For a germ of analytic vector fields, the existence of first integrals, resonance and the convergence of normalization transforming the vector field to a normal form are closely related. In this paper we first provide a link between the number of first integrals and the resonant relations for a quasi-periodic vector field, which generalizes one of the Poincaré’s classical results [18] on autono...

We use linear and quasi-linear perturbation theory to analyse cold dark matter models of structure formation in spatially flat models with a cosmological constant. Both a tilted spectrum of density perturbations and a significant gravitational wave contribution to the microwave anisotropy are allowed as possibilities. We provide normalizations of the models to microwave anisotropies, as given b...

In speech recognition studies, vocal tract length normalization (VTLN) techniques are widely used to cancel ageand genderdifference. In VTLN, the distortion is often modeled as a linear transform in a cepstrum space; ĉ=Ac. In our previous study, the geometrical properties ofA were discussed and it was shown that the matrix can be approximated as rotation matrix. In this study, a new method of b...

In this paper we present an iterative inversion (II) approach to blind source separation (BSS). It consists of a quasi-Newton method for the resolution of an estimating equation obtained from the implicit inversion of a robust estimate of the mixing system. The resulting learning rule includes several existing algorithms for BSS as particular cases giving them a novel and unified interpretation...

To solve the low-frequency breakdown inherent from the electric field integral equation (EFIE), an alternative new form of the EFIE is proposed by using the Coulomb-gauge Green’s function of quasi-static approximation. Different from the commonly adopted Lorentz-gauge EFIE, the Coulomb-gauge EFIE separates the solenoidal and irrotational surface currents explicitly, which captures inductive and...

We study a basic algorithmic problem in algebraic geometry, which we call NNL, of constructing a normalizing map as per Noether’s Normalization Lemma. For general explicit varieties, as formally defined in this paper, we give a randomized polynomial-time Monte Carlo algorithm for this problem. For some interesting cases of explicit varieties, we give deterministic quasi-polynomial time algorith...

EXAFS studies on dilute samples are usually carried out by collecting the fluorescence yield using a large-area multi-element detector. This method is susceptible to the 'glitches' produced by all single-crystal monochromators. Glitches are sharp dips or spikes in the diffracted intensity at specific crystal orientations. If incorrectly compensated, they degrade the spectroscopic data. Normaliz...

This paper describes a method to compensate for spatial distortion in quasi-periodic structures allowing a noise reduction by averaging. The successive steps of processing are preprocessing by local normalization, the detection of control points by cross-correlation, the estimation and compensation of the warping function using bidimensional polynomials, and finally noise reduction by filtering...