A5002315677- Advanced Electrical Measurement Techniques
- Power Quality and Harmonics
- Non-Destructive Testing Techniques
- Sensor Technology and Measurement Systems
- Magnetic Properties and Applications
- Advancements in PLL and VCO Technologies
- Welding Techniques and Residual Stresses
- Ultrasonics and Acoustic Wave Propagation
- Advanced Fiber Laser Technologies
- Structural Health Monitoring Techniques
- Optical Network Technologies
- Analog and Mixed-Signal Circuit Design
- Electrical and Bioimpedance Tomography
- Scientific Measurement and Uncertainty Evaluation
- Analytical Chemistry and Sensors
- Power Transformer Diagnostics and Insulation
- Rural Development and Agriculture
- Image and Signal Denoising Methods
- Advanced Photonic Communication Systems
- Superconducting Materials and Applications
- Geophysical Methods and Applications
- Advanced Sensor Technologies Research
- Energy Harvesting in Wireless Networks
- Image and Object Detection Techniques
- Nonlinear Photonic Systems
Instituto de Telecomunicações
2014-2025
University of Lisbon
2014-2025
Hospital de São João
2012-2023
Energias de Portugal (Portugal)
2022
Instituto Superior Técnico
2008-2020
OptiGrate (United States)
2020
Centro de Geofísica de Évora
2016
University of Évora
2009-2016
Instituto Politécnico de Lisboa
2007-2015
Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento
2015
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents a system for detection and classification of power quality (PQ) voltage disturbances. The proposed applies the following methods to detect classify PQ disturbances: Digital filtering mathematical morphology are used transients waveform distortions, whereas short- long-duration disturbances (such as sags, swells, interruptions), analysis root-mean-square (RMS) value is...
The estimation of the parameters defects from eddy current nondestructive testing data is an important tool to evaluate structural integrity critical metallic parts. In recent years, several works have reported use artificial neural networks (ANNs) deal with complex relation between and defect properties. To extract relevant features used by ANN, principal component analysis, wavelet decomposition, discrete Fourier transform been proposed. this paper, a method estimate dimensional reported....
In this paper, a new four-electrode sensor for water conductivity measurements is presented. addition to the itself, all signal conditioning implemented together with processing of outputs determine conductivity. The designed in range from 50 mS/m up 5 S/m through correct placement four electrodes inside tube where flows. prototype capable supplying necessary current at measurement frequency, acquiring sine signals across voltage and sampling impedance current. A temperature also included...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new algorithm for the estimation of frequency single-tone signals is presented in this paper. The works domain and based on best fitting a theoretical spectrum signal that windowed using rectangular window sampled signal. Using iterative process, compensates leakage caused by incoherent sampling finite number samples. Due to compensation, provides accurate estimates signal's frequency,...
A new generation of multipurpose measurement equipment is transforming the role computers in instrumentation. The features involve mixed devices, such as analog-to-digital and digital-to-analog converters digital signal processing techniques, that are able to substitute typical discrete instruments like multimeters analyzers. Signal-processing applications frequently use least-squares (LS) sine-fitting algorithms. Periodic signals may be interpreted a sum sine waves with multiple...
Due to the dispersion mismatch between two supermodes of a two-channel coupler, pulse switching cannot be analyzed without taking into account effect intermodal dispersion. Using full numerical simulations, we show influence on all-optical with ultrashort pulses in twin-core fiber couplers. For nonlinear regime, however, only subpicosecond and femtosecond are affected cross state since parallel remains almost unaffected.
The integral nonlinearity (INL) of analog-to-digital converters (ADCs) can be described by a behavioral error model expressed as one-dimensional image in the code domain. This consists low and high frequency components which allow describing ADC performance with small number parameters. paper presents new methods for testing. identification is performed multiharmonic sine fitting time are estimated statistical domain narrow band histogram test using triangular stimulus signal. proposed...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The development and implementation of a digital-signal-processor (DSP)-based portable impedance-measurement instrument is described. circuit sinewave stimulus generated by the device using direct digital synthesizer at desired measurement frequency. sine applied to reference impedance in series with unknown impedance. Two analog-to-digital converters (ADCs) acquire multiple samples two voltages,...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, recent advances of a new digital-signal-processor (DSP)-based impedance measurement instrument under development are presented. The digital signal processing algorithms based on ellipse fitting for the extraction acquired sine parameters so that magnitude and phase can be determined. Special attention is devoted to improvement algorithm's efficiency, i.e., by enabling acquisition...
Energy consumption has increased over the years and, due to dependency on fossil energy, alternative and renewable energy sources have been integrated address environmental concerns. However it is important maintain efficiency, reliability, safety of power grid amid integration different sources. IEEE IEC standards regulate quality define thresholds for events that traditionally detected through specialized algorithms. With machine learning possible detect classify those using deep...
Infecções fúngicas são muitas vezes negligenciados e podem apresentar uma variedade de manifestações clínicas. As micoses sistêmicas consideradas um problema saúde pública, a exemplo da paracoccidioidomicose, criptococose, coccidiodomicose histoplasmose que estão presentes no Maranhão. Este trabalho tem o objetivo avaliar casos internações por crianças 1 4 anos nos municípios do Maranhão 2013 2023. A sua metodologia consiste em estudo epidemiológico transversal com base levantamento dados...
A novel instrument was designed and numerically validated for measuring AC losses in ramped superconducting magnets. These power are expected to be the 1 W 100 range. The improves metrological performance compared existing instruments by reaching a target loss uncertainty order of 0.1 watt. This allows accurate measurement improve magnet modeling. Monte Carlo analysis is used evaluate uncertainty. Such an addresses lack investigation literature this kind measurement, proposed approach can...