1,721,014 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Symbolic-numeric implementation of the four potential method for calculating normal modes of square electromagnetic waveguide with rectangular insert
No full textIn this paper, the Maple computer algebra system is used to construct a symbolic-numeric implementation of the method for calculating normal modes of square closed waveguides in a vector formulation. The method earlier proposed by Malykh et al. [M.D. Malykh, L.A. Sevastianov, A.A. Tiutiunnik, N.E. Nikolaev. On the representation of electromagnetic fields in closed waveguides using four scalar potentials // Journal of Electromagnetic Waves and Applications, 32 (7), 886-898 (2018)] will be referred to as the method of four potentials. The Maple system is used at all stages of treating the system of differential equations for four potentials: the generation of the Galerkin basis, the substitution of approximate solution into the system under study, the formulation of a computational problem, and its approximate solution. The paper presents the results of the verification method. © 2019 Author(s)
Variations on the Author
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
О применении метода М.Н. Лагутинского к интегрированию дифференциальных уравнений 1-го порядка. Часть 1. Отыскание алгебраических интегралов
Get PDFThe method of M.N. Lagutinski (1871-1915) allows to find rational integrals and Darboux polynomials for given differential ring and thus can be used for integration of ordinary differential equations in symbolic form. A realization of Lagutinski method was made under free opensource mathematics software system Sage and will be presented in this article with application for symbolic integration of 1st order differential equations. In the first part of the article basic concepts of the Lagutinski method is briefly stated for polynomials rings. Then this method is applied to search of algebraic integrated curves for given ordinary differential equations of the form d + d withМетод М.Н. Лагутинского (1871-1915) позволяет искать рациональные интегралы и многочлены Дарбу заданного дифференциального кольца и поэтому может быть использован при интегрировании обыкновенных дифференциальных уравнений в символьном виде. В настоящей статье представлена реализация метода Лагутинского, выполненная в свободной системой компьютерной алгебры Sage, и дан обзор её возможностей по интегрированию дифференциальных уравнений 1-го порядка в символьном виде. В первой части статьи кратко изложены основные понятия метода Лагутинского для полиномиальных колец, затем этот метод приложен к отысканию алгебраических интегральных кривых дифференциальных уравнений вида d +
О трансцендентных функциях, возникающих при интегрировании дифференциальных уравнений в конечном виде
No full textПредложен вариант такой теории Галуа для систем обыкновенных дифференциальных уравнений, в которой не фиксируется список допустимых трансцендентных операций. Доказана теорема, согласно которой поле интегралов системы дифференциальных уравнений эквивалентно полю рациональных функций на гиперповерхности, допускающей непрерывную группу бирациональных автоморфизмов, размерность которой совпадает с числом алгебраически независимых трансцендент, вводимых интегрированием системы. Предложенное построение является развитием алгебраических идей, изложенных Полем Пенлеве в его Стокгольмских лекциях. Библ. -- 34 назв
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Normal modes of a waveguide as eigenvectors of a self-adjoint operator pencil
Get PDFA waveguide with a constant, simply connected section is considered under the condition that the substance filling the waveguide is characterized by permittivity and permeability that vary smoothly over the section ?, but are constant along the waveguide axis. Ideal conductivity conditions are assumed on the walls of the waveguide. On the basis of the previously found representation of the electromagnetic field in such a waveguide using 4 scalar functions, namely, two electric and two magnetic potentials, Maxwell’s equations are rewritten with respect to the potentials and longitudinal components of the field. It appears possible to exclude potentials from this system and arrive at a pair of integro-differential equations for longitudinal components alone that split into two uncoupled wave equations in the optically homogeneous case. In an optically inhomogeneous case, this approach reduces the problem of finding the normal modes of a waveguide to studying the spectrum of a quadratic self-adjoint operator pencil.В статье рассматривается волновод постоянного односвязного сечения при условии, что заполняющее волновод вещество характеризуется диэлектрической и магнитной проницаемостями, меняющимися плавно на сечении ?, но постоянными вдоль оси волновода. На стенках волновода взяты условия идеальной проводимости. На основе найденного ранее представления электромагнитного поля в таком волноводе при помощи четырёх скалярных функций - двух электрических и двух магнитных потенциалов - уравнения Максвелла записаны относительно потенциалов и продольных компонент поля. Из этой системы удаётся исключить потенциалы и записать пару интегро-дифференциальных уравнений относительно одних продольных компонент, расщепляющихся на два несвязанных волновых уравнения в оптически однородном случае. В оптически неоднородном случае этот подход позволяет свести задачу об отыскании нормальных мод волновода к исследованию спектра квадратичного самосопряжённого операторного пучка
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