The study projects a flexible and compact wearable pear-shaped Super High Frequency(SHF)antenna that can provide detailed location recognition and tracking applicable to defense beacon technology.This mini aperture wi...The study projects a flexible and compact wearable pear-shaped Super High Frequency(SHF)antenna that can provide detailed location recognition and tracking applicable to defense beacon technology.This mini aperture with electrical dimensions of 0.12λ_(0)×0.22λ_(0)×0.01λ_(0)attains a vast bandwidth over 3.1-34.5 GHz Super High Frequency(SHF)frequency band at S_(11)≤-10 dB,peak gain of 7.14 dBi and proportionately homogeneous radiation pattern.The fractional bandwidth(%BW)acquired is 168%that envelopes diversified frequency spectrum inclusive of X band specifically targeted to all kinds of defense and military operations.The proposed antenna can be worn on a soldier's uniform and hence the Specific Absorption Rate simulation is accomplished.The Peak SAR Value over 1 g of tissue is 1.48 W/kg and for 10 g of tissue is 0.27 W/kg well under the safety standards.The flexibility is proven by analyzing the full electromagnetic simulations for various bending conditions.Time response analysis is attained with its Fidelity Factor and Group Delay.Communication excellence is determined using Link Budget Analysis and it is seen that margin at 100 Mbps is 62 m and at 200 Mbps is 59 m.Prototype is fabricated along with experimental validation.All the results show harmony in shaping the antenna to provide critical situational awareness and data sharing capabilities required in defense beacon technology for location identification.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
为分析灯桩在风浪环境下的水动力特性,并根据其应力集中点给出优化方案。通过VOF(volume of fluid)方法求解了灯桩表面在风浪中的压力分布,以及压力造成形变。结果表明:灯桩应力集中位置在灯桩中间支柱的根部,最大位移位置在灯桩顶端;...为分析灯桩在风浪环境下的水动力特性,并根据其应力集中点给出优化方案。通过VOF(volume of fluid)方法求解了灯桩表面在风浪中的压力分布,以及压力造成形变。结果表明:灯桩应力集中位置在灯桩中间支柱的根部,最大位移位置在灯桩顶端;据此研究了两种优化方案,斜柱支撑方案应力集中在支柱的顶部,比优化前减小32.2%,最大变形量在中部底座处,比优化前减小40.1%;端部加强方案应力集中在底部,比优化前减小0.08%,最大变形发生在灯桩顶部,与优化前相比减小了23.1%。可见支柱斜撑的灯桩结构可以有效地减小结构受到的应力强度,分散了灯桩其他部分受到的风浪的冲击,是更好的结构优化方案。展开更多
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b...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
基金the Defense Institute of Advanced Technology,Pune(DIAT,Pune)IIT Delhi。
文摘The study projects a flexible and compact wearable pear-shaped Super High Frequency(SHF)antenna that can provide detailed location recognition and tracking applicable to defense beacon technology.This mini aperture with electrical dimensions of 0.12λ_(0)×0.22λ_(0)×0.01λ_(0)attains a vast bandwidth over 3.1-34.5 GHz Super High Frequency(SHF)frequency band at S_(11)≤-10 dB,peak gain of 7.14 dBi and proportionately homogeneous radiation pattern.The fractional bandwidth(%BW)acquired is 168%that envelopes diversified frequency spectrum inclusive of X band specifically targeted to all kinds of defense and military operations.The proposed antenna can be worn on a soldier's uniform and hence the Specific Absorption Rate simulation is accomplished.The Peak SAR Value over 1 g of tissue is 1.48 W/kg and for 10 g of tissue is 0.27 W/kg well under the safety standards.The flexibility is proven by analyzing the full electromagnetic simulations for various bending conditions.Time response analysis is attained with its Fidelity Factor and Group Delay.Communication excellence is determined using Link Budget Analysis and it is seen that margin at 100 Mbps is 62 m and at 200 Mbps is 59 m.Prototype is fabricated along with experimental validation.All the results show harmony in shaping the antenna to provide critical situational awareness and data sharing capabilities required in defense beacon technology for location identification.
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。
文摘为分析灯桩在风浪环境下的水动力特性,并根据其应力集中点给出优化方案。通过VOF(volume of fluid)方法求解了灯桩表面在风浪中的压力分布,以及压力造成形变。结果表明:灯桩应力集中位置在灯桩中间支柱的根部,最大位移位置在灯桩顶端;据此研究了两种优化方案,斜柱支撑方案应力集中在支柱的顶部,比优化前减小32.2%,最大变形量在中部底座处,比优化前减小40.1%;端部加强方案应力集中在底部,比优化前减小0.08%,最大变形发生在灯桩顶部,与优化前相比减小了23.1%。可见支柱斜撑的灯桩结构可以有效地减小结构受到的应力强度,分散了灯桩其他部分受到的风浪的冲击,是更好的结构优化方案。
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。
