1,720,982 research outputs found
An algorithm for the fast estimate of the Maximum Power voltages in PV applications adopting microconverters
No full textOptimitation of Distributed Maximum Power Point tracking PV applications: the Scan of the Power vs Voltage input characteristic of the inverter
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A new strategy for the identification of optimal operating points in PV applications with Distributed MPPT
No full textIn this paper, a new control strategy
allowing to optimize the performances of PV systems
adopting Distributed Maximum Power Point Tracking (DMPPT), is presented and discussed. It is based on the
estimate of the optimal operating range of the inverter
input voltage and of the optimal operating voltages of the
PV modules. The main advantage of the proposed
technique is represented by the fast identification of a set
of operating points for the inverter and for the PV
modules, which allows to obtain a marked increase of the
speed of tracking both of the inverter and of the DC/DC
converters performing the DMPPT function. Moreover, a
further advantage is represented by the possibility to
avoid that, due to mistakes of the inverter MPPT
technique, the operating value of the inverter input
voltage remains trapped in the neighborhood of a
suboptimal operating point
A Hybrid MPPT technique based on the Fast Estimate of the Maximum Power Voltages in PV applications
No full textln PV applications, under mismatching
conditions, the adoption of a Maximum Power Point Tracking
(MPPT) technique which is able to regulate not only the
voltages of the PV modules of the array, but also the DC input
voltage of the inverter is necessary in order to inject into the
grid the maximum available energy. Such a technique can be
considered an Hybrid MPPT (HMPPT) technique wh ich is
neither only distributed on the PV modules of the PV array or
only centralized at the input of the inverter. In this paper a
new HMPPT technique is presented and discussed. Its main
advantages are the high MPPT efficiency and the high speed of
tracking obtained by means of a fast estimate of the maximum
power voltages ofthe PV modules and ofthe inverter. The new
HMPPT technique is compared with a HMPPT technique
based on the coupled adoption of the Perturb & Observe
technique, distributed on the PV modules, and of a suitable
centralized MPPT technique carried out by the controller of
the central inverter and based on the periodic scan of the
power versus voltage characteristic at the input ofthe inverter
An algorithm for the Estimation of the Maximum Power Voltages in microconverters based PV applications
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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
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