沥青路面多孔混凝土排水基层施工技术分析

水侵害是造成沥青路面早期破坏的主要因素之一。多孔混凝土是一种性能良好的新型道路基层材料,相应的多孔混凝土排水基层沥青路面是一种新型的路面结构。对多孔混凝土排水基层的施工技术及注意事项进行研究和分析,为该项施工技术的推广应用提供参考经验。     

基于功效系数法的城市公交线网优化模型

城市公共交通线网优化是城市客运交通规划的重要部分之一。对现有公交线网进行优化,可以更有效地利用现有资源,解决城市交通问题。通过对城市公交线网优化的主要内容、优化模式、优化目标以及约束条件的分析,同时兼顾乘客出行时间、线网平均满载率、公交线网密度和公交线网的布局,对整个城市交通系统的影响提出优化目标的函数表达式及相应约束条件的数学表达式,建立公交线网优化的多目标模型。通过对模型的分析,提出可用功效系数法对模型进行寻优和评价。     

新疆兵团道路运输业发展趋势分析

在对新疆生产建设兵团道路运输业现状分析的基础上,通过利用一元线性回归模型、平均增长率法以及灰色预测法三种方法分别对兵团2011～2015年的道路旅客运输量、道路货物运输量、道路旅客运输周转量、道路货物运输周转量等进行预测。结果显示,在未来5年当中道路旅客运输以年均7.7%增长,道路货物运输以年均9.2%增长,道路旅客周转量以年均10.6%增长,道路运输货物周转量以年均12.6%增长。     

一种改进的Jakes’信道模型及仿真

由于无线通信环境中存在的诸多不确定因素以及其在现代无线通信系统中的重要作用，合理的无线信道成为通信系统仿真研究的重要目的。确立信道仿真模型的目的就是为了尽可能的得到实际信道的统计特性，该文针对Jakes提出的信道模型，通过仿真来分析其局限性，并参考其中的谐波叠加（sum of sinusoids，SOS）法，来建立一种采用了随机分支增益、随机初始相位和有条件的随机多普勒频率改进的信道模型。     

复合地层盾构机推进速度SVM预测模型研究

在复合地层盾构法隧道施工中,如何提高盾构机推进速度一直是盾构机设计、施工人员研究的重点。以长沙轨道交通1号线五一广场到营盘路隧道工程为研究背景,现场采集盾构机掘进参数,应用SVM,建立了"五营"区间复合地层盾构机推进速度的预测数学模型,并对模型进行检测,检测结果表明该预测模型对推进速度预测的平均相对误差≤7%,验证了该模型对推进速度预测的有效性。     

Are HOV/eco-lanes a sustainable option to reducing emissions in a medium-sized European city?

Innovative traffic management measures are needed to reduce transportation-related emissions. While in Europe, road lane management has focused mainly on introduction of bus lanes, the conversion to High Occupancy Vehicles (HOV) and eco-lanes (lanes dedicated to vehicles running on alternative fuels) has not been studied comprehensively. The objectives of this research are to: (1) Develop an integrated microscopic modeling platform calibrated with real world data to assess both traffic and emissions impacts of future Traffic Management Strategies (TMS) in an urban area; (2) Evaluate the introduction of HOV/eco-lanes in three different types of roads, freeway, arterial and urban routes, in an European medium-sized city and its effects in terms of emissions and traffic performance. The methodology consists of three distinct phases: (a) Traffic and road inventory data collection; (b) Traffic and emissions simulation using an integrated platform of microscopic simulation; and (c) Evaluation of scenarios. For the baseline scenario, the statistical analysis shows valid results. The results show that HOV and eco-lanes in a medium European city are feasible, and when the Average Occupancy of Vehicles (AOV) increases, on freeways, the majority of vehicles can reduce their travel time (2%) with a positive impact in terms of total emissions (−38% NO_x, −39% HC, −43% CO and −37% CO₂). On urban and arterial corridors, the reduction in emissions could be achieved only if the AOV increases from 1.50 to 1.70 passengers/vehicle. Total emissions of the corridor with an AOV of 1.70 passengers/vehicle can be reduced up to 35–36% for the urban route while the values can be reduced by 36–39% for the arterial road. With the introduction of Hybrid Electric Vehicles (HEV) and Electric Vehicles (EV) it is possible to reduce emissions, although the introduction of eco-lanes did not show significant reductions in emissions. When both policies are simulated together, an emissions improvement is observed for the arterial route and for two of the scenarios.     

桥梁桩基础施工技术探讨

桥梁桩基础是整个桥梁的重要组成部分,稳定夯实的桥梁桩基础对桥梁起到了重要的支撑作用,桥梁桩基础的质量好坏对整座桥梁的工程质量具有直接的影响.以某桥桩基施工为例,探讨钻孔桩施工技术以及需要注意的重要问题,以供同行参考.     

Sensitivity-based uncertainty analysis of a combined travel demand model

Travel demand forecasting is subject to great uncertainties. A systematic uncertainty analysis can provide insights into the level of confidence on the model outputs, and also identify critical sources of uncertainty for enhancing the robustness of the travel demand model. In this paper, we develop a systematic framework for quantitative uncertainty analysis of a combined travel demand model (CTDM) using the analytical sensitivity-based method. The CTDM overcomes limitations of the sequential four-step procedure since it is based on a single unifying rationale. The analytical sensitivity-based method requires less computational effort than the sampling-based method. Meanwhile, the uncertainties stemming from inputs and parameters can be treated separately so that the individual and collective effects of uncertainty on the outputs can be clearly assessed and quantified. Numerical examples are finally used to demonstrate the proposed sensitivity-based uncertainty analysis method for the CTDM.     

应用广义最大覆盖模型进行公路养护应急中心布局选址研究

应用广义最大覆盖模型方法在江西省国省道公路网络中进行公路养护应急中心布局选址,将养护应急中心设置在县级及以上行政中心点上,在点的服务半径已知的条件下,求解如何设立数量最少的点便可覆盖所有区域.     

一种定制型铁路信号监测系统的设计与实现

针对铁路信号业务模式不断变化的特点,设计一种业务定制型铁路信号监测系统,通过提供信号基础元素库及图形化的构建过程,实现铁路信号监测业务的灵活定制。