Finite field transforms and symmetry groups. - Ricardo M. Campello de Souza; Patrick Guy Farrell (Discret. Math., 1985)

Faster DTMF Decoding. - Juliano B. Lima; Ricardo M. Campello de Souza; Hélio M. de Oliveira; M. M. Campello de Souza (ICT, 2004)

The Discrete Cosine Transform over Prime Finite Fields. - M. M. Campello de Souza; Hélio M. de Oliveira; Ricardo M. Campello de Souza; M. M. Vasconcelos (ICT, 2004)

Security of public-key cryptosystems based on Chebyshev polynomials over prime finite fields. - Juliano B. Lima; Ricardo M. Campello de Souza; Daniel Panario (ISIT, 2008)

Fragile watermarking using finite field trigonometrical transforms. - Renato J. Cintra; Vassil S. Dimitrov; Hélio M. de Oliveira; Ricardo M. Campello de Souza (Signal Process. Image Commun., 2009)

The finite field fractional Fourier transform. - Juliano B. Lima; Ricardo M. Campello de Souza (ICASSP, 2010)

Public-key encryption based on Chebyshev polynomials over GF(q). - Juliano B. Lima; Daniel Panario; Ricardo M. Campello de Souza (Inf. Process. Lett., 2010)

Finite field trigonometric transforms. - Juliano B. Lima; Ricardo M. Campello de Souza (Appl. Algebra Eng. Commun. Comput., 2011)

Multiuser communication based on the discrete fractional fourier transform. - Juliano B. Lima; Ricardo M. Campello de Souza; Daniel C. Cunha 001 (ICC, 2012)

Matrix expansions for computing the discrete hartley transform for blocklength N ≡ 0 (mod 4). - R. C. de Oliveira; Ricardo M. Campello de Souza; Hélio M. de Oliveira (LATINCOM, 2012)

Histogram Uniformization for Digital Image Encryption. - Juliano B. Lima; Ricardo M. Campello de Souza (SIBGRAPI, 2012)

The fractional Fourier transform over finite fields. - Juliano B. Lima; Ricardo M. Campello de Souza (Signal Process., 2012)

Minimum multiplicative complexity algorithm for computing a single component of the discrete Fourier transform. - Gilson Jerônimo da Silva Jr.; Ricardo Menezes Campello de Souza (Digit. Signal Process., 2013)

A trigonometric approach for Chebyshev polynomials over finite fields. - Juliano B. Lima; Daniel Panario; Ricardo M. Campello de Souza (Applied Algebra and Number Theory, 2014)

Fractional number-theoretic transforms based on matrix functions. - Juliano B. Lima; Ricardo M. Campello de Souza; Paulo Hugo E. S. Lima (ICASSP, 2014)

A finite field cosine transform-based image processing scheme for color image encryption. - Juliano B. Lima; Edmar S. da Silva; Ricardo M. Campello de Souza (GlobalSIP, 2015)

Genomic Imaging Based on Codongrams and a^2grams. - E. A. Bouton; Hélio M. de Oliveira; Ricardo M. Campello de Souza; N. S. Santos-Magalhães (CoRR, 2015)

A Low-throughput Wavelet-based Steganography Audio Scheme. - P. Carrion; Hélio M. de Oliveira; Ricardo M. Campello de Souza (CoRR, 2015)

A Full Frequency Masking Vocoder for Legal Eavesdropping Conversation Recording. - R. F. B. Sotero Filho; Hélio M. de Oliveira; Ricardo M. Campello de Souza (CoRR, 2015)

Compactly Supported Wavelets Derived From Legendre Polynomials: Spherical Harmonic Wavelets. - M. M. S. Lira; Hélio M. de Oliveira; M. A. Carvalho Jr.; Ricardo M. Campello de Souza (CoRR, 2015)

Wavelets for Elliptical Waveguide Problems. - M. M. S. Lira; Hélio M. de Oliveira; Renato J. Cintra; Ricardo M. Campello de Souza (CoRR, 2015)

Fourier Codes and Hartley Codes. - Hélio M. de Oliveira; C. M. F. Barros; Ricardo M. Campello de Souza (CoRR, 2015)

A Factorization Scheme for Some Discrete Hartley Transform Matrices. - Hélio M. de Oliveira; Renato J. Cintra; Ricardo M. Campello de Souza (CoRR, 2015)

Multilayer Hadamard Decomposition of Discrete Hartley Transforms. - Hélio M. de Oliveira; Renato J. Cintra; Ricardo M. Campello de Souza (CoRR, 2015)

Spread-Spectrum Based on Finite Field Fourier Transforms. - Hélio M. de Oliveira; Joao Paulo C. L. Miranda; Ricardo M. Campello de Souza (CoRR, 2015)

A Flexible Implementation of a Matrix Laurent Series-Based 16-Point Fast Fourier and Hartley Transforms. - R. C. de Oliveira; Hélio M. de Oliveira; Ricardo M. Campello de Souza; E. J. P. Santos (CoRR, 2015)

Orthogonal Multilevel Spreading Sequence Design. - Hélio M. de Oliveira; Ricardo M. Campello de Souza (CoRR, 2015)

Radix-2 Fast Hartley Transform Revisited. - Hélio M. de Oliveira; Viviane L. Sousa; A. N. Helfarne; Ricardo M. Campello de Souza (CoRR, 2015)

Efficient Multiplex for Band-Limited Channels: Galois-Field Division Multiple Access. - Hélio M. de Oliveira; Ricardo M. Campello de Souza; A. N. Kauffman (CoRR, 2015)

A Matrix Laurent Series-based Fast Fourier Transform for Blocklengths N=4 (mod 8). - Hélio M. de Oliveira; Ricardo M. Campello de Souza; R. C. de Oliveira (CoRR, 2015)

Fast Finite Field Hartley Transforms Based on Hadamard Decomposition. - Hélio M. de Oliveira; R. G. F. Távora; Renato J. Cintra; Ricardo M. Campello de Souza (CoRR, 2015)

New Algorithms for Computing a Single Component of the Discrete Fourier Transform. - Gilson Jerônimo da Silva Jr.; Ricardo M. Campello de Souza; Hélio M. de Oliveira (CoRR, 2015)

Fourier Codes. - Ricardo M. Campello de Souza; Eduarda S. V. Freire 002; Hélio M. de Oliveira (CoRR, 2015)

The Hartley Transform in a Finite Field. - Ricardo M. Campello de Souza; Hélio M. de Oliveira; A. N. Kauffman (CoRR, 2015)

The Z Transform over Finite Fields. - Ricardo M. Campello de Souza; Hélio M. de Oliveira; Danilo Silva 001 (CoRR, 2015)

Cosine transforms over fields of characteristic 2. - Juliano B. Lima; Marco Barone; Ricardo M. Campello de Souza (Finite Fields Their Appl., 2016)

Closed-form Hermite-Gaussian-like number-theoretic transform eigenvectors. - Juliano B. Lima; Ricardo M. Campello de Souza (Signal Process., 2016)

Multiuser Communication Based on the DFT Eigenstructure. - Ricardo M. Campello de Souza; Hélio M. de Oliveira; Renato J. Cintra (CoRR, 2017)

Fractional Fourier, Hartley, Cosine and Sine Number-Theoretic Transforms Based on Matrix Functions. - Paulo Hugo E. S. Lima; Juliano B. Lima; Ricardo M. Campello de Souza (Circuits Syst. Signal Process., 2017)

Cosine transforms over fields of characteristic 2: Fast computation and application to image encryption. - Juliano B. Lima; Edmar S. da Silva; Ricardo M. Campello de Souza (Signal Process. Image Commun., 2017)

Meta-Fibonacci Codes: Efficient Universal Coding of Natural Numbers. - Bruno Tenório Ávila; Ricardo M. Campello de Souza (IEEE Trans. Inf. Theory, 2017)

Computation of an eigendecomposition-based discrete fractional Fourier transform with reduced arithmetic complexity. - José R. de Oliveira-Neto; Juliano B. Lima; Gilson Jerônimo da Silva Jr.; Ricardo M. Campello de Souza (Signal Process., 2019)

Tangent Function and Chebyshev-Like Rational Maps Over Finite Fields. - Juliano B. Lima; Ricardo M. Campello de Souza (IEEE Trans. Circuits Syst. II Express Briefs, 2020)

A Novel Approach for Defining a Hilbert Number Transform. - Juliano B. Lima; Marcos A. A. Gondim; Ricardo M. Campello de Souza (Circuits Syst. Signal Process., 2022)