1,720,980 research outputs found
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
Identification de robots industriels rigides – Apport des méthodes de l’identification de systèmes
No full textL’industrie moderne fait largement appel à des robots industriels afin de réduire les coûts, ou encore améliorer la productivité et la qualité par exemple. Pour ce faire, une haute précision et une grande vitesse sont simultanément nécessaires. La conception de lois de commande conformes à de telles exigences demande une modélisation mathématique précise de ces robots. A cette fin, des modèles dynamiques sont construits à partir de données expérimentales. L’objectif de cette thèse est ainsi de fournir aux ingénieurs roboticiens des outils automatiques pour l’identification de bras robotiques. Dans cette perspective, une analyse comparative des méthodes existantes pour l’identification de robot est réalisée. Les avantages et inconvénients de chaque méthode sont ainsi mis en exergue. À partir de ces observations, les contributions sont articulées selon trois axes. Premièrement, l’étude porte sur l’estimation des vitesses et accélérations des corps du robot à partir de la position mesurée. Ces informations sont en effet nécessaires à la construction du modèle. La méthode usuelle est basée sur prétraitement "sur mesure" qui requière une connaissance fiable des bande-passantes du système, alors que celui-ci est encore inconnu. Pour surmonter ce dilemme, nous proposons une méthode capable d’estimer les dérivées automatiquement sans réglage préalable par l’utilisateur. Le deuxième axe concerne l’identification du contrôleur. Sa connaissance est en effet requise par la grande majorité des méthodes d’identification. Malheureusement, pour des raisons de propriété industrielle, il n’est pas toujours accessible. Pour traiter ce problème, deux méthodes sont introduites. Leur principe de base est d’identifier la loi de commande dans un premier temps avant d’identifier le modèle dynamique du bras robotique dans un second temps. La première méthode consiste à identifier la loi de commande de manière paramétrique, alors que la seconde fait appel à une identification non-paramétrique. Finalement, le troisième axe porte sur le réglage "sur mesure" du filtre decimate. L’identification du filtre de bruit est introduite en s’inspirant des méthodes développées par la communauté d’identification de systèmes. Ceci permet l’estimation automatique des paramètres dynamiques avec de faibles covariances tout en apportant une connaissance concernant la circulation du bruit à travers le système en boucle-fermée. Toutes les méthodes proposées sont validées sur un robot industriel à six degrés de liberté. Des perspectives sont esquissées pour de futurs travaux portant sur l’identification de systèmes robotiques, voire d’autres applications.In modern manufacturing, industrial robots are essential components that allow saving cost, increase quality and productivity for instance. To achieve such goals, high accuracy and speed are simultaneously required. The design of control laws compliant with such requirements demands high-fidelity mathematical models of those robots. For this purpose, dynamic models are built from experimental data. The main objective of this thesis is thus to provide robotic engineers with automatic tools for identifying dynamic models of industrial robot arms. To achieve this aim, a comparative analysis of the existing methods dealing with robot identification is made. That allows discerning the advantages and the limitations of each method. From those observations, contributions are presented on three axes. First, the study focuses on the estimation of the joint velocities and accelerations from the measured position, which is required for the model construction. The usual method is based on a home-made prefiltering process that needs a reliable knowledge of the system’s bandwidths, whereas the system is still unknown. To overcome this dilemma, we propose a method able to estimate the joint derivatives automatically, without any setting from the user. The second axis is dedicated to the identification of the controller. For the vast majority of the method its knowledge is indeed required. Unfortunately, for copyright reasons, that is not always available to the user. To deal with this issue, two methods are suggested. Their basic philosophy is to identify the control law in a first step before identifying the dynamic model of the robot in a second one. The first method consists in identifying the control law in a parametric way, whereas the second one relies on a non-parametric identification. Finally, the third axis deals with the home-made setting of the decimate filter. The identification of the noise filter is introduced similarly to methods developed in the system identification community. This allows estimating automatically the dynamic parameters with low covariance and it brings some information about the noise circulation through the closed-loop system. All the proposed methodologies are validated on an industrial robot with 6 degrees of freedom. Perspectives are outlined for future developments on robotic systems identification and other complex problems
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Comparison of Numerical Differentiation Techniques for Aircraft Identification
No full textInternational audienceExternal disturbance and measurement noise during flight tests inevitably degrade the identification of the aircraft aerodynamic models. Traditional approaches, however, need to differentiate the measured signals to build the identification models, which results in a dedicated preprocessing to avoid noise amplification. The aim of this paper is to assess the influence of four derivative estimation techniques on the parameter estimation of an aircraft aerodynamic model. Among the four studied techniques, two come from the field of robot identification. The other two techniques are the standard one in aircraft identification based on the Savitzky-Golay algorithm and a suggested one based on wavelet denoising coupled with finite differences. The two techniques coming from robot identification are the usual one relying on a low-pass filter applied in both forward and backward directions and a recently suggested method based on a Kalman filter with a first-order random walk model. The comparison simulation results illustrate that the first robot differentiation strategy not only performs well in providing accurate stability and control derivatives even in the presence of colored disturbance but also is competitive with respect to the standard method in aircraft identification
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