1,720,971 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
Quasiconformal homogeneity and subgroups of the mapping class group
Get PDFIn the vein of Bonfert-Taylor, Bridgeman, Canary, and Taylor we introduce the
notion of quasiconformal homogeneity for closed oriented hyperbolic surfaces
restricted to subgroups of the mapping class group. We find uniform lower
bounds for the associated quasiconformal homogeneity constants across all
closed hyperbolic surfaces in several cases, including the Torelli group,
congruence subgroups, and pure cyclic subgroups. Further, we introduce a
counting argument providing a possible path to exploring a uniform lower bound
for the nonrestricted quasiconformal homogeneity constant across all closed
hyperbolic surfaces.Comment: 26 pages, 2 figures. This version incorporates referee's comments and
has been accepted for publication in the Michigan Mathematical Journa
Three perfect mapping class groups
Get PDFWe prove that the mapping class group of a surface obtained from removing a
Cantor set from either the 2-sphere, the plane, or the interior of the closed
2-disk has no proper countable-index subgroups. The proof is an application of
the automatic continuity of these groups, which was established by Mann. As
corollaries, we see that these groups do not contain any proper finite-index
subgroups and that each of these groups have trivial abelianization.Comment: v2: updated/corrected references, corrected abstract (which was
missing a key adjective), 6 page
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
Homeomorphism groups of telescoping 2-manifolds are strongly distorted
Get PDFBuilding on the work of Mann and Rafi, we introduce an expanded definition of a telescoping 2-manifold and proceed to study the homeomorphism group of a telescoping 2-manifold. Our main result shows that it is strongly distorted. We then give a simple description of its commutator subgroup, which is index one, two, or four depending on the topology of the manifold. Moreover, we show its commutator subgroup is uniformly perfect with commutator width at most two, and we give a family of uniform normal generators for its commutator subgroup. As a consequence of the latter result, we show that for an (orientable) telescoping 2-manifold, every (orientation-preserving) homeomorphism can be expressed as a product of at most 17 conjugate involutions. Finally, we provide analogous statements for mapping class groups.v2: incorporates referee\u27s comments; to appear in Groups Geom. Dy
Homeomorphism groups of self-similar 2-manifolds
Get PDFThe class of self-similar 2-manifolds consists of manifolds exhibiting a type
of homogeneity akin to the 2-sphere and the Cantor set, and includes both the
2-sphere and the 2-sphere with a Cantor set removed. This chapter aims to
provide a narrative thread between recent results on the structure of
homeomorphism groups/mapping class groups of self-similar 2-manifolds, and also
connections to classical structural results on the homeomorphism group of the
2-sphere and the Cantor set. In order to do this, we provide a survey of recent
results, an exposition on classical results about homeomorphism groups, provide
a treatment of the structure of stable sets, and prove
extensions/strengthenings of the recent results surveyed.
Of particular note, we establish the following theorems: (1) A
characterization of homeomorphisms of (orientable) perfectly self-similar
2-manifolds that normally generate the group of (orientation-preserving)
homeomorphisms -- a strengthening of a result of Malestein-Tao. (2) The
homeomorphism group of a perfectly self-similar 2-manifold is strongly
distorted -- an extension of a result of Calegari-Freedman for spheres. (3) The
homeomorphism group of a perfectly tame 2-manifold is Steinhaus, and hence has
the automatic continuity property -- an extension of a result of Mann in
dimension two -- providing the first examples of homeomorphism groups of
infinite-genus 2-manifolds with the Steinhaus property.Comment: To appear as Chapter 5 in the book In the tradition of Thurston, III
(ed. K. Ohshika, A. Papadopoulos), Springer, 2024. v4: Fixed typos. This
version was sent for publication. v3: incorporated the comments of the
anonymous reader. v2: corrected the proof of Proposition 6.12, updated
several references, and added hypotheses in several lemmas to guarantee the
existence of certain infinite product
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