1,720,964 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
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
Development of a Plasma Diagnostic System
No full textWith evermore stringent requirements towards pointing accuracy and platform stability, in both commercial and scientific missions, AirbusDS has initiated the development of micronewton class ion engines for applications in attitude control systems. Here the Friedrichshafen branch of AirbusDS pursues the development of a downscaled version of the High EfficiencyMultistage Plasma Thruster (HEMP-T), an electric thruster type currently flown on OHB’s smallGEO bus. In contrast to cold gas systems, which can deliver comparable thrust levels and are currently used as means of attitude control on such highly complex missions as LISA pathfinder, these micronewton HEMP-Ts exhibit a higher performance in terms of specific impulse as well as thrust controllability. With this they enable extended mission lifetime or propellant mass reductions while also increasing attitude control precision. Within the scope of this activity a test facility was developed, consisting of a vacuumchamber containing a thrust balance aswell as the supporting equipment such as vacuum control and data acquisition hardware. In addition to direct thrust measurements performed on each of the design iterations of the thruster it is necessary to investigate the thruster plume geometry and ion energy distribution. While direct thrust measurements, via the highly precise thrust balance already included in the existing test facility, allow for the determination of the thruster performance they do not give an insight into the specific loss mechanisms which cause the observed thrust level or specific impulse to deviate from the ideally attainable values. Here the plume shape can give an indication of the divergence losses encountered by the thruster while the energy of the expelled propellant ions can indicate deficiencies in the thruster design concerning the complex internal magnetic topology necessary for the proper operation of this type of thruster. Building on the experience gathered using an existing, rudimentary, plasma diagnostic system, as well as an extensive literature survey, this document describes the design, development and testing of a plasma diagnostic system based on a novel sensor concept which enables both plume shape determination as well as ion energy distribution measurement in a compact package. This effort includes the redesign of the sensor positioning hardware as well as the associated data acquisition system. Initially an overview of the technologies relevant to this work is given. This includes the description of the basic working principle of the thruster under investigation here, the plasma diagnostic probes which have been deemed viable candidates as an outcome of the preceding literature survey as well as a detailed overview of the existing test facility, indicating potentials for improvement with the introduction of the new diagnostic system. This introduction is followed by the description of the system engineering approach taken in the the scope of this work in order to facilitate the development of this complex diagnostic tool within the temporal and monetary limitations imposed on this project. The main portion of the work described in the following focuses on the development of the novel sensor, which is identified as the optimumsolution in the preceding system engineering section. With the supporting systems for sensor actuation, data collection and post-processing in place the work closes with an exemplary thruster test which derives an indirect thrust measurement from the data collected with the new system and comparing it with a measurement taken by the validated highly precise thrust balance. Good agreement between the two values is shown.Aerospace Engineerin
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
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
Development of an intrusive technique for particles collection in rockets plume
Full text linkAn intrusive technique for particles capturing in supersonic-high temperature flows to be used in solid rocket motors plume characterization is proposed. A supersonic probe for the collection of the condensed combustion products in the proximity of the rocket nozzle has been designed to handle a progressive deceleration and cooling down of the exhaust gas, aiming at preserving liquid particles from break-up. A quasy-1D gas dynamics software (POLIRocket-V2) based on the Shapiro method and normal shock wave theory, supported by a CFD investigation using the DLR TAU code, was employed for the feasibility and the design study. Preliminary cold flow tests have been performed in the VMK supersonic vertical wind tunnel at DLR in relevant flow conditions. A proofs of concept of the probe working principle and the collection methodology were studied
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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