基于实例的船舶靠泊操纵技术探讨

船舶靠泊码头操作是驾驶员经常性经历的工作之一,也是操船中事故发生率较高的一项操作.以3个码头靠泊时的体会出发,从制定靠泊计划、了解码头情况、熟知本船性能和控制余速4个方面,进一步总结船舶靠泊码头应注意的事项.     

Categorizing bicycling environments using GPS-based public bicycle speed data

A promising alternative transportation mode to address growing transportation and environmental issues is bicycle transportation, which is human-powered and emission-free. To increase the use of bicycles, it is fundamental to provide bicycle-friendly environments. The scientific assessment of a bicyclist’s perception of roadway environment, safety and comfort is of great interest. This study developed a methodology for categorizing bicycling environments defined by the bicyclist’s perceived level of safety and comfort. Second-by-second bicycle speed data were collected using global positioning systems (GPS) on public bicycles. A set of features representing the level of bicycling environments was extracted from the GPS-based bicycle speed and acceleration data. These data were used as inputs for the proposed categorization algorithm. A support vector machine (SVM), which is a well-known heuristic classifier, was adopted in this study. A promising rate of 81.6% for correct classification demonstrated the technical feasibility of the proposed algorithm. In addition, a framework for bicycle traffic monitoring based on data and outcomes derived from this study was discussed, which is a novel feature for traffic surveillance and monitoring.     

扣件DI弹条非正常部位断裂原因分析及结构优化

通过对DI弹条非正常部位断裂的研究,发现扣件安装时弹条与铁垫板安装孔发生接触,致使弹条在中肢与尾部圆弧过渡区域产生应力集中,发生早期疲劳断裂。本文在研究弹条结构及安装方式的基础上,在弹条的中肢与尾部圆弧过渡区域引入"凹面"结构,对弹条进行结构优化,并通过扣压力和疲劳性能检测、实验室疲劳断裂检验、现场试铺检验等对带有优化"凹面"结构的DI弹条性能进行检测。结果表明:优化后的弹条扣压力和疲劳性能均合格,且能有效抑制因接触产生的非正常部位断裂,提高弹条性能。     

运营高铁车站黄土路基沉降特征及原因分析

针对黄土地区某高铁车站路基沉降病害问题,选取典型区域,采用PS-InSRA技术对变形区域进行监测,获取2017年2月至2019年6月的Sentinel-1A卫星影像数据并与现场勘测结果相结合,分析形变特征和趋势,以指导后续病害治理。结果表明:研究区域路基沉降主要发生在2017年5月至9月和2018年4月至8月两个时间段,春夏季沉降速率较大,秋冬季相对平稳;地基土含水率在13%~26%之间,在地下2 m和4 m为含水率增加速率临界深度,0~2 m范围内的含水率增加较快,2~4 m范围内的含水率增加速率减缓,4~10 m范围内含水率基本稳定;路基部位地基处理影响范围有限,路基侧沟外侧地基土干密度偏小,渗透系数偏大,路基沉降的主要原因为车站场坪地表汇水渗入地基引起路基黄土层湿化变形。     

基于数据驱动的机场水泥混凝土道面性能退化预测

针对机场道面性能退化过程的精确预测问题，本文采用数据驱动的机场道面预测性维护方法，通过指示变量将两种数据集进行联合分析，考虑机场道面性能退化过程受飞行交通量和道面面层厚度的影响，以机场道面性能状况指数衰变的非线性函数为期望函数，建立一种机场道面性能退化双参数预测模型；根据模型的参数估计结果，采用边际效应分析结合预测性能曲线图示，对不同飞行交通量水平和不同道面厚度等级的道面性能退化过程预测进行分析。结果表明，采用数据驱动和非线性混合效应方法，搭载联合估计技术，能较为显著地提高机场道面性能退化预测的精度和效果。     

高速铁路路基全断面沥青混凝土防水封闭结构

提出1种高速铁路路基全断面沥青混凝土防水封闭结构,基于该结构工作状态,分析其主要功能特性,设计碾压密实高模量沥青混凝土。将全断面沥青混凝土防水封闭结构应用于工程试验段,跟踪监测其服役特性。结果表明:试验段轨道结构及路堤基床动力性能均满足规范限值要求;试验段基床含水量维持在8%~18%,受天气影响小,而邻近的纤维混凝土对照段基床含水量为10%~35%,随天气波动显著;试验段沥青混凝土的吸热作用,使得路肩处基床温度较对照段大;试验段路基竖向变形监测值较对照段稍大,但均满足限值要求;试验段沥青混凝土与底座等接触情况良好,无松散剥落等病害,仅在底座板接缝处有数条裂缝,而对照段出现较多的纵横向裂缝,严重影响其防水封闭效果;沥青混凝土修补方便,可维护性高。     

马来西亚ETS米轨干线动车组概述

文章介绍了马来西亚ETS米轨干线动车组的运行线路及运用环境情况,着重分析了车辆主要技术特点及总体性能参数,详细阐述了其主要机械、电气系统与转向架等的设计方案和技术特点。     

Fully autonomous vehicles: analyzing transportation network performance and operating scenarios in the Greater Toronto Area,Canada

Fully autonomous vehicles (AVs) have the potential to considerably change urban mobility in the future. This study simulates potential AV operating scenarios in the Greater Toronto Area (GTA), Canada, and assesses transportation system performance on a regional level. For each scenario, the base capacities of certain types of road links are modified to simulate the theoretical increase in throughput enabled by AV driving behavior. Another scenario examines driverless parking operations in downtown Toronto. Simulation results indicate that the increased attractiveness of freeways relative to other routes leads to slightly increased average travel distance as vehicles divert to access higher capacity road links. Average travel time is found to decrease by up to one-fifth at the 90% AV market penetration level. Concurrently, localized increases in congestion suggest that proactive transportation planning will be needed to mitigate negative consequences of AV adoption, especially in relation to induced demand for personal automobile travel.     

陕西省黄陵县克山病病情8年连续观察

目的　观察陕西省黄陵县克山病 8年来病情及相关因素的变化。方法　选择黄陵县的 6个重病村设立监测点 ,该区居民列为监测对象。 1995年至 2 0 0 2年连续 8年对该监测点克山病的发病情况监测及 3～15岁儿童内环境硒水平进行监测。结果　①潜、慢型克山病的检出率 1995、1997、1999、2 0 0 0和 2 0 0 2年依次为 4 .3%、3.6 %、7.5 %、8.0 %和 8.5 % ;②潜在型克山病的新发生率 1995、1997、1999、2 0 0 0和 2 0 0 2年依次为 5 5 .6 /万、5 3.5 /万、19.5 /万、0 /万和 2 5 /万 ;③全县 8年慢型克山病死亡 2 2例 ,15例死于慢性充血性心力衰竭 (占 6 8.2 % ) ,7例死于猝死 (占 31.8% ) ;④病区 3～ 15岁儿童发硒含量 8年均达到非病区水平。结论　陕西省黄陵县克山病的发病呈平稳低发态势 ,但潜在型克山病仍有新发     

浅议高速公路服务区布局规划

在对高速公路服务区明确定义和分类后,提出服务区的布置方式和合适的用地规模,然后经过分析多方面因素,合理确定服务区的设置间距,并提出服务区在高速公路沿线布局的相关技术准则。