1,721,048 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
Theoretical analysis of polarization characteristics of InGaN/GaN LEDs with photonic crystals
No full textWe investigated theoretically the polarization characteristics of GaN-based green (525 nm) light-emitting diodes (LEDs) with photonic crystals (PCs) using a three-dimensional finite difference time domain method. The light extraction efficiency depends strongly on the photonic bandgap (PBG) position relative to a frequency (a/λ) and the depth of air hole for transverse electric (TE) and transverse magnetic (TM) polarizations. The maximum extraction efficiency was achieved when the frequency of a/λ was matched within PBG region, leading to about 29% (22%) higher than the conventional LED without photonic crystals for TE (TM) polarization. It is found that the polarization of light can be controlled by the a/λ in PC structure
Fabrication of antireflection nanostructures on GaAs by holographic lithography for device applications
No full textWe demonstrate the fabrication of antireflection nanostructures on GaAs using holographic lithography. Measured results of the fabricated nanostructures are in good agreement with the calculated values using a RCWA model, effectively suppressing the surface reflection over visible and near-infrared ranges
Subwavelength antireflection structures and their device applications
No full textWe report the subwavelength antireflection structures in various semiconductor materials such as Si, ZnO, and GaP/light emitting diode (LED) structure for LED and solar cell applications in the visible and near-infrared wavelength region, together with the rigorous coupled wave analysis simulation. Subwavelength structures are fabricated by holographic lithography and dry etching, effectively suppressing the surface reflection. To enhance the absorption efficiency over a wide-angle broadband range of incident light, the thin-film crystalline Si solar cells with subwavelength structure, which reduce the surface reflection, are studied. The improvement of light intensity is achieved for the fabricated LEDs with a subwavelength structure compared to the conventional LEDs due to a strongly reduced internal reflection at the semiconductor/air interface
Effect of AZO deposition on antireflective property of Si subwavelength grating structures
No full textWe investigate the effect of the aluminum-doped zinc oxide (AZO) deposition on the fabricated Si SWG structure on its antireflection characteristics for solar cell applications. The Si SWGs with the two-dimensional periodic nanostructure are fabricated by using holographic lithography and subsequent ICP etching process in SiCl 4 plasma. For the antireflection analysis of AZO thin-film on the Si SWG structure, the optical reflectivity is measured experimentally. The maxima reflectance and its oscillation of the structure are significantly decreased on average than those of AZO thin-film on Si substrate over a wide wavelength range of 300-1100 nm, indicating average reflectance less than 4.5% with the maxima of & < 10%
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
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