Marcel Wu

Parameters Estimation of a Horizontal Multilayer Soil Using Genetic Algorithm

This paper presents an optimization methodology by using a genetic algorithm (GA) to obtain the parameters of a soil that can be represented in a multilayer structure. The method uses a curve of experimental apparent resistivity obtained from measurements made in the soil. This experimental curve is compared with another curve of apparent resistivity of the soil, theoretical, produced by the GA. The theoretical curve is based on Sundes Algorithm and is exactly the inverse process used for the horizontal stratification of the soil in multilayers. With both curves in hand, the error produced in the process of soil stratification can be estimated. From the estimated errors, the parameters are optimized. The main difference of this method, comparing the already developed methods is just that, besides optimizing the resistivities ρi and the thicknesses hi of each soil layer, the proposed method also optimizes the layers quantity, seeking the best soil stratification. The obtained results of this paper are compared with other soil stratification methods.

Electromagnetic Problems Solving by Conformal Mapping: A Mathematical Operator for Optimization

Having the property to modify only the geometry of a polygonal structure, preserving its physical magnitudes, the Conformal Mapping is an exceptional tool to solve electromagnetism problems with known boundary conditions. This work aims to introduce a new developed mathematical operator, based on polynomial extrapolation. This operator has the capacity to accelerate an optimization method applied in conformal mappings, to determinate the equipotential lines, the field lines, the capacitance, and the permeance of some polygonal geometry electrical devices with an inner dielectric of permittivity . The results obtained in this work are compared with other simulations performed by the software of finite elements method, Flux .

PEM fuel cell dynamic model for electronic circuit simulator

This paper presents a PEM fuel cell dynamic modeling, to be employed with electronic circuit simulator software - PSIM. Simulations of the proposed model for the fuel-cell, supplying a step-up DC-DC converter are presented. Comparisons with existing models are also made. Practical results are presented in this paper for a Ballard 1.2kW Nexa Power Module for theoretical-experimental comparisons.

Modeling validation of Salient Pole Synchronous Machines from experimental inductances

In this paper, a computer simulation of the Salient Pole Synchronous Machine (SPSM) is presented. This simulation employs a modeling based on the machine self and mutual inductance curves, determined from a methodology, not presented here. These methodology applies the experimental volt-ampere method to obtaining the inductances curves. From these inductance data, using a mathematical methodology, are obtained the derivative inductances curves. The simulated results are confronted with the experimental currents and voltages measured in tests, for purposes of validation of the SPSM modeling from the experimental inductances.

Genetic algorithm applied in a geoelectrical prospecting method

This work presents an optimization methodology using a Genetic Algorithm, to obtain the parameters of a soil that can be represented in a multi layer structure. The method uses a curve of experimental apparent resistivity obtained from measurements made in the soil. This experimental curve is compared with another curve of theoretical apparent resistivity of the soil, produced by the genetic algorithm. The main difference of this method regarding the already developed methods, is just that, besides optimizing the resistivities ρi and the thicknesses hi of each layer, the proposed method also optimizes the layers N quantity, seeking the best soil stratification. The obtained results of this work are compared with others soil stratification methods.