1,720,960 research outputs found
Identification of the smart spring properties from FRFs measurements
No full textThe objective of this paper is the dynamic identification of a reduced-scale helicopter
blade system that incorporates an active pitch link or smart spring for vibration control.
The identification of the Smart Spring parameters, in terms of the masses and stiffnesses
associated to its components, is carried out in the frequency domain using a developed
sensitivity-based updating method. This method, called Predictor-Corrector, iteratively
minimizes a residual vector of correlation functions, defined on the Frequency Response
Functions (FRFs), in order to obtain the unknown values of the parameters that well rep-
resent the dynamic behavior of the smart spring. In the paper the accuracy of the solution
provided by the developed technique is assessed through several numerical analyses. For
this purpose, a lumped parameter numerical model of the Smart Spring was developed
and the effects of various mass and stiffness distribution scenarios on the modal properties
of the system are presented. Due to the nonlinear dynamic behavior of the smart spring
system, a linear approximation of the system around a prescribed operative working con-
dition is considered. Finally, the developed approach is applied for the identification of the
dynamic parameters of a real smart spring system. It is shown that acceptable values of
the equivalent lumped parameters were achieved also considering experimental data such
as those recorded during a test campaign carried out at the Smart Rotor Laboratory of
the Carleton University, thus validating the identification approach
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
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
Identification of the Dynamic Properties of Active Twist Rotor Model Blade Using Output-Only Data
No full textn this paper, an approach to estimate the dynamic characteristics of a rotating
blade using response data is proposed. A test campaign devoted to demonstrate the capability
of the Smart Spring device to alter the dynamic properties of the rotating blade is carried out in
the framework of the Smart Hybrid Active Rotor Control System, SHARCS, project. Within this
project, the key factor is an active vibration control concept that uses piezoceramic actuators to
preferentially vary dry friction and stiffness of a structure. This device, if located at the blade
root, could adaptively vary the dynamic stiffness of the blade to change its flexural characteristics,
thus allowing control of the aeroelastic response of the entire blade. In this paper it is shown how
the modal parameters will be estimated from the time histories recorded, by a distributed array
of sensors, at different rotational speed of the blade and for different values of the stiffness of the
Smart Spring device. Both time domain and frequency domain methods were applied in order
to quantify the effects on the modal properties of different operating conditions of a prototype
version of the Smart Spring device. This device was attached to the push rod of an Active Twist
Rotor blade developed at the German Aerospace Center (DLR). From the performed experimental
investigation, carried out at the DLR’s whirl tower test facility, it was possible first to draw the
typical fan plots of the rotating blade, from which useful information about the dynamic behavior
of the system could be achieved. Then, a validation of the numerical model of the smart spring
device was obtained
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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