Routing, modulation and spectrum allocation in elastic optical networks is a problem aiming at increasing the capacity of the network. Many algorithms such as shortest path algorithm can be used as the routing section...Routing, modulation and spectrum allocation in elastic optical networks is a problem aiming at increasing the capacity of the network. Many algorithms such as shortest path algorithm can be used as the routing section of this problem. The efficiency of these algorithms is partly based on how the cost of each link is defined. In this study, we considered several basic metrics in cost of network links and compared their effects on the network capacity. In particular, the static costs and the dynamic costs were evaluated and compared. For dynamic scenarios, compared to static scenarios, at least one additional factor, the usage of the links, was added. We further considered a new factor that is based on probability of accommodating the signal at a given time in any given link. The results show that, among them, the shortest path algorithm provides the least blocking probability when the cost is a combination of link length and the abovementioned possibility/usage of the link.展开更多
To utilizing the characteristic of radar cross section （RCS） of the low detectable aircraft, a special path planning algorithm to eluding radars by the variable RCS is presented. The algorithm first gives the RCS ch...To utilizing the characteristic of radar cross section （RCS） of the low detectable aircraft, a special path planning algorithm to eluding radars by the variable RCS is presented. The algorithm first gives the RCS changing model of low detectable aircraft, then establishes a threat model of a ground-based air defense system according to the relations between RCS and the radar range coverage. By the new cost functions of the flight path, which consider both factors of the survival probability and the distance of total route, this path planning method is simulated based on the Dijkstra algorithm, and the planned route meets the flight capacity constraints. Simulation results show that using the effective path planning algorithm, the low detectable aircraft can give full play to its own advantage of stealth to achieve the purpose of silent penetration.展开更多
针对复杂环境下无人机路径优化算法收敛精度低、全局搜索能力弱及易陷入局部最优解的问题,提出了一种改进混合蜣螂优化算法(SPM and osprey based hybrid dung beetle optimizer,SO-DBO)。使用混沌映射SPM初始化种群位置,提高算法搜索...针对复杂环境下无人机路径优化算法收敛精度低、全局搜索能力弱及易陷入局部最优解的问题,提出了一种改进混合蜣螂优化算法(SPM and osprey based hybrid dung beetle optimizer,SO-DBO)。使用混沌映射SPM初始化种群位置,提高算法搜索效率。在滚球蜣螂种群有障碍模式和无障碍模式中分别引入动态全局勘探策略和随机角度策略,提升算法精度和全局搜索能力。在觅食蜣螂位置更新引入自适应T分布策略,增强算法逃离局部最优能力。通过动态权重因子提高算法全局搜索能力并降低陷入局部最优解的风险。实验结果表明:相比原始蜣螂优化算法(dung beetle optimizer,DBO)和粒子群算法(particle swarm optimization,PSO),改进后的SO-DBO算法代价函数指标在简单环境下分别改善了9.68%、12.93%,在复杂环境下分别改善了13.34%、17.00%,有效提升了算法的收敛速度、精度和稳定性。展开更多
针对电动垂直起降机(electric vertical take-off and landing,eVTOL)在复杂城市低空空域运行中存在的场景适应性不足和多约束耦合建模不足等突出问题,提出了融合不同任务场景和多目标优化的通用三维eVTOL飞行路径规划方法。首先,提出...针对电动垂直起降机(electric vertical take-off and landing,eVTOL)在复杂城市低空空域运行中存在的场景适应性不足和多约束耦合建模不足等突出问题,提出了融合不同任务场景和多目标优化的通用三维eVTOL飞行路径规划方法。首先,提出一种优化的结构化空域规划架构具体方法,以平衡低空空域航空器运行安全和空域容量之间的矛盾,确保空域资源的高效利用;其次,基于多旋翼eVTOL飞行器的飞行动力学与空气动力学特性,建立准确的能耗评估模型以进一步优化飞行路径,从而通过构建标准大气模型和障碍区环境建模,综合优化路径能耗、路径长度、路径平滑和计算时间,形成了全面的综合代价评估函数;最后,基于改进粒子群算法,提出了适用于不同运行场景并能应对各种交通活动需求的三维通用路径规划算法。仿真验证表明:通用三维全局路径规划方法能够在多种复杂场景下,针对不同任务需求规划出安全可行绿色的飞行路径;相较于传统路径规划算法,该改进方法在典型城市场景中展现出更优的能耗效率和航程优化等性能;在极端紧急任务场景下可快速生成应急路径,计算效率提升显著。研究结果为城市空中交通系统设计提供了兼顾安全性与经济性的解决方案,其多场景适应特性有助于推动立体化交通网络建设,为低空经济产业链发展提供技术支撑。展开更多
文摘Routing, modulation and spectrum allocation in elastic optical networks is a problem aiming at increasing the capacity of the network. Many algorithms such as shortest path algorithm can be used as the routing section of this problem. The efficiency of these algorithms is partly based on how the cost of each link is defined. In this study, we considered several basic metrics in cost of network links and compared their effects on the network capacity. In particular, the static costs and the dynamic costs were evaluated and compared. For dynamic scenarios, compared to static scenarios, at least one additional factor, the usage of the links, was added. We further considered a new factor that is based on probability of accommodating the signal at a given time in any given link. The results show that, among them, the shortest path algorithm provides the least blocking probability when the cost is a combination of link length and the abovementioned possibility/usage of the link.
文摘To utilizing the characteristic of radar cross section （RCS） of the low detectable aircraft, a special path planning algorithm to eluding radars by the variable RCS is presented. The algorithm first gives the RCS changing model of low detectable aircraft, then establishes a threat model of a ground-based air defense system according to the relations between RCS and the radar range coverage. By the new cost functions of the flight path, which consider both factors of the survival probability and the distance of total route, this path planning method is simulated based on the Dijkstra algorithm, and the planned route meets the flight capacity constraints. Simulation results show that using the effective path planning algorithm, the low detectable aircraft can give full play to its own advantage of stealth to achieve the purpose of silent penetration.
文摘针对电动垂直起降机(electric vertical take-off and landing,eVTOL)在复杂城市低空空域运行中存在的场景适应性不足和多约束耦合建模不足等突出问题,提出了融合不同任务场景和多目标优化的通用三维eVTOL飞行路径规划方法。首先,提出一种优化的结构化空域规划架构具体方法,以平衡低空空域航空器运行安全和空域容量之间的矛盾,确保空域资源的高效利用;其次,基于多旋翼eVTOL飞行器的飞行动力学与空气动力学特性,建立准确的能耗评估模型以进一步优化飞行路径,从而通过构建标准大气模型和障碍区环境建模,综合优化路径能耗、路径长度、路径平滑和计算时间,形成了全面的综合代价评估函数;最后,基于改进粒子群算法,提出了适用于不同运行场景并能应对各种交通活动需求的三维通用路径规划算法。仿真验证表明:通用三维全局路径规划方法能够在多种复杂场景下,针对不同任务需求规划出安全可行绿色的飞行路径;相较于传统路径规划算法,该改进方法在典型城市场景中展现出更优的能耗效率和航程优化等性能;在极端紧急任务场景下可快速生成应急路径,计算效率提升显著。研究结果为城市空中交通系统设计提供了兼顾安全性与经济性的解决方案,其多场景适应特性有助于推动立体化交通网络建设,为低空经济产业链发展提供技术支撑。
