自密实混凝土在地铁顶纵梁上的应用及质量控制

地铁车站工程在车站顶纵梁混凝土浇注施工过程中,遇到了操作空间小、难振捣、浇注不密实等诸多问题,通过使用自密实混凝土,使相关问题得以解决。主要从自密实混凝土的配制应用以及质量控制等方面做了介绍。     

水泥再生基层施工质量控制技术研究

水泥再生基层技术是一种低碳环保的路面修筑技术,结合某试验路施工经验,对水泥再生基层施工中的要点进行归纳分析,研究结果可为提高水泥再生基层的施工质量提供借鉴。     

预应力混凝土箱梁施工

通过对梨树园蒲石河大桥箱梁的预制施工,全面总结了从箱梁立模、混凝土浇注到预应力钢束张拉、灌浆、封锚全过程的施工工艺,提供了相应的施工方法、混凝土配合比、振捣时间和预应力张拉等各种技术数据。     

高速公路沥青混凝土路面平整度的质量控制

影响沥青混凝土路面平整度的因素很多,结合现场的实际环境和条件,对施工各环节易出现的关键问题进行剖析,提出防范措施,规范施工行为,为路面平整度的质量控制提供参考。     

辽宁省交通工程质量检测与数据智能分析平台技术应用

辽宁省目前在建高速公路监理实验室应用并推广《交通工程质量检测与数据智能分析平台》,介绍了该系统了总体技术方案及推广应用具有的重大意义。     

基于AVR单片机的四相步进电机驱动设计

主要介绍了由AVR单片机为核心的四相八拍步进电机的驱动设计,并用电路图、数据表格和子程序的方式说明了四相八拍步进电机的硬件驱动原理和驱动软件的设计实现。采用了35BYJ46型四相八拍步电动机,通过对AVR单片机Atmega8的I/O口编程实现对步进电机的环形分配器驱动编码,采用了达林顿管电路ULN2003驱动设计,通过程序改变步进电机的方向和速度,实现了对步进电机的稳定、可靠控制。     

Dynamic bus holding strategies for schedule reliability: Optimal linear control and performance analysis

As is well known, bus systems are naturally unstable. Without control, buses on a single line tend to bunch, reducing their punctuality in meeting a schedule. Although conventional schedule-based strategies that hold buses at control points can alleviate this problem these methods require too much slack, which slows buses. This delays on-board passengers and increases operating costs.It is shown that dynamic holding strategies based on headways alone cannot help buses adhere to a schedule. Therefore, a family of dynamic holding strategies that use bus arrival deviations from a virtual schedule at the control points is proposed. The virtual schedule is introduced whether the system is run with a published schedule or not. It is shown that with this approach, buses can both closely adhere to a published schedule and maintain regular headways without too much slack.A one-parameter version of the method can be optimized in closed form. This simple method is shown to be near-optimal. To put it in practice, the only data needed in real time are the arrival times of the current bus and the preceding bus at the control point relative to the virtual schedule. The simple method was found to require about 40% less slack than the conventional schedule-based method. When used only to regulate headways it outperforms headway-based methods.     

ISO/TS 22163:2017技术规范变更管理要求在铁路企业的应用

从ISO/TS 22163:2017《铁路应用质量管理体系铁路组织业务管理体系要求:ISO 9001:2015在铁路领域应用的特殊要求》对变更管理的要求出发,介绍变更管理的定义、分类、原则、控制要求等内容.分析典型变更管理流程,为铁路行业相关企业提供借鉴和参考.     

Adaptive traffic signal control with equilibrium constraints under stochastic demand

This study develops a methodology to model transportation network design with signal settings in the presence of demand uncertainty. It is assumed that the total travel demand consists of commuters and infrequent travellers. The commuter travel demand is deterministic, whereas the demand of infrequent travellers is stochastic. Variations in demand contribute to travel time uncertainty and affect commuters’ route choice behaviour. In this paper, we first introduce an equilibrium flow model that takes account of uncertain demand. A two-stage stochastic program is then proposed to formulate the network signal design under demand uncertainty. The optimal control policy derived under the two-stage stochastic program is able to (1) optimize the steady-state network performance in the long run, and (2) respond to short-term demand variations. In the first stage, a base signal control plan with a buffer against variability is introduced to control the equilibrium flow pattern and the resulting steady-state performance. In the second stage, after realizations of the random demand, recourse decisions of adaptive signal settings are determined to address the occasional demand overflows, so as to avoid transient congestion. The overall objective is to minimize the expected total travel time. To solve the two-stage stochastic program, a concept of service reliability associated with the control buffer is introduced. A reliability-based gradient projection algorithm is then developed. Numerical examples are performed to illustrate the properties of the proposed control method as well as its capability of optimizing steady-state performance while adaptively responding to changing traffic flows. Comparison results show that the proposed method exhibits advantages over the traditional mean-value approach in improving network expected total travel times.     

铁路调度工作质量评价及辅助决策系统设计研究

目前铁路调度工作质量评价及辅助决策手段自动化、智能化程度相对滞后,日班计划兑现率较低,制约了调度指挥效益的进一步提升。为提升调度工作质量,提高日班计划、阶段计划一体化编制水平,在阐述铁路调度工作质量评价及辅助决策系统目标的基础上,从表示层、业务逻辑层、数据层3个方面对系统进行总体架构,分析铁路调度工作质量评价及辅助决策系统功能,即:以实现基于全局视野的安全过程卡控,基于大数据架构的调度工作质量评价,跨区段、面向岗位的列车运行图辅助盯控及预测,施工组织可视化管控,面向生产决策的一体化数据统计分析,以提升调度整体工作质量与管理水平。