1,720,957 research outputs found
Entropy Theory Application for Flow Monitoring in Natural Channels
No full textA quick and accurate determination of flow passing through a river section is fundamental for a large number of engineering applications such as flood forecasting models and the real time water resources management. Velocity is one of the basic variables for open channel flow and its variation across a section is described by the velocity profile distribution. This aspect has been also investigated through a probabilistic approach based on the entropy concept, which also expresses the mean flow velocity as a linear function of the maximum velocity through a dimensionless entropy parameter M. Therefore, the entropic relationship between the mean flow velocity and the maximum velocity has been investigated here for nine gauged river sections. Five of them are located in Italy and the other four in Algeria. Based on the flow velocity measurements sample of each site, the robustness of the linear entropic relationship has been proved. The entropic parameter, M, which characterizes the relationship, has been found uniform for seven river sites with a value in the range of 2.1 – 2.5. For two river sites the value has been lower and equal to -0.22 and 0.33, respectively. As this parameter is fundamental for addressing the flow velocity measurements at equipped river sites, the morphological characteristics of river reaches where the gauged sections are located have been investigated and identified in terms of Rosgen classification. The seven gauged sections with uniform M value have been found belonging to the same stream classification, i.e. type C, except one located in Algeria which is type D. The other two with different M values have been ascribed at different types. The analysis, although preliminary, allows foreseeing new developments in the application of the entropy approach addressed to quantify high flow discharges, especially in new gauged river sites where M is unknown
Applicability of entropic velocity distributions in natural channel
No full textFour different approaches to describe velocity profiles along verticals in natural channels and based on the entropic model have been investigated. Three of them consider a modified entropic formulation of velocity profiles, using different estimations of the entropic parameter, M. The fourth one uses the entropic formulation assuming a parabolic distribution of maximum velocities in flow area. Methods have been thoroughly investigated for low and high flow also for sampling condition of velocity points in the upper portion of the flow area. Two equipped hydrometric sites located along the Basento River, in Southern Italy, have been used as case study. A set of velocity measurements have been selected and methods reliability has been investigated in terms of percentage errors in estimating the mean velocity along each sampled vertical. It was found that the entropic model based on parabolic approach performed with similar accuracy of the other ones, showing that it can be conveniently applied for high flow conditions, when velocity points sampling is difficult in lower flow area
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
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
- …
