词汇能力与语境知识-补缺假设的启示

阐述了二语语境知识在二语学习者词汇发展过程中的重要意义。通过讨论词汇能力的不同定义和词汇能力与词汇知识的区别以及二语词汇发展的三个阶段揭示了词汇能力的本质及其发展规律。王初明提出的补缺假设强调了语境在二语习得中的重要作用,这为减少二语词汇发展阶段中的石化的可能性以及提高二语学习者的词汇能力给予了一定启示,也促使了二语词汇教与学中对词汇习得和语境结合方法的探讨。     

银行间市场回购利率变化的利率模型解释

在中国银行间市场的回购市场上,回购利率具有明显的期间风险溢酬,风险溢酬随时间变化,并与回购利率期限结构水平明显相关.文章试图构造单因子、两因子本性仿射模型来解释回购利率的变化及风险溢酬,发现两因子本性仿射模型与单因子本性仿射模型相比,对回购利率期限结构变化的描述没有明显改进.回购利率期限结构扣除单因子模型给出的利率风险溢酬后,服从纯预期假设,单因子本性仿射模型可以解释银行间市场回购利率风险溢酬的变化.     

中国股票市场长期记忆特征的实证研究

股票市场收益的长期记忆特征对于系统非线性结构的确定以及市场有效性的研究具有重要的意义.针对上海和深圳的周和日收益序列,采用非线性估计方法提高R/S系列分析估计H参数的精确度.并用ARFIMA模型对沪深股市的收益率的长期记忆性进行了检验,根据分段检验的结果,得出一些中国证券市场有效性的结论.     

光谱法研究钙黄绿素与鲱鱼精DNA的相互作用

本实验在接近生理条件下,以吖啶橙(AO)作为光谱探针,采用UV-Vis光谱、荧光光谱、热变性等方法研究了钙黄绿素(CA)与鲱鱼精DNA的作用机制.确定了钙黄绿素(CA)与鲱鱼精DNA之间主要以嵌插方式作用,钙黄绿素(CA)能对鲱鱼精DNA的生物功能产生一定影响.     

Coral cover as a proxy of disturbance： A case study of the biodiversity of the hermatypic corals in Yongxing Island, Xisha Islands in the South China Sea

The Yongxing Island is the biggest island of Xisha Islands in the middle part of the South China Sea. It occupies 1.8 square kilometers of land area and has permanent residence on it. There are only a few papers on the coral community of the Xisha Islands, reporting the species composition, structure and zonations of the hermatypic coral community in 1970s. The present study describes the hermatypic coral community based on the quadrat survey after almost 30 years in Yongxing Island in August 2002. It was the first time to present the percent cover data of live corals of Yongxing Island via a systematic scheme of quantitative quadrat sampling. The average total percent cover of the live coral is 68.4%. We found the total percent cover （TPC） could be an idea proxy of the overall disturbance regime impinging on the coral community. TPC can be used as an integrated measure of disturbance to coral reef. Using this surrogate, the best fit relation between TPC of the live corals and species richness, species diversity, or the species evenness is the unimodal second-order polymorphic parabola equation. This result is expected by the intermediate disturbance hypothesis （IDH）. From the fitted parabola equations, we calculated the best TPCs corresponding to the maximal species richness, the highest species diversity, or the most evenness respectively. They are surprisingly stabilized between 55% and 58%. Coral cover is the basic parameter widely available for most observation, research or monitoring programs. The good qualitative characteristics of percent cover provide powerful tool for the experimental, theoretical and modeling studies of coral reef in response to the disturbance.     

基于等价空间算法的飞控系统故障诊断

采用全局滤波法对操纵舵面损伤故障进行检测,等价空间法提取故障信息,以二元假设检验为判决准则,采用传感器数据融合方法进行预警、校验和隔离,作出故障诊断。仿真结果表明,该方法能大大提高故障诊断的速度和精度。     

中医证候的多元统计分析及方法研究

从"高脂血症及动脉粥样硬化痰瘀证候的蛋白质组学研究"的数据出发,研究影响中医证候的各主要因素。对11种可能的标志蛋白质(群)数据进行分析,以统计聚类为主导思想,给出变量聚类和样本数据聚类综合应用的方法,并结合医学角度对变量聚类结果的分析,指导组内和组间两种样本聚类讨论;同时,通过假设检验,从统计理论上对所得分类予以支持。最后得到标志蛋白质群{结合珠蛋白前体,α-胰蛋白酶抑制剂轻链,脂肪细胞脂质结合蛋白异构体3,补体C4}或{纤维蛋白原γ链,α-胰蛋白酶抑制剂轻链,未确定名称的蛋白(ID1485)}。考虑可能是区分高脂血症及动脉粥样硬化痰证和瘀证的标志蛋白质群,从而给出蛋白质水平上对痰证和瘀证判决方法的建议。     

基于多重假设检验市长公开电话文本的自动分类

提出一种基于多重假设检验的特征加权朴素贝叶斯分类算法, 该算法通过特征选择方法得到多个特征词集合, 再按多重假设检验错误率为每个特征词集合配以不同的权重系数并参与到分类器的构建中. 该方法已经应用到市长公开电话的文本分类中, 通过构建的3个特征加权朴素贝叶斯分类器实现了投诉文本的计算机自动分类, 且相对传统方法提高了分类器的效率和精度.     

论比较研究在运动训练中的应用

比较研究是现代科技发展中一种重要的认识方法。本文首先把训练中的统计比较方法概括为两种类型。然后对典型例证进行分析,将讨论引向深入,并提出了新的方法。     

Investigating the relationship between gold and silver prices

This paper analyses the long-run relationship between gold and silver prices. The three main questions addressed are: the influence of a large bubble from 1979:9 to 1980:3 on the cointegration relationship, the extent to which by including error-correction terms in a non-linear way we can beat the random walk model out-of-sample, and the existence of a strong simultaneous relationship between the rates of return of gold and silver. Different efficient single-equation estimation techniques are required for each of the three questions and this is explained within a simple bivariate cointegrating system. With monthly data from 1971 to 1990, it is found that cointegration could have occurred during some periods and especially during the bubble and post-bubble periods. However, dummy variables for the intercept of the long-run relationships are needed during the full sample. For the price of gold the non-linear models perform better than the random walk in-sample and out-of-sample. In-sample non-linear models for the price of silver perform better than the random walk but this predictive capacity is lost out-of-sample, mainly due to the structural change that occurs (reduction) in the variance of the out-of-sample models. The in-sample and out-of-sample predictive capacity of the non-linear models is reduced when the variables are in logs. Clear and strong evidence is found for a simultaneous relationship between the rates of return of gold and silver. In the three type of relationships that we have analysed between the prices of gold and silver, the dependence is less out-of-sample, possibly meaning that the two markets are becoming separated. © 1998 John Wiley & Sons, Ltd.