1,720,985 research outputs found
Cosystoles and cheeger constants of the simplex
No full textThe central interest of this thesis is to develop tools to get hands on the cosystolic
norm and the coboundary expansion of a cochain, values which are important to
determine the Cheeger constants of a simplicial complex. We develop some structural
theory about the cosystolic norm of a cochain, in which we, among other small
results, study an interesting connection between that norm and the hitting number
of a certain set system (see Chapter 2). In Chapter 3 we restrict our research to 1-
dimensional cosystoles of a simplex which are slightly easier to understand, so we
can provide more explicit results for that case, including the explicit determination
of the largest 1-dimensional cosystoles of a simplex and a rough insight, how all
1-cosystoles of a simplex in a certain dimension can be arranged in the so-called
cosystolic complex. Furthermore, we prove the strict inequality h1(D[n]) > n3
for the
case n = 16, which strengthens our conjecture that this strict inequality holds in general
if n is a power of 2. In Chapter 4 we study some alternative ways to generalize
the classical Cheeger constant which might be easier to access and prove that these
different constants equal for a large family of simplicial complexes. In Chapter 5 we
solve a beautiful combinatorial ordering problem, which is not directly related to the
main subject of this thesis but arose during considerations about that and should be
worth to be provided to the reader as well. In Appendix A we give an algorithm for
the exact calculation of the solutions of the ordering problem from Chapter 5
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
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
On subsets of finite abelian groups with no 3-term arithmetic progressions
No full textAbstractLet G be a finite abelian group of odd order and let D(G) denote the maximal cardinality of a subset A ⊂ G which does not contain a 3-term arithmetic progression. It is shown that D(Zk1 ⊕ ⋯ ⊕ Zkn) ⩽ 2((k1 ⋯ kn/n). Together with results of Szemerédi and Heath-Brown it implies that there exists a β > 0 such that D(G) = O(∥G∥/(log ∥G∥)β) for all G
A geometric construction of a superconcentrator of depth 2
No full textAbstractWe construct an N-superconcentrator of depth 2, with 3 N32+O(N1712) edges, by essentially duplicating the lines vs. points incidence graph of a projective plane. The validity of the construction rests mainly on the following theorem: If A and B are sets of points in a linear space such that ⋎A⋎=⋎B⋎=n and A∪B is not collinear, then there are at least n lines in the space which intersect both A and B.When A = B, this result reduces to a theorem of De Bruijin and Erdös (1948)
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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