HXD1C型机车司机操纵台造型优化设计

我国电力机车司机操纵台的设计在消化吸收国外的产品,但在造型设计上不够完美.文章对HXD1C型电力机车司机操纵台外观造型不够完美的地方进行了分析,从造型与设计的细节上对司机操纵台进行了优化,并提出新的替代方案.     

强梁特殊开孔参数化建模技术

MSC/NASTRAN是我国造船行业公认的有限元软件,它的前后处理器为建立船体三维有限元模型提供了强大的手段,但由于船体结构的复杂性,仍使得船体有限元分析成为非常繁重的工作,故实现参数化建模已成为船体结构分析人员越来越关注的问题.本文以实际工程项目"强梁腹板特殊开孔应力分析及补强方法的研究"为背景,介绍了作者利用PCL语言实现参数化建立强梁特殊开孔的有限元模型的技术,并编制了相应的程序.应用该程序能大大缩短全部方案模型的建模时间,并提高了效率,体现了PCL语言在实现参数化建模方面的优越性.     

系列点声源模拟铁路噪声的误差分析

根据声学基本理论分析了采用3种指向特性的系列点声源,模拟铁路噪声线声源的误差问题,论证了点源模拟误差和长度模拟误差与各种影响参数的定量关系,给出声源模拟法预测铁路列车运行噪声中确定系列点声源的点源间距和总长的方法,解决了铁路建设项目环境影响评价中铁路噪声预测的一个重要技术问题。     

试验数据统计建模研究

针对数据融合技术和仿真试验的难点，对试验数据的建模问题作了分析研究，简要介绍试验数据建模的成果。     

Forecasting telecommuting

Transportation planners increasingly recognize telecommuting as an important trend. But while they often advocate telecommuting as a transportation demand management strategy, transportation planners have made little progress toward incorporating telecommuting into transportation forecasts, at least partly because of the limited data available. In this paper we explore four alternative methodologies for forecasting telecommuting and discuss the kinds of data that must be collected before these methodologies can be applied. The first approach is trend extrapolation, using curves of technological substitution. Sufficient data are currently available to produce forecasts, albeit highly uncertain forecasts, using this approach. However, even with better data this approach does not address underlying factors and trends that will affect the future of telecommuting. As a result, we explore three additional approaches that should produce more reliable forecasts but which require new data and knowledge about telecommuting: analyzing the characteristics of telecommuters in contrast to nontelecommuters, analyzing factors affecting the individual choice to telecommute, and incorporating telecommuting into traditional transportation forecasting models.     

柴油机螺旋进气道稳流试验与CFD计算的对比分析

对某柴油机螺旋进气道进行传统的气道稳流试验,得到了涡流比和流量系数。在与试验条件对等的边界条件下,应用仿真软件FIRE建立了气道的三维仿真模型,对不同气门升程下进气道内的流场进行了CFD计算;对比试验与计算的结果,两者吻合良好。结果表明,仿真计算省时,成本低,便于方案对比,可以获得气道内的流场分布规律;在柴油机螺旋进气道设计开发与性能评价中具有实用价值。     

冷铣刨-热摊铺养护施工机群配置软件的开发

通过对公路沥青路面冷铣刨-热摊铺养护施工设备的优化配置方法和施工参数进行分析,以Microsoft Access 2003为数据库管理工具,以VB6.0为开发语言,研制开发了冷铣刨-热摊铺养护施工机群配置软件系统,为施工单位和管理者进行决策提供支持,从而提高工作效率。     

Exploring the propensity to perform social activities: a social network approach

Conceptual and empirical models of the propensity to perform social activity–travel behavior are described, which incorporate the influence of individuals’ social context, namely their social networks. More explicitly, the conceptual model develops the concepts of egocentric social networks, social activities, and social episodes, and defines the three sets of aspects that influence the propensity to perform social activities: individuals’ personal attributes, social network composition, and information and communication technology interaction with social network members. Using the structural equation modeling (SEM) technique and data recently collected in Toronto, the empirical model tests the effect of these three aspects on the propensity to perform social activities. Results suggest that the social networks framework provides useful insights into the role of physical space, social activity types, communication and information technology use, and the importance of “with whom” the activity was performed with. Overall, explicitly incorporating social networks into the activity–travel behavior modeling framework provides a promising framework to understand social activities and key aspects of the underlying behavioral process. Juan Antonio Carrasco a PhD candidate in Civil Engineering at the University of Toronto, holds a MSc degree in Transportation Engineering from the Pontificia Universidad Católica de Chile. His doctoral research explores the relationships between social networks, activity–travel behavior, and ICTs. His research interests also include microsimulation, land use-transportation, and econometric modeling. Eric J. Miller is Bahen-Tanenbaum Professor of Civil Engineering at the University of Toronto where he is also Director of the Joint Program in Transportation. His research interests include integrated land-use/transportation modeling, activity-based travel modeling, microsimulation and sustainable transportation planning.     

基于ANFIS的轮胎侧向力模型

用自适应神经模糊推理系统(ANFIS)建立了轮胎的侧向力模型,并与反向传播神经网络(BPNN)建模结果作出比较。     

ARMA模型频率估计方法在轴频提取中的应用

轴频提取的前提是对信号频率有较高的估计精度,采用传统的FFT谱估计技术来获得高精度信号频率需要增加计算量;基于自回归-滑动平均ARMA模型的谱估计技术是一种现代高分辨谱估计技术,在小样本、低信噪比状态下具有很好的频率估计性能.文章将这种方法实用于对水下目标辐射噪声谐波频率进行估计,用仿真和实验分析了该方法的性能.