Mike21软件桩群概化方法在高桩码头中的应用

码头前沿水域的横流过大容易导致船舶撞击码头或系船缆绳断裂,进而引发安全事故,因此研究码头前沿水域的流场状况对码头轴线合理选取和船舶的安全靠泊有着非常重要的意义。基于桩群概化方法,采用Mike21软件中的三角形网格水动力模块(FM模块)对曹妃甸矿石一期、矿石三期高桩码头附近的流场进行了数值模拟,并与现场实测流速、流向进行对比验证,确定了模型中的桩群影响参数。在此基础上,深入研究相邻高桩码头桩群阻力对周边海域的影响,并对码头前横流进行计算和分析。此方法实施简单、计算效率高,对大范围海域影响研究结果合理,对高桩码头前沿水域有关流速、流向的计算结果更加准确,对码头轴线合理选取和船舶安全靠泊有重要的参考意义。     

疏浚助推经济与城市可持续发展

回顾中外疏浚业发展史,尤其是中国近现代民族疏浚业起步、萧条、恢复、发展的艰辛历程。从城市产业支撑、城市空间发展、城市环境治理的角度,介绍现代疏浚业对社会经济和城市建设的巨大作用,阐述疏浚在城市可持续发展过程中肩负的重要使命——让城市更宜居、让环境更美好。     

FPSO单点系泊系统安装及回接技术

单点系泊系统作为浮式生产储油卸油装置（Floating Production Storage and Offloading,FPSO）的核心组成部分,需在FPSO进入安装现场之前完成安装,随后FPSO进入安装现场进行回接。以我国南海某具体工程项目为背景,全面、系统地介绍FPSO悬链腿单点系泊系统的安装及回接方法,并采用OrcaFlex分析软件对各个施工步骤进行相关的模拟分析。该单点系泊系统的整个安装过程可分为抓地锚安装、下段锚腿铺设、锚腿张紧、上段锚腿铺设、单点浮筒拖航及就位和锚系回接单点浮筒等6个阶段。     

Modeling the interactions between car and bicycle in heterogeneous traffic

In this paper, a new cellular automata model is proposed to simulate the car and bicycle heterogeneous traffic on urban road. To capture the complex interactions between these two types of vehicles, a novel occupancy rule is adopted in the proposed model to consider the variable lateral distances of mixed vehicular traffic. Based on massive simulations, microscopic fundamental diagrams under different bicycle densities are devised. With these, the bicycle's spilling behavior is then investigated and discussed. In order to reflect the interference of a bicycle on a car, the interference transformation from friction state to block state is modeled explicitly. Finally, different simulation results under different occupancy rules indicate that the constant and fixed occupancy rule adopted in the previous studies might lead to overestimation of car flux in the heterogeneous traffic flows with different bicycle densities. Copyright © 2013 John Wiley & Sons, Ltd.     

Innovative strategies for urban car-sharing systems and a simulator to assess their performance

In this paper, three innovative car-sharing systems for urban areas are proposed, based on fleets of individual intelligent vehicles with three service characteristics: instant access, open-ended reservations and one-way trips. These features provide high flexibility but create an uneven distribution of vehicles among stations. Therefore, relocation of vehicles must be performed. Three different system procedures are proposed: in the first system, relocations are performed by users; in the other two, vehicles relocate automatically, thanks to their automation. In the first two systems, vehicles are accessible only at stations, whereas in the third they are also accessible along roads. In order to provide transport managers with a tool to test systems in different realities, an object-oriented simulator is developed. The simulation provides outputs of system performance, in terms of user waiting times and system efficiency. The proposed systems are simulated for the city of Genoa, in Italy, and a comparative analysis is presented.     

Instantaneous communication throughputs of vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) formed by connected vehicles in a traffic stream could be applied to improve safety, mobility, and environmental impacts of a transportation system. In this paper, we present analytical models for the instantaneous communication throughputs of VANETs to measure the efficiency of information propagation under various traffic conditions at a time instant. In particular, we define broadcast and unicast communication throughputs by the wireless channel bandwith multiplied by the average probabilities that one vehicle is a successful receiver and sender in a VAENT, respectively. With a protocol communication model, we derive formulas to determine the probabilities for an equipped vehicle to be a successful broadcast receiver and a successful unicast receiver/sender, and obtain broadcast and unicast throughputs along discrete and continuous traffic streams. We further examine the impacts on communication throughputs of the transmission range and the interference range of dedicated short range communication devices as well as the market penetration rate of equipped vehicles and the percentage of senders. Finally, we investigate the influence of shock waves on communication throughputs.     

水泥稳定砂砾就地冷再生工艺及其节能环保意义

道路损坏后路基和路面材料的再生利用不仅能够节约大量宝贵的筑路材料,而且具有重要的环境保护意义。采用冷再生技术将原有旧路面材料以专用机械作业方式进行就地再生,并将其作为水泥稳定砂砾摊铺在原有道路上并作为新铺道路的基础是实现上述理念的成功尝试。     

基于城市文化生态下的交通系统规划设计思考

本文主要是通过分析城市不同功能的模块的内在属性,探究城市交通系统如何在适应城市文化生态系统的情况下,通过合理的规划设计,实现自身功能的最大化,其次详细的阐述了为何要将城市的文化生态系统融合于如今城市快速发展建设中融合,最后针对城市不同功能模块提出了相应有效的交通规划设计思路。     

甩挂运输半挂车电子标识技术研究

针对现阶段的道路运输远程监控体系中无法识别半挂车的身份与特征信息的问题,通过对甩挂运输企业、站(场)、整车生产企业进行广泛调研,文中提出了基于RFID无线射频技术的甩挂运输半挂车身份电子标识技术要求,分析了电子标识具体技术参数的限值范围,为规范甩挂运输半挂车身份电子标识的发展提供了技术支撑。     

天然气车辆推广应用政策措施研究

天然气车辆因其能源结构调整效益和节能减排效益,在道路运输行业应用日趋广泛。但同时,其后期应用过程中的问题也随之显现,为引导道路运输企业更加科学合理的应用天然气汽车,本文通过对当前天然气车辆应用现状的分析,总结应用过程中的问题,对天然气车辆开展成本效益分析,最终提出适合天然气车辆推广应用的政策建议。