车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性,这些特性为消息的传播带来挑战,路由机制是实现消息传递的关键因素;地理位置路由被广泛地应用于VANETS,要求节点周期广播bea...车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性,这些特性为消息的传播带来挑战,路由机制是实现消息传递的关键因素;地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息;然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能;为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control);在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数;仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。展开更多
On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both ...On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both theoretical interpreting and computer simulation, explains how to measure the wavefront slope difference between two sub apertures through the determination of image displacements on detector plane. It includes a fast and accurate digital algorithm for detecting wavefront disturbance, which is much suitable for realization in such electrical hardwares as digital signal processors.展开更多
车载自组织网(vehicular Ad hoc networks,VANETs)中的车辆通过周期交互beacon实现信息共享,从而提高交通安全,然而VANETs无线网络特性系统易遭受多类攻击,特别是对beacon的传输攻击,即干扰beacon的传输,其严重影响VANETs的安全性能。为...车载自组织网(vehicular Ad hoc networks,VANETs)中的车辆通过周期交互beacon实现信息共享,从而提高交通安全,然而VANETs无线网络特性系统易遭受多类攻击,特别是对beacon的传输攻击,即干扰beacon的传输,其严重影响VANETs的安全性能。为此,建立车队platooning模型,提出实时检测干扰beacon传输的攻击方案。该方案首先将节点beacon传输时间分为相互独立的时隙,并依据此时隙将车辆分为不同的群,使得群间的beacon彼此不碰撞,从而降低beacon被干扰的概率。最后,针对两类攻击类型进行仿真。仿真结果表明,提出的检测攻击方案具有良好的性能,初始检测时间小于150 ms,平均检测率不低于0.9。在两个干扰者的情况下,漏警率小于0.15,平均的虚警率小于0.2。展开更多
In order to solve the onboard recorder search problem, a new beacon system based on radio direction finding tech- nique, which indicates the orientation of the recorder, is designed. The system consists of phase-locke...In order to solve the onboard recorder search problem, a new beacon system based on radio direction finding tech- nique, which indicates the orientation of the recorder, is designed. The system consists of phase-locked loop （PLL）, micro- processor, global position system （GPS） module, power module and so on. The scene simulation verifies the feasibility and reliability of the system. This beacon system can be applied to the recorder search in many fields, and can effectively reduce the search scope and improve work efficiency.展开更多
文摘车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性,这些特性为消息的传播带来挑战,路由机制是实现消息传递的关键因素;地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息;然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能;为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control);在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数;仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。
文摘On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both theoretical interpreting and computer simulation, explains how to measure the wavefront slope difference between two sub apertures through the determination of image displacements on detector plane. It includes a fast and accurate digital algorithm for detecting wavefront disturbance, which is much suitable for realization in such electrical hardwares as digital signal processors.
文摘车载自组织网(vehicular Ad hoc networks,VANETs)中的车辆通过周期交互beacon实现信息共享,从而提高交通安全,然而VANETs无线网络特性系统易遭受多类攻击,特别是对beacon的传输攻击,即干扰beacon的传输,其严重影响VANETs的安全性能。为此,建立车队platooning模型,提出实时检测干扰beacon传输的攻击方案。该方案首先将节点beacon传输时间分为相互独立的时隙,并依据此时隙将车辆分为不同的群,使得群间的beacon彼此不碰撞,从而降低beacon被干扰的概率。最后,针对两类攻击类型进行仿真。仿真结果表明,提出的检测攻击方案具有良好的性能,初始检测时间小于150 ms,平均检测率不低于0.9。在两个干扰者的情况下,漏警率小于0.15,平均的虚警率小于0.2。
文摘In order to solve the onboard recorder search problem, a new beacon system based on radio direction finding tech- nique, which indicates the orientation of the recorder, is designed. The system consists of phase-locked loop （PLL）, micro- processor, global position system （GPS） module, power module and so on. The scene simulation verifies the feasibility and reliability of the system. This beacon system can be applied to the recorder search in many fields, and can effectively reduce the search scope and improve work efficiency.
