On the network connectivity of platoon-based vehicular cyber-physical systems

In the past few years, vehicular ad hoc networking (VANET) has attracted significant attention and many fundamental issues have been investigated, such as network connectivity, medium access control (MAC) mechanism, routing protocol, and quality of service (QoS). Nevertheless, most related work has been based on simplified assumptions on the underlying vehicle traffic dynamics, which has a tight interaction with VANET in practice. In this paper, we try to investigate VANET performance from the vehicular cyber-physical system (VCPS) perspective. Specifically, we consider VANET connectivity of platoon-based VCPSs where all vehicles drive in platoon-based patterns, which facilitate better traffic performance as well as information services. We first propose a novel architecture for platoon-based VCPSs, then we derive the vehicle distribution under platoon-based driving patterns on a highway. Based on the results, we further investigate inter-platoon connectivity in a bi-directional highway scenario and evaluate the expected time of safety message delivery among platoons, taking into account the effects of system parameters, such as traffic flow, velocity, platoon size and transmission range. Extensive simulations are conducted which validate the accuracy of our analysis. This study will be helpful to understand the behavior of VCPSs, and will be helpful to improve vehicle platoon design and deployment.     

谈客滚船发生事故时的应急措施

客滚船发生事故时,采取合理的措施以减少人员伤亡和财产损失非常重要。文中针对客滚船的结构特征和常见事故的特点,分析事故原因,提出合理处置措施,以期更好地应对事故的发生。     

Public transportation development and traffic accident prevention in Indonesia

Traffic accidents have long been known as an iceberg for comprehending the discrepancies of traffic management and entire transportation systems. Figures detailing traffic accidents in Indonesia, as is the case in many other countries, show significantly high numbers and severity levels; these types of totals are also evident in Jakarta, the highest-populated city in the country. While the common consensus recognizes that traffic accidents are the results of three different factor types, namely, human factors, vehicle factors, and external factors (including road conditions), human factors have the strongest influence—and figures on a worldwide scale corroborate that assertion. We, however, try to pinpoint the issues of non-human factors in light of increasing traffic accidents in Indonesia, where motorbike accidents account for the majority of incidents. We then consider three important pillars of action: the development of public transportation, improvement of the road ratio, and traffic management measures.     

全球车载通信DSRC标准发展及应用

研究了新一代车车、车路之间通信标准协议,即专用短程通信(Dedicated Short Range Communications,DSRC)和车载环境下的无线接入协议。调研了欧洲、日本、美国和中国车载通信标准的最新发展情况,阐述了DSRC系统架构、技术原理以及通信标准,重点分析了DSRC物理层和MAC层关键技术,比较了IEEE 802.11和IEEE 802.11p异同点,最后展望了DSRC技术在汽车工业、汽车通信上的发展前景。本文全面深入讲述DSRC技术特点,为下一步我国制定车载通信发展战略提供参考依据。     

灰色马尔可夫模型在交通事故预测中的应用

采用传统灰色GM(1,1)模型预测道路交通事故这类随机性、波动性较大的数据,存在拟合较差、精度不足等问题。运用马尔可夫模型对预测结果进行优化,并建立灰色马尔可夫预测模型。将该模型应用于1998~2007年全国道路交通事故数据来预测2008年事故次数,结果表明采用该模型预测精度达到96.9%,明显优于单独使用GM(1,1)模型的预测结果。     

大连“7·16”事故海上清污工作的深度思考

为及时应对大规模海上溢油污染事故,有效控制和消除污染,最大限度地降低溢油污染事故对海洋环境造成的影响.在分析大连“7·16”事故海上清污工作全过程的基础上,深入研究此次清污工作的成功经验和存在的问题.在国家和地方层面上,从体制、机制、法规、资金、装备和人员等方面提出加强我国海域和内河水域溢油应急能力建设的建议,对完善我国溢油应急体系,提升海上溢油污染事故的防治能力具有重要意义.     

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水上交通事故人因可靠性,一方面在风险预防阶段会受到风险水平的影响;另一方面,在险情发展及应对过程中会存在与外部影响因素的相互作用.因此,为全面评价水上交通事故人因可靠性,从风险预防和险情应对这两个角度,提出了基于风险系数和置信度的人因可靠性的定量评价方法.首先,利用三角模糊数分别建立了各风险要素和风险系数的评价标准,并应用证据理论对这3个风险要素进行融合,获取了该险情的风险系数.其次,引用人因交互模型全面分析了人因可靠性的影响因素,建立了人因可靠性检查表,并利用置信度建立了各影响因素定量评价模型.最后,选取了一起典型沉船事故为案例定量评价了人因可靠性,结果表明,本文提出的方法可以更为全面地分析人因可靠性.     

汽车的电量平衡计算

随着汽车上用电器的增多,在汽车电气系统的设计中,整车电气系统的电量平衡必须进行计算。一些文献对电器电量平衡计算进行了论述,但大多使用一些前人的"经验参数"进行计算,而没有给出令人信服的、基于严密推理的计算方法。本文翔实、系统地给出了整车电气系统的电量平衡具体的计算公式和方法,并结合实例阐述了这些方法的应用。     

基于VB、Matlab的交通事故现场勘查摄影测量系统的开发与应用

发生交通事故后,如何快速、准确地记录事故现场,目前尚未得到妥善解决。将摄影测量理论应用于交通事故现场勘查,运用VB和Matlab编程软件开发了交通事故现场勘查测量管理系统,并模拟了事故现场,将实际的测量值与使用交通事故现场勘查测量管理系统所计算的理论值相比较,误差较小,表明该系统具有一定的实用性。