1,721,160 research outputs found
Nuovi strumenti per un’antica speranza: Nuove tecnologie per la partecipazione democratica. Prolegomeni per un uso non tecnocratico delle tecnologie
No full textNew tools for an old hope: New Technologies and the democratic participation. Prolegomena for a non-technocratic use of Technologies
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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
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
Phase shifter based on DDS-driven offset-PLL
No full textA new topology for phase-shift control in the transmitter module of phased array antennas is introduced. The proposed structure is based on a hybrid DDS-PLL approach. An offset-PLL evolution is proposed in order to preserve phase resolution, along with a maximum phase shift of 360deg. Experimental results obtained by a prototype are reported, validating the architecture potentialitie
Effect of the unbalanced magnetic pull in two-poles slim generators: modelling and experimental validation
No full textThe paper presents the modelling of the unbalanced magnetic pull (UMP) and its experimental validation in a
real machine. It is well known that in electrical machines rotor eccentricity causes an imbalance of the
electromagnetic forces acting upon rotor and stator surfaces, so that a net radial force is developed. Large
generators of power plants operate above their first critical speed behaving like flexible shafts, therefore the
eccentricity of the active part of the rotor with respect to the stator is unavoidable.
In the first part of the paper, an original model that calculate the UMP force is presented. This model is based on the actual position of the rotor inside the stator, therefore on the air gap distribution, independently of the orbit type. The closed form of the non-linear UMP force components is expressed.
In the second part, the experimental validation is presented, by considering a steam turbo-generator of a power plant and by comparing the simulated dynamic behaviour in the time domain of the machine without and with the excitation of the magnetic field in the generator
On the effects of a shaft crack propagation on the dynamic behavior of a steam turbine
No full textThe symptoms of the propagation of shaft cracks in rotating machines, which can be brought out of the vibration data collected by condition monitoring systems, are often not very evident, especially when the crack depth is not very high. In fact, shaft cracks commonly propagate rather far from the cross-sections where the vibration probes have been mounted. At these measurement planes, the sensitivity of the machine dynamic behavior to the effects caused by a shaft crack can be fairly low. Therefore, it is very important to improve the capabilities of diagnostic techniques aimed at the early detection of shaft cracks. In this paper, the dynamic behavior of the cracked shaft of a HP-IP steam turbine is shown. The results of investigations on the influence of the periodic and non-periodic breathing of the crack on the rotor response, measured in different machine thermal states and at unusual cross-sections of the shaft, are shown and discussed
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