This paper proposes a hybrid method based on the forward-backward method （FBM） and the reciprocity theorem （RT） for evaluating the scattering field from dielectric rough surface with a 2D target above it. Here, th...This paper proposes a hybrid method based on the forward-backward method （FBM） and the reciprocity theorem （RT） for evaluating the scattering field from dielectric rough surface with a 2D target above it. Here, the equivalent electric/magnetic current densities on the rough surface as well as the scattering field from it are numerically calculated by FBM, and the scattered field from the isolated target is obtained utilizing the method of moments （MOM）. Meanwhile, the rescattered coupling interactions between the target and the surface are evaluated employing the combination of FBM and RT. Our hybrid method is first validated by available MOM results. Then, the functional dependences of bistatic and monostatic scattering from the target above rough surface upon the target altitude, incident and scattering angles are numerically simulated and discussed. This study presents a numerical description for the scattering mechanism associated with rescattered coupling interactions between a target and an underlying randomly rough surface.展开更多
Magnetotelluric sounding method based on the difference of the rock’s resistivity is an exploration method about doing research in earth’s resistivity and phase using the native electromagnetic field. The paper adop...Magnetotelluric sounding method based on the difference of the rock’s resistivity is an exploration method about doing research in earth’s resistivity and phase using the native electromagnetic field. The paper adopts 2D finite element method as the magnetotelluric forward method and calculates the total field by primary field (also named background field) plus secondary field. We can?get more accurate forward result through the finite element method and we can get the result effected by the dense degree of grid slightly by the total field. But the method is not effective?enough when the model is divided into relative big grid. When the frequency changes, program solves relevant equation separately. According to the feature of the algorithm, we apply MPI parallel method in the algorithm. Every process solves relevant equation. The account of frequency?that a process needs to solve in parallel computation is less than the account that the process?needs to solve in serial algorithm. We can see that the forward result is the same with the serial algorithm and proves the correctness of algorithm. We do statistics about the efficiency of the parallel algorithm. When the account of processes is from 2 to 8, the speedup is from 1.63 to 2.64. It proves the effectiveness of the parallel algorithm.展开更多
为解决传统网络路由转发体系缺乏灵活性的问题,提出了OpenTDR开放式架构方案。该方案通过集成二维路由和软件定义网络(software defined network,SDN)技术,可在不同时间段实施不同的流量均衡和节能机制。实验结果表明,由一维升级至二维...为解决传统网络路由转发体系缺乏灵活性的问题,提出了OpenTDR开放式架构方案。该方案通过集成二维路由和软件定义网络(software defined network,SDN)技术,可在不同时间段实施不同的流量均衡和节能机制。实验结果表明,由一维升级至二维的路由转发方式,配合SDN的集中式网络规划,可明显增强网络(尤其是广域网)的流量调度与服务质量控制的灵活性,达到流量均衡与节约能耗的目的。另外,二维路由机制兼容传统路由,为基于传统网络的SDN改造提供了可行的过渡方案。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 60571058)the National Defense Foundation of China
文摘This paper proposes a hybrid method based on the forward-backward method （FBM） and the reciprocity theorem （RT） for evaluating the scattering field from dielectric rough surface with a 2D target above it. Here, the equivalent electric/magnetic current densities on the rough surface as well as the scattering field from it are numerically calculated by FBM, and the scattered field from the isolated target is obtained utilizing the method of moments （MOM）. Meanwhile, the rescattered coupling interactions between the target and the surface are evaluated employing the combination of FBM and RT. Our hybrid method is first validated by available MOM results. Then, the functional dependences of bistatic and monostatic scattering from the target above rough surface upon the target altitude, incident and scattering angles are numerically simulated and discussed. This study presents a numerical description for the scattering mechanism associated with rescattered coupling interactions between a target and an underlying randomly rough surface.
文摘Magnetotelluric sounding method based on the difference of the rock’s resistivity is an exploration method about doing research in earth’s resistivity and phase using the native electromagnetic field. The paper adopts 2D finite element method as the magnetotelluric forward method and calculates the total field by primary field (also named background field) plus secondary field. We can?get more accurate forward result through the finite element method and we can get the result effected by the dense degree of grid slightly by the total field. But the method is not effective?enough when the model is divided into relative big grid. When the frequency changes, program solves relevant equation separately. According to the feature of the algorithm, we apply MPI parallel method in the algorithm. Every process solves relevant equation. The account of frequency?that a process needs to solve in parallel computation is less than the account that the process?needs to solve in serial algorithm. We can see that the forward result is the same with the serial algorithm and proves the correctness of algorithm. We do statistics about the efficiency of the parallel algorithm. When the account of processes is from 2 to 8, the speedup is from 1.63 to 2.64. It proves the effectiveness of the parallel algorithm.
文摘为解决传统网络路由转发体系缺乏灵活性的问题,提出了OpenTDR开放式架构方案。该方案通过集成二维路由和软件定义网络(software defined network,SDN)技术,可在不同时间段实施不同的流量均衡和节能机制。实验结果表明,由一维升级至二维的路由转发方式,配合SDN的集中式网络规划,可明显增强网络(尤其是广域网)的流量调度与服务质量控制的灵活性,达到流量均衡与节约能耗的目的。另外,二维路由机制兼容传统路由,为基于传统网络的SDN改造提供了可行的过渡方案。
