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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
Pentagram maps over rings, Grassmannians, and skewers
Get PDFThe pentagram map is a discrete dynamical system on planar polygons. By definition, the image of a polygon P under the pentagram map is the polygon P’ whose vertices are the intersection points of consecutive shortest diagonals of P. The pentagram map was introduced by R. Schwartz in 1992, and is now one of the most renowned discrete integrable systems. Several authors proposed generalizations of the pentagram map to other geometries, in particular to Grassmannians, where the role of points and lines is played by higher-dimensional subspaces, as well to skewer geometry, where both points and lines are affine lines in the three-dimensional Euclidean space. In the present paper, we develop a common framework for these kinds of generalizations. Specifically, we show that those maps can be viewed as pentagram maps in the projective plane over an appropriate ring. In general, those rings need not be division rings or commutative. We show that the Grassmannian pentagram map corresponds to the ring of matrices, while the skewer map is the pentagram map over the ring of dual numbers. Furthermore, we prove that the pentagram map remains integrable for any stably finite ground ring R
Pentagram maps over rings, Grassmannians, and skewers
Get PDFThe pentagram map is a discrete dynamical system on planar polygons. By
definition, the image of a polygon under the pentagram map is the polygon
whose vertices are the intersection points of consecutive shortest
diagonals of . The pentagram map was introduced by R. Schwartz in 1992, and
is now one of the most renowned discrete integrable systems. Several authors
proposed generalizations of the pentagram map to other geometries, in
particular to Grassmannians, where the role of points and lines is played by
higher-dimensional subspaces, as well to skewer geometry, where both points and
lines are affine lines in the three-dimensional Euclidean space. In the present
paper, we develop a common framework for these kinds of generalizations.
Specifically, we show that those maps can be viewed as pentagram maps in the
projective plane over an appropriate ring. In general, those rings need not be
division rings or commutative. We show that the Grassmannian pentagram map
corresponds to the ring of matrices, while the skewer map is the pentagram map
over the ring of dual numbers. Furthermore, we prove that the pentagram map
remains integrable for any stably finite ground ring .Comment: 27 pages, 1 figur
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
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Difference Operators and Pentagram Maps Over Rings
No full textThe pentagram map, first proposed by R. Schwartz in 1992, is a well studied discrete integrable system on real planar polygons. It has been reframed in the
language of difference operators using a known correspondence of certain degree
3 difference operators and polygons in P2. In this paper, we generalize the notion
of a projective space by describing one-dimensional “subspaces” in free modules
over stably finite rings. We then define polygons in such spaces and discuss how
these projective spaces relate to known objects, such as Grassmannians. With
these projective spaces, we generalize the correspondence of difference operators
and polygons by proving that there is a one-to-one correspondence between properly
bounded left (resp. right) difference operators, whose coefficients are from a
stably finite ring R, and polygons in a certain left (resp. right) projective space
over R. With this correspondence, we show that some known (and proposed)
generalizations of the pentagram map can be understood as the usual pentagram
map in a certain projective plane. Finally, we reframe these pentagram
maps in the language of difference operators, showing that the pentagram map on
pseudo-difference operators is a refactorization, and use this interpretation to find
invariants
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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