Point and confidence interval estimates for a global maximum via extreme value theory

The aim of this paper is to provide some practical aspects of point and interval estimates of the global maximum of a function using extreme value theory. Consider a real-valued function f:D→? defined on a bounded interval D such that f is either not known analytically or is known analytically but has rather a complicated analytic form. We assume that f possesses a global maximum attained, say, at u*∈D with maximal value x*=max _u  f(u)?f(u*). The problem of seeking the optimum of a function which is more or less unknown to the observer has resulted in the development of a large variety of search techniques. In this paper we use the extreme-value approach as appears in Dekkers et al. [A moment estimator for the index of an extreme-value distribution, Ann. Statist. 17 (1989), pp. 1833–1855] and de Haan [Estimation of the minimum of a function using order statistics, J. Amer. Statist. Assoc. 76 (1981), pp. 467–469]. We impose some Lipschitz conditions on the functions being investigated and through repeated simulation-based samplings, we provide various practical interpretations of the parameters involved as well as point and interval estimates for x*.     

基于搜索的空间方向关系推理

方向关系是空间关系的重要组成部分，用以确定空间对象间的一种顺序．讨论了方向关系的定性表示模型和基于方向关系组合运算表的方向关系定性推理，介绍了求解约束满足问题（CSP）的回跳搜索算法。并将回跳搜索算法用于方向关系组合运算表的定性推理．     

有效资产管制条件下电网企业资产更换决策方法分析

在有效资产管制的条件下,电网企业为规避管制风险.必然采用适当的方法对其资产更换需求做出预测与决策,并使其资产更换数量尽可能与管制机构的评估数量相一致.针对现行的资产更换方法未能充分反映电网有效资产管制以及可靠性与经济性的特点,本文综合考虑上述三个要素,在分析现有电网资产更换的理论与方法的基础上.提出和分析了电网企业资产更换决策的评分法.本文认为,这种方法能够更加准确地分析和诊断资产健康状况,特别适用于电网企业资产的短中期更换数量的预测与决策,对电网企业大修、技术改造项目的合理安排也具有一定的借鉴价值.     

寻求迷失的身份--解读《看不见的人》的思想主题

《看不见的人》是美国黑人作家拉尔夫·埃里森的代表作。作品主要从一个辛苦为生计奔波的美国黑人青年真实的社会感受出发,深刻地揭露了当时美国社会对黑人的压迫与藐视,使得处于各种不同地位的黑人们为融入白人社会而有意无意地丧失了身份。从美国黑人的身份迷失入手,对主人公丧失身份、寻找自我、实现自我的艰难心路历程进行分析,从而揭露了美国工业社会中,人为的精神歧视会导致黑人失去自我。     

Comparing search and estimation performances of designs based on a compound criterion

Since the introduction of the search design by Srivastava [Designs for searching non-negligible effects. In: Srivastava, editor. A survey of statistical design and linear models. Amsterdam: North-Holland, Elsevier; 1975. p. 507–519], construction of such designs has been considered by many researchers. The efficient performances of constructed search designs in terms of parameter estimation and search ability of parameters have also been investigated by several authors. They have proposed suitable optimality measures such as DD- and AD-optimality for estimation in the early stage of search design construction. Moreover, since 1990s, some criteria have been developed to evaluate search performance of a design. Although these criteria are useful none of them is able to evaluate both estimation and search efficiency of a design simultaneously. In this paper, we propose dual-task criteria to deal with searching and estimating performances of search designs. These compound criteria are weighted multiplication of estimation and search suitable criteria. They will be used for design comparison and the results will be presented.     

支持多关键字的P2P搜索研究

传统的P2P系统是基于单特征词搜索的，且不支持语义，存在一定的局限性。提出了可变长数组模型，解决了P2P系统中多特征词搜索的问题；标识符空间的分割，使相同领域的文档在邻近的节点聚集，提高了搜索速度；本体技术的应用，使P2P系统能够理解搜索请求，有利于查全率的提高。     

一种基于网格剖分的两点射线追踪方法

两点射线追踪是解决复杂地质结构下反射波射线正演的有效方法。在初至波层析射线追踪算法基础上，提出了一种两点射线追踪方法，利用层析网格对模型进行离散化，通过两阶段法射线追踪，分别对激发点和接收点按向前处理过程计算模型单元及节点的旅行时，两次时间相加作为最小旅行时，再在目的层界面邻域扫描最小旅行时子震源网格单元，用粒子群算法在该单元内扫描全局最小旅行时点，得到反射点位置与反射夹角，再利用向后处理过程运用旅行时线性插值算法，从反射点分别到激发点、接收点反向追踪射线路径，最后得到反射波两点射线路径。     

Using adaptive weighted least squares to reduce the lengths of confidence intervals

The author proposes an adaptive method which produces confidence intervals that are often narrower than those obtained by the traditional procedures. The proposed methods use both a weighted least squares approach to reduce the length of the confidence interval and a permutation technique to insure that its coverage probability is near the nominal level. The author reports simulations comparing the adaptive intervals to the traditional ones for the difference between two population means, for the slope in a simple linear regression, and for the slope in a multiple linear regression having two correlated exogenous variables. He is led to recommend adaptive intervals for sample sizes superior to 40 when the error distribution is not known to be Gaussian.     

Framing distance: local vs. non-local news in Hong Kong press

Geographical location as a “natural” attribute of news has always been a source of news manipulation. This research investigates how different community newspapers select, interpret, and package events originating in places of varying distances. Contextualized in Hong Kong, three media frames (authority, conflict, and attribution) are closely examined and theoretically connected to three types of newspapers (mass appeal, elite, and pro-establishment) across four locales (local, mainland China, Asian, and international). To test the hypotheses, a large-scale content analysis of 14 daily newspapers in Hong Kong was conducted. On the whole, findings supported the three hypotheses, showing that local news was systematically differentiated from non-local news in terms of the frequency of political authorities cited, presence of diversified opinions, and the likelihood of either individuals or institutions being blamed for social wrongs. Considerable variations were detected across different types of newspapers as well. Theoretical and social implications of the empirical findings are discussed.     

Web挖掘技术在搜索引擎中的应用与实现

介绍W eb挖掘技术及搜索引擎相关知识,并通过PageRank-pro W eb结构挖掘器和页面解析器中文分词两个实现来描述W eb挖掘技术在搜索引擎中的实现过程。