1,721,086 research outputs found
Measurement of the sound absorption coefficient of materials with a new sound intensity technique
Full text linkThe paper presents a completely new measurement technique of the sound absorption properties of materials, based on the measurements of active intensity and sound energy density.
It allows one to measure the absorption coefficient with a wide band excitation, to use frequency bands of any width and to make measurements both inside a tube or in situ.
The intensity technique is compared to Transfer Function Method (as defined in the ASTM E-1050 standard), by means of a complete theoretical study and of a large experimental validation.
The results suggest that the new method is at least as accurate and reliable as the ASTM E-1050 standard. It also has many advantages: it is faster, easier, it directly produces results in 1/3 or 1 octave bands, it can be implemented with portable, low cost instrumentation
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
A Torelli theorem for the moduli space of parabolic Higgs bundles
No full textAbstract
In this article we extend the proof given by Biswas and Gómez [Quart. J. Math. 54: 159–169, 2003] of a Torelli theorem for the moduli space of Higgs bundles with fixed determinant, to the parabolic situation.</jats:p
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
Theta-duality on Prym varieties and a Torelli Theorem
No full textLet be an unramified double covering of irreducible smooth curves and let be the attached Prym variety. We prove the scheme-theoretic theta-dual equalities in the Prym variety and , where is the Brill-Noether locus of associated to considered by Welters. As an application we prove a Torelli theorem analogous to the fact that the symmetric product of a curve of genus determines the curve
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