Modeling rear-end collisions including the role of driver's visibility and light truck vehicles using a nested logit structure

This paper presents an analysis of the effect of the geometric incompatibility of light truck vehicles (LTV)--light-duty trucks, vans, and sport utility vehicles--on drivers' visibility of other passenger cars involved in rear-end collisions. The geometric incompatibility arises from the fact that most LTVs ride higher and are wider than regular passenger cars. The objective of this paper is to explore the effect of the lead vehicle's size on the rear-end crash configuration. Four rear-end crash configurations are defined based on the type of the two involved vehicles (lead and following vehicles). Nested logit models were calibrated to estimate the probabilities of the four rear-end crash configurations as a function of driver's age, gender, vehicle type, vehicle maneuver, light conditions, driver's visibility and speed. Results showed that driver's visibility and inattention in the following (striker) vehicle have the largest effect on being involved in a rear-end collision of configuration CarTrk (a regular passenger car striking an LTV). Possibly, indicating a sight distance problem. A driver of a smaller car following an LTV, have a problem seeing the roadway beyond the LTV, and therefore would not be able to adjust his/her speed accordingly, increasing the probability of a rear-end collision. Also, the probability of a CarTrk rear-end crash increases in the case that the lead vehicle stops suddenly.     

平果含泥铝土矿的开采运输

平果铝土矿属国内外少有的堆积型铝土矿床，原矿石含泥量高、粘性大，实际生产过程中在生产运输方面出现过较多的问题，特别是对普通型矿用自卸运输车辆来说，矿石结底粘斗问题较为突出。文章主要介绍了平果铝土矿开采运输过程中存在问题的分析及处理对策，提出了运输设备大型化，解决矿石粘结问题，是提高矿石运输效率的有效途径。     

考虑锁相环影响的直流下垂控制电动汽车系统并网动态特性分析

随着新能源在电网中的渗透率不断增加,传统电力系统的惯性效应、阻尼水平以及同步能力都发生了改变,致使电网稳定运行能力下降.为此,基于静止同步发电机模型,建立了考虑锁相环影响的直流下垂控制两级式电动汽车(EV)系统的并网模型,揭示了EV系统惯性、阻尼以及同步特性的影响因素和影响规律,使得EV系统具备辅助电网稳定运行的能力....     

Development of lithium batteries for energy storage and EV applications

The results of the Japanese national project of R&D on large-size lithium rechargeable batteries by Lithium Battery Energy Storage Technology Research Association (LIBES), as of fiscal year (FY) 2000 are reviewed. Based on the results of 10 Wh-class cell development in Phase I, the program of Phase II aims at further improvement of the performance of large-size cells and battery modules, and the formulation of roadmaps toward worldwide dissemination of large-size lithium secondary batteries. In addition to the above R&D programs, a new target was presented particularly for the near-term practical application of several kWh-class battery modules in FY 1998.

For the large-size battery modules, two types of 2 and 3 kWh-class battery modules have been developed for stationary device and electric vehicle applications, respectively. The battery modules for both types have achieved most of the targets other than cycle life. Currently, further improvements in the cycle life of the cells themselves are being pursued. For this purpose, the materials for cathodes and anodes, the shapes and structures for batteries and the methods for cell connection are being re-investigated.

The development of middle-size battery systems for mini-size electric vehicles (EVs), as well as for demand-side stationary device applications is under way. These battery systems have been fabricated and their fundamental performance confirmed. They are now being subjected to field tests.     

BRDF模型及其反演研究的现状及展望

介绍了二向性反射的物理模型及半经验模型在理论研究中的新进展,并分析了各个模型的优缺点,为模型选择提供了依据;同时对模型反演的策略和方法及最新研究进展进行了概述。在此基础上,对实验研究、理论研究以及应用研究中存在的主要问题及目前的一些解决方案进行了分析,并讨论了遥感反演研究的未来发展方向。     

车用乙醇汽油及其消防对策

主要讨论了用车乙醇汽油的组成特性、火灾特点及相应的消防对策。     

Risk assessment of satellite launch with reusable launch vehicle

A new methodology is developed for assessing the risk associated with launching satellites in space by use of Reusable Launch Vehicles (RLVs). The objective is to assess the Maximum Probable Loss (MPL) for third party insurance purposes, which is a requirement for licensing of private operators. Launch industry convention has been to execute an MPL analysis for each and every flight. With the advent of commercial, reusable launch vehicle services, much higher flight rates are anticipated. Consequently a method for developing a conservative, ‘once-and-for-all’ MPL value is desirable. Failures during the boost, orbital vehicle, and return phases of the flight that could lead to impact of the rocket or its stages on the ground are considered. Simple geometric models are used to evaluate an upper bound to the probability that assets of various form and size on the ground will be hit by a stray rocket or vehicle stage. Models for the loss resulting from hitting an asset are also developed. The methodology is applied to a proposed launch site in Southern Australia.     

欠驱动水下机器人三维轨迹跟踪有限时间预设性能控制

本文研究了具有不确定动态和未知时变海洋环境扰动的欠驱动水下机器人(AUVs)三维轨迹跟踪有限时间预设性能控制问题,提出新型预设性能函数和误差映射函数,将受预设性能限制的轨迹跟踪误差转变为非受限的变换后误差;构造新的超螺旋(ST)扩张状态观测器,在有限时间内实时估计AUV不确定动态和未知时变海洋环境扰动引起的总扰动;基于...     

高速转向工况下的无人驾驶车辆路径跟踪

为提高无人驾驶车辆在高速转向工况下的路径跟踪精度与行驶稳定性,基于三自由度单轨车辆模型与模型预测控制理论,分析前轮转角约束对车辆跟踪精度与行驶稳定性的影响,提出一种自适应于侧向附着力的路径跟踪控制方法.以Pacejka'89魔术公式轮胎模型为基础,分析轮胎纵向受力,以此推算轮胎的侧向附着力,从而建立前轮转角约束随车辆状...     

选择性催化氧化除去甲醇燃料电池电动车上富氢气中CO的研究进展

评述了间接甲醇燃料电池电动车中存在的甲醇转化的富氢气中CO的净化技术 ,介绍了选择性氧化除去富氢气中CO的研究进展。