1,721,020 research outputs found
Il BEM per il problema di Dirichlet su un dominio esterno ad un arco relativo all'equazione di Helmholtz
No full textWave propagation analysis with boundary element method
Full text linkTime-dependent problems, that are frequently modelled by hyperbolic partial differential equations, can be dealt with the boundary integral equations (BIEs) method. The ideal situation is when the partial differential equation is homogeneous with constant coefficients, the initial conditions vanish and the data are given only on the boundary of a domain independent of time. In this situation the transformation of the differential problem to a BIE follows the same well-known method for elliptic boundary value problems. In fact the starting point for a BIE method is the representation of the differential problem solution in terms of single layer and double layer potentials using the fundamental solution of the hyperbolic partial differential operator
Wave propagation analysis with boundary element method
No full textTime-dependent problems, that are frequently modelled by hyperbolic partial differential equations, can be dealt with the boundary integral equations (BIEs) method. The ideal situation is when the partial differential equation is homogeneous with constant coefficients, the initial conditions vanish and the data are given only on the boundary of a domain independent of time. In this situation the transformation of the differential problem to a BIE follows the same well-known method for elliptic boundary value problems. In fact the starting point for a BIE method is the representation of the differential problem solution in terms of single layer and double layer potentials using the fundamental solution of the hyperbolic partial differential operator.
(Pubblicata - vedi http://hdl.handle.net/2434/148419
PROCEEDINGS OF SIMAI 2020+21: THE XV BIANNUAL CONGRESS OF SIMAI 30 August - 3 September 2021 Parma, Italy
No full textThe book collects the abstracts of the bi-annual congress of the Italian Society of Applied and Industrial Mathematics (SIMAI) held from August 30 to September 3, 2021 at the University of Parma. The Congress met together about 500 researchers from academia and industry active in the study of mathematical and numerical models as well as in their applications to industrial and real life problems. The aim of this traditional event is to stimulate interdisciplinary research in Applied Mathematics and to foster interactions of the scientific community with industry. The content of this book is made by the contributions of: 6 Plenary Speakers; 63 Minisymposia and some other individual contributions; the "Industrial Session", a special event gathering together academic and industrial representatives to work on mathematical problems encountered in Research & Development areas; "EDU-SIMAI session", the event dedicated to the relationship with Secondary Schools on the subject of applied mathematics teaching
A 2D space-time BEM for exterior problems
No full textHere we consider Dirichlet or Neumann wave propagation for 2D exterior problems reformulated in terms of boundary integral equations with retarded potential. Starting from a natural energy identity, a space-time weak formulation
for the boundary integral equations is proposed and discussed. Numerical evidences of the effectiveness of our approach, as well as some applications, are
presented
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
A space-time energetic formulation for wave propagation analysis by BEMs
No full textIn this paper we consider one-dimensional wave propagation problems, with suitable boundary conditions, reformulated using space-time boundary integral equations with retarded potential. In the first part, special attention is devoted to a formulation based on a natural energy identity that leads to a space-time weak formulation of the corresponding boundary integral equations with robust theoretical properties. Continuity and coerciveness of the bilinear form related to the energetic formulation are proved. Then we compare the new energetic weak formulation with different other time-domain boundary element method procedures applied to wave propagation analysis in layered media. The paper concludes with several numerical tests to demonstrate the effectiveness of the introduced technique in the numerical solution of Dirichlet-Neumann problems in their integral formulation, pointing out the numerical properties of the derived linear systems
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
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