1,720,955 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
수소저장합금 및 과산화수소를 활용한 산소희박환경에서의 연료전지 시스템용 연료 공급 전략에 관한 연구
No full text학위논문(박사) - 한국과학기술원 : 기계공학과, 2025.2,[vii, 128 p. :]Fuel cell systems utilizing hydrogen energy are gaining attention globally as next-generation power systems due to their environmental friendliness and high efficiency. Underwater vehicles operating in low-oxygen environments require high energy storage density in their power systems to ensure sufficient submersion time. Consequently, efforts have been made to replace Li-based batteries, which have low energy storage density, with fuel cell systems. Various countries have developed unmanned underwater vehicles (UUVs) equipped with fuel cell systems. However, small UUVs with power requirements of several hundred watts face disadvantages in energy storage density due to the simultaneous need for hydrogen and oxygen sources in low-oxygen environments. Liquid fuels with high energy density are challenging to apply to small systems and are unsuitable for long-term storage due to boil-off. Compressed tanks, on the other hand, pose safety issues due to high pressure and have low fuel storage density.
This study introduces the use of metal hydrides and hydrogen peroxide for the fuel cell system in small underwater vehicles. Metal hydrides offer high hydrogen storage density, low operating temperature, and pressure, making them suitable for room-temperature fuel cell systems. Metal hydrides undergo exothermic reactions during hydrogen absorption and endothermic reactions during desorption. Thus, when supplying hydrogen to the fuel cell, the hydrogen desorption reaction of metal hydrides requires heat. Hydrogen peroxide is an appropriate oxygen storage material that can provide heat to metal hydrides. It decomposes into water, oxygen, and heat through catalytic reactions. The heat generated from the decomposition of hydrogen peroxide is higher than the desorption heat required by the metal hydrides, ensuring stable hydrogen supply.
To apply metal hydrides, which have been primarily used for stationary and power generation purposes, to fuel cell systems in underwater vehicles, a suitable metal hydride with high hydrogen storage density and appropriate operating conditions was selected. The chosen AB2-type metal hydride has high volumetric hydrogen storage density, but the inherent low thermal conductivity of metal hydrides needed to be addressed. Copper, with high thermal conductivity, was placed inside the cylinder, and optimal internal thermal design was achieved using thermal resistance comparison methods. The introduction of internal thermal design improved hydrogen storage capacity and desorption rate during charging and discharging.
For the decomposition of hydrogen peroxide, Pt/CGO, which demonstrated stable decomposition rates, was used. The Pt/CGO catalyst maintained stable decomposition of hydrogen peroxide for up to 300 hours. A thermal management module was designed to effectively transfer the latent heat of the high-temperature wet oxygen to the metal hydride. The thermal management module employed a direct heat exchange method, allowing high-temperature wet oxygen to flow outside the metal hydride cylinder. The appropriate flow channel thickness and module outer diameter for effective heat exchange were determined through fluid thermal analysis modules, and experiments were conducted using a scaled-down model. With external thermal management, hydrogen desorption time was reduced by 62%, and the required hydrogen flowrate for the fuel cell was maintained during most of the hydrogen desorption process.
Finally, integrated operation of a fuel cell system using hydrogen storage alloy and hydrogen peroxide was performed. Hydrogen and oxygen were supplied to a water-cooled PEMFC stack in a dry state. The fuel cell achieved a fuel utilization rate of over 90% through dead-end operation. This fuel cell system can supply an average power of 293 W for 96 hours with a single charge, and the theoretical system energy density is 380 Wh/L. Through this, the applicability as a fuel cell power system in a low oxygen environment was confirmed.한국과학기술원 :기계공학과
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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