英语语法教学中显性意义的基础性地位

近年来,在英语语法教学中,语法形式在不同语境中的隐性意义被高度关注,这弥补了以往语法教学只注重形式和其显性意义的不足。但隐性意义的推理和理解离不开显性意义的掌握,因为隐性意义的获得,依赖于显性意义和语境的结合。简要介绍语法形式显性意义和隐性意义的概念,并通过隐性意义推理过程中基本因素的分析,揭示显性意义的基础性地位,强...     

To use or not to use propensity score matching?

Propensity score matching (PSM) has been widely used to reduce confounding biases in observational studies. Its properties for statistical inference have also been investigated and well documented. However, some recent publications showed concern of using PSM, especially on increasing postmatching covariate imbalance, leading to discussion on whether PSM should be used or not. We review empirical and theoretical evidence for and against its use in practice and revisit the property of equal percent bias reduction and adapt it to more practical situations, showing that PSM has some additional desirable properties. With a small simulation, we explore the impact of caliper width on biases due to mismatching in matched samples and due to the difference between matched and target populations and show some issue of PSM may be due to inadequate caliper selection. In summary, we argue that the right question should be when and how to use PSM rather than to use or not to use it and give suggestions accordingly.     

网络信息的分类

网络信息浩如烟海,分类五花八门,依据传统文献信息分类法的科学性和系统性对其进行分类非常重要。本文就网络信息分类特点及其信息分类中存在的问题进行探讨,对建设统一的网络信息分类体系提出了自己的看法。     

基于Bayes推理的灾害演化GERT网络模型研究

灾害、衍生和次生灾害及其相互耦合使得灾情恶化,作为灾害对抗力量的抢险、避险、控制的救险等措施使得灾害向灾情减轻的方向转化,本文对灾害的这一动态演化过程进行描述,建立一种综合考虑灾害的自然演化与抢险救灾行动的基于Bayes推理的灾害演化GERT(Graph Evaluation and Review Technique)网络模型;把GERT网络方法和贝叶斯推理工具相结合,根据获得的新信息,对GERT网络中活动参数进行动态修正,对灾害的演化路径,各种主要状态的演化概率和时间进行动态预测、预警与评价;对衍生与次生灾害、抢险救灾行动等外界行为对系统演化的影响进行定性与定量分析,并给出定量评价结论。本文提供了灾害演化定性与定量结合的分析框架与工具,揭示灾害演化机理,为灾害发展态势的预测、预警与评价提供了一种新的研究方法和研究思路。     

On the inference rules in legal logic

推论规则是逻辑学研究的核心内容。法律逻辑是一门应用逻辑,但它并不是形式逻辑的推论规则在法律领域中的简单运用,而是形式逻辑的推论规则加上法律领域中的特殊推论规则的结果。因此,法律逻辑中的推论规则与形式逻辑中的推论规则相比,既有共性的一面,又有个性的一面。其共性表现为形式逻辑的基本推论规则是构成法律逻辑中的推论规则必不可少的组成部分,其个性表现为法律逻辑中有着与形式逻辑中的推论规则所不具有的特殊推论规则——证明责任规则。     

基于Lucene的站内搜索引擎研究

网站提供的站内查询系统存在着系统不能自动采集网络信息,以及模糊查询结果准确率低等缺点.因此,应用搜索引擎的工作原理,设计了一种基于Lucene的站内搜索引擎系统,实现了站内信息的增量采集、自动分词和建立倒排索引功能.该系统的建立,提高了用户站内搜索的准确率和查全率,使站内信息资源能得到充分利用.     

基于DSP的Fuzzy-PID发动机怠速控制应用

为了有效改善发动机怠速工况下经济性与排放性,考虑怠速工况的非线性、时变性和不确定性等因素,采用怠速Fuzzy-PID控制算法,利用Simulink和Stateflow工具对Fuzzy-PID发动机怠速控制系统进行建模仿真.结果表明该Fuzzy-PID控制器,有良好的实时性、抗干扰性和鲁棒性.同时为解决控制系统的实时性能,在硬件设计上采用功能强大的可编程定点DSP控制芯片TMS320F2812,来实现信号处理与控制功能.     

空间数据分析的发展

空间统计学是研究空间问题的一门学科,它是应用数学快速发展的一个分支。尽管传统的数据分析中有许多很好的方法,但却不能完全地套用于空间数据的分析。空间模型的估计不仅与各种回归形式的假设有关,而且还与空间相关、空间异质的特性有关。从空间模型及推断、适应性估计、非参数回归、空间不相关性检验几个方面研究了空间数据分析方法的发展以及未来的趋势。     

Conditionally Reducible Natural Exponential Families and Enriched Conjugate Priors

Consider a standard conjugate family of prior distributions for a vector-parameter indexing an exponential family. Two distinct model parameterizations may well lead to standard conjugate families which are not consistent, i.e. one family cannot be derived from the other by the usual change-of-variable technique. This raises the problem of finding suitable parameterizations that may lead to enriched conjugate families which are more flexible than the traditional ones. The previous remark motivates the definition of a new property for an exponential family, named conditional reducibility. Features of conditionally-reducible natural exponential families are investigated thoroughly. In particular, we relate this new property to the notion of cut, and show that conditionally-reducible families admit a reparameterization in terms of a vector having likelihood-independent components. A general methodology to obtain enriched conjugate distributions for conditionally-reducible families is described in detail, generalizing previous works and more recent contributions in the area. The theory is illustrated with reference to natural exponential families having simple quadratic variance function.     

沥青洒布管道清洗问题的探讨

本文指出了洒布管道清洗操作中存在的问题并提出了新的清洗方案,分析 计算了车载式沥青洒布管道内的沥青流动阻力,并从理论和实践上证明了利用发 动机排气对沥青洒布管道进行清洗的可行性.