Now showing items 1-20 of 25

  • A family of iterative methods that uses divided differences of first and second orders 

    Ezquerro, José Antonio; Grau Sánchez, Miguel; Hernández Verón, Miguel Angel; Noguera Batlle, Miquel (2015-11-01)
    Article
    Restricted access - publisher's policy
    The family of fourth-order Steffensen-type methods proposed by Zheng et al. (Appl. Math. Comput. 217, 9592-9597 (2011)) is extended to solve systems of nonlinear equations. This extension uses multidimensional divided ...
  • An improvement of Ostrowski root-finding method 

    Grau Sánchez, Miguel; Díaz Barrero, José Luis (2006-02)
    Article
    Restricted access - publisher's policy
    An improvement to the iterative method based on the Ostrowski one to compute nonlinear equation solutions, which increases the local order of convergence is suggested. The adaptation of a strategy presented here gives a ...
  • An iterative model for fractal antennas: application to the Sierpinski gasket antenna 

    Puente Baliarda, Carles; Borja Borau, M.Carmen; Navarro Rodero, Mònica; Romeu Robert, Jordi (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2000-05-31)
    Article
    Open Access
    A simple model that explains the behavior of the Sierpinski fractal antenna is presented. This model shows that the multiband behavior of the Sierpinski fractal antenna is a consequence of its fractal nature. The model is ...
  • Application of the multilevel decomposition algorithm to the frequency analysis of large microstrip antenna arrays 

    Parrón Granados, Josep; Rius Casals, Juan Manuel; Mosig, Juan R. (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2002-03-31)
    Article
    Open Access
    The application of integral equation methods based in the method of moments discretization to solve large antenna arrays is difficult due to the fact that the computational requirements increase rapidly with the number ...
  • Higher order multi-step iterative method for computing the numerical solution of systems of nonlinear equations: Application to nonlinear PDEs and ODEs 

    Ullah, Malik Zaka; Serra Capizzano, Stefano; Ahmad, Fayyaz; Alaidarous, Eman (2015-10-15)
    Article
    Restricted access - publisher's policy
    In the present study, we consider multi-step iterative method to solve systems of nonlinear equations. Since the Jacobian evaluation and its inversion are expensive, in order to achieve a better computational efficiency, ...
  • Higher order multi-step Jarratt-like method for solving systems of nonlinear equations: application to PDEs and ODEs 

    Ahmad, Fayyaz; Tohidi, Emran; Ullah, Malik Zaka; Carrasco, Juan A. (2015-08-01)
    Article
    Open Access
    This paper proposes a multi-step iterative method for solving systems of nonlinear equations with a local convergence order of 3m - 4, where in (>= 2) is the number of steps. The multi-step iterative method includes two ...
  • Hybrid sparse linear array synthesis applied to phased antenna arrays 

    Yepes, Leonardo Fabio; Covarrubias, David; Alonso, Miguel A.; Ferrús Ferré, Ramón Antonio (2014-01-16)
    Article
    Restricted access - publisher's policy
    In this letter, a new hybrid technique to synthesize sparse linear arrays is proposed. This technique is based on the combination of two methods. As a first method, a deterministic synthesis algorithm is used to resolve ...
  • Iterative method of moments solution of problems involving electrically large and concave geometries 

    Heldring, Alexander; Rius Casals, Juan Manuel; Úbeda Farré, Eduard (Institute of Electrical and Electronics Engineers (IEEE), 2013)
    Conference report
    Restricted access - publisher's policy
    This paper presents a study of the scaling with frequency (computational complexity) of preconditioned iterative solution, using the Multilevel Fast Multipole Method, of a class of radiation and scattering problems that ...
  • Maximum likelihood estimation of position in GNSS 

    Closas Gómez, Pau; Fernández Prades, Carlos; Fernández Rubio, Juan Antonio (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2007-05)
    Article
    Open Access
    In this letter, we obtain the Maximum Likelihood Estimator of position in the framework of Global Navigation Satellite Systems. This theoretical result is the basis of a completely different approach to the positioning ...
  • Method of moments enhancement technique for the analysis of Sierpinski pre-fractal antennas 

    Parrón Granados, Josep; Romeu Robert, Jordi; Rius Casals, Juan Manuel; Mosig, Juan R. (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2003-08-31)
    Article
    Open Access
    The numerical analysis of highly iterated Sierpinski microstrip patch antennas by method of moments (MoM) involves many tiny subdomain basis functions, resulting in a very large number of unknowns. The Sierpinski ...
  • Mètodes iteratius per a la resolució d'equacions no lineals 

    Fernández Sánchez, Marc (Universitat Politècnica de Catalunya, 2012-06-28)
    Master thesis (pre-Bologna period)
    Open Access
    El projecte consisteix en un estudi tant teòric com pràctic d'alguns dels mètodes iteratius sense memòria, emprats per la resolució d'equacions no lineals. Es plantegen i analitzen els cinc mètodes següents: Newton, Txebixev, ...
  • Un método simplificado de Newton para calcular la raíz cuadrada de una matriz real simétrica definida positiva 

    Mendoza Mexía, Alfredo; Gómez Aldama, Óscar Rubén (Universitat Politècnica de Catalunya, 2010)
    Article
    Open Access
  • ML estimator and hybrid beamformer for multipath and interference mitigation in GNSS receivers 

    Seco Granados, Gonzalo; Fernández Rubio, Juan Antonio; Fernández Prades, Carlos (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2005-05-31)
    Article
    Open Access
    This paper addresses the estimation of the code-phase(pseudorange) and the carrier-phase of the direct signal received from a direct-sequence spread-spectrum satellite transmitter. The signal is received by an antenna ...
  • Multiuser resource allocation optimization using bandwidth-power product in cognitive radio networks 

    Tachwali, Yahia; Lo, B.F.; Akyildiz, Ian; Agustí Comes, Ramon (2013-03)
    Article
    Restricted access - publisher's policy
    In this paper, the problem of resource allocation optimization is studied for a single-cell multiuser cognitive radio network in the presence of primary user networks. The spectral access of the cognitive radio network is ...
  • Nonlinear actuation model for lateral electrostatically-actuated DC-contact RF MEMS series switches. 

    Lázaro Guillén, Antoni; Girbau Sala, David; Pradell i Cara, Lluís; Nebot Serra, Àlvar (JOHN WILEY & SONS INC, 2007-06-01)
    Article
    Open Access
    In this work, a nonlinear model to predict actuation characteristics in lateral electrostatically-actuated DC-contact MEMS switches is proposed. In this case a parallel-plate approximation cannot be applied. The model ...
  • Practical algorithms for a family of waterfilling solutions 

    Pérez Palomar, Daniel; Rodríguez Fonollosa, Javier (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2005-02-28)
    Article
    Open Access
    Many engineering problems that can be formulated as constrained optimization problems result in solutions given by a waterfilling structure; the classical example is the capacity-achieving solution for a frequency-selective ...
  • Preconditioning techniques in the analysis of finite metamaterial slabs 

    Úbeda Farré, Eduard; Rius Casals, Juan Manuel; Romeu Robert, Jordi (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2006-01-31)
    Article
    Open Access
    In the method of moments (MoM) electric field integral equation (EFIE) analysis of slabs of metamaterials, we show that a left-preconditioning scheme by blocks gathering interactions between basis functions belonging to ...
  • Quantitative images of large biological bodies in microwave tomography by using numerical and real data 

    Mallorquí Franquet, Jordi Joan; Joachimowicz, N.; Broquetas Ibars, Antoni; Bolomey, J. C. (Jean-Charles) (IEE-INST ELEC ENG, 1996-11-01)
    Article
    Open Access
    A new inverse microwave imaging algorithm is presented which has the ability to obtain quantitative dielectric maps of large biological bodies. By using a priori information, obtained with a first order algorithm, the final ...
  • Second-order parameter estimation 

    Villares Piera, Nemesio J.; Vázquez Grau, Gregorio (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2005-07-31)
    Article
    Open Access
    This work provides a general framework for the design of second-order blind estimators without adopting any approximation about the observation statistics or the a priori distribution of the parameters. The proposed ...
  • Self-similar prefractal frequency selective surfaces for multiband and dual-polarized applications 

    Gianvittorio, John P.; Romeu Robert, Jordi; Blanch Boris, Sebastián; Rahmat-Samii, Yahya (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2003-01-31)
    Article
    Open Access
    Frequency-selective surfaces (FSS) that have been designed using the iterative techniques of fractals have been fabricated and measured. Fractals contain many scales of the starting geometry, each of which acts as a ...