The multi-objective railway timetable rescheduling problem

Unexpected disruptions occur for many reasons in railway networks and cause delays, cancelations, and, eventually, passenger inconvenience. This research focuses on the railway timetable rescheduling problem from a macroscopic point of view in case of large disruptions. The originality of our approach is to integrate three objectives to generate a disposition timetable: the passenger satisfaction, the operational costs and the deviation from the undisrupted timetable. We formulate the problem as an Integer Linear Program that optimizes the first objective and includes $\epsilon$-constraints for the two other ones. By solving the problem for different values of $\epsilon$, the three-dimensional Pareto frontier can be explored to understand the trade-offs among the three objectives. The model includes measures such as canceling, delaying or rerouting the trains of the undisrupted timetable, as well as scheduling emergency trains. Furthermore, passenger flows are adapted dynamically to the new timetable. Computational experiments are performed on a realistic case study based on a heavily used part of the Dutch railway network. The model is able to find optimal solutions in reasonable computational times. The results provide evidence that adopting a demand-oriented approach for the management of disruptions not only is possible, but may lead to significant improvement in passenger satisfaction, associated with a low operational cost of the disposition timetable.     

圆端形沉井内力比较

在沉井截面设计中,针对双孔圆端形截面,通过等截面内力计算得知隔墙与沉井连续处弯矩最大,考虑在隔墙与沉井连续处采用变截面。为节省材料和成本,寻求合理截面,采用等截面与变截面2种截面形式进行设计。以所给工程为例,通过编制电算程序,计算双孔圆端形沉井等截面与变截面的内力,比较和分析2种截面在相同圆弧段半径及同矩形段长度下的内力,以寻找圆端形沉井设计的最优截面形式。     

虹桥综合交通枢纽开发融资策划

虹桥综合交通枢纽是上海城市交通的重大枢纽,属于城市大型交通基础设施.分析了虹桥综合交通枢纽的基本经济属性,对枢纽设施进行了拆分,并根据可经营性、可拆分性将枢纽设施分成4种类型;基于设施分类,对枢纽系统的投资平衡进行了研究,提出了4类设施不同的融资方式,以及由此所形成的投资分工和多元化投资主体结构.     

驼峰编组场纵断面设计

本文介绍一种采用VB语言开发的驼峰纵断面调整的程序,该程序在计算机绘图软件CAD中运行,利用VB语言开发的程序来操纵CAD,使CAD自动绘制纵断面设计图并计算土石方量。     

Determining the optimal number of seasonal adjustment factor groupings when estimating annual average daily traffic and investigating their characteristics

Although cluster analysis is recommended by the US Traffic Monitoring Guide (TMG) to supplement the development of seasonal adjustment factor groupings (SAFGs), the relationships among SAFGs' characteristics remain undiscovered, while the determination of the optimal number of clusters is an ambiguous task exposed to great subjectivity. Statistical indicators provide a mathematical solution by removing engineering judgment without taking into consideration any guidelines or other criteria, necessary for transportation planners to generate ‘practical and sensible’ groupings. The method examined in this study aims to overcome the above weaknesses incorporating into the methodology a series of statistics, recommendations, and previous research findings. The investigation of the relationships among (1) the within-group variation, (2) the total number of sites, (3) the minimum number of stations within a cluster, (4) the optimal number of clusters, and (5) the geographical size of the groups constitutes the main objectives of this research. According to the results, the cluster variability declines as the available number of stations increases. When the minimum number of stations within a cluster increases, the weighted coefficient of variation inflates as well, with the rate of increase depending on sample size. The average number of automatic traffic recorders per cluster is analogous to the sample size, while the optimal number of clusters varies conversely with the minimum number of stations within a cluster. The application developed for the conduct of the analysis minimizes the computational time needed, while it can be easily implemented by engineers to automate the process recommended by the TMG, enhancing the current state of practice.     

基于Simulink模型的电动汽车传动系优化程序设计

简述了电动汽车的动力传动系统的优化设计技术,自行设计了一种优化传动系速比的方法调用AD—VISOR2002仿真软件中的Simulink模型搭建了优化传动系速比的目标函数,详细介绍了优化程序设计的基本原理与程序代码的实现,并通过实例加以说明和验证。     

直线感应电机模型分析与转差频率控制研究

介绍了考虑端部效应后直线感应电机在两相同步旋转坐标系下的数学模型,并对速度与反应板对端部效应的影响进行了分析。在此基础上讨论了直线感应电机转差频率控制方案的可行性,并给出了控制方案。采用Matlab／Simulink构建了直线感应电机数学模型并对其转差频率控制进行了仿真。仿真结果验证了控制方案的可行性。     

城市道路施工图中沥青面层材料说明的企业标准化解决方案

为规范城市道路施工图中沥青面层材料说明的写法，明确设计文件必须的材料指标要求，提升工作效率，并降低设计人员重复繁琐的文本编辑工作，要研发通过软件自动生成沥青面层材料说明的企业标准化解决方案。首先，统计分析目前城市道路施工图中关于沥青面层材料的一般写法与内容，查询相关国家及行业规范的要求，确定说明部分的框架。其次，了解施工、监理、质检验收等相关方对施工图文件中关于沥青面层材料相关内容的使用情况，调研城市道路路面主要病害及产生的原因，统计说明中易产生歧义或指标不清晰带来的施工、验收及运营期病害等问题。最后，形成固定的企业标准说明结构，相关指标参数输入数据库，设计人员使用软件通过点选必要的项目信息自动生成说明文字。