通信机房的建设及防雷击措施

作者长期在通信行业从事一线建设工作,总结工作中的经验得失,着重介绍无人机房的合理选择、规划及机房建设中应着重注意的防雷击措施。     

铁路通信信号电源视频监控技术的应用及分析

结合工程实际,对铁路通信信号电源视频监控系统进行了全面介绍和分析,对工程中存在的问题通过试验分析得出针对性的解决方案,并就铁路电力视频监控技术的发展进行有益的探讨。     

轨道交通无线通信系统的引入与场强覆盖分析

无线通信不仅应满足城市轨道交通内部专用运营管理和业务需求,而且应提供公共移动通信服务,方便人民群众。那么,除了必须设置专用无线通信系统外,如何引入民用无线通信系统、如何避免相互影响以及系统设备共用等问题的解决,将保证无线通信质量的要求,避免无线通信系统的无序、重复建设和浪费资源。     

城轨通信网的可靠性设计

城轨通信网对可靠性的要求越来越高,通过对系统的网络各层次的可靠性分析,提出解决城轨通信网可靠性设计的方法。     

汽车总线通信协议探讨与比较

针对汽车电子控制系统和车载多媒体系统，探讨了汽车总线系统通信协议的技术特点和发展趋势。在对各类汽车总线进行比较和探讨的基础上，对其应用现状进行了分析。综合汽车工业特点对汽车总线协议的统一问题作了探讨。     

回复反射器的理论

回复反射器以其独特的过反射性能广泛应用于交通器材领域，在保证行车安全方面发挥着重要作用。本文详细论述了回复反射器的反光原理、制造技术及反光性能检测技术，指出了回复反射器在汽车工程的应用中应注意的事项。     

Estimating traffic volumes for signalized intersections using connected vehicle data

Recently connected vehicle (CV) technology has received significant attention thanks to active pilot deployments supported by the US Department of Transportation (USDOT). At signalized intersections, CVs may serve as mobile sensors, providing opportunities of reducing dependencies on conventional vehicle detectors for signal operation. However, most of the existing studies mainly focus on scenarios that penetration rates of CVs reach certain level, e.g., 25%, which may not be feasible in the near future. How to utilize data from a small number of CVs to improve traffic signal operation remains an open question. In this work, we develop an approach to estimate traffic volume, a key input to many signal optimization algorithms, using GPS trajectory data from CV or navigation devices under low market penetration rates. To estimate traffic volumes, we model vehicle arrivals at signalized intersections as a time-dependent Poisson process, which can account for signal coordination. The estimation problem is formulated as a maximum likelihood problem given multiple observed trajectories from CVs approaching to the intersection. An expectation maximization (EM) procedure is derived to solve the estimation problem. Two case studies were conducted to validate our estimation algorithm. One uses the CV data from the Safety Pilot Model Deployment (SPMD) project, in which around 2800 CVs were deployed in the City of Ann Arbor, MI. The other uses vehicle trajectory data from users of a commercial navigation service in China. Mean absolute percentage error (MAPE) of the estimation is found to be 9–12%, based on benchmark data manually collected and data from loop detectors. Considering the existing scale of CV deployments, the proposed approach could be of significant help to traffic management agencies for evaluating and operating traffic signals, paving the way of using CVs for detector-free signal operation in the future.     

赤木文库藏琉球官话课本《广应官话》中三则清代闽琉交流史料考述

赤木文库本《广应官话》中保留了三则清代闽琉交流史料,一则是见于《历代宝案》的闽县林合兴商船杠椇清册,属于雍正十年(1732)中琉海难救助史料;另一则是雍乾时期闽中进士刘敬与和琉球人的友好交往记录;最后一则是闽地流行的《新刻官话汇解释义音注》等官话正音书的引文,属于乾嘉时期闽琉文化交流的史料。这些史料一方面说明琉球官话课本语料来源的复杂性,另一方面也体现出其在闽琉交流史研究中的特殊性。     

基于CBTC控制的全自动驾驶系统

主要介绍全自动驾驶(FAO)系统的发展和应用情况、系统的组成和特点,并提出引进采用该系统需要注意的问题。     

驾驶过程中手机使用行为数据采集及分析

驾驶过程中使用手机的行为存在安全隐患,是当今导致交通安全事故的原因之一。文章借助于信息技术开发出采集使用手机行为数据的App,从真实数据出发,客观地分析驾驶员在开车过程中使用手机这一不良驾驶行为的覆盖程度及危险程度,并提出将手机使用行为作为驾驶风险评价因子。