1,721,107 research outputs found
L’Impero e l’organizzazione del consenso: la dominazione napoleonica negli Stati Romani, 1809-1814
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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
Dynamic properties of asymmetric discrete vortex-flow transistors
No full textThe dynamic properties of discrete vortex-flow transistors (DVFTs) comprised of a parallel array of ten Josephson junctions with asymmetric bias-current configurations have been studied numerically. Using parameters typical of high-temperature superconductor junctions at liquid-nitrogen temperatures, we show explicitly that the asymmetric-inline geometry, while it has the advantage of large (low-frequency) current gain (of order 50) and peak transresistance (of order 10 ), is inherently limited by slow vortex transit times (of order 100 ps) which result from the absence of Lorentz forces on vortices moving in the structure. We also explain the extremely small dynamic range of the high-gain regime seen in the simulations here and observed experimentally in the literature. As the device symmetry is increased, faster transit times and a significant increase in dynamic range are observed. These results have direct impact on the feasibility of these devices as high-frequency amplifiers
Study of the protection system for Nb3Sn cos-theta NED dipole
No full textThe Next European Dipole (NED) Collaboration has the scope to promote the study and development of a high magnetic field (15 T conductor peak field) and large aperture (88 mm) dipole magnet aimed at LHC upgrade and at the next generation colliders. Among different configurations, a classical cosine-theta solution is considered. This magnet will be based on a high current density (Jc around 1500 A/mm2 @ 15 T, 4.2 K in the noncopper section) Nb3 Sn superconductor, and will have a high stored magnetic energy (1.8 MJ/m, i.e. 8 times higher than for one LHC dipole), that makes the magnet protection extremely critical. In this paper we have investigated the quench propagation assuming different dump resistance values and operating conditions (quench heaters efficiency, delay time for the Quench Detector System), in order to optimize the protection system in terms of peak temperatures in the coils and maximum voltage drops. The study is performed by using two quench propagation codes, which exploit different approaches, in order to further validate our conclusion
Three Terminal HTc Vortex Flow Transistors: Optimisation of the Device Geometry Employing Bicrystal Grain-Boundary Josephson Junctions
No full textWe have numerically studied the static and dynamic behavior of a three terminal vortex-flow transistor based on a parallel array of Josephson junctions. We explicitly show advantages and disadvantages for different device geometric configurations, systematically changing the symmetry of the bias-current distribution. Using parameters typical of high-temperature superconducting junctions at 77K, we have analysed for each configuration the dependence of the critical current on the control current, and the voltage-current curves. We have calculated gain and transresistance for different bias conditions, and explained the numerical results in terms of the vortex dynamics in the array. This study allows us to establish limits for the operating regime of these devices when used as high-frequency amplifiers.
Read More: http://www.worldscientific.com/doi/abs/10.1142/S021797929900126
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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