城市轨道交通走行轨上牵引电流值的分析

城市轨道交通一般采用直流牵引供电系统,走行轨上最大牵引电流及其持续时间会随着供电区间内牵引列车数的不同而异。本文运用数理统计的方法分析了城市轨道交通走行轨上各种牵引电流出现的概率及其持续的时间,并结合工程实例对走行轨上最大牵引电流的选择提出了建议。     

工程结构时变失效概率分析

用泊松脉冲随机过程模拟机车车辆荷载,考虑抗力随时间的变化,给出工程结构时变失效概率的计算公式。定性分析抗力衰减函数、荷载平均发生率和结构服役时间对失效概率的影响。结果表明,在其他因素确定的情况下,荷载发生频率的增大、结构服役时间的延长及抗力的衰减均会导致失效概率增加,其中抗力衰减引起结构失效概率的增加更明显。因此在服役过程中需对结构进行定期的检测维修,以确保其可靠性。     

解卫清气注射液对急性发热证的临床观察及实验研究

我们用自拟解卫清气注射液,临床观察61例急性发热患者,总有效率达95.08％。为了探明此药的退热机理,用10只家兔,随机分为实验组、对照组,每组5只,均用细菌内毒素(伤寒、副伤寒菌苗)造成发热模型,实验组注射此药,结果表明:P<0.01,有明显的退热意义;还通过小鼠腹腔巨噬细胞吞噬功能的实验观察,说明了此药能提高小鼠腹腔巨噬细胞的吞噬功能。     

"礼"的演变及其在中国古代法中地位和作用

我国是一个文化历史悠久、法律文化没有中断的国度,中华文明源源流长,悠久的历史灿烂的文化,积淀与其他文明不同的治国理念与传统。礼在中国古代法的形成过程中就表现出这一特色。它几经反复,几起几落,最终礼法融合合,以礼为本,形成独具特色的中华法律体系。其特征为“礼”是它的灵魂,“礼治”是它的标志。     

双正交小波滤波器族的构造

给出了一般双正交小波滤波器所对应多相矩阵分解形式及所对应的代数结构空间,完成了一个双正交小波滤波器设计程序.此程序不但可以给出任意双正交小波滤波器族参数表示,还可以用来刻划滤波器族代数结构.     

铁路车站咽喉区进路排列优化方法

合理排列接发列车和调车作业进路是保证铁路车站行车安全和提高行车效率的重要内容,在车站接发列车和调车作业自动化、车站行车作业过程模拟等方面也有着十分重要的意义。本文从有利于后续作业进路排列的目的出发,按序列化逐项作业排列进路的规则,分别提出了铁路车站咽喉区最大平行进路和最大概率进路的紧侧优化方法,该方法简明快捷,对现场计算和理论研究均有指导意义。     

门座起重机运行打滑的可靠性验算

在研究门座起重机驱动轮压及其许用值的概率分布特性和干涉模型的基础上．导出不打滑事件概率的解析解，提出门座起重机运行打滑的可靠性验算方法和验算准则．所阐述的运行打滑可靠性验算方法，是对较为严格且难以满足要求的按最小驱动轮压进行打滑验算方法的修正，更符合门座起重机的实际工作情况．     

基于模态参数的工程结构损伤识别方法

介绍了结构故障诊断的技术手段以及应用振动诊断进行结构损伤识别的研究现状。应用有限元程序进行模态分析和频响分析,得到在不同损伤度的条件下轮对局部模态频率和振幅幅值的变化趋势。提出基于频率移动和模态振型变化来判断结构损伤。     

A stated preference examination of time of travel choice for a recreational trip

A stated preference experiment was performed in Calgary in Canada to examine how people are influenced in the selection of a departure time for a hypothetical trip to see a movie. A total of 635 complete observations were obtained. In each observation the respondent was presented with a set of possible departure time scenarios and asked to indicate the order of preference for these scenarios. Each scenario was described by specifying the automobile travel time, the expected arrival time relative to the movie start time, the parking cost, the probability of being at least ten minutes late for the movie and the length of time the movie had been running. This forced the respondent to trade off between conditions regarding these attributes. Age, gender and frequency of movie attendance were also recorded. The observations thus obtained were used to estimate the parameter values for a range of alternative utility functions in logit models representing this choice behaviour. The results indicate that all of the attributes included have significant effects on departure time choice in the situation being considered. They also indicate that travellers are prepared to arrive roughly two minutes early for each minute of travel time saved; that the money value of driving time for trips to recreational activities is about half that for trips to work; that one additional percent in the probability of arriving late is equivalent to roughly 0.20 Canadian dollars or 1.93 minutes drive time; and that there is a preference for a non-zero expected early arrival time regardless of the associated probability of arriving late. Some of these results are novel and others are consistent with findings for work trips in work done by others, which is seen to add credence to the approach being used here.     

基于非完备贝叶斯网络的车型识别方法

针对BP神经网络等车型识别算法不能很好地适应我国车型复杂状况，分析了贝叶斯网络（IDS-BN）算法中完备数据集的问题，提出了基于非完备数据集的贝叶斯网络车型识别方法和车型识别系统结构模块，基于该模块拟定了车型特征变量．构建了车型识别网络模型，并给出了模型参数学习、车型分类器等算法，包括MDL评分和贪婪搜索的结构学习、EM参数学习、随机模拟采样推理等。实验表明，该方法识别率较高，鲁棒性好，满足我国车型识别的实际要求。