1,721,018 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
WxFUSION - Weather Forecast User-oriented System Including Object Nowcasting
No full textPresentation on the concept and first results of the Weather Forecast User Oriented System Including Object Nowcasting (WxFUSION), an integrated system using observations and numerical model data to nowcast and forecast weather hazards for air traffic
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
Die DLR Gewitter-Nowcasting Tools Cb-TRAM und Rad-TRAM
No full textVorstellung der DLR Gewitter-Nowcatsingwerkzeuge Cb-TRAM und Rad-TRAM gegenüber Luftverkehrsunternehme
Verbesserte Sicherheit für den Flugverkehr durch boden- und satellitengestütze Wetterinformationssysteme
No full textToday’s weather information for pilots on thunderstorm conditions on their flight is insufficient. Weather charts provided by the World Area Forecasting Centres and taken onboard by pilots before take-off are based on forecasts of large scale weather models which are initialized only four times a day. These models have high predictive skill in forecasting the large scale weather situation, i.e., the distribution of high and low pressure areas together with synoptic scale fronts for the next days and precipitation for about one day in advance. Thunderstorms however, whose time and space scales typically range from tens of minutes up to an hour and from hundreds of meters to some kilometres in diameter, cannot be deterministically forecast by these models.
For the instantaneous picture in flight, pilots have information on thunderstorm activity through onboard radar equipment. The radar provides a good indication on thunderstorm activity within the close range ahead of the aircraft, about 50 miles or so, provided there is precipitation within the convective up-droughts, strong enough to give radar returns. However, when precipitation cells are large and intense, or several cells lie behind one another, the radar pulses are strongly attenuated. In such cases information about the situation is incomplete which makes it difficult for pilots to choose a proper path around thunderstorm cells or through a thunderstorm line. In addition there are cases where thunderstorm cells are just about to develop with weak or no returns on the radar, yet they can produce convective turbulence which can propagate to levels above the developing cells. In that case the aircraft might experience sudden turbulence without any forewarning.
In contrast to onboard radar, remote sensing by ground based radar, satellite and lightning detectors can provide a more complete picture of the thunderstorm situation. Ground based systems have been developed which use this data to inspect cells from above, below and multiple viewing angles thereby being able to provide a more complete picture of the thunderstorm situation. Thunderstorms can be detected from satellite observations due to their cold cloud tops and characteristic cloud properties; the precipitation they produce can be detected by radar and lightning discharges by lightning detectors. For the middle European area data retrieved by the Meteosat Second Generation satellites operated by EUMETSAT, radar data from the European radar network organized by the national weather services and lightning data from networks operated by EUCLID and LINET can be used in expert systems to deduce and nowcast hazards brought about by thunderstorms. Utilising these sources of data a thunderstorm weather information and management system - Cb WIMS - was set up within the course of the FLYSAFE project, which was part funded by the European Commission. CB-WIMS has successfully been employed and demonstrated during flight trials carried out in summer 2008 over Central Europe.
The aim of the paper is to demonstrate that the information provided by such a system could help pilots in gaining a better overview of the weather situation as compared to what can be provided by nowadays onboard systems. This in turn could help pilots in decision making, e.g. which route to take when passing through a thunderstorm line. For the study a number of aircraft accidents and incidents related to thunderstorm activity has been selected for demonstrating the usefulness of such a ground based weather information system. In each case, thunderstorm positions as detected by the ground based system are compared with actual aircraft positions and tracks where known. Finally, the possible up-link of the ground-based weather information to the cockpit is addressed by referring to ongoing and future activities in this direction
Höhere Sicherheit durch bessere Wetterinformation für den Flugverkehr
No full textNeuartige Verfahren zur Auswertung von Satellit- und Radardaten ermöglichen die zeitnahe Erkennung und kurzfristige Vorhersage von Gewittern. Am Beispiele vergangener Flugvorfälle mit Gewittern wird ausgeführt, wie der Einsatz dieser Verfahren dazu hätte helfen können um Piloten und Air Traffic Management rechtzeitig vor der Gewittergefahr zu warnen und ev. eine andere Flugroute zu wählen
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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