With the rapid growth of indoor wireless communication systems, the need to accurately model radio wave propagation inside the building environments has increased. Many site-specific methods have been proposed for modeling indoor radio channels. Among these methods, the ray tracing algorithm and the finite-difference time domain (FDTD) method are the most popular ones. The ray tracing approach ...

An analytical treatment of the electron screening effect within an active-electron model is given for positronium formation from helium atoms. A first-order distorted wave approximation with correct boundary conditions is applied to evaluate the transition amplitude. In the range of impact energy for which the introduced perturbative approach is valid, both the total and differential cross sect...

Accurate permeability estimation has always been a concern in determining flow units, assigning appropriate capillary pressure andrelative permeability curves to reservoir rock types, geological modeling, and dynamic simulation.Acoustic method can be used as analternative and effective tool for permeability determination. In this study, a four-step approach is proposed for permeability estimati...

conclusions according to our multimodality imaging approach, hypertrophic cardiomyopathy was the most probable diagnosis. case presentation we describe a 73-year-old woman referred to us for consultation because of a giant negative t wave on her electrocardiography. echocardiography revealed diffuse severe hypertrophy associated with hypertrophied anterolateral papillary muscles with a bifid he...

we usewe use ml shear wave velocity to derive a high resolution 2d ml shear wave velocity map for the iranian plateau. the ml amplitudes and arrival times are routinely measured for the calculation of local magnitude. ml shear wave velocity is very sensitive to the lateral change of crustal thickness and switches between the velocity of lg and sn waves. an lg wave will die out as soon as encoun...

optimization of reservoir parameters is an important issue in petroleum exploration and production. the ant colony optimization(aco) is a recent approach to solve discrete and continuous optimization problems. in this paper, the ant colony optimization is usedas an intelligent tool to estimate reservoir rock properties. the methodology is illustrated by using a case study on shear wave velocity...

the problem of propagation of plane wave including body and surface waves propagating in a transversely isotropic half-space with a depth-wise axis of material symmetry is investigated in details. using the advantage of representation of displacement fields in terms of two complete scalar potential functions, the coupled equations of motion are uncoupled and reduced to two independent equations...