1,721,100 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
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
(Z_2)^n-Superalgebra and (Z_2)^n-Supergeometry
No full textThe present thesis deals with a development of linear algebra, geometry and analysis based on (Z_2)^n-superalgebras: associative unital algebras which are (Z_2)^n-graded (for some natural number n) and graded-commutative, i.e., satisfying ab = (-1)^ ba, for all homogeneous elements a, b of respective degrees deg(a), deg(b) in (Z_2)^n, and denoting the usual scalar product. This generalization widens the range of applications of supergeometry to many mathematical structures -- the algebra of quaternions H and more generally Clifford algebras, Deligne algebra of superdifferential forms, higher vector bundles ... -- and appears also in physics -- for describing anyons, paraparticles -- proving its worth and relevance. In this dissertation, we first focus on (Z_2)^n-superalgebra theory: we define and characterize the notions of trace, determinant and Berezinian of matrices over graded-commutative algebras. Special attention is given to the case of Clifford algebras, where our study gives a new approach to treat the classical problem of finding a “good” determinant for matrices with non-commuting (quaternionic) entries. Further, we undertake the study of (Z_2)^n-graded differenital geometry. Privileging the ringed space approach, we define (smooth) (Z_2)^n-supermanifolds modeling their algebras of functions on the (Z_2)^n-commutative algebra of formal power series in graded variables, and develop the theory along the lines of supergeometry. Notable results are: the graded Berezinian and its cohomological interpretation (essential to establish integration theory); the theorem of morphism, which states that a morphism of (Z_2)^n-supermanifolds can be recovered from its coordinate expression; an analogous of Batchelor-Gawedzki theorem for (Z_2)^n-supermanifolds.La présente thèse porte sur le développement d’une théorie d’algèbre linéaire, de géométrie
et d’analyse basée sur les algèbres (Z_2)^n-graduées-commutatives, c.-à-d. des algèbres graduées associatives unitaires satisfaisant ab = (-1)^ ba, pour tout couple d’éléments homogènes a, b de degrés deg(a), deg(b) dans (Z_2)^n (où est le produit scalaire usuel). La valeur et pertinence de cette généralisation de la supergéométrie résulte de ses nombreuses applications: en mathématiques -- l’algèbre de Deligne des superformes différentielles, l’algèbre des quaternions H et les algèbres de Clifford en sont des exemples -- et même en physique -- paraparticules, anyons. Dans ce travail, nous traitons tout d’abord l’aspect algébrique: les notions de trace et de (super)déterminant pour des matrices à coefficients dans une algèbre graduée-commutative sont définies et étudiées (en particulier leurs charactérisations axiomatiques sont prouvées). Une attention particulière est porté au cas des algèbres de Clifford: ce point de vue ‘gradué’ fournit une nouvelle approche au problème classique de trouver un “bon” déterminant pour des matrices à coefficients non-commutatifs (quaternioniques). En outre, nous entreprenons l’étude de la géométrie différentielle (Z_2)^n-graduée. Privilégiant l’approche par les espaces annelés, les (Z_2)^n-supervariétés (lisses) sont définies en choisissant l’algèbre (Z_2)^n-commutative des séries formelles en variables graduées comme modèle pour leur faisceau de fonctions. La théorie est par la suite développée dans le sens de la supergéométrie. Les résultats les plus marquants ainsi obtenus sont: le Berezinien gradué et son interprétation cohomologique (essentielle pour établir une théorie de l’intégration); le théorème des morphismes, attestant qu’on peut rétablir un morphisme entre (Z_2)^n-supervariétés à partir de sa seule expression sur les coordonnées; l’analogue du théorème de Batchelor-Gawedzki pour les (Z_2)^n-supervariétés lisses
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