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Conservative linear models for the vibrating string and rod free to slide, at one end point, on a vertical guide.
No full textAbstractThe motion of a linear vibrating string, or rod, fixed in one point and free to slide on a vertical guide in the other one, is studied. Only transversal vibrations are considered. The motion is simulated by a discrete conservative model. In order to prove that the total energy is conserved, a matrix form of the potential and kinetic energy is used. The same technique may be used to simplify the proof of energy conservation theorem given by the authors in a previous paper.The numerical method related to the model turns out to be unconditionally stable. Some examples of the motion simulated by the model are given
The vibrating string and rod free to slide, at both end points, on a vertical guide.
No full textAbstractSome algebraic properties of the matrices involved in a discrete linear model simulating the transversal motion of a linear vibrating string, or rod, with both end points free to slide on vertical guides, are studied. The discrete linear model, which is conservative, turns out to be, according to the physics of the problem, generally unstable. Nevertheless, it is proved that the linear models are suitable to simulate the motion of the linear string and rod. An extension of the model to the nonlinear string is also considered and some numerical examples are given. Also, in this case, the numerical results seem to be in accordance with the physics of the problem
Discrete conservative models for the simulation of the motion of a vibrating string or rod
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A discrete conservative model for the linear vibrating string and rod.
No full textAbstractIn this paper, we shall suggest and study a conservative discrete model for the linear vibrating string and rod fixed at the end points. We shall prove that the difference systems involved in our models may be seen as second-order unconditionally stable finite difference schemes of the classical equations of the linear vibrating string and vibrating rod. If the forces acting on the string (or rod) are conservative the total energy of the discrete solutions of our models is conserved and we can prove that we have stability for every choice of the time step Δt. We have considered both hinged and clamped rod; the constrains are naturally included into the model and the conservation of energy is still proved by giving a suitable definition of potential energy. Some numercial examples are presented
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
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