货车转向架下部限界及压吨检测机的研制

对铁路货车转向架下部限界及压吨检测机的设计原理和应用状况进行了简要的介绍,该设备的研制成功提高了转K2型转向架的生产质量和效率,同时,该设备也能用于K5、K6等型转向架的检测。     

钩耳孔双面加工专用机床的研制

介绍了钩耳孔双面专用加工机床的结构原理和应用状况。     

某航道桥下部结构受船舶撞击后安全性能评估及修复

为评估航道桥下部结构的船撞安全性,以遭受船撞的某内河航道桥为研究对象,采用有限元方法和相关规范计算受撞击的5号桥墩自身水平抗力、船撞力、墩顶位移,并从墩顶位移和桥墩抗力两方面对受撞桥墩的安全性进行评估。结果表明:5号桥墩的横桥向和顺桥向抗力均由桩基强度控制,分别为2528 kN和1142 kN;事故船撞击工况下,墩顶最大横桥向和顺桥向位移分别为7.6 mm、13.4 mm,满足位移限值要求;沿横桥向和顺桥向的船撞安全系数分别为1.67和0.94,顺桥向的自身抗力不足以抵抗瞬时船撞力,导致桥墩桩基础受损,建议采用增大截面法对受损桩基础进行加固补强,并设置独立防撞墩以保障桥梁结构安全。基于分析过程,总结了桥梁下部结构船撞安全评估的一般流程。     

快速城市化地区公交规划方法研究

目前中国许多地区进入快速城市化发展阶段,在长期城乡二元格局影响下,这些地区形成独特的公交需求特性.本文研究了快速城市化地区社会经济发展特性和公交统筹发展要求.根据公交线路服务特性将公交线路分为城乡公交线路和城区公交线路两类,提出了基于层次分析的快速城市化地区公共交通线网规划方法.通过张家港市公交规划的实例分析,体现出该方法适应地区发展趋势以及城乡统筹发展的战略要求.     

Estimating the value of risk reductions for car drivers when pedestrians are involved: a case study in Spain

We estimated the benefits associated with reducing fatal and severe injuries from traffic accidents using a stated choice experiment where choice situations were generated through a statistically efficient design. Specifically, the risk variables were defined as the expected annual number of vehicle car-users that suffered their death or were severely injured in a traffic accident. In addition, and differing from previous research, the number of pedestrians that died or were severely injured in traffic accidents per year was also included as a risk attribute in the choice experiment, to attempt at measuring drivers’ willingness to pay to reduce the risk of hitting pedestrians in a crash. The empirical setting was a choice of route for a particular trip that a sample of car drivers periodically undertakes in Tenerife, Spain. Models were estimated accounting for random taste heterogeneity and pseudo-panel data correlation. The median of the distribution of simulated parameters was used to obtain a representative measure for the monetary valuation of risk reductions. We found that the ratio between the values of reducing the risk of suffering a serious injury and that of reducing a fatality was approximately 18 %. Further, and quite novel, we also found that the value of reducing a pedestrian fatality was 39 % of the value of reducing a car occupant fatality.     

Users’ perceptions and willingness to pay in interurban toll roads: identifying differences across regions from a nationwide survey in Spain

Users’ acceptability is considered one of the key drivers for the successful implementation of transport policy measures. This is especially crucial in the case of toll roads since they are financed through drivers’ contributions. Previous literature in this field has mainly focused on measuring users’ attitudes towards urban congestion pricing strategies. However limited research has been developed concerning interurban toll roads. Previous research shows that socioeconomic variables are not conclusive to explain users’ perceptions towards tolls. By contrast, other drivers such as regional differences seem to play a more important role, especially when charging conditions within the same nation greatly vary across regions. This paper analyzes regional differences in users’ attitudes within an asymmetrical distribution of the toll road network across regions. Based on a nationwide survey conducted to road users in interurban toll roads in Spain, we develop both a binomial logit and a censored regression (tobit) model to explore drivers’ perceptions and willingness to pay. The research concludes that users from regions with a more extensive tolled network generally show a more negative attitude towards charges, but not necessarily a lower willingness to pay. The paper also points out that an asymmetrical distribution of toll roads across regions may result in negative perceptions among those users perceiving to be unfairly treated when compared to citizens in other regions.     

Drivers of transit service loyalty considering heterogeneity between user segments

Users’ loyalty to public transit service is fundamental to promote its popularity in the transportation market. A four-step analytical framework is advanced to investigate the importance of service attributes that heterogeneous transit user segments place on their public transit service loyalty, measured in terms of overall satisfaction and re-use intention. Critical service attributes perceived by transit users that are relevant for loyalty enhancement are explicitly determined, which vary between user segments. It is suggested that the design of strategies aimed to promote the use of public transit by increasing user loyalty towards transit service be targeted at specific attributes that contribute most to loyalty and specific user segments whose original loyalty level is significantly different to others.     

河床边界条件改变对强约束型分汊河道冲刷调整的影响

通过实测资料分析的方法,以宜都河道为例,研究了水库蓄水后强约束型分汉河道的冲刷调整规律.在此基础上,进而通过概化模型试验,研究强约束性分汊河道中,河床边界条件的变化对分汊河道水流运动和冲刷调整规律的影响.研究表明:1)由于水库蓄水后河床发生剧烈的冲刷调整,将导致河道河床边界条件特别是两汊高程差的变化,分流格局随之改变;2)河道边界条件发生变化,水流动力轴线可以由稳定于一汊转化为两汉交替,其冲刷调整形式也从一汉冲刷占优转化为两汊冲刷交替占优;3)分汊河道在水库蓄水初期的剧烈调整过程及其河床边界条件的变化一定程度上影响着分汊河道的发展趋势,要充分认识分汊河道在水库蓄水初期剧烈调整过程中所可能出现的问题,引导其朝好的方向发展.     

无线Ad-Hoc网络密钥分发和认证机制研究

针对Ad Hoc网络没有管理中心,资源受限等特点,解决了Ad-Hoc网络面临的新的安全问题,使Ad-Hoc网络得到更广泛的应用.结合基于身份加密和门限秘密共享两个基本理论,提出了一个适用于Ad-Hoc网络、没有管理中心的分布式密钥分发和认证方案.其优点是:减少了运算量,节省了存储空间和带宽,并无需在网络形成之前假设密钥已经分发完毕,从而有效解决了Ad-Hoc网络安全中密钥管理的问题.     

交通运输支撑新型城镇化发展战略研究

交通运输在推进城镇化发展中发挥着基础性和引导性作用。国家新型城镇化规划对交通运输发展提出了新的更高要求,本文从加强规划引领、突出工作重点和强化改革创新三方面提出了交通运输支撑新型城镇化发展的战略任务。