主动悬架系统对汽车侧翻稳定性改善分析

针对被动悬架系统侧翻稳定性比较差的问题,提出采用主动悬架系统的方法进行改善。通过汽车侧倾运动状态分析,建立了被动悬架系统、主动悬架系统和控制系统模型。模拟分析得到主动悬架系统使得汽车在弯道行驶时的侧倾角有效值下降了92.8%,侧倾角加速度有效值下降了78.2%,侧翻因子有效值下降了92.6%。结果表明:利用主动悬架系统可以有效地降低汽车非直线行驶时的侧倾角以及侧倾角加速度,提高汽车的侧翻稳定性,是提高汽车非直线行驶状态下安全性的一个合理的解决方案。     

复杂路况下汽车主动避撞报警技术研究

汽车主动避撞报警技术对提高行车安全有重要意义,但如何减少复杂路况下行车时的误警率是当前需解决的关键问题。通过测量车载信息如汽车转向角度、车速、制动信号、转向灯信号等获知汽车的行驶状态,利用雷达技术感知路况和危险,基于合理的报警算法和控制策略,研制出复杂路况下的汽车主动避撞报警系统。通过实际道路报警试验,结果表明所采取的减少误警率的方法是有效的,所开发的报警系统更趋实用化。     

基于自适应遗传算法的路堤边坡稳定性分析方法

基于圆弧滑动面假定,提出了一种用自适应遗传算法搜索最危险滑动面及其对应的最小安全系数的新方法。该方法是一种改进的遗传算法,采用自适应求取适值、动态调整交叉率和变异率、自适应区间收缩。自适应遗传算法有效克服了传统方法易陷入局部极小的缺陷,提高了算法的搜索效率、精度和稳定性。     

南京长江二桥斜拉桥施工过程稳定性分析

针对南京二桥南汊钢斜拉桥,考虑结构的非线性和构件的极限承载能力,计入施工过程的变形和应力的叠加效应,用包含梁和索单元的空间组合结构模型,进行了大桥的结构行为分析,着重研究了在施工全过程中的结构稳定性问题。     

车辆高速行驶安全的思考

分析了轮胎等汽车部件对行车安全的作用，论述了对ABS和车轮定位参数日常检测的必要性．介绍了电涡流中央制动器的制动原理和使用成本。     

电动汽车充电桩安全管理研究

随着国家对环境保护和能源节约的重视以及新能源政策的实施,电动汽车行业迎来了快速发展。充电基础设施的建设,是加快电动汽车推广的重要需要。电动汽车充电基础设施建设和运营业务发展的机会也极大,随之而来的安全管理工作要求也越来越高。本文依据充电桩建设和运营的特点,剖析其中面临的安全风险,并提出加强安全管理工作的措施,为充电桩企业安全管理运营提供参考和借鉴。     

Urban walkability considering pedestrians’ perceptions of the built environment: a 10-year review and a case study in a medium-sized city in Latin America

ABSTRACT

Numerous methodologies measuring walkability have been developed over the last years. This paper reviews the Walkability Index (WI) literature of the last decade (2009–2018) and highlights some limitations in the current approaches. Only a few studies have evaluated walkability in Latin America, mainly in big cities but not in medium and small-sized cities in the region, which present their own urbanisation dynamics, security issues, sidewalk invasion problems, and poor planning. Furthermore, most WIs in the literature use objective mesoscale variables to assess walkability in a given area. This paper contributes to filling these gaps by generating new evidence from a medium-sized city in Latin America to question if characteristics of the built environment encourage walking trips, as found in the literature, are transferable among regions. The study also proposes a novel index comprised of microscale and mesoscale built environment variables to assess walkability using virtual tools and considering users’ perceptions. The WI estimation relies on ranking probability models. The results of the case study suggest that subjective Security and Traffic Safety are the most crucial factors influencing walkability in these kind of cities, which is different from what is found in the literature from cities in developed countries where Sidewalk Condition and Attractiveness are the most important factors. Security appeared to be strongly associated with a subjective dimension, represented by the fear of crime or perceived risk for crime, instead of the actual occurrence of crimes. This result evidences the importance of the physical attributes of the real world and how they are captured, judged, and processed by pedestrians. Then, regional transferability of WIs needs to be done carefully. Finally, results in this paper highlight the importance of microscale built environment characteristics in the WI formulation in these cities. Results are in line with other research in some cities of the region, which found that microscale variables such as pavement quality and presence of obstacles on the sidewalks are relevant components to promote walkability.     

航母飞行作业空间安全布局研究

研究针对航空母舰飞行作业空间安全问题而开展。研究首先根据作业特点划分航母作业区域，针对飞行作业分析构成空间危害因素的来源，提出一套度量危险因素的空间关联安全水平指标，以便对危险因素的空间关系进行量化；然后在此基础上，对2套不同起飞作业布局进行安全评价；最后，并围绕航母飞行甲板作业空间安全的典型问题进行分析和讨论。     

Theory of safety surrogates using vehicle trajectories in macroscopic and microscopic settings: Application to dynamic message signs controlled traffic at work zones

This paper presents a new mathematical framework for obtaining quantitative safety measure using macroscopic as well as microscopic traffic data. The safety surrogate obtained from the macroscopic data is in terms of analysis performed on vehicle trajectories obtained from the macroscopic data. This method of obtaining safety measure can be used for many different types of applications. The safety surrogate for the traffic dynamics are developed in terms of a new concept of Negative Speed Differentials (NSD) that involve a convolution of vehicle speed function obtained from vehicle trajectories and then performing the integration of the square of the output for its negative values. The framework is applicable to microscopic traffic dynamics as well where we can use car following models for microscopic dynamics or the LWR model for macroscopic dynamics. This paper then presents the use of this new safety surrogate on the development of a feedback control law for controlling traffic in work zones using Dynamic Message Signs. A hybrid dynamics model is used to represent the switching dynamics due to changing DMS messages. A feedback control design for choosing those messages is presented as well as a simple simulation example to show its application.     

Studies on emergency evacuation management for maritime transportation

Marine transportation is a vital component of the world’s economy and transportation network. The number of people using passenger ships around the globe is increasing worldwide. Similar to other transportation systems, passenger safety is critical in maritime shipment. As emergency evacuation processes for ships are highly different from and more complicated than those for buildings and other vehicles, many researchers have published a vast range of documents related to this peculiar research area. However, there is a tangible lack of sufficient literature review studies that investigate marine emergency evacuation (MEE). That being the case, the potential of marine transportation and the effect of emergency evacuation operation on life safety have inspired the proposal of this study. This paper offers a review of the available literature on MEE modelling, analysis and planning during the period from 1973 to 2017 using a systematic approach. After reviewing relevant academic journals, peer-reviewed conference papers, and technical reports of agencies, relevant literature is analysed. In addition, the literature review is extended by means of proposing a framework methodology which considers different possible conditions and situations during MEE. Finally, insights for ship managers and policymakers are discussed and potential future research directions are identified.