1,721,240 research outputs found
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
Combined Spectral Methods to Study Complex Scattering Problems Formulated with the Wiener-Hopf Technique: the Semi-infinite Grounded Dielectric Slab problem
Full text linkIn this work we present a new combination of spectral methods that allows to study complex scattering problem in spectral domain containing abrupt discontinuities of materials. The method is applied to a formulation of problem given in terms of incomplete Wiener-Hopf (WH) equations, where, for incompleteness, we intend that some of the physical boundary conditions arising from abrupt discontinuities provide terms in the WH equations not directly related to the plus and minus unknowns of the problem. This is the case of the semi-infinite grounded dielectric slab problem where the semi-infiniteness geometry of the material provide such situation. This problem is of great interest in antennas and propagation community and studies are proposed in different papers with different methods; see references in [1]. The WH incomplete equations are obtained as in [1] starting from the application of unilateral Laplace transform to wave equations defined in three different sub-regions, see Fig. 1
Modified Bresler-Marcuvitz Transverse Equation Theory for Wedge Shaped Regions to derive Generalized Wiener-Hopf Equations
Full text linkIn this work, we present a novel and general mathematical technique to get Generalized Wiener-Hopf Equations (GWHEs) in angular regions filled by an arbitrary linear medium and with arbitrary boundary conditions [1]-[2]. We first extend the transverse equation theory developed in [3] by Bresler and Marcuvitz for stratified media. We develop the theory for angular regions in electromagnetics using oblique Cartesian coordinates, starting from Maxwell's equations. It yields a matrix differential problem of first order (1) whose unknowns are the field component ψt tangent to the faces of the angular regions (i.e. the field components continuous on the boundaries)
The Wiener-Hopf Theory for the Scattering by an Impenetrable Polygonal Structure
Full text linkThe Generalized Wiener-Hopf technique and the associated Fredholm factorization method constitute powerful tools that allow to study in quasi-analytical form the diffraction by complex structures with edges. A characteristic of this technique is the possibility to break down the complexity of the diffraction problem into different homogeneous canonical subregions where the WH functional equations and their associated integral representations of Fredholm kind are deduced. The mathematical-physical model is comprehensive and it allows spectral interpretation. In this paper we consider a novel canonical scattering problem: the three face impenetrable polygon
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Wiener-Hopf Solution of Diffraction by a PEC Wedge in Anisotropic Media
Full text linkIn this work we present our recent work on novel Wiener-Hopf(WH) formulation for the analysis and the study of scattering of wedges [1] immersed in complex materials [2-3]. We start from an original study of the perfect electrically conducting (PEC) wedge immersed in uniaxial (εx=εy≠εz,μx=μy≠μz) and biaxial (all different εi, μi=x,y,z) media illuminated by plane waves, where the wedge has an aperture angle of 2π-2γ. The uniaxial case has been studied by Felsen in [4], however generalization and exploitation of this case has not been further carried out in literature
An Application of Angular Network Equations: Exact Solution of the PEC Wedge in Biaxial Media
Full text linkThe Generalized Wiener Hopf Equations are deduced for a PEC wedge immersed in an anisotropic medium starting from angular network equations. In the case of biaxial medium the Wiener-Hopf model is reduced to Classical Wiener-Hopf Equations that can be solved resorting to exact factorization. The spectral solution allows asymptotic estimates of far-field components in the case of plane wave illumination
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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