15 citations · 38 across the 11 of their papers we have counts for
6 papers · 1 filter
Gröbner bases and cocyclic Hadamard matrices
V. Álvarez, J. A. Armario, R. M. Falcón +2
Hadamard ideals were introduced in 2006 as a set of nonlinear polynomial equations whose zeros are uniquely related to Hadamard matrices with one or two circulant cores of a given…
Equivalences of -cocyclic Hadamard matrices
V. Alvarez, F. Gudiel, M. B. Guemes +2
One of the most promising structural approaches to resolving the Hadamard Conjecture uses the family of cocyclic matrices over . Two types of…
GA based robust blind digital watermarking
Víctor Álvarez, José-Andrés Armario, María-Dolores Frau +4
A genetic algorithm based robust blind digital watermarking scheme is presented. Starting from a binary image (the original watermark), a genetic algorithm is performed searching f…
Embedding cocyclic D-optimal designs in cocyclic Hadamard matrices
Víctor Álvarez, José-Andrés Armario, María-Dolores Frau +1
In this paper a method for embedding cocyclic submatrices with ``large'' determinants of orders 2t in certain cocyclic Hadamard matrices of orders 4t is described (t an odd integer…
Searching for partial Hadamard matrices
Víctor Álvarez, José-Andrés Armario, María-Dolores Frau +4
Three algorithms looking for pretty large partial Hadamard matrices are described. Here "large" means that hopefully about a third of a Hadamard matrix (which is the best asymptoti…
Some new operations on Zt x Z2,2-cocyclic Hadamard matrices
Victor Alvarez, Felix Gudiel, Maria Belen Guemes
Following the ideas of [AGG11] about Zt x Z2,2-cocyclic Hadamard matrices, we introduce the notion of diagram, which visually represents any set of coboundaries. Diagrams are a ver…