It is known that probability density functions and probability mass functions can usually be calculated quite easily by numerically inverting their transforms (Laplace transforms and generating functions, respectively) with the Fourier-series method, but other more general functions can be substantially more difficult to invert, because the aliasing and roundoff errors tend to be more difficult...

The Fourier Series (FS) and the Discrete Fourier Transform (DFT) should be thought of as playing similar roles for periodic signals in either continuous time (FS) or discrete time (DFT). Both analyze signals into amplitude, phases, and frequencies of complex exponentials; both synthesize signals by linearly combining complex exponentials with appropriate amplitude, phase, and frequency. Finally...

Abstract: We show how Cagniard de Hoop method can be used, first to obtain error estimates for the Perfectly Matched Layers in acoustics (PML), then to understand the instabilities of the PML when applied to aeroacousics. The principle of the methods consists in applying to the equations a Laplace transform in time and a Fourier transform in one space variable to obtain an ordinary differential...

in the present work, a hybrid of fourier transform and homotopy perturbation method is developed for solving the non-homogeneous partial differential equations with variable coefficients. the fourier transform is employed with combination of homotopy perturbation method (hpm), the so called fourier transform homotopy perturbation method (fthpm) to solve the partial differential equations. the c...

A dynamical two dimensional problem of generalized thermoelasticity has been considered to examine the stresses in an isotropic elastic slab. Laplace transform for time variable and exponential Fourier transform for space variable has been applied in the basic equations to form a vector-matrix differential equation which is then solved by eigenvalue approach. Finally numerical computations of t...

Two approaches resulting in two different generalizations of the space-time-fractional advection-diffusion equation are discussed. The Caputo time-fractional derivative and Riesz fractional Laplacian are used. The fundamental solutions to the corresponding Cauchy and source problems in the case of one spatial variable are studied using the Laplace transform with respect to time and the Fourier ...

The nonlinear oscillator problem has extensive applications. In this paper, we examined the modified homotopy perturbation method to obtain the solution of the problem and to reduce the computational efforts. For the accuracy purpose the Laplace transform and Pade approximation have also been used. We construct the deformation equations by two components of the homotopy series, then by means of...

This paper is devoted to bulk-mediated surface diffusion of a particle which can diffuse both on a flat surface and in the bulk layer above the surface. It is assumed that the particle is on the surface initially (at t = 0) and at time t, while in between it may escape from the surface and come back any number of times. We propose a new approach to the problem, which reduces its solution to tha...