1,720,961 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
A scanless method for terahertz time-domain imaging
No full textTerahertz (THz) time-domain imaging can uncover the spectral fingerprints of materials, detect changes in both refractive index and absorption, and reveal the inner structure of complex objects through time-of-flight measurements. Despite its potential, the lengthy acquisition typically required to spatially raster-scan the object and record the terahertz temporal waveforms for each spatial point limits practical applications. Our scanless imaging method sets the path for an unprecedented reduction of both system complexity and acquisition time, by addressing this crucial bottleneck. By judiciously exploiting natural wave diffraction, time-to-space encoding is applied to THz point detection and enables a nearly instantaneous capture of the terahertz waveforms. Multidimensional images are then reconstructed through a computational method. This approach opens the route for next-generation fast and compact THz imagers that are well-suited for high-repetition-rate laser sources
Terahertz Scanless Hypertemporal Imaging
Get PDFSince its first demonstration in 1995, terahertz time-domain imaging has attracted an increasingly growing interest for its ability to reveal spectral fingerprints of materials and probe changes in refractive index and absorption, as well as detect the inner structure of complex objects via time-of-flight measurements. Practically, however, its widespread use has been hampered by the very long acquisition time typically required to spatially raster-scan the object, and for each spatial point, record the field in time via a delay line. Here, this fundamental bottleneck is addressed by implementing a scanless single-pixel imaging scheme, which sets the path for an unprecedented reduction of both system complexity and acquisition time. By properly exploiting natural wave diffraction, time-to-space encoding applied to terahertz point detection allows for an almost instantaneous capture of the terahertz waveforms, while multidimensional images are reconstructed via a computational approach. The scheme is a promising solution for the development of next-generation fast and compact terahertz imagers perfectly suitable for high-repetition-rate laser sources
Scanless terahertz time-domain imaging
No full textThrough diffraction, we combine a single-pixel imaging approach and a single-shot detection technique to achieve scanless time-domain imaging at terahertz frequencies. We also apply compressive sensing to further reduce the acquisition time
Scanless terahertz imaging in the time domain
No full textWe realize scanless time-domain imaging at terahertz frequencies, by combining a single-pixel imaging scheme with a 'single-shot' detection method. We also apply compressed sensing to further speed up the acquisition process
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
- …
