https://repositorio.ufu.br/handle/123456789/5145 Tue, 22 Sep 2026 03:06:39 GMT 2026-09-22T03:06:39Z https://repositorio.ufu.br/handle/123456789/50363 Title: Sistema de avaliação da confiabilidade dielétrica de cabos isolados de alta tensão baseado em descarga parcial como módulo de digital shadow Abstract: The evaluation of the dielectric reliability of medium and high voltage power cables is a very important procedure for the prevention of failures and operational continuity in industrial environments. Insulation degradation, driven by mechanisms such as thermal aging, moisture penetration, and localized defects, manifests itself early through partial discharges, whose systematic monitoring and interpretation make it possible to anticipate critical conditions before asset failure. In this context, the present work proposes a methodology for evaluating the dielectric reliability of medium and high voltage cables from the monitoring of partial discharges, designed to operate as the dielectric evaluation module within a Digital Shadow architecture aimed at the management of electrical assets. The methodology is organized in a sequential pipeline of five steps: (i) signal acquisition by means of sensors (either in offline or online regimes), (ii) separation of signals from partial noise discharges, by hierarchical clustering by Ward's method, (iii) evaluation of dielectric severity by fuzzy logic, (iv) estimation of the cable state in the Weibull reliability curve, through a degradation model and (v) weighting adjustments by the signal quality index and final evaluation by condition ranges based on IEEE Std 400.3 and CIGRE TB 841 guidelines. These methodological procedures, when added together, aim to qualify the reliability of the cable based on its discharge signals. This set must work within the concept of "Digital Shadow", receiving data from the sensors installed in the physical world, processing it and producing, at its end (usually in a cloud system) a coherent physical indication of the state of the (insulation) of the cable under monitoring. Fri, 31 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50363 2026-07-31T00:00:00Z https://repositorio.ufu.br/handle/123456789/50351 Title: Técnicas de Inteligência Artificial aplicadas à otimização multiobjetivo de equipamentos eletromagnéticos saturáveis: um estudo de caso em reatores a núcleo saturado Abstract: This thesis proposes and validates a multi-objective optimization methodology for the design of large-scale Saturated Core Reactors (SCRs), based on replacing three-dimensional Finite Element simulations with Artificial Neural Networks (ANNs) trained as surrogate models. The work begins by contextualizing the design problem of electromagnetic equipment and identifying the research gap concerning the application of ANN-based surrogate models to three-dimensional saturated magnetic structures. A reference reactor, rated at 500 kVAr in a Twin-Trippler topology, was designed, modeled in ANSYS Maxwell software, and experimentally validated through the fabrication of a physical prototype and factory acceptance electrical tests, confirming the accuracy of the adopted computational model. From a simplified model, shown to be equivalent to the detailed manufacturing model, a parametric sweep using Finite Element simulations was conducted to generate a training dataset. A comparative study among machine learning techniques demonstrated the superiority of ANNs in capturing the strongly nonlinear behavior of the equipment under deep saturation, achieving coefficients of determination (R²) above 0.96 for the reactive power and core loss objective functions. The trained ANNs were then employed to exhaustively explore a design space of more than 247 million combinations, enabling the construction of the Pareto frontier between core losses and volume within minutes of processing. The selected optimal design, validated through detailed Finite Element simulation, achieved reductions of 12.86% in magnetic core losses and 14.37% in core volume relative to the reference equipment, while preserving the rated reactive power absorption capacity within acceptable design margins. The results confirm the effectiveness of the proposed methodology as a computationally efficient and experimentally validated design tool for electromagnetic equipment operating under deep magnetic saturation. Mon, 17 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50351 2026-08-17T00:00:00Z https://repositorio.ufu.br/handle/123456789/50337 Title: Estimação do comprimento de antenas de microfita utilizando Support Vector Regression Abstract: In this paper, a Machine Learning technique called Support Vector Regression is applied for regression of squared microstrip patch antennas data for operation under its dominant mode 𝑇𝑀10. The simulation data was gathered through Ansys Electronics Desktop 2022, using the high frequency simulation module HFSS. Simulation results are given in both S and Z parameters for 2 different situations. Firstly, the antenna length 𝐿 is changed from 10 mm to 40 mm in steps of 1 mm. After it, the antenna behaviour is simulated and the frequency range is fixed from 1 GHz to 10 GHz, getting 𝐿 values that satisfies the specified frequency range. Both steps are simulated for 5 different dielectric permittivity 𝜖. With these informations, a database is created, and it will contain data that will be cleaned, sorted out and labeled, then feeded to a Support Vector Regression (SVR) algorithm for training and validation. The generated model is capable of predicting, accurately, the value of 𝐿 for any 𝑓𝑟 within the frequency range established. Tue, 08 Sep 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50337 2026-09-08T00:00:00Z https://repositorio.ufu.br/handle/123456789/50331 Title: Caminhos que os beija-flores me levaram: trajetória da minha formação e carreira docente Abstract: In this memorial, I present a detailed retrospective of my professional and academic trajectory, revisiting the path taken from the early stages of my training to the present moment - a journey culminating in my consolidation as a faculty member at the Federal University of Uberlândia (UFU). This document is not merely a formal requirement for promotion to the rank of Full Professor - the pinnacle of the teaching career in Brazilian federal universities - but rather a living record of sixteen years of dedication to the public university and to the production of knowledge. In drafting these pages, I sought to revisit memories, data, and significant results. My primary aim in providing this level of detail is for the work presented here to transcend mere evaluative formality and serve as an account—particularly for faculty members who have recently joined the teaching profession at a public university. Thus, my intention was not simply to list my output, but to present a critical perspective on everything I have experienced over these years as a faculty member at the Federal University of Uberlândia. I believe that the teaching career, especially when pursued with a commitment to social impact, is one of the most powerful instruments for transforming individuals and realities; it is capable of realizing dreams, fostering critical thinking, and proposing technological and scientific solutions for society. My journey is defined by significant experiences that continuously reinforce one another: the classroom inspires research; research informs outreach; and administration is essential to making teaching and research possible. I conclude this memorial by sharing reflections on my vision and experience in higher education. It is an assessment not only of what I have produced but also of who I have become throughout this process of constant teaching and learning within the university. Fri, 11 Sep 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50331 2026-09-11T00:00:00Z