1,720,976 research outputs found
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
Convergence Rate Analysis of Markov Chains
Full text linkWe consider a number of Markov chains and derive bounds for the rate at which convergence to equilibrium occurs. For our main problem, we establish results for the rate of convergence in total variation of a Gibbs sampler to its equilibrium distribution. This sampler is motivated by a hierarchical Bayesian inference construction for a gamma random variable. The Bayesian hierarchical method involves statistical models that incorporate prior beliefs about the likelihood of observed data to arrive at posterior interpretations, and appears in applications for information technology, statistical genetics, market research and others. Our results apply to a wide range of parameter values in the case that the hierarchical depth is 3 or 4, and are more restrictive for depth greater than 4. Our method involves showing a relationship between the total variation of two ordered copies of our chain and the maximum of the ratios of their respective co-ordinates. We construct auxiliary stochastic processes to show that this ratio does converge to 1 at a geometric rate. In addition, we also consider a stochastic image restoration model proposed by A. Gibbs, and give an upper bound on the time it takes for a Markov chain defined by this model to be arbitrarily close in total variation to equilibrium. We use Gibbs' result for convergence in the Wasserstein metric to arrive at our result. Our bound for the time to equilibrium is of similar order to that of Gibbs
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
Stochastic and Renewal Methods Applied to Epidemic Models
Full text linkThe thesis is made up of three chapters, which analyse the disease spreads within the population
in three different settings.
The first chapter analyses the effects of the adaptive vaccination strategy on the infectious
disease dynamics in a closed population and a demographically open population. The
analytical methods are used to show that the cumulative force of infection for the closed
population and the endemic force of infection in the demographically open population
can be significantly reduced by combining two factors: the vaccine effectiveness and the
vaccination rate. The impact of these factors on the force of infection can transform an
endemic steady state into a disease free state.
The second chapter analyses the SIS Epidemic dynamics using the Birth-Death Markov
processes. The Susceptible-Infected-Susceptible (SIS) model is defined with the population
of constant size (M); the susceptible population (S) and the infected population
(I) have the same rate of birth and death (mu); the disease spreads with the transmission
rate (beta). Using a stochastic method, it is shown that the magnitude of the disease spread
depends on the Reproductive Number (R = beta/mu). In the long run, the stochastic equilibrium
and the deterministic equilibrium yield the same infected size equilibrium (1-(1/R)) in
proportion. Finally, the asymptotic distribution of the infected size is shown to follow a
normal distribution with mean (1-(1/R))M and variance (M/R).
The third chapter studies the impact of the Gamma distribution of the individual lifetime
on the SIS Epidemic Dynamic. The approaches are both numerical and analytical
methods. The composite Newton-Cotes quadrature formulas are implemented in order
to provide the best accurate estimation of the infected size equilibrium. The numerical
solution of the infected size was computed and the results show that the infected size is
an increasing function of the shape parameter (k) with a phase of acceleration and a phase
of deceleration before reaching a stable value (1-(1/(2R))). The numerical solution was also
compared with the analytical solution provided by the Extreme Value Theory. The results
consolidate the numerical solutions of the infected size. However, the analytical approximation is not valid for shape parameters (k) less than 1
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