某轻型货车年代款的设计研究

在综合考虑整车系统要求、法规、制造工艺等前提下,从方案策划、概念设计、工程设计、样车试验等过程对某轻型货车年代款进行设计开发.在设计上应用新的产品开发流程,包括概念设计、油泥模型、逆向工程激光非接触式数据采集、CAE运动及模态分析、快速成型件装配认证、全数字化检具设计等,使得车辆的整体式前围钣、格栅、整体组合前照灯、仪表板、车门等实现了高材料利用率及更加美观实用的效果.     

重庆两江大桥桥梁文化展示内容及方法研究

桥梁是城市的名片,是城市地域文化历史的浓缩与载体。对桥梁文化展现的必要性、展示内容和方法进行分析,并将分析结果与重庆两江大桥桥梁文化展现设计进行对比,提出桥梁文化展现的基本思路。     

城市桥梁色彩景观设计分析--以重庆两江大桥色彩景观设计为例

以重庆东水门长江大桥及千厮门嘉陵江大桥景观设计方案为例,对桥型、桥位周边建筑,重庆城市环境色彩及邻近桥梁色彩进行分析,以探求合理的桥梁色彩景观设计方法,为桥梁色彩设计提供参考。     

台湾高速公路服务区规划设计介绍

高速公路服务区是高速公路工程的重要组成部分之一,它既是为高速公路运营提供各项服务的交通设施,又是在高速公路上开设的内部出入口,对高速公路的行车功能有一定的影响作用.在分析台湾高速公路服务区布局与建设特点的基础上,结合重庆高速公路服务区存在的问题,提出规划设计思路,供同行交流和研讨.     

Modeling a rail transit alignment considering different objectives

An optimization model for station locations for an on-ground rail transit line is developed using different objective functions of demand and cost as both influence the planning of a rail transit alignment. A microscopic analysis is performed to develop a rail transit alignment in a given corridor considering a many-to-one travel demand pattern. A variable demand case is considered as it replicates a realistic scenario for planning a rail transit line. A Genetic Algorithm (GA) based on a Geographical Information System (GIS) database is developed to optimize the station locations for a rail transit alignment. The first objective is to minimize the total system cost per person, which is a function of user cost, operator cost, and location cost. The second objective is to maximize the ridership or the service coverage of the rail transit alignment. The user cost per person is minimized separately as the third objective because the user cost is one of the most important decision-making factors for planning a transit system from the users’ perspective. A transit planner can make an informed decision between various alternatives based on the results obtained using different objective functions. The model is applied in a case study in the Washington, DC area. The optimal locations and sequence of stations obtained using the three objective functions are presented and a comparative study between the results obtained is shown in the paper. In future works we will develop a combinatorial optimization problem using the aforementioned objectives for the rail transit alignment planning and design problem.     

Evaluating web site service quality in public transport: Evidence from Taiwan High Speed Rail

More and more public transport system passengers plan their trips by using website services. The passengers’ perceived service quality of a website plays a crucial role in recognizing the satisfaction of a transportation service chain. This study aims to investigate the passengers’ perception of electronic service quality (e-SQ) delivery through the Taiwan High Speed Rail’s (THSR) website, by adopting the Rasch measurement model to measure a subjective latent construct: perceived e-SQ. The Rasch model can compare person parameters with item parameters, which are then subjected to a logarithmic transformation along a logit scale to clearly identify which e-SQ measurement items are appreciated by certain passengers. Analytical results show substantial differences between the perceived e-SQ of various personal characteristics such as age, income, and trip types. Empirical results also demonstrate that passengers are most satisfied with the website’s accuracy of information and introduction to the THSR stations’ surrounding area, but are not satisfied with instructions when a transaction fails as well as the carriage layout of the THSR. Our analytical results also identify which service items lead to the perceived e-SQ difference between business trip and leisure trip passengers. The relationship between the two main attribute dimensions – quality of transportation information provided and quality of website services – are also further examined. The empirical results can help a transportation system service operator to better understand how passengers perceive e-SQ and to suggest what should be improved.     

地铁信号系统WLAN与LTE车-地无线通信方案对比分析

地铁CBTC信号系统车-地无线通信方案有WLAN和LTE 2种.本文针对这2种不同的车-地通信方案,从无线系统架构、无线设备分布、数据吞吐量、支持的最高列车速度、无线传输性能、抗干扰性能、无线系统的复杂程度等方面进行对比分析,对新建地铁线路及既有采用WLAN方案的线路延伸线的车-地无线通信方案进行选择,具有一定的指导意义.     

普速铁路无缝线路钢轨折断工务应急处置措施探讨

低温季节无缝线路钢轨断轨故障时有发生,制定规范的无缝线路断轨故障应急处置程序,是确保铁路运输安全和畅通的保障。本文就普速无缝线路轨道红光带检查、防护设置、现场操作程序等断轨故障发生后应急处置要领进行阐述,总结迅速抢修注意事项,可为提高相关作业人员断轨应急处置能力提供帮助。     

Effects of new bus and rail rapid transit systems – an international review

Cities worldwide are implementing modern transit systems to improve mobility in the increasingly congested metropolitan areas. Despite much research on the effects of such systems, a comparison of effects across transit modes and countries has not been studied comprehensively. This paper fills this gap in the literature by reviewing and comparing the effects obtained by 86 transit systems around the world, including Bus Rapid Transit (BRT), Light Rail Transit (LRT), metro and heavy rail transit systems. The analysis is twofold by analysing (i) the direct operational effects related to travel time, ridership and modal shifts, and (ii) the indirect strategic effects in terms of effects on property values and urban development. The review confirms the existing literature suggesting that BRT can attract many passengers if travel time reductions are significantly high. This leads to attractive areas surrounding the transit line with increasing property values. Such effects are traditionally associated with attractive rail-based public transport systems. However, a statistical comparison of 41 systems did not show significant deviations between effects on property values resulting from BRT, LRT and metro systems, respectively. Hence, this paper indicates that large strategic effects can be obtained by implementing BRT systems at a much lower cost.     

Characterising Green Light Optimal Speed Advisory trajectories for platoon-based optimisation

Conceptually, a Green Light Optimal Speed Advisory (GLOSA) system suggests speeds to vehicles, allowing them to pass through an intersection during the green interval. In previous papers, a single speed is computed for each vehicle in a range between acceptable minimum and maximum values (for example between standstill and the speed limit). This speed is assumed to be constant until the beginning of the green interval, and sent as advice to the vehicle. The goal is to optimise for a particular objective, whether it be minimisation of emissions (for environmental reasons), fuel usage or delay. This paper generalises the advice given to a vehicle, by optimising for delay over the entire trajectory instead of suggesting an individual speed, regardless of initial conditions – time until green, distance to intersection and initial speed. This may require multiple acceleration manoeuvres, so the advice is sent as a suggested acceleration at each time step. Such advice also takes into account a suitable safety constraint, ensuring that vehicles are always able to stop before the intersection during a red interval, thus safeguarding against last-minute signal control schedule changes. While the algorithms developed primarily minimise delay, they also help to reduce fuel usage and emissions by conserving kinetic energy. Since vehicles travel in platoons, the effectiveness of a GLOSA system is heavily reliant on correctly identifying the leading vehicle that is the first to be given trajectory advice for each cycle. Vehicles naturally form a platoon behind this leading vehicle. A time loop technique is proposed which allows accurate identification of the leader even when there are complex interactions between preceding vehicles. The developed algorithms are ideal for connected autonomous vehicle environments, because computer control allows vehicles’ trajectories to be managed with greater accuracy and ease. However, the advice algorithms can also be used in conjunction with manual control provided Vehicle-to-Infrastructure (V2I) communication is available.