1,721,028 research outputs found
Compton Electrons’ Tracking Within a Single Silicon Layer with Controlled-Drift Detectors
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CAMEX readout ASICs for pnCCDs
No full textFor the readout of pnCCD we developed a series of CAMEX ASICs since the early 90’s. With the advent of DEPFET PIXEL detectors the existing CAMEX readout chip was adopted for these new detectors. The actual generation of CAMEX readout chips is fabricated in a standard 5V CMOS technology with JFET option at the Fraunhofer IMS in Duisburg, Germany. To qualify the new CAMEX readout ASICs we performed several measurements including weighting function measurements, multiplexer performance and linearity as well as performance figures of the integrated bias DACs. Performance values together with the pnCCD will be shown. Further tests will also reveal the radiation performance of the ASIC. The main application of these CAMEX chips is the X-ray astronomy project eROSITA (extended Roentgen Survey with an Imaging Telescope Array). This X-ray telescope will be accommodated aboard the new Spectrum Roentgen Gamma satellite. It consists of seven parallel oriented mirror modules (Wolter-I optics) each having its own pnCCD camera in the focus. The pnCCD detector consists of 384×384 imaging pixels with 75μm size plus a frame store area. The satellite launch is planned for the year 2011.The parallel architecture of the pnCCD and CAMEX allows lownoise readout of a full 384 × 384 pixel image within ≪8 ms. Full size prototypes of the detector system are currently under test. Another application are detectors for the evolving X-ray free electron lasers, a new generation of synchrotron light sources. X-ray FEL facilities provide pulses of coherent X-ray light of high brilliance in the energy range of below 0.3 keV up to 24 keV. New prototype pnCCDs for these applications have a size of 512x1024 pixels and are readout with 8 CAMEX chips operating in parallel to archive a frame rate of up to 200Hz
Proceedings of the 10th European Symposium on Semiconductor Detectors Wildbad Kreuth, Bavaria, Germany, June 12-16, 2005
No full textGuest Editing dell'intero volume Nuclear Instruments and Methods A (vol. 568
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
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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