我国网络远程教育及其质量保证问题述评

网络远程教育是主要通过多媒体网络、以学习者为中心的非面授教育方式。它以其覆盖面广、交互性好、不受时空限制、共享教育资源、扩大教育规模等优势得到了迅速发展。然而，在规模迅速扩张的过程中，也出现了数量与质量不和谐的现象。为此，应围绕网络远程教育机构来构建质量保证体系，包括内部质量保证体系和外部质量保证体系。     

A new hybrid estimation method for the generalized pareto distribution

ABSTRACT

The generalized Pareto distribution (GPD) is important in the analysis of extreme values, especially in modeling exceedances over thresholds. Most of the existing methods for estimating the scale and shape parameters of the GPD suffer from theoretical and/or computational problems. A new hybrid estimation method is proposed in this article, which minimizes a goodness-of-fit measure and incorporates some useful likelihood information. Compared with the maximum likelihood method and other leading methods, our new hybrid estimation method retains high efficiency, reduces the estimation bias, and is computation friendly.     

Three estimators of the Mahalanobis distance in high-dimensional data

This paper treats the problem of estimating the Mahalanobis distance for the purpose of detecting outliers in high-dimensional data. Three ridge-type estimators are proposed and risk functions for deciding an appropriate value of the ridge coefficient are developed. It is argued that one of the ridge estimator has particularly tractable properties, which is demonstrated through outlier analysis of real and simulated data.     

从叙述话语再看《蝇王》中的希望之光——细读威廉·戈尔丁小说《蝇王》

本文从剖析《蝇王》所运用的叙述话语入手，着重探讨其为一般评论所忽略的积极的警世主题，揭示该小说作者在“邪恶必胜”的表象下所潜藏着的对人性及人类未来的乐观立场。     

Let's meet up! The role of relational goods in promoting cooperation

The present paper draws on data collected through a Traveler's Dilemma experiment where the possibility of consuming relational goods is introduced by allowing (or forcing) agents to meet after the experiment. It enriches the literature on social distance by comparing the effect of its reduction when it is a voluntary subject's choice and when it is compulsory.We show that the existing interpretations of the effect of social distance reduction cannot explain the differences in agents’ behavior across our experimental treatments. This allows us to give to the theory of social distance an original interpretation based on the concept of relational goods where the possibility to consume relational goods promotes non-selfish behavior.     

Measures of Dependence and Tests of Independence

Measures of dependence and resulting tests of independence are surveyed. Measures arising both from linear and nonlinear modeling are examined. Tests based on chaos theory are briefly discussed. The main emphasis, however, is on some recently developed nonparametric tests using estimated distribution and density functions. Most of the paper is phrased in terms of serial dependence for a univariate stationary time series, but it is indicated how more general situations can be analysed. The bootstrap is an essential tool for determining the critical value of the new tests.     

试述西方哲学发展的内在逻辑

本文立足于传统西方哲学和现代西方哲学,并在理解＂能否思想＂＂有无意义＂的基础上,试图进一步阐述西方哲学从古代本体论经由近代认识论到现代价值论或曰意义论的内在发展逻辑——＂能否思想＂＂有无意义＂。     

The genetic heterogeneity of deer mouse populations ( Peromyscus maniculatus ) in an insular landscape

A survey of the genetic variability in deer mouse populations was performed using specimens collected from six different islands on a lake covering approximately 50 km². Random amplified polymorphic DNA (RAPD) was used to measure the extent of the genetic differences in this insular system. An analysis of molecular variance (AMOVA) revealed that populations are clearly separated at this microgeographic scale (F _st = 0.13863; P < 0.001). The homogeneity of molecular variance test (HOMOVA) indicated that within-population levels vary greatly (B _p = 0.76831; P < 0.001). The within-population molecular variance was found to be mainly correlated with the accessibility of the islands, computed as the inverse of the geographic distance separating an island from the lakeshore (r = 0.916; P < 0.003). Received: March 5, 1999 / Accepted: July 16, 1999     

关于圆的一个定值问题的推广

设P是圆上任意一点 ,P到与圆外离 (内离、相交 )正n边形A1A2 …An 各边的距离分别为d1,d2 ,… ,dn,本文给出当m为自然数时 ,∑ni =1dmi 为定值的条件以及 ∑ni =1dmi 为定值时的定值表达式。