一种用于超带宽无线通信系统的天线设计实现

文章提出了一种用于超带宽无线通信系统的天线结构,即在介质基片的接地板上开圆环缝隙,采用微带线耦合馈电方法设计,并通过仿真分析和加工实测,证实该天线性能满足超带宽无线通信系统对天线的要求。     

大型水池后浇带设计及施工

介绍了大型水池类结构考虑温度应力时的设计方法及对于超长水池的各种处理方法。结合某污水处理工程的实例,介绍了大型水池后浇带设计及施工,可为同类型工程设计及施工提供参考。     

A multi-path progression model for synchronization of arterial traffic signals

To contend with congestion and spillback on commuting arterials, serving as connectors between freeway and surface-street flows, this paper presents three multi-path progression models to offer progression bands for multiple critical path-flows contributing to the high volume in each arterial link. The first proposed model is a direct extension of MAXBAND under a predetermined phasing plan, but using the path-flow data to yield the progression bands. The second model further takes the phase sequence at each intersection as a decision variable, and concurrently optimizes the signal plans with offsets for the entire arterial. Due to the competing nature of multi-path progression flows over the same green duration, the third model is proposed with a function to automatically select the optimal number of paths in their bandwidths maximization process. The results of extensive simulation studies have shown that the proposed models outperform conventional design methods, such as MAXBAND or TRANSYT, especially for those arterials with multiple heavy path-flows. The research results from this study have also reflected the need to collect more traffic pattern data such as major path-flow volumes, in addition to the typical intersection volume counts.     

UHF移动通信技术在汽车分队指挥中的应用展望

分析了汽车分队信息化指挥通信系统的现状,指出了当前该领域在实践运用过程中存在的薄弱环节,介绍了UHF移动通信技术的优势,提出了将UHF通信技术运用于汽车分队指挥领域的设想,为进一步完善信息化指挥体系、推动汽车运输分队保障能力建设迈上新台阶提供技术支撑。     

Development of signal optimization models for asymmetric two-leg continuous flow intersections

Despite extensive studies have been reported to address the operational issues of full Continuous Flow Intersection (CFI) in the literature, the asymmetric two-leg CFI, which is more applicable in practice, has not received adequate attentions yet. To satisfy such need, this study develops two signal optimization models for asymmetric CFI based on its unique geometric features. The first proposed model, following a two-step procedure, determines the cycle length, phase design and sequence, and green split in the first step and optimizes intersection offset in the second step. To benefit both intersections’ capacity maximization and signal progression design by optimizing phase plan and sequence, the second proposed model takes the Mixed-Integer-Linear-Programming (MILP) technique to concurrently optimize all signal control variables. With extensive case studies on a field site in Maryland, the simulation results prove that the proposed models can effectively provide signal progression to critical path-flows and prevent the potential queue spillover on the short turning bays/links. Further comparisons between the two proposed models reveal that the second model is more flexible in designing phase plan but the first model performs better in reducing link queue length.     

斜置短波宽带鞭状近垂直入射天线原理

静区的存在是短波通信的重要特征之一，克服静区，实现战术通信是研究的主题。介绍了斜置短波宽带鞭状近垂直入射天线克服短波通信中的静区现象的原理及实现方法。     

宽窄带一体化综合接入设备

综合接入设备的出现从一定程度上缓解了网络带宽的压力.对综合接入设备和宽、窄带接入设备进行了对比和分析,说明了综合接入设备的特点.     

广东铁通宽带业务支撑系统建设探讨

对广东铁通宽带业务支撑系统现状进行介绍；并对一个业务系统在实践过程中所遇到的问题进行探讨；提出如何根据企业业务发展的实际情况，对业务系统进行调整和改造。     

基于弹性绳理论的自主车辆防碰撞的路径规划

基于人工势场的引导策略,通过建立包括车道边界和障碍车的道路危险势场,采用弹性绳模型实现了车辆在高速公路上的车道保持和紧急避障功能。为了保证车辆在高速情形下避障的安全性,在障碍车辆原有势场基础上,在障碍车辆的前后各增加一个引导势场,使车辆能够提前避障,从而避障过程更安全。再结合Carsim仿真,在车辆的路径跟随过程中观察主车的横摆角速度的变化来判断车辆的稳定性。对直道和弯道两种情形进行避障仿真对比分析,结果表明:在障碍车辆前后添加引导势场能提前避障,从而使避障过程更安全。     

一种螺旋桨模型噪声的试验研究

螺旋桨模型试验中,有时噪声谱中出现窄带噪声峰,有人认为这个峰是梢涡空泡噪声,是“看不见的梢涡空泡”引起的,但这种解释未经实验证明。本文用实验证实这种窄带噪声峰与桨叶梢部流动有关,无论梢涡空泡可见与否,都可能出现。