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A new shoreline boundary condition for a highly nonlinear 1DH Boussinesq model for breaking waves
No full textIn order to model the wave motion and, in turn, the flow, within the nearshore region, in the last decades the derivation and the application of Boussinesq type of models have been extensively investigated.
Nevertheless, in the framework of such depth integrated numerical models, the problems of modeling wave breaking and moving onshore boundary at the shoreline are not trivial and several approaches have been proposed to overcome these limits.
In the present work an effort toward a more physical based model of the surf and the swash zone has been accomplished. In particular, starting from the work of Musumeci et al. (2005), a new model of the shoreline boundary condition has been implemented. The shoreline boundary condition is developed with a fixed grid method with a wet-dry interface and with a linear extrapolation (Lynett et al. 2002) near the wet-dry boundary has been used and coupled with the shoreline equations (Prasad and Svendsen, 2003). To validate the model a classical test which adopts a monochromatic wave train over a plane beach has been performed. In particular the analytical solution derived by Carrier and Greenspan (1958) has been used for comparison.
The comparison between the analytical and numerical horizontal shoreline movements, gives a fairly good agreement. Other tests on breaking of solitary waves have been performed. The solitary wave shoreline oscillation is investigated by comparison with the experimental tests by Synolakis (1986). The results are in fairly good agreement with the experimental data
A shoreline boundary condition for a highly nonlinear Boussinesq model for breaking waves
No full textA physically based strategy was used to model swash zone hydrodynamics forced by
breaking waves within a Boussinesq type of model. The position and the velocity of the shoreline were
determined continuously in space by solving the physically based equations of the shoreline motion;
moreover, a fixed grid method, with a wet-dry interface, was adopted for integrating the Boussinesq
model. The numerical stability of the model was improved by means of an extrapolation method. To
validate the proposed methodology, the classical analytical solution for the shoreline motion of a
monochromatic wave train over a plane beach was considered. The comparison between the analytical
and numerical horizontal shoreline movements provided a very good agreement. Several other tests on
the run-up of non-breaking and breaking waves were performed as well. These tests showed that the
proposed model was always in fairly good agreement with the experimental data, even in complex
hydrodynamic situations like those forced by breaking solitary waves. In particular, in comparison
with other state-of-the art shoreline models, in all the analyzed cases the proposed model allowed
much better predictions of the shoreline velocity to be obtained
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
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