1,720,957 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
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
Refined computational modeling of SOFCs degradation due to trace impurities in coal syngas
Get PDFThe Solid Oxide Fuel Cell (SOFC) is a good alternative for clean and efficient power generation. These cells can be operated directly on a wide variety of fuels including biogas, hydrocarbon fuels and synthesized coal gas (syngas), which is a promising avenue for utilization of coal with much less environmental impact. One of the challenges in this technology is poisoning of SOFC anodes by trace impurities contained in coal syngas. One such impurity, phosphine is known to cause catastrophic failure of SOFC anode even at \u3c10ppm concentrations. Fuel impurity degradation patterns can vary by different operating conditions such as humidity, applied current, temperature and anode thickness.;In the present study, more detailed models are developed to predict the typical degradation behaviors observed in SOFC anode due to phosphine by extension of an in-house one-dimensional computational code. This model is first used to predict the effect of steam concentration on phosphine induced degradation in anode supported SOFCs. The model is refined based on the experimental observation, which indicate that the phosphine degradation is less severe in the absence of steam. Simulations results showed good agreement with experimental data. Then, a sensitivity analysis, using dual numbers automatic differentiation (DNAD) is performed to investigate the influence of empirical model parameters on model outputs, electrical potential, ohmic and polarization losses. Further, the refined one-dimensional model is extended to a three-dimensional model to study the phosphine induced performance degradation in relatively large planar cells operating on hydrogen fuel. The empirical model parameters are calibrated using button cell experiments and sensitivity analysis as a guide. These parameters are then used in planar cell simulations. The results from the three dimensional model show that the contaminant coverage of nickel and fuel distribution inside the anode is highly non-uniform. These non-uniform distributions are caused by the geometrical alignment of gas channels and current collectors, as well as the variation of gas concentration along the flow direction. The non-uniform deactivation of anode gave rise to the altering of current distribution inside the planar cell such that the cell can still produce current even when some regions of the anode are partially inactive. In addition, to assess the overall cell performance at any given degradation stage, additional simulations are performed to evaluate the electrochemical behavior (polarization and impedance) of the cell. The simulation results are assessed in comparison to experimental observation whenever possible. Finally, a physics based transport model for nickel migration is formulated based on experimentally observed elemental redistribution in a SOFC anode and it is integrated into refined one-dimensional phosphine degradation code. Simulations show that the proposed mechanism of Ni diffusion driven by secondary phase formation, the electrical force, and humidity can explain the experimentally observed accumulation of Ni and secondary phases on the SOFC anode surface.;Keywords: Keywords: Solid Oxide Fuel Cells, Contaminant Degradation, Automatic differentiation, Sensitivity Analysis, Impedance, Polarization, Nickel migration, Electro-migration.
Mathematical Modeling Of Dislocation-fiber Interactions In Composite Materials
No full textTez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009Bu çalıĢmanın amacı, kompozit malzemelerde N adet ayrık kenar dislokasyonuna uygulanan kayma gerilmesi sonucu dislokasyonların fiber yüzeyine olan uzaklığını bulmaktır. N tane ayrık kenar dislokasyonu için N tane lineer olmayan denklem oluşturuldu. Oluşturulan lineer olmayan denklem sistemleri, 30 tane ayrık kenar dislokasyonu için çözüldü. Fiber kompozitlerde ayrık dislokasyonların yerleri; uygulanan gerilme, fiber çapı, anafazın kayma gerilmesi ve fiber fazların kayma modülleri gibi parametrelere bağlıdır. Bu çalışmada iki önemli durum incelenecektir. Bunlardan birincisi kayma düzlemindeki kayma gerilmesi, uygulanan boyutsuz gerilmeye bağlı olarak incelenecektir. İkinci durumda ise kayma düzlemindeki kayma gerilmesi, elde edilen boyutsuz dislokasyon yığılma konumlarına bağlı olarak incelenecektir. Aynı zamanda, optimizasyon üç farklı kompozit, Al/Al2O3, Cu/WC ve Al/SiC, için uygulandı.The aim of this study is to find positions of multiple edge dislocations in a pile-up against a circular/cylindrical interface. An optimization procedure was applied for the solution of nonlinear equations. For multiple edge dislocations, there are multiple nonlinear equations. For 30 dislocation, 30 nonlinear equations had been optimized. The position of discrete dislocations in a fiber composite depends on some different parameters, such as applied stres, fiber radius, shear modulus of matrix and fiber phases…etc. Applied stres can be very important for dislocations positions. In this study, two very important cases will be investigated. Firstly, the effect of varying τapp/μ1 (dimensionless applied stres) for tip shear stress and secondly the effect of changing microstructure, varying Λ (dimensionless pile-up length) for tip shear stress will be investigated. And also the optimization will be applied for three different composites, Al/Al2O3, Cu/WC and Al/SiC.Yüksek LisansM.Sc
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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