In marine seismic surveys, weak signals can be overlaid by stronger or even random noise. Detecting these challenging, especially when they are close to each other partially overlapping. Several normalization methods have already been proposed, but often lead distortion. this paper, we show that the unwrapped instantaneous phase of associated analytical signal is an effective detection tool and validate it using synthetic real data examples. This approach does not require user-defined...

The processing of Chirp data is limited by the usual recording signal envelope, which enhances its immediate visibility but prevents applying methods based on wave equations. This normally not case for Boomer data. However, both systems are monochannel instruments, cannot estimate properly propagation velocity in rocks. In this paper, we present two theorems: first one links or source spectrum with an expected amplitude decay curve; second defines conditions deconvolution stability enveloped...

Abstract We consider the approximation of inverse square root regularly accretive operators in Hilbert spaces. The is rational type and comes from use Gauss–Legendre rule applied to a special integral formulation fractional power. derive sharp error estimates, based on numerical range, provide some experiments. For practical purposes, finite-dimensional case also considered. In this setting, convergence shown be exponential type. method tested for computation generic

Abstract This paper deals with the computation of Hankel transform by means sinc rule applied after a special exponential transformation. An error analysis, particularly suitable for meromorphic functions, together parameter selection strategy, is considered. A prototype algorithm automatic integration also presented.

This paper introduces a very fast method for the computation of resolvent fractional powers operators. The analysis is kept in continuous setting (potentially unbounded) self-adjoint positive operators Hilbert spaces. based on Gauss-Laguerre rule, exploiting particular integral representation resolvent. We provide sharp error estimates that can be used to priori select number nodes achieve prescribed tolerance.

In this work we develop the Gaussian quadrature rule for weight functions involving fractional powers, exponentials and Bessel of first kind. Besides computation based on use standard modified Chebyshev algorithm, here present a very stable algorithm preconditioning moment matrix. Numerical experiments are provided geophysical application is considered.

This paper deals with the estimation of quadrature error a Gaussian formula for weight functions involving fractional powers, exponentials and Bessel first kind. For this purpose, in work averaged generalized rules are employed, together tentative priori approximation error. The numerical examples confirm reliability these approaches.

This paper deals with the computation of Lerch transcendent by means Gauss-Laguerre formula. An a priori estimate quadrature error, that allows to compute number nodes necessary achieve an arbitrary precision, is derived. Exploiting properties rule and error estimate, truncated approach also considered. The algorithm used its Matlab implementation are reported. numerical examples confirm reliability this approach.

This paper deals with the error analysis of trapezoidal rule for computation Fourier type integrals, based on two double exponential transformations. The theory allows to construct algorithms in which steplength and number nodes can be a priori selected. is also used design an automatic integrator that employed without any knowledge function involved problem. Several numerical examples, confirm reliability this strategy, are reported.

We consider the approximation of inverse square root regularly accretive operators in Hilbert spaces. The is rational type and comes from use Gauss-Legendre rule applied to a special integral formulation problem. derive sharp error estimates, based on numerical range, provide some experiments. For practical purposes, finite dimensional case also considered. In this setting, convergence shown be exponential type.

This paper introduces a very fast method for the computation of resolvent fractional powers operators. The analysis is kept in continuous setting (potentially unbounded) self adjoint positive operators Hilbert spaces. based on Gauss-Laguerre rule, exploiting particular integral representation resolvent. We provide sharp error estimates that can be used to priori select number nodes achieve prescribed tolerance.

This paper deals with the solution of Maxwell's equations to model electromagnetic fields in case a layered earth. The integrals involved are approximated by means novel approach based on splitting reflection term. inverse problem, consisting computation unknown underground conductivity distribution from set modeled magnetic field components, is also considered. Two optimization algorithms applied, line- and global-search methods, new minimization presented. Several EM surveys ground surface...