1,720,964 research outputs found
The quadruple planar bubble enclosing equal areas is symmetric
Full text linkIn this paper we make the final step in finding the optimal way to enclose and separate four planar regions with equal area. In Paolini and Tamagnini (ESAIM COCV 24(3):1303–1331, 2018) the graph-topology of the optimal cluster was found reducing the set of candidates to a one-parameter family of different clusters. With a simple argument we show that the minimal set has a further symmetry and hence is uniquely determined up to isometries
Approximation of functionals depending on jumps by elliptic functionals via G-convergence.
No full textOn a relation between stochastic integration and geometric measure theory
No full textTwo problems are addressed for the path of certain stochastic processes:
a) do they define currents? b) are these currents of a classical
type? A general answer to question a) is given for processes like semimartingales
or with Lyons-Zheng structure. As to question b), it is shown
that Hoelder continuous paths with exponent
\gamma > 1/2 define integral flat
chains
A basic theory with predicates
No full textAbstract
In this work we present a foundational theory with a certain degree of self-description, in which different kinds of primitive concepts allow a formalization close to common usage and open to different engraftings. We also show the relative consistency of this theory., with respect to a fragment of the Zermelo-Fraenkel set theory, by building some models
Isoperimetric planar clusters with infinitely many regions
No full textIn this paper we study infinite isoperimetric clusters. An infinite cluster E in Rd is a sequence of disjoint measurable sets Ek C Rd, called regions of the cluster, k = 1, 2, 3, ... A natural question is the existence of a cluster E with given volumes ak > 0 of the regions Ek, having finite perimeter P(E), which is minimal among all the clusters with regions having the same volumes. We prove that such a cluster exists in the planar case d = 2, for any choice of the areas ak with Z 11ak < co. We also show the existence of a bounded minimizer with the property P(E) = Tl1( partial differential & SIM;E), where partial differential & SIM;E denotes the measure theoretic boundary of the cluster. Finally, we provide several examples of infinite isoperimetric clusters for anisotropic and fractional perimeters
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
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
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