双目测距技术在调车作业中的 研究与应用

为实现调车作业视频监控与测距的目的,设计一种用于调车顶送作业的双目测距系统,其通过安装于机车车厢的双目摄像机,采集机车已挂车厢与待挂车厢之间实时视频并测量其距离。在OpenCV计算机视觉库与Windows平台下,使用张正友标定法对双目摄像机进行标定,并获得畸变校正后的图像与摄像机参数。通过SGBM特征匹配算法实现车厢目标特征提取与立体匹配。最后利用三维重建方法获得深度信息。系统分别在实验室环境与现场环境下进行实验,现场实验结果表明,测距结果比实际距离稍偏大,最大误差小于1 m,满足实际现场环境要求,可有效地辅助人工瞭望进行调车作业。     

天津地铁网络化运营管理的探索和思考

目前天津地铁即将由单线运营转入网络化运营模式,如何充分结合天津地铁线网规划,确定合理的网络化运营模式,确保地铁网络运营的安全、高效,以及如何体现网络化运营模式的社会、经济价值,已成为地铁运营管理面临的新课题。结合天津地铁1号线的运营管理实践经验,分析网络化运营模式对管理体制、运营组织、维修模式、资源共享等方面的要求,为天津地铁网络化运营管理提供思路。     

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既有研究已经论证高速公路独有的运营特点，包括双能力现象。双能力现象表明，高速公路在自由运行(非排队式)条件下比在排队条件下具有更大能力。在孤立的匝道区，双能力现象的存在，决定了匝道控制在减缓高速公路和匝道交通延迟的效率。本文进一步探讨了微观仿真模型(VISSIM)是否能够在分析现象有关特征的基础上，校准复制双能力现象。本文指出，微观模拟模型用于研究匝道控制延误评价时，必须具有再现双能力现象的能力，否则就会得到错误的结论。本文发现大多数微观模拟模型，例如VISSIM，尽管使用了传统的跟弛理论，但不能自动展示双能力现象。然而，如果在VISSIM中使用一组特殊的编码参数就能再现双能力现象。利用VISSIM模型，本文分析了匝道控制和双能力现象的特征，发现匝道控制减小了双能力值的差距，尤其是采用排队政策时。由于高速公路在自由运行状态下的能力难以评佑，本文建议可用有排队状态下的能力值来代替。     

Demonstration of reduced airport congestion through pushback rate control

Airport surface congestion results in significant increases in taxi times, fuel burn and emissions at major airports. This paper describes the field tests of a congestion control strategy at Boston Logan International Airport. The approach determines a suggested rate to meter pushbacks from the gate, in order to prevent the airport surface from entering congested states and to reduce the time that flights spend with engines on while taxiing to the runway. The field trials demonstrated that significant benefits were achievable through such a strategy: during eight four-hour tests conducted during August and September 2010, fuel use was reduced by an estimated 12,250–14,500 kg (4000–4700 US gallons), while aircraft gate pushback times were increased by an average of only 4.4 min for the 247 flights that were held at the gate.     

“一带一路”国家高速铁路新建线路技术规章体系构建研究

随着“一带一路”倡议的推进和中国铁路“走出去”战略的实施,铁路技术规章体系国际化的要求日益迫切。从我国技术规章体系入手,以印度尼西亚、泰国为主要分析对象,分析我国技术规章应用的适应性,提出以单一层次技术规章体系为核心,将车务、机务、工务、供电、车辆等专业合并为运营管理、动车组运用维护、固定设施维护和信息系统4个部分的体系架构,并指出各个部分应最少具有的技术规章以及其对应参考的国内技术规章,为“一带一路”国家高速铁路新建线路规章建设提供参考。     

Analysis of the operational energy efficiency for inland river ships

This paper looks at the energy consumption and green house gas emissions of inland river shipping, and compares them with the performance of seagoing ships. The analysis is based on a case study of container shipping on the Yangtze River, China. Data were collected under both calm water and real navigation conditions, and energy efficiency operation indices under these conditions are calculated and analyzed. We find that the navigation environment can influence significantly the operational energy efficiency of inland river ships.     

一种连铸连轧低碳低合金钢板的组织特征

利用光学显微镜、直读光谱仪和电子探针研究了一种用连铸连轧工艺生产的低碳低合金钢板的组织特征及成分偏析.结果表明：该钢板的显微组织以珠光体/铁素体带状组织为主要特征,并且随距钢板表面距离增加,带状组织中珠光体比例增加,铁素体平均晶粒尺寸增大.锰含量沿垂直带状组织方向波动,在珠光体条带内含量较高,而在铁素体条带内含量相对较低.钢板中心偏析明显,形成较多长条状硫化物夹杂.     

Road pricing: some further comments

This paper extends the discussion of certain problems associated with road pricing raised in an earlier contribution to this journal. Firstly it is shown that where the value of time varies between different groups of traffic using the same congested road, optimal road pricing requires price discrimination between the groups such that those with the lowest value of time pay the highest charge and suffer the greatest losses. However, a uniform price based on an “equity” value of time would reduce the relative distributional effects. Secondly the paper takes up the suggestion that queueing (and by extension congestion) may be positively helpful in the allocation of resources and shows that this is not in general correct although there are situations in which the use of queueing alongside conventional pricing may have a role to play. Finally it is argued that governments’ apparent lack of enthusiasm for road pricing stems as much from political considerations as the more technical problems of applying it.     

Measuring the performance of intermodal freight terminals

As the interface point between road and rail, intermodal freight terminals (IFTs) are critical elements in the total freight distribution chain. This paper addresses the twin objectives of reducing freight transport costs and improving customer service by putting forward a number of indicators designed to measure the performance of IFTs. Each of the three major performance areas, namely customer service, operational efficiency and terminal productivity are discussed in detail.

A methodology is put forward which enables operating strategies to be evaluated. Computer simulation is used in order to arrive at strategies which reduce operating and capital costs and satisfy customer service requirements. The simulation model outputs include performance measures related to customer service such as mean waiting times required for loading and unloading of containers, as well as productivity measures of terminal operations such as lifting equipment utilisation.     

绿色低碳港口评价指标体系研究与应用

结合我国港口实际,探讨分析了绿色低碳港口的内涵和主要特征,研究构建了一套基于综合性指标、系统性指标、管理性指标、特色性指标等4大类指标的绿色低碳港口评价指标体系,并提出了相应测评方法及标准。以广州港为案例,分别对2013年发展现状水平和2016年、2020年规划水平开展了实证评价,验证了指标体系的科学有效性。