Leonimer Flávio de Melo

Dr. Leonimer Flávio de Melo

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
12 May 2023 in IEEE Sensors Journal
Verified
Journal Article
Closed access
DBDaniel S. Batista
Daniel S. Batista
FGFrancisco Granziera
Francisco Granziera
MTMarcelo Tosin
Marcelo Tosin
LMLeonimer Flávio de Melo
Leonimer Flávio de Melo
This paper presents a new formulation for attitude-independent calibration of three-axis magnetometers. The proposed solution employs a Non-Linear Least Squares (NLLS) estimator that uses the non-linear sensor model proposed by Foster and Elkaim in the well-known Extended Two-Step (ETS) algorithm. Our solution has several advantages over ETS and is more straightforward to implement than many subsequent algorithms. It enables the calculation of the calibration parameters’ uncertainties and does not require the assumption that all magnetometer measurements have a constant magnetic field magnitude. The former is essential for evaluating calibration quality, while the latter may be required for on-orbit magnetometer calibration. However, the NLLS has the drawback of requiring an initial parameter estimation to ensure convergence. Therefore, our work presents a new technique to calculate the scale factors and offsets for initializing the NLLS. Simulations and practical implementations demonstrate that our method performs similarly to a recently computed analytical solution of the ETS. Furthermore, a Monte Carlo simulation shows that the NLLS algorithm provides a slightly better estimation of the scale factors than the ETS, in addition to the abovementioned advantages.

27 October 2014 in International Journal of Systems Science
Verified
Journal Article
Closed access
RGRicardo Enrique Gutiérrez-Carvajal
Ricardo Enrique Gutiérrez-Carvajal
LMLeonimer Flávio de Melo
Leonimer Flávio de Melo
JRJoão Maurício Rosário
João Maurício Rosário
Jose Antonio Tenreiro MachadoJose Antonio Tenreiro Machado
Jose Antonio Tenreiro Machado
While fractional calculus (FC) is as old as integer calculus, its application has been mainly restricted to mathematics. However, many real systems are better described using FC equations than with integer models. FC is a suitable tool for describing systems characterised by their fractal nature, long-term memory and chaotic behaviour. It is a promising methodology for failure analysis and modelling, since the behaviour of a failing system depends on factors that increase the model's complexity. This paper explores the proficiency of FC in modelling complex behaviour by tuning only a few parameters. This work proposes a novel two-step strategy for diagnosis, first modelling common failure conditions and, second, by comparing these models with real machine signals and using the difference to feed a computational classifier. Our proposal is validated using an electrical motor coupled with a mechanical gear reducer.

28 April 2025 in Sensors
Verified
Journal Article
Open access
PDF file
Jessica LopesJessica Lopes
Jessica Lopes
Sylvio Barbon JuniorSylvio Barbon Junior
Sylvio Barbon Junior
LMLeonimer Flávio de Melo
Leonimer Flávio de Melo
With the increasing demand for time-series analysis, driven by the proliferation of IoT devices and real-time data-driven systems, detecting change points in time series has become critical for accurate short-term prediction. The variability in patterns necessitates frequent analysis to sustain high performance by acquiring the hyperparameter. The Cumulative Sum (CUSUM) method, based on calculating the cumulative values within a time series, is commonly used for change detection due to its early detection of small drifts, simplicity, low computational cost, and robustness to noise. However, its effectiveness heavily depends on the hyperparameter configuration, as a single setup may not be universally suitable across the entire time series. Consequently, fine-tuning is often required to achieve optimal results, yet this selection process is traditionally performed through trial and error or prior expert knowledge, which introduces subjectivity and inefficiency. To address this challenge, several strategies have been proposed to facilitate hyperparameter optimizations, as traditional methods are impractical. Meta-learning-based techniques present viable alternatives for periodic hyperparameter optimization, enabling the selection of configurations that adapt to dynamic scenarios. This work introduces a meta-modeling scheme designed to automate the recommendation of hyperparameters for the CUSUM algorithm. Benchmark datasets from the literature were used to evaluate the proposed framework. The results indicate that this framework preserves high accuracy while significantly reducing time requirements compared to Grid Search and Genetic Algorithm optimization.

26 January 2010 in Mathematical Problems in Engineering
Verified
Journal Article
Open access
PDF file
LMLeonimer Flávio de Melo
Leonimer Flávio de Melo
JJJose Fernando Mangili Junior
Jose Fernando Mangili Junior
In the mobile robotic systems, a precise estimate of the robot pose with the intention of the optimization in the path planning is essential for the correct performance, on the part of the robots, for tasks that are destined to it. This paper describes the use of RF digital signal interacting with beacons for computational triangulation in the way to provide a pose estimative at bidimensional indoor environment, where GPS system is out of range. This methodology takes advantage of high‐performance multicore DSP processors to calculate ToF of the order about ns. Sensors data like odometry, compass, and the result of triangulation Cartesian estimative, are fused for better position estimative. It uses a mathematical and computational tool for nonlinear systems with time‐discrete sampling for pose estimative calculation of mobile robots, with the utilization of extended Kalman filter (EKF). A mobile robot platform with differential drive and nonholonomic constraints is used as a base for state space, plants and measurements models that are used in the simulations and validation of the experiments.

19 December 2025 in Sustainability
Verified
Journal Article
Open access
PDF file
Rodolfo Augusto KanashiroRodolfo Augusto Kanashiro
Rodolfo Augusto Kanashiro
JPJuliani Chico Piai Paiva
Juliani Chico Piai Paiva
WNWillian Ricardo Bispo Murbak Nunes
Willian Ricardo Bispo Murbak Nunes
LMLeonimer Flávio de Melo
Leonimer Flávio de Melo
The use of underwater vehicles, either remotely operated vehicles (ROVs) or autonomous underwater vehicles (AUVs), has become increasingly relevant in the operation and maintenance (O&M) routines of offshore wind farms. This article provides a critical review of how these platforms are being integrated into inspection and maintenance tasks, contributing not only to safer and more precise operations but also to greater autonomy in challenging marine environments. Beyond the technical and operational aspects, this review highlights their growing connection with artificial intelligence, digital twins, and multi-robot collaboration. The studies analyzed indicate a progressive shift away from conventional methods, traditionally dependent on crewed vessels and manual inspections, toward more automated, sustainable, and integrated approaches that align with the environmental and social commitments of the offshore wind sector. Finally, emerging trends and persisting obstacles, notably energy autonomy, are discussed, outlining the requirements for consolidating a robust, connected, and sustainability-oriented model for offshore maintenance.

1 January 2006
Verified
Conference Paper
Closed access
LMLeonimer Flávio de Melo
Leonimer Flávio de Melo
JRJoao Mauricio Rosario
Joao Mauricio Rosario
With the fast innovation of the hardware and software technologies in embedded systems area, with application in the robotics and automation, more and more it becomes necessary the development of applications based on methodologies that facilitate future modifications, updates and increments in the original projected system. In this way, this article presents a system of opened architecture, distributing the several control actions in growing levels of complexity and using resources of reconfigurable computing proposal oriented to embedded systems implementation. Software and the hardware are structuralized in independents blocks, with connection through common bus. Is presented the functional blocks where the use of DSP processor board is illustrated for local control level. The supervisory control level is implemented in an IBM PC platform and is connected with the local control level, in the robot, through Ethernet WI-FI link. Also are seen the control blocks that use reprogrammable logic components (FPGA) hardware projected for sensors fusion control interface and actuators controllers and the study and applications of new structures control that possibility good performance in relation to the parameter variations. The sensors, actuators, RF transceiver unit, and others necessary peripheral components for the project implementation with their implementation blocks are listed in the article.