References of "Alves Martins, Wallace 50034845"
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See detailIntersymbol and Intercarrier Interference in OFDM Transmissions Through Highly Dispersive Channels
Alves Martins, Wallace UL; Cruz-Roldán, Fernando; Moonen, Marc et al

in Proc. of the 27th European Signal Processing Conference (EUSIPCO-2019) (2019, September)

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See detailOn the Use of Vertex-Frequency Analysis for Anomaly Detection in Graph Signals
Lewenfus, Gabriela; Alves Martins, Wallace UL; Chatzinotas, Symeon UL et al

in Anais do XXXVII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2019) (2019, September)

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See detailTime-Deconvolutive CNMF for Multichannel Blind Source Separation
Dias, Thadeu; Biscainho, Luiz Wagner; Alves Martins, Wallace UL

in Anais do XXXVII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2019) (2019, September)

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See detailSemi-blind Data-Selective and Multiple Threshold Volterra Adaptive Filtering
Barboza da Silva, Felipe; Alves Martins, Wallace UL

in Circuits, Systems, and Signal Processing (2019)

This work proposes the use of data-selective semi-blind schemes in order to decrease the amount of data used to train the adaptive filters that employ Volterra series, while reducing its computational ... [more ▼]

This work proposes the use of data-selective semi-blind schemes in order to decrease the amount of data used to train the adaptive filters that employ Volterra series, while reducing its computational complexity. It is also proposed a data-selective technique that exploits the structure of Volterra series, employing a different filter for each of its kernels. The parameter vector of these filters grows as the order of the kernel increases. Therefore, by assigning larger error thresholds to higher-order filters, it is possible to decrease their update rates, thus reducing the overall computational complexity. Results in an equalization setup indicate that both proposals are capable of achieving promising results in terms of mean square error and bit error rate at low computational complexity, and in the case of semi-blind algorithms, using much less training data. [less ▲]

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See detailConvex Combination of Constraint Vectors for Set-membership Affine Projection Algorithms
Nagashima Ferreira, Tadeu; Alves Martins, Wallace UL; Lima, Markus et al

in Proc. of IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) (2019, May)

Set-membership affine projection (SM-AP) adaptive filters have been increasingly employed in the context of online data-selective learning. A key aspect for their good performance in terms of both ... [more ▼]

Set-membership affine projection (SM-AP) adaptive filters have been increasingly employed in the context of online data-selective learning. A key aspect for their good performance in terms of both convergence speed and steady-state mean-squared error is the choice of the so-called constraint vector. Optimal constraint vectors were recently proposed relying on convex optimization tools, which might some- times lead to prohibitive computational burden. This paper proposes a convex combination of simpler constraint vectors whose performance approaches the optimal solution closely, utilizing much fewer computations. Some illustrative examples confirm that the sub-optimal solution follows the accomplishments of the optimal one. [less ▲]

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See detailAchievable Data Rate of DCT-based Multicarrier Modulation Systems
Cruz-Roldán, Fernando; Alves Martins, Wallace UL; Sergio Ramirez Diniz, Paulo et al

in IEEE Transactions on Wireless Communications (2019), 18(3), 1739-1749

This paper aims at studying the achievable data rate of discrete cosine transform (DCT)-based multicarrier modulation (MCM) systems. To this end, a general formulation is presented for the full ... [more ▼]

This paper aims at studying the achievable data rate of discrete cosine transform (DCT)-based multicarrier modulation (MCM) systems. To this end, a general formulation is presented for the full transmission/reception process of data in Type-II even DCT and Type-IV even DCT-based systems. The paper focuses on the use of symmetric extension (SE) and zero padding (ZP) as redundancy methods. Furthermore, three cases related to the channel order and the length of the redundancy are studied. In the first case, the channel order is less than or equal to the length of the redundancy. In the second and third cases, the channel order is greater than the length of the redundancy; the interference caused by the channel impulse response is calculated, and theoretical expressions for their powers are derived. These expressions allow studying the achievable data rate of DCT-based MCM systems, besides enabling the comparison with the conventional MCM based on the discrete Fourier Transform. [less ▲]

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See detailNormalized LMS Algorithm and Data-selective Strategies for Adaptive Graph Signal Estimation
Jorge Mendes Spelta, Marcelo; Alves Martins, Wallace UL

in Signal Processing (2019)

This work proposes a normalized least-mean-squares (NLMS) algorithm for online estimation of bandlimited graph signals (GS) using a reduced number of noisy measurements. As in the classical adaptive ... [more ▼]

This work proposes a normalized least-mean-squares (NLMS) algorithm for online estimation of bandlimited graph signals (GS) using a reduced number of noisy measurements. As in the classical adaptive filtering framework, the resulting GS estimation technique converges faster than the least-mean-squares (LMS) algorithm while being less complex than the recursive least-squares (RLS) algorithm, both recently recast as adaptive estimation strategies for the GS framework. Detailed steady-state mean-squared error and deviation analyses are provided for the proposed NLMS algorithm, and are also employed to complement previous analyses on the LMS and RLS algorithms. Additionally, two different time-domain data-selective (DS) strategies are proposed to reduce the overall computational complexity by only performing updates when the input signal brings enough innovation. The parameter setting of the algorithms is performed based on the analysis of these DS strategies, and closed formulas are derived for an accurate evaluation of the update probability when using different adaptive algorithms. The theoretical results predicted in this work are corroborated with high accuracy by numerical simulations. [less ▲]

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