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Ara es mostren els items 17-36 de 68

    • Compression of the MoM matrix using macrobasis functions with a full-controlable accuracy 

      Tamayo Palau, José María; Heldring, Alexander; Rius Casals, Juan Manuel (EurAPP, 2009)
      Text en actes de congrés
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      A new accuracy-controlable method for compressing the MoM impedance matrix of an electromagnetic problem based on a basis change plus a truncation with a threshold is presented here. The idea is to switch to singular basis ...

    • Creació de recursos en línea per a l’autoaprenentage, foment de l’esperit crític i emprenedor i formació d’un comité d’avaluació externa en el màster MERIT 

      Pradell i Cara, Lluís; Cabrera-Bean, Margarita; Canal Bienzobas, Fernando; Cardama Aznar, Ángel; Gasull Llampallas, Antoni; González Arbesú, José María; Giró Nieto, Xavier; Heldring, Alexander; Herranz Luis, Jaime; Jofre Roca, Lluís; Mallorquí Franquet, Jordi Joan; Nadeu Camprubí, Climent; Olmos Bonafé, Juan José; Romeu Robert, Jordi; Rius Casals, Juan Manuel; Torres Torres, Francisco; Úbeda Farré, Eduard; Coderch Collell, Marcel; Kerans, Mary Ellen; Ros Giralt, Jordi; García, Antonio; González Font, Blanca; Guardiola Garcia, Marta; Hernández, Antoni; Melgarejo, Natali; Mestres, Albert (2009-02-12T10:25:51Z)
      Comunicació de congrés / Text en actes de congrés
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      El projecte es desenvolupa en el marc de la titulació oficial de màster MERIT del Departament de Teoria del Senyal i Comunicacions. El màster, orientat a la recerca i integrat dins del programa Erasmus Mundus, presenta ...

    • Discretization of the EFIE in Method of Moments without continuity of the normal current component across edges 

      Úbeda Farré, Eduard; Rius Casals, Juan Manuel; Heldring, Alexander (Institute of Electrical and Electronics Engineers (IEEE), 2013)
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      The discretization in Method of Moments (MoM) of the Electric-Field Integral Equation (EFIE) is traditionally carried out by preserving the continuity of the normal component in the expansion of the current across the ...

    • Edge diffraction computation using GRECO 

      Rius Casals, Juan Manuel; Carbo, Alex; Úbeda Farré, Eduard; Heldring, Alexander (Institute of Electrical and Electronics Engineers (IEEE), 2016)
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      This paper addresses two graphical processing approaches for computation of edge scattering with Physical Theory of Diffraction (PTD) high-frequency approximation. One is based on processing only a bitmap containing an ...

    • Efficient analysis of homogeneous dielectric and plasmonic media with integral equation MEI (IE-MEI) 

      Rius Casals, Juan Manuel; Planes Conangla, Gerard; Úbeda Farré, Eduard; Heldring, Alexander (Institute of Electrical and Electronics Engineers (IEEE), 2015)
      Comunicació de congrés
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      This paper revisits the IE-MEI method and proposes a new formulation for high-loss dielectric piecewise-homogeneous media. The aim of this work is to assess if the fast attenuation of fields in highly lossy media helps in ...

    • Efficient computation of the effect of wire ends in thin wire analysis 

      Heldring, Alexander; Úbeda Farré, Eduard; Rius Casals, Juan Manuel (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2006-10-31)
      Article
      Accés obert
      Computationally efficient algorithms are presented for the computation of the effect of flat wire ends (end caps) in the common thin wire model. A uniform charge distribution over the surface of the end cap is assumed, and ...

    • Error bound of the multilevel adaptive cross approximation (MLACA) 

      Chen, Xinlei; Gu, Changqing; Heldring, Alexander; Li, Zhuo; Cao, Qunsheng (2016-01)
      Article
      Accés obert
      An error bound of the multilevel adaptive cross approximation (MLACA 1, which is a multilevel version of the adaptive cross approximation-singular value decomposition (ACA-SVD), is rigorously derived. For compressing an ...

    • Fast analysis and optimization of sparsely distributed partial modification problems 

      Fang, Xiaoxing; Heldring, Alexander; Rius Casals, Juan Manuel; Cao, Qunsheng (Institute of Electrical and Electronics Engineers (IEEE), 2022-08)
      Article
      Accés obert
      This article addresses the efficient numerical analysis of sparsely distributed small modifications in a large structure, that is, the sparsely distributed partial modification problem (SDPMP). A hierarchical matrix ...

    • Fast direct solution of method of moments linear system 

      Heldring, Alexander; Rius Casals, Juan Manuel; Tamayo Palau, José María; Parrón Granados, Josep; Úbeda Farré, Eduard (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2007-11)
      Article
      Accés obert
      A novel algorithm, the compressed block decomposition (CBD), is presented for highly accelerated direct (non iterative) method of moments (MoM) solution of electromagnetic scattering and radiation problems. The algorithm ...

    • Fast direct solution of the combined field integral equation 

      Heldring, Alexander; Tamayo Palau, José María; Rius Casals, Juan Manuel (2010)
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      The Method of Moments for electromagnetic scattering and radiation problems is often used in conjunction with the EFIE because the EFIE allows the analysis of open surfaces. For electrically large closed surfaces, the ...

    • Fast shadowing computation in physical optics surface 

      Rius Casals, Juan Manuel; Carbo, Alex; Úbeda Farré, Eduard; Heldring, Alexander (2013)
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      Accés restringit per política de l'editorial
      GRECO code has been updated by replacing the graphical processing technique for computation of Physical Optics surface integral by a hybrid CPU-graphical processing approach. The resulting code needs more CPU power for ...

    • Frequency extrapolation of IE-MEI linear system Coefficients in 2D 

      Rius Casals, Juan Manuel; Heldring, Alexander; Úbeda Farré, Eduard (Institute of Electrical and Electronics Engineers (IEEE), 2017)
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      The Integral Equation MEI (IE-MEI) method for the sparsification of Method of Moments linear system matrix is revisited here. It achieves cpu computation time and storage memory requirements of order O(N ) (for 2D perfectly ...

    • Geometric algebra formulation of the Calderon Projector 

      López Menchón, Héctor; Rius Casals, Juan Manuel; Úbeda Farré, Eduard; Heldring, Alexander (2019)
      Comunicació de congrés
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      Geometric Algebra provides a mathematical frame-work that allows to express many equations of physics in a more compact way [1]. It unifies the electric and the magnetic field in a single mathematical object: a multivector. ...

    • GRECO Code Rejuvenated: hybrid CPU-graphical processing 

      Rius Casals, Juan Manuel; Carbo, Alex; Úbeda Farré, Eduard; Heldring, Alexander (IEEE, 2013)
      Text en actes de congrés
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      GRECO code has been updated by replacing the graphical processing technique for computation of Physical Optics surface integral by a hybrid CPU-graphical processing approach. The resulting code needs more CPU power for ...

    • GRECO: 30 years of graphical processing techniques for RCS computation 

      Rius Casals, Juan Manuel; Úbeda Farré, Eduard; Heldring, Alexander (2018)
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      This contribution to the special session in honor of Prof. Rafael Gómez-Martín will address the 30 year development of graphical processing techniques (GRECO) for fast computation of Radar Cross Section (RCS) of ...

    • Grid design benchmark on sheets with nonzero thickness 

      Úbeda Farré, Eduard; Rius Casals, Juan Manuel; Heldring, Alexander; López Menchón, Héctor (Universitat Politècnica de Catalunya. Remote Sensing, Antennas, Microwaves and Superconductivity Group (CommSensLab), 2022)
      Text en actes de congrés
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      The conventional scattering analysis of perfectly conducting sheets ignores the scattering contribution of the rim. The so-called thin-surface scheme arises from the discretization of the Electric-field Integral Equation ...

    • Improvements in randomized matrix compression methods for numerical analysis of antennas and scatterers 

      López Menchón, Héctor; Heldring, Alexander; Úbeda Farré, Eduard; Rius Casals, Juan Manuel (Luis Landesa-Porras, 2023)
      Comunicació de congrés
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      We propose a randomized Pseudo Skeleton (or CUR) Approximation method to compress the H-matrices of linear systems that arise in the discretization of integral equations in electromagnetic scattering. This method is highly ...

    • Improving the accuracy of the adaptive cross approximation with a convergence criterion based on random sampling 

      Heldring, Alexander; Úbeda Farré, Eduard; Rius Casals, Juan Manuel (2020-07-27)
      Article
      Accés obert
      The accuracy of the Adaptive Cross Approximation (ACA) algorithm, a popular method for the compression of low rank matrix blocks in Method of Moment computations, is sometimes seriously compromised by unpredictable errors ...

    • Integral Equation MEI (IE-MEI) analysis of homogeneus dielectric and plasmonic media in 2D 

      Rius Casals, Juan Manuel; Planes Conangla, Gerard; Úbeda Farré, Eduard; Heldring, Alexander (2015)
      Text en actes de congrés
      Accés obert
      This paper revisits the IE-MEI method and proposes a new formulation for high-loss didectric piecewise-homogeneous media. The aim of this work is lo assess if the bigh localization of surface plasmon polarltons helps in ...

    • 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)
      Text en actes de congrés
      Accés restringit per política de l'editorial
      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 ...