Listar Computational Mathematics (CM) por fecha de publicación
Mostrando ítems 120 de 241

Sensitivity study of boreholetosurface and crosswell electromagnetic measurements acquired with energized steel casing to water displacement in hydrocarbonbearing layers
(20081231)We study the theoretical response of electromagnetically energized steel casing in the presence of subsurface variations of electrical resistivity. Casing is energized with a finitesize solenoid antenna located along the ... 
Energynormbased and goaloriented automatic hp adaptivity for electromagnetics: Application to waveguide Discontinuities
(20081231)The finiteelement 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., ... 
Simulation of DC duallaterolog measurements in complex formations: A Fourierseries approach with nonorthogonal coordinates and selfadapting finite elements
(20091231)Dual laterolog (DLL) makes use of a galvanic conduction principle to focus electrical currents into rock formations, thereby minimizing shoulder and borehole effects in the measurement of formation resistivity. The tool ... 
Performance of a multifrontal parallel direct solver for hpfinite element method
(20091231)In this paper we present the performance of our parallel multifrontal direct solver when applied to solve linear systems of equations resulting from discretizations of a hp Finite Element Method (hpFEM). The hpFEM ... 
On global and local mesh refinements by a generalized conforming bisection algorithm
(20101231)We examine a generalized conforming bisection (GCB)algorithm which allows both global and local nested refinements of the triangulations without generating hanging nodes. It is based on the notion of a mesh density function ... 
Arithmetic method of doubleinjectionelectrode model for resistivity measurement through metal casing
(20101231)Throughcasing resistivity (TCR) measurement instruments such as Cased Hole Formation Resistivity are extensively used for the dynamic monitoring of oil reservoirs during the production phase in oil wells to evaluate the ... 
Highfrequency analysis of the efficiency of a local approximate DtN2 boundary condition for prolate spheroidalshaped boundaries
(20101231)The performance of the secondorder local approximate DtN boundary condition suggested in [4] is investigated analytically when employed for solving highfrequency exterior Helmholtz problems with elongated scatterers. ... 
New post processing method for interpretation of through casing resistivity (TCR) measurements
(201103)We propose a new iterative method for post processing through casing resistivity (TCR) measurements. This method can be seen as a correction or extension of Kaufman´s theory to more complex scenarios, in which the casing ... 
Compensation effect analysis in DIE method for throughcasing measuring formation resistivity
(201108)The measuring technique based on DoubleInjectionElectrodes (DIE) and its compensation arithmetic method have been proven to be very useful for eliminating the errors caused by electrodescale mechanical tolerances in ... 
Modeling of bone conduction of sound in the human head using hpfinite elements: Code design and verification
(20111231)We focus on the development of a reliable numerical model for investigating the boneconduction of sound in the human head. The main challenge of the problem is the lack of fundamental knowledge regarding the transmission ... 
Simulation of marine controlled source electromagnetic measurements using a parallel fourier hpfinite element method
(20111231)We introduce a new numerical method to simulate geophysical marine controlled source electromagnetic (CSEM) measurements for the case of 2D structures and finite 3D sources of electromagnetic (EM) excitation. The method ... 
Rigorous computation of smooth branches of equilibria for the three dimensional CahnHilliard equation
(20111231)In this paper, we propose a new general method to compute rigorously global smooth branches of equilibria of higherdimensional partial differential equations. The theoretical framework is based on a combination of the ... 
Rigorous numerics for symmetric connecting orbits: Even homoclinics of the GrayScott equation
(20111231)In this paper we propose a rigorous numerical technique for the computation of symmetric connecting orbits for ordinary differential equations. The idea is to solve a projected boundary value problem (BVP) in a function ... 
On modifications of continuous and discrete maximum principles for reactiondiffusion problems
(20111231)In this work, we present and discuss some modifications, in the form of twosided estimation (and also for arbitrary source functions instead of usual signconditions), of continuous and discrete maximum principles for the ... 
Generalization of the Zlámal condition for simplicial finite elements in ℝ d
(20111231)The famous Zlámal's minimum angle condition has been widely used for construction of a regular family of triangulations (containing nondegenerating triangles) as well as in convergence proofs for the finite element method ... 
Existence of secondary bifurcations or isolas for PDEs
(20111231)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 ... 
On the regularization of the collision solutions of the onecenter problem with weak forces
(20111231)We study the possible regularization of collision solutions for one centre problems with a weak singularity. In the case of logarithmic singularities, we consider the method of regularization via smoothing of the potential. ... 
Nonobtuse local tetrahedral refinements towards a polygonal face/interface
(20111231)In this note we show how to generate and conformally refine nonobtuse tetrahedral meshes locally in the neighbourhood of a polygonal face or a polygonal interior interface of a threedimensional domain. The technique ... 
A Geometric Toolbox for Tetrahedral Finite Element Partitions
(20111231)In this work we present a survey of some geometric results on tetrahedral partitions and their refinements in a unified manner. They can be used for mesh generation and adaptivity in practical calculations by the finite ... 
Computational fixedpoint theory for differential delay equations with multiple time lags
(20121231)We introduce a general computational fixedpoint method to prove existence of periodic solutions of differential delay equations with multiple time lags. The idea of such a method is to compute numerical approximations of ...