Development and evaluation of a statistically reliable traffic counting program

This paper reviews the existing procedures to compute the seasonal factors, growth factors, and the number of automatic traffic recorder stations (ATRs) for developing a statistically reliable traffic counting program. The review is based on, (i) theoretical evaluation of the procedures, (ii) analysis of the results obtained from applying these procedures to extensive real life data, and (iii) experience of past researchers with these methods. The paper primarily deals with existing statistical procedures for determining seasonal factors, since it is believed that these factors play the most important role in estimating Annual Average Daily Traffic (AADTs) from short counts. The procedure of cluster analysis (which is most commonly used to determine seasonal factors) is critically reviewed. The shortcomings of this method motivated the development of a different statistical procedure, based on regression analysis, to determine seasonal factors. It is shown that this newly developed method gives better results than the cluster analysis techniques. Furthermore, separate sections are dedicated to a thorough analysis of determination of number of ATR stations and computation of growth factors.     

基于GRNN的GSM-R场强覆盖预测算法

在比较Hata模型修正方法和GRNN算法场强覆盖预测效果的基础上,仿真分析了训练集构成和平滑因子选择对GRNN算法预测效果的影响,给出了训练集构成和平滑因子选择的方法;提出了电波传播环境相似系数来表征GRNN模型在不同环境下的适用性。仿真结果表明,两种传播环境的相似系数越大,由一种环境下测试数据确定的GRNN在另一环境下的预测精度越高。     

基于社交网络的民航旅客偏好建模

从社会网络的视角，提出了一种旅客个体偏好与关系偏好相结合的建模方法．首先，从旅客的历史出行记录中，构建基于共同出行关系的旅客社会网络；然后，构建旅客个体偏好模型和旅客关系偏好模型；最后，基于旅客偏好模型给旅客推荐座位．在民航领域的一个真实的数据集上进行了实验，证明本文提出的偏好模型能够有机地将旅客个体偏好与关系偏好结合起来，较好地描述旅客对航班座位的偏好．     

南宁市交通管理和控制系统优化方案分析工具的建立

交通仿真是采用计算机数字模型来反映复杂的交通现象,对交通运动随时间和空间的变化进行跟踪描述和分析。不同精度的交通仿真模型有不同的优缺点,要客观的评估城市的交通管理和控制系统优化措施,应将不同精度的模型配合,作为分析工具。本次研究采用中宏观的SATURN作为主导模型,对南宁市的宏观的交通进行整体分析,以及对不同交通改善方案进行评估。选用TSIS、SYNCHRO交通仿真软件作为辅助的交通分析工具,对局部地区的交通及信号配时作较为具体的分析,以利于本研究针对各种建议方案进行客观性的整合分析与应用。     

级配碎石回弹变形特性

级配碎石具有非线性的应力-应变特性,回弹模量是有效描述这一特性的参数,通过室内动三轴试验能够得到较好的模拟级配碎石回弹模量的模型。分析了影响级配碎石回弹变形特性的各种因素,并进行了试验验证。通过数据拟合发现,Uzan模型能更好地反映级配碎石的非线性回弹变形特性,且模型中的回归参数与级配中小于0.075mm筛孔的质量分数有一定的关联性。并针对影响级配碎石回弹模量的两个重要参数：级配中小于0.075mm筛孔的质量分数和含水质量分数,提出相应的取值范围建议。     

汽车操纵稳定性主客观评价数据的一种处理方法

汽车操纵稳定性主客观评价之间的相关性分析是汽车技术的重要课题。提出了汽车操纵稳定性主客观评价数据的一种处理方法．通过回归分析筛选客观参数，运用BP神经网络建立相关性模型，验证结果说明了该方法的可行性。     

基于非参数回归的快速路行程速度短期预测算法

基于北京市快速路上的检测器所采集的历史数据，经过数据筛选，剔除判别，小波滤噪平稳处理，聚类分析等过程，建立了交通状态演变系列的历史样本数据库。基于所构建的历史数据库，通过数值试验，确定了状态向量、距离匹配原则，K近邻值等参量，构建了一种基于K近邻的非参数回归短时交通预测模型，实现了对路段行程速度的短时预测。最后，利用随机选取的历史数据系列对预测模型的精度进行了检验。结果表明，预测算法的精度可以达到90％以上，可以很好地满足ITS应用系统对于交通预测数据的精度要求。     

Multi-objective optimization of quarter-car models with a passive or semi-active suspension system

A systematic methodology is applied in an effort to select optimum values for the suspension damping and stiffness parameters of two degrees of freedom quarter-car models, subjected to road excitation. First, models involving passive suspension dampers with constant or dual rate characteristics are considered. In addition, models with semi-active suspensions are also examined. Moreover, special emphasis is put in modeling possible temporary separations of the wheel from the ground. For all these models, appropriate methodologies are employed for capturing the motions of the vehicle resulting from passing with a constant horizontal speed over roads involving an isolated or a distributed geometric irregularity. The optimization process is based on three suitable performance criteria, related to ride comfort, suspension travel and road holding of the vehicle and yielding the most important suspension stiffness and damping parameters. As these criteria are conflicting, a suitable multi-objective optimization methodology is set up and applied. As a result, a series of diagrams with typical numerical results are presented and compared in both the corresponding objective spaces (in the form of classical Pareto fronts) and parameter spaces.     

Biodynamic responses of seated pregnant subjects exposed to vertical vibrations in driving conditions

A pregnant woman's body is a very sophisticated dynamic system that is sensitive to whole-body vibrations in a sitting posture. While much effort has been devoted to vibration effects on non-pregnant seated persons, little research has been devoted to the biodynamic responses of seated pregnant women exposed to vertical vibrations, especially in driving conditions. In this study a thorough survey of lumped-parameter models for non-pregnant seated persons is implemented. According to the literature the mathematical models adequate for representing the increase in mass due to pregnancy are proposed and evaluated systematically. On the basis of an analytical study and experimental validation, the six-degree-of-freedom model modified from the non-linear model proposed by Muksian and Nash is recommended. In addition, the recommended pregnant model is further integrated with two-dimensional half-car and three-dimensional full-car models to assess the responses of pregnant drivers or passengers exposed to vertical vibrations due to road unevenness. It is believed that the study presented in this report provides a profound understanding of biodynamic responses of seated pregnant women and that it may offer vehicle engineers a good reference in the design of vehicle suspension systems.     

设置纵隔板钢桥面双层铺装拉应力逼近式研究

以现行《公路工程技术标准》（JTGB01-2003）为依据，结合钢桥面铺装的几何特征、力学特性，建立设置纵隔板的钢桥面双层铺装拉应力三维有限元计算模型。在结构设计参数常用取值范围内，对设置纵隔板钢桥面双层铺装的拉应力关键影响因素进行正交敏感性分析：通过逐步线性回归方法拟和出钢桥面双层铺装拉应力的近似计算公式，使得铺装层车载响应隐含式显示化：同时，通过有限元计算和回归拟舍分析，对标准单轴双轮轴载作用下拉应力的计算公式进行修正，得单轴双轮组各级轴载作用下钢桥面双层铺装拉应力的计算通式，其精度很好，能满足工程设计和理论研究的需要。研究结果可为钢桥面双层铺装结构设计提供近似计算的新方法，