Effectiveness of red light cameras on the right‐angle crash involvement of motorcycles

Red light cameras (RLCs) have been used to reduce right‐angle collisions at signalized intersections. However, the effect of RLCs on motorcycle crashes has not been well investigated. The objective of this study is to evaluate the effectiveness of RLCs on motorcycle safety in Singapore. This is done by comparing their exposure, proneness of at‐fault right‐angle crashes as well as the resulting right‐angle collisions at RLC with those at non‐RLC sites. Estimating the crash vulnerability from not‐at‐fault crash involvements, the study shows that with a RLC, the relative crash vulnerability (RCV) or crash‐involved exposure of motorcycles at right‐angle crashes is reduced. Furthermore, field investigation of motorcycle maneuvers reveal that at non‐RLC arms, motorcyclists usually queue beyond the stop line, facilitating an earlier discharge, and hence become more exposed to the conflicting stream. However at arms with a RLC, motorcyclists are more restrained to avoid activating the RLC and hence become less exposed to conflicting traffic during the initial period of the green. The study also shows that in right‐angle collisions, the proneness of at‐fault crashes of motorcycles is lowest among all vehicle types. Hence motorcycles are more likely to be victims than the responsible parties in right‐angle crashes. RLCs have also been found to be very effective in reducing at‐fault crash involvements of other vehicle types which may implicate exposed motorcycles in the conflicting stream. Taking all these into account, the presence of RLCs should significantly reduce the vulnerability of motorcycles at signalized intersections. Copyright © 2010 John Wiley & Sons, Ltd.     

企业应用软件开发安全体系的构建

针对企业应用软件设计与开发过程中所需考虑的安全性问题,构建一套企业内部适用的应用软件开发安全体系.通过剖析企业应用软件常见漏洞防护技术,依照应用软件开发生命周期流程,从设计安全、编码安全、过程管理安全等方面重新梳理、补充企业应用软件开发安全体系的框架.考虑体系框架下对应安全要求,为了方便指导应用软件设计人员、代码开发人...     

设置公交专用道道路的交通脆弱性分析

设置公交专用道将对城市道路交通状态产生重大影响。本文首次将脆弱性的概念引入交通系统，通过对其进行评价和系统扰动下的交通状态分析，构建了交通脆弱性评价指标体系，建立了交通脆弱性评估数学模型，并对模型进行应用，对道路的交通脆弱性进行了分级研究。     

Vulnerability analysis of global container shipping liner network based on main channel disruption

The Malacca Strait, the Suez Canal and the Panama Canal play an important role in the global container shipping. To study the impact of main channel interruption on the container shipping, we analysed statistical data on all routes operated by the top 100 global container liner companies and constructed a network model. We selected four topological metrics to measure the network’s connectivity and used the network weekly total shipping capacity and average shortest shipping time to measure the network’s transportation capacity and transportation time. The interruption of the main channel is simulated, and the changes in the metrics are analysed. The results indicated that the network’s vulnerability is sensitive to main channel interruption. If the Malacca Strait is interrupted, the network’s prosperity degree fall by almost half and the network’s transportation time increase by more than a quarter if the Suez Canal is interrupted. In addition, East Asian and European container liner shipping have more than 50% dependence on the Malacca Strait and the Suez Canal. Moreover, the container transport time between ports in East Asia, Europe, and North America and the rest of the world increases by an average of 4–9 days in the main channel interruption.     

集装箱航运网络拓扑特性研究

从复杂网络理论角度出发,验证了集装箱航运网络具备无标度和小世界特性,由集装箱航运网络节点度分布、度相关性以及度与介数相关性分析得到了度较大的节点对集装箱航运网络影响程度较大的结论.选择度较大节点作为优先攻击目标,随机生成节点序列作为出错目标,进而比较出错和攻击对集装箱航运网络聚集系数、平均距离和网络效率等重要网络特性的影响.通过分析发现集装箱航运网络具有较好的鲁棒性,同时也具有较大的脆弱性.     

桥梁地震易损性分析研究概述

论述了国内外桥梁地震易损性分析研究的概况,并对其主要分析方法进行了较为全面的论述和对比,包括经验统计法、规范校核法、Pushover分析方法等,评述了经验和理论易损性曲线的形成,同时指出了目前研究中存在的问题与发展前景。     

��·��ͨ����������о�

道路交通网络脆弱性是道路网络单元遭到突发事件攻击后在路网单元间相互作用以及外界持续影响下引起的路网整体损失的量度.道路交通网络脆弱性评估除了考虑路网内部单元间相互作用外还应考虑路网节点单元的恢复能力.本文在提出路网脆弱性的概念和分析模型的基础上,综合考虑路网结构、交通流运行状态、应急救援点设置等因素,以路网用户最终损失旅行时间为测度进行了路网脆弱性评估.通过一个简单的路网进行了实例分析,并从新建、改扩建道路、改变救援点设置等方面提出了改善的建议.     

��·��ͨ��������������о���״��չ��

道路交通网络脆弱性评估是当前路网研究中新的热点和难点问题,识别路网脆弱性并进行有效的管理是应对交通系统危机情况的重要课题,它引起了学者们的广泛关注,本文主要针对当前路网脆弱性评估研究进行梳理和展望. 首先对路网脆弱性的概念进行了归纳总结,讨论了不同学者对路网脆弱性概念的共识和分歧. 其次分析了路网脆弱性与路网可靠性之间的联系和区别. 然后对当前路网脆弱性的评估方法进行了分类分析,将路网脆弱性的评估方法分为基于特定场景评估法、基于特定战略评估法、基于仿真的评估方法和数学模型评估方法四大类. 最后指出了路网脆弱性未来的研究方向.     

河谷型城市公交网络脆弱性研究——以兰州市为例

应用复杂网络理论,以兰州市为例研究河谷型城市公交网络的脆弱性.首先, 根据L 空间模型构建城市公交站点网络,分析该网络静态拓扑特性.然后,基于随意攻击 和蓄意攻击两种攻击模式,建立城市公交网络脆弱性测度指标,并对两种攻击模式下公 交网络的脆弱性进行分析.研究结果表明,由于兰州市特殊的河谷型地形特征,在蓄意攻 击下的脆弱性远远强于其在随意攻击下的脆弱性.最后,结合公交网络脆弱性特征研究公 交网络核心站点选取策略.结果表明,基于度的核心站点选择更适合兰州市公交网络,这 为兰州市交通规划和交通网络优化决策提供理论依据.     

基于KDE的高烈度区典型简支梁桥地震易损性分析

为研究高烈度强震区各种墩高典型公路简支梁的抗震性能,以某8度地震区高速公路典型10～40 m墩高公路简支梁为研究对象,采用一种核密度估计(KDE)的桥梁易损性分析法开展不同墩高桥梁地震易损性分析。利用OpenSees软件建立各种典型墩高桥梁全桥有限元模型。考虑桥梁结构参数与地震动输入的不确定性,通过时程分析获得各墩高对应桥梁各构件的最大动力响应。运用核密度估计的桥梁地震易损性分析方法建立不同墩高公路桥梁的易损性曲线,对比研究不同墩高对桥梁各关键构件在地震作用下的易损性能及其差异性,研究8度和9度罕遇地震时各墩高桥梁关键构件在4种损伤状态下对应的地震易损性分布特征。研究结果表明：汶川地震作用下10～40 m墩高典型公路简支梁桥墩抗震性能良好,支座比桥墩更易损,随着桥梁墩高的增加,支座越容易发生地震损伤破坏,建议墩高超过40 m的桥梁采取减震耗能、限位措施,限制主梁发生过大位移,提高桥梁抗震性能。建立的地震易损性曲线可用于评估各种墩高典型公路简支梁桥梁的抗震性能,并为类似高烈度地震区公路简支梁桥抗震设计提供依据。