WTB初运行的模拟研究

鉴于初运行所具有的特性及其在列车通信网络中的重要作用,基于初运行原理,提出初运行流程图,并将其分为命名主设备、寻找未命名节点、命名结束和构形分配四个阶段,深入分析了整个初运行过程。以此为基础,利用Java语言,编制出包括加载图片、按钮、线程管理、绘图和初运行五大模块的初运行过程模拟程序,使之能够对初运行的全过程进行步进式地显示,最后给出了软件模拟的部分结果。实现软件模拟初运行过程。     

Mobile phone use while driving: public opinions on restrictions

This paper reviews two road-user surveys on the use of mobile phones on the road in Finland where the mobile phone ownership rate is highest in the world (70% in August 2000). From 1998 to 1999 the proportion of drivers that chose to use a mobile phone while driving rose from 56% to 68%, while the proportion of phone using drivers who experienced dangerous situations due to phone use rose from 44% to 50%. The proportion of drivers who used their phones in some way to benefit safety on the road remained at about 55%. The youngest, novice drivers had the highest level of phone usage of all age categories. Over 48% of the interviewees believed that the government should ban the use of hand-held mobile phones while driving, and another 27% believed that all types of mobile phone use should be banned while driving. Those drivers who used their phones the most each day were more likely to want some form of restrictions, than those who had lower usage. This is a strong message to the elected lawmakers and raises the problem of exactly how regulatory bodies would go about controlling the future growth of new driver support and non-driving related communication devices in road vehicles. It was concluded that legislating for hands-free use only would be a reasonable course of action. Mandating that the current generation of equipment should be optimized for hands-free use should result in future generations of in-vehicle equipment also being optimized for hands-free use as a minimum criterion.     

新一代调度集中（CTC）对无线移动通信的需求分析及实现方案探讨

本文简要介绍了新一代调度集中的主要特点，重点分析其对无线移动通信的要求，并分析了目前常见解决方案各自的利弊，就存在的问题提出了观点。     

Simulation studies of information propagation in a self-organizing distributed traffic information system

This paper investigates the feasibility of a self-organizing, completely distributed traffic information system based upon vehicle-to-vehicle communication technologies. Unlike centralized traffic information systems, the proposed system does not need public infrastructure investment as a prerequisite for implementation. Due to the complexity of the proposed system, simulation is selected as the primary approach in the feasibility studies. A simulation framework is built based on an existing microscopic traffic simulation model for the simulation studies. The critical questions for building the proposed market-driven system are examined both from communication requirements and traffic engineering points of view. Traffic information propagation both in freeway and arterial networks via information exchange among IVC-equipped vehicles is tested within the simulation framework. Results on the probability of successful IVC and traffic information propagation distance obtained from the simulation studies are generated and analyzed under incident-free and incident conditions for various roadway formats and parameter combinations. Comparisons between the speed of the incident information wave and the speed of the corresponding traffic shock wave due to the incident are analyzed for different scenarios as the most crucial aspect of the information propagation as a potential foundation for application in such a decentralized traffic information system.     

铁路车地广播通信系统中喷泉码的应用研究

铁路通信系统具有其特殊的行业应用需求,如高可靠性,低误码率。研究喷泉码(RaptorQ)技术,作为一种前向纠错的编码方式应用于铁路广播通信系统中,可在保证系统误码率的同时,最大限度的利用系统资源。同时,依赖于喷泉码自身的编码特点,译码是否成功仅与接收到信息数量相关,部分信息的丢失不会对应用层信息造成影响。对不同丢包率条件下,达到不同误码率等级要求时所需的译码开销进行仿真,实现对喷泉码性能研究的目的。     

高速列车宽带无线上网方案比较及电气安装要求

针对高速列车无法宽带无线上网的问题,分析比较了3种不同的解决方案和各自对电气安装的要求。车外语音加车内无线局域网,直放站配合无线局域网和微蜂窝RRU拉远这3种方案都能提供高速列车宽带无线上网。但是它们技术方案不同,导致成本、性能、布线难度不一样。可以根据工程要求选择不同的改造方案。     

基于移动导航数据的信号配时反推

在交通管理和评价时,信号配时对监测评价路口运行状态,评价路口配时方案至关重要.但是,大范围的实时信号配时方案的获取尚缺乏简明有效的途径.本文提出两种基于移动导航数据计算固定配时路口信号配时的方法.第一种方法是在不考虑驾驶员驾驶行为差异性时,得到路口红灯和车均延误的关系模型,从而计算某相位的红灯时长.另外一种方法是基于车辆通过停止线的时间,结合本文提出的上升梯度法,得到某阶段红灯时长.本文通过实际的路口案例计算,将预测结果和已知路口的信号配时比较,表明此方法计算得到的红绿灯时长准确度较高,为后续进行路口运行状态和通行能力研究提供了数据支持.     

基于过程现场总线的安全通信的研究与实现

介绍PROFIBUS-DP的通信原理.在此基础上,介绍研究安全通信的系统硬件连接以及其实现安全通信的方法.     

高速铁路智能交通综合信息系统中关键问题的探讨

阐述了在我国实现铁路智能交通综合信息系统的必然性，提出了铁路智能交通综合信息系统的体系结构，强调了需要发展通信信号系统的关键，并着重分析了通信信号系统急需解决的问题。     

侧滑仪与检测工作站通信技术研究

汽车前轮定位参数的正确与否,对汽车的行驶平顺性、安全性、秉坐的舒适性及操纵的灵巧等方面有很大影响.因此,作为前轮定位参数的重要部分--侧滑量的检测在汽车检测系统中占有不可或缺的地位.