1,721,007 research outputs found
An intelligent off-line MPPT technique for PV applications
No full textHarnessing energy from the abundant and free sunlight is now a days a hot topic among the research community. The availability of cheap solar modules has made it possible to harvest solar energy with better efficiency. The nature of solar modules is non linear and therefore the process of impedance matching is essential. The proper impedance matching ensures extraction of the maximum power from solar PV module. Several algorithms are reported in literature that are used to operate the DC-DC converter around Maximum Power Point (MPP). Among those algorithms off-line techniques are considered the easiest to implement. However, intermittent measurement of Short Circuit Current (SCC)/Open Circuit Voltage (OCV) results in the power loss. The decision about the measurement of SCC/OCV is often based on the irradiance/temperature sensors. In this paper we propose a modified algorithm for off-line MPPT techniques. The proposed technique decides intelligently about the measurement of SCC/OCV. The technique is modeled and simulated in Matlab/Simulink and the results shows satisfactory performance against test conditions
A Single Sensor-Based Detection Mechanism for L-L/L-G Faults of PV Array
No full textIn this article, a single sensor-based fault detection mechanism (FDM) is proposed to detect the line-to-line (L-L) and line-to-ground (L-G) faults in a photovoltaic (PV) array. The hardware framework contains an extra dc-bus and capacitor-diode pair for each string and a single current sensor. Compared with the past hardware topologies, the proposed FDM delivers the following critical advantages: 1) fault is detected at string level along with its type in milliseconds time frame, which ensures that there is no fire-hazard in PV plant; 2) string under fault automatically disconnects from other healthy strings through passive RC network; and 3) the installation of co-hardware-software system is low cost with negligible active-power field circuits and operates with a simple algorithm. The scientific philosophy and comprehensive analysis of the proposed FDM are provided. To evaluate the effectiveness of the proposed FDM, computer simulations and practical experiments are performed on numerous fault scenarios in a PV array. These results not only validate the fundamental operation of the proposed FDM along with its features but also highlight its excellent accuracy in detecting faults
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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