Diogo B. Oliveira

Meshless Local Petrov-Galerkin Approach in Solving Microwave Guide Problems

This paper describes a meshless approach to obtain solutions for propagating microwave problems. The Meshless Local Petrov-Galerkin (MLPG) method is used, based on a local weak form tested with the Heaviside step function. The field is approximated by the Point Interpolation method using radial basis function with additional polynomial basis (RPIMp). TEAM workshop problem 18 is solved and its solution is compared with references from the literature. The results are in good agreement, showing that MLPG can be used as a good alternative to finite elements for this kind of problems.

A Closed-Form Solution for Untransposed Transmission-Lines Fault Location With Nonsynchronized Terminals

This paper introduces a novel method for fault location in alternate current transmission lines relying on the voltage and current measurements in both line ends. The novelty of this method lies in the fact that there is no need for terminal synchronization and it can be applied to general untransposed transmission lines. The proposed formulation only applies a closed-form solution; thus, no iterative algorithm is required. Several simulated and real-world results are presented, and they show the effectiveness of the proposed approach.

A Closed-Form Solution for Transmission-Line Fault Location Without the Need of Terminal Synchronization or Line Parameters

This letter introduces a novel method for fault location in alternate current transmission lines where neither the line parameters nor terminals synchronization is needed. As opposed to the previous works, it introduces a closed-form solution instead of iterative methods. The results are presented for simulated and real-world problems, indicating that the proposed algorithm attains good performance in the tested cases.

Meshless Local Petrov-Galerkin in solving microwave guide problems

This paper describes a meshless approach to obtain accurate solutions for propagating microwave problems. The Meshless Local Petrov-Galerkin (MLPG) method, with the Heaviside step test functions and Radial basis point interpolation method (RPIM) shape functions, is used. Results are obtained for a two-dimensional model and are compared with a consolidated Finite Element Method (FEM).

Dynamic Multiobjective Clonal Selection Algorithm for Engineering Design

We propose a Multiobjective Clonal Selection Algorithm (MCSA) with dynamic variation of its main parameters for the solution of engineering design problems. The MCSA performs a cloning process using different probability distributions, in which the mutation strengths are guided based on a logarithmic rule and on information implicitly created by a simple differential evolution technique. This feature results in a self-adapting search in the algorithm. The efficiency of the MCSA is studied comparing its performance with the Nondominated Sorting Genetic Algorithm II (NSGA-II) in analytical test problems and also in the design of a microwave heating device. The MCSA has outperformed the NSGA-II in all problems investigated.

Design of a Microwave Applicator for Water Sterilization Using Multiobjective Optimization and Phase Control Scheme

This paper presents a methodology based on multiobjective evolutionary optimization and a phase control scheme to design a microwave heating applicator for water sterilization. The optimization problem is formulated in terms of two objective functions: one to maximize the amount of water and the other to minimize the energy spent. The device is modeled as a lossy dielectric multilayer irradiated by two microwave sources. The phase control is done by allowing one of the sources to move. By applying the developed methodology, an efficient applicator is obtained.

Hybrid Analytical-FEM Method for Microwave Heating Analysis in a Single Mode Cavity

This paper describes an approach to solve the thermal-electromagnetic problem inside a single mode applicator loaded with a ceramic sample. The FEM is combined with analytical techniques to solve the electromagnetic problem. We obtain a fast, simple and accurate method that allows performance investigation of the single mode cavity during the whole heating process. A key feature of the method is to permit iris aperture and short position to vary during the heating. The dependence upon temperature of the complex permittivity of the load is included in the model. The simulation of a thin cylinder ceramic shows that the approach proposed is capable to provide accurate results with low computational cost.

Designing a multilayer microwave heating device using a multiobjective genetic algorithm

In this paper, we propose a multiobjective evolutionary approach to design a microwave heating device. The goal is to heat the maximum amount of water, above certain temperature, and spending the minimum energy. The device is modeled as a loss multilayer dielectric irradiated by microwave power. The resulting bi-objective problem is then solved using SPEA2 and a set of solutions is obtained. The results show that SPEA2 finds a higher number of non-dominated solution when compared with the traditional approaches used in this problem, within lower computational cost.