1,721,197 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
Advanced technologies for heterodyne radio astronomy instrumentation - Part1 by A. Pavolotsky, and Advanced technologies for heterodyne radio astronomy instrumentation - Part2 by V. Desmaris
No full textWe present the advanced micro/nano technological engineering at the atomic level producing state-of-the-art epitaxial NbN thin-films on GaN buffer layers. Furthermore, we report the outstanding performance of the hot electron bolometers fabricated on epitaxial NbN thin films on GaN buffer layers. Finally we present advanced passive devices such as waveguide hybrids, IF hybrids and combiners for the realization of heterodyne THz receivers
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
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
Wideband Balanced Amplifier for Future ALMA Wideband Receivers
No full textThe new generations of ALMA receivers demand wider instantaneous IF bandwidths combined with 2SB mixer technology. As a result, the required larger fractional bandwidths of cryogenic IF amplifiers impose a trade-off between their noise temperature and input reflection matching.
Cryogenic isolators have so far been employed in all European bands of ALMA. However, ferrite isolators are already reaching their limits in terms of fractional bandwidth and further degrade the noise temperature at the edge of the band.
Balanced amplifier on the other hand are implemented in some prototype radio astronomical receivers and have the great advantage of providing larger fractional bandwidth with better overall noise performance than with an input isolator.
At the workshop, we shall present the results of the latest development in terms of cryogenic balanced amplifiers for SIS receivers with enhanced IF bandwidth and the resulting performance of wideband prototypes receivers operating at 300 GHz
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
Millimeter-wave gas spectroscopy with SiGe BiCMOS transmitters and receivers for remote sensing and metrology
No full textDiese Dissertation beschreibt die Charakterisierung von Sendern und Empfängern in SiGe BiCMOS Technologie für unterschiedliche Anwendungen im Millimeterwellenbereich. Das Ziel war, ihre Einsatzfähigkeit in zwei verschiedenen Fällen zu zeigen: Fernerkundung, z.B. von einem kleinen Satelliten aus, und Metrologie, in Form einer stabilen Frequenzreferenz. Die Leistungsfähigkeit zweier Chip-Versionen wurde untersucht. Die eine Version deckt den Frequenzbereich 200-255 GHz ab, die andere den zwischen 222-255 GHz und 444-540 GHz. Beide Versionen wurden erfolgreich für Modulationsspektroskopie von Methanol eingesetzt. Für weiterführende Messungen wurde wegen ihres niedrigeren Rauschlevels und der höheren emittierten Leistung die erste Version ausgewählt. Im Kontext der Fernerkundung wurde die Rauschtemperatur des Empfängers und seine Allan-Zeit bestimmt. In einem Laboraufbau für Emissions- und Absorptionsmessungen wurden Experimente mit gasförmigem Acetonitril durchgeführt. Aus diesen lassen sich Schlüsse für den Einsatz in einer Feldmessung ziehen. Desweiteren wurde eine Moleküluhr realisiert. Die Kurzzeitstabilität wird vom Rauschlevel und der Absorptionslinie dominiert, das Langzeitverhalten von Driften im Gesamtaufbau. Die besten Ergebnisse wurden mit Kohlenstoffmonoxid erzielt und führten zu einer Allan-Abweichung von 2.3E-11 bei t=1000 s. Dopplerfreie Spektroskopie, die für eine Verbesserung der Kurzzeitstabilität in Betracht gezogen wurde, konnte nicht erfolgreich durchgeführt werden. Für Verbesserungen wurden die folgenden Ausgangspunkte identifiziert: Für die Heterodynspektroskopie, eine bessere Trennung von internen Empfängersignalen, für die Stabilisierung, Veränderungen im Aufbau, die zu einer besseren Langzeitstabilität führen. Für beide Anwendungen sollte die Temperaturabhängigkeit der Leistungsfähigkeit untersucht werden, da Hinweise gefunden wurden, dass Kühlen oder Isolieren zu Verbesserungen führen könnten.In this thesis, SiGe BiCMOS transmitters and receivers are characterized for different applications in millimeter-wave spectroscopy. The goal is to analyze the applicability of these transmitters and receivers in two cases: Remote sensing, as for example from a small satellite, and metrology, in building a very stable frequency reference. The general performance of two versions of transmitter and receiver chips was analyzed. One is covering 220-255 GHz, the other is working at 222-270 GHz and 444-540 GHz. With both, wavelength modulation spectroscopy of methanol was successfully carried out. For further experiments, the first version was chosen due to its lower noise level and higher emitted power. For heterodyne spectroscopy for remote sensing, the noise temperature and Allan time of the receiver were analyzed and a setup for emission and absorption spectroscopy was built. With acetonitrile as trial gas, experiments were performed which allow predictions for the performance in mission operation. To build a stable frequency reference, a stabilization setup was developed to lock the transmitter to a rotational absorption line (molecular clock). The short- and long-term stability were analyzed. The short-term performance is limited by the system's noise and the parameters of the absorption line, whereas the long-term stability is mostly governed by drifts that stem from details of the setup. Best results with carbon monoxide showed an Allan deviation of 2.3E-11 at t=1000 s. Doppler-free spectroscopy, which was considered as an option to improve the short-term stability, could not be performed successfully. Starting points for improvement of the performance were identified for heterodyne spectroscopy in better isolation of internal receiver signals from each other. For the molecular clock, modifications in the setup are expected to improve the long-term stability considerably. In both cases, the temperature dependence of the performance is worth a deeper analysis
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