S.L. Avila

• Dr. Eng.
• Professor (Full) at Federal Institute of Santa Catarina

This article aims to propose and apply a machine learning method to analyze the direction of returns from exchange traded funds using the historical return data of its components, helping to make investment strategy decisions through a trading algorithm. In methodological terms, regression and classification models were applied, using standard data...

Understanding and predicting power consumption behavior helps estimate costs, seek actions to save energy and plan affirmative actions that raise people's awareness. Organized civil society has made efforts in this context. Our contribution is a framework that first extracts knowledge about consumption through an extensive time series analysis of t...

The emerging HVDC technology has been used for long-distance power transmission, increasing flexibility to the power systems, handling asynchronous interconnections, crossing long-distance submarine cables, unusual loading, and generation profiles, and improving energy market relations. The HVDC converter transformers are designed based on system p...

The power operation sector is facing an evolution regarding the adoption of new technologies that, although necessary and unavoidable, add operational complexity to the system. Due to the essence of their activities and the systemic orientation required for their execution, the operation centers are natural information hubs. As far as audio calls a...

Microwave technology has many current applications. It is very useful for food processing, including domestic cooking and warming-up and industrial heating and drying. It heats faster than conventional applications; however, in most cases result in non-uniform temperature distribution. Adequate cavity and equipment designs can reduce the impact of...

Fault diagnostics is essential for improving the reliability of electrical machines applied in smart manufacturing. For many industrial applications, AI-based solutions become viable when combined with edge-computing strategies. It means a framework with limited network bandwidth and computational processing power. The developed approach uses a low...

The health of a rotating electric machine can be evaluated by monitoring electrical and mechanical parameters. As more information is available, it easier can become the diagnosis of the machine operational condition. We built a laboratory test bench to study rotor unbalance issues according to ISO standards. Using the electric stator current harmo...

Optimizing ship power systems with diesel generators such as the platform supply vessel (PSV) has become a pressing issue due to the emission of carbon dioxide. This paper investigates the optimal operation of diesel generators in marine power systems, particularly the PSV. The investigation is mainly focused on carbon dioxide emission and fuel con...

https://github.com/PECCE-IFSC/Otimizacao

The diagnosis of failures in rotating machines has been subject to studies because of its benefits to maintenance improvement. Condition monitoring reduces maintenance costs, increases reliability and availability, and extends the useful life of critical rotating machinery in industry ambiance. Machine learning techniques have been evolving rapidly...

Based on a multiscale modelling of the anhysteretic magnetization taking into account mechanical stress and crystallographic texture effects, an extension of the Jiles-Atherton (J-A) hysteresis model is proposed. The magnetization and the volume fractions given by the multiscale approach are advantageously used in the J-A model to modify the anhyst...

An antenna can be considered as a two-port transducer system characterized by a transfer function that can be frequency-dependent and may have a non-linear phase response. The performance of this complex device is critical for time or frequency-domain ground penetrating radar (GPR) systems. We recently published a framework for GPR antenna design a...

Ground Penetrating Radar is a multidisciplinary Nondestructive Evaluation technique that requires knowledge of electromagnetic wave propagation, material properties and antenna theory. Under some circumstances this tool may require auxiliary algorithms to improve the interpretation of the collected data. Detection, location and definition of target...

—Ground Penetrating Radar is a complex nondestructive evaluation technique where the antenna is the most critical part. The antenna is responsible for transmission and reception of waves at the proper level and frequencies defined in the GPR system specifications. Important GPR features such as resolution and penetration depth depend on its charact...

RESUMO Este informe técnico apresenta uma metodologia para o diagnóstico de defeitos em hidrogeradores através da análise de vibrações em sistemas de monitoramento, utilizando técnicas no domínio do tempo e frequência. A base do monitoramento é composta por sensores de proximidade e acelerômetros, instalados nos mancais da unidade geradora, sensor...

Resumo – Eventos como o apagão de 2001 e a crise energéti-ca iniciada em 2012 impulsionaram no setor o uso de grupos motor-gerador (GMG) como fonte de energia independente. Entretanto, embora este parque continue crescendo, não exis-tem no mercado tecnologias 100% nacionais para a melhoria da produtividade e confiabilidade na operação de grupos ger...

Resumo Pode-se considerar como inestimável a importância que a energia elétrica tem para a sobrevivência e o desenvolvimento socioeconômico da sociedade. O aumento da demanda por energia, o crescimento populacional e tecnológico e o amadurecimento das preocupações ambientais são fatores que atraem crescentes investimentos para produção de energia a...

Resumo: A crescente preocupação com a qualidade dos equipa-mentos eletrônicos fomenta esforços para o desenvolvimento de me-todologias e equipamentos de testes para análise de compatibili-dade eletromagnética (CEM). Atualmente, câmaras reverberantes são foco de estudos como ambiente propício para estes ensaios. Este artigo propõe um processo de car...

This paper presents a hybrid mono/multiobjective optimization approach based on numerical, statistical, and fitness evaluation concerning the conductor positions in a transmission line excitation chamber (TLEC). The field profile and the related indexes of merit, as well as statistical ones, regarding the working volumes (WVs) are used to evaluate...

This paper presents a procedure for evaluating the performance of reverberation chambers, by approximating the maximum working volume in a given configuration. The evaluation of this volume is based on the geometrical and physical constraints, e.g., the ones related to the internal E-field distribution recommended by standards. The importance of th...

This paper presents a procedure for evaluating the performance of reverberation chambers by applying statistical and optimization techniques. The chambers configurations evaluation is based on the trends of geometrical and physical constraints, like the ones related to the internal E-field distribution recommended by standards. The importance of th...

Due to the growing demand for traffic communication, the requirement for reconfigurable antennas for future generation of satellites is growing steadily. This article presents designs examples of reconfigurable satellite contour beam reflector antennas via multi-objective evolutionary optimization. One configuration is composed of shaped reflector...

In order to resolve closely spaced targets in a planar surface normal to the beam, the antenna used in the radar assessment of concrete structures should have a narrow beam width which means a higher directivity. To optimize the field pattern of an antenna it was implemented a procedure that unifies multi-objective genetic algorithms (MGA) and a mo...

http://www.eucap2006.org/

Antennas are one of the most critical parts in ground penetrating radar (GPR) systems. They substantially determine the quality of the obtained GPR raw data [1]. For work on concrete two main types of antenna are used, generally described as either dipoles that operate in close proximity to the material to be surveyed or TEM horns that operate at l...

In this work, a Multi-Niching Multi-Objective Genetic Algorithm is presented for solving multimodal optimization problems. The originality of this algorithm resides in its niching procedure, which maintains population diversity in both objective and design variable spaces. In particular, the clearing of non-dominated individuals in the archive upda...

To be effective a perfectly matched layer (PML) must be reflectionless to all impinging waves over a broad band of frequencies whilst not overly increasing the computational burden. This can be difficult to achieve as one must find a balance between the discretization error, the number of PML layers and the reflection coefficient. This work present...

The result of a multiobjective evolutionary optimization is an efficient solution set surrounded by other candidate solution points. To choose a final solution, we can perform a sensitivity study. Applying this methodology, disturbances that occur in real-world design problems are not neglected. This paper presents an easy way to perform the sensit...

Thèse en co-tutelle avec l'Université Fédérale de Santa Catarina, Florianopolis, Brésil. Texte complet également disponible en portugais.

In order to resolve closely spaced targets in a planar surface normal to the beam, the antenna used in the radar assessment of concrete structures should have a narrow beam width which means a higher directivity. This work presents a procedure to optimize the field pattern of a bow-tie antenna using multi-objective genetic algorithms in conjunction...

To obtain the maximum performance of any device the designer needs to have a large experience in the entire universe where it is inserted. Consequently, more important than to find an adequate optimized solution is to comprehend the whole problem, giving to the designer opportunity to make choices and also to learn about the problem. A complete opt...

This paper presents the application of genetic algorithms in the optimization of an offset reflector antenna. The antenna shape is designed in order to obtain a uniform radiation pattern on the Brazilian territory. Modified genetic operators are proposed with the aim to increase the efficiency of the real coded genetic algorithms used here.

The parameters set of the Jiles-Atherton hysteresis model is identified by using a real coded genetic algorithm. The parameters identification is performed by minimizing the mean squared error between experimental and simulated magnetic field curves. The procedure is validated by comparing experimental and simulated results.

Resumo – Este artigo apresenta uma configuração modificada de Algoritmos Genéticos com codificação real e utilizando cruzamento polarizado e mutação pelo comportamento da população, ambos por variável. Ela será aplicada na modelagem da forma do refletor com abertura circular de uma Antena Refletora Offset na busca do melhor diagrama de radiação par...

1. Abstract This paper shows a procedure suitable for characterization of non-canonical reverberation chambers, whose excitation is carried out by transmission lines. Based on the pre-defined threshold, the figure of merit called "working volume" is defined on the optimization process. It should be emphasized that the reverberation chambers assume...

1. Abstract The use of multimedia tools to illustrate theories is very widespread. This kind of tool facilitates and renders more interesting the learning process. In this paper an educational software for teaching optimization in engineering is showed. The main goals are to give to the educators an attractive computational instrument and provide s...