由于GPS/PWV资料在短时和临近天气预报、人工影响天气和空中水资源研究中具有潜在应用价值。考虑到GPS/PWV资料存在较多缺测,文中基于专家场模型(Fields of Experts,FoEs)进行了GPS/PWV资料插补初步研究。采用交叉验证法检验了常用插值...由于GPS/PWV资料在短时和临近天气预报、人工影响天气和空中水资源研究中具有潜在应用价值。考虑到GPS/PWV资料存在较多缺测,文中基于专家场模型(Fields of Experts,FoEs)进行了GPS/PWV资料插补初步研究。采用交叉验证法检验了常用插值方法(临近点、线性、三次样条和立方插值法)和FoEs插补GPS/PWV的精度,得到的FoEs模型插补精度较高。进一步给出了FoEs插补GPS/PWV连续缺测资料,解决了常用插值法无法对连续缺测资料有效插值的问题,为其它资料插补提供了新的思路。展开更多
本着提高安徽省地面气温资料质量的宗旨,文中采用模糊C均值(Fuzzy C-Means,FCM)聚类法进行地面气温资料的质量控制研究。具体执行过程中,通过FCM将区域内各测温划分为若干气温相似的聚类,定义离群率(空间尺度)和离群速度(时间尺度)识别...本着提高安徽省地面气温资料质量的宗旨,文中采用模糊C均值(Fuzzy C-Means,FCM)聚类法进行地面气温资料的质量控制研究。具体执行过程中,通过FCM将区域内各测温划分为若干气温相似的聚类,定义离群率(空间尺度)和离群速度(时间尺度)识别出气温资料中的离群值。进一步基于专家场模型(Fields of Experts,FoEs)对识别出的气温离群值进行订正,FoEs考虑了邻近站和本站前后时次的气温信息。与传统方法相比,文中算法从整体气温出发,不需要设置气温参考值,FoEs不仅能够订正离群资料,还能对连续缺测资料进行插补。因而文中的方法具有实用性和科学性,较适合计算大样本的气温数据集。展开更多
This research paper deals with the identification of the best location of the Power System Stabilizers (PSS) and also the tuning of PSS parameters in order to improve the overall dynamic stability of multi machine pow...This research paper deals with the identification of the best location of the Power System Stabilizers (PSS) and also the tuning of PSS parameters in order to improve the overall dynamic stability of multi machine power systems. The location of PSS is determined by identifying the critical modes and their corresponding first and second order eigenvalue sensitivities. In this formulation, sensitivity analysis of a particular mode can be performed with only its eigenvalues and their left and right eigenvectors. The simplicity and efficiency of this approach sharply contrast to the complexity of the traditional approach, where all eigenvalues and eigenvectors are required at the same time. The effectiveness of this method in selecting the optimum location for placement of PSSs is compared with the participation factor method. The proposed sensitivity theory used to identify the best PSS location in a five machine, eight bus El-Metwally and Malik System to increase the damping of both local and inter area modes for various operating conditions.展开更多
运动视差的关键点(Focus of Expansion,FOE)是铁路接触网视频巡检的重要参数,但当前计算FOE的方法需多帧图像匹配估计,时间复杂度高。针对单帧图像FOE估计问题,结合自监督学习思想,提出了一种融合自监督学习的单帧图像FOE估计算法。搭...运动视差的关键点(Focus of Expansion,FOE)是铁路接触网视频巡检的重要参数,但当前计算FOE的方法需多帧图像匹配估计,时间复杂度高。针对单帧图像FOE估计问题,结合自监督学习思想,提出了一种融合自监督学习的单帧图像FOE估计算法。搭建了全卷积网络F-VGG(Fully-VisualGeometryGroup)作为FOE的预测器,通过融合代理任务自动生成样本数据的训练标签,实现了端到端的单帧图像FOE估计。实验结果表明:该方法在FOE预测精度上平均提升13.45%,检测速度提升56.27%,适于实时应用。展开更多
在结构化场景的轨道交通中,车载视频观测因相机平移运动而呈现出图像内容以某点为中心向四周扩散的现象,该点被称为FOE(Focus of Expansion)。当前计算FOE的算法对噪声敏感且计算量大,不能准确地计算铁路场景中的FOE。鉴于此,文中提出...在结构化场景的轨道交通中,车载视频观测因相机平移运动而呈现出图像内容以某点为中心向四周扩散的现象,该点被称为FOE(Focus of Expansion)。当前计算FOE的算法对噪声敏感且计算量大,不能准确地计算铁路场景中的FOE。鉴于此,文中提出一种铁路视频序列的FOE估计方法。该方法首先利用金字塔光流法对检测的Harris角点进行跟踪和粗匹配,并在此基础上利用RANSAC算法进行精确的匹配,求得基础矩阵,然后提取图像中的极线束并计算FOE。实验结果表明,所提算法比Hough直线求得的FOE误差小,适于实时应用。展开更多
Contextualizing his Foe(1986) in the backdrop of South African post- apartheid, Coetzee manipulates multifarious postmodern narrative ploys to purloin, rewrite and widen the canon Robinson Crusoe. In plural demonstrat...Contextualizing his Foe(1986) in the backdrop of South African post- apartheid, Coetzee manipulates multifarious postmodern narrative ploys to purloin, rewrite and widen the canon Robinson Crusoe. In plural demonstrations of dualistic patterns, this novel emphatically unravels Coetzee's textual subversion of the traditional overarching"western logocentrism"or"metaphysics of presence"via catechizing and debilitating the orthodoxy of the white supremacy as well as the male superiority.This detailed analysis, giving a Derridean reading, purports to anatomize and deconstruct the binary oppositions of Self/ Other,White/Black, and Man/Woman among Cruso, Friday and Susan Barton, and reach Coetzee's veritable concerns: to dissolve the Imperialist hierarchy and hegemony, to waive racial enclosure, and to build a dialogue that open up a real respect and coexistence for both the centered and the marginalized.展开更多
The orthogonal frequency division multiplexing（OFDM） is currently used in long term evolution（LTE） system. The time offset estimation（TOE） and frequency offset estimation（FOE） of OFDM is essential in mobile co...The orthogonal frequency division multiplexing（OFDM） is currently used in long term evolution（LTE） system. The time offset estimation（TOE） and frequency offset estimation（FOE） of OFDM is essential in mobile communication base. According to the conventional cross correlation TOE and FOE algorithms, a new cross correlation computation was proposed to estimate the time offset and frequency offset for LTE uplink system, so that the time offset and frequency offset can be estimated simultaneously with low complexity. Compared with the conventional TOE and FOE algorithms, the simulation show that the proposed can reduce complexity and improve performance for FOE with good performance for TOE in additive white Gaussian noise（AWGN） and multipath channel.展开更多
文摘由于GPS/PWV资料在短时和临近天气预报、人工影响天气和空中水资源研究中具有潜在应用价值。考虑到GPS/PWV资料存在较多缺测,文中基于专家场模型(Fields of Experts,FoEs)进行了GPS/PWV资料插补初步研究。采用交叉验证法检验了常用插值方法(临近点、线性、三次样条和立方插值法)和FoEs插补GPS/PWV的精度,得到的FoEs模型插补精度较高。进一步给出了FoEs插补GPS/PWV连续缺测资料,解决了常用插值法无法对连续缺测资料有效插值的问题,为其它资料插补提供了新的思路。
文摘本着提高安徽省地面气温资料质量的宗旨,文中采用模糊C均值(Fuzzy C-Means,FCM)聚类法进行地面气温资料的质量控制研究。具体执行过程中,通过FCM将区域内各测温划分为若干气温相似的聚类,定义离群率(空间尺度)和离群速度(时间尺度)识别出气温资料中的离群值。进一步基于专家场模型(Fields of Experts,FoEs)对识别出的气温离群值进行订正,FoEs考虑了邻近站和本站前后时次的气温信息。与传统方法相比,文中算法从整体气温出发,不需要设置气温参考值,FoEs不仅能够订正离群资料,还能对连续缺测资料进行插补。因而文中的方法具有实用性和科学性,较适合计算大样本的气温数据集。
文摘This research paper deals with the identification of the best location of the Power System Stabilizers (PSS) and also the tuning of PSS parameters in order to improve the overall dynamic stability of multi machine power systems. The location of PSS is determined by identifying the critical modes and their corresponding first and second order eigenvalue sensitivities. In this formulation, sensitivity analysis of a particular mode can be performed with only its eigenvalues and their left and right eigenvectors. The simplicity and efficiency of this approach sharply contrast to the complexity of the traditional approach, where all eigenvalues and eigenvectors are required at the same time. The effectiveness of this method in selecting the optimum location for placement of PSSs is compared with the participation factor method. The proposed sensitivity theory used to identify the best PSS location in a five machine, eight bus El-Metwally and Malik System to increase the damping of both local and inter area modes for various operating conditions.
文摘运动视差的关键点(Focus of Expansion,FOE)是铁路接触网视频巡检的重要参数,但当前计算FOE的方法需多帧图像匹配估计,时间复杂度高。针对单帧图像FOE估计问题,结合自监督学习思想,提出了一种融合自监督学习的单帧图像FOE估计算法。搭建了全卷积网络F-VGG(Fully-VisualGeometryGroup)作为FOE的预测器,通过融合代理任务自动生成样本数据的训练标签,实现了端到端的单帧图像FOE估计。实验结果表明:该方法在FOE预测精度上平均提升13.45%,检测速度提升56.27%,适于实时应用。
文摘在结构化场景的轨道交通中,车载视频观测因相机平移运动而呈现出图像内容以某点为中心向四周扩散的现象,该点被称为FOE(Focus of Expansion)。当前计算FOE的算法对噪声敏感且计算量大,不能准确地计算铁路场景中的FOE。鉴于此,文中提出一种铁路视频序列的FOE估计方法。该方法首先利用金字塔光流法对检测的Harris角点进行跟踪和粗匹配,并在此基础上利用RANSAC算法进行精确的匹配,求得基础矩阵,然后提取图像中的极线束并计算FOE。实验结果表明,所提算法比Hough直线求得的FOE误差小,适于实时应用。
文摘Contextualizing his Foe(1986) in the backdrop of South African post- apartheid, Coetzee manipulates multifarious postmodern narrative ploys to purloin, rewrite and widen the canon Robinson Crusoe. In plural demonstrations of dualistic patterns, this novel emphatically unravels Coetzee's textual subversion of the traditional overarching"western logocentrism"or"metaphysics of presence"via catechizing and debilitating the orthodoxy of the white supremacy as well as the male superiority.This detailed analysis, giving a Derridean reading, purports to anatomize and deconstruct the binary oppositions of Self/ Other,White/Black, and Man/Woman among Cruso, Friday and Susan Barton, and reach Coetzee's veritable concerns: to dissolve the Imperialist hierarchy and hegemony, to waive racial enclosure, and to build a dialogue that open up a real respect and coexistence for both the centered and the marginalized.
基金supported by the National Natural Science Foundation of China (60572117)the Scientific Research Foundation for the returned Overseas Chinese scholars, State Education Ministry
文摘The orthogonal frequency division multiplexing（OFDM） is currently used in long term evolution（LTE） system. The time offset estimation（TOE） and frequency offset estimation（FOE） of OFDM is essential in mobile communication base. According to the conventional cross correlation TOE and FOE algorithms, a new cross correlation computation was proposed to estimate the time offset and frequency offset for LTE uplink system, so that the time offset and frequency offset can be estimated simultaneously with low complexity. Compared with the conventional TOE and FOE algorithms, the simulation show that the proposed can reduce complexity and improve performance for FOE with good performance for TOE in additive white Gaussian noise（AWGN） and multipath channel.
