Positive embedded integration in Bayesian analysis

This paper describes how embedded sequences of positive interpolatory integration rules (PIIRs) obtained from Gauss-Hermite product rules can be applied in Bayesian analysis. These embedded sequences are very promising for two major reasons. First, they provide a rich class of spatially distributed rules which are particularly useful in high dimensions. Second, they provide a way of producing more efficient integration strategies by enabling approximations to be updated sequentially through the addition of new nodes at each step rather than through changing to a completely new set of nodes. Moreover, as points are added successive rules change naturally from spatially distributed non-product rules to product rules. This feature is particularly attractive when the rules are used for the evaluation of marginal posterior densities. We illustrate the use of embedded sequences of PIIRs in two examples. These illustrate how embedded sequences can be applied to improve the efficiency of the adaptive integration strategy currently in use.     

函数极限性质和存在性的证明

本文用归结原则将函数极限问题转化为数列极限问题去讨论,证明了函数极限性质与极限存在的判定定理,进而更清晰的刻画了函数极限与数列极根之间的关系。     

词义搭配在英语学习中的作用

随着社会的发展,语言也在不断地发展变化.词义的不同导致了实际表达的千差万别。本文从多义词,同义词, 单词记忆和语篇理解等几个方面论述了词义的搭配在英语学习中的重要作用。     

Polynomial approximations of multivariate smooth functions from quasi-random data

We improve a Monte Carlo algorithm which computes accurate approximations of smooth functions on multidimensional Tchebychef polynomials by using quasi-random sequences. We first show that the convergence of the previous algorithm is twice faster using these sequences. Then, we slightly modify this algorithm to make it work from a single set of random or quasi-random points. This especially leads to a Quasi-Monte Carlo method with an increased rate of convergence for numerical integration.     

科技英语语篇中的词汇同现

从国内外对衔接及词汇衔接的研究入手,立足于有关词汇同现关系研究的理论成果,在真实的土木工程英语语篇中分析词汇同现的手段和功能,从而揭示出科技英语语篇中词汇同现的特点:(1)在科技英语语篇中,同一序列关系常常出现在有关设计、施工程序类的篇章中;(2)非序列词汇套在关于机械、设备、仪器的使用或说明的科技英语语篇中体现得十分突出;(3)预期关系存在于专业性很强的篇章中,并且在这种关系中的词项虽然倾向于出现在同一语境中,但它们在语义上不一定有系统联系。     

Quasi-random resampling for the bootstrap

Quasi-random sequences are known to give efficient numerical integration rules in many Bayesian statistical problems where the posterior distribution can be transformed into periodic functions on then-dimensional hypercube. From this idea we develop a quasi-random approach to the generation of resamples used for Monte Carlo approximations to bootstrap estimates of bias, variance and distribution functions. We demonstrate a major difference between quasi-random bootstrap resamples, which are generated by deterministic algorithms and have no true randomness, and the usual pseudo-random bootstrap resamples generated by the classical bootstrap approach. Various quasi-random approaches are considered and are shown via a simulation study to result in approximants that are competitive in terms of efficiency when compared with other bootstrap Monte Carlo procedures such as balanced and antithetic resampling.     

二维非连续边界元分析积分计算的精确表达式

以二维弹性力学问题为研究对象，采用线性非连续元离散边界积分方程，给出了系数矩阵计算的精确表达式，对二维弹性力学问题进行了数值计算，对非连续边界元配位点对计算结果精度的影响进行了讨论，结果表明准奇异积分计算是配位点影响计算结构精度的主要因素。     

论义位和义素分析在语义理解中的作用

义位与义素分析法是语义理解中的基本理论和方法。这种方法通过提取词义中的某个特定义位,再把义位分解成多个义素加以分析,有助于更好地理解义位和义素在语义中的动态变化。通过义位义素分析法概括了义位组合的要求以及义位变异现象的发生,介绍了如何用义素分析的方法理解语义在语境中由静态到动态的变化,通过遗传义素的概念对词义进行历时的分析进而阐述了语义的深层结构。最后简要介绍了义位与义素的分析理论对计算机进行语义处理的指导意义。     

基于语料库的商务英语高频描述类词汇搭配研究——以英语单词financial为例

词语搭配已成为语言学研究的热点之一,从1957年搭配概念提出以来,研究者就对搭配的形式及类型进行了深入探讨。随着现代计算机技术文本运行效率的发展,商务英语词汇搭配研究进入了一个崭新的局面。基于语料库的方法,以英语高频单词financial为例,对商务英语描述类词汇的搭配进行定性和定量的分析及研究。     

基于COCA语料库的study和learn词语搭配研究

study和learn为常见的高频词。本文利用美国当代英语语料库COCA-CorpusofContemporaryAmericanEnglish对这两个词的用法,尤其是常用搭配进行了研究,从宏观和微观两方面总结了其典型搭配和总体使用情况,揭示了其使用规律,对语言研究和教学有一定的启发作用和指导意义。