Agostinho Júnior

Mr. Agostinho Júnior

University of Pernambuco
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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22 March 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
LSLeandro Silva
Leandro Silva
AJAgostinho Júnior
Agostinho Júnior
GAGeorge Azevedo
George Azevedo
SOSergio C. Oliveira
Sergio C. Oliveira
BFBruno José Torres Fernandes
Bruno José Torres Fernandes
The technological growth of the last decades has brought many improvements in daily life, but also concerns on how to deal with electronic waste. Electrical and electronic equipment waste is the fastest-growing rate in the industrialized world. One of the elements of electronic equipment is the printed circuit board (PCB) and almost every electronic equipment has a PCB inside it. While waste PCB (WPCB) recycling may result in the recovery of potentially precious materials and the reuse of some components, it is a challenging task because its composition diversity requires a cautious pre-processing stage to achieve optimal recycling outcomes. Our research focused on proposing a method to evaluate the economic feasibility of recycling integrated circuits (ICs) from WPCB. The proposed method can help decide whether to dismantle a separate WPCB before the physical or mechanical recycling process and consists of estimating the IC area from a WPCB, calculating the IC’s weight using surface density, and estimating how much metal can be recovered by recycling those ICs. To estimate the IC area in a WPCB, we used a state-of-the-art object detection deep learning model (YOLO) and the PCB DSLR image dataset to detect the WPCB’s ICs. Regarding IC detection, the best result was obtained with the partitioned analysis of each image through a sliding window, thus creating new images of smaller dimensions, reaching 86.77% mAP. As a final result, we estimate that the Deep PCB Dataset has a total of 1079.18 g of ICs, from which it would be possible to recover at least 909.94 g of metals and silicon elements from all WPCBs’ ICs. Since there is a high variability in the compositions of WPCBs, it is possible to calculate the gross income for each WPCB and use it as a decision criterion for the type of pre-processing.

2 October 2024 in Knowledge-Based Systems
Verified
Journal Article
Closed access
AJAgostinho Júnior
Agostinho Júnior
LSLeandro Silva
Leandro Silva
JAJoão V. R. de Andrade
João V. R. de Andrade
GAGeorge Azevedo
George Azevedo
BFBruno José Torres Fernandes
Bruno José Torres Fernandes

19 October 2022 in Sensors
Verified
Journal Article
Open access
PDF file
GAGeorge Azevedo
George Azevedo
BFBruno José Torres Fernandes
Bruno José Torres Fernandes
LSLeandro Silva
Leandro Silva
AJAgostinho Júnior
Agostinho Júnior
RARogério Pontes Araujo
Rogério Pontes Araujo
Francisco CruzFrancisco Cruz
Francisco Cruz
Computer vision techniques can monitor the rotational speed of rotating equipment or machines to understand their working conditions and prevent failures. Such techniques are highly precise, contactless, and potentially suitable for applications without massive setup changes. However, traditional vision sensors collect a significant amount of data to process and measure the rotation of high-speed systems, and they are susceptible to motion blur. This work proposes a new method for measuring rotational speed processing event-based data applied to high-speed systems using a neuromorphic sensor. This sensor produces event-based data and is designed to work with high temporal resolution and high dynamic range. The main advantages of the Event-based Angular Speed Measurement (EB-ASM) method are the high dynamic range, the absence of motion blurring, and the possibility of measuring multiple rotations simultaneously with a single device. The proposed method uses the time difference between spikes in a Kernel or Window selected in the sensor frame range. It is evaluated in two experimental scenarios by measuring a fan rotational speed and a Router Computer Numerical Control (CNC) spindle. The results compare measurements with a calibrated digital photo-tachometer. Based on the performed tests, the EB-ASM can measure the rotational speed with a mean absolute error of less than 0.2% for both scenarios.

16 January 2025 in IEEE Sensors Journal
Verified
Journal Article
Open access
GAGeorge Azevedo
George Azevedo
LSLeandro Silva
Leandro Silva
AJAgostinho Júnior
Agostinho Júnior
RARogério Pontes Araujo
Rogério Pontes Araujo
BFBruno José Torres Fernandes
Bruno José Torres Fernandes
Monitoring rotating machines is essential for evaluating operations, preventing failures, and improving efficiency. Traditional rotational measurement methods, like magnetic induction or optical sensors, typically require dedicated hardware for each rotating part, making them costly and complex to implement, especially in industrial scenarios. The challenge intensifies when multiple rotations must be measured simultaneously. This study introduces a novel method using a single event-based vision sensor, or dynamic vision sensor (DVS), which offers asynchronous pixel activation, high temporal resolution, and a wide dynamic range. Unlike traditional frame-based sensors, which require high frame rates and generate large data volumes, the DVS analyzes event streams and processes signals to identify crossing edges and time intervals. This enables simultaneous measurement of multiple rotating parts. The method was tested on a fan propeller, a CNC lathe, and drone propellers, demonstrating a relative mean absolute error of around 0.5%. This method allows safe distance measurements without altering the original production line due to its non-contact nature.

2 June 2020 in bioRxiv
Verified
Preprint
Open access
PDF file
JGJuliana Carneiro Gomes
Juliana Carneiro Gomes
AMAras Ismael Masood
Aras Ismael Masood
LSLeandro Silva
Leandro Silva
JFJanderson Ferreira
Janderson Ferreira
AJAgostinho Júnior
Agostinho Júnior
Wellington Pinheiro dos SantosWellington Pinheiro dos Santos
Wellington Pinheiro dos Santos
The proliferation of the SARS-Cov-2 virus to the whole world caused more than 250,000 deaths worldwide and over 4 million confirmed cases. The severity of Covid-19, the exponential rate at which the virus proliferates, and the rapid exhaustion of the public health resources are critical factors. The RT-PCR with virus DNA identification is still the benchmark Covid-19 diagnosis method. In this work we propose a new technique for representing DNA sequences: they are divided into smaller sequences with overlap in a pseudo-convolutional approach, and represented by co-occurrence matrices. This technique analyzes the DNA sequences obtained by the RT-PCR method, eliminating sequence alignment. Through the proposed method, it is possible to identify virus sequences from a large database: 347,363 virus DNA sequences from 24 virus families and SARS-Cov-2. Experiments with all 24 virus families and SARS-Cov-2 (multi-class scenario) resulted 0.822222 ± 0.05613 for sensitivity and 0.99974 ± 0.00001 for specificity using Random Forests with 100 trees and 30% overlap. When we compared SARS-Cov-2 with similar-symptoms virus families, we got 0.97059 ± 0.03387 for sensitivity, and 0.99187 ± 0.00046 for specificity with MLP classifier and 30% overlap. In the real test scenario, in which SARS-Cov-2 is compared to Coronaviridae and healthy human DNA sequences, we got 0.98824 ± 001198 for sensitivity and 0.99860 ± 0.00020 for specificity with MLP and 50% overlap. Therefore, the molecular diagnosis of Covid-19 can be optimized by combining RT-PCR and our pseudo-convolutional method to identify SARS-Cov-2 DNA sequences faster with higher specificity and sensitivity.

31 March 2025
Verified
Conference Paper
Open access
JAJoão V. R. de Andrade
João V. R. de Andrade
AJAgostinho Júnior
Agostinho Júnior
GPGuilherme Carvalho Pereira
Guilherme Carvalho Pereira
Cristian Millán-AriasCristian Millán-Arias
Cristian Millán-Arias
BFBruno José Torres Fernandes
Bruno José Torres Fernandes
Alexandre M.A. MacielAlexandre M.A. Maciel
Alexandre M.A. Maciel