1,720,968 research outputs found
Piezoelectric Energy Harvesting for Autonomous Sensors in Structural Health Monitoring of Bearings and Ballscrews
No full textComparison of PM Brushless motors for helicopter tail rotor Fenestron type
No full textThis paper presents the design of spoke-type permanent magnet motor for an electrical tail rotor. The electrical machine is designed for air cooling and a high TRV is requested. The design should guarantee a high reliability due to the safety critical system definition for a tail rotor and should match a given envelope to allow a substitution of the actual mechanisms. In order to obtain high torque maintaining small overall dimensions of the motor, a spoke-type solution with interior PMs has been chosen and compared with a V-shape type arrangement of the magnets. The motor performance have been evaluate by the FE analysis in the healthy and faulty mode operations: the performance fully satisfy the requirements at low and high power. The study has been completed with a detailed thermal analysis in order to calculate the temperature in the stator winding and PMs at steady-state imposing the severe duty cycle
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
Robot Choreographies: Artificial Evolution between Novelty and Similarity
Full text linkIn this paper we introduce a novel fitness function for evolutionary art, which generates sequences of movements--i.e. robot choreographies--based on similarity to an inspiring repertoire. Similarityis counterbalanced by a novelty mechanisms, which makes it possible to sample unexplored areas ofthe choreography space. The approach is discussed together with preliminary results achieved in thecontext of Nō theatre. This work is a first step towards the development of a computational creativitysystem that can incorporate diverse generative mechanisms and can exploit information theoretic andcomplexity measures both for the generation and assessment of the choreographies produce
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
Electric powertrain for helicopter tail rotor
No full textThe design of multi-phase permanent magnet brushless motor for an electrical helicopter tail rotor is introduced and described. The presented electric machine allows a substitution of the actual mechanisms in tail rotor system matching envelope, weights and performances. In order to obtain high torque with small overall dimensions of the motor, a spoke-type solution with interior PMs has been chosen. An optimization procedure has been used to combine thermal and electromagnetic requirements with the aim to improve the overall design. The motor performance has been evaluated by the FE analysis to validate the final design and start the prototype production
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