1,720,976 research outputs found
COMPARISON OF TWO SIMPLE REAL-TIME FLOOD FORECAST MODELS: THE CASE STUDY OF THE PO RIVER (ITALY)
No full textThe performance of two simple models for real-time flood forecasting is investigated and compared. The first approach, named as RCM-RT, is based on the Rating Curve Model (RCM) and provides, involving only two parameters, future estimates of both discharge and water level at a river site where only the stage is monitored while the flow is known at an upstream section.
The second model, named MHBA, is described by a linear stochastic formulation of flood wave propagation and is based only on stage data.
Both models require that the forecast lead-time and the parameters are identified a-priori through a calibration phase involving different observed flood events.
The two models are tested on a long reach of the Po River (northern Italy) for several flood events. The obtained results show that both models provide an accurate forecast water level 32 hours in advance
Comparing grey formulations of the velocity-area method and entropy method for discharge estimation with uncertainty
No full textTwo methods, namely the velocity-area method and the entropy method, for assessing with uncertainty discharge measurements at gauged river sites are analysed and compared; uncertainty is represented through the grey number technique. Two different approaches for the “greyification” of both methods are presented herein. In the first approach, the uncertainty affecting each measurement used to estimate the discharge is characterized by means of a grey number: all the grey uncertainty components are then combined through the grey mathematic. In the second approach, greyification is applied to the relationship expressing the total uncertainty on the discharge measurement provided by the EN ISO 748 guidelines.
Results of the application of the proposed methods to measurement data pertaining to three different gauged sections of the Tiber river, in central Italy, show that the first greyification approach leads to a broader discharge uncertainty estimate with respect to the second. Furthermore, being the greyification approach and the flow area quantification the same, the velocity-area and entropy methods provide nearly the same estimate of the uncertainty affecting the discharge measurements, i.e. the grey discharges provided by the two methods are very similar. This testifies in favour of the entropy method, which is simpler than the other from an operative viewpoint
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
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
Investigating hydrodynamics and turbulent effects in rivers for different flow conditions using spatial complexity metrics
No full textIn non-uniform river flows, hydrodynamic features, such as gradients of velocity in flow directions, are of particular importance for explaining the abundance of aquatic habitats. Hydraulic complexity metrics referred to as M1, M2, and M3 play an important role when it comes to the analysis of habitat metrics on a 3D spatial level. Parameter M1 is proportional to the drag force experienced by an organism, parameter M2 represents how much more energy an organism must expend if it moves from the lower velocity to the higher velocity location, and parameters M3 illustrates the circulation in flow. The specific aim of the present study is to apply those parameters to characterize, under different flow conditions, the cross-sectional distribution of kinetic energy and coherent structures which are both relevant for many aquatic organisms. To this aim, laboratory data as well as field observations along Tiber River, in central Italy, were considered and the hydraulic complexity metrics were investigated in dimensionless form. On the laboratory-scale, the dimensionless parameters M1*, M2* and M3* identify the velocity gradient related to the high/low cross-sectional velocity and the high/low vorticity areas in selected cross-sections along the flume. Then, the evaluation of the parameter M2* in the horizontal plane allows to verify the relation between the localization of the high/low kinetic energy areas in the longitudinal direction. For the field-scale, the parameters were investigated, under high, moderate and low flow conditions, in a gauged site in the Tiber River. The results indicate that an aquatic organism should spend more energy where M3*, which is related to flow circulation, assumes high values. Furthermore, significant values of M1* and M2* are observed, which are linked to gradients in the cross-sectional distribution of velocity. These values are predominantly found at the river centerline for M1* and at the banks for M2*. In terms of echo-hydraulics, the results based on both laboratory and field data indicate that they are complementary, showing that for the larger magnitudes of M1 and M3, which are related to the kinetic energy and flow circulation, respectively, an aquatic organism should spend more energy in these zones. Overall, the results based on both laboratory and field studies suggest that parameters M1 and M2 are inversely linked, i.e., M1 decreased with increasing M2, while, there is no relationship between parameters M3 and M1. The findings of the present research would be of particular interest in quantifying biologically important flow patterns occurring at different spatial scales within different streams and under different flow conditions
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
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