Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and env...Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and environmental monitoring.Existing failure models primarily focus on power grids and traffic systems,and don't address the unique challenges of weak-communication UUSNs.In UUSNs,cascading failure present a complex and dynamic process driven by the coupling of unstable acoustic channels,passive node drift,adversarial attacks,and network heterogeneity.To address these challenges,a directed weighted graph model of UUSNs is first developed,in which node positions are updated according to ocean-current-driven drift and link weights reflect the probability of successful acoustic transmission.Building on this UUSNs graph model,a cascading failure model is proposed that integrates a normal-failure-recovery state-cycle mechanism,multiple attack strategies,and routingbased load redistribution.Finally,under a five-level connectivity UUSNs scheme,simulations are conducted to analyze how dynamic topology,network load,node recovery delay,and attack modes jointly affect network survivability.The main findings are:(1)moderate node drift can improve survivability by activating weak links;(2)based-energy routing(BER)outperform based-depth routing(BDR)in harsh conditions;(3)node self-recovery time is critical to network survivability;(4)traditional degree-based critical node metrics are inadequate for weak-communication UUSNs.These results provide a theoretical foundation for designing robust survivability mechanisms in weak-communication UUSNs.展开更多
黄螟Tetramoera schistaceana(Snellen)是甘蔗上的重要钻蛀性害虫。近年来,黄螟种群数量呈增长趋势,已跃升为广西蔗区的优势害虫种群。为明确影响黄螟自然种群发生发展的各项作用因子及其作用大小,2023年和2024年采用田间调查、室内饲...黄螟Tetramoera schistaceana(Snellen)是甘蔗上的重要钻蛀性害虫。近年来,黄螟种群数量呈增长趋势,已跃升为广西蔗区的优势害虫种群。为明确影响黄螟自然种群发生发展的各项作用因子及其作用大小,2023年和2024年采用田间调查、室内饲养观察以及桶栽甘蔗接虫试验相结合的方法,研究了甘蔗苗期黄螟各虫期种群数量变动规律与关键致死因子。构建黄螟自然种群生命表,运用种群数量排除作用控制指数(exclusion index of population control,EIPC)分析不同作用因子对黄螟种群数量的控制作用。结果表明,2023年和2024年黄螟自然种群趋势指数分别达到19.6425和19.3955,幼虫低龄期(1~3龄)的存活率均最低,是种群数量控制的关键期。在黄螟整个生长发育过程中,“捕食及病原菌”因素的种群控制效应最大,赤眼蜂作为卵期的优势天敌,对黄螟自然种群数量调控起关键作用。人工释放赤眼蜂后,2023年和2024年其对黄螟的排除作用控制指数比对照区分别提高1.0540和0.9632,控害效果显著。天敌赤眼蜂对黄螟种群数量有较为明显的控制作用。该结果为黄螟预测预报和综合防治提供坚实的理论基础。展开更多
基金supported in part by the National Natural Science Foundation of China(Key Program)under Grant No.62031021。
文摘Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and environmental monitoring.Existing failure models primarily focus on power grids and traffic systems,and don't address the unique challenges of weak-communication UUSNs.In UUSNs,cascading failure present a complex and dynamic process driven by the coupling of unstable acoustic channels,passive node drift,adversarial attacks,and network heterogeneity.To address these challenges,a directed weighted graph model of UUSNs is first developed,in which node positions are updated according to ocean-current-driven drift and link weights reflect the probability of successful acoustic transmission.Building on this UUSNs graph model,a cascading failure model is proposed that integrates a normal-failure-recovery state-cycle mechanism,multiple attack strategies,and routingbased load redistribution.Finally,under a five-level connectivity UUSNs scheme,simulations are conducted to analyze how dynamic topology,network load,node recovery delay,and attack modes jointly affect network survivability.The main findings are:(1)moderate node drift can improve survivability by activating weak links;(2)based-energy routing(BER)outperform based-depth routing(BDR)in harsh conditions;(3)node self-recovery time is critical to network survivability;(4)traditional degree-based critical node metrics are inadequate for weak-communication UUSNs.These results provide a theoretical foundation for designing robust survivability mechanisms in weak-communication UUSNs.
文摘黄螟Tetramoera schistaceana(Snellen)是甘蔗上的重要钻蛀性害虫。近年来,黄螟种群数量呈增长趋势,已跃升为广西蔗区的优势害虫种群。为明确影响黄螟自然种群发生发展的各项作用因子及其作用大小,2023年和2024年采用田间调查、室内饲养观察以及桶栽甘蔗接虫试验相结合的方法,研究了甘蔗苗期黄螟各虫期种群数量变动规律与关键致死因子。构建黄螟自然种群生命表,运用种群数量排除作用控制指数(exclusion index of population control,EIPC)分析不同作用因子对黄螟种群数量的控制作用。结果表明,2023年和2024年黄螟自然种群趋势指数分别达到19.6425和19.3955,幼虫低龄期(1~3龄)的存活率均最低,是种群数量控制的关键期。在黄螟整个生长发育过程中,“捕食及病原菌”因素的种群控制效应最大,赤眼蜂作为卵期的优势天敌,对黄螟自然种群数量调控起关键作用。人工释放赤眼蜂后,2023年和2024年其对黄螟的排除作用控制指数比对照区分别提高1.0540和0.9632,控害效果显著。天敌赤眼蜂对黄螟种群数量有较为明显的控制作用。该结果为黄螟预测预报和综合防治提供坚实的理论基础。
