T h e Hapke bidirectional reflectance model has been widely used for soil modeling, but gives significant errors when the soil scatters very strongly and anisotropically. In our new model, we decompose the radiation field into three components instead of two: single-scattering radiance, double-scattering radiance, and multiple-scattering radiance. The first two components can be exactly calcula...

A nonlinear optimization method is proposed for the solution of inverse scattering problems in the frequency domain, when the scattered field is governed by the Helmholtz equation. The time-harmonic inverse medium problem is formulated as a PDE-constrained optimization problem and solved by an inexact truncated Newtontype iteration. Instead of a grid-based discrete representation, the unknown w...

Packet switching networks lead mostly to M/GI/1 queue models. In this paper, computing methods are designed in order to get quickly approximate values for response time of these networks. Laplace transform is a powerful tool to study such queuing systems. But inversion of the Laplace transform on the real line is well known to be an illconditioned problem and usual numerical methods of inversio...

The paper presents an innovative way of a simulation of multiconductor transmission line (MTL) circuits which combines the Laplace transformations in one and in two variables. This approach enables to compute both nodal voltages (branch currents) in lumped-element parts of a circuit and voltage (current) waves distributions along MTLs’ wires effectively. The first one is performed by the numeri...

We describe regularized methods for image reconstruction and focus on the question of hyperparameter and instrument parameter estimation, i.e. unsupervised and myopic problems. We developed a Bayesian framework that is based on the posterior density for all unknown quantities, given the observations. This density is explored by a Markov Chain Monte-Carlo sampling technique based on a Gibbs loop...

In this abstract, we present a case study in the application of a time-stepping method, unconstrained by the CFL condition, for computational acoustic wave propagation in the context of full waveform inversion. The numerical scheme is a locally one-dimensional (LOD) variant of alternating dimension implicit (ADI) method. The LOD method has a maximum time step that is restricted only by the Nyqu...

The paper deals with a technique of sensitivity calculation in linear hybrid networks containing elements with both lumped and distributed parameters when the multiconductor transmission lines (MTL) are considered as the distributed parts. The technique utilizes the modified nodal analysis (MNA) method to do overall description of the network enabling determining sensitivities with respect to b...

The inversion of the one–dimensional Radon transform on the rotation group SO(3) is an ill posed inverse problem which applies to X–ray tomography with polycrystalline materials. This communication presents a novel approach to the numerical inversion of the one–dimensional Radon transform on SO(3). Based on a Fourier slice theorem the discrete inverse Radon transform of a function sampled on th...

An accurate numerical method is established for matrix inversion. It is shown theoretically that the scheme possesses the high order of convergence of seven. Subsequently, the method is taken into account for solving linear systems of equations. The accuracy of the contributed iterative method is clarified on solving numerical examples when the coefficient matrices are ill-conditioned. All of t...

generally, the measured secondary field data is inverted into resistivity using two principal models; the homogeneous half-space model and the layered half-space model. while the homogeneous half-space inversion uses single frequency data, the inversion is done individually for each of the frequencies used, the multi-layer 1d inversion is able to take the data of all frequencies available into ...