1,720,955 research outputs found
Development and application of high-order discontinuous CVFEM algorithms
No full textThe discontinuous control-volume finite-element method is applied to the one-dimensional advection-diffusion equation and
validated on relevant test cases. The technique merges the features of the classical finite-volume method, as robustness and local
conservation properties [1], with those of the discontinuous Galerkin finite-element method, known for the capability of handling
large gradients or discontinuities with high accuracy [2]. On the other hand, most finite-volume methods attain relatively low
orders of spatial accuracy and resolution characteristics, particularly on unstructured meshes. To achieve high-order accuracy,
the proposed technique adopts polynomial shape functions of any degree as in spectral finite-element methods [3]. In many
applications high resolution is not needed in the whole domain, which results also in a loss of computational resources. We thus
apply an automatic p-refinement technique which adapts the polynomial order at element level, according to the local behavior
of the computed solution. Element-wise p-adaption can be easily achieved with discontinuous Galerkin methods, where the
inter-element continuity is imposed in weak form
Discontinuous control-volume/finite-element method for advection-diffusion problems
No full textThe discontinuous control-volume/finite-element method is applied to the
one-dimensional advection-diffusion equation. The aforementioned methodology
is relatively novel and has been mainly applied for the solution of
pure-advection problems. This work focuses on the main features of an accurate
representation of the diffusion operator, which are investigated both by
Fourier analysis and numerical experiments. A mixed formulation is followed,
where the constitutive equation for the diffusive flux is not substituted into
the conservation equation for the transported scalar. The Fourier analysis of
a linear, diffusion problem shows that the resolution error is both dispersive
and dissipative, in contrast with the purely dissipative error of the traditional
continuous Galerkin approximation
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
High-order methods for computational fluid dynamics
Full text link2010/2011In the past two decades, the growing interest in the study of fluid flows involving discontinuities, such as shocks or high gradients, where a quadratic-convergent method may not provide a satisfactory solution, gave a notable impulse to the employment of high-order techniques.
The present dissertation comprises the analysis and numerical testing of two high-order methods. The first one, belonging
to the discontinuous finite-element class, is the discontinuous control-volume/finite-element method (DCVFEM) for the advection/
diffusion equation. The second method refers to the high-order finite-difference class, and is the mixed weighted non-oscillatory scheme (MWCS) for the solution of the compressible Euler equations. The methods are described from a formal point of view, a Fourier analysis is used to assess the
dispersion and dissipation errors, and numerical simulations are conducted to confirm the theoretical results.XXIV Ciclo198
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
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