1,721,001 research outputs found
Discretization error estimation for EU‐DEMO plasma‐edge simulations using SOLPS‐ITER with fluid neutrals
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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
Impact of inter-pulse wall outgassing on ITER plasma start-up
Get PDFLAUREA MAGISTRALEI tokamak sono una promettente tecnologia che in futuro potrebbe fornire elettricità pulita sfruttando la fusione nucleare come fonte di energia. Il reattore consiste in una camera toroidale dove dei campi magnetici confinano un plasma ad alta temperatura, in cui avviene la reazione. I tokamak sono reattori ad impulso, la reazione non può avvenire continuamente. Un potenziale fattore limitante per il tempo di attesa tra due impulsi consecutivi è il desorbimento termico dalle pareti di atomi precedentemente impiantati durante il plasma. Il rilascio di gas crea una sovrappressione nel reattore che compromette la condizione di vuoto necessaria per il successivo avvio del plasma. La pressione parziale dell'idrogeno deve essere infatti inferiore a una certa soglia, di 0.5 mPa per ITER. L'obiettivo di questa tesi è studiare le cause di diverse condizioni di desorbimento in JET, con il fine di ottenere una stima del tempo di attesa in ITER. Il primo approccio utilizzato è sperimentale. Vengono trovate correlazioni tra la pressione dopo un impulso in JET e diversi parametri del plasma. La pressione risulta positivamente correlata con l'energia immessa nel plasma e la pressione di base nel reattore, dimostrando che il desorbimento dipende anche dagli impulsi precedenti. L'evoluzione temporale della pressione viene studiata e confrontata con la letteratura, trovando una nuova funzione che la descrive più accuratamente. Un'analisi dettagliata di alcuni esperimenti ha dimostrato che il desorbimento aumenta durante impulsi consecutivi, a causa dell'aumento di temperatura e della progressiva saturazione delle pareti. Si osserva anche l'impatto delle disruptions e della configurazione del plasma. Il codice MHIMS viene poi utilizzato per riprodurre le osservazioni sperimentali con la modellazione numerica. Le pareti di JET vengono modellate e viene simulata una serie di impulsi intervallati da fasi di desorbimento. La pressione ottenuta dalla simulazione concorda con quella reale, le osservazioni sperimentali vengono riprodotte correttamente. Il modello fisico viene estrapolato a ITER, adattando superfici e condizioni operative. La curva di pressione ottenuta dalla simulazione prevede che in 10-15 minuti, aumentando con impulsi consecutivi, la pressione parziale dell'idrogeno sarà sufficientemente bassa, in accordo con la letteratura. Questo dimostra che il desorbimento non limiterà fortemente il tempo di attesa. Altri vincoli, come la concentrazione delle impurità, potrebbero essere il fattore limitante.Tokamaks are a promising technology that could provide baseload clean electricity in the future exploiting nuclear fusion as energy source. The device consists of a toroidal chamber where magnetic fields are used to confine a high temperature plasma where the reaction happens. Tokamaks are pulsed machines, they cannot operate continously. A potential limiting factor for the inter-pulse waiting time is the process of outgassing, the thermal desorption of particles from the wall which were previously implanted during plasma operation. The released gas creates an overpressure in the reactor that hampers the vacuum conditions needed for plasma start-up. The hydrogen pressure needs to be below a certain threshold, 0.5 mPa for ITER. The objective of this thesis is studying the reasons for different outgassing conditions at JET, in order to have an estimate of the dwell-time at ITER. This is first addressed with an experimental method. Correlations are found between the pressure values at different times after a JET discharge with pulse parameters. A positive correlation is found with energy and background pressure, the latter meaning that the outgassing depends on previous pulses through a memory effect. The time evolution of the pressure is studied and compared with literature, finding a more accurate way to describe it mathematically. Finally, a detailed analysis of specific experiments confirmed that a memory effect exists and depends on temperature increase and progressive loading of the wall during consecutive shots. The impact of disruptions and plasma configuration is also clearly observed. A physical modelling approach is then taken to reproduce the experimental observations, using the simulation code MHIMS. The PFCs of JET are modeled and a series of plasma shots with inter-pulse outgassing are simulated. The pressure obtained from the simulation agrees with experimental data and the memory effect is correctly reproduced. Finally, the physical model is extrapolated to ITER, adapting the surfaces involved and the input operational data. The simulation of consecutive shots is run for ITER and an estimate for the pressure curve during dwell-time is obtained. The results agree with previous literature and find that in 10 to 15 min, increasing with consecutive shots, the hydrogen pressure will be low enough. This proves that outgassing will not impose a strong limitation to dwell-time. Other constraints on plasma start-up such as impurity concentration may be the limiting factor
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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