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Hydrodynamics and morphodynamics of a tidal inlet: preliminary two-dimensional depth-averaged modelling
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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
Variable resolution for SPH in three dimensions:Towards optimal splitting and coalescing for dynamic adaptivity
Full text linkAs smoothed particle hydrodynamics (SPH) becomes increasingly popular for complex flow analysis the need to improve efficiency particularly for 3-D problems is becoming greater. Automatic adaptivity with variable particle size is therefore desirable. In this paper, a novel 3-D splitting and coalescing algorithm is developed which minimizes density error while conserving both mass and momentum using a variational principle. Accuracy is increased in refined areas unaffected by coarser particle distributions elsewhere. For particle splitting, the key criteria are the number of split (daughter) particles, their distribution, spacing and kernel size. Four different splitting arrangements are investigated including a cubic stencil with 8 particles, a cubic stencil with an additional 6 located at the face centres, an icosahedron-shaped arrangement with 14 particles, and a dodecahedron-shaped arrangement with 20 particles where particles are located at the vertices. The error analysis also examines whether retaining a particle at the centre of the arrangement is necessary revealing that regardless of the stencil adopted, to minimize the density error a daughter particle should be placed at the same position of the original particle. The optimum configuration is found to be the icosahedron-shaped arrangement while commonly used smoothing kernels such as the cubic and quintic splines and Wendland produce similar density errors, so that the optimal refinement stencil is effectively independent of the kernel choice. A new 3-D coalescing scheme completes the algorithm such that the particle resolution can be either increased or reduced locally. The SPH splitting and coalescing scheme, is tested with Poiseuille flow showing negligible loss of convergence accuracy in the refined area and the lid driven cavity for a wide range of Reynolds number showing good agreement with reference solutions again with local accuracy defined by particle distribution.</p
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
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