Decision-Making, Time Horizons, and Risk in the Very Long-Term Perspective

Some decisions made today have far-reaching consequences as exemplified by those concerning nuclear power and spent nuclear fuel. The investigation presented here uses a decision theoretic framework in which time horizons and the discounting of negative consequences play significant roles. The results indicated wide variations in the lengths of the planning horizons judged to be adequate not only across a number of activities, including nuclear waste management, but also across groups of subjects (e.g., engineering students, retired people, and nuclear fuel experts). The paper reports typical judgments and correlations between different variables for different groups of subjects. The differences across groups reflect potential sources of conflict, depending in part on different values and different perceptions of more or less uncertain facts. Discounting functions for negative consequences in the future were also established. A range in differences in the speed of discounting were found and illustrated. Furthermore, it was found that substantial proportions in all groups regarded negative consequences related to nuclear waste as nondiscountable. When asked about the effect of time until outcome on acceptable probability of a negative outcome, many subjects used the probability concept in an incoherent way, illustrating the great difficulty in communicating small probabilities in a long-term risk context.     

圆光栅细分误差的动态测量

本文讨论了圆光栅细分误差及其测量,提出了不采用高精度标准件的圆光栅细分误差测量法——时间平均法,并通过实际测试结果证明了时间平均法的可行性。     

一种抗干扰时间闸门电路的设计

针对内插法计数器中存在的寄生脉冲，设计了一种特殊的滞回比较器，这种电路不仅有效地抑制了寄生脉冲干扰，而且可对双阈值带来的时间扩展误差进行补偿，该电路用于脉冲式激光测距，可使距离分辨精度达到±5mm．     

《教育时间学》出版十年反思与前瞻

《教育时间学》出版十年来 ,作者对教育时间学这门形成中的学科的若干基本问题不断反思 ,形成了更为清晰的认识。作者同时认识到 ,教育时间学要成为一门公认的学科 ,还有相当长的路要走 ,作者将团结同道继续努力。     

Estimating stellar-oscillation-related parameters and their uncertainties with the moment method

Summary.  The moment method is a well-known astronomical mode identification technique in asteroseismology which uses a time series of the first three moments of a spectral line to estimate the discrete oscillation mode parameters l and m . The method, in contrast with many other mode identification techniques, also provides estimates of other important continuous parameters such as the inclination angle α and the rotational velocity v _e. We developed a statistical formalism for the moment method based on so-called generalized estimating equations. This formalism allows an estimation of the uncertainty of the continuous parameters, taking into account that the different moments of a line profile are correlated and that the uncertainty of the observed moments also depends on the model parameters. Furthermore, we set up a procedure to take into account the mode uncertainty, i.e. the fact that often several modes ( l ,  m ) can adequately describe the data. We also introduce a new lack-of-fit function which works at least as well as a previous discriminant function, and which in addition allows us to identify the sign of the azimuthal order m . We applied our method to star HD181558 by using several numerical methods, from which we learned that numerically solving the estimating equations is an intensive task. We report on the numerical results, from which we gain insight in the statistical uncertainties of the physical parameters that are involved in the moment method.     

时间数列分析中的加法模型与乘法模型

文章通过实例说明了时间数列分析中加法模型的应用,纠正了一些统计学教材上常见的错误认识和模型的错误使用,对统计教材中统计方法的系统化起到了一定的作用。     

时代主题转换与中国特色社会主义的发展

20世纪80年代末90年代初苏东社会主义国家发生的剧变,使世界社会主义遭受了空前严重的大挫折;但与此同时,中国的改革开放事业,却进入了一个新的发展阶段,开创了社会主义事业的新局面.一个"大挫折",一个"新局面",形成了鲜明的对比.究其原因,关键是我们能够顺应时代潮流的发展,正确分析国际形势和时代特征,并根据中国国情,制定了正确的方针政策.     

Semiparametric Efficient Estimation of the Mean of a Time Series in the Presence of Conditional Heterogeneity of Unknown Form

We obtain semiparametric efficiency bounds for estimation of a location parameter in a time series model where the innovations are stationary and ergodic conditionally symmetric martingale differences but otherwise possess general dependence and distributions of unknown form. We then describe an iterative estimator that achieves this bound when the conditional density functions of the sample are known. Finally, we develop a “semi-adaptive” estimator that achieves the bound when these densities are unknown by the investigator. This estimator employs nonparametric kernel estimates of the densities. Monte Carlo results are reported.     

International Business Cycle Asymmetry and Time Irreversible Nonlinearities

Using tests of time reversibility, this paper provides further statistical evidence on the long-standing conjecture in economics concerning the potentially asymmetric behaviour of output over the expansionary and contractionary phases of the business cycle. A particular advantage of this approach is that it provides a discriminating test that is instructive as to whether any asymmetries detected are due to asymmetric shocks to a linear model, or an underlying non-linear model with symmetric shocks, and in the latter case is informative as to the potential form of that nonlinear model. Using a long span of international per capita output growth data, the asymmetry detected is overwhelmingly consistent with the long standing perception that the output business cycle is characterized by steeper recessions and longer more gentle expansions, but the evidence for this form of business cycle asymmetry is weaker in the data adjusted for the influence of outliers associated with wars and other extreme events. Statistically significant time irreversibility is reported for the output growth rates of almost all of the countries considered in the full sample data, and there is evidence that this time irreversibility is of a form implying an underlying nonlinear model with symmetrically distributed innovations for 15 of the 22 countries considered. However, the time irreversibility test results for the outlier-trimmed full sample data reveal significant time irreversibility in output growth for around one half of the countries considered, predominantly in Northern Europe and North America, and of a form implying a nonlinear underlying model in only a further half of those cases.     

海德格尔的《存在与时间》有“三重困境”吗——与寇鹏程先生商榷

原载于《汕头大学学报》 (人文社科版 ) 2 0 0 3年第 6期的寇鹏程先生的文章《海德格尔〈存在与时间〉的三重困境》 (另见人大复印资料《外国哲学》 2 0 0 4年第 2期 )指出海德格尔的《存在与时间》存在着三重内在的困境。笔者认为 ,“三重困境”的提法有值得商榷的地方 ,这里一一提出质疑