排序方式: 共有37条查询结果,搜索用时 15 毫秒
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基于GPRS的GPS/DR车辆组合导航的研究 总被引:4,自引:0,他引:4
分析用GPRS网络传输车辆定位信息及其他车辆信息的优点,论述GPS/DR组合导航的原理,描述车载移动终端硬件结构,并且给出一种实现方法。基于GPRS的GPS/DR组合导航将成为车辆导航的主流。 相似文献
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本系统利用单片机ATmega128控制GSM模块TC35i以短消息的方式实现了对铁路货车通过桥梁、隧道装载超限的远程安全监控.系统由监控报警收发装置、侵限检测系统、车号识别系统和人机交互界面4个子系统组成.利用红外线光电传感器对超限货物列车进行超限检测,通过监控报警收发装置将报警信息与车号识别装置读取的侵限列车车号信息传送到上位机,由相关人员对此信息进行处理,对货运装载超限状况实行实时远程监控与检测.经过了多次试验,结果证明该系统准确可靠. 相似文献
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Hazard perception tests may not be transferable between different countries, due to differences in traffic culture and infrastructure. Therefore, different instruments might be necessary for assessing hazard perception in various countries. The aim of the current study was to develop the Lithuanian hazard perception test based on static traffic images and test its psychometric properties. Thirty-four experienced drivers participated in a pilot study, and 125 drivers with diverse driving experience took part in the main study. The final test contained 27 static traffic scenes and the participants were asked to respond if they saw a hazard or not. Results demonstrated that the test has satisfactory internal consistency and test-retest reliability. It differentiated between inexperienced and experienced drivers, and between those experienced drivers who had less than three or more than three crashes in their driving history. The test has sufficient psychometric properties for research; still further development is needed in order to apply it for individual testing and decisions about licence provision. 相似文献
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众所周知,多数圬工拱桥结构的破坏都是由于其下部基础的沉降、变位等原因引发的。但具体的基础变形量计算方法及其对上部结构的影响程度并没有被人们详细研究,这里对发生垮塌事故的北方地区某三跨乱石拱桥进行分析。根据现场勘测数据进行桥位处水文、冲刷计算,确定1#桥墩基础的沉降量及变形量,并借助MIDAS/CIVIL有限元计算软件模拟这种基础变位对上部主拱圈结构的影响程度,得出了导致该桥坍塌的根本原因。可为类似桥梁工程的养护管理及事故鉴定等提供思路和参考。 相似文献
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斜拉索面内随机参数振动分析 总被引:2,自引:2,他引:0
为探讨斜拉索面内承受端部轴向零均值高斯白噪声位移激励下的随机振动特性,推导了基于伊藤方程标准形的斜拉桥拉索平面内索端承受轴向随机位移激励下的随机参数振动微分方程。利用Falsone改进随机线性化法、一般随机线性化法及Mont carlo数值模拟法求解了拉索振动状态向量的二阶矩均方响应。研究表明:改进随机线性化法与Mont carlo数值模拟法结果吻合较好,一般随机线性化法降低了拉索的振动响应。拉索横向均方响应随着激励谱密度强度的增大而增大,随着拉索阻尼比及拉索初始索力的增大而减小。 相似文献
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基于通信的列车控制系统工程设计中需注意的几个问题 总被引:1,自引:0,他引:1
刘会明 《城市轨道交通研究》2006,9(5):48-50
根据上海轨道交通8号线的实践经验,对地铁基于通信的列车控制(CBTC)系统工程设计中需要注意的几个具体问题,如:辅助轨旁系统的选用、轨旁无线设备的安装方式、轨旁无线接入点设备的供电方案、骨干通信网的选择等进行了讨论,并给出了解决建议。 相似文献
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Formal analysis of authentication in 802.11i 总被引:1,自引:0,他引:1
Authentication is the basis of the security of IEEE 802.11i standard. The authentication process in 802.11i involves two important protocols: a 4-way handshake and a group key handshake. A formal analysis of authentication in 802.11i is given via a belief multisets formalism. The analysis shows that the 4-way handshake and the group key handshake may provide satisfactory mutual authentication, key management, and issue of a new group temporal key from an access point to a user device, under the guarantee of mutual possession of a confidential pairwise master key. The analysis also shows that there exists a denial of service attack in the 4-way handshake and some seeming redundancies are useful in the protocol implementation. 相似文献