基于f(x)4800微机快速精确测设路线点位的新方法

该新方法是基于f(χ)4800微机,利用程序把整条路线点位的坐标转换到相应路线平面上的大地坐标,再利用两点大地坐标与某点极坐标的转换原理配合测距仪确定路线各点点位的一种新方法,该方法快速精确随意实用,在公路勘测设计中起到较好的效果。     

桥梁挠度精密水准测量方法探讨

阐述了使用精密水准方法进行桥梁挠度测量的基本原理,结合工程实例比较了3种精密水准挠度观测方法的精度,证明了精密水准方法进行桥梁挠度测量的优点和实用价值.     

日本物流调查的经验与借鉴

物流调查是物流设施规划与政策制定的重要基础。物流数据统计发展滞后已成为制约中国物流业发展的重要瓶颈。通过梳理日本在物流调查方面的工作进展,总结其在调查制度保障、组织模式、调查方案、调查内容及方法等方面的特点。针对中国物流行业发展现状,提出具体建议:加快开展货运需求调查的前瞻性研究,规范并指导企业构建统一的物流信息数据与平台,远期将货运调查纳入综合交通调查体系等。     

天津市居民出行特征分析与交通政策探讨

依据天津市居民出行调查的有关数据,通过对出行强度、出行方式、出行距离、出行成本等系列指标总结归纳出天津市城市居民出行的规律、变化特征及其原因,并与我国其他部分城市的居民出行资料进行对比分析,针对未来发展趋势对天津市城市交通发展提出相应的对策与建议。     

浅谈GPS技术与高等级公路测量

全球定位系统为公路勘测设计工作者提供了一个可靠的提高外业测量精度及进度的工具,随着GPS越来越多地出现在人们的生产、生活中,这一先进的测量手段会被更广泛地应用到公路勘测工作中,从而可提高作业效率,缩短设计周期,推动交通事业的发展和公路的建设.     

桥梁管理系统概观

国内外桥梁管理系统概况及现状,以及今后研究发展的思考。     

自由设站放样测量在轨道交通连续刚构PC梁架设中的应用

芜湖轨道交通二号线是国内外首次采用跨坐式连续刚构PC梁的轨道交通项目,相较于国内外现有轨道交通项目的跨坐式简支PC梁,在梁体安装精度、线路平顺性控制、施工技术难度等方面均优于跨坐式简支PC梁。介绍了跨坐式连续刚构PC梁架设中自由设站放样测量控制网的测设原理、布点方法及布点形式,利用自由设站放样测量方法设站灵活、放样精度高等特点,结合自主研发的专用放样工装设备,解决了轻轨跨坐式连续刚构PC梁架设中测量精度不稳定、高程上桥困难、作业时遮挡严重、测量人员安全风险大、多榀梁连接平顺性差等测量难题,可将轨道梁中线偏差控制在3 mm以内,轨道梁中心变化率控制在1.5 mm/1.5 m以内,线路超高情况下的角度公差控制在±1/8°以内。实践证明:自由设站放样测量能够满足轨道PC梁精调施工定位的精度要求,且效率高、精度高、安全性高,在同类项目中具有推广和应用价值。     

Automated parking surveys from a LIDAR equipped vehicle

Parking surveys provide quantitative data describing the spatial and temporal utilization of parking spaces within an area of interest. These surveys are important tools for parking supply management and infrastructure planning. Parking studies have typically been performed by tabulating observations by hand, limiting temporal resolution due to high labor cost. This paper investigates the possibility of automating the data gathering and information extraction in a proof of concept study using a two-dimensional scanning Light Detection and Ranging (LIDAR) sensor mounted on a vehicle, though the work is compatible with other ranging sensors, e.g., stereo vision. This study examines parallel parking in the opposing direction of travel. The ranging measurements are processed to estimate the location of the curb and the presence of objects in the road. Occlusion and location reasoning are then applied to determine which of the objects are vehicles, and whether a given vehicle is parked or is in the traffic-stream. The occupancy of the parking area, vehicle size, and vehicle-to-vehicle gaps are then measured. The algorithm was applied to an area with unmarked, on-street parking near a large university campus. Vehicle counts from 29 trips over 4 years were compared against concurrent ground truth with favorable results. The approach can also be applied to monitor parking in the direction of travel, eliminating the possibility of occlusions and simplifying the processing.     

Tracking daily travel; Assessing discrepancies between GPS-derived and self-reported travel patterns

Global Positioning Systems (GPS) technologies have been used in conjunction with traditional one- or two-day travel diaries to audit respondent reporting patterns, but we used GPS-based monitoring to conduct the first assessment to our knowledge of travel reporting patterns using a seven-day travel log instrument, which could reduce response burden and provide multiple-day, policy-relevant information for evaluation studies. We found substantial agreement between participant-reported daily travel patterns and GPS-derived patterns among 116 adult residents of a largely low-income and non-white transportation corridor in urbanized Los Angeles in 2011–2013. For all modes, the average difference between daily GPS- and log-derived trip counts was only about 0.39 trips and the average difference between daily GPS- and log-derived walking duration was about −11.8 min. We found that the probability that a day would be associated with agreement or discrepancies between these measurement tools varied by travel mode and participant socio-demographic characteristics. Future research is needed to investigate the potential and limitations of this and other self-report instruments for a larger sample and a wider range of population groups and travel patterns.     

进口游艇初次检验及存在的问题

针对进口游艇在国内进行初次检验时存在的诸多问题,结合实际检验情况介绍24 m以下进口游艇的初次检验流程和检验内容,分析检验过程中存在的常见问题并提出解决方案。