1,721,096 research outputs found
Determining Probability Distribution of Hillslope Peak Discharge by Using an Analytical Solution of Kinematic Wave Time of Concentration.
No full textHillslope hydrology is fundamental for understanding the flood phenomenon and for evaluating the time of
concentration. The latter is a key variable for predicting peak discharge at the basin outlet and for designing urban
infrastructure facilities. There have been a multitude of studies on the hydrologic response at the hillslope scale,
and the time of concentration has been derived for different approaches. One approach for deriving hillslope
response utilizes, in a distributed form, the differential equations of unsteady overland flow, specifically developed
at the hydrodynamic scale, in order to account for the spatial heterogeneity of soil characteristics, topography,
roughness and vegetation cover on the hillslope. Therefore, this approach seemingly mimics the complete
hydraulics of flow. However, the very complex patterns generated by spatial heterogeneity can cause considerable
error in the prediction even by very sophisticated models. Another approach that directly operates at the hillslope
scale is by averaging over the hillslope the soil hydraulics, the topography, and the roughness characteristics. A
physically-based lumped model of hillslope response was first proposed by Horton (1938), under the assumption
that the flow regime is intermediate between laminar and turbulent regimes (transitional flow regime), by applying
the mass conservation equation to the hillslope as a whole and by using the kinematic wave assumption for
the friction slope (Singh, 1976, 1996). Robinson et al. (1995) and Robinson and Sivapalan (1996) generalized
Horton’s approach, suggesting an approximate solution of the overland flow equation that is valid for all flow
regimes. Agnese et al. (2001) derived an analytical solution of a nonlinear storage model of hillslope response that
is valid for all flow regimes, and the associated time of concentration.
Recently, the well-known kinematic wave equation for computing the time of concentration for impervious
surfaces has been extended to the case of pervious hillslopes, accounting for infiltration. In particular, an analytical
solution for the time of concentration for overland flow on a rectangular plane surface was derived using the
kinematic wave equation under the Green-Ampt infiltration (Baiamonte and Singh, 2015). The objective of
this work is to apply the latter solution to determine the probability distribution of hillslope peak discharge by
combining it with the familiar rainfall duration-intensity-frequency approach
Single versus multi species indicators in environmental modelling: a review [CD-ROM]
No full textThe use of biological responses in environmental modelling, also referred to as biomonitoring, mainly involves indicator species or communities those accumulate pollutants in their tissues from the surrounding environment, thus reflect the environmental conditions. Despite the progress made through research activities in detecting biological changes in these organisms at various levels i.e. macromolecular, cellular within individual organisms and in communities, constraints with conventional data analysis methods in exactly assessing an environmental pollution and its real cause led ecologists to experiment with emerging technologies. The recent use of artificial neural networks (ANNs), especially self-organising map (SOM) and evolving SOM techniques to analyse multi dimensional data sets provide a means to analyse community dynamics and is elaborated upon with a case study from northern New Zealand
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
Spatial structure of internal tidal waves generated on weak topographies
No full textThe generation of internal gravity waves by barotropic tidal flow passing over a two-dimensional topography is investigated. Rather than calculating the conversion of tidal energy, this study focuses on delineating the geometric characteristics of the spatial structure of the resulting internal wave fields (i.e., the configurations of the internal beams and their horizontal projections) which have usually been ignored. it is found that the various possible wave types can be demarcated by three characteristic frequencies: the tidal frequency, wo; the buoyancy frequency, N; and the vertical component of the Coriolis vector or earth's rotation.f. When different possibilities arising from the sequence of these frequencies are considered, there occur 12 kinds of wave structures in the full 3D space in contrast to the 5 kinds identified by the 2D theory. The constant wave phase lines may form as ellipses or hyperbolic lines on the horizontal plane, provided the buoyancy frequency is greater or less than the tidal frequency. The effect that stems from the consideration of the basic flow is also found, which not only serves as the reason for the occurrence of higtter harmonics but also increases the wave strength in the direction of basic flow. (C) 2009 Elsevier B.V. All rights reserved
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
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