高中英语新教材的应用呼唤交际式语言测试

高中英语新教材的应用,使得测试手段的改革势在必行.新教材与目前测试手段的矛盾日益突出,使得交际式语言测试的运用成为必然.科学地运用交际式语言测试,能对英语教学产生较好的反拨作用,从而提高高中英语教学质量.     

假设检验的一个常见误区

文章通过对假设检验的一个常见错误进行了理论分析,指出假设检验的方法只能在一定情况下否定原假设而不能肯定原假设,并提出了设定原假设和备择假设的正确而简明的方法。     

基因工程技术及其在林木培育中的应用

概述了基因工程在国内外林木培育中的应用现状及发展趋势 ,综述了我国十多年来林木在抗虫、抗病、抗逆境、品质改良、育性等基因工程的研究与应用研究取得的一些进展及今后的发展方向。     

当今智力测验面临的问题与争论

智力测验争论的焦点是测验的有效性和公平性。多元智力理论就是为解决这些问题而产生的。但这些争议是由于人们的一些错误观念而产生的 ,而多元智力理论并不能从根本上消除这些争议。     

一种基于RCPT码的渐进图像传输方法

将等级树中的集分割编码器输出的码流分组,根据输出的分组数据对重建图像重要性的不同,传输前采用纠错能力不同的RCPT码保护。在总的码率限制下,采用遗传算法从有限码率集中选择每组数据的RCPT码码率,使接收端恢复的图像失真最小。将等误差保护码率作为遗传算法的初始种群,减少了最优码率集的搜索时间。在二进制对称信道上的仿真结果表明,该渐进图像传输方法实现简单,在高误码率信道条件下恢复图像仍能得到很高的峰值信噪比。     

Computational Forecasting of Wavelet-converted Monthly Sunspot Numbers

Monthly average sunspot numbers follow irregular cycles with complex nonlinear dynamics. Statistical linear models constructed to forecast them are therefore inappropriate, while nonlinear models produce solutions sensitive to initial conditions. Two computational techniques - neural networks and genetic programming - that have their advantages are applied instead to the monthly numbers and their wavelet-transformed and wavelet-denoised series. The objective is to determine if modeling wavelet-conversions produces better forecasts than those from modeling series' observed values. Because sunspot numbers are indicators of geomagnetic activity their forecast is important. Geomagnetic storms endanger satellites and disrupt communications and power systems on Earth.     

Comparison of Separable Components in Different Samples

Abstract.  Imagine we have two different samples and are interested in doing semi- or non-parametric regression analysis in each of them, possibly on the same model. In this paper, we consider the problem of testing whether a specific covariate has different impacts on the regression curve in these two samples. We compare the regression curves of different samples but are interested in specific differences instead of testing for equality of the whole regression function. Our procedure does allow for random designs, different sample sizes, different variance functions, different sets of regressors with different impact functions, etc. As we use the marginal integration approach, this method can be applied to any strong, weak or latent separable model as well as to additive interaction models to compare the lower dimensional separable components between the different samples. Thus, in the case of having separable models, our procedure includes the possibility of comparing the whole regression curves, thereby avoiding the curse of dimensionality. It is shown that bootstrap fails in theory and practice. Therefore, we propose a subsampling procedure with automatic choice of subsample size. We present a complete asymptotic theory and an extensive simulation study.     

Two-stage U-statistics for Hypothesis Testing

Abstract.  A U -statistic is not easy to apply or cannot be applied in hypothesis testing when it is degenerate or has an indeterminate degeneracy under the null hypothesis. A class of two-stage U -statistics (TU-statistics) is proposed to remedy these drawbacks. Both the asymptotic distributions under the null and the alternative of TU-statistics are shown to have simple forms. When the degeneracy is indeterminate, the Pitman asymptotic relative efficiency of a TU-statistic dominates that of the incomplete U -statistics. If the kernel is degenerate under the null hypothesis but non-degenerate under the alternative, a TU-statistic is proved to be more powerful than its corresponding U -statistic. Applications to testing independence of paired angles in ecology and marine biology are given. Finally, a simulation study shows that a TU-statistic is more powerful than its corresponding incomplete U -statistic in almost all cases under two settings.     

Empirical likelihood tests for two‐sample problems via nonparametric density estimation

The authors study the problem of testing whether two populations have the same law by comparing kernel estimators of the two density functions. The proposed test statistic is based on a local empirical likelihood approach. They obtain the asymptotic distribution of the test statistic and propose a bootstrap approximation to calibrate the test. A simulation study is carried out in which the proposed method is compared with two competitors, and a procedure to select the bandwidth parameter is studied. The proposed test can be extended to more than two samples and to multivariate distributions.     

‘Wallbanking’, innovativeness and computer attitudes: 25–40-year-old ATM-users on the spot

Attitudes towards ‘wallbanking’ (making use of banking services through an Automated Teller Machine (ATM)) and self-reported frequency of wallbanking have been related to attitudes towards innovations and towards computers. The investigation also included the perception of advantages as well as disadvantages of wallbanking, factors that determine one's choice of a bank, man-machine problems related to the use of an ATM, and demographic factors. Using a sample of 201 respondents in the age range of 25 to 40 years, structural equation modeling revealed that wallbanking attitudes have a major influence on the frequency of using ATMs. The innovativeness attitude ‘New is wasteful’ also showed a clear negative link with the frequency of wallbanking. On the other hand, the relationship between computer attitudes and the frequency of using ATMs had to be rejected. Income and education proved to have an indirect link with the frequency of wallbanking, which refines other research findings. These results may reflect specific financial management characteristics of the age group under investigation.