1,721,039 research outputs found
A Bianisotropic FIT Formulation over Polyhedral Grids for Metamaterial Modeling
No full textModeling bianisotropic constitutive equations, i.e. magnetoelectric coupling, in electromagnetics simulation is increasingly important, in particular in
metamaterials applications. This paper introduces for the first time such constitutive relationships in the framework of FIT and, furthermore, does so by allowing full generality in the discretization through arbitrary polyhedral grids. The resulting formulation is consistent, stable and preserves the thermodynamic properties of the bianisotropic constitutive equations thanks to the energetic approach used to construct the interpolating functions
Base functions and discrete constitutive relations for staggered polyhedral grids
No full textAn electromagnetic problem can be discretized on a pair of interlocked primal-dual grids according to discrete geometric approaches like the Finite Integration Technique (FIT) or the Cell Method (CM). The critical aspect is however the construction of the discrete counterparts of the constitutive relations assuring stability and consistency of the overall discrete system of algebraic equations. Initially only orthogonal Cartesian grids where considered; more recently primal grids of tetrahedra and oblique prisms with triangular base can be handled. With this paper a novel set of edge and face vector functions for general polyhedral primal grids is presented, complying with precise specifications which allow to construct stable and consistent discrete constitutive equations in the framework of an energetic approach
Convergence of Electromagnetic Problems Modelled by Discrete Geometric Approach
No full textThis paper starts from the spatial discretization of an electromagnetic
problem over pairs of oriented grids, one dual of the other, according to the so
called Discrete Geometric Approach (DGA) to computational electromagnetism;
the Cell Method or the Finite Integration Technique are examples of such an approach.
The core of the work is providing for the first time a convergence analysis
when the discrete counter-parts of constitutive relations are computed by means of
an energetic framework
A FIT formulation of bianisotropic materials over polyhedral grids
No full textModeling bianisotropic constitutive equations, i.e., magnetoelectric coupling, in electromagnetics simulation is increasingly important, in particular in metamaterials applications. This paper introduces for the first time such constitutive relationships in the framework of finite integration technique and, furthermore, does so by allowing full generality in the discretization through arbitrary polyhedral grids. The resulting formulation is consistent, stable, and preserves the thermodynamic properties of the bianisotropic constitutive equations because of the energetic approach used to construct the interpolating functions
Picewise uniform bases and energetic approach for discrete constitutive matrices in electromagnetic problems
No full textIn the paper we introduce piecewise uniform edge and face vector functions on a simplicial primal
cell complex having geometric structure common to Whitney’s vector functions. We also introduce
piecewise uniform bases functions in the barycentric dual complex, where the analogous of Whitney’s
functions does not exist. By using these piecewise uniform bases functions and by exploiting an
energetic approach, we construct symmetric positive definite constitutive matrices for discrete Maxwell’s
equations. We also prove that these constitutive matrices are deeply related to those of the finite
elements with Whitney’s bases functions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Error Bounds for Discrete Geometric Approach
No full textElectromagnetic problems spatially discretized by the so called Discrete
Geometric Approach are considered, where Discrete Counterparts of Constitutive
Relations are discretized within an Energetic Approach. Pairs of oriented
dual grids are considered in which the primal grid is composed of (oblique) parallelepipeds,
(oblique) triangular prisms and tetrahedra and the dual grid is obtained
according to the barycentric subdivision. The focus of the work is the evaluation
of the constants bounding the approximation error of the electromagnetic field; the
novelty is that such constants will be expressed in terms of the geometrical details
of oriented dual grids. A numerical analysis will confirm the theory
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