贯彻交旅融合发展理念下的公路工程设计新思路

基于交旅融合发展理念,在构建结构合理、功能完善、特色突出、服务优良的旅游交通运输体系的发展趋势下,现以G579线库车-拜城-玉尔滚公路工程建设(二期)项目为例,在分析拟建项目交旅融合发展条件的基础上,总结出基于交旅融合理念的公路工程设计新思路,并从路线布设、工点设计、旅游标志等方面系统论述了设计新思路的具体实施细节,以...     

基于WebGIS的台风信息服务系统研究及应用

我国是一个多台风的国家,国内在将信息技术应用于台风信息的管理和发布方面取得了显著成果。但随着防汛需求的不断提高和信息技术的飞速发展,使得原有研究存在一些局限性。该文建立了囊括1921～1998年间对上海有重要影响的台风以及1999年以来历次台风的数据库,并基于WebGIS构建了台风信息服务系统。系统具有路径自动生成、动态告警、距离量算、风圈半径影响分析、相关信息综合查询、相似路径智能查找等功能,能够为水情预报和防汛指挥部门提供科学决策依据。     

Evolution of public transit modes in a commuter corridor

This paper explores how the selection of public transit modes can be optimized over a planning horizon. This conceptual analysis sacrifices geographic detail in order to better highlight the relations among important factors. First, a set of static models is proposed to identify which type of service, e.g., bus only, rail only, or bus and rail, is the most cost-effective in terms of the average trip cost for given demand. After analyzing essential factors in a long-term planning process, e.g., economies of scale in rail extension and future cost discounting, a dynamic model incorporating such considerations is formulated to optimize the decision over a planning horizon. While analytical solutions can be obtained for some decision variables, the final model is solved with a graphical method by exploring the tradeoffs between the initial and recurring costs. Major findings from this study include: (a) there exists a minimum economic length for a rail line, which can be determined numerically; (b) economies of scale favor large extensions and excess supplied capacity; (c) the rail-only service is largely dominated by the feeder-trunk service, even in the long run.     

计量经济模型预测运量的探讨

根据地量经济学原理及运输业的特点，提出二步预测运量的思路。首先，根据投入产出原理，投入决定国民经济发展水平，又根据运输业的特点，国民经济发展水平决定运量水平，按此思路，能找出运量发生的直接根源，用直接影响运量发生的因素，通过二步计量经济模型，来预测运量。文章根据某省的实际资料，建立了模型，并对模型进行了分析。     

新型耐海水用钢OCrl7Ni12Mo3Cu3及其点蚀行为的显微研究

采用金相显微镜、X射线衍射、扫描电子显微镜（SEM）及扫描隧道显微镜（STM）研究了新型耐海水用钢的显微组织及其点蚀行为。试验结果表明，该钢经1050℃、保温2h固溶处理后，可得到单相的奥氏体组织，具有良好的抗点蚀性能。并通过STM的观测，得到了新型钢的超高分辨三维点蚀形貌图象，为该钢的开发应用奠定了技术基础。     

VTS工程的费用效益后评价方法

本文根据我国主要港口ＶＴＳ的建设特点，对我国ＶＴＳ工程费用效益后评价的方法进行了研究和探讨，给出了费用效益后评价的指标和定量计算公式。通过对几个主要港口的ＶＴＳ后评价，表明该评价方法能够较准确地反映ＶＴＳ的效益评估情况，对今后的ＶＴＳ工程建设和进一步完善ＶＴＳ的运行和管理体制具有一定的指导和借鉴作用。     

A novel approach for assessing the LOS for two‐lane intercity highways under heterogeneous traffic conditions

Performance of two‐lane intercity highways has been evaluated in terms of level of service (LOS) by different researchers. Different follower‐related performance measures, namely, the number of followers (NF), percent followers (PF), follower density (FD) and the number of followers as a proportion of capacity (NFPC) are examined in the present study to define LOS. Data are collected from five sites located in different parts of India. While almost all the past studies used 3‐s headway rule to identify followers suggested by US Highway Capacity Manual, a new methodology is proposed in the current study to identify the followers by analysing speed difference (SD) and the gap between two consecutive vehicles. It is observed that vehicles travel in non‐following condition after a critical gap threshold value of 10 s. By using a SD limit of ?4 km/h to +10 km/h and a gap value of 10 s, followers are identified across all the study sites. Thereafter, different critical gap values ranging from 1.9 s to 4.3 s are observed at the study sites beyond which the probability of not following would increase. Variation in two‐way traffic volume is found to be the main contributory factor which affects the critical gap values. Among all of the performance measures, NFPC shows a strong correlation with two‐way traffic volume followed by FD under heterogeneous traffic condition. Finally, different threshold values of LOS ranges for two‐lane intercity highways are provided by carrying out cluster analysis with the help of NFPC and FD. Copyright © 2017 John Wiley & Sons, Ltd.     

Public transit service operation strategy under indifference thresholds‐based bi‐modal equilibrium

This paper investigates public transit service (fare and frequency) operation strategies in a bi‐modal network with assumption of indifference thresholds‐based travelers' mode choice behavior. Under such behavior, users would switch to a new mode only if its utility is larger than the utility of current mode plus a threshold. The concept of indifference thresholds‐based bi‐modal equilibrium (ITBE) and the properties of the ITBE solution are explicitly proposed. Considering transit operator's different economic objectives (profit‐maximizing, no‐deficit and total system cost‐minimizing), the effect of indifference thresholds on transit fare and frequency schemes is studied. Some numerical experiments are accompanied to verify the theoretical results. Copyright © 2016 John Wiley & Sons, Ltd.     

基于IPSO-XGB的城市轨道交通车站服务质量评价

针对城市轨道交通车站服务质量评价体系不够完善和指标赋权方法较单一的现状,结合当前乘客消费理念及出行习惯,构建基于乘客感知的初始评价指标体系。应用改进粒子群算法(IPSO)与极端梯度提升树(XGB)的混合算法IPSO-XGB计算各指标权重,结合乘客满意度,形成IPA矩阵,得到最终的评价结果,并进一步精简评价指标体系。以长沙地铁五一广场站为例,用分类误差率衡量算法优劣,对车站服务质量进行评价,并将其结果与分类回归树、神经网络等评价算法进行对比。研究结果表明:本文提出的IPSO-XGB评价算法的分类误差率最小,可降至3.85%。     

CBTC应用环境下TD-LTE承载网络的QoS(服务质量)增强措施研究

从减少同频干扰和邻频干扰、增加频谱效率和数据传输速率、提高系统通用性和可靠性等技术优势出发,分析了TD-LTE(分时长期演进)技术应用于CBTC(基于通信的列车自动控制)系统的可行性与必要性。简要介绍了基于TD-LTE承载网络的CBTC系统框架,并分别从控制平面和业务平面对该框架的QoS(服务质量)机制进行了论述。针对CBTC系统的实施提出LTE(长期演进)系统核心网(EPC)冗余、LTE基站冗余与终端设备(CPE)冗余备份等措施,保障TD-LTE承载网络的QoS等级。