A technical note on evaluating the effectiveness of bus rapid transit with transit signal priority

Transit Signal Priority (TSP) and Bus Rapid Transit (BRT) are innovative Intelligent Transportation System (ITS) tools that can reduce travel times for buses. Combining TSP and BRT can significantly improve bus travel, but can negatively impact network traffic operations. Although TSP has been implemented worldwide, few previous studies holistically examined the effects of using various conditional and unconditional TSP strategies with or without a BRT system. This research simulates multiple TSP and BRT combination scenarios to understand their impact on traffic operations, including crossing street traffic. A test bed along International Drive (I-Drive) in Orlando, Florida, was chosen as the simulation area. Field data collected for this test bed, which included traffic volumes, bus travel times, and traffic signal control data, were used to develop, calibrate, and validate the simulation model. Results showed that BRT with Conditional TSP 3 minutes behind significantly improved travel times, average speed, and average total delay per vehicle for the main through movements compared with no BRT or TSP, with only minor effects on crossing street delays. BRT with Unconditional TSP resulted in significant crossing street delays, especially at major intersections with high traffic demand, indicating that this scenario is impractical for implementation. The simulation suggests that BRT and TSP will be most effective when used in areas where crossing street volumes are low. However, it is unknown how these ITS tools affect pedestrian traffic. Using optimization methods can determine the best strategy to balance transit and pedestrian traffic.     

高分辨率罗兰C天波延迟估计新技术

提出了一种基于特征分解的多信号分类算法估计罗兰C接收机天波延迟的信号处理新技术。它为接收机基准点的实时设置提供了一种新方法。常规接收机为了防止天波干扰，将基准点设置在一个固定位置上，导致基准点处信噪比受包络限制而较低，从而大大增加了对准基准点的时间。利用这项技术，我们在低信噪比条件下分离出了地波和天波的到达时刻。这就使得接收机能根据天波延迟变化实时选择基准点最佳位置，并能利用地波到达时刻进行周期选择。由于此法有助于增加基准点处的信噪比，减少对准基准点的时间，因而能极大地提高现有罗兰C接收机的性能。还显示了新方法较IFFF方法有更高的分辨率。     

基于超高速AD9954的多模式信号的实现

通过对AD9954采用先进DDS技术性能特点的具体分析，利用其可编程幅度、频率、相位给出AD9954在高速调制信号系统中的应用方案，从而较方便容易地实现基于软件无线电技术的各种调制信号。     

关于容许信号点灯电路的探讨

通过对现有自动闭塞区间通过信号机容许信号点灯电路存在问题的分析，根据相关规范，提出解决办法。     

铁路信号综合防雷中接地的具体作法

针对现场实际,对铁路信号综合防雷中地网设置的具体作法进行了探索,阐述了设置地网时应当注意的技术问题。     

基于GPRS的机车信号远程实时监控系统

针对目前铁路机车信号系统监测存在实时性差的缺点，提出了一种基于GPRS无线网络的监测方法。以Atmel公司AT91R40008ARM处理器为核心，配以GR47GPRS模块，设计了GPRS数据发送盒，以实现机车信号信息的实时检测和无线传输。     

机车信号出入库巡更检测系统

介绍了一种采用精细电子巡更的机车信号出入库检测系统。从安全性、经济性、可靠性及可维护性等方面，对该系统在机车信号检测上的应用前景进行了分析。     

一种高精度声呐波束发射系统的设计与实现

为解决传统声呐发射系统利用移位寄存器的冗余效应的设计方法所引起的精度不高问题,介绍一种采用DSP芯片与FPGA芯片结合设计的声呐发射系统的方法.该系统可同时产生多路信号,每路信号均可独立调节、设定,且各路信号可严格同步,并可按要求设定时延控制、循环发射等功能,各路信号间的延时精度可达200 ns,从而为波束发射系统的开发提供了一种新的思路.实践表明,该方法具有实现过程简单、精度较高的特点,适合于工程应用.     

PA6-280柴油机的变工况多目标配气正时优化计算

建立了柴油机废气涡轮前的燃气能量和燃油消耗率的综合评价函数，采用多目标优化的方法，对PA6-280柴油机的进排气正时进行了优化计算，分析了配气正时的调控对柴油机性能的影响。     

新型区间信号双回路供电自动控制器的研制

简要介绍了研制双回路供电自动控制器的必要性,并对其工作原理、主要元器件的选择标准、整体功能等进行了讨论。