A novel feature set for low-dimensional signal representation, designed for classification or clustering of non-stationary signals with complex variation in time and frequency, is presented. The feature representation of a signal is given by the first left and right singular vectors of its ambiguity spectrum matrix. If the ambiguity matrix is of low rank, most signal information in time directi...

This paper presents a novel approach for power system dynamic voltage stability analysis based on the multi-input multi-output (MIMO) transfer function. The MIMO system is defined taking into account the critical nodal voltages as outputs and possible control variables as the input. Based on the modal analysis and singular value analysis, the dynamic voltage stability analysis is carried out. T...

We use the singular value decomposition of the array response matrix, frequency by frequency, to image selectively the edges of extended reflectors in a homogeneous medium. We show with numerical simulations in an ultrasound regime, and analytically in the Fraunhofer diffraction regime, that information about the edges is contained in the singular vectors for singular values that are intermedia...

The BRST quantisation of the Drinfeld-Sokolov reduction applied to the case of A (1) 2 is explored to construct in an unified and systematic way the general singular vectors in W 3 and W (2) 3 Verma modules. The construction relies on the use of proper quantum analogues of the classical DS gauge fixing transformations. Furthermore the stability groups W (η) of the highest weights of the W-Verma...

Singular value decomposition is the key tool in the analysis and understanding of linear regularization methods in Hilbert spaces. Besides simplifying computations it allows to provide a good understanding of properties of the forward problem compared to the prior information introduced by the regularization methods. In the last decade nonlinear variational approaches such as ` or total variati...

We study the behavior of stochastic gradient descent applied to $\|Ax -b \|_2^2 \rightarrow \min$ for invertible $A \in \mathbb{R}^{n \times n}$. show that there is an explicit constant $c_{A}$ depending (mildly) on $A$ such $$ \mathbb{E} ~\left\| Ax_{k+1}-b\right\|^2_{2} \leq \left(1 + \frac{c_{A}}{\|A\|_F^2}\right) \left\|A x_k \right\|^2_{2} - \frac{2}{\|A\|_F^2} \left\|A^T A (x_k x)\right\|...

Randomized Kaczmarz is a simple iterative method for finding solutions of linear systems $Ax = b$. We point out that the arising sequence $(x_k)_{k=1}^{\infty}$ tends to converge solution $x...