Search results for "Mesh"

Functional a posteriori error estimates for boundary element methods

2019

Functional error estimates are well-established tools for a posteriori error estimation and related adaptive mesh-refinement for the finite element method (FEM). The present work proposes a first functional error estimate for the boundary element method (BEM). One key feature is that the derived error estimates are independent of the BEM discretization and provide guaranteed lower and upper bounds for the unknown error. In particular, our analysis covers Galerkin BEM and the collocation method, what makes the approach of particular interest for scientific computations and engineering applications. Numerical experiments for the Laplace problem confirm the theoretical results.

Systematic implementation of higher order Whitney forms in methods based on discrete exterior calculus

2022

AbstractWe present a systematic way to implement higher order Whitney forms in numerical methods based on discrete exterior calculus. Given a simplicial mesh, we first refine the mesh into smaller simplices which can be used to define higher order Whitney forms. Cochains on this refined mesh can then be interpolated using higher order Whitney forms. Hence, when the refined mesh is used with methods based on discrete exterior calculus, the solution can be expressed as a higher order Whitney form. We present algorithms for the three required steps: refining the mesh, solving the coefficients of the interpolant, and evaluating the interpolant at a given point. With our algorithms, the order of…

On a numerical solution of the Maxwell equations by discrete exterior calculus

2014

Polygonal mesh segmentation by surface curvature diffusion.

2011

First World War Diaries: Making the Private Public

2020

This article analyses several World War I Diaries written by soldiers on the Front. Starting with the circumstances of publication and their effects on the text, the article addresses the passage of these very private texts into public life, before turning to the role played by the diaries for the soldiers who write them. Studies of the diary as a genre are used to show how war diaries fit into the more general genre. Finally the article turns to the reception of these works, by studying what part literary distance may play for the soldiers keeping a diary, and by arguing that the task of making sense of these texts has been transferred to present-day readers.

Inserimento di restringimenti e ponti in un modello diffusivo 2D di acque basse

2010

Gli effetti su una corrente, causati dalle pile di un ponte, o più in generale da strutture che riducono la sezione trasversale dell’alveo, risultano di particolare interesse per le variazioni idrometriche che comportano alla corrente stessa. Nonostante i numerosi studi teorici e sperimentali di letteratura, l’attuale modellistica numerica diffusiva non integra la presenza di tali manufatti nelle proprie tecniche risolutive. Nella presente memoria viene presentata la metodologia implementata nel modello diffusivo bidimensionale FLOW2D per la valutazione del rigurgito provocato da restringimenti della sezione trasversale, nonché dalla presenza delle campate. I profili di rigurgito ottenuti c…

L'approche cartographique de la représentation du mouvement spatial. L'exemple des flux commerciaux maritimes euro- méditerranéens

2016

Mapping spatial movement implies to rethink cartographic modelling in addition to digital data issues. This opens research pathways about the representation of spatio-temporal interactions and interrelations. Existing approaches focus either on the map background itself (data analysis issues, to answer thematic questions) or on its “shape”, i.e. on the pure graphical aspects of visualization (edge bundling) and on the semiology rules behind it. This paper aims to further examine the role of the map background in the cartography of maritime flows. This essentially geographic approach differs from existing ones in that it approximates the representation of movement by modelling the mesh of th…

Study and Simulation of Helicopter Gearboxes Noise

2010

International audience; Main gearbox is one of the main noise sources in helicopter cabin. In order to improve the comfort of customers and reduce the health impact, acoustic and vibration mechanisms of gearboxes have to be understood and simulated during development phases. Thus, we first present the global methodology chosen to compute main gearboxes noise in helicopter cabins. Secondly, we described the way we compute mechanical excitation sources induced from gear mesh, static transmission error and meshing stiffness. Depending on the type of gear, we compute those using either analytical specially developed code or EC codes. Thirdly, we propose a modeling to compute dynamic loads on be…

TP53 mutations and S-phase fraction but not DNA-ploidy are independent prognostic indicators in laryngeal squamous cell carcinoma

2005

To prospectively evaluate the prognostic significance of TP53, H-, K-, and N-Ras mutations, DNA-ploidy and S-phase fraction (SPF) in patients affected by locally advanced laryngeal squamous cell carcinoma (LSCC). Eight-one patients (median follow-up was 71 months) who underwent resective surgery for primary operable locally advanced LSCC were analyzed. Tumor DNA was screened for mutational analysis by PCR/SSCP and sequencing. DNA-ploidy and SPF were performed by flow cytometric analyses. Thirty-six patients (44%) had, at least, a mutation in the TP53 gene. Of them, 22% (8/36) had double mutations and 3% (1/36) had triple mutations. In total, 46 TP53 mutations were observed. The majority (41…

Optical quality of hyperopic and myopic phakic intraocular lenses

2013

Aims: To assess and compare the optical quality of the myopic and hyperopic implantable collamer lens (ICL) from its wavefront aberrations for different powers and pupil diameters. Settings and Design: Prospective study. Material and Methods: The wavefront aberrations of two myopic (−3 and −6 diopters (D)) and two hyperopic V4b ICLs (+3 and +6D) were measured in vitro . To assess and compare the optical quality of different powers of ICLs, we analyzed the root mean square (RMS) of total higher order aberrations (HOAs), trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration at 3- and 4.5-mm pupil. In addition, the point spread functions (PSFs) of each ICL evaluated were ca…