Search results for "DtN"
showing 5 items of 5 documents
Network Connectivity and Area Coverage for UAV Fleet Mobility Model with Energy Constraint
2016
International audience; Our main focus through the present paper is on developing an original distributed mobility model for autonomous fleet of interconnected UAVs (Unmanned Aerial Vehicles) performing an area exploration mission. The UAVs, equipped with wireless ad-hoc capabilities, are required to optimally explore an area while maintaining connectivity with their neighboring UAVs and the base station. Because energy is a scarce resource, especially for UAVs, its wise management is quite beneficial for the network lifetime and mission success. Hence, the proposed mobility model, compared to other models in the literature, is the first to ever include the remaining energy level as decisio…
Modeling by the finite element method of acoustic radiation in waveguides lined with locally or non locally reacting absorbent materials in the prese…
2011
Our concern in this work is the problem of acoustic propagation in guides lined with locally or non locally reacting materials with the presence of mean fluid flow. In several industrial systems such as aircraft jet engines, mufflers exhaust and ventilation systems, noise is mostly channeled outside by guides of more or less complex geometries. A study of waveguides makes it possible to predict and understand the physical phenomena such as refraction, convection, absorption and wave attenuation. In waveguides studies, guides are often considered infinitely long to get rid of some phenomena (reflection for example) at their ends. Solving the problem of acoustic propagation in infinite guides…
Transparent boundary condition for acoustic propagation in duct with bulk-reacting liner
2012
International audience; The proposed study focuses on the modeling of acoustic wave propagation in infinite guides lined with bulk-reacting sound absorbing material which allows acoustic propagation through the lining. The finite element method is used, it is then necessary to limit the numerical domain by an artificial boundary on which a transparent boundary condition is introduced. The method described in this work consist to write the transparent condition as a Dirichlet to Neumann operator (DTN) based on a modal decomposition of the pressure in the guide. This study is a generalization of recent works with absorbent materials modeled with impedances boundary condition. The presented me…
Opérateur DtN pour les guides cylindriques à paroi traitée en présence d'un écoulement uniforme
2010
National audience; On s'intéresse au problème de rayonnement acoustique d'une source dans une conduite cylindrique axisymétrique infinie dont la paroi est recouverte d'un matériau absorbant en présence d'un écoulement uniforme. Dans le but d'utiliser la méthode des éléments finis, le domaine infini doit être tronqué par une frontière artificielle sur laquelle une condition limite transparente est introduite. La méthode exposée dans ce travail consiste à écrire la condition transparente sous la forme d'un opérateur Dirichlet to Neumann (DtN) obtenu par la généralisation de travaux réalisés dans le cas d'un guide 2D infini. Cet opérateur est basé sur une décomposition modale qu'il est facile …
Muscle adenylate kinase in Duchenne muscular dystrophy
1986
Abstract On the basis of electrophoretic and enzyme inhibition studies it was postulated that an aberrant adenylate kinase occurs in muscle and serum of patients with Duchenne muscular dystrophy (Schirmer, R.H. and Thuma, E. (1972) Biochim. Biophys. Acta 268, 92–97; Hamada, M. et al. (1981) Biochim. Biophys. Acta 660, 227–237; Hamada et al. (1985) J. Biol. Chem. 260, 11595–11602. On the basis of the following results we conclude that Duchenne muscular dystrophy patients do not possess an unusual adenylate kinase isoenzyme. (1) In muscle biopsies from five Duchenne patients, the electrophoretic mobility of adenylate kinase and the inhibition of the enzyme by P 1 , P 5 -di(adenosine-5′)pentap…