Displaying 1121 – 1140 of 1850

Showing per page

Numerical optimization of parameters in systems of differential equations

Martínek, Josef, Kučera, Václav (2023)

Programs and Algorithms of Numerical Mathematics

We present results on the estimation of unknown parameters in systems of ordinary differential equations in order to fit the output of models to real data. The numerical method is based on the nonlinear least squares problem along with the solution of sensitivity equations corresponding to the differential equations. We will present the performance of the method on the problem of fitting the output of basic compartmental epidemic models to data from the Covid-19 epidemic. This allows us to draw...

Numerical simulation of blood flows through a porous interface

Miguel A. Fernández, Jean-Frédéric Gerbeau, Vincent Martin (2008)

ESAIM: Mathematical Modelling and Numerical Analysis

We propose a model for a medical device, called a stent, designed for the treatment of cerebral aneurysms. The stent consists of a grid, immersed in the blood flow and located at the inlet of the aneurysm. It aims at promoting a clot within the aneurysm. The blood flow is modelled by the incompressible Navier-Stokes equations and the stent by a dissipative surface term. We propose a stabilized finite element method for this model and we analyse its convergence in the case of the Stokes...

Numerical simulation of chemotactic bacteria aggregation via mixed finite elements

Americo Marrocco (2003)

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

We start from a mathematical model which describes the collective motion of bacteria taking into account the underlying biochemistry. This model was first introduced by Keller-Segel [13]. A new formulation of the system of partial differential equations is obtained by the introduction of a new variable (this new variable is similar to the quasi-Fermi level in the framework of semiconductor modelling). This new system of P.D.E. is approximated via a mixed finite element technique. The solution algorithm...

Numerical simulation of chemotactic bacteria aggregation via mixed finite elements

Americo Marrocco (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

We start from a mathematical model which describes the collective motion of bacteria taking into account the underlying biochemistry. This model was first introduced by Keller-Segel [13]. A new formulation of the system of partial differential equations is obtained by the introduction of a new variable (this new variable is similar to the quasi-Fermi level in the framework of semiconductor modelling). This new system of P.D.E. is approximated via a mixed finite element technique. The solution...

Numerical simulation of surface acoustic wave actuated cell sorting

Thomas Franke, Ronald Hoppe, Christopher Linsenmann, Kidist Zeleke (2013)

Open Mathematics

We consider the mathematical modeling and numerical simulation of high throughput sorting of two different types of biological cells (type I and type II) by a biomedical micro-electro-mechanical system (BioMEMS) whose operating behavior relies on surface acoustic wave (SAW) manipulated fluid flow in a microchannel. The BioMEMS consists of a separation channel with three inflow channels for injection of the carrier fluid and the cells, two outflow channels for separation, and an interdigital transducer...

Numerical solution of a new hydrodynamic model of flocking

Kučera, Václav, Živčáková, Andrea (2015)

Programs and Algorithms of Numerical Mathematics

This work is concerned with the numerical solution of a hydrodynamic model of the macroscopic behavior of flocks of birds due to Fornasier et al., 2011. The model consists of the compressible Euler equations with an added nonlocal, nonlinear right-hand side. As noticed by the authors of the model, explicit time schemes are practically useless even on very coarse grids in 1D due to the nonlocal nature of the equations. To this end, we apply a semi-implicit discontinuous Galerkin method to solve the...

Numerical study of the stopping of aura during migraine

C. Pocci, A. Moussa, F. Hubert, G. Chapuisat (2010)

ESAIM: Proceedings

This work is devoted to the study of migraine with aura in the human brain. Following [6], we class migraine as a propagation of a wave of depolarization through the cells. The mathematical model used, based on a reaction-diffusion equation, is briefly presented. The equation is considered in a duct containing a bend, in order to model one of the numerous circumvolutions of the brain. For a wide set of parameters, one can establish the existence...

Nutrient-phytoplankton-zooplankton interaction with variable yields

Joydeb Bhattacharyya, Samares Pal (2013)

Applicationes Mathematicae

A three dimensional predator-prey-resource model is proposed and analyzed to study the dynamics of the system with resource-dependent yields of the organisms. Our analysis leads to different thresholds in terms of the model parameters acting as conditions under which the organisms associated with the system cannot thrive even in the absence of predation. Local stability of the system is obtained in the absence of one or more of the predators and in the presence of all the predators. Under appropriate...

Currently displaying 1121 – 1140 of 1850