Target modeling and scattering function calculating are important prerequisites and groundwork for the synthetic aperture radar（SAR） imaging simulation.According to the difficult problems that normal methods cannot ...Target modeling and scattering function calculating are important prerequisites and groundwork for the synthetic aperture radar（SAR） imaging simulation.According to the difficult problems that normal methods cannot calculate the scattering function of electrically large object under the condition to wideband,an effective method of improved equivalent edge currents is presented and applied to SAR imaging simulation for the first time.This method improves calculating velocity and has relatively high precision.The concrete steps of applying the method are given.By way of the simulation experiment,the effectiveness of the method is verified.展开更多
A practical method of estimation for the internal-resistance of polymer electrolyte membrane fuel cell (PEMFC) stack was adopted based on radial basis function (RBF) neural networks. In the training process, k-means c...A practical method of estimation for the internal-resistance of polymer electrolyte membrane fuel cell (PEMFC) stack was adopted based on radial basis function (RBF) neural networks. In the training process, k-means clustering algorithm was applied to select the network centers of the input training data. Furthermore, an equivalent electrical-circuit model with this internal-resistance was developed for investigation on the stack. Finally using the neural networks model of the equivalent resistance in the PEMFC stack, the simulation results of the estimation of equivalent internal-resistance of PEMFC were presented. The results show that this electrical PEMFC model is effective and is suitable for the study of control scheme, fault detection and the engineering analysis of electrical circuits.展开更多
为了解决传统硬阈值方法在处理异常测站时难以应对模糊边界的问题,提出一种新方法,将构造运动和观测误差引起的测站异常均视为粗差,并利用隶属度函数构建IGGⅢ等价权函数,以减小异常测站的影响。新方法引入模糊集理论,是一种基于标准化...为了解决传统硬阈值方法在处理异常测站时难以应对模糊边界的问题,提出一种新方法,将构造运动和观测误差引起的测站异常均视为粗差,并利用隶属度函数构建IGGⅢ等价权函数,以减小异常测站的影响。新方法引入模糊集理论,是一种基于标准化残差属于粗差的模糊子集隶属度函数改进的IGGⅢ抗差估计方法(membership function IGGⅢ,MF-IGGⅢ)。首先,通过模糊统计确定标准化残差受粗差污染程度最大的模糊子集的隶属度函数;然后,依据这些隶属度函数值构建等价权函数,并进行选权迭代。模拟实验和对环渤海区域GNSS速度场的拟合分析结果表明,该方法在异常测站检测方面的表现优于假设检验法、均值漂移法和IGGⅢ法,显示出较强的异常测站识别能力。展开更多
基金supported by the National Natural Science Foundation of China(60871070)
文摘Target modeling and scattering function calculating are important prerequisites and groundwork for the synthetic aperture radar（SAR） imaging simulation.According to the difficult problems that normal methods cannot calculate the scattering function of electrically large object under the condition to wideband,an effective method of improved equivalent edge currents is presented and applied to SAR imaging simulation for the first time.This method improves calculating velocity and has relatively high precision.The concrete steps of applying the method are given.By way of the simulation experiment,the effectiveness of the method is verified.
基金Project (2003AA517020) supported by the National High-Tech Research and Development Program of China
文摘A practical method of estimation for the internal-resistance of polymer electrolyte membrane fuel cell (PEMFC) stack was adopted based on radial basis function (RBF) neural networks. In the training process, k-means clustering algorithm was applied to select the network centers of the input training data. Furthermore, an equivalent electrical-circuit model with this internal-resistance was developed for investigation on the stack. Finally using the neural networks model of the equivalent resistance in the PEMFC stack, the simulation results of the estimation of equivalent internal-resistance of PEMFC were presented. The results show that this electrical PEMFC model is effective and is suitable for the study of control scheme, fault detection and the engineering analysis of electrical circuits.
文摘为了解决传统硬阈值方法在处理异常测站时难以应对模糊边界的问题,提出一种新方法,将构造运动和观测误差引起的测站异常均视为粗差,并利用隶属度函数构建IGGⅢ等价权函数,以减小异常测站的影响。新方法引入模糊集理论,是一种基于标准化残差属于粗差的模糊子集隶属度函数改进的IGGⅢ抗差估计方法(membership function IGGⅢ,MF-IGGⅢ)。首先,通过模糊统计确定标准化残差受粗差污染程度最大的模糊子集的隶属度函数;然后,依据这些隶属度函数值构建等价权函数,并进行选权迭代。模拟实验和对环渤海区域GNSS速度场的拟合分析结果表明,该方法在异常测站检测方面的表现优于假设检验法、均值漂移法和IGGⅢ法,显示出较强的异常测站识别能力。
