共查询到20条相似文献，搜索用时 234 毫秒
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基于子空间分解的阵列信号处理技术可以突破瑞利限的约束,具有极高的角度分辨能力,但由于要作特征分解,需付出巨大的运算量代价.乘幂法是近代数值分析中快速得到矩阵特征值与特征向量的迭代算法,本文将两者有机结合,得到了一种快速求解信号子空间的迭代算法.仿真结果验证了该算法的有效性. 相似文献
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稀疏长时延水声信道的压缩感知估计(英文) 总被引：1，自引：0，他引：1
提出一种基于压缩感知框架下的长时延水声信道估计算法.用传统的自适应算法如最小二乘(LS)算法处理典型的长时延水声信道的估计问题时,会导致其收敛速率下降,即跟踪能力有限,而使用时延多普勒函数则加大了计算量和复杂度.通过训练序列构建一个Toeplitz矩阵作为测量矩阵,将长时延信道估计问题转为压缩感知问题,并利用信道的稀疏结构特性进行稀疏估计.与传统的l1范数或基于指数形式的近似l0范数稀疏恢复策略不同,所提出的是一种新的似l0范数稀算法(简称AL0),该算法通过融合最陡梯度和迭代投影寻优进行求解.仿真与海试数据结果验证了所提算法的优越性. 相似文献
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蔡静 《湖州师范学院学报》2007,29(2):123-125
为了寻求将实对称矩阵对角化的相似变换阵的有效方法,利用Householder变换给出了将实对称矩阵对角化的一种直接算法,还可在有限步内求出将实对称矩阵对角化的正交相似变换矩阵.在此基础上,可求得实对称矩阵的全部特征值和特征向量. 相似文献
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基于双窗口小波-Contourlet变换的图像融合算法 总被引：1，自引：0，他引：1
提出一种基于双窗口小波-Contourlet变换的图像融合算法.首先采用小波一Contourlet变换对图像进行分解,接着采用两种不同尺寸的窗口计算系数的特征值:低频子带采用区域能量法和高频子带采用区域方差法,分别比较双窗口下的高频子带和低频子带的系数特征值,比较的结果作为得到融合系数选择的依据,最后采用逆小波-Contourlet变换得到融合图像.仿真实验证实,在特征类型选择一致的情况下,该方法的融合性能优于小波变换法和Contourlet变换法,融合图像质量较好. 相似文献
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以双树复数小波基为稀疏基,局部哈达玛矩阵为观测矩阵,在IST算法的基础上提出一种改进的快度二步迭代混合范数算法,目标函数采用混合范数模型,二步迭代加速了目标函数的优化,二步迭代混合范数算法收敛于混合目标函数的最小值。改进的算法重构速度高于IST算法的2.5倍,图像的均方误差减小50%以上。与以DCT为稀疏基、高斯矩阵为观测矩阵、快速二步迭代混合范数算法为重构算法的压缩感知重构系统相比,改进算法的峰值信噪比提高了约1dB,表明改进算法具有更好的图像重构质量和重构速度。 相似文献
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《西安文理学院学报》2021,(2)
压缩感知理论突破了香农采样定律中对信号采样频率的限制.测量矩阵的构造是压缩感知理论中一个重要的部分.减小传感矩阵的互相干系数,选择性能较好的测量矩阵,能够提高重构质量.设计了EigGrd算法,Gram矩阵是由测量矩阵和稀疏变换矩阵乘积构成,使用特征值分解对Gram矩阵进行初始化,在稀疏变换矩阵固定的情况下,利用梯度下降法迭代优化传感矩阵,使得传感矩阵互不相干系数达到最大,从而优化了测量矩阵.在仿真实验中,将该方法与已知的测量矩阵比较,用优化的测量矩阵在图像重建中有着较高的峰值信噪比.表明了该方法优化的测量矩阵在图像重构精度上有着一定的优势. 相似文献
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姜亚琴 《常熟理工学院学报》2006,20(4):25-28,32
设A是m×n且秩为r的复矩阵,存在m×n次酉矩阵Q和n×n半正定矩阵H使得A=QH。此分解称为A的广义极分解。本文给出了在任意酉不变范数下次酉矩阵Q和半正定矩阵H的扰动界。 相似文献
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借助超几何函数的性质,结合Schur检验给出了复单位球上加权Berezin变换的Lp范数,推广了Liu和Zhou的关于复单位球上Berezin变换的Lp范数的结果. 相似文献
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在矩阵特征值分布理论和APA算法的基础上,给出了一种求非对称实矩阵特征值问题的并行NSM-APA算法,理论分析和在PVM下的数值结果表明,该算法比基于矩阵特征值分布理论的二分法收敛快,而且有较高的加速比. 相似文献
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卢鑫 《深圳信息职业技术学院学报》2007,5(2):10-13
在LTE(Long Term Evolution)的预编码技术中,预编码矩阵存在着使用酉阵和非酉阵的选择。本文分析了酉阵预编码的输出SINR的形式,提出了一种简化计算输出SINR计算的方法,计算4个矩阵(8个矢量)的输出SINR操作复杂度下降到原始方法的18%。同时分析了非酉阵预编码时的输出SINR相比于使用酉阵时的损失。仿真结果表明,非酉阵预编码相比于酉阵预编码在输出SINR上会有损失,这种损失从统计上可以用线性关系近似描述。 相似文献
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利用本文提出的迭代算法可得到矩阵AXB+CYD=E的双对称最小二乘解,并对算法的收敛性给出了证明,当选取初始矩阵为零时能得到矩阵方程的极小范数双对称最小二乘解,利用此方法还可得到任意给定矩阵的最佳逼近双对称解. 相似文献
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In this paper, based on an adaptive chaos synchronization scheme, two methods of encoding-decoding message for secure communication are proposed. With the first method, message is directly added to the chaotic signal with parameter uncertainty. In the second method, multi-parameter modulation is used to simultaneously transmit more than one digital message （i.e., the multichannel digital communication） through just a single signal, which switches among various chaotic attractors that differ only subtly. In theory, such a treatment increases the difficulty for the intruder to directly intercept the information, and meanwhile the implementation cost decreases significantly. In addition, numerical results show the methods are robust against weak noise, which implies their practicability. 相似文献
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In simultaneous matching-to-sample and oddity-from-sample tasks, briefly delaying the offset of trial stimuli following an incorrect choice response was found to facilitate task acquisition (Experiment 1). Because thispenalty-time procedure also resulted in longer choice-response latencies, it was hypothesized that any procedure that increased response latency would facilitate task acquisition. However, in Experiment 2, no evidence of facilitation was found when a 2-sec pause was imposed prior to the choice response. The results of Experiment 3 suggest that penalty-time facilitation of acquisition was not due to either the added differential outcome on correct versus incorrect trials (i.e., incorrect choice responses do not darken the keys as do correct choice responses) or the aversive effects associated with trial prolongation (i.e., incorrect responses not only result in the absence of reinforcement but also delay the start of the next trial). Instead, results suggest that birds trained with the penalty-time procedure review the trial stimuli following an incorrect choice. 相似文献
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Michael T. Kane 《Journal of Educational Measurement》1987,24(4):333-345
In judgmental standard setting procedures (e.g., the Angoff procedure), expert raters establish minimum pass levels (MPLs) for test items, and these MPLs are then combined to generate a passing score for the test. As suggested by Van der Linden (1982), item response theory (IRT) models may be useful in analyzing the results of judgmental standard setting studies. This paper examines three issues relevant to the use of lRT models in analyzing the results of such studies. First, a statistic for examining the fit of MPLs, based on judges' ratings, to an IRT model is suggested. Second, three methods for setting the passing score on a test based on item MPLs are analyzed; these analyses, based on theoretical models rather than empirical comparisons among the three methods, suggest that the traditional approach (i.e., setting the passing score on the test equal to the sum of the item MPLs) does not provide the best results. Third, a simple procedure, based on generalizability theory, for examining the sources of error in estimates of the passing score is discussed. 相似文献
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方琳 《南阳师范学院学报》2007,6(11):18-19
孟子的理想社会是依靠统治者实行仁政建立起来的:经济上关注民生,在此基础上建立人伦规范和对人民进行教化,在政治上得民心。这一思想对建设社会主义和谐社会具有重要启示。 相似文献
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Jee-Seon Kim 《Journal of Educational Measurement》2006,43(3):193-213
Simulation and real data studies are used to investigate the value of modeling multiple-choice distractors on item response theory linking. Using the characteristic curve linking procedure for Bock's (1972) nominal response model presented by Kim and Hanson (2002) , all-category linking (i.e., a linking based on all category characteristic curves of the linking items) is compared against correct-only (CO) linking (i.e., linking based on the correct category characteristic curves only) using a common-item nonequivalent groups design. The CO linking is shown to represent an approximation to what occurs when using a traditional correct/incorrect item response model for linking. Results suggest that the number of linking items needed to achieve an equivalent level of linking precision declines substantially when incorporating the distractor categories. 相似文献
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The current study examined special education teachers' ratings of the usefulness of strategy microanalytic assessment (SMA) (i.e., self‐regulation, strategy use) and standardized norm‐referenced assessment information (SNRA) (i.e., cognitive and academic skills). Ninety‐six participants separately rated the frequency with which SMA and SNRA are used in schools and the usefulness of each report [i.e., Teacher Rating Questionnaire (TRQ)] for intervention planning about a case study. A mixed model experimental design revealed that even though SNRA information is more typical of the data provided in evaluation reports/Individualized Educational Programs, the SMA data were rated significantly more helpful than the SNRA for enhancing important school‐related outcomes (e.g., test performance) as well as teacher‐related roles (e.g., developing instructional plans). Despite the participants' consistent preference for SMA information, their overall TRQ ratings of the SNRA were positive. © 2006 Wiley Periodicals, Inc. Psychol Schs 43: 149–155, 2006. 相似文献