漂浮起吊的海上风电安装平台设计关注点

针对具有漂浮起吊作业功能的海上风电安装平台面临规范和法规适应性方面的新情况,对有漂浮起吊功能的海上风电安装平台设计时应特别考虑的一些技术问题及处理办法进行了梳理,以期望给业界提供有益参考和借鉴。     

铁路无线通信数字化技术与应用探讨

DMR技术是铁路无线通信数字化的一种新的选择,技术的变革带来了很多思考与挑战,要加快推进数字化进程,需要各方的共同努力。     

An experimental testbed for mobile offshore base control concepts

 The concept of a mobile offshore base (MOB) reflects the need to stage and support military and humanitarian operations anywhere in the world. A MOB is a self-propelled, modular, floating platform that can be assembled into lengths of up to 2 km, as required, to provide logistic support to US military operations where fixed bases are not available or adequate. It accommodates the take-off and landing of C17 aircraft, and can be used for storage, as well as to send resources quickly to shore. In most concepts, the structure is made of three to five modules, which have to perform long-term station-keeping in the presence of winds, waves, and currents. This is usually referred to as dynamic positioning (DP). In the MOB, the alignment is maintained through the use of thrusters, connectors, or a combination of both. In this paper, we consider the real-time control of scaled models of a MOB. The modules are built at the 1 : 150 scale, and are kept aligned by rotating thrusters under a hierarchical hybrid control scheme. This paper describes a physical testbed developed at the University of California, Berkeley, under a grant from the US Office of Naval Research, for the purpose of evaluating competing MOB control concepts. Received: June 4, 2002 / Accepted: October 30, 2002 Acknowledgments. This material is based on work supported by the MOB Program of the US Office of Naval Research under grant N00014-98-1-0744. The authors would like to thank the Link Foundation for its support. Many thanks go to Stephen Spry for his experimental work. The photographs are courtesy of Bill Stone, Gerald Stone, and Jay Sullivan of the PATH Publications staff. Address correspondence to: A.R. Girard (e-mail: anouck@eecs.berkeley.edu)     

Fleet F-77在货物链海运环节应用的探讨

在全球化经济日趋一体化的今天，一旦货物链中的某个环节发生故障将产生连锁反应，导致多个国家地区以至全球经济的重创。海运由于其特殊性在当今货物链中扮演着极其重要的角色，而海运系统又是货物链中的脆弱环节，如何保证海运环节的通畅是保证整个货物链不断的关键。本着上述观点，探讨了Inmarsat新近推出的FteetF-77在保障海运通畅、保证全球货物链不断方面的重要应用，希望新技术业务的推出能对全球经济发展起一定的作用。     

AERMOD for near-road pollutant dispersion: Evaluation of model performance with different emission source representations and low wind options

The performance of the regulatory dispersion model AERMOD in simulating vehicle-emitted pollutant concentrations near-roadway using area or volume source representation of emissions and with different low wind options was assessed using the SF₆ tracer data from the General Motors (GM) Sulfur Dispersion Experiment. At downwind receptor locations, AERMOD, using either area or volume source emissions, can reasonably predict the tracer concentrations near the surface (0.5 m) but the model performance decreases at higher elevations (3.5m and 9.5m above the surface). For upwind receptors, using an area source representation leads to significant under-predictions due to AERMOD’s lack of treatment of lateral plume meander, but using volume source representation leads to over-predictions of upwind concentrations regardless of the low wind options for plume meander. Among the three low wind options currently available in AERMOD, best model performance is obtained with low wind option 3, which treats plume meander with a higher minimal standard deviation of the horizontal crosswind component (σ_v,min = 0.3 m s⁻¹), eliminates upwind component of dispersion and uses an effective lateral dispersion parameter (σ_y) to replicate centerline concentration. The optional adjustment of the surface friction velocity in the meteorological preprocessor AERMET does not lead to obvious improvements in predicted near-road concentrations for this application.     

Study on the framework of hybrid collision warning system using loop detectors and vehicle information

Safety warning systems generally operate based on information from sensors attached to individual vehicles. Various types of data used for collision risk calculation can be categorized into two types, microscopic or macroscopic, depending on how the sensors collect the information of traffic state. Most collision warning systems use only either of these types of data, but they all have limitations imposed by the data, such as requirement of high installation cost and high market penetration rate of devices. In order to overcome these limits, we propose a collision warning system that utilizes the integrated information of macroscopic data and microscopic data, from loop detectors and smartphones respectively. The proposed system is evaluated by simulating a real vehicle trip based on the NGSIM data. We compare the results against collision warning systems based on macroscopic data from infrastructure and microscopic data from Vehicle-to-Vehicle information. The analysis of three systems shows two findings that (a) ICWS (Infrastructure-based Collision Warning System) is inadequate for immediate collision warning system and (b) VCWS (V2V communication based Collision Warning System) and HCWS (Hybrid Collision Warning System) produce collision warning at very similar timing, even with different behavior of individual drivers. Advantages of HCWS are that it can be directly applied to existing system with small additional cost, because data of loop detector are already available to be used in Korea and smartphones are widely spread. Also, the computation power distributed to each individual smartphone greatly increases the efficiency of the system by distributing the computation resources and load.     

城市轨道交通iAFC方案研究

移动支付、语音购票、刷脸过闸等技术是城市轨道交通AFC(自动售检票系统)未来发展的方向。本文针对城市轨道交通领域移动支付技术的发展和应用,结合徐州地铁iAFC(互联网售检票系统)建设方案,对iAFC系统架构、业务场景、接口设计等方面进行阐述,对类似新建或改造AFC项目提供借鉴。     

铁路隧道防灾救援移动监控系统研究

针对目前铁路隧道防灾救援监控系统设置在就近车站或工务段值班室的固定监控终端不能满足快速救援响应的问题,为提高铁路隧道灾害应急响应能力,提出一种铁路隧道防灾救援移动监控系统设计方案。结合数据云服务平台和移动技术,通过移动互联网将移动终端与路局铁路隧道防灾救援信息系统移动服务平台对接,实现铁路隧道防灾救援移动监控,满足铁路隧道防灾救援的实时移动应急响应需求。     

数字与模拟对讲系统的对比分析

无线电对讲系统具有其他通信系统不可替代的实际作用,因而具有重要的研究和应用价值。随着通信技术的进步,数字化对讲系统受到越来越广泛的关注。为此,针对ETSI数字对讲标准DMR和现有模拟对讲系统进行详细分析,阐述数字化对讲系统的优势和所面临的问题。     

无线局域网高效地址自动分配协议

在无线局域网(MANET-Mobile Ad Hoc Networks)中IP地址如何无冲突的分配一直是一个重要的论题。本文将使用聚集自动分配和有效地址选择给出一个高效的分配方案。无线局域网是由一系列平等的主机所构成,我们需要一个IP地址自动分配协议来对这些移动的主机进行控制,而在该协议制定中很好的考虑到这一特性。