少年运动员焦虑自评量表测查结果的统计分析

应用焦虑自评量表(SAS)调查了558名10～16岁的少年运动员,结果表明少年运动员SAS均分为40.65±9.47,以SAS标准分50为划界分,16%的少年运动员有不同程度的焦虑症状。     

英语口试初探

英语高考口试作为英语专业考生和与英语有关专业考生录取的必考科目已越来越受到重视.英语四级口试逐步在全国范围内推广.本文就英语口试内容、训练方法及考试对策问题作简略介绍与探讨.     

On-line estimation of concentration parameters in fermentation processes

INTRODUCTION Saccharomycete, closely linked with human life, is the only microbe that has been utilized to the extent of over a million tons in the world, and is one of the modelled biological bacteria mostly used in modern genetic engineering. Since there are no effective online instruments for measuring the production or resultant concentration, which is a very important quality index in fermentation process, soft sensors (Martin, 1997; Tham et al., 1991; Assis and Filho, 2000; Salgad…     

基于EM算法的汉语自动分词方法

汉语自动分词是中文信息处理中的基础课题。本文首先对汉语分词的基本概念与应用 ,以及汉语分词的基本方法进行了概述。接着引出一种根据词的出现概率、基于极大似然原则构建的汉语自动分词的零阶马尔可夫模型 ,并重点剖析了EM(Expectation Maximization)算法 ,对实验结果进行了分析。最后对算法进行了总结与讨论。     

小样本容量的IRT参数估计系统的设计与实现

目前IRT参数估计程序大多数都要求大样本容量,而基于小样本容量的IRT参数估计系统非常少,但在测验实践中小样本容量的情况经常出现.本文根据测验的实际和对IRT参数估计方法的比较研究设计开发了一个基于小样本容量的IRT参数估计系统.该系统界面友好,操作简单,估计精度高,有一定的应用推广价值.     

Introduction to Sample Size Choice for Confidence Intervals Based on t Statistics

Sample size can be chosen to achieve a specified width in a confidence interval. The probability of obtaining a narrow width given that the confidence interval includes the population parameter is defined as the power of the confidence interval, a concept unfamiliar to many practitioners. This article shows how to utilize the Statistical Analysis System (SAS) proc power procedure to determine an appropriate sample size and achieve sufficient power for a specified confidence interval. Two examples in sport and exercise science are used to illustrate sample size determination for confidence intervals in the dependent and independent t tests. The relevant SAS code and output are provided with detailed annotations. As the use of confidence intervals becomes a more integral part of studies in sport and exercise science, the reporting and analysis of their power should be considered much like that of hypothesis tests.     

基于高斯混合模型的图像检索算法研究

通过研究聚类算法在图像处理上的应用,提出了一种基于高斯混合模型聚类的图像检索方法。该检索方法首先提取每幅图像的特征,并以特征值为数据集建立高斯混合模型,得到所有图像的高斯混合模型。再以所有图像的混合模型参数集作为数据集,用基于高斯混合模型的聚类算法进行聚类。最后输出检索例图所在的类,即得到检索结果。     

基于教育心理学研究新进展的教与学——针对教学环境的研究的启示

教学环境对于学生的学业成就和智力发展有着至关重要的影响。教学环境可分为教育环境与学习环境。本文将从教育心理学针对教学环境的新进展入手,探讨教育环境、教学环境对学生学业成就、学业自我概念的影响,以针对课堂情感氛围和Marsh的I＼E模型与大鱼小池效应的组合模型为重点,探讨其对于教与学的启示。     

一种改进EM算法的联合信道估计与数据检测

最近的一些研究表明,在接收机利用可用的信道估计误差的统计时,可以显著提高检测性能.对此,提出了一种基于改进期望最大化（EM）算法的数据辅助信道估计,它通过在每次迭代中提供估计误差的统计信息,减少在各自的接收器信道估计误差的影响.仿真结果表明,与传统的EM及VBEM算法相比,在不需增加接收机复杂程度的情况下,改进的EM算法在估计精度上优于其对应的传统估计方法,有效降低了信道估计误差,其误码性能接近理想信道时的性能.     

A simple channel estimator for space-time coded OFDM systems in rapid fading channels

A simple channel estimator for space-time coded orthogonal frequency division multiplexing (OFDM) systems in rapid fading channels is proposed. The channels at the training bauds are estimated using the EM (expectation-maximization) algorithm, while the channels at the data bauds are estimated based on the method for modelling the time-varying channel as the linear combination of several time-invariant "Doppler channels". Computer simulations showed that this estimator outperforms the decision-directed tracking in rapid fading channels and that the performance of this method can be improved by iteration.