Gustavo Fraidenraich

Dr. Gustavo Fraidenraich

orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

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

Representative Publications

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21 December 2018 in IEEE Geoscience and Remote Sensing Letters
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Journal Article
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FGFernando Almeida Garcia
Fernando Almeida Garcia
ARAndrea Carolina Flores Rodriguez
Andrea Carolina Flores Rodriguez
GFGustavo Fraidenraich
Gustavo Fraidenraich
JFJose Candido S. Santos Filho
Jose Candido S. Santos Filho
This letter presents a novel and exact formulation for the probability of detection of a cell-averaging, constant false-alarm rate (CFAR) radar system operating in a homogeneous Weibull clutter environment. We consider a realistic scenario with both target returns and clutter residues within the cell under test by the radar processing. In passing, we derive novel closed-form expressions for the probability density function and the cumulative distribution function of the sum of an exponentially fluctuating target embedded in Weibull clutter. The derived exact expressions are given in terms of both: 1) bivariate Fox H-function, for which we provide a portable and efficient MATHEMATICA code and 2) easily computable series representations. The validity of all expressions is confirmed via Monte Carlo simulation. The derived results are compared with the idealized Neyman-Pearson detector so as to quantify the CFAR losses, and they indicate that even a small change in the shape parameter of the clutter distribution can significantly affect the radar detection performance.

22 January 2021 in IEEE Access
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Journal Article
Open access
Felipe Augusto Pereira de FigueiredoFelipe Augusto Pereira de Figueiredo
Felipe Augusto Pereira de Figueiredo
MFMichelle S. P. Facina
Michelle S. P. Facina
RFRicardo Coelho Ferreira
Ricardo Coelho Ferreira
YAYun Ai
Yun Ai
RRRukhsana Ruby
Rukhsana Ruby
GFGustavo Fraidenraich
Gustavo Fraidenraich
Despite many studies already published on large intelligent surfaces (LIS), there are still some gaps in mathematical models in the face of possible scenarios. In this work, we evaluate the performance of a single-input single-output (SISO) system in which an LIS acts as a controllable scatterer. We consider that the direct link between the transmitting and receiving devices is non-existent due to a blockage. Quantization phase errors at the LIS are considered since a high precision configuration of the reflection phases is not always feasible. We derive exact closed-form expressions for the spectral efficiencies, outage probabilities, and average symbol error rate (SER) of different modulations schemes. We assume a more comprehensive scenario in which b bits are dedicated to the phase adjustment of the LIS' elements. Based on Monte Carlo simulations, we prove the excellent accuracy of our approach and investigate the behavior of the power scaling law and the power required to reach a specific capacity, depending on the number of reflecting elements. We show that an LIS with approximately fifty elements and four dedicated bits for phase quantization outperforms the conventional system without LIS.

7 May 2021 in IEEE Access
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Journal Article
Open access
DLDimas Augusto Mendes Lemes
Dimas Augusto Mendes Lemes
TCThales Wulfert Cabral
Thales Wulfert Cabral
GFGustavo Fraidenraich
Gustavo Fraidenraich
LMLuis Geraldo Pedroso Meloni
Luis Geraldo Pedroso Meloni
ELEduardo Rodrigues De Lima
Eduardo Rodrigues De Lima
FNFernando Bauer Neto
Fernando Bauer Neto
This work investigates the efficiency of the process of load disaggregation, considering only the values of active power. To perform the task, we use data collected from the NILM (Non-Intrusive Load Monitoring) measurement method, presented in the Rainforest Automation Energy Dataset (RAE) and Reference Energy Disagreggation Dataset (REDD) database. A strategy of assigning labels using combinations of equipment in use, by status ON/OFF, and also by choosing an appropriate temporal data window is discussed. Also, the performance of very well-known machine learning algorithms such as k-Nearest Neighbor (kNN), Decision Tree, and Random Forest are evaluated. The results show a very efficient and low computer complexity strategy presenting values of F1-Score above 95%, for RAE and REDD database. As presented in table I, the proposed approach presents the highest F1-Score, compared to other methods in the literature, considering all appliances in the REDD database. The greatest benefit of the approach consists in the possibility of applying the disaggregation process in a household without smart outlets, under the restriction that the training and test houses hold identical or similar appliances.

12 October 2019 in Sensors
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Journal Article
Open access
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CDClaudio Ferreira Dias
Claudio Ferreira Dias
ELEduardo Rodrigues de Lima
Eduardo Rodrigues de Lima
GFGustavo Fraidenraich
Gustavo Fraidenraich
We derive exact closed-form expressions for Long Range (LoRa) bit error probability and diversity order for channels subject to Nakagami-m, Rayleigh and Rician fading. Analytical expressions are compared with numerical results, showing the accuracy of our proposed exact expressions. In the limiting case of the Nakagami and Rice parameters, our bit error probability expressions specialize into the non-fading case.

6 August 2018 in IEEE Transactions on Signal Processing
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Journal Article
Closed access
BSBruno Silva
Bruno Silva
GFGustavo Fraidenraich
Gustavo Fraidenraich
In pulsed Doppler radars, subsampling causes incorrect estimates of the radial velocity of the detected targets whenever its related Doppler frequency is greater than the pulse repetition frequency of the radar. The classic Chinese remainder theorem is a well-known method to overcome this problem. On the other hand, the robust Chinese remainder theorem is a search-based algorithm that, under some conditions, can guarantee the correct estimation of the Doppler frequency. In this paper, we have derived the exact probability of detection for both methods applied in a pulsed Doppler radar. Simulations have been compared to the analytical results and have shown an excellent agreement.

30 June 2022 in IEEE Geoscience and Remote Sensing Letters
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Journal Article
Closed access
LJLenin Patricio Jiménez Jiménez
Lenin Patricio Jiménez Jiménez
FGFernando Almeida Garcia
Fernando Almeida Garcia
MAMaria Cecilia Luna Alvarado
Maria Cecilia Luna Alvarado
GFGustavo Fraidenraich
Gustavo Fraidenraich
ELEduardo Rodrigues de Lima
Eduardo Rodrigues de Lima
In this letter, we provide a general cell-averaging constant false alarm rate (CA-CFAR) performance analysis considering homogeneous Weibull-distributed clutter environments. To do so, we provide generalized expressions for the probability of detection (PD) and probability of false alarm (PFA). Notably, these expressions permit arbitrary values for the shape parameter of the Weibull interference. So far, all CA-CFAR performance analyses were carried out by setting the shape parameter of the Weibull samples within the CFAR window equal to one, which narrows the overall evaluation spectrum. In this study, we allow the shape parameter to take values greater than or equal to one—regime of paramount importance in many practical applications—and still manage to derive manageable and easy-to-implement solutions. All our expressions are confirmed via Monte-Carlo simulations. Numerical results indicate that radar detection is improved as the shape parameter increases.