Systematizing international benchmarking for ports

The subject of port efficiency is one of the important issues facing port authorities and policy makers today. A number of studies have been undertaken which compare ports in terms of their efficiency. But any port comparison can only be valid and meaningful if a port's efficiency is compared with a similar port. The principal objective of this paper is to introduce a systematic approach to identifying similar ports based on the technique of principal component analysis. Secondly, it seeks to identify the most important factors underlying the port classification. Lack of awareness of which factors differentiate ports has resulted in an unnecessary collection of data which are of limited use in port classification. This study has identified three groupings of similar ports within which port comparison can be justifiably made. This approach can be used for any future port comparison and can be applied to other areas of activity facing the same difficulty.     

基于有源滤波器和AT供电方式的新型同相牵引供电系统

2台YN,d接线变压器十字交叉构成的AT牵引供电系统,接线复杂,变压器容量利用率低,相邻供电区段必需用分相绝缘器分断,不利于高速铁路运行。由1台YN,d接线变压器加四桥臂有源滤波器构成的新型同相AT牵引供电系统,可以实现同相供电,取消分相绝缘器;可以节省变压器,原边中性点可方便接地;在有源滤波器的作用下,可以实现消除三相不平衡、动态滤除谐波和补偿无功,使变压器容量得到充分利用;由于采用了AT供电方式,因此可以获得综合经济性能优越的通信防护效果。仿真实验也证实了这一点。     

基于GIS的铁路选线智能环境及领域本体建模方法

提出基于GIS的铁路选线智能环境(GBRLIE)的智能选线综合解决方案。铁路选线智能环境的既有研究,以及GIS技术、人工智能技术和其他计算机技术的发展为解决方案的研究奠定了基础。在GBRLIE的知识表达上,本体提供了信息共享、互操作的中间件,可保证知识系统从概念分析到系统建立的概念一致性,能保持数据和知识的语义统一。本体位于GBRLIE的逻辑表示层,包括领域本体、方法本体和应用本体。领域本体是对研究领域可共享和重用静态知识的描述,采用UML和面向对象技术进行表示,可克服专用本体描述语言和表示方法的不足。领域本体的形式化描述把关系和规则当作概念处理,用UML表示本体、概念、关系、规则、约束、公理。应用提出的领域本体表示方法描述了铁路选线几何构成本体,列出选线设计中的部分规则及约束。     

俄罗斯铁路货车空车脱轨研究

介绍了2001年以来俄罗斯铁路货车空车脱轨事故增多的原因,以及防范措施.     

基于面向对象技术的舰船综合电力系统电力网络故障模拟及拓扑跟踪

针对舰船综合电力系统电力网络结构特点,本文实现了基于面向对象技术的对舰船综合电力系统电力网络的拓扑建模。并针对电网故障的随机性特点,在面向对象环境中实现了对随机故障的模拟,同时用深度优先算法进行了快速的拓扑跟踪。算例分析证明了该方法的有效性。     

Ground travel mode choices of air arrivals at regional destinations: The significance of tourism attributes and destination contexts

The aim of this paper is to examine the air leisure arrivals’ ground travel mode choice in the context of their decision to disperse beyond the gateway. A stated choice experiment was designed to examine the dispersal and travel mode choice of leisure visitors arriving on air transport at Cairns. Results show that for a hypothetical public bus alternative, attributes such as ‘sightseeing opportunities’ and ‘driver quality’ were significant for trips made to less known destinations located south of Cairns, compared to destinations north of Cairns. Findings suggest that while travel mode attributes and trip characteristics are significant determinants of the mode choice of air leisure arrivals, the extent of their significance varied markedly across destinations. Although the data examined in this paper were collected in Cairns, this research should be of relevance to many regions interested in understanding the relationship between destination transport and dispersal of air arrivals.     

我国无水港通关模式评价研究

无水港是近年来迅速发展的、与港口具有同样功能的"内陆港"。介绍了国内4个无水港港群发展的现状和我国目前无水港的通关模式。分析了无水港通关模式的优势和社会效益。指出了需要进一步解决的问题。     

大型柔性管节预制过程中控制精度的选择

在沉管管节干舷值影响因素分析的基础上,结合国内沉管隧道的施工经验对某沉管隧道大型柔性管节的预制精度进行了推荐,并给出了预制精度方案下干舷值的变化范围,可为今后沉管隧道管节预制的设计和施工提供参考.     

地面安全监测系统TPDS传感器标定的虚拟仪器技术

介绍了货车运行状态地面安全监测系统(TPDs)传感器静态标定仪的硬件组成及软件设计.标定仪测试软件是基于图形化编程语言--LabVIEW编写的,可以执行在线测量和分析处理,包括数据采集、显示,进行灵敏度、线性度分析和数据存储、报告输出及打印等功能.同时,还具有友好的人机界面.