1,721,426 research outputs found

    Reduced order modelling of the non-linear stiffness in MEMS resonators

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    We propose a simplified numerical technique to quantify the effects of non-linear stiffness in MEMS resonators and we validate our approach on a clamped-clamped beam, a softening Disk Ring Gyroscope (DRG) and a shallow arch showing internal resonance. We generate a Reduced Order Model (ROM) which is integrated with either a direct integration approach or a continuation technique with arc length control. Finally we compare and validate the results with a full FEM model

    3d fluid–structure interaction simulation with an Arbitrary–Lagrangian–Eulerian approach with applications to flying objects

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    Air-structure interaction is a key aspect to account for during the design of Micro Air Vehicles. In this context, modelisation and numerical simulations represent a powerful tool to analyse aerodynamic performances. This work proposes an advanced fluid-structure interaction numerical technique for the simulation of dragonfly wings, considered one of the most interesting model due to their complex flapping kinematic. The fluid subproblem, described by incompressible Navier-Stokes equations, is solved in a Finite Element Arbitrary-Lagrangian-Eulerian framework, while the solid subproblem is addressed using structural Finite Element, such as membranes and beams. Moreover, a novel remeshing algorithm based on connectivity manipulation and refinement procedure has been implemented to reduce element distortion in fluid mesh, thus increasing the accuracy of the fluid solution. Firstly, the deformation of a single hindwing has been studied. Secondly, the dragonfly model is enriched by incorporating the forewing and a simplified thorax geometry. Preliminary results highlight the complex dynamic of the fluid around the body as well as the efficiency of the proposed mesh generation algorithm

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

    Preface

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