1,721,057 research outputs found
Analysis and modelling of surface runoff triggering debris flows
Full text linkIn the Dolomites, short-duration and high-intensity rainfalls produce abundant surface runoff in headwater catchments. These discharges often trigger debris flows on the scree slopes placed at the base of rock cliffs. With the aim to quantify the discharges delivered by these headwater catchments and associated rainfalls, we built a measuring facility at the outlet (elevation 1770 m a.s.l.) of a rocky channel incised on the Dimai Peak, near Cortina d'Ampezzo (Belluno province) in the Venetian Dolomites (North Eastern Italian Alps). The channel delivers surface runoff gathered by a small impervious headwater catchment (area ~0.032 km^2, average slope ~320%). The facility consists of a monitoring station equipped with a rain gauge, and trapezoidal-shape waterproof basin, closed by a sharp-crested weir. The recorded rainfalls allow us to verify the features that lead to runoff discharges or mass transport events. In the period 2011-2017, among the measured discharges, about fifteen runoff events were considered as significant. These observations provide a unique opportunity for improving knowledge about the hydrological response of a rocky headwater catchment. The recorded hydrographs show impulsive shapes, with a sudden raise up to the discharge peak, generally followed by a likewise rapidly decreasing tail. Furthermore, the discharges can be used to calibrate and validate hydrological models. We show that the observations can be modelled by means of a distributed hydrological model, assuming that the excess rainfall is accurately evaluated. More specifically, we show that the combination of the Soil Conservation Service Curve-Number (SCS-CN) procedure with constant routing velocities results in an underestimation of the flow peak and a delayed time of peak. Better predictions of the peak of discharge, its timing, and the impulsive shape of the hydrographs could be obtained by coupling the SCS-CN method with a simplification of the Horton equation, and simulating the routing of runoff along the channel network by means of a matched diffusivity kinematic-wave model. The reliability of the method is tested by comparing simulated and observed timings of hyper-concentrated runoff or debris flow triggering in two neighbouring dolomitic watersheds
Comparison between weather radar and rain gauges data of precipitations that triggered debris flows in the Dolomites (North Eastern Italian Alps)
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Photonic circuits monolithically integrated with silicon photodiodes
No full textWe report the realization of an Electronic-Photonic Integrated Circuit. We developed a monolithic process in which a photonic circuit is realized on top of silicon detectors, realized in the epitaxial substrate. Expoliting wedge technology, we developed two coupling methods to send the 850nm optical signal into the detectors. Ultimately, the same technology can be used to realize avalanche photodiodes operating in Geiger mode to acquire single photon resolving capability
The Use of Rain Gauge Measurements and Radar Data for the Model‐Based Prediction of Runoff‐Generated Debris‐Flow Occurrence in Early Warning Systems
Full text linkGoing 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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