This paper establishes an improved NDIF method for the eigenvalue extraction of two-dimensional acoustic cavities with arbitrary shapes. The NDIF method, which was introduced by the authors in 1999, gives highly accurate eigenvalues despite employing a small number of nodes. However, it needs the inefficient procedure of calculating the singularity of a systemmatrix in the frequency range of in...

in this paper, shielding effectiveness (se) of a perforated enclosure with imperfectly conducting walls is evaluated. to this end, first, an accurate numerical technique based on method of moments (mom) ispresented. in this method, lossy metallic walls of the enclosure are replaced by equivalent electric surfacecurrent sources. then, the impedance boundary condition on the imperfectly conductin...

Introduction: Iterative reconstruction techniques provide better image quality and have the potential for reconstructions with lower imaging dose than classical methods in computed tomography (CT). However, the computational speed is major concern for these iterative techniques. The system matrix calculation during the forward- and back projection is one of the most time- cons...

objective: poverty alleviation is an essential step to achieve economic development. this is why identification exercise is so crucial. traditionally, different aspects of insecurities have not be taken into poverty measurement. many types of insecurities have adverse impacts on household welfare. identifying vulnerability of household can serve identification of the poor households. methodolog...

In this paper, shielding effectiveness (SE) of a perforated enclosure with imperfectly conducting walls is evaluated. To this end, first, an accurate numerical technique based on method of Moments (MoM) ispresented. In this method, lossy metallic walls of the enclosure are replaced by equivalent electric surfacecurrent sources. Then, the impedance boundary condition on the imperfectly conductin...

‎in this paper‎, ‎an approach based on statistical spline model (ssm) and collocation method is proposed to solve volterra-fredholm integral equations‎. ‎the set of collocation nodes is chosen so that the points yield minimal error in the nodal polynomials‎. ‎under some standard assumptions‎, ‎we establish the convergence property of this approach‎. ‎numerical results on some problems are given...

In this article, the radiated noise by a shock-absorber is studied. This particular shock-absorber is used in a heavy-gauge shearing line in order to stop the cut steel sheets. Three steps are followed to evaluate the propagated sound in the surroundings; first of all, the plate vibration response is specified after the impact. Secondly, the edges of the plate are substituted by a set of the mo...

In terms of observational data, there are some problems in the standard Big Bang cosmological model. Inflation era, early accelerated phase of the evolution of the universe, can successfully solve these problems. The inflation epoch can be explained by scalar inflaton field. The evolution of this field is presented by a non-linear differential equation. This equation is considered in FLRW model...