两种情形下威布尔分布置信下限的确定

采用样本空间排序法,讨论了在Ⅰ型区间删失数据情形下和定时截尾情形下的数据服从威布尔分布时的可靠度置信下限问题,其中威布尔分布的形状参数是在某有限区间内.对给定的置信水平和任意大小的样本,给出了威布尔分布下可靠度置信下限的确定方法.     

中西方古典园林的差异、原因及本质探析

园林是人类理想中的天堂,不同的自然环境和自然观孕育了不同的园林理想和现实的园林形式.中国古典园林追求天人合一,强调自然与精神的和谐,西方古典园林则追求秩序与几何美,强调对自然的控制与征服.本文阐述了中西方古典园林的表征差异,分析了造成差异的主要原因,指出其本质原因在于自然环境的不同.     

The psychophysical lifting capacities of Chinese subjects

The psychophysical lifting capacity (MAWL) of twelve subjects was determined in this study. The subjects were all young Chinese males who performed lifting tasks in three lifting ranges (floor to knuckle, floor to shoulder, and knuckle to shoulder) and four lifting frequencies (one-time maximum, 1 lift/min, 4 lifts/min, and 6 lifts/min). The oxygen uptake (1/min) and heart rate (beats/min) were recorded while subjects were lifting. Upon completion of each lifting task, the subjects were required to rate their perceived exertion levels. The statistical analyses results indicated the following. Chinese subjects have smaller body size and MAWLs compared with past studies using the US population. The MAWLs decreased with an increase in lifting frequencies. The decrements of MAWL due to lifting frequencies were in agreement with the results of past studies. However, there were larger decreases due to lifting ranges. The MAWLs of the floor to knuckle height lift were the largest, followed by the MAWLs of the floor to shoulder height lift, and the MAWLs of the knuckle to shoulder height lift. The measured physiological responses were considered similar to those obtained in past studies. Subjects' perceived stress levels increased with the lifting frequency and the upper extremities received the most stress for the total range of lifting tasks. The comparisons of the Chinese MAWLs with the NIOSH lifting guidelines for limits (AL and MPL) indicated that the vertical discounting factor in the guidelines should be modified before the NIOSH limits can be applied to non-Western populations.     

传统吉祥图案在古典建筑装饰中的应用

古典建筑中的吉祥图案是建筑的重要组成部分,凝结了中国传统文化的精髓．本文简单介绍了传统吉洋图案的产生背景及寓意,并从屋顶、门窗、铺地设计等方面对吉祥图案在古典建筑装饰中的应用进行了分析．     

中西方古典园林建筑的差异原因及本质浅析

中西方古典园林建筑存在很大的差异。论文从中西方古典园林建筑的类型、位置、功能、在园林中的数量和密度、建造者、建筑材料、结构、形态、体量、色彩、质感以及园林建筑的来源及地位等方面对比、分析了各自的特点。从审美意识、思维方式、生存环境三个方面浅析了产生这些差异的原因,指出中西方园林建筑差异的本质是自然环境的不同。     

1981—2011年少数民族古籍整理出版理论研究综述

文章从少数民族古籍整理出版的意义、方法、翻译、人才建设以及数字化研究5个方面对近30年我国少数民族古籍整理出版理论研究成果进行了系统的梳理和总结,以期对这一时期少数民族古籍整理出版理论研究有一个宏观的了解和把握。     

基于时序CPN的交叉路口车辆控制模型

对比经典Petri网模型，提出了基于时序CPN的交叉路口车辆控制模型，从时间和空间上对车辆的流通进行描述。使用CPN Tools建立时序CPN模型并进行仿真，模拟了交叉路口的车辆交通过程，实验结果证明该模型很好的反映了车辆流通时的时间和位置信息等动态特征。     

Single neurons in the medial prefrontal cortex of the rat exhibit tonic and phasic coding during trace fear conditioning.

Trace fear conditioning is a learning task that requires the association of an auditory conditioned stimulus (CS) and a shock unconditioned stimulus (US) that are separated by a 20-s trace interval. Single neuron activity was recorded from the prelimbic and infralimbic areas of the medial prefrontal cortex in rats during trace fear conditioning or nonassociative unpaired training. Prelimbic neurons showed learning-related increases in activity to the CS and US, whereas infralimbic neurons showed learning-related decreases in activity to these stimuli. A subset of prelimbic neurons exhibited sustained increases in activity during the trace interval. These sustained prelimbic responses may provide a bridging code that allows for overlapping representations of CS and US information within the trace fear conditioning circuit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Move limits definition in structural optimization with sequential linear programming. Part II: Numerical examples

A variety of numerical methods have been proposed in literature in purpose to deal with the complexity and non-linearity of structural optimization problems. In practical design, sequential linear programming (SLP) is very popular because of its inherent simplicity and because linear solvers (e.g. Simplex) are easily available. However, SLP performance is sensitive to the definition of proper move limits for the design variables which task itself often involves considerable heuristics. This research presents a new SLP algorithm (LESLP) that implements an advanced technique for defining the move limits. The linearization error sequential linear programming (LESLP) algorithm is formulated so to overcome the traditional limitations of the SLP method. In a companion paper [Comput. Struct. 81 (2003) 197] the basics of the LESLP formulation along with a guide to programming are provided.The new algorithm is successfully tested in weight minimisation problems of truss structures with up to hundreds of design variables and thousands of constraints: sizing and configuration problems are considered. Optimization problems of non-truss structures are also presented. The numerical efficiency, advantages and drawbacks of LESLP are discussed and compared to those of other SLP algorithms recently published or implemented in commercial software packages.     

提高无刷直流电动机最大运行电流的一种方法

针对无刷直流电动机控制系统限流功能在高转矩和堵转两种运行工况下的矛盾，文章提出了一种简便易行且性能价格优异的改进方法，并进行了理论上的论证和实际产品验证。