Displaying 421 – 440 of 543

Showing per page

Thermo-visco-elasticity with rate-independent plasticity in isotropic materials undergoing thermal expansion*

Sören Bartels, Tomáš Roubíček (2011)

ESAIM: Mathematical Modelling and Numerical Analysis

We consider a viscoelastic solid in Kelvin-Voigt rheology exhibiting also plasticity with hardening and coupled with heat-transfer through dissipative heat production by viscoplastic effects and through thermal expansion and corresponding adiabatic effects. Numerical discretization of the thermodynamically consistent model is proposed by implicit time discretization, suitable regularization, and finite elements in space. Fine a-priori estimates are derived, and convergence is proved by careful...

Three dimensional modelling of the peach in MAPLE

Bartoň, Stanislav (2008)

Programs and Algorithms of Numerical Mathematics

Linearized Gauss-Newton iteration method is used to determine main axes of the three-dimensional ellipsoid approximating a peach. Three independent photos displaying the peach as ground, side, and front view are used as data sources. System MAPLE 11 was used as a computer environment. A practical example is presented in order to demonstrate the usage of all required commands. The quality of approximation is evaluated as a final part of the paper.

Three tabu search methods for the MI-FAP applied to 802.11 networks

Sacha Varone, Nicolas Zufferey (2008)

RAIRO - Operations Research - Recherche Opérationnelle

Wireless LAN using IEEE 802.11 networks are now widely deployed at home by residential users or in hot spots by telecommunication operators. A hot spot is a place where a set of access points (APs) are located nearby each other and can serve many users. Since perturbations can degrade the quality of the signal, a careful channel assignment to each AP has to be done. Channel assignment of APs at hot spots, and more generally setup configuration and management, is still often done manually. In this...

Three tabu search methods for the MI-FAP applied to 802.11 networks

Sacha Varone, Nicolas Zufferey (2009)

RAIRO - Operations Research

Wireless LAN using IEEE 802.11 networks are now widely deployed at home by residential users or in hot spots by telecommunication operators. A hot spot is a place where a set of access points (APs) are located nearby each other and can serve many users. Since perturbations can degrade the quality of the signal, a careful channel assignment to each AP has to be done. Channel assignment of APs at hot spots, and more generally setup configuration and management, is still often done manually. In this...

Three-dimensional numerical model of neutron flux in hex-Z geometry

Hanuš, Milan, Berka, Tomáš, Brandner, Marek, Kužel, Roman, Matas, Aleš (2008)

Programs and Algorithms of Numerical Mathematics

We present a method for solving the equations of neutron transport with discretized energetic dependence and angular dependence approximated by the diffusion theory. We are interested in the stationary solution that characterizes neutron fluxes within the nuclear reactor core in an equilibrium state. We work with the VVER-1000 type core with hexagonal fuel assembly lattice and use a nodal method for numerical solution. The method effectively combines a whole-core coarse mesh calculation with a more...

Three-dimensional reconstruction from projections

Jiří Jelínek, Karel Segeth, T. R. Overton (1985)

Aplikace matematiky

Computerized tomograhphy is a technique for computation and visualization of density (i.e. X- or γ -ray absorption coefficients) distribution over a cross-sectional anatomic plane from a set of projections. Three-dimensional reconstruction may be obtained by using a system of parallel planes. For the reconstruction of the transverse section it is necessary to choose an appropriate method taking into account the geometry of the data collection, the noise in projection data, the amount of data, the...

Time discretizations for evolution problems

Miloslav Vlasák (2017)

Applications of Mathematics

The aim of this work is to give an introductory survey on time discretizations for liner parabolic problems. The theory of stability for stiff ordinary differential equations is explained on this problem and applied to Runge-Kutta and multi-step discretizations. Moreover, a natural connection between Galerkin time discretizations and Runge-Kutta methods together with order reduction phenomenon is discussed.

Time domain computational modelling of 1D arterial networks in monochorionic placentas

Victoria E. Franke, Kim H. Parker, Ling Y. Wee, Nicholas M. Fisk, Spencer J. Sherwin (2003)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

In this paper we outline the hyperbolic system of governing equations describing one-dimensional blood flow in arterial networks. This system is numerically discretised using a discontinuous Galerkin formulation with a spectral/ h p element spatial approximation. We apply the numerical model to arterial networks in the placenta. Starting with a single placenta we investigate the velocity waveform in the umbilical artery and its relationship with the distal bifurcation geometry and the terminal resistance....

Currently displaying 421 – 440 of 543