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Full-Text Articles in Non-linear Dynamics
Application Of Symplectic Integration On A Dynamical System, William Frazier
Application Of Symplectic Integration On A Dynamical System, William Frazier
Electronic Theses and Dissertations
Molecular Dynamics (MD) is the numerical simulation of a large system of interacting molecules, and one of the key components of a MD simulation is the numerical estimation of the solutions to a system of nonlinear differential equations. Such systems are very sensitive to discretization and round-off error, and correspondingly, standard techniques such as Runge-Kutta methods can lead to poor results. However, MD systems are conservative, which means that we can use Hamiltonian mechanics and symplectic transformations (also known as canonical transformations) in analyzing and approximating solutions. This is standard in MD applications, leading to numerical techniques known as symplectic …
The Sir Model When S(T) Is A Multi-Exponential Function., Teshome Mogessie Balkew
The Sir Model When S(T) Is A Multi-Exponential Function., Teshome Mogessie Balkew
Electronic Theses and Dissertations
The SIR can be expressed either as a system of nonlinear ordinary differential equations or as a nonlinear Volterra integral equation. In general, neither of these can be solved in closed form. In this thesis, it is shown that if we assume S(t) is a finite multi-exponential, i.e. function of the form S(t) = a+ ∑nk=1 rke-σkt or a logistic function which is an infinite-multi-exponential, i.e. function of the form S(t) = c + a/b+ewt, then …
Non-Classical Symmetry Solutions To The Fitzhugh Nagumo Equation., Arash Mehraban
Non-Classical Symmetry Solutions To The Fitzhugh Nagumo Equation., Arash Mehraban
Electronic Theses and Dissertations
In Reaction-Diffusion systems, some parameters can influence the behavior of other parameters in that system. Thus reaction diffusion equations are often used to model the behavior of biological phenomena. The Fitzhugh Nagumo partial differential equation is a reaction diffusion equation that arises both in population genetics and in modeling the transmission of action potentials in the nervous system. In this paper we are interested in finding solutions to this equation. Using Lie groups in particular, we would like to find symmetries of the Fitzhugh Nagumo equation that reduce this non-linear PDE to an Ordinary Differential Equation. In order to accomplish …
A Variation Of The Carleman Embedding Method For Second Order Systems., Charles Nunya Dzacka
A Variation Of The Carleman Embedding Method For Second Order Systems., Charles Nunya Dzacka
Electronic Theses and Dissertations
The Carleman Embedding is a method that allows us to embed a finite dimensional system of nonlinear differential equations into a system of infinite dimensional linear differential equations. This technique works well when dealing with first-order nonlinear differential equations. However, for higher order nonlinear ordinary differential equations, it is difficult to use the Carleman Embedding method. This project will examine the Carleman Embedding and a variation of the method which is very convenient in applying to second order systems of nonlinear equations.
Qualitative Models Of Neural Activity And The Carleman Embedding Technique., Azamed Yehuala Gezahagne
Qualitative Models Of Neural Activity And The Carleman Embedding Technique., Azamed Yehuala Gezahagne
Electronic Theses and Dissertations
The two variable Fitzhugh Nagumo model behaves qualitatively like the four variable Hodgkin-Huxley space clamped system and is more mathematically tractable than the Hodgkin Huxley model, thus allowing the action potential and other properties of the Hodgkin Huxley system to be more readily be visualized. In this thesis, it is shown that the Carleman Embedding Technique can be applied to both the Fitzhugh Nagumo model and to Van der Pol's model of nonlinear oscillation, which are both finite nonlinear systems of differential equations. The Carleman technique can thus be used to obtain approximate solutions of the Fitzhugh Nagumo model and …
Rocket Powered Flight As A Perturbation To The Two-Body Problem., Clayton Jeremiah Clark
Rocket Powered Flight As A Perturbation To The Two-Body Problem., Clayton Jeremiah Clark
Electronic Theses and Dissertations
The two body problem and the rocket equation r̈ + ∊ α ṙ + k/r3r = 0 have been expressed in numerous ways. However, the combination of the rocket equation with the two-body problem has not been studied to any degree of depth due to the intractability of the resulting non-linear, non-homogeneous equations. The goal is to use perturbation techniques to approximate solutions to the combined two-body and rocket equations.