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Kunio Tanabe 《Annals of the Institute of Statistical Mathematics》1985,37(1):189-203
Summary Global analyses are given to continuous analogues of the Levenberg-Marquardt methoddx/dt=−(J
t(x)J(x)+δI)−1Jt(x)g(x), and the Newton-Raphson-Ben-Israel methoddx/dt=−J
+(x)g(x), for solving an over- and under-determined systemg(x)=0 of nonlinear equations. The characteristics of both methods are compared. Erros in some literature which dealt with related
continous analogue methods are pointed out.
The Institute of Statistical Mathematics 相似文献
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针对欠定盲语音分离传统字典学习算法不能优化字典尺寸的问题,提出了一种尺度自适应同步码字优化(Scale Adaptive Simultaneous Codeword Optimization, SASimCO)算法。设计了一种迭代调整字典尺寸的自适应字典学习策略,将训练的字典用于语音盲分离中,以提高语音源信号的恢复性能。所提算法依据设计的候选矩阵,计算候选矩阵中的原子重要性,按照原子重要性准则对字典进行添加与删除原子操作,最后迭代训练得到一个稀疏表示误差最优的字典,用于语音源信号的恢复。使用SiSEC(Signal Separation Evaluation Campaign)数据集对所提算法进行的仿真实验表明,相较于传统字典学习算法,所提算法提高了1~3 dB语音源分离性能,证明了该算法的优势。 相似文献
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Siegfried M. Rump 《BIT Numerical Mathematics》1999,39(1):143-151
The condition number of a problem measures the sensitivity of the answer to small changes in the input, where small refers to some distance measure. A problem is called ill-conditioned if the condition number is large, and it is called ill-posed if the condition number is infinity. It is known that for many problems the (normwise) distance to the nearest ill-posed problem is proportional to the reciprocal of the condition number. Recently it has been shown that for linear systems and matrix inversion this is also true for componentwise distances. In this note we show that this is no longer true for least squares problems and other problems involving rectangular matrices. Problems are identified which are arbitrarily ill-conditioned (in a componentwise sense) whereas any componentwise relative perturbation less than 1 cannot produce an ill-posed problem. Bounds are given using additional information on the matrix. 相似文献
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In practical engineering applications, the vibration signals collected by sensors often contain outliers, resulting in the separation accuracy of source signals from the observed signals being seriously affected. The mixing matrix estimation is crucial to the underdetermined blind source separation (UBSS), determining the accuracy level of the source signals recovery. Therefore, a two-stage clustering method is proposed by combining hierarchical clustering and K-means to improve the reliability of the estimated mixing matrix in this paper. The proposed method is used to solve the two major problems in the K-means algorithm: the random selection of initial cluster centers and the sensitivity of the algorithm to outliers. Firstly, the observed signals are clustered by hierarchical clustering to get the cluster centers. Secondly, the cosine distance is used to eliminate the outliers deviating from cluster centers. Then, the initial cluster centers are obtained by calculating the mean value of each remaining cluster. Finally, the mixing matrix is estimated with the improved K-means, and the sources are recovered using the least square method. Simulation and the reciprocating compressor fault experiments demonstrate the effectiveness of the proposed method. 相似文献
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In recent literature, grossly underdetermined linear models have been developed for certain experimental techniques in respiratory physiology. Because physiologically sensible solutions of the models are reasonably assumed to be smooth, it is possible to recover such solutions using smoothed least-squares techniques. Bounds on the variability of smooth solutions satisfying the model can be generated using linear programming.The second author was supported in this work by New Zealand Medical Research Council Grant No. 81/65 to Dr. E. A. Harris, Greenlane Hospital, Auckland, New Zealand. The authors are indebted to Dr. Harris for his support and guidance in the physiological aspects of the work. 相似文献
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盲信号分离中,判断观测信号个数与实际信源个数的关系对于信号分离算法的选择和算法效果的评估非常重要,但目前还缺乏有效的方法对正定和欠定情况进行区分性检验.针对这一问题,本文提出两种检验方法.第一种方法通过分析整个数据序列ICA分解输出分量之间的独立性来实现.理论分析表明,欠定条件下ICA分解输出分量之间必然不具有独立性,而正定条件下,只要源信号满足独立的前提假设,ICA分解输出分量之间可以相互独立.第二种方法中,我们对数据序列不同位置添加等长时间窗,根据ICA分解基向量的稳定性来检验正定性.理论分析表明,正定条件下不同窗口数据ICA分解的基向量都收敛到混合阵的基向量上,而欠定条件下,分解得到的基向量随不同时窗内源信号分布的变化而改变.本文通过仿真实验,证明了这两种方法的可行性. 相似文献
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