1,721,040 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
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
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
Contribution à l’estimation des mouvements sismiques à l’aide de la simulation numérique
No full textAuthor-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Seismic wave attenuation in scattering media : insights from numerical simulations and estimates from seismic ambient noise
No full textParmi les processus physiques qui contrôlent les caractéristiques des ondes sismiques, l'atténuation est probablement le facteur le moins compris et le plus mal estimé. Globalement, l'atténuation sismique est contrôlée par deux mécanismes: la diffusion, qui est la redistribution d'énergie due aux hétérogénéités à petite échelle; et l'absorption, qui est la dissipation d'énergie due à la présence de fluides ou à la friction interne. Estimer ces propriétés est crucial pour la prédiction appropriée des mouvements sismiques du sol lors d'un tremblement de terre, ainsi que pour caractériser les structures à petite échelle de la Terre. Malgré cette importance, l'estimation des propriétés d'atténuation et de leurs effets sur la prédiction des mouvements sismiques demeure, dans une certaine mesure, sujette à des interprétations incertaines. Nous présentons une étude complète sur l'atténuation des ondes sismiques dans des milieux hautement hétérogènes, dans laquelle nous utilisons des simulations numériques, des modèles théoriques et des données réelles provenant du bruit sismique ambiant.La première partie de notre travail consiste en l'analyse de la propagation des ondes SH dans des milieux aléatoires 2D. À l'aide d'un ensemble de comparaisons entre résultats de simulations numériques du champ d'ondes complet et ceux de modèles théoriques tels que le champ moyen et le transport radiatif, nous proposons une procédure de vérification qui vise à éclairer la compréhension des effets de diffusion dans les simulations des mouvements du sol. De plus, nous étudions la transition entre différents régimes de propagation, passant des comportements balistiques aux comportements diffusifs à partir de l'exploitation des enveloppes d'énergie des sismogrammes synthétiques. Nous nous concentrons sur la dépendance avec la distance du pic d'énergie des enveloppes, qui est un paramètre clé pour l'évaluation du risque sismique. Ainsi, en analysant la décroissance avec la distance et les fluctuations statistiques du pic de l'énergie, nous mettons en évidence une distinction claire entre les rôles des libre parcours moyens de diffusion et de transport.Le but final de ce travail est de proposer une technique permettant de caractériser séparément les propriétés d'absorption et de diffusion des ondes sismiques à l'échelle locale. À cette fin, nous utilisons des données continues de bruit sismique ambiant sur une période de quatre ans au volcan Piton de la Fournaise, pour des fréquences comprises entre 0,5 et 4 Hz. Notre technique consiste à profiter des avantages que différentes gammes de distances de propagation peuvent offrir. De cette manière, les mesures d'atténuation sont effectuées en deux étapes : (i) nous caractérisons d'abord l'absorption en utilisant de courtes distances de propagation, car les enveloppes d'énergie correspondantes présentent des durées de coda suffisamment longues pour mesurer une décroissance robuste dans le temps; et après (ii) l'atténuation due à la diffusion est mesurée à partir de distances de propagation longues, car les effets des inhomogénéités à petite échelle deviennent plus prononcés et facilement distinguables lorsque la distance augmente.Among the physical processes that control the characteristics of seismic waves, attenuation is probably the least understood and the most poorly estimated factor. Globally, seismic attenuation is controlled by two mechanisms: scattering, which is the energy redistribution due to small-scale heterogeneities; and absorption, which is the dissipation of energy due to the presence of fluids or internal friction. Estimating these properties is crucial for the appropriate prediction of the earthquake ground motions, as well as to characterize the small-scale structures of the earth. Despite its relevance has been widely recognized, the estimation of attenuation properties and their effects on the predicted ground motion remains, in some extent, unclear for interpretation. Here we present a comprehensive study on the attenuation of seismic waves in highly heterogeneous media, in which we make use of numerical simulations, theoretical models and real data from seismic ambient noise.The first part of our work consists in the analysis of the SH wave propagation in 2D random media.By a set of comparisons between results from numerical simulations of the full-wavefield with those from theoretical models such as the mean field and the radiative transfer theories, we propose a verification procedure that aims to shed some light on the understanding of the scattering effects in the ground motion simulations. Additionally, we study the transition between different propagation regimes, from ballistic to diffusive behaviors by exploiting the energy envelopes of our synthetic full-waveforms. We focus on the distance dependence of the peak energy envelope, which is a key parameter for the seismic hazard assessment. Thus, by analyzing the decay with distance and the statistical fluctuations of the peak energy, we show a clear distinction on the roles of the scattering and the transport mean free paths.The final goal of this work is to propose a technique to characterize separately absorption and scattering properties at a local scale. To this end, we use continuous data of seismic ambient noise over four years at the Piton de la Fournaise volcano for frequencies between 0.5 and 4 Hz. Our technique consists in profiting the advantages that different ranges of propagation distances can exhibit. In this way, attenuation measurements are performed in two stages: (i) we first constrain absorption by using short propagation distances as the corresponding energy envelopes show coda durations long enough to measure a robust decay with time; and secondly (ii) scattering attenuation is measured from long propagation distances since the effects of small-scale inhomogeneities become more pronounced and easly distinguished when distance increases
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