1,720,960 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
Comprehensive Analysis of a Slow Wave Structure for an X-band MILO
No full textMagnetically Insulated transmission Line Oscillator (MILO) is a relatively new
High Power Microwave (HPM) device that has recently received increasing attention because it
does not require an external magnetic ̄eld and can generate gigawatt (GW) of power from L to
Ku bands. Furthermore, it is a compact and lightweight tube and can operate at low impedance
(» 10 ). The most signi ̄cant element in a magnetically insulated transmission line oscillator
(MILO) is a slow wave structure (SWS) in which the interaction between the RF ̄eld and par-
ticles occurs. This study aimed to design an SWS for an X-band MILO using a High-Frequency
Structure Simulator (HFSS) and Particle in Cell (PIC) Simulator (CST-PS). HFSS was used to
obtain the structure's dispersion relation and investigate the resonant mode frequencies through
EigenmodeSolver. Previous investigations demonstrate that a MILO oscillates in the 1⁄4-mode,
which is the spatial harmonic associated with the SWS with the highest Q. The ̄eld distri-
bution associated with this mode produces the strongest coupling to the electron °ow. In our
studies, parameter optimization was investigated, and particular attention was focused on the
phenomenon of mode competition observed during di®erent simulations. The simulations dis-
played remarkable performance in sizes and weight terms and the potential to produce very high
output power. Dispersion diagrams will be shown, highlighting the interaction between modes
propagating in the structure and beamline as the input voltage varies. An X-band MILO with
the simulated SWS was designed, and a PIC simulation was done to con ̄rm our proper design. A
pulse signal of 500 kV and 100 ns pulse length in PIC simulations generate the relativistic beam.
TEM mode and high-order modes are evaluated. A peak power of 450MW and frequency of
9.4 GHz is observed. Conclusions and possible future developments will be discussed
Multiphysics Analysis of High-power Vacuum Feedthrough for DTT ICRH System
No full textIn the framework of the Divertor Tokamak Test (DTT) facility, which aims at the validation of an integrated solution for the power exhaust moving to the DEMOnstration power plant (DEMO), an Ion Cyclotron Resonance Heating (ICRH) system is under development. Its final configuration, which comprises two independent modules, shall couple 6MW to the DTT
plasma, in a pulsed regime (pulse length 50 s, duty cycle 1.4%), in the 60-90MHz frequency range. The Vacuum Feedthrough (VFT), usually made with one or two alumina windows, assures the reliable separation between the pressurized Main Transmission Line (MTL) and Vacuum Transmission Line (VTL) sections, which is located close to the plasma-facing antenna. It is one of the most critical components of the ICRH system because it must protect the tokamak
vacuum and withstand a high RF voltage in a resonant transmission line (RTL) based on rigid coaxial cable. Results of RF, thermodynamic, and mechanical simulations of RTLs, constituted by an impedance transformer, an RF divider (T-junction), and two output branches, each with a VFT, are reported.
In our simulations, the effective antenna impedance is substituted with an equivalent resistive load (Rs), representing the coupling resistance locating the RTL outputs in a voltage node.
Thermodynamic and mechanical simulations of matched RTLs, with two windows for each branch, were conducted in the worst condition, i.e., imposing the maximum working frequency (90 MHz) and the minimum value of Rs (0.5 Ohm). In all analyses, an RF power of 1.2MW (600kW each VFT) for a pulse of 50 s has been injected into the RTL. VFTs with conical and disk geometry types with Alumina 99 windows were studied.
Considering only the unforced convection of the outer conductor, significant temperature and thermal stresses were obtained for both window types. The conical window reaches a maximum thermal stress of 140MPa, more than half of the Ultimate Tensile Strength of Alumina 99, i.e., 260MPa. Instead, given the same boundary conditions, the disk window reaches a maximum thermal stress of 35MPa. The thermal difference between the edges and the center obtained for both windows exceeds 30 degrees. The leading cause is the ohmic loss of the metals. The mechanical design is preliminary, but Multiphysics simulations already allow us to choose materials, geometry, and cooling method of VFT
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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