1,720,962 research outputs found
Affine Minkowski valuations
Full text linkIn geometric valuation theory, well-known examples of Minkowski valuations intertwining the special linear group are defined by the difference operator, projection operator and the moment operator. While the difference and projection operator are translation invariant the moment operator is not. The former examples can be seen as maps with values in the set of convex bodies in the first and the (n-1)-th exterior power of R^n respectively. By a result of Monika Ludwig the difference operator and the projection operator are the only continuous, translation invariant Minkowski valuations with their corresponding codomain that commute with the special linear group. We ask whether there is also a Minkowski valuation satisfying all of these properties but whose codomain is the set of convex bodies in the k-th exterior power of R^n for 1 < k < n. We give an answer to a more general question. We prove that for any finite-dimensional irreducible SL(n)-representation W such a Minkowski valuation with values in the set of convex bodies in W exists if and only if W equals the set of real numbers, the first or the (n-1)-th exterior power of R^n. Finally, we give some new examples satisfying all properties mentioned above but translation invariance. If n < 4 we show that there is a continuous and SL(n) equivariant Minkowski valuation defined on the set of convex bodies containing the origin in its interior with values in the set of convex bodies in W, for any finite-dimensional SL(n)-representation W. One of these examples is a generalization of the moment operator. The existence of a Busemann-Petty type inequality for the generalized moment operator is discussed
Quasianalyticity, uncertainty, and integral transforms on higher grassmannians
Full text linkWe investigate the support of a distribution on the real grassmannian
whose spectrum, namely its nontrivial -components, is restricted to a subset of all -types. We prove that unless is co-sparse, cannot be
supported at a point. We utilize this uncertainty principle to prove that if
, then the cosine transform of a distribution on the
grassmannian cannot be supported inside any single open Schubert cell
. The same holds for certain more general -cosine transforms
and for the Radon transform between grassmannians, and more generally for
various -modules. These results are then applied to
convex geometry and geometric tomography, where sharper versions of the
Aleksandrov projection theorem, Funk section theorem, and Klain's and
Schneider's injectivity theorems for convex valuations are obtained.Comment: Fixed a gap found by the referee (with the consequence that a weaker
notion of quasianalyticity is now used), some improvements to exposition
following the referee's suggestion
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
The Fourier transform on valuations is the Fourier transform
Full text linkAlesker has proved the existence of a remarkable isomorphism of the space of
translation-invariant smooth valuations that has the same functorial properties
as the classical Fourier transform. In this paper, we show how to directly
describe this isomorphism in terms of the Fourier transform on functions. As a
consequence, we obtain simple proofs of the main properties of the
Alesker--Fourier transform. One of these properties was previously only
conjectured by Alesker and is proved here for the first time.Comment: 32 page
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Full text linkWe 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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