1,720,980 research outputs found
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
Residual Generator Design and Performance Evaluation for Aircraft Simulated Model FDI
No full textIn this work, a model–based procedure exploiting
analytical redundancy for the FDI of faults on a multivariable
dynamic process is presented. The main point of the paper
consists of exploiting a disturbance decoupling scheme in
connection with a dynamic filter design procedure for diagnostic
purpose. It is shown that the suggested approach to fault
diagnosis is in particular advantageous in terms of solution
complexity and performance. Moreover, the presented method
is especially useful when robust solutions are considered for
minimising the effects of modelling errors and noise, while maximising fault sensitivity. In order to verify the robustness of the
solution achieved, the proposed design has been experimented
with the data of a simulated aircraft model in the presence
of both measurement and modelling errors. Finally, extensive
simulations of the test–bed process and Monte Carlo analysis
are the tools used for assessing the overall capabilities of the
developed FDI scheme, when compared also with different
data–driven diagnosis methods
Nonlinear Actuator Fault Detection and Isolation for a General Aviation Aircraft
No full textThis paper addresses the problem of detection and isolation of actuator faults for a general aviation aircraft, where the nonlinear simulation aircraft model embeds the effects of wind gusts, atmospheric turbulence and measurement errors. The approach is based on the recently introduced NonLinear Geometric Approach
(NLGA) to the Fault Detection and Isolation (FDI) problem. The actuators FDI is performed in a coordinated turn, hence with coupled longitudinal and lateral–directional dynamics. This work represents the first complete NLGA FDI scheme for a general aviation aircraft in a condition with tight–coupled dynamics. The
results obtained in the simulation of the faulty behaviour of a nonlinear Piper PA30 aircraft are finally reporte
Design and Performance Analysis of Residual Generators for the FDI of Aircraft Model Sensors
No full textIn this work, a model–based procedure exploiting analytical redundancy for the detection and isolation of faults on a multivariable linear dynamic process is presented. The main point of the paper consists of exploiting a disturbance decoupling
scheme in connection with dynamic filter design procedure for diagnostic purpose. It is shown that the suggested approach to fault diagnosis is in particular advantageous in terms of solution complexity and performance. Moreover, the presented method is especially useful when robust solutions are considered for
minimising the effects of modelling errors and noise, while maximising fault sensitivity. In order to verify the robustness of the solution achieved, the proposed design has been experimented with the data of a simulated aircraft model in the presence of both measurement and modelling errors. Finally, extensive simulations
of the test–bed process and Monte Carlo analysis are the tools used for assessing the overall capabilities of the developed FDI scheme, when compared also with different data–driven diagnosis methods
Fault Diagnosis Strategies for a Simulated Nonlinear Aircraft Model
No full textIn this work, different procedures for sensor Fault Detection and Isolation (FDI)
applied to a simulated model of a commercial aircraft are presented. The main point of the
paper regards the design of two FDI schemes based on a linear Polynomial Method (PM) and
the NonLinear Geometric Approach (NLGA). The obtained results highlight a good trade–off
between solution complexity and achieved performances. The FDI schemes are applied to the
aircraft model, characterised by tight–coupled longitudinal and lateral dynamics. The properties
of the residual generators are experimentally investigated and verified by simulating a general
aircraft reference trajectory. The overall performance of the developed FDI schemes are analysed
in the presence of turbulence, measurement and model errors. Comparisons with other FDI
methods based on Neural Networks (NN) and Unknown Input Kalman Filter (UIKF) are finally
reported
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
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