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GPS(Global Positioning System)全球定位系统是美国研制并在1994年投入使用的卫星导航与定位系统。其应用技术已遍及国民经济的各个领域。在测量领域,GPS系统已广泛用于大地测量、工程测量、航空摄影测量以及地形测量等各个方面。本文将以青海省公路路网项目为例,概略叙述GPS系统在公路工程控制测量中的应用。 相似文献
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本文以工程试验中抗压强度试验为例,对试验结果的测量不确定度进行了分析、评估;其分析方法和思路对工程测量、工程试验、质量检验中的测量不确定度评估具有一定的指导作用。 相似文献
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文章以GPS RTK测量技术为研究对象,结合南宁伶俐至钦州陆屋公路工程,介绍了GPS RTK测量技术在公路外业测量中的应用方法,并评述了GPS RTK测量技术的优缺点,提出了相应的建议。 相似文献
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港口航道底部浮泥层存在较大的测量难度,为探索切实可行的浮泥层厚度测量技术,以某港航疏浚工程为例,提出以GPS网络RTK技术为依托,应用SDE-28型全数字测深仪高频信号测量浮泥层上界面,使用塔尺测量浮泥层下界面,再展开数据套合计算后确定浮泥层厚度的优化方案;并对该方案在港航河道浮泥层厚度测量中的应用要点展开分析。结果表明,所采用的测深仪各声学通道均具备信号处理模块,施测期间能确保高低频探测过程独立进行,为更好地测定航道底部浮泥层厚度提供了保证。 相似文献
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高填陡坡路堤监控测量是公路建设安全、高效进行的保证。以某山区公路工程为背景,给出了高填陡坡路堤监控的方法,包括:沉降板和位移边桩的制作及埋设、水准点埋设及精度要求、观测频率、施工中观测控制标准、观测成果整理要求。同时根据此工程的测量数据,给出了测量数据的整理、分析方法。 相似文献
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文章介绍了水准仪测微器的基本工作原理、读数方法及在隧道拱顶下沉量测中的应用,指出需掌握其正确的读数方法,以免进入测微器水准仪读数的误区,使其获得结构的真正变形数据,达到隧道施工监控的目的。 相似文献
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研制一种专用于管道外防腐层耐划伤性能的测试仪器,适用于不同管径、不同壁厚和不同防腐层结构.介绍了管道外防腐层耐划伤测试仪的研制过程,详细描述了耐划伤测试仪机械结构、电子电路及系统软件的设计方法,并对测试仪器的可重复性及可靠性与国外设备进行了对比计算.该测试仪在测试平台的稳定性、划针固定和微调结构、配重压力测量和调节、测控电路设计等方面有创新,提高了设备的准确性和稳定性.防腐层的耐划伤测试试验表明:该仪器适用于不同管径、不同壁厚钢质管道的不同防腐层结构的测试,操作简单,维护方便,能够满足防腐涂层耐划伤测试的要求;测试结果较准确,具有可重复性. 相似文献
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Telecommuting and travel: state of the practice,state of the art 总被引:1,自引:0,他引:1
Patricia L. Mokhtarian 《Transportation》1991,18(4):319-342
This paper provides an overview of the status of telecommuting in the United States, especially as it relates to changes in travel behavior. Regarding the state of the practice, the paper discusses some refinements to the definition of telecommuting that have developed through increased operational experience. It reports several policy statements involving telecommuting, and explores the appeal of telecommuting as a public policy instrument. It highlights some trends in the implementation of home-based and work center-based telecommuting, and suggests that visible public-sector involvement has been crucial to the increased activity in this area.In sketching the state of the art, the paper outlines some frequently-stated hypotheses on telecommuting and travel behavior, and summarizes current empirical findings relating to those hypotheses. Finally, it suggests a variety of topics suitable for further research. These include studying factors influencing the ultimate adoption levels of telecommuting; impacts on energy/air quality, mode choice, and location/urban form; interactions with other transportation demand management strategies; relationships to the traditional urban travel demand forecasting process; cost/benefit tradeoffs; and telecommuting centers. 相似文献
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K. W. Axhausen 《运输规划与技术》2013,36(3-4):275-290
Any policy addressing the concerns and trends associated with the impact of travel on the environment should be based on a solid understanding of the activities giving rise to them. While the measurement of the total environment loads by air or noise measurement stations is essential, it needs to be matched by the observation of the human behaviours creating them. This is especially true in the transport sector, which has been rightly or wrongly identified as having the potential to make a substantial contribution to the reduction of air and noise pollution. While the contribution of freight transport is of growing concern and importance, this paper focuses on the measurement of passenger transport throughout. In the past transport planners have largely relied on the travel diary as their prime instrument to measure traveller behaviour. The travel diary is a survey instrument designed to record all movements during the course of one or more days including their relevant details. It is complemented by spearate household and personal forms for recording general information. In the following paper the term travel diary implies all three elements (the diary, the person form and the household form). The remainder of the paper discusses to what extent and how the travel diary can be used to capture data for the assessment of policies directed at reducing the impact of transport on the social and natural environment. The requirements of a travel diary and the potential uses of new technologies in realising such a travel diary are then presented. A brief outlook on the possibilities of reasling such a diary concludes the paper. 相似文献
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This paper analyzes the influence of urban development density on transit network design with stochastic demand by considering two types of services, rapid transit services, such as rail, and flexible services, such as dial-a-ride shuttles. Rapid transit services operate on fixed routes and dedicated lanes, and with fixed schedules, whereas dial-a-ride services can make use of the existing road network, hence are much more economical to implement. It is obvious that the urban development densities to financially sustain these two service types are different. This study integrates these two service networks into one multi-modal network and then determines the optimal combination of these two service types under user equilibrium (UE) flows for a given urban density. Then we investigate the minimum or critical urban density required to financially sustain the rapid transit line(s). The approach of robust optimization is used to address the stochastic demands as captured in a polyhedral uncertainty set, which is then reformulated by its dual problem and incorporated accordingly. The UE principle is represented by a set of variational inequality (VI) constraints. Eventually, the whole problem is linearized and formulated as a mixed-integer linear program. A cutting constraint algorithm is adopted to address the computational difficulty arising from the VI constraints. The paper studies the implications of three different population distribution patterns, two CBD locations, and produces the resultant sequences of adding more rapid transit services as the population density increases. 相似文献
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In order to improve the level of bus service, a field study was undertaken to develop a combined bus comfort model. This paper provides a comprehensive review of the different ways to predict the bus comfort, in addition to the variable experimental techniques used. It was found some environment parameters like noise, vibration, thermal comfort and the acceleration would affect the passengers’ experience. In this model, both the measurement of objective physical parameters and subjective questionnaire survey were conducted to gather the practical environment date, as well as to distribute questionnaires on board city buses during the same trips. By comparing the subjective views of bus passengers to objective physical parameters, a combined bus comfort model was established. This model helps to calculate the concrete value of passengers’ perceived bus comfort. An effective approach integrated the comfort model, measuring instrument and the driver monitor could greatly improve the bus service quality. 相似文献
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Abotalebi Elnaz Ferguson Mark R. Mohamed Moataz Scott Darren M. 《Transportation》2020,47(3):1223-1250
Transportation - This paper reviews the process that led to the development of a national survey instrument used to gather over 20,000 observations across Canada. This survey captured aspects of... 相似文献
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Activity-based modelling approaches require a typical survey instrument which can collect the finer details of activities of each individual over both time and space. This paper focuses on the design of a new survey instrument called an activity-travel diary; examines its method of administration; and analyses activity-travel behaviour in the context of developing countries. The Mumbai Metropolitan Region in India is selected as the study area. With the aim of understanding the activities of each individual over a period of time, a pilot survey was conducted in a continuous time frame for a period of 15 days, followed by a main survey. The analysis of data collected by the instrument reveals some interesting facts regarding the relationships between socioeconomic attributes, activities and trip making behaviour. Identification of interactions among households and other members were also facilitated by the newly designed diary, which is not a well-versed topic for research in the context of a developing economy like Mumbai's. 相似文献