统计学之我见

一位中国研究生曾经问我,统计学的主要目的是什么?我引用一句毛泽东的话作为回答,那就是“实事求是”。我知道毛泽东在讲这句话时不是针对统计学而言的,但我认为这句话确实概括了统计研究工作的特点和真正目的。“求是”是我们对客观世界某些方面的认识或探索,“实事”要求我们从实际数据出发从而得到这些认识。     

光纤扭转对循环延迟线偏振控制系统特性影响的研究

借助模式耦合理论和矩阵光学的知识,对引入光纤扭转机构后的延迟线偏振控制系统的偏振转换特性进行了分析,推导出了描述该系统偏振特性的琼斯矩阵,得到了光纤扭转对系统偏振特性影响的理论模型。     

以Mn~(2+)催化的α—酮戊二酸振荡反应的研究

本文利用实验中得到的电动势随时间变化的E～t图,研究了α—酮戊二酸(以α—Ke表示)—KBrO_3—H_2SO_4—丙酮(以Act表示)体系的Mn~(2+)催化下的振荡反应及许多因素对振荡反应的影响,根据实验结果及振荡反应的一般机理,探讨了该体系的振荡机理,归纳出振荡反应参数与反应物浓度之间存在的关系式,并对实验现象作了定性的说明。     

近现代贵州苗族服饰文化的变迁

贵州苗族有丰富的服饰文化。近现代以来,贵州苗族服饰文化发生了文化变迁,建国后其服饰文化更是经历了变化、衰落、复兴的曲折过程,表现出顽强的生命力。     

滑稽模仿之法律地位初探——由《馒头》案引发的思考

滑稽模仿在我国的法律地位尚不明确.滑稽模仿能否被认定为合理使用存在理论上的争议.建议将一定的滑稽模仿纳入合理使用的范畴,在具体认定时,综合考虑四个要素:使用的目的和性质、原作的性质,使用的数量、对原作价值和市场的影响.同时应进一步完善关于保护作品完整权的规定.     

The current state of the labor queue: National and regional Evidence

We employ vector autoregressive techniques to determine the current state of the labor queue. Unemployment rate differentials have narrowed in recent years, potentially due to a change in the queue ordering, though a tight labor market and a stable queue would yield similar results. We find no evidence that the queue ordering has changed, which brings into question the resiliency of gains made by minority groups. We employ the same techniques to reveal the state of the queue across geographic regions and find that substantial differences exist across regions, implying variation in the relative labor force status of demographic groups.     

浅谈如何提高大学生英语阅读理解能力兼评《全新版大学英语快速阅读》

阅读理解能力是衡量一个人英语水平的重要因素之一,随着社会的发展和大学英语教学改革的大力推进,我们应当进一步加强对大学生阅读理解能力的培养,扩充他们对词汇量的掌握,并使他们了解相关的文化背景,从而达到提高阅读速度的目的。     

Marginal and association regression models for longitudinal binary data with drop‐outs: A likelihood‐based approach

Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances.     

Population constraints on pooled surveys in demographic hazard modeling

In non-experimental research, data on the same population process may be collected simultaneously by more than one instrument. For example, in the present application, two sample surveys and a population birth registration system all collect observations on first births by age and year, while the two surveys additionally collect information on women’s education. To make maximum use of the three data sources, the survey data are pooled and the population data introduced as constraints in a logistic regression equation. Reductions in standard errors about the age and birth-cohort parameters of the regression equation in the order of three-quarters are obtained by introducing the population data as constraints. A halving of the standard errors about the education parameters is achieved by pooling observations from the larger survey dataset with those from the smaller survey. The percentage reduction in the standard errors through imposing population constraints is independent of the total survey sample size.