基于实用的一种网络列车运行图计算方法

在对列车运动轨迹有限制性和相邻列车约束性等列车运行图特点进行分析的基础上,构造了了运行图时空局域内设置窗口,并通过窗口的滚动动态地完成列车运行图求解的时空局域计算方法。运行该算法研制开发的计算机编图系统在我国１９９７年和１９９８年列车运行图编制工作中得到应用。结果表明,该算法计算速度快,实用效果好,是计算机编制实用列车运行图的一种有效方法。     

国内独立特大桥梁收费标准取值空间研究

针对目前国内独立特大桥梁收费标准确定困难的局面,以青岛海湾大桥为例,通过对其收费标准取值空间研究过程进行归纳总结,首次提出了成本费用计量模型确定取值空间的方法,可为后续类似项目研究提供参考。     

论大温差干旱地区混凝土桥梁裂缝预防措施

在大温差干旱环境的影响下，大温差干旱地区尤其是新疆地区的混凝土桥梁容易产生裂缝，严重影响桥梁的安全使用。针对新疆大温差干旱地区特点，分析混凝土桥梁开裂问题，讨论在大温差干旱环境下，混凝土桥梁的设计方案和使用材料选择应考虑的因素，以提高混凝土桥梁的抗裂能力及桥梁工程的质量。     

Electric vehicles: How much range is required for a day’s driving?

One full year of high-resolution driving data from 484 instrumented gasoline vehicles in the US is used to analyze daily driving patterns, and from those infer the range requirements of electric vehicles (EVs). We conservatively assume that EV drivers would not change their current gasoline-fueled driving patterns and that they would charge only once daily, typically at home overnight. Next, the market is segmented into those drivers for whom a limited-range vehicle would meet every day’s range need, and those who could meet their daily range need only if they make adaptations on some days. Adaptations, for example, could mean they have to either recharge during the day, borrow a liquid-fueled vehicle, or save some errands for the subsequent day. From this analysis, with the stated assumptions, we infer the potential market share for limited-range vehicles. For example, we find that 9% of the vehicles in the sample never exceeded 100 miles in one day, and 21% never exceeded 150 miles in one day. These drivers presumably could substitute a limited-range vehicle, like electric vehicles now on the market, for their current gasoline vehicle without any adaptation in their driving at all. For drivers who are willing to make adaptations on 2 days a year, the same 100 mile range EV would meet the needs of 17% of drivers, and if they are willing to adapt every other month (six times a year), it would work for 32% of drivers. Thus, it appears that even modest electric vehicles with today’s limited battery range, if marketed correctly to segments with appropriate driving behavior, comprise a large enough market for substantial vehicle sales. An additional analysis examines driving versus parking by time of day. On the average weekday at 5 pm, only 15% of the vehicles in the sample are on the road; at no time during the year are fewer than 75% of vehicles parked. Also, because the return trip home is widely spread in time, even if all cars plug in and begin charging immediately when they arrive home and park, the increased demand on the electric system is less problematic than prior analyses have suggested.     

The limited scope of seaborne cargo liability regime: new political–economic environments in the 21st century

ABSTRACT

Since the 1920s, seaborne cargo liability regimes have introduced a small number of mandatory rules into international carriage of goods by sea, through the Hague–Visby Rules, to restrict freedom of contract. These rules worked within a limited scope to offset imperfect competition in the shipping markets. However, the recent Hamburg and Rotterdam Rules attempted to extend this scope of seaborne cargo liability regime, which seems to be more extensive than is desirable. This article compares and examines the shipping sub-sectors’ environment and maritime economics over the past century up to date. The new business patterns of the shipping sub-sectors, the rising influence of developing countries, and the containerisation are creating new shipping environments for this area of law. Compared with previous decades, imperfect competition is only found in a smaller number of areas within the shipping markets nowadays. This article argues that only a limited scope of application is needed for international seaborne cargo liability regime. Thus, these new economic and political realities call for innovative modifications to the recent rules regarding the scope of application, and future regime should refocus international uniformity on a limited scope.     

裂隙岩体隧道排水影响范围数值试验研究

隧道排水影响范围一直是难以突破的水文地质问题,直接关系到隧道施工及运营对地下水环境的影响程度.以石太客运专线石板山隧道为例,采用非均质、各向异性等效连续介质渗流模型进行瞬态分析,研究了隧道排水影响半径与施工过程、水文地质因素、工程因素及降雨入渗补给因素的关系.研究结果表明,地层渗透系数、降雨入渗补给量及洞顶含水层厚度影...     

基于图像识别与追踪技术的高速公路交通事件有效检测范围

针对视频交通事件检测器的有效检测范围目前在行业内产生的广泛争议,结合摄像机安装高度、安装角度、摄像机性能指标,通过理论计算和试验验证,得到视频交通事件检测系统对相关交通事件的合理检测范围,从而为高速公路全程视频监控系统外场监控摄像机的布设间距、布设方式提供数据支持,实现高速公路全程无盲区智能化监控识别。计算结果表明,对于小汽车停驶等交通事件,其有效检测距离大于1 000 m的传统说法是不准确的,目前的技术水平很难达到,其合理检测距离应该在500 m左右,试验数据验证了这一说法,但视频交通事件检测系统的有效检测距离后续会随着摄像机性能的不断增强而有所提高,从而满足高速公路监控系统不断提高的监控需求。     

高速公路线形三维空间综合指标与运行车速的关系模型

为准确预测高速公路运行车速,以平、纵线形综合指标为主,横断面线形指标作为修正的方式,考虑桥梁、隧道等结构物的影响,建立包括曲率、曲率变化率、曲线转角、纵坡度、车道宽度等指标的公路线形三维空间综合指标描述函数;注重运行车速的连续性变化及驾驶员视觉需求,确定车辆行驶中前方100 m至250 m有效注视范围为前方线形对车速的...     

NPS6100SHEV增程式电动客车设计

通过对NPS6100SHEV增程式电动客车的动力匹配、发电机组匹配、电池容量计算和控制策略分析,提出增程式电动客车的总体设计要求和一般设计方法。