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671.
船舶航行安全评估主要研究船舶平台安全与海洋环境相互之间的关系.海洋环境影响船舶安全航行的空间特性决定了船舶航行安全评价适合采用定量和空间分析相结合的地理信息系统(GIS:Graphic Information System)技术,相对传统的地图分析,基于GIS技术的船舶航行安全评估在方法上有质的突破. 相似文献
672.
The scheduling operations of many paratransit agencies in the United States are undertaken manually. Those customers who are eligible to travel call in their requests the day before the trip is needed. As the trip requests are received, they are entered into a list of unscheduled trips. In order to schedule these trips, the scheduler must first determine the number of drivers and shuttle buses that are available as well as the time of availability of each. The scheduler must then try to match the rides that are in “similar” areas around the “same” time to place together on the driver's schedule. As new trip requests are made, the schedulers must adjust the trips that are already scheduled to try and schedule as many trips as possible in the most efficient way. By developing a system that would improve the scheduling system operations of, in this case, DART (Delaware Administration for Regional Transit) First State Paratransit, customers can expect to receive better service that will improve their ability to travel throughout the community. Some devices that could also improve the operations of paratransit agencies are described in this paper, such as satellite‐based Global Positioning System (GPS), radio communication systems, mobile computers, radio frequency‐based data communication systems, internet web pages, automated paratransit information systems, and card‐based data storage and transfer media. However, because paratransit systems are difficult to operate cost‐efficiently, the optimum and most cost‐efficient device must be selected. The system chosen for DART First State Paratransit includes the use of a relational database management system (RDMS) and a transportation Geographic Information System (GIS). RDMS keeps track of the database information as well as the scheduled trips and the GIS is ideal for analyzing both geographic and temporal data. This system is shown to be superior to the manual system. 相似文献
673.
Both the geographic information system (GIS) and transportation modeling environments have seen continually developing analytic concepts and techniques. However, these developments have seldom resulted in the integration of GISs and transportation models. This paper explores the potential inherent in merging of these environments through a systematic investigation of the fundamental basis of integration. To do this, the traditional four step transportation modeling process is extended to include input and output steps. We then define functional components for GIS data handling — data management, manipulation, and analysis. The steps of modeling are matched against the list of GIS data handling functions within a matrix‐based framework. GIS functions that enhance a land‐use based urban transportation modeling process are then categorized. Conclusions are drawn and directions for future developments are discussed. 相似文献
674.
黄剑 《铁路通信信号工程技术》2008,5(1):5-7
本文介绍了基于交叉感应环线的列车控制系统地面发送设备的原理及安全性,对发送设备的各个功能模块进行了详细的说明。 相似文献
675.
按照"高标准、讲科学、不懈怠"的要求,本文提出了到2012年铁路信息化实现的目标和重点推进的10个方面工作以及构建铁路网络与信息安全保障体系、建立铁路信息系统运行维护机制、造就铁路信息化人才队伍的途径,旨在全面提升铁路信息化工作科学化水平,为建设和谐铁路、实现铁路现代化提供强有力的技术支撑和保障。 相似文献
676.
María Castro Luis Iglesias José A. Sánchez Luis Ambrosio 《Transportation Research Part C: Emerging Technologies》2011,19(6):997-1005
Analyzing the distance visible to a driver on the highway is important for traffic safety, especially in maneuvers such as emergency stops, when passing another vehicle or when vehicles cross at intersections. This analysis is necessary not only in the design phase of highways, but also when they are in service. For its use in this last phase, a procedure supported by a Geographic Information System (GIS) has been implemented that determines the highway distances visible to the driver. The use of a GIS allows the sight distance analysis to be integrated with other analyses related to traffic safety, such as crash and design consistency analyses. In this way, more complete analyses could be made and costs shared. Additionally, with the procedure proposed it is possible to use data regarding the trajectory of a vehicle obtained on a highway with a Global Positioning System (GPS) device. This application is very useful when highway design data are not available. The procedure developed and its application in a case study are presented in this article. 相似文献
677.
为了评估施工期高速公路隧道衬砌结构技术状况,文章运用层次分析法建立由目标层、因素层和指标层构成的递阶层次结构模型,分析影响隧道衬砌结构的各种不确定性因素;采用物元理论、模糊集合论和信息熵理论,构建熵权模糊物元评估模型.工程实例应用结果表明,交工前隧道结构技术状况为IA,衬砌破损程度等级为一般;衬砌裂缝和衬砌背后空洞是影响评估结果的最主要因素.研究认为:该评估方法考虑了指标因子的不确定性,将主观权重与客观权重相结合,避免了传统评判方法中的主观随意性,所得结果更加符合客观实际. 相似文献
678.
针对当前交通规划海量数据多源异构、数据源分散、无统一平台管理及数据获取困难等问题,提出建立基于GIS及交通规划思想与技术的交通规划信息系统。拟定了整体架构,提出了从整体上规划和设计架构于子系统的开发模式,制定了适用于交通规划的数据结构,明确了数据对象间的相互关系,实现了GIS信息系统与EMME3模型的数据交换与集成,总结了关键问题及其处理方法。最后,通过实践应用,阐述了系统在交通规划及建设中的重要作用。 相似文献
679.
随着新奥法在隧道施工中的广泛应用,光面爆破也随之被广泛应用于隧道开挖工程中,通过对岭口隧道爆破工程中光面爆破的设计及施工技术的阐述,提出了光面爆破相关参数的选择方法、施工要求,总结了爆破安全与措施. 相似文献
680.