Now showing items 1-20 of 25

    • Article
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      A computational algebraic geometry approach to analyze pseudo-random sequences based on Latin squares 

      Falcón Ganfornina, Raúl Manuel; Álvarez Solano, Víctor; Gudiel Rodríguez, Félix (Springer, 2019)
      Latin squares are used as scramblers on symmetric-key algorithms that generate pseudo-random sequences of the same length. ...
    • Article
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      A Mixed Heuristic for Generating Cocyclic Hadamard Matrices 

      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 ...
    • Presentation
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      ACS Searching for D4t-Hadamard Matrices 

      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 ...
    • Presentation
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      Cocyclic Hadamard matrices over Latin rectangles 

      Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Güemes Alzaga, María Belén; Gudiel Rodríguez, Félix; Álvarez Solano, Víctor (2017)
    • Article
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      Cocyclic Hadamard matrices over Latin rectangles 

      Álvarez Solano, Víctor; Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén (Elsevier, 2019)
      In the literature, the theory of cocyclic Hadamard matrices has always been developed over finite groups. This paper ...
    • PhD Thesis
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      Descripción explícita de t-estructuras sobre espacios estratificados 

      Gudiel Rodríguez, Félix (2000)
      "En el presenta trabajo abordamos la cuestión anterior de la descripción de las categorías de haces perversos desde un ...
    • Article
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      Determinants of (–1,1)-matrices of the skew-symmetric type: a cocyclic approach 

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix (Walter de Gruyter GmbH, 2015)
      An n by n skew-symmetric type (−1, 1)-matrix K = [ki,j ] has 1’s on the main diagonal and ±1’s elsewhere with ki,j = ...
    • Article
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      Embedding cocylic D-optimal designs in cocylic Hadamard matrices 

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix (International Linear Algebra Society, 2012)
      A method for embedding cocyclic submatrices with “large” determinants of orders 2t in certain cocyclic Hadamard matrices ...
    • Article
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      Equivalences of Zt×Z22-cocyclic Hadamard matrices 

      Álvarez Solano, Víctor; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Horadam, K.J.; Rao, A. (Cornell University, 2015)
      One of the most promising structural approaches to resolving the Hadamard Conjecture uses the family of cocyclic matrices ...
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      Explicit models for perverse sheaves 

      Gudiel Rodríguez, Félix; Narváez Macarro, Luis (European Mathematical Society, 2003)
      We consider categories of generalized perverse sheaves, with relaxed constructibility conditions, by means of the process ...
    • Article
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      GA Based Robust Blind Digital Watermarking 

      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 ...
    • Article
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      Generating binary partial Hadamard matrices 

      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 ...
    • Presentation
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      Generating partial Hadamard matrices as solutions to a Constraint Satisfaction Problem characterizing cliques 

      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 ...
    • Presentation
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      Gröbner bases and cocyclic Hadamard matrices 

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Gudiel Rodríguez, Félix (2017-07)
    • Article
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      Gröbner bases and cocyclic Hadamard matrices 

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Falcón Ganfornina, Raúl Manuel; Frau García, María Dolores; Gudiel Rodríguez, Félix (Elsevier, 2018)
      Hadamard ideals were introduced in 2006 as a set of nonlin-ear polynomial equations whose zeros are uniquely related ...
    • Article
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      Hadamard Matrices with Cocyclic Core 

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Osuna Lucena, Amparo (MDPI, 2021)
      Since Horadam and de Launey introduced the cocyclic framework on combinatorial designs in the 1990s, it has revealed ...
    • PhD Thesis
    • Article
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      On Cocyclic Hadamard Matrices over Goethals-Seidel Loops 

      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 (MDPI, 2020)
      About twenty-five years ago, Horadam and de Launey introduced the cocyclic development of designs, from which the notion ...
    • Article
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      On D4t-Cocyclic Hadamard Matrices 

      Álvarez Solano, Víctor; Armario Sampalo, José Andrés; Frau García, María Dolores; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén; Osuna Lucena, Amparo (Wiley, 2016)
      In this paper, we describe some necessary and sufficient conditions for a set of coboundaries to yield a cocyclic Hadamard ...
    • Article
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      On ZZt × ZZ2 2-cocyclic Hadamard matrices 

      Álvarez Solano, Víctor; Gudiel Rodríguez, Félix; Güemes Alzaga, María Belén (Wiley, 2015)
      A characterization of ZZt × ZZ22 -cocyclic Hadamard matrices is described, de- pending on the notions of distributions, ...