ARtract-We have presented techniques [ 11 [ 6 ] based on linear prediction (LP) and singular value decomposition (SVD) for accurate estimation of closely spaced frequencies of sinusoidal signals in noise. In this note we extend these techniques to estimate the parameters of exponentially damped sinusoidal signals in noise. The estimation procedure presented here makes use of "backward predictio...

‎we study dual integral equations which appear in formulation of the‎ ‎potential distribution of an electrified plate with mixed boundary‎ ‎conditions‎. ‎these equations will be converted to a system of‎ ‎singular integral equations with cauchy type kernels‎. ‎using‎ ‎chebyshev polynomials‎, ‎we propose a method to approximate the‎ ‎solution of cauchy type singular integral equation which will ...

We investigate singularities of a general plane section of the dual variety of a smooth projective variety, or more generally, the discriminant variety associated with a linear system of divisors on a smooth projective variety. We show that, in characteristic 3, singular points of E6-type take the place of ordinary cusps in characteristic 0.

Abstract In this paper, an augmentation preconditioner for asymmetric saddle point problems with singular (1,1) blocks is introduced on the base of the recent article by He and Huang [Two augmentation preconditioners for nonsymmetric and indefinite saddle point linear systems with singular (1, 1) blocks, Comput. Math. Appl., 62 (2011) 87-92]. We study the spectral characteristics of the precond...

For each 1 ≤ n ≤ 6 we present formulas for the number of n−nodal curves in an n−dimensional linear system on a smooth, projective surface. This yields in particular the numbers of rational curves in the system of hyperplane sections of a generic K3−surface imbedded in IP n by a complete system of curves of genus n as well as the number 17,601,000 of rational (singular) plane quintic curves in a...

In this paper, we develop a technique to compute the Weierstrass Gap Sequence at a given point, no matter if simple or singular, on a plane curve, with respect to any linear system V ⊆ H(C,OC (n)). This technique can be useful to construct examples of curves with Weierstrass points of given weight, or to look for conditions for a sequence to be a Weierstrass Gap Sequence. We use this technique ...

In this paper ill-posed linear inverse problems that arises in many applications is considered. The instability of special kind of these problems and it's relation to the kernel, is described. For finding a stable solution to these problems we need some kind of regularization that is presented. The results have been applied for a singular equation.

In this paper, we discuss semiconvergence of the alternating iterative methods for solving singular systems. The semiconvergence theories for the alternating methods are established when the coefficient matrix is a singular matrix. Furthermore, the corresponding comparison theorems are obtained. Keywords—Alternating iterative method; Semiconvergence; Singular matrix.

Let S be a smooth algebraic surface satisfying the following property: H(OS(C)) = 0 (i = 1, 2) for any irreducible and reduced curve C ⊂ S. The aim of this paper is to provide a characterization of special linear systems on S which are singular along a set of double points in general position. As an application, the dimension of such systems is evaluated in case S is an Abelian, an Enriques, a ...