还权弱势。