1,720,958 research outputs found
A Kalman-based identification approach for distributed aerodynamic loads on a rotating blade
No full textThe rotating blades of the helicopter are constantly interacting with the external fluid generating vibratory loads. These excitations are then transmitted to the rotor hub and can lead to failures in the main rotor system. The knowledge or prediction of the aerodynamic loads become thus of great importance for design and failure prevention. Several experiment-based and model-based techniques have been presented in literature, but given the complexity in helicopter modelling, high accuracy can only be reached if a large amount of sensor data and/or a high-fidelity numerical model is available. This contribution focuses on the usage of the Kalman filtering technique for rotor load estimation. The filter presents two main advantages: i) usage of a minimum set of sensors; ii) compensation of a low-fidelity model by accounting for sensor and model uncertainties. The problem of state and load estimation is addressed in this paper on a rotating helicopter blade through a numerical example. Numerical results show an accurate state reconstruction with respect to the selected sensor layout and model uncertainties. The distributed aerodynamic loads can be accurately reconstructed in post-processing
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
Blade Load Reconstruction from Embedded Strain Measurements
No full textRotorcraft blades are subject to significant dynamic loads both in standard and critical operating conditions. The knowledge and the prediction of the produced aerodynamic loads could represent an advantage in preventing failures on the rotorcraft, but also to avoid unnecessary inspections and reduce the downtime of the aircraft. This work applies the Kálmán filtering technique to estimate the aerodynamic loads on a helicopter rotor blade at wind-tunnel model scale, representative of that of a medium-weight helicopter (900 mm span and 72.5 mm chord, corresponding to a 1:5-1:8 model scale). The loads estimation is based on strain measurements provided by Fibre Bragg Grating sensors embedded in the blade at several spanwise sections. Two different test campaigns have been done: a static one to characterize the experimental set-up followed by a wind-tunnel test campaign. The results show that the Fiber Bragg Grating sensors could represent an alternative choice with respect to strain gauges for strain measurements in in-flight health monitoring
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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