自组织理论对技术发展极限问题的启示

技术的发展从内史和外史的角度来说都会遇到发展极限的问题,自组织理论对技术发展极限问题的认识有重要的启示:技术系统的涨落对技术发展的极限实现维持与突破;技术系统的开放性对技术发展的极限实现促进与制约;技术系统的序参量对技术发展的极限实现役使和规导。正确认识技术发展的极限问题,对于促进技术的完善与革新,对于更好地规范技术的社会价值取向有重要的意义。     

Ultrastructural elliptical models

Dolby's (1976) ultrastructural model with no replications is investigated within the class of the elliptical distributions. General asymptotic results are given for the sample covariance matrix S in the presence of incidental parameters. These results are used to study the asymptotic behaviour of some estimators of the slope parameter, unifying and extending existing results in the literature. In particular, under some regularity conditions they are shown to be consistent and asymptotically normal. For the special case of the structural model, some asymptotic relative efficiencies are also reported which show that generalized least squares and the method of moment estimators can be highly inefficient under nonnormality.     

A robust approach to longitudinal data analysis

The author introduces robust techniques for estimation, inference and variable selection in the analysis of longitudinal data. She first addresses the problem of the robust estimation of the regression and nuisance parameters, for which she derives the asymptotic distribution. She uses weighted estimating equations to build robust quasi‐likelihood functions. These functions are then used to construct a class of test statistics for variable selection. She derives the limiting distribution of these tests and shows its robustness properties in terms of stability of the asymptotic level and power under contamination. An application to a real data set allows her to illustrate the benefits of a robust analysis.     

中国古代农耕社会村落选址及其风水景观模式

风水是中国一门独特的文化和学说。它强调人与自然的和谐,其实质是追求理想的生存与发展环境。趋利避害是风水的普遍原则,中国传统乡土聚落立村选址、营宅造院都遵循着这一原则,审慎周密地考察、了解自然环境,利用和改造自然,创造良好的居住环境。因此传统村落中所体现的风水具有不可忽视的现实意义,研究其合理含义,能让风水思想在当代乡村转型期的村镇建设中发挥积极而有效的作用。     

北京市配送中心的选址研究

运用聚类分析对北京市配送中心的选址问题进行研究，北京市应将配送中心的地理位置确定为：海淀四道口、丰台玉泉营、莱广营、楼梓庄、青年路、久敬庄、海淀清河、丰台五里店，这样不但减少了配送中心的个数，而且在满足需求、提高服务水平及节约成本等方面也更具合理性。     

以产业集群推动农村剩余劳动力向中心镇转移——以广州市番禺区为例

产业集群的成长对城镇化和农村剩余劳动力转移具有重要意义。集群产生的规模效应带动了中心镇的发展,以产业集群为依托的中心镇又为农村剩余劳动力向城镇转移提供了出路。通过以广州市番禺区产业集群与农村剩余劳动力转移现状和走向的分析,可以看出其对农村劳动力转移的重要作用和目前存在的不足,提出产业集群与中心镇建设和农村人口转移相互促进的机理,在此基础上探讨了政府应发挥的作用。     

Graphical models for skew-normal variates

This paper explores the usefulness of the multivariate skew-normal distribution in the context of graphical models. A slight extension of the family recently discussed by Azzalini & Dalla Valle (1996 ) and Azzalini & Capitanio (1999 ) is described, the main motivation being the additional property of closure under conditioning. After considerations of the main probabilistic features, the focus of the paper is on the construction of conditional independence graphs for skew-normal variables. Necessary and sufficient conditions for conditional independence are stated, and the admissible structures of a graph under restriction on univariate marginal distribution are studied. Finally, parameter estimation is considered. It is shown how the factorization of the likelihood function according to a graph can be rearranged in order to obtain a parameter based factorization.     

Saddlepoint approximations for some models of circular data

In this article we provide saddlepoint approximations for some important models of circular data. The particularity of these saddlepoint approximations is that they do not require solving the saddlepoint equation iteratively, so their evaluation is immediate. We first give very accurate approximations to P-values, critical values and power functions for some optimal tests regarding the concentration parameter under wrapped symmetric α-stable and circular normal models. Then, we consider an approximation to the distribution of a projection of the two-dimensional Pearson random walk with exponential step sizes.     

基于定置管理的高速公路施工安全文化观研究

运用定置管理的科学原理和方法来进行高速公路施工现场的安全管理工作,可有效地使安全文明施工长期化,从而形成安全文化观,使公路工程建设项目优质高效安全文明地进行。     

基于振动分析的工程结构损伤识别技术综述

综述了基于振动分析的工程结构损伤识别方法,并对各种方法进行了评述。根据国内外文献,对基于振动分析的工程结构损伤识别技术的发展趋势进行了展望。