Browsing Computational Mathematics (CM) by Issue Date
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Sensitivity study of boreholetosurface and crosswell electromagnetic measurements acquired with energized steel casing to water displacement in hydrocarbonbearing layers
(Geophysics, 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
(IEEE Transactions on Microwave Theory and Techniques, 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
(Geophysics, 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
(Proceedings of the IASTED International Conference on Advances in Computer Science and Engineering, ACSE 2009, 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 ... 
Highfrequency analysis of the efficiency of a local approximate DtN2 boundary condition for prolate spheroidalshaped boundaries
(Wave Motion, 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. ... 
Arithmetic method of doubleinjectionelectrode model for resistivity measurement through metal casing
(IEEE Transactions on Geoscience and Remote Sensing, 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 ... 
On global and local mesh refinements by a generalized conforming bisection algorithm
(Journal of Computational and Applied Mathematics, 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 ... 
Simulation of marine controlled source electromagnetic measurements using a parallel fourier hpfinite element method
(Computational Geosciences, 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 numerics for symmetric connecting orbits: Even homoclinics of the GrayScott equation
(SIAM Journal on Mathematical Analysis, 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
(Advances in Applied Mathematics and Mechanics, 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 ... 
Nonobtuse local tetrahedral refinements towards a polygonal face/interface
(Applied Mathematics Letters, 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 ... 
Generalization of the Zlámal condition for simplicial finite elements in ℝ d
(Applications of Mathematics, 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 ... 
On the regularization of the collision solutions of the onecenter problem with weak forces
(Discrete and Continuous Dynamical Systems, 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. ... 
A Geometric Toolbox for Tetrahedral Finite Element Partitions
(Efficient Preconditioned Solution Methods for Elliptic Partial Differential Equations, 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 ... 
Existence of secondary bifurcations or isolas for PDEs
(Nonlinear Analysis, Theory, Methods and Applications, 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 ... 
Rigorous computation of smooth branches of equilibria for the three dimensional CahnHilliard equation
(Numerische Mathematik, 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 ... 
Modeling of bone conduction of sound in the human head using hpfinite elements: Code design and verification
(Computer Methods in Applied Mechanics and Engineering, 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 ... 
Exponential decay of highorder spurious prolate spheroidal modes induced by a local approximate dtn exterior boundary condition
(Progress In Electromagnetics Research B, 20121231)We investigate analytically the asymptotic behavior of highorder spurious prolate spheroidal modes induced by a secondorder local approximate DtN absorbing boundary condition (DtN2) when employed for solving highfrequency ... 
The maximum angle condition is not necessary for convergence of the finite element method
(Numerische Mathematik, 20121231)We show that the famous maximum angle condition in the finite element analysis is not necessary to achieve the optimal convergence rate when simplicial finite elements are used to solve elliptic problems. This condition ... 
Intersecting invariant manifolds in spatial restricted threebody problems: Design and optimization of Earthtohalo transfers in the SunEarthMoon scenario
(Communications in Nonlinear Science and Numerical Simulation, 20121231)This work deals with the design of transfers connecting LEOs with halo orbits around libration points of the EarthMoon CRTBP using impulsive maneuvers. Exploiting the coupled circular restricted threebody problem ...