1,721,023 research outputs found
Influenza del gioco meccanico angolare nelle vibrazioni flessionali degli alberi cardanici
No full textThis work illustrates a methodology for static and dynamic analysis of the cardanic shaft flexural behaviour; this method even takes into account the mechanical backlash of the linear compensation device. The static analysis results regarding the effects, due to the backlash, on the axes geometry of the broached and spline shafts, which make the intermediate shaft, are at first illustrated. An angular speed range that guarantees a pressure distribution without critical areas, between the broached shaft and the spline one, is afterwards specified. A model for dynamic analysis of the flexural vibrations that is capable of estimating the deflection and bending moment diagram, is furthermore developed. The way in which this model can forecast the limits of the above-mentioned speed range is finally described
Isotropy Conditions for Measurement Manipulators in a Biomechanical Application by means of the Lie Product
No full textIn this paper static isotropy in manipulators is studied in order to improve performances in a class of measurement robots dedicated to some biomechanical application. The Authors propose an approach based on the use of the GSLT (General System Logical Theory) and of the Lie Product applied to the compliance matrix. Null values of the Lie Product will be related to the isotropic configurations for the manipulators, provided that a proper variation operator is identified. Indeed, the Lie Product turns out to be a simple performance index, since it gives a real measure of how a configuration is near to isotropy. The approach appears promising not only for the analysis, but also for robot synthesis
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
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