1,721,012 research outputs found
About asymptotic relations of Sobolev-type orthogonal systems
No full textLa presente monografía está basada en el artículo Relative Asymptotics for Orthogonal Polynomials with a Sobolev Inner Product de Francisco Marcellán y Walter Van Assche. En este trabajo se propone estudiar y detallar las demostraciones dadas en el artículo de los teoremas que establecen la relación asintótica entre un sistema ortogonal de polinomios con respecto a un producto interno tipo Sóbolev y un sistema ortogonal de polinomios con respecto a una medida que pertenece a la clase de Nevai M(0,1).This monograph is based on the article "Relative Asymptotics for Orthogonal Polynomials with a Sobolev Inner Product" by Francisco Marcellán and Walter Van Assche. The goal of this work is to study and detail the proofs given in the article of the theorems that establish the asymptotic relation between a system of orthogonal polynomials respecting to a Sobolev-type inner product and a system of orthogonal polynomials respecting to a Nevai's class M(0,1) measure
On a Problem of Koornwinder
No full textIn this note we solve a problem about the rational representability of hypergeometric terms which represent hypergeometric sums. This problem was proposed by Koornwinder in Koornwinder, T. H.: Hypergeometric series evaluation by Zeilberger's algorithm. In: Open Problems, ed. by Walter van Assche. J. of Comput. and Appl. Math.48, 1993, 225--243
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
Entropy of Hermite polynomials with application to the harmonic oscillator
No full textWe analyse the entropy of Hermite polynomials and orthogonal polynomials for the Freud weights w(x)=exp(-|x| )onR and show how these entropies are related to information entropy of the one-dimensional harmonic oscillator. The physical interest in such entropies comes from a stronger version of the Heisenberg uncertainty principle, due to Bialynicki-Birula and Mycielski, which is expressed as a lower bound for the sum of the information entropies of a quantum-mechanical system in the position space and in the momentum space. 1 The information entropies of the harmonic oscillator The Schrodinger equation in D dimensions is given by 2 # + V # = E#, where the potential V and the wave function # are functions of x =(x 1 ,...,x D)a nd E is the energy. The wave function # is normalized in such a way that #(x)=|#(x)| is a probability density in position space. If #(p) is the Fourier transform of the wave function #, then by the Plancherel formula #(p)=| #(p)| is also a probability density, but now in the momentum space. The information entropy for the quantummechanical system with potential V is then given by #(x)log#(x) dx # The author is a Senior Research Associate of the Belgian National Fund for Scientific Research (NFWO). This work is supported by INTAS project 93-219. 1991 Mathematics Subject Classification : 33C45
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
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
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