This paper deals with an inverse problem of simultaneously determining the dispersion coefficients and the space-dependent source magnitude in 2D advection dispersion equation with finite observations at the final time. The forward problem is solved by using the alternating direction implicit (ADI) finite difference scheme, and then the optimal perturbation algorithm with the regularization par...

In this paper, we prove the co-NP-completeness of the following decision problem: \given a 2-dimensional cellular automaton A, is A injective when restricted to nite conngurations not greater than its length?" In order to prove this result, we introduce two decision problems concerning respectively Turing Machines and tilings that we prove NP-complete. We then present a transformation of proble...

Porosity is one of the key parameters associated with oil reservoirs. Determination of this petrophysical parameter is an essential step in reservoir characterization. Among different linear and nonlinear prediction tools such as multi-regression and polynomial curve fitting, artificial neural network has gained the attention of researchers over the past years. In the present study, two-dimensi...

Abstract In this work, the Mellin transform method was used to obtain solutions for the stress field components in two dimensional (2D) elasticity problems in terms of plane polar coordinates. the Mellin transformation was applied to the biharmonic stress compatibility equation expressed in terms of the Airy stress potential function, and the boundary value problem transformed to an algebraic  ...

A modified 2D focusing inversion method for gravity data is presented in this paper. This iterative inversion method minimizes the area of the causative body and yields a compact density distribution. In order to find the required number of iterations for maximum compactness of the density distribution, the parameter variation function is proposed as a stopping criterion in the inversion proced...

Helicopter-borne frequency-domain electromagnetic (HEM) surveys are used extensively for mineral and groundwater exploration and a number of environmental investigations. To have a meaningful interpretation of the measured multi- frequency HEM data, in addition to the resistivity maps which are provided in each frequency or for some particular depth levels, it is a necessity ...

BACKGROUND AND PURPOSE MR imaging plays an important role in diagnosing MS and other related inflammatory diseases; however, imaging of the spinal cord is still challenging. We hypothesized that a 3D double inversion recovery sequence for cervical spinal cord imaging would be more sensitive in detecting inflammatory lesions than a conventional 2D T2-weighted TSE sequence at 3T. MATERIALS AND ...

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 ...

helicopter-borne frequency-domain electromagnetic (hem) surveys are used extensively for mineral and groundwater exploration and a number of environmental investigations. to have a meaningful interpretation of the measured multi- frequency hem data, in addition to the resistivity maps which are provided in each frequency or for some particular depth levels, it is a necessity to have a suit...

magnetotelluric (mt) method is an electromagnetic method which provides information about subsurface conductivity structures using earth's natural electromagnetic fields. static shift is one of disorders arising from shallow conductors; therefore static shift must be corrected as one of mt data processing steps. in the absence of sufficient information about the near surface distortions, w...