1,720,973 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
Particle identification algorithms for the Panda Barrel DIRC
No full textThe innovative Barrel DIRC (Detection of Internally Reflected Cherenkov light) counter will provide hadronic particle identification (PID) in the central region of the PANDA experiment at the new Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany. This detector is designed to separate charged pions and kaons with at least 3 standard deviations for momenta up to 3.5 GeV/c covering the polar angle range of 22-140 degree. An array of microchannel plate photomultiplier tubes is used to detect the location and arrival time of the Cherenkov photons with a position resolution of 2 mm and time precision of about 100 ps. Two reconstruction algorithms have been developed to make optimum use of the observables and to determine the performance of the detector. The "geometrical reconstruction" performs PID by reconstructing the value of the Cherenkov angle and using it in a track-by-track maximum likelihood fit. This method mostly relies on the position of the detected photons in the reconstruction, while the "time imaging" utilizes both, position and time information, and directly performs the maximum likelihood fit using probability density functions determined analytically or from detailed simulations. Geant4 simulations and data from the particle beams where used to optimize both algorithms in terms of PID performance and reconstruction speed. We will present current status of development and discuss advantages of each algorithm
DIRC detector upgrade for the GlueX experiment
No full textThe upgrade of the GlueX experiment at Jefferson Lab with a DIRC (Detection of Internally Reflected Cherenkov light) counter will significantly improve the particle identification (PID) capabilities in the forward region of the detector by providing clean π/K separation for momenta up to 4 GeV/c. The GlueX DIRC combines four bar boxes from the decommissioned BaBar DIRC detector with new compact photon cameras based on the SuperB FDIRC concept. Two reconstruction algorithms were developed to optimize the hadronic PID performance. Benchmark physics channels of cleanly identified exclusive events will be used for DIRC performance studies. The DIRC counter will be installed into the GlueX experiment during the winter 2018/2019 shutdown and commissioned with beam in February 2019. We will discuss the status of the GlueX DIRC detector and first impressions from the commissioning run
DIRC-based PID for the EIC Central Detector
No full textThe physics program for the Electron-Ion Collider (EIC) detector requires charged Particle Identification (PID) (e/π, π/K, K/p) over a wide momentum range. It is expected that the PID system will need to include one or more Cherenkov counters to achieve this goal. A radially compact DIRC (Detector of Internally Reflected Cherenkov light) counter is an attractive option in barrel region.The ongoing R&D investigates ways to extend the momentum coverage of a DIRC counter for the EIC detector beyond the current state-of-the-art with clean π/K separation up to at least 6 GeV/c. Possible design improvements include a complex imaging system, comprising multi-component spherical lenses, a compact fused silica expansion volume, and multi-anode sensors with smaller pixels, providing fast single-photon timing in high magnetic fields, a time-based PID algorithm, and chromatic dispersion mitigation.We will discuss the current status of the design studies with Geant simulations, improvements to the time-based imaging reconstruction, and the results of prototype tests with particle beams at CERN
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