ATIS�г�ռ���������о�

普遍认为先进的出行者信息系统(ATIS )能够有效地减少拥堵，提高出行者的出行质量.研究表明它所带来的效益并不是随着其市场占有率的增长而持续增加的，本文就此问题做了详细的探讨.首先综述了ATIS市场占有率问题的相关概念，在此基础上，详细介绍了近几年来国内外对ATIS市场占有率问题的研究成果.最后，分析了该领域研究中目前存在和需要进一步研究的问题，并提出了一些有效的改进方法.     

挂篮施工时宽幅混凝土箱梁横向框架的受力分析

以府河大桥主桥70+120+70(m)预应力混凝土连续梁为背景,对挂篮施工过程的箱梁横向框架进行了受力分析.结合分析结果,对大跨径、宽幅预应力混凝土连续梁结构设计提出了一些建议,为以后同类型桥梁设计提供参考.     

三角轻型挂篮在斜拉桥悬臂施工中的应用

结合浙江省舟山市嵊泗三礁港大桥,介绍三角轻型挂篮的结构特征、安装和使用方法,以及在斜拉桥主梁悬臂浇筑中的施工技术。三角轻型挂篮的成功应用,保证了混凝土箱梁浇筑质量。     

Effectiveness of en route traffic information in developing countries using conventional discrete choice and neural‐network models

Providing commuters with traffic information or advising them of alternative routes during traffic incidents can alleviate congestion. For decades, advanced traveler information services (ATIS) have been devised and dedicated to this role. ATIS comprises a wide variety of technologies across the world, including radio traffic information (RTI) advisory service. RTI is common in both developed and developing countries. Although extensive literature and evaluation results of ATISs and RTI are available in developed countries, little attention has been devoted to that in developing countries. This work provides a modeling platform to study drivers' response to en route traffic information provided by Radio‐Payam broadcasting service in Tehran, the capital city of the developing country of Iran. The results are compared with counterpart cases in developed countries. Past studies and this study have employed conventional discrete models for drivers' response, such as ordered logit and ordered probit. This work evaluates the accuracy level of these conventional models in comparison with a developed neural‐network (NN) model, because it has been widely proven that NN models are highly precise. It has also been found that, apart from reliability, the conventional models are within an acceptable level of prediction accuracy compared with the NN models. The results show a high degree of similarities between the case of Tehran and its counterparts in the developing countries. The results also deliver some insights on how to improve or better implement the ATIS technologies. Copyright © 2012 John Wiley & Sons, Ltd.     

基于元胞自动机的VMS诱导信息系统研究

VMS诱导信息系统的特点是系统的性能高度依赖驾驶员对信息的反应，诱导信息类型一直是研究的重点。已有的研究多侧重于将行程时间作为诱导信息，如当前行程时间、预测行程时间。有学者基于两条等长路径尝试将速度信息作为诱导信息，并对最近驶出车辆的行程时间信息和平均速度信息的诱导效果进行对比，结果表明速度诱导信息效果更好。考虑实际路网中．替换路径长度通常不等，文中以元胞自动机为工具，对发布平均行程时间诱导信息和平均速度诱导信息的效果进行模拟，并对结果进行分析。     

Modeling user adoption of advanced traveler information systems: dynamic evolution and stationary equilibrium

This paper models the growth rate and the saturation market penetration level for advanced traveler information system (ATIS) products/services with heterogeneous drivers. The price of using and the benefit gained from ATIS services are considered two key factors in explaining the growth of adoption of ATIS products. The information benefit is measured as the travel time saving between equipped and unequipped drivers and evaluated by a mixed stochastic and deterministic network equilibrium model. A modified logistic type growth model is adopted to describe the cumulative adoption of ATIS products over years. The final stationary equilibrium level of ATIS market penetration is so determined that the value of the information provided will decline to the point at which no new users will find it advantageous to purchase that service. The endogenous growth and stationary equilibrium model of market penetration of ATIS services is useful for forecasting the growth process and the impacts on the system performance of ATIS.     

交通信息系统在高峰期事故瓶颈中影响作用分析

根据驾驶者的行为模式建立了一个路径选择模型及排队模型.在高峰时期发生交通事故的情形下,通过对比行驶车辆在配备车载信息系统和未配备交通信息系统两种情况,分析事故瓶颈引起车辆阻塞占用道路长度与事故处理时间的关系的影响,论证交通信息系统对交通瓶颈的改善作用.通过案例分析予以验证.     

����迹Logit·��ѡ��ģ�͵��Ƶ���Ӧ�ü���֤

提出了一种基于相对阻抗的改进Logit模型,将判断误差的方差修正为与阻抗相关,克服了传统模型因同一分布而导致的等方差问题,并推导出基于相对阻抗的Logit模型的概率计算公式.给出了相对效用的概念在常见改进Logit独立相关性缺陷的模型中的应用.计算实例表明,改进后的模型均能有效解决“长短路”问题,且物理意义明确、计算简单,具有良好的鲁棒性.     

涟水河大桥挂篮悬臂浇筑法施工技术的应用

悬臂施工法是从已建好的桥墩开始对称地、沿桥梁跨径方向逐段施工的方法。该文结合工作实践,针对连续箱梁桥采用挂篮现浇悬臂施工难度大的现状,介绍了涟水河大桥悬臂施工所用的挂蓝类型和特点,通过现场结构体系转换等施工工艺,分析了粱体施工过程中产生挠度的因素、现浇施工与测试、挂篮的拼装与预压、合拢段验算,可供类似桥梁施工参考。     

信息对出行时间的影响研究

在一个不确定性交通网络上,考虑不同风险厌恶程度出行者的出行时间受交通信息的影响,采用出行时间及对出行时间不确定性的偏爱程度建立期望效用函数,研究信息环境下与非信息环境下的期望出行时间,得到如下结论:(1)信息的提供将减少所有出行者的期望出行时间;(2)在信息环境下,风险厌恶程度高的出行者期望出行时间的减少比风险厌恶程度低的出行者期望出行时间减少更显著。并用算例对模型结论加以验证。