Now showing items 1-9 of 9

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      A Heuristic Procedure with Guided Reproduction for Constructing Cocyclic Hadamard Matrices  [Presentation]

      Álvarez Solano, Víctor; Frau García, María Dolores; Osuna Lucena, Amparo (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 ...
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      A Mixed Heuristic for Generating Cocyclic Hadamard Matrices  [Article]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Osuna Lucena, Amparo (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 ...
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      ACS Searching for D4t-Hadamard Matrices  [Presentation]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Martín García, Elena; Osuna Lucena, Amparo (Springer, 2010)
      An Ant Colony System (ACS) looking for cocyclic Hadamard matrices over dihedral groups D4t is described. The underlying weighted graph consists of the rooted trees described in [1], whose vertices are certain subsets ...
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      Error correcting codes from quasi-Hadamard matrices  [Presentation]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Martín García, Elena; Osuna Lucena, Amparo (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 ...
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      GA Based Robust Blind Digital Watermarking  [Article]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Martín García, Elena; Osuna Lucena, Amparo (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, ...
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      Generating binary partial Hadamard matrices  [Article]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Osuna Lucena, Amparo (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)) ...
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      Generating partial Hadamard matrices as solutions to a Constraint Satisfaction Problem characterizing cliques  [Presentation]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Osuna Lucena, Amparo (2017-07)
      A procedure is described looking for partial Hadamard matrices, as cliques of a particular subgraph Gt of Ito’s Hadamard Graph Δ(4t) [9]. The key idea is translating the problem of extending a given clique Cm to a larger ...
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      Rooted Trees Searching for Cocyclic Hadamard Matrices over D4t  [Presentation]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix; Osuna Lucena, Amparo (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 ...
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      Searching for partial Hadamard matrices  [Presentation]

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Martín García, Elena; Osuna Lucena, Amparo (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. ...