Now showing items 48-67 of 184

    • Efficient rigorous numerics for higher-dimensional PDEs via one-dimensional estimates 

      Gameiro M.; Lessard J.-P. (SIAM Journal on Numerical Analysis, 2013-12-31)
      We present an efficient rigorous computational method which is an extension of the work Analytic Estimates and Rigorous Continuation for Equilibria of Higher-Dimensional PDEs (M. Gameiro and J.-P. Lessard, J. Differential ...
    • Efficient Rotating Frame Simulation in Turbomachinery 

      Remaki L.; Ramezani A.; Blanco J.M.; Antolin J.I. (Proceedings of ASME Turbo Expo 2014: Turbine Technical Conference and Exposition; Dusseldorf, Germany, June 16-20 2014", 2014-12-31)
      This paper deals with the simulation of steady flows in tur- bomachinery. Two approaches are proposed, the first one is the classical multiple-rotating frame method (MRF) by multi- zone approach where the different zones ...
    • Energy-norm-based and goal-oriented automatic hp adaptivity for electromagnetics: Application to waveguide Discontinuities 

      Garcia-Castillo L.E.; Pardo D.; Demkowicz L.F. (IEEE Transactions on Microwave Theory and Techniques, 2008-12-31)
      The finite-element method (FEM) enables the use of adapted meshes. The simultaneous combination of h (local variations in element size) and p (local variations in the polynomial order of approximation) refinements, i.e., ...
    • Enhanced variational image dehazing 

      Galdran A.; Vazquez-Corral J.; Pardo D.; Bertalmo M. (SIAM Journal on Imaging Sciences, 2015-12-31)
      Images obtained under adverse weather conditions, such as haze or fog, typically exhibit low contrast and faded colors, which may severely limit the visibility within the scene. Unveiling the image structure under the haze ...
    • Existence of secondary bifurcations or isolas for PDEs 

      Gameiro M.; Lessard J.-P. (Nonlinear Analysis, Theory, Methods and Applications, 2011-12-31)
      In this paper, we introduce a method to conclude about the existence of secondary bifurcations or isolas of steady state solutions for parameter dependent nonlinear partial differential equations. The technique combines ...
    • Explicit-in-Time Goal-Oriented Adaptivity 

      Muñoz-Matute J.; Calo V.M.; Pardo D.; Alberdi E.; Van der Zee K.G. (Computer Methods in Applied Mechanics and Engineering, 2019-04-15)
      Goal-oriented adaptivity is a powerful tool to accurately approximate physically relevant solution features for partial differential equations. In time dependent problems, we seek to represent the error in the quantity of ...
    • Explicit-in-Time Variational Formulations for Goal-Oriented Adaptivity 

      Muñoz-Matute J. (2019-10)
      Goal-Oriented Adaptivity (GOA) is a powerful tool to accurately approximate physically relevant features of the solution of Partial Differential Equations (PDEs). It delivers optimal grids to solve challenging engineering ...
    • Exponential decay of high-order spurious prolate spheroidal modes induced by a local approximate dtn exterior boundary condition 

      Barucq H.; Djellouli R.; Saint-Guirons A. (Progress In Electromagnetics Research B, 2012-12-31)
      We investigate analytically the asymptotic behavior of high-order spurious prolate spheroidal modes induced by a second-order local approximate DtN absorbing boundary condition (DtN2) when employed for solving high-frequency ...
    • Fast 2.5D Finite Element Simulations of Borehole Resistivity Measurements 

      Rodriguez-Rozas A.; Pardo D.; Torres-Verdín C. (Computational Geosciences, 2018-05-29)
      We develop a rapid 2.5-dimensional (2.5D) finite element method for simulation of borehole resistivity measurements in transversely isotropic (TI) media. The method combines arbitrary high-order $H^1$ - and $H$ (curl)-conforming ...
    • Fast inversion of logging-while-drilling resistivity measurements acquired in multiple wells 

      Bakr S. A.; Pardo D.; Torres-Verdín C. (Geophysics, 2016-10)
      This paper introduces a new method for the fast inversion of borehole resistivity measurements acquired in multiple wells using logging-while-drilling (LWD) instruments. There are two key novel contributions. First, we ...
    • Fast One-dimensional Finite Element Approximation of Geophysical Measurements 

      Shahriari M. (2018)
      There exist a wide variety of geophysical prospection methods. In this work, we focus on resistivity methods. We categorize these resistivity prospection methods according to their acquisition location as (a) on the surface, ...
    • Fast simulation of through-casing resistivity measurements using semi-analytical asymptotic models. Part 1: Accuracy study 

      Erdozain A.; Peron V.; Pardo D. (EAGE Workshop on High Performance Computing for Upstream 2014, 2014-12-31)
      When trying to obtain a better characterization of the Earth's subsurface, it is common to use borehole through-casing resistivity measurements. It is also common for the wells to be surrounded by a metal casing to protect ...
    • A FEniCS-HPC framework for multi-compartment Bloch-Torrey models 

      Nguyen D.; Jansson J.; Hoffman J. (Proceesings of ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering, 2016-11-30)
      In diffusion nuclear magnetic resonance (NMR) and diffusion magnetic resonance imaging (MRI), the multi-compartment Bloch-Torrey equation plays an important role in probing the diffusion characteristics from a nanometer ...
    • FEniCS-HPC: Automated predictive high-performance finite element computing with applications in aerodynamics 

      Hoffman J.; Jansson J.; Jansson N. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2016-01-01)
      Developing multiphysics finite element methods (FEM) and scalable HPC implementations can be very challenging in terms of software complexity and performance, even more so with the addition of goal-oriented adaptive mesh ...
    • Finite element approximation of electromagnetic fields using nonfitting meshes for Geophysics 

      Chaumont-Frelet T.; Nicaise S.; Pardo D. (SIAM Journal on Numerical Analysis, 2018-07)
      We analyze the use of nonfitting meshes for simulating the propagation of electromagnetic waves inside the earth with applications to borehole logging. We avoid the use of parameter homogenization and employ standard edge ...
    • Finite Element Simulations of Logging-While-Drilling and Extra-Deep Azimuthal Resistivity Measurements using Non-Fitting Grids 

      Chaumont-Frelet T.; Pardo D.; Rodriguez-Rozas A. (Computational Geosciences, 2018-04-27)
      We propose a discretization technique using non-fitting grids to simulate magnetic field-based resistivity logging measurements. Non-fitting grids are convenient because they are simpler to generate and handle than fitting ...
    • Finite Element Simulations of Two-phase Flow and Floating Bodies Using FEniCS-HPC 

      Moragues M.; Castanon D.; Degirmeci N.C.; Jansson J.; Nava V.; Krishnasamy E.; Hoffman J. (13th World Congress in Computational Mechanics WCCM, New York, USA, 2018-07)
      We present a variational multiscale stabilized finite element method to solve the variable density incompressible Navier-Stokes equations for the simulation of two-phase flow. We introduce a level-set method based on the ...
    • Forward-in-Time Goal-Oriented Adaptivity 

      Muñoz-Matute J.; Pardo D.; Calo V.M.; Alberdi E. (International Journal for Numerical Methods in Engineering, 2019-03)
      In goal-oriented adaptive algorithms for partial differential equations, we adapt the finite element mesh in order to reduce the error of the solution in some quantity of interest. In time-dependent problems, this adaptive ...
    • Fourier finite element modeling of light emission in waveguides: 2.5-dimensional FEM approach 

      Ou Y.; Pardo D.; Chen Y. (Optics Express, 2015-12-31)
      We present a Fourier finite element modeling of light emission of dipolar emitters coupled to infinitely long waveguides. Due to the translational symmetry, the three-dimensional (3D) coupled waveguide-emitter system can ...
    • Fractional Laguerre spectral methods and their applications to fractional differential equations on unbounded domain 

      Aboelenen T.; Bakr S.A.; El-Hawary H.M. (International Journal of Computer Mathematics, 2015-12-31)
      In this article, we first introduce a singular fractional Sturm-Liouville problem (SFSLP) on unbounded domain. The associated fractional differential operator is both Weyl and Caputo type. The properties of spectral data ...