Sökning: "Per Lötstedt"
Visar resultat 16 - 20 av 29 avhandlingar innehållade orden Per Lötstedt.
16. Stochastic Simulation of Reaction-Diffusion Processes
Sammanfattning : Numerical simulation methods have become an important tool in the study of chemical reaction networks in living cells. Many systems can, with high accuracy, be modeled by deterministic ordinary differential equations, but other systems require a more detailed level of modeling. LÄS MER
17. Runge–Kutta Time Step Selection for Flow Problems
Sammanfattning : Optimality is studied for Runge-Kutta iteration for solving steady-state and time dependent flow problems. For the former type an algorithm for determining locally optimal time steps is developed, based on the fact that the squared norm of the residual produced by an m-stage scheme is a 2m-degree polynomial, the coefficients of which can be computed from scalar products of Krylov subspace vectors. LÄS MER
18. Boundary Layer Approximate Approximations and Cubature of Potentials in Domains
Sammanfattning : The goal of this thesis is to develop efficient numerical algorithms for approximation of functions defined on domains and apply these algorithms to obtain accurate semi-analytic cubature formulae for various integral operators. These algorithms are based on the method of "approximate approximations", introduced by V. Maz'ya in 1991. LÄS MER
19. Numerical methods for waveguide modelling
Sammanfattning : Waveguides are used to transmit electromagnetic signals. Their geometry is typically long and slender. This particular shape can be used in the design of efficient computational methods. Only special modes are transmitted and eigenvalue and eigenvector analysis becomes important. LÄS MER
20. Stochastic Simulation of Multiscale Reaction-Diffusion Models via First Exit Times
Sammanfattning : Mathematical models are important tools in systems biology, since the regulatory networks in biological cells are too complicated to understand by biological experiments alone. Analytical solutions can be derived only for the simplest models and numerical simulations are necessary in most cases to evaluate the models and their properties and to compare them with measured data. LÄS MER