1,721,087 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
Sentinel-5p/TROPOMI SO2 Layer Height dataset covering the Raikoke volcanic eruption 2019
No full textSentinel-5p/TROPOMI SO2 Layer Height product generated by DLR as part of the INPULS project using the retrieval algorithm developed in the framework of the ESA Sentinel-5p Innovations: SO2 LH (S5P+I: SO2LH) project
The dataset contains SO2LH results for the timeframe 2019-06-22 until 2019-07-30 covering the eruptive period of the Raikoke volcanic eruption. This dataset was used as input for the paper of Inness et al. "The CAMS volcanic forecasting system utilizing near-real time data assimilation of S5P/TROPOMI SO2 retrievals" (2021, submitted to GMD)
The dataset contains modified Copernicus Sentinel data processed by DL
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
S5P+I SO2 Layer Height Product User Manual
No full textThis Product User Manual (PUM) describes the technical characteristics of the S5p/TROPOMI SO2 LH L2 geophysical data product that is needed for efficient and correct use of the data contained and the structure of the L2 datafile is described. A description of the related retrieval SO2 layer height algorithm can be found in the S5P+I SO2LH ATBD
Strahlungstransport in der Exosphäre des Saturnmondes Titan
No full textDiese Arbeit beschäftigt sich mit der Wasserstoffverteilung in der Exosphäre des Saturnmondes Titan. Grundlage dieser Arbeit sind Messungen des HDAC Instrumentes (Hydrogen Deuterium Absorption Cell), welches an Bord der Cassini- Raumsonde das D/H Verhältnis direkt durch die Messung der Emissionslinien von atomarem Wasserstoff und Deuterium im Ultravioletten bei 121.567 nm bzw. 121.533 nm bestimmen sollte. Mit HDAC wurden am 26. Dezember 2005 beim neunten Titanvorbeiflug der Cassini-Sonde Messungen vorgenommen. Leider konnte die Menge an Deuterium in der Absorptionszelle nicht bestimmt werden, sodass HDAC seinen vorgesehen Zweck nicht erfüllen konnte. Die Menge an Wasserstoff in der Zelle ist jedoch bekannt, so dass zumindest die Wasserstoff-Lyman-Alpha Messung verwendet werden kann, um Titans Exosphäre zu untersuchen. Ziel dieser Arbeit war es, die HDAC Messungen zu simulieren und somit Rückschlüsse auf die Exosphäre von Titan ziehen zu können, wie z.B. die Verteilung von atomarem Wasserstoff in der Exosphäre. In dieser Arbeit wurde ein Modell der Titanexosphäre entwickelt, welches atomaren Wasserstoff und Methan berücksichtigt. Für das Exosphärenmodell wurden zwei unterschiedliche Dichtemodelle gewählt, welche die Dichteverteilung von Wasserstoff in der Exosphäre unterschiedlich berechnen und insbesondere in der unteren Exosphäre voneinander abweichen. Der Strahlungstransport durch die Modell-Exosphäre wurde mit Hilfe der Monte-Carlo-Methode gelöst. Detaillierte Strahlungstransportrechnungen haben gezeigt, dass die HDAC Messungen mit Dichteprofilen aus beiden Dichtemodellen reproduziert werden können. Dabei konnte gezeigt werden, dass das von HDAC gemessene Signal aus Höhenschichten 2000 km oberhalb der Exobase stammt. Die mit den Dichtemodellen bestimmten Exobasendichten unterscheiden sich dabei um einen Faktor vier. Somit konnte keine Aussage darüber getroffen werden, welches Dichtemodell die HDAC Messung am besten beschreibt. Dennoch liegen die bestimmten Exobasendichten im Bereich der in der Literatur zu findenden Werte. Beruhend auf den Ergebnissen dieser Arbeit wird HDAC im Jahr 2010 bei zwei weiteren Titanvorbeiflügen erneut verwendet werden, und somit noch genauere Daten für die Bestimmung der Exosphärendichte und Temperatur liefern. Strahlungstransportrechnungen für diese Vorbeiflüge wurden ebenfalls in dieser Arbeit durchgeführtThis work focuses on the distribution of atomic hydrogen in the exosphere of Saturn’s moon Titan. This work is based on measurements performed by the “Hydrogen Deuterium Absorption Cell” (HDAC) aboard the Cassini spacecraft, that should directly determine the D/H ratio from the UV emission of atomic hydrogen and deuterium at 121.567 and 121.533 nm, respectively. HDAC measurements were performed on December 26, 2005 during the ninth Titan flyby of the Cassini orbiter. Unfortunately the amount of deuterium in the absorption cell could not be determined. Thus, the purpose, HDAC was designed for could not be achieved. For this reason, HDAC has performed measurements only once. However, the amount of atomic hydrogen in the absorption cell is well known, hence the data using only the hydrogen cell can be used in order to investigate Titan’s exosphere. This work aims at simulating the HDAC measurements performed in order to investigate Titan’s exosphere, e.g. to determine the distribution of atomic hydrogen. A model of Titan’s exosphere including atomic hydrogen and methane has been developed and the transfer of solar radiation is calculated in order to simulate the HDAC measurements. The radiative transfer is solved using the Monte Carlo method. For the exospheric model, two different atomic hydrogen density distributions were applied, which determine the distribution in the exosphere by different approaches. Density profiles calculated by both models mainly differ in the lower exosphere. It was found that the HDAC measurements can be fitted using density profiles calculated by both exospheric density distribution models for the radiative transfer calculations. Detailed investigations however showed that the signal measured by HDAC originates at much higher altitudes of about 2000 km above the exobase. Nevertheless the best fitting atomic hydrogen exobase densities of both models differ by a factor of 4. A strong noise pattern was found in the measurements avoiding a more accurate determination of the atomic hydrogen distribution in Titan’s exosphere. However, the inferred exobase densities are in the range of literature values. As a result of this work, HDAC will be used again during two future flybys in 2010, providing more accurate measurements for the determination of densities and temperatures in Titan’s exosphere
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