1,720,978 research outputs found
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
High Efficiency solar cells based on Czochralski-grown upgraded metallurgical-grade silicon wafers
Full text linkWith the expansion of the PV industry, the cost is coming down significantly. Still, polysilicon is one of the highest capital expenditure components of the PV module production. Solar grade silicon feedstock material purified from a metallurgical route, known as upgraded metallurgical grade (UMG) silicon feedstock, can be a low cost and a smaller carbon footprint alternative for standard electronic grade silicon (EG Si). However, metallurgical refinement techniques are less efficient at removing impurities than the conventional Siemens process, and hence UMG-Si usually contains more impurities than EG Si. These impurities can limit the bulk quality in the as-grown state and enhance degradation during high temperature processes, as a result reducing efficiency. The reduction in efficiency can directly increase the cost of the total PV systems. Thus any significant reduction in efficiency is not tolerable, even if the feedstock cost can be strongly reduced. Firstly, in this thesis, defect engineering of the n-type UMG Cz wafers was performed and demonstrated that the bulk quality of the UMG Cz wafers was primarily limited by the grown in oxygen precipitate nuclei as well as metallic impurities. Further, after a high temperature processing step such as boron diffusion, the bulk quality of the UMG Cz degraded significantly due to ring defects. As a result, the performance of solar cells fabricated on the as grown UMG Cz wafers will be limited by their bulk quality. Fortunately, several preventive and curative treatments, namely tabula rasa, phosphorus diffusion gettering, and hydrogenation in isolation and combination, were identified and demonstrated to improve the bulk quality of these wafers. Further, several experimental investigations were performed on the formation of ring defects in both EG Cz and UMG Cz silicon wafers. A faster onset of ring defects in UMG Cz samples was observed in comparison to EG Cz samples. Furthermore, the combination of FTIR line scans and micro PL and micro Raman maps showed that the ring defects which appear as a continuous band under standard PL image are in fact, a cumulative effect of individual recombination sites. Lastly, the thesis presents solar cell results to elucidate the benefit of applying pre fabrication treatments in these UMG wafers. With the pre-fabrication treatments, the silicon heterojunction solar cells based on the UMG Cz and EG Cz wafers showed a marked improvement in the efficiency from 18.0% to 21.2% and 21.2% to 22.7%, respectively. Comparison of the open circuit voltages of the as grown and pre-treated UMG Cz and EG Cz cells using Quokka simulations reveals that the bulk lifetime remains the primary limiting factor for the UMG Cz wafers. Also, in this thesis, a high efficiency solar cell process is modified by selecting a single boron diffusion step and applying phosphorus doped polycrystalline films as electron selective contacts with excellent impurity gettering properties to minimize the thermal budget. The application of this modified high efficiency solar cell process to n type UMG Cz wafers results in a solar cell with a record conversion efficiency of 22.6%
Frequency of occurrence of different types of orthostatic reactions of blood pressure in healthy volunteers
Full text linkScientific advisers: Zhuravka N.V., Assistant of the Department of
Internal Medicine,
Yabluchanskyi M.I., Doctor of Medicine, PhD, Full
Professor, Head of the Department of Internal
Medicin
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
VERTICAL IRREGULARITY EFFECT ON FUNDAMENTAL TIME PERIOD AND CRITICAL COLUMNS OF BUILDING STRUCTURES
No full textA continuous load path in a structure is always the best way to transmit the load from the upper story to the foundation. However, there is a tradition of using irregular shapes of structures nowadays to enhance the aesthetic, make a terrace, or for getting sunlight. This irregular shape disrupts the continuous load path of the structure and there is the formation of a high-stress zone in the structure which may lead to failure in case of extreme events. During the event of an earthquake, a structure that has an irregularity in its mass, stiffness, and strength suffers more damage as compared to its regular counterpart. So, we need to pay more attention while designing the irregular structure so that it can withstand the force acting on it and ensure the safety of people. So, in this thesis, the seismic response of structures with vertical irregularity is studied. For this purpose, the fundamental time periods of the structures with vertical irregularity are studied and compared with their regular structure. The obtained result is compared with the approximate fundamental period, Ta, given by ASCE/SEI 7-16. Also, the location of critical columns which has the highest load ratio is studied and designed
Frequency of occurrence of different types of orthostatic reactions of blood pressure in healthy volunteers
No full textScientific advisers: Zhuravka N.V., Assistant of the Department of
Internal Medicine,
Yabluchanskyi M.I., Doctor of Medicine, PhD, Full
Professor, Head of the Department of Internal
Medicin
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
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