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Ponencia
Error correcting codes from quasi-Hadamard matrices
(Springer, 2007)
Levenshtein described in [5] a method for constructing error correcting codes which meet the Plotkin bounds, provided suitable Ha- damard matrices exist. Uncertainty about the existence of Hadamard matrices on all orders ...
Artículo
On Cocyclic Hadamard Matrices over Goethals-Seidel Loops
(MDPI, 2020)
About twenty-five years ago, Horadam and de Launey introduced the cocyclic development of designs, from which the notion of cocyclic Hadamard matrices developed over a group was readily derived. Much more recently, it ...
Artículo
A Mixed Heuristic for Generating Cocyclic Hadamard Matrices
(Springer, 2018)
A way of generating cocyclic Hadamard matrices is described, which combines a new heuristic, coming from a novel notion of fitness, and a peculiar local search, defined as a constraint satisfaction problem. Calculations ...
Artículo
On D4t-Cocyclic Hadamard Matrices
(Wiley, 2016)
In this paper, we describe some necessary and sufficient conditions for a set of coboundaries to yield a cocyclic Hadamard matrix over the dihedral group D4t. Using this characterization, new classification results for ...
Ponencia
Searching for partial Hadamard matrices
(Universidade de Santiago de Compostela, Servicio de Publicaciones, 2010)
Three algorithms looking for pretty large partial Hadamard ma- trices are described. Here “large” means that hopefully about a third of a Hadamard matrix (which is the best asymptotic result known so far, [8]) is achieved. ...
Artículo
GA Based Robust Blind Digital Watermarking
(Elsevier, 2018)
A genetic algorithm based robust blind digital watermarking scheme is presented. The experimental results show that our scheme keeps invisibility, security and robustness more likely than other proposals in the literature, ...
Artículo
Generating binary partial Hadamard matrices
(Elsevier, 2019)
This paper deals with partial binary Hadamard matrices. Although there is a fast simple way to generate about a half (which is the best asymptotic bound known so far, see de Launey (2000) and de Launey and Gordon (2001)) ...
Artículo
Hadamard Matrices with Cocyclic Core
(MDPI, 2021)
Since Horadam and de Launey introduced the cocyclic framework on combinatorial designs in the 1990s, it has revealed itself as a powerful technique for looking for (cocyclic) Hadamard matrices. Ten years later, the series ...
Ponencia
A Heuristic Procedure with Guided Reproduction for Constructing Cocyclic Hadamard Matrices
(Springer, 2009)
A genetic algorithm for constructing cocyclic Hadamard matrices over a given group is described. The novelty of this algorithm is the guided heuristic procedure for reproduction, instead of the classical crossover and ...
Ponencia
Rooted Trees Searching for Cocyclic Hadamard Matrices over D4t
(Springer, 2009)
A new reduction on the size of the search space for cocyclic Hadamard matrices over dihedral groups D4t is described, in terms of the so called central distribution. This new search space adopt the form of a forest ...