The residual effect of a growth-decay mechanism and the distributions of covariance structures

The product of two independent or dependent scalar normal variables, sums of products, sample covariances, and general bilinear forms are considered. Their distributions are shown to belong to a class called generalized Laplacian. A growth-decay mechanism is also shown to produce such a generalized Laplacian. Sets of necessary and sufficient conditions are derived for bilinear forms to belong to this class. As a generalization, the distributions of rectangular matrices associated with multivariate normal random vectors are also discussed.     

试论「～と会う」和「～に会う」的用法和区别

在学习和运用日语过程中 ,格助词是比较难以准确掌握和运用的 ,人们往往习惯从格助词本身去分析其语法功能。从动词词义决定其格助词在句子中的构式的角度看 ,格助词 [と ]表示行为动作的共同主体 ,格助词[に ]表示行为动作的承受者。进一步说 [～と会う ]所表达的这一 [会う ]的行为动作是双方共同的行为动作。[～に会う ]所表达的这一 [会う ]的行为动作是单方面的行为动作 ,另一方是这一行为动作的承受者     

中日菜名音节构造模式差异之比较研究

中式菜肴的命名在音节方面具有一些特征,并有一定的规律可循,日式菜肴的命名同样如此。中日菜名在音节构造模式上有各自的特点和规律。     

“民工荒”：产业结构升级的契机——透视“民工荒”现象

在我国农村大量剩余劳动力需要转移、城市就业形势严峻的情况下,我国东南沿海地区出现"民工荒"现象值得关注。对此问题,众多学者曾从不同角度进行了分析,但大多是就现象而论。这里则从产业结构升级与相应的人力资源素质关系分析出发,认为"民工荒"是民工素质与产业结构升级不适应的结果,其根源在于民工双重身份所衍生的诸多问题,对此背后之原因进行了深入分析,同时就"民工荒"现象带来的警示进行了揭释。     

读者·作品·召唤结构--关于多维文学接受的一种构想

艾布拉姆斯的文学批评四要素中,“读者”是最后一个进入研究领域的。注重读者创造性的文学接受过程事实上涉及到接受主体的一切方面,并通过作品的阅读评价曲折地反映出来。受伊瑟尔认为作品是一种“召唤结构”式的存在启发,我们提出读者也是一个具有特定含义的“召唤结构”,并主要通过心理学和哲学解释学的方法为文学接受过程的复杂性和多维性做出一个尽可能清晰的理论描述,使文学解释获得一个相对稳定和可靠的立足点,进而对读者的接受心态起到一个预先调节的作用。     

图式理论、学习策略与大学英语口语教学

本研究采用定量分析的方法,对84名天水师范学院非英语专业的学生的口语水平进行测试。根据图式理论,口语任务分为有关键词及句型提示类和无提示类,并对被试的学习策略使用情况做了调查,结果发现,口语任务有提示与无提示对学生的口语成绩有显著影响,这说明图式理论完全适用于大学英语口语教学。     

从知识分类的角度构建新的课堂教学结构

自凯洛夫的五步课堂教学结构产生以来,关于教学结构的探讨一直没有间断。但是,传统的教学结构常常囿于学时与教学内容之间的一一对应关系,而且没有明确的知识分类的观念,忽略了学习和教学过程的多样性。针对此种现象,应根据现代认知心理学中知识分类的思想,构建新的课堂教学结构。     

On the logic of common belief and common knowledge

The paper surveys the currently available axiomatizations of common belief (CB) and common knowledge (CK) by means of modal propositional logics. (Throughout, knowledge — whether individual or common — is defined as true belief.) Section 1 introduces the formal method of axiomatization followed by epistemic logicians, especially the syntax-semantics distinction, and the notion of a soundness and completeness theorem. Section 2 explains the syntactical concepts, while briefly discussing their motivations. Two standard semantic constructions, Kripke structures and neighbourhood structures, are introduced in Sections 3 and 4, respectively. It is recalled that Aumann's partitional model of CK is a particular case of a definition in terms of Kripke structures. The paper also restates the well-known fact that Kripke structures can be regarded as particular cases of neighbourhood structures. Section 3 reviews the soundness and completeness theorems proved w.r.t. the former structures by Fagin, Halpern, Moses and Vardi, as well as related results by Lismont. Section 4 reviews the corresponding theorems derived w.r.t. the latter structures by Lismont and Mongin. A general conclusion of the paper is that the axiomatization of CB does not require as strong systems of individual belief as was originally thought — onlymonotonicity has thusfar proved indispensable. Section 5 explains another consequence of general relevance: despite the infinitary nature of CB, the axiom systems of this paper admit of effective decision procedures, i.e., they aredecidable in the logician's sense.     

Sampling from spatial databases

This paper deals with techniques for obtaining random point samples from spatial databases. We seek random points from a continuous domain (usually ²) which satisfy a spatial predicate that is represented in the database as a collection of polygons. Several applications of spatial sampling (e.g. environmental monitoring, agronomy, forestry, etc) are described. Sampling problems are characterized in terms of two key parameters: coverage (selectivity), and expected stabbing number (overlap). We discuss two fundamental approaches to sampling with spatial predicates, depending on whether we sample first or evaluate the predicate first. The approaches are described in the context of both quadtrees and R-trees, detailing the sample first, acceptance/rejection tree, and partial area tree algorithms. A sequential algorithm, the one-pass spatial reservoir algorithm is also described. The relative performance of the various sampling algorithms is compared and choice of preferred algorithms is suggested. We conclude with a short discussion of possible extensions.     

电信产业投入产出模型的应用研究

本文以全国价值型投入产出表中独立出来的电信产业投入产出表为基础,探讨投入产出模型方法在我国电信产业中的应用,主要介绍了电信产业投入产出模型的开发背景、模块层次结构及其应用分析。