1,720,957 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
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
Numerische Nichtlineare Algebra
No full textNumerical nonlinear algebra is concerned with the development of numerical methods to solve problems in nonlinear algebra. The main computational task is the solution of systems of polynomial equations. In this thesis, we focus on the numerical solution of polynomial systems using homotopy continuation methods. We apply techniques from numerical analysis to obtain a mixed-precision path tracking algorithm specifically designed for the application in polynomial homotopy continuation methods. This algorithm uses an adaptive step size control that builds on a local understanding of the region of convergence of Newton's method and the distance to the closest singularity.
Important for the use of numerical nonlinear algebra in mathematical proofs is the possibility to certify that the computed approximate solutions of a polynomial system correspond to true (distinct) solutions of the system. We present a new certification routine based on interval arithmetic and Krawczyk's method that outperforms the state of the art by multiple orders of magnitude. We also demonstrate numerical nonlinear on a range of applications. To illustrate tools and techniques from numerical nonlinear algebra, we consider Steiner's conic problem and give the first fully real instance of Steiner's conic problem using a computer-assisted proof. We study the action of the projective linear group on cubic surfaces.
In particular, we compute the degree of the projective variety given by the Zariski closure of the orbit of a general cubic surface. We also consider the maximum likelihood estimation problem for Gaussian models whose covariance matrices lie in a given linear space. Using numerical nonlinear algebra, we compute the ML degree and dual ML degree for various models of linear covariance matrices. Another application is the study from tensegrity frameworks made from rigid bars and elastic cables, depending on many parameters. We use numerical nonlinear algebra to sample the semi-algebraic catastrophe set which characterizes a region of the parameter space that can trigger sudden large-scale shape changes.
Finally, we present the software package HomotopyContinuation.jl for the numerical solution of polynomial systems. We describe its functionality, share some of its design and implementation details and demonstrate its impact on the broader research community.Numerische nichtlineare Algebra beschäftigt sich mit der Entwicklung von numerischen Methoden zur Lösung von Problemen in der nichtlinearen Algebra. In der nichtlinearen Algebra ist die zentrale Berechnungsaufgabe das Lösen von System von polynomiellen Gleichungen ist. In dieser Dissertation fokussieren wir uns auf das Lösen von Polynomsystem mittels Homotopie-Fortsetzungsverfahren. Wir wenden Techniken aus der numerischen Analysis an, um einen gemischte Präzision Pfadverfolgungsalgorithmus zu erhalten, der speziell für die Anforderungen von polynomiellen Homotopie-Fortsetzungsverfahren gestaltet ist. Dieser Algorithmus nutzt eine adaptive Schrittweitensteuerung, welche auf einem lokalen Verständnis der Konvergenzregion vom Newtonverfahren und dem Abstand zur nächsten Singularität basiert.
Wichtig für die Anwendung von Methoden der numerischen nichtlinearen Algebra in mathematischen Beweisen ist die Möglichkeit zu zertifizieren, dass die berechneten approximativen Lösungen eines Polynomsystems zu echten (unterschiedlichen) Lösungen des Systems korrespondieren. Wir implementieren eine neue Zertifizierungsmethode basierend auf Intervallarithmetik und dem Krawczyk-Verfahren, welche den aktuellen Stand der Technik um mehrere Größenordnungen schlägt. Wir demonstrieren außerdem numerische nichtlineare Algebra an einer Reihe von Anwendung. Um die Werkzeuge und Techniken der numerischen nichtlinearen Algebra zu demonstrieren, betrachten wir Steiners Kegelschnittproblem und geben die erste komplett reelle Instanz mittels eines computergestützten Beweises an.
Wir betrachten die Wirkung der projektiven linearen Gruppe auf kubischen Flächen und berechnen den Grad der projektiven Varietät, die durch den Zariskiabschluss des Orbits einer allgemeinen kubischen Fläche gegeben ist. Wir betrachten zudem das Problem der Maximum-Likelihood Schätzung für Modelle von Gaußschen Verteilungen, dessen Kovarianzmatritzen innerhalb eines gegeben linearen Raums liegen. Mittels numerischer nichtlinearer Algebra berechnen wir den ML Grad und den dualen ML Grad für verschiedene Modelle von linearen Kovarianzmatritzen. Eine weitere Anwendung ist die Untersuchung von Tensegrity Frameworks, welche aus starren Stangen und elastischen Kabeln bestehen.
Wir benutzen numerische nichtlineare Algebra, um die semi-algebraische Katastrophenmenge zu samplen, welche die Region des Parameterraums charakterisiert, die plötzliche große Formveränderungen auslösen kann. Abschließend präsentieren wir das Softwarepaket HomotopyContinuation.jl für die numerische Lösung von Polynomsystemen. Wir beschreiben seine Funktionalität, teilen einige der Design- und Implementierungsdetails und demonstrieren seinen Einfluss auf die breitere Forschungsgemeinschaft
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Mixed precision path tracking for polynomial homotopy continuation
Full text linkThis article develops a new predictor-corrector algorithm for numerical path tracking in the context of polynomial homotopy continuation. In the corrector step, it uses a newly developed Newton corrector algorithm which rejects an initial guess if it is not an approximate zero. The algorithm also uses an adaptive step size control that builds on a local understanding of the region of convergence of Newton’s method and the distance to the closest singularity following Telen, Van Barel, and Verschelde. To handle numerically challenging situations, the algorithm uses mixed precision arithmetic. The efficiency and robustness are demonstrated in several numerical examples.DFG, 385256563, GRK 2434: Facetten der KomplexitätTU Berlin, Open-Access-Mittel – 202
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