1,720,962 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
Defects and charge-carrier lifetime in early-stage photovoltaic materials : relating experiment to theory
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged student-submitted from PDF version of thesis.Includes bibliographical references (pages 171-187).To minimize risks associated with climate change, we must rapidly reduce greenhouse gas emissions worldwide by shifting reliance away from fossil fuels. Solar photovoltaic (PV) modules are well suited for reducing emissions; however, manufacturing and capital costs must continue to decline for rapid, worldwide PV adoption. Low-cost and Earth-abundant "thin film" materials offer potential in spurring PV growth, but their development is often hampered by the presence of defects, which degrade solar cell efficiency due to short charge-carrier lifetimes. In this thesis, such defects and their impact on lifetime in early-stage PV materials are investigated, focusing on experimental methods to assess lifetime connected to theoretical concepts about both defects and lifetime measurements themselves. First, time-resolved photoluminescence is performed, and both analytical and numerical modeling are used to determine lifetimes exceeding 1 nanosecond in six materials predicted to be "defect tolerant." Two-photon spectroscopy is then employed to decrease the effect of surface recombination, enabling more representative estimates of "bulk" lifetime. Second, the role of impurities is explored by intentionally contaminating lead halide perovskites with iron. Synchrotron-based X-ray techniques are also utilized to investigate the distribution and charge state of incorporated iron, and perovskite solar cells are found to tolerate approximately 100 times more iron in the feedstock than comparable p-type silicon solar cells. In addition, improved methods for extracting lifetime from solar cell devices are explored. Quantum efficiency measurements are performed and modeled on tin monosulfide solar cells to verify that very short lifetimes (30-100 picoseconds) limit device performance. Furthermore, temperature- and illumination-dependent current-voltage measurements are performed and modeled in iron-contaminated silicon solar cells- and analyzed with the help of a Bayesian inference algorithm-to estimate the defect parameters that directly relate to lifetime. Collectively, these studies serve to provide a more robust framework for assessing and mitigating the presence of defects in early-stage PV materials, streamlining efforts to better optimize their photovoltaic performance.by Jeremy Roger Poindexter.Ph. D
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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