1,721,021 research outputs found
An experimental study of the flow of organic pollutants through compacted clays
No full textThe paper deals with the preparation of an experimental site designed to study the flow of either water or fluid contaminants through a compacted clay liner as well the adsorption capacity of the porous medium and the modifications of its geotechnical propertie
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
Pattern distortion for corrugated horns open-ended on a finite ground plane
No full textA method is proposed for predicting the radiation pattern of rectangular apertures on a finite rectangular ground plane. This method includes an accurate description of single, double and vertex diffraction mechanisms. The first step of the analysis is the full-wave estimation of the aperture field. To this end, the external and the internal regions are separated by replacing each aperture with a metallic plug with equivalent magnetic currents on its external and internal sides; these currents are of equal amplitude and of opposite sign to ensure the continuity of the electric tangential field through the aperture. Then, an integral equation is formulated, that represents the continuity of the tangential H-field through the apertures. To solve the internal-external coupling, the external flange is initially treated as an infinite ground plane. After the determination of the magnetic currents, these currents are considered as radiating on the finite ground plane. For the sake of simplicity, but without loss of generality, a single horn is considered. The internal region of the corrugated horn is analyzed by using a generalized admittance matrix method. © 1999 IEEE
Effetti di tensioattivi anionici e cationici sulla permeabilità: risultati di prove su un limo con sabbia argilloso
No full textGli esperimenti effettuati su un limo e sabbia argilloso hanno evidenziato come l'aggiunta di tensioattivi sia cationici che anionici, in forte concentrazione, determini un incremento di permeabilità intrinseca, di intensità funzione della scala di misur
Line-Integral representation of the field radiated by a rectangular waveguide modal current distribution
No full textAn exact expression in terms of Line integration is presented for the near field of a rectangular waveguide modal current distribution, radiating either in free-space or on a perfectly conducting infinite ground plane. This formulation may be used in the famework of a method of moments (MoM) for reducing the computational time
Studio del flusso di inquinanti in fase non acquosa e tensioattivi attraverso terre argillose.
No full textSono illustrate le caratteristiche tecniche di un allestimento sperimentale per lo studio del flusso di fluidi inquinanti attraverso terre argillose costipat
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