1,721,017 research outputs found
MODELLAZIONE NUMERICA DI ARTICOLAZIONI CEDEVOLI PER DITA DI MANI ROBOTICHE
No full textAbstract
In the present work, the flexural stiffness of a close-wound cylindrical spring for a novel joint of
robotic hands is developed by means of the finite element (FE) method. In the first step, the FE model
of the spring has been generated and verificated to guarantee its numerical accuracy. Experimental
measurements and theoretical results on close-wound springs in the same geometrical configurations
here analysed were used as benchmark to compare predictions of the developed FE models. A good
agreement was found in terms of stiffness (Nmm/rad) between numerical versus experimental and
theoretical analysis at the same rotation (90°) with a root mean square error respectively of 11% and
8%
Evaluating the Flexural Stiffness of Compliant Hinges Made with Close-wound Helical Springs
No full textAdvantages and problems related to the use of compliant hinges in articulated robotic structures are briefly discussed. A novel kind of elastic joint made with close-wound helical springs is then described. It is capable of large angular displacement so that it can be conveniently applied in manipulation devices like the humanoid robot hand developed at the University of Bologna. The results of this application encourage a systematic investigation on the properties of this kind of joints, not previously described in the literature, aiming at mechanical characterization and definition of design criteria. To this purpose, the paper outlines a general investigation programme, where theoretical models, Finite Elements analysis and experiments jointly contribute to the evaluation of the hinge stiffness and to the identification of influential design parameters. Preliminary results related to evaluation of the stiffness about the principal bending axis are then examined and discussed, comparing the results obtained from experiments with those achieved by means of a simplified mathematical model and the correspondent FE analysis. An auxiliary parameter is finally introduced in order to define a general criterion for the design of spring-based hinges subjected to large deflection
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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