Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damp...Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damping performance of WADC designed by the conventional method may deteriorate or even has no effect when signal transmission delay is beyond delay margin, an index that denotes delay endurance degree of power system. Therefore, a new design method for WADC under the condition of expected damping factor and required signal transmission delay is presented in this work. An improved delay margin with less conservatism is derived by adopting a new Lyapunov-Krasovskii function and more compact bounding technique on the derivative of Lyapunov-Krasovskii functional. The improved delay margin, which constructs the correlation of damping factor and signal transmission delay, can be used to design WADC. WADC designed by the proposed method can ensure that power system satisfies expected damping factor when WADC input signal is delayed within delay margin. Satisfactory test results demonstrate the effectiveness of the proposed method.展开更多
跨数据中心网络是处于不同地区的数据中心网络(Data Center Networks,DCNs)通过广域网(Wide-Area Network,WAN)连接组成的网络,分布式应用通常基于该网络为用户提供高质量的服务。DCNs和WAN的缓冲区大小、往返时延存在显著差异,这导致...跨数据中心网络是处于不同地区的数据中心网络(Data Center Networks,DCNs)通过广域网(Wide-Area Network,WAN)连接组成的网络,分布式应用通常基于该网络为用户提供高质量的服务。DCNs和WAN的缓冲区大小、往返时延存在显著差异,这导致现有的Cubic拥塞控制算法在跨数据中心网络场景下出现降速不准确、丢包率过高以及与其他拥塞控制算法兼容性差等问题。针对以上挑战,提出了一种通过匹配不同发送速率模式的改进Cubic算法Cubic+。具体地,Cubic+整合了网络中的时延、ECN(Explicit Congestion Notification)和丢包信号。当拥塞发生在浅缓冲交换机时,Cubic+会周期性地排空队列;当拥塞发生在深缓冲路由器时,Cubic+会快速减少堆积的数据包。基于大规模NS3仿真实验结果表明,在跨数据中心网络流量模型下,Cubic+与现有流行算法相比,平均流完成时间最多减少了20.77%,第99百分位流完成时间最多减少了15.88%,为跨数据中心网络提供了一种高吞吐的拥塞控制算法。展开更多
基于InSAR能获取高精度、高空间分辨率、连续的地表形变信息,地面沉降及高精度形变信息对保障城市公共安全有重要意义。本文利用PS-InSAR和广域地表形变快速提取算法,基于2012年6月至2024年6月武汉市域范围内1600 km 2 COSMO-Skyed影像...基于InSAR能获取高精度、高空间分辨率、连续的地表形变信息,地面沉降及高精度形变信息对保障城市公共安全有重要意义。本文利用PS-InSAR和广域地表形变快速提取算法,基于2012年6月至2024年6月武汉市域范围内1600 km 2 COSMO-Skyed影像和2018年1月至2024年6月武汉市、鄂州市、黄冈市和黄石市32177 km 2 Sentinel-1影像获取地表形变时空分布信息,并依据GNSS和水准测量数据进行形变精度评估。结果表明,COSMO和Sentinel-1数据形变速率均方根误差分别在2.3~5.8和2.99~6.29 mm/a;COSMO和Sentinel-1时序形变均方根误差分别为4.96和5.2 mm。同时,提取地铁沿线、地铁保护区、大跨度建筑和基坑等重要基础设施区域形变信息,并分析形变与工程段起止时间等的相关性。最后,利用Logistic形变预测模型,对武汉市、鄂州市、黄冈市和黄石市地表沉降进行未来两年内地表形变预测,每季度预测一期,共8期。展开更多
基金Project(51007042) supported by the National Natural Science Foundation of China
文摘Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damping performance of WADC designed by the conventional method may deteriorate or even has no effect when signal transmission delay is beyond delay margin, an index that denotes delay endurance degree of power system. Therefore, a new design method for WADC under the condition of expected damping factor and required signal transmission delay is presented in this work. An improved delay margin with less conservatism is derived by adopting a new Lyapunov-Krasovskii function and more compact bounding technique on the derivative of Lyapunov-Krasovskii functional. The improved delay margin, which constructs the correlation of damping factor and signal transmission delay, can be used to design WADC. WADC designed by the proposed method can ensure that power system satisfies expected damping factor when WADC input signal is delayed within delay margin. Satisfactory test results demonstrate the effectiveness of the proposed method.
文摘基于InSAR能获取高精度、高空间分辨率、连续的地表形变信息,地面沉降及高精度形变信息对保障城市公共安全有重要意义。本文利用PS-InSAR和广域地表形变快速提取算法,基于2012年6月至2024年6月武汉市域范围内1600 km 2 COSMO-Skyed影像和2018年1月至2024年6月武汉市、鄂州市、黄冈市和黄石市32177 km 2 Sentinel-1影像获取地表形变时空分布信息,并依据GNSS和水准测量数据进行形变精度评估。结果表明,COSMO和Sentinel-1数据形变速率均方根误差分别在2.3~5.8和2.99~6.29 mm/a;COSMO和Sentinel-1时序形变均方根误差分别为4.96和5.2 mm。同时,提取地铁沿线、地铁保护区、大跨度建筑和基坑等重要基础设施区域形变信息,并分析形变与工程段起止时间等的相关性。最后,利用Logistic形变预测模型,对武汉市、鄂州市、黄冈市和黄石市地表沉降进行未来两年内地表形变预测,每季度预测一期,共8期。
