1,721,174 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
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
Pulse-to-pulse stability of GaN HEMT power amplifiers for radar applications in S-band
No full textLes systèmes radar nécessitent d’être de plus en plus performants et doivent émettre des impulsions les plus identiques possibles. Un critère permet de quantifier la bonne régularité des impulsions radar au cours du temps : la stabilité pulse à pulse. L’amplificateur de puissance est un élément essentiel du système radar. Dans ce sens, ce travail présente une analyse du critère de stabilité pulse à pulse dans le cas d’un amplificateur HEMT GaN. Les formules mathématiques permettant d’extraire la valeur de la stabilité pulse à pulse des mesures temporelles d’enveloppe sont présentées. La conception et la réalisation d’un amplificateur de puissance RF connectorisé 50 Ω sont décrites. Divers cas de rafales radar ont été étudiés au travers des mesures temporelles d’enveloppe pour en quantifier l’impact sur les valeurs de stabilité pulse à pulse. Un banc de mesure hétérodyne de la stabilité pulse à pulse a été spécialement développé pendant ces travaux de thèse. Finalement, ces résultats de stabilité pulse à pulse ont été utilisés pour optimiser le modèle électrique non linéaire du transistor HEMT GaN afin de prendre en compte lors des simulations temporelles d’enveloppe les effets de la thermique et des pièges.Radar-oriented applications require stringent performances. Among them, emitting pulse train with uniform envelope characteristics in term of amplitude and phase. The criterion to quantify the self-consistency of radar signals over the pulse train is the pulse to pulse stability. The power amplifier is the most critical element in the RF radar chain because it has a strong impact on the overall pulse to pulse stability performances. In this context, this work is focused on the study of the impact of a HEMT GaN power amplifier on the pulse to pulse stability. Mathematical approach is presented to derive the pulse to pulse stability from time domain envelope measurements. Design and implementation of a 50Ω matched RF power amplifier are presented. Different radar bursts scenario are investigated and their impact on the pulse to pulse stability are quantified through extensive time domain envelope measurements. For that purpose, a dedicated experimental heterodyne time domain envelope test bench has been developed. These pulse to pulse stability measurements are finally used to optimize and fully validate a nonlinear electrical model of a HEMT GaN, allowing to quantify the relative impact of thermal and trapping effects during circuit envelope simulation in radar-oriented applications
Measurements and 2-tone Harmonic Balance Simulations of P2P Performance ofHEMTGaN Transistors
No full textCe travail de thèse a permis de décrire, pour la première fois à notre connaissance, une comparaison des performances Pulse à Pulse (P2P) d'un HEMTAlGaN/GaN obtenue, expérimentalement d'une part grâce à un système de caractérisation entièrement étalonné et d'autre part, grâce à une simulation Harmonic Balance (HB) 2tons d'un modèle fonderie du transistor. Les mesures et les simulations HB permettent l'extraction simultanée et cohérente, d'une part, des enveloppes complexes des tensions et courants hyperfréquences (RF) et, d'autre part, du courant de drain Basse Fréquence (BF) généré par les non-linéarités des composants mesurés ou de leurs modèles électrothermiques simulés. Les enveloppes complexes de tension et de courant aux deux ports des dispositifs sous test (DST) et de la tension et du courant (BF) de drain ont été simultanément mesurées/simulées avec une rafale radar irrégulière périodique composée d'impulsions transitoires ultra courtes et en utilisant les mêmes rafales radar dont, la largeur d’impulsion t et les temps de montée/descente ont été modifiés. L’originalité majeure de ce travail réside dans le fait que les formes d'onde RF générées dans le domaine temporel utilisées par les sources du banc de test ou celles des simulation sont été corrigées pour réduire considérablement les phénomènes de Gibbs.Les facteurs de Lanczos/Fejér ont été implémentés dans des simulateurs. En revanche, à notre connaissance, c'est la première fois qu'ils sont directement utilisés pour générer un signal utile dans un système de caractérisation micro-ondes et dans une simulation HB 2tons.This work describes, for the first time to our knowledge, a comparison of Pulse to Pulse (P2P) stabilities of an AlGaN/GaN HEMT experimentally extracted thanks to an on-wafer fully calibrated characterization system and on the other hand, from a Harmonic Balance (HB) two-tone simulation of a foundry-based model of the transistor. For the first time, Lanczos and Fejér factors are experimentally implemented in the time-domain characterization system in order to reduce the Gibbs phenomen on effects and to perform causal measurements.Thanks to these two tools, the complex envelopes of the microwave (RF) voltages and currents and the Low-Frequency (LF) drain current have been measured/simulated. The complex RF voltage/current envelopes at both ports of the DUT and the LF drain voltage/current have been simultaneously measured/simulated using a periodic irregular radar burst.The P2P stability criterion has been calculated, in this work, using two mathematical expressions (RMS/ET).These two methods are based on the use of the amplitude/phase or the real/imaginary of the measured/simulated (HB 2tone) complex envelopes of the RF output voltage. Ultra-short transient pulses(13ns) have been used. Simulation preliminary results are processing. They will constitute a solid preparation for the future work
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
