简析铁路数字视频监控系统

介绍视频监控系统发展主要经历的3个阶段:模拟视频监控、基于编码器的数字视频监控以及基于TCP/IP网络的数字视频监控。着重分析基于TCP/IP网络的铁路数字视频监控系统的组成及功能。     

认真贯彻《铁路图像通信设计规范》,积极推进铁路综合视频监控系统建设

论述《铁路图像通信设计规范》的编制过程和意义,从规范的主要内容和适用范围等方面强调执行规范的必要性,重点阐述在规范贯彻中的注意事项,提出问题并给出建议,使规范在执行过程中得到进一步完善,推动铁路综合视频监控系统建设。     

铁路应急通信系统探讨

分析现有铁路应急通信接入系统的各种接入方式,根据不同现场和条件,选择相应的接入方式。同时,加大铁路应急通信队伍的建设,培养高素质、高标准的应急通信抢修人员。     

安庆长江铁路大桥防船撞研究

根据美国阿肯色河桥和广东九江大桥船撞非通航孔桥墩时的速度,质疑美国公路桥梁设计规范中"船偏离航线速度正比下降"的方法。符合实际地总结出"失舵不失速"的工况,结合安庆铁路桥的防撞研究,对船撞桥速度的选取、船撞力和需设防桥墩数目的确定提出了见解,并对防撞方案进行了探讨。     

公路景观设计中理念的提炼与体现方法研究

以公路景观的功能需求为切入点,详细分析公路景观的特征与作用。基于对公路景观特征和作用的分析,认为公路景观设计要满足舒适的功能需求,体现公路景观的地域特色,要有理念作先行指导。文章系统地总结了理念的提炼与体现方法,并结合南京南站集疏运道路景观绿化设计的实例,对理念的提炼与体现作了例证解析,充分体现理念作为设计的灵魂,在公路景观设计中的重要作用。     

Experimental investigations on the damping effect due to passengers on flexural vibrations of railway vehicle carbody and basic studies on the mimicry of the effect with simple substitutions

The effect of passengers on a railway vehicle is usually considered as additional mass in designing a carbody. However, previous studies by means of stationary excitation tests or running tests using actual vehicles indicate that passengers behave not as mass but as damping. In this paper, the authors examined the passengers' damping effect under controlled excitation conditions on a roller rig through a series of excitation tests using a commuter-type vehicle. Large and multi-modal reductions of flexural vibrations of the carbody were observed when passengers existed. Influences of the number of passengers, distributions and postures of passengers were investigated. The authors also tried to mimic the damping effect by passengers using flexible tanks filled with fluids. Three kinds of fluids which have different viscosities have been tested. As a result of the excitation tests, good vibration reduction effects were observed by applying those tanks, and it has been found that the flexible tanks filled with fluids bring about vibration reduction effect (including multi-modal reduction) which is equal to or rather better than the case of similar mass of passengers in the carbody; the difference of viscosity gave little affect on the damping abilities. From these measurement results, a possibility of realising effective damping devices against flexural vibrations of railway vehicle carbodies representing passengers damping effect, in a simple, economical and environmental friendly way, has been demonstrated.     

A parallel algorithm for train rescheduling

One of the crucial factors in achieving a high punctuality in railway traffic systems, is the ability to effectively reschedule the trains when disturbances occur. The railway traffic rescheduling problem is a complex task to solve both from a practical and a computational perspective. Problems of practically relevant sizes have typically a very large search space, making them time-consuming to solve even for state-of-the-art optimization solvers. Though competitive algorithmic approaches are a widespread topic of research, not much research has been done to explore the opportunities and challenges in parallelizing them. This paper presents a parallel algorithm to efficiently solve the real-time railway rescheduling problem on a multi-core parallel architecture. We devised (1) an effective way to represent the solution space as a binary tree and (2) a novel sequential heuristic algorithm based on a depth-first search (DFS) strategy that quickly traverses the tree. Based on that, we designed a parallel algorithm for a multi-core architecture, which proved to be 10.5 times faster than the sequential algorithm even when run on a single processing core. When executed on a parallel machine with 8 cores, the speed further increased by a factor of 4.68 and every disturbance scenario in the considered case study was solved within 6 s. We conclude that for the problem under consideration, though a sequential DFS approach is fast in several disturbance scenarios, it is notably slower in many other disturbance scenarios. The parallel DFS approach that combines a DFS with simultaneous breadth-wise tree exploration, while being much faster on an average, is also consistently fast across all scenarios.     

Prediction of ground vibration amplitudes due to urban railway traffic using quantitative and qualitative field data

The growth of railway transport in urban areas has lead to an increase in ground vibrations enhancing their negative environmental impact. Therefore is mandatory to predict and control ground vibrations. This work presents a methodology for the determination of prediction models of ground vibration amplitudes due to railway train circulation in urban environments. Using quantitative predictors (train speed and distance) and qualitative predictors (railway track type, dominant geology and building type), being the use of the latter predictors justified by the fact that, most frequently, quantitative parameters are very difficult to obtain in the urban environment due to their characterization. Thus, a detailed statistical study based on the proposal and validation of multiple linear regression models, is successfully applied in order to predict vibration amplitudes produced by railway train circulation, in the considered domain, as function of quantitative and qualitative predictors, easily obtained in field work. A multiple linear regression model for ground vibration prediction due to underground railway traffic has been presented for the Lisbon area.     

雪峰山特长隧道沟槽盖板塑钢模具施工技术

结合雪峰山特长隧道沟槽盖板施工,介绍采用塑钢模具生产沟槽盖板的工艺流程、技术要点和质量控制措施。运用塑钢模具进行沟槽盖板生产效果较好,可在当前及未来预制混凝土构件施工中进一步推广运用。     

桥建合一玻璃幕墙结构动力特性仿真分析

高速铁路客运站房大型幕墙是一种桥建合一的结构体系,由于玻璃幕墙体系与列车轨道梁紧密相联,高速列车通过时可能引起玻璃幕墙共振的问题。因此,在设计幕墙结构体系时,行车振动对玻璃幕墙结构体系的影响必须予以考虑。以某高速铁路站房玻璃幕墙结构为研究对象,运用有限元方法进行数值动力仿真分析,分析结果表明:行车振动荷载不会使幕墙结构产生共振;双边列车通行相比单边列车通行,幕墙结构产生的平面外振动位移要大;当行车振动荷载激振方式为竖向力激振时,竖向激振荷载作用下幕墙结构的平面外振动位移很小。