1,720,994 research outputs found
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
Ceramic Tile Surfaces in Acid Environment: Study on the Topographic, Microstructural and Mechanical Changes
No full textGlazed ceramic tiles are characterized by a good chemical durability excepting in highly alkaline and acid environment. A continual use of cleaning agents with a basic or acid pH on ceramic flooring could give rise to a lowering of mechanical performances due to corrosion of crystalline phases more than the amorphous phase. In the present work, several glazed tile surfaces characterized by different microstructures (amorphous and partially crystallized) were considered. In order to better understand the mechanism responsible of the surface tiles ageing, the working surfaces, before and after chemical etching, were analysed from topografic, microstructural and mechanical point of view, Results showed that it is possible to correlate microstructural differences of ceramic surfaces before and after a chemical etching, with their physical-mechanical characteristics
Effect of porosity on the elastic properties of porcelainized stoneware tiles by a multi-layered model
No full textPorcelainized stoneware represents a leading product in the world market of ceramic tiles, thanks to its relevant bending strength (with respectto other classes of tiles) and extremely low water absorption: these properties derive from its really low content of residual porosity. Nevertheless,an accurate investigation of the cross section of a porcelainized stoneware tile reveals a non-uniform distribution of the residual pores through thethickness, which results in a spatial gradient of properties. Porcelainized stoneware, therefore, may be looked at as a functionally graded material.In the present research, commercial porcelainized stonewares were analysed in order to define the effect of the residual porosity and its spatialdistribution on the mechanical properties of tiles. Polished cross sections of porcelainized stoneware tiles were investigated by optical and scanningelectron microscopy in order to define the content and distribution of residual pores as a function of distance from the working surface. For eachporcelainized stoneware, the local elastic properties of the ceramic matrix were measured by a depth-sensing Vickers micro-indentation technique,then the so-obtained microstructural images and elastic properties were used to model the stoneware tile mechanical properties. In particular, thecross section of each tile was described as a multi-layered system, each layer of which was considered as a composite material formed by a ceramicmatrix and residual pores. The elastic properties of each layer were predicted by applying analytical equations derived from the theory of compositematerials and, as a new approach, by performing microstructure-based finite element simulations. In order to validate the proposed multi-layeredmodel and identify the most reliable predictive technique, the numerical results were compared with experimental data obtained by a resonancebasedmethod
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