Search results for "A* algorithm"
showing 10 items of 2538 documents
Spintronic properties of Li1.5Mn0.5Z (Z=As, Sb) compounds in the Cu2Sb structure
2015
Abstract We have investigated the spintronic properties of two formula units of Li1.5Mn0.5Z (Z=As, Sb), in the Cu2Sb tetragonal crystal structure based on first-principles density-functional theory calculations, at, and near, their equilibrium (minimum total energy) lattice constants. Two groups of configurations, A and B, are formed for each type of alloy by interchanging Mn with each Li located at four different positions with respect to Li4Z2. Mn has four nearest neighbors in group-A and has one nearest neighbor in group-B. The bonding features of the alloys are compared to the ionic bonding in Li4Z2, and the tetragonal structure of cubic LiMnZ. The magnetic moments of these compounds ar…
New time-dependent Monte Carlo algorithm designed to model three-phase batch reactor processes: applications on 2,4-dinitro-toluene hydrogenation on …
2003
Abstract The hydrogenation of 2,4-dinitro-toluene on a Pd/C catalyst was employed as a test reaction to simulate, by the time-dependent Monte Carlo method, processes occurring in a three-phase batch reactor working at isobar and isotherm conditions. A new time-dependent Monte Carlo algorithm, including an original subroutine useful to reduce the time of the simulations, was developed and implemented in Fortran language. The paper describes the flowchart of the code together with the main technical details and the involved physical and chemical models. Computational characteristics, such as the simulated time to reach surface steady state conditions and the effects of the catalyst morphology…
Comment on “Infrared and Raman selection rules for elastic vibrations of spherical nanoparticles”
2006
This Comment demonstrates again that selection rules established several years ago for the infrared absorption and the Raman scattering by vibrations of a spherical nanoparticle are correct and that the claimed errors about them are wrong.
Analysis of Rectangular Orthotropic Membranes for Mechanical Properties Identification through Load-Displacement Data
2021
In this paper, an innovative procedure is introduced for the identification of the mechanical properties of orthotropic membranes based on load-displacement data. To this end, novel functional forms of the displacement components for rectangular membranes are appropriately introduced. Unknown coefficients of these displacement functions are determined, minimizing the total potential energy of the membrane. The energy method is then combined with an optimization procedure to estimate the elastic constants of the membranes in a straightforward manner. Specifically, a genetic algorithm is used to minimize a properly defined objective function directly related to the sought mechanical propertie…
Reconstruction Problem of Reinforced Concrete Beams under Harmonic Excitations
2007
A damage detection method based on harmonic structural vibrations has been applied to reconstruct realistic damage patterns of reinforced concrete beams. It was shown that the application of a hybrid method (genetic algorithm and Levenberg-Marquardt minimization technique) makes it possible to effectively reconstruct the flexural stiffness drops as small as 10-20% with the maximum error of 4%. The error increases to about 7 to 9% with the presence of 1% measurement noise.
Diagonalization of large matrices: a new parallel algorithm.
2015
On the basis of a dressed matrices formalism, a new algorithm has been devised for obtaining the lowest eigenvalue and the corresponding eigenvector of large real symmetric matrices. Given an N × N matrix, the proposed algorithm consists in the diagonalization of (N - 1)2 × 2 dressed matrices. Both sequential and parallel versions of the proposed algorithm have been implemented. Tests have been performed on a Hilbert matrix, and the results show that this algorithm is up 340 times faster than the corresponding LAPACK routine for N = 10(4) and about 10% faster than the Davidson method. The parallel MPI version has been tested using up to 512 nodes. The speed-up for a N = 10(6) matrix is fair…
A star product on the spherical harmonics
1996
We explicitly define a star product on the spherical harmonics using the Moyal star product on ℝ6, and a polarization equation allowing its restriction on S2.
A general framework for a class of non-linear approximations with applications to image restoration
2018
Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: https://www.sciencedirect.com/science/article/abs/pii/S0377042717301188 Este es el pre-print del siguiente artículo: Candela, V., Falcó, A. & Romero, PD. (2018). A general framework for a class of non-linear approximations with applications to image restoration. Journal of Computational and Applied Mathematics, vol. 330 (mar.), pp. 982-994, que se ha publicado de forma definitiva en https://doi.org/10.1016/j.cam.2017.03.008 This is the pre-peer reviewed version of the following article: Candela, V., Falcó, A. & Romero, PD. (2018). A general framework for a class of non-linear approximations with applic…
On Constraint Handling in Surrogate-Assisted Evolutionary Many-Objective Optimization
2016
Surrogate-assisted evolutionary multiobjective optimization algorithms are often used to solve computationally expensive problems. But their efficacy on handling constrained optimization problems having more than three objectives has not been widely studied. Particularly the issue of how feasible and infeasible solutions are handled in generating a data set for training a surrogate has not received much attention. In this paper, we use a recently proposed Kriging-assisted evolutionary algorithm for many-objective optimization and investigate the effect of infeasible solutions on the performance of the surrogates. We assume that constraint functions are computationally inexpensive and consid…