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151.
GPS在城市测绘中的应用 总被引:1,自引:0,他引:1
常莉玲 《铁路工程造价管理》2007,22(5):36-39
此文简述了全球定位系统(GPS)的基本结构和测量原理,总结了GPS用于工程测量所具有的特点,介绍了GPS在城市测绘中的应用实例,并通过具体实例说明了GPS作为一种快速、高精度的现代测绘手段已经能够很好地应用于基础测量工作中。 相似文献
152.
Michiel C. J. Bliemer Mark P. H. Raadsen Luuk J. N. Brederode Michael G. H. Bell Luc J. J. Wismans Mike J. Smith 《运输评论》2017,37(1):56-78
This paper presents a review and classification of traffic assignment models for strategic transport planning purposes by using concepts analogous to genetics in biology. Traffic assignment models share the same theoretical framework (DNA), but differ in capability (genes). We argue that all traffic assignment models can be described by three genes. The first gene determines the spatial capability (unrestricted, capacity restrained, capacity constrained, and capacity and storage constrained) described by four spatial assumptions (shape of the fundamental diagram, capacity constraints, storage constraints, and turn flow restrictions). The second gene determines the temporal capability (static, semi-dynamic, and dynamic) described by three temporal assumptions (wave speeds, vehicle propagation speeds, and residual traffic transfer). The third gene determines the behavioural capability (all-or-nothing, one shot, and equilibrium) described by two behavioural assumptions (decision-making and travel time consideration). This classification provides a deeper understanding of the often implicit assumptions made in traffic assignment models described in the literature. It further allows for comparing different models in terms of functionality, and paves the way for developing novel traffic assignment models. 相似文献
153.
张兴容 《铁道劳动安全卫生与环保》1999,26(3):194-197
为减少火灾事故,介绍了“工厂火灾、爆炸场所危险度综合评价法”,“道氏法”是该法的基础。分析了“道氏法”的不足,而提出了固定危险和现实补偿的综合性计算方法。还通过实例记述了新方法的优点、基本原理和应用方法。该法能用于评价工厂企业危险设备、装置与场所的火灾、爆炸危险程度。 相似文献
154.
针对粉煤灰的传统分级评价指标(比表面积指标),不能够完整反应出粉煤灰活性的问题,在室内通过大量实验对粉煤灰的活性测试方法及评价进行了研究。研究中选取了9种不同类型的粉煤灰,运用不同方法对活性进行了测试。在对比细度以及活性度指标基础上,提出了粉煤灰活性指数指标HH,该指标将粉煤灰的外部宏观细度控制指标(比表面积)及内部活性控制指标(活性度)有机地结合在一起。最后实测了HH与二灰砂砾早期强度之间的关系,强度试验结果表明,该指标能够用于评价粉煤灰的活性,并且测试方法简单,利于推广应用。 相似文献
155.
The European Community has provided valuable support to short sea shipping through various programs and legislation. This
paper analyses the situation while focusing on the Mediterranean Sea and suggests solutions for addressing the short sea shipping
problems in this special region. The biggest challenge for all sides in the comingyears will be the replacement of the existing
fleet. The study presented herein gives an insightful and collective picture of the situation, while focusing on the Greek
owned short sea vessels. 相似文献
156.
我国的锚链轮以往都是根据苏联的指导性技术文件PC-246-52进行设计制造的,该锚链轮对锚链的制造误差反应很敏感,在工厂台架试验和实船使用中反映不少问题,其中跳链现象较为普遍,不少制造厂在锚机出厂前采用打磨堆焊等方法来弥补原链轮齿形的不足。 本文所介绍的锚链轮的几何计算和力学分析方法,先后经过了φ40、φ43、φ46、φ57、φ66等几挡的试验鉴定,都得到工作平稳、无冲击、无跳链的满意结果,在浙江海运局的一万吨运煤船和上海海运局的五千吨油轮的实船使用中也得到同样结果。根据本文计算方法编制的专业标准“锚链轮”CB~*3179-83已由全国船舶标准化委员会甲板机械分委会第三次全会审查通过。 相似文献
157.
视屏作业对视觉功能及行为功能影响的观察 总被引:2,自引:0,他引:2
为了进一步观察视屏作业对人体健康的影响,选29名视屏操作人员,使其连续工作4h,于工前和工后分别测定调节近点、简单反应时以及闪光融合频率,结果看到工后调节近点延长,视觉运动反应时延长,闪光融合频率降低。提示视屏作业对人的视觉功能及心理状态可以产生一定影响。 相似文献
158.
P. F. Sweatman P. N. Joubert 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1976,5(3):155-170
Driver steering performance in a simple circular lane-keeping task, as dependent on the directional response characteristics of the vehicle, was measured. Response Surface Methodology models of steering performance are presented. Several canonical variables describe the drivers responses to vehicle changes. Clear-cut optimum vehicle characteristics cannot be determined, but certain combinations of vehicle characteristics are seen to be undesirable for various reasons related to theoretical mechanisms of driver steering control. 相似文献
159.
Edward N. Skomal 《先进运输杂志》1984,18(3):259-277
Through an examination of the dependence of several key performance parameters of a public bus system upon Automatic Vehicle Location (AVL) estimation accuracy, it becomes possible to place in perspective the value of AVL technology to improved public conveyance performance. Important bus transportation system performance measures dependent upon AVL estimation accuracy are: (1) Headway Control Error; (2) Time-Of-Passage Error, and (3) Required Layover Reserve. An analytical model of the dependence of these bus system performance measures upon AVL estimation error has been constructed. In addition, error models of three basic types of AVL systems, i.e., dead reckoning, proximity, and radio location have been developed and validated by experimental comparisons. By employing both sets of models, i.e. for the bus transport and AVL systems it becomes possible to recommend appropriate AVL technologies that best meet the performance requirements of a public bus service. The accompanying text synopsizes the noted models and provides an example of their use. 相似文献
160.
W. Kortü m D. N. Wormley Professor 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1981,10(4):285-317
The technical state-of-the-art of ground transportation vehicles interacting with flexible, perturbed guideway systems is reviewed with emphasis on high-speed passenger-carrying systems. Currently available modelling, analysis, and simulation techniques as well as parametric results illustrating the dominant interaction dynamics are summarized. Experimental studies and correlations of field data with analytical results are described and areas in which further research is required are identified. 相似文献