1,721,284 research outputs found
Exponential asymptotics for integrals with degenerate and non-isolated critical points
Get PDFIn this thesis we consider the exponentially improved asymptotic solutions to unbounded multidimensional steepest descent type integrals in the case where the phase function has sets of non-isolated critical points. These sets are connected components of the critical set of the phase function and we consider the case where these sets have both general order of degeneracy and general dimension. We consider first the case of isolated critical points of general order of degeneracy as a lead-in to the general problem.
In the isolated case, we justify the reduction of the study of the asymptotic behaviour of the general integral to the study of the asymptotic contribution to each individual critical point by appealing to the Morse lemma and results from the literature regarding the homology group of allowable integration surfaces. In the non-isolated case no such results exist, but we give a first step by appealing to the Morse-Bott lemma to suitably parameterise the integration surface. The analogous homological result does not yet exist and such a derivation is beyond the scope of this thesis, but we proceed to study individual contributions regardless, inspired by how readily the Morse-Bott lemma affords an analogous parameterisation of the integration surface in the non-isolated case.
Once this justification is established we focus on individual critical connected components of the phase function. A full hyperasymptotic expansion representing the repeatedly exponentially improved asymptotic contribution to the integral for critical points of this type is derived for the first time, with examples provided to demonstrate this new theory. The case of a general bounded integration region is briefly considered, but we demonstrate that work still needs to be done to extend the theory to this case
Sometimes in summer [music] : song /
No full textH. 7088 (Publisher number). "No. 1 in D".; Pl. no.: H. 7088.; Also available online http://nla.gov.au/nla.mus-an11312482
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
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