1,720,986 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
Studies in Multivariate Pareto Records
Get PDFThe natural and important notion of multivariate Pareto record is defined based on the dominance relation in and generalizes the classical notion of one-dimensional record in probability theory. Given a sequence of independent and identically distributed random vectors taking values in with continuous distribution function, we first investigate how the probability that the th observation sets a record varies with their common distribution. Then, for observations with independent coordinates, we study the asymptotic behavior (as ) of the Pareto frontier, defined simply in terms of the remaining records (i.e., maxima, or undominated points) at a given epoch , by deriving distributional and almost sure extreme results. These results are then extended to observations that follow a certain class of marginalized Dirichlet distributions, which exhibit negative dependence among the coordinates. For such marginalized Dirichlet observations, we also prove Berry--Esseen bounds for both the total number of records set and the number of remaining records using Stein's method. Finally, for the two models, we introduce a probabilistic approach to identify, with proofs, the asymptotic conditional distribution of the number of Pareto records broken by the th observation conditionally given that the observation sets a record
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
Studies in Multivariate Pareto Records
Get PDFThe natural and important notion of multivariate Pareto record is defined based on the dominance relation in and generalizes the classical notion of one-dimensional record in probability theory. Given a sequence of independent and identically distributed random vectors taking values in with continuous distribution function, we first investigate how the probability that the th observation sets a record varies with their common distribution. Then, for observations with independent coordinates, we study the asymptotic behavior (as ) of the Pareto frontier, defined simply in terms of the remaining records (i.e., maxima, or undominated points) at a given epoch , by deriving distributional and almost sure extreme results. These results are then extended to observations that follow a certain class of marginalized Dirichlet distributions, which exhibit negative dependence among the coordinates. For such marginalized Dirichlet observations, we also prove Berry--Esseen bounds for both the total number of records set and the number of remaining records using Stein's method. Finally, for the two models, we introduce a probabilistic approach to identify, with proofs, the asymptotic conditional distribution of the number of Pareto records broken by the th observation conditionally given that the observation sets a record
The sum of powers of subtree sizes for conditioned Galton-Watson trees
No full textWe study the additive functional X-n(alpha) on conditioned Galton-Watson trees given, for arbitrary complex alpha, by summing the alpha th power of all subtree sizes. Allowing complex alpha is advantageous, even for the study of real alpha, since it allows us to use powerful results from the theory of analytic functions in the proofs. For Re alpha < 0, we prove that Xn(alpha), suitably normalized, has a complex normal limiting distribution; moreover, as processes in alpha, the weak convergence holds in the space of analytic functions in the left half-plane. We establish, and prove similar process-convergence extensions of, limiting distribution results for alpha in various regions of the complex plane. We focus mainly on the case where Re alpha > 0, for which X-n(alpha), suitably normalized, has a limiting distribution that is not normal but does not depend on the offspring distribution xi of the conditioned Galton-Watson tree, assuming only that E xi = 1 and 0 < Var xi < oo. Under a weak extra moment assumption on xi, we prove that the convergence extends to moments, ordinary and absolute and mixed, of all orders. At least when Re alpha > 21, the limit random variable Y(alpha) can be expressed as a function of a normalized Brownian excursion.Correction in: Electron. J. Probab. 28:1-2 (2023).DOI: 10.1214/23-EJP915</p
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
A local limit theorem for QuickSort key comparisons via multi-round smoothing
No full textNon UBCUnreviewedAuthor affiliation: The Johns Hopkins UniversityFacult
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