1,720,995 research outputs found
USING OPEN SOURCE SOFTWARE AND OPEN STANDARDS FOR OPERATING ROBOTIC TELESCOPES
No full textThe University of G¨ottingen, the McDonald Observatory of the University of Texas at Austin, and the South African Astronomical Observatory (SAAO) operate two robotic telescopes called MONET at McDonald Observatory in Fort Davis, Texas (MONET/North), and at the SAAO in Sutherland, South Africa (MONET/South). After problems with our original observation control system and some difficulties with another one, we decided to build our own system, initially providing only the minimally required functionality, but allowing for easy extensibility. A decision was made to build on open standards and open source software only, so that we can use existing and well-tested technologies. In this paper we will describe our efforts to implement such an open observation control system using HTTP and XMPP. Furthermore, we will discuss possibilities for connecting multiple telescopes via VOEvents and RTML
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
A long-term optical and X-ray ephemeris of the polar EK Ursae Majoris
No full textAims. We searched for long-term period changes in the polar EK UMa using
new optical data and archival X-ray/EUV data.
Methods. An optical ephemeris was derived from data taken remotely with the
MONET/N telescope and compared with the X-ray ephemeris based on
Einstein, ROSAT, and EUVE data. A three-parameter fit to the
combined data sets yields the epoch, the period, and the phase offset
between the optical minima and the X-ray absorption dips. An added
quadratic term is insignificant and sets a limit to the period
change.
Results. The derived linear ephemeris is valid over 30 years and the common
optical and X-ray period is P = 0.0795440225(24) days. There is no
evidence of long-term O-C variations or a period change over the
past 17 years (ΔP = -0.14 ± 0.50 ms). We suggest that the
observed period is the orbital period and that the system is tightly
synchronized. The limit on ΔP and the phase constancy of the
bright part of the light curve indicate that O-C variations of the
type seen in the polars DP Leo and HU Aqr or the pre-CV NN Ser do
not seem to occur in EK UMa. The X-ray dips lag the optical minima by
9.5° ± 0.7° in azimuth, providing some insight into the accretion
geometry
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
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
- …
