谈英语教学中的实验性研究--对一项写作教学实验的个案分析

通过对一项写作教学实验的个案分析,讨论了英语教学实验中有关被试者的挑选,变量的控制和实验设计方面应注意的问题,并对该项实验研究提出了自己的修改意见.     

企业垂直兼并动因的数量经济分析

对在企业垂直兼并中，当上下游企业分别处于典型的微现市场环境时所具有的不同效果及其动因进行了分析。对企业生产函数分为固定比例和可变比例函数两种情况进行了讨论。     

Bayesian variable selection for longitudinal substance abuse treatment data subject to informative censoring

Summary.  Measuring the process of care in substance abuse treatment requires analysing repeated client assessments at critical time points during treatment tenure. Assessments are frequently censored because of early departure from treatment. Most analyses accounting for informative censoring define the censoring time to be that of the last observed assessment. However, if missing assessments for those who remain in treatment are attributable to logistical reasons rather than to the underlying treatment process being measured, then the length of stay in treatment might better characterize censoring than would time of measurement. Bayesian variable selection is incorporated in the conditional linear model to assess whether time of measurement or length of stay better characterizes informative censoring. Marginal posterior distributions of the trajectory of treatment process scores are obtained that incorporate model uncertainty. The methodology is motivated by data from an on-going study of the quality of care in in-patient substance abuse treatment.     

A Class of Estimators Using Auxiliary Information in Two-Stage Sampling

This paper presents a general class of estimators for the finite population total when the emphasis is laid on the use of two auxiliary variables in a two-stage sampling.     

稀土永磁同步无齿轮曳引机矢量控制变频调速

交流变频调速是当前电力拖动系统的主要发展方向,本文介绍稀土永磁同步无齿轮曳引机电动机磁路结构设计的特点和矢量控制变频调速系统,分析样机性能的实测数据,说明稀土永磁同步无齿轮曳引机矢量控制变频调速具有同步调速范围宽、转矩和转速平稳、效率和功率因数高等优点,是一种高效节能的电梯拖动调速系统。     

数量特征随机化回答模型中的比估计和回归估计方法

本文研究了含辅助信息的数量特征随机化调查的理论与方法.建立和发展了数量特征随机化调查的比估计和回归估计理论与方法.对于给定的人群有限总体,构造了敏感特征指标总体均值的比估计量和回归估计量,证明了本文提出的方法优于Eichhorn BH,HayreLS（1983）和Gupta et al.（2002）提出的方法.Monte-Carlo数值模拟验证了提出方法的有效性.     

Comparing Fits of Latent Trait and Latent Class Models Applied to Sparse Binary Data: An Illustration with Human Resource Management Data

This paper addresses the problem of comparing the fit of latent class and latent trait models when the indicators are binary and the contingency table is sparse. This problem is common in the analysis of data from large surveys, where many items are associated with an unobservable variable. A study of human resource data illustrates: (1) how the usual goodness-of-fit tests, model selection and cross-validation criteria can be inconclusive; (2) how model selection and evaluation procedures from time series and economic forecasting can be applied to extend residual analysis in this context.     

季节性商品的订购策略

讨论了在一个时期内商品的订购价格有折扣，而且该商品的需求量是离散型随机变量的订购问题，得出了使利润最大化的最佳订购量的计算方法。     

Rhotacization and the ‘Beijing Smooth Operator’: The social meaning of a linguistic variable1

Recent sociolinguistic studies on style have focused much attention on the construction of social meaning in situated discursive practices. Despite a general recognition that the linguistic resources used are often already imbued with social meanings, little research has been done on what these meanings may be. Focusing on rhotacization, a sociolinguistic variable in Beijing Mandarin, this article explores its imbued social meanings and sociocultural associations. I demonstrate that rhotacization takes on semiotic saliency through co‐occurrence with key Beijing cultural terms and frequent use in written representations of authentic Beijing‐ness. Furthermore, this feature is associated with the ‘Beijing Smooth Operator,’ a salient male local character type, and is ideologically construed as reflecting its characterological attributes. The findings of this study shed light on the meaning potential of a linguistic variable, rhotacization in this case, which can enhance understanding of the possibilities and constraints for its use and meaning in new contexts.