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Search Results: 1 - 10 of 27681 matches for " Jean Marie Linhart "
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Fast Blow Up in the (4+1)-dimensional Yang Mills Model and the(2+1)-dimensional S^2 Sigma Model
Jean Marie Linhart
Physics , 1999,
Abstract: We study singularity formation in spherically symmetric solitons of the (4+1) dimensional Yang Mills model and the charge two sector of the (2+1) dimensional S^2 sigma model, also known as $\IC P^1$ wave maps, in the adiabatic limit. These two models are very similar. Studies are performed numerically on radially symmetric solutions using an iterative finite differencing scheme. Predictions for the evolution toward a singularity are made from an effective Lagrangian and confirmed numerically. In both models a characterization of the shape of a time slice f(r,T) with T fixed is provided, and ultimately yields an new approximate solutions to the differential equations that becomes exact in the adiabatic limit.
Slow Blow Up in the (2+1)-dimensional S^2 Sigma Model
Jean Marie Linhart
Physics , 1999,
Abstract: We study singularity formation in spherically symmetric solitons of the charge one sector of the (2+1) dimensional S^2 sigma model, also known as $\IC P^1$ wave maps, in the adiabatic limit. These equations are non-integrable, and so studies are performed numerically on radially symmetric solutions using an iterative finite differencing scheme. Analytic estimates are made by using an effective Lagrangian cutoff outside a ball of fixed radius. We show the geodesic approximation is valid when the cutoff is applied, with the cutoff approaching infinity linearly as the reciprocal of the initial velocity. Additionally a characterization of the shape of a time slice f(r,T) with T fixed is provided.
Numerical investigations of singularity formation in non-linear wave equations in the adiabatic limit
Jean Marie Linhart
Physics , 2001,
Abstract: This dissertation deals with singularity formation in spherically symmetric solutions of the hyperbolic Yang Mills equations in (4+1) dimensions and in spherically symmetric solutions of C P^1 wave maps in (2+1) dimensions. These equations have known moduli spaces of time-independent (static) solutions. Evolution occurs close to the moduli space of static solutions. The evolution is modeled numerically using an iterative finite differencing scheme, and modeling is done close to the adiabatic limit, i.e., with small velocities. The stability of the numerical scheme is analyzed and growth is shown to be bounded, yielding a convergence estimate for the numerical scheme. The trajectory of the approach is characterized, as well as the shape of the profile at any given time during the evolution.
Fast and Slow Blowup in the S^2 Sigma Model and (4+1)-Dimensional Yang-Mills Model
Jean Marie Linhart,Lorenzo A. Sadun
Physics , 2001, DOI: 10.1088/0951-7715/15/2/301
Abstract: We study singularity formation in spherically symmetric solutions of the charge-one and charge-two sector of the (2+1)-dimensional S^2 sigma-model and the (4+1)-dimensional Yang-Mills model, near the adiabatic limit. These equations are non-integrable, and so studies are performed numerically on rotationally symmetric solutions using an iterative finite differencing scheme that is numerically stable. We evaluate the accuracy of predictions made with the geodesic approximation. We find that the geodesic approximation is extremely accurate for the charge-two sigma-model and the Yang-Mills model, both of which exhibit fast blowup. The charge-one sigma-model exhibits slow blowup. There the geodesic approximation must be modified by applying an infrared cutoff that depends on initial conditions.
Fuzzy Logic Strategy for Solving an Optimal Control Problem of Glucose and Insulin in Diabetic Human  [PDF]
Jean Marie Ntaganda
Open Journal of Applied Sciences (OJAppS) , 2013, DOI: 10.4236/ojapps.2013.37052
Abstract:

This paper aims at the development of an approach integrating the fuzzy logic strategy for a glucose and insulin in diabetic human optimal control problem. To test the efficiency of this strategy, the author proposes a numerical comparison with the indirect method. The results are in good agreement with experimental data.

Hopf Bifurcation of a Two Delay Mathematical Model of Glucose and Insulin during Physical Activity  [PDF]
Jean Marie Ntaganda
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.42006
Abstract: In this paper, we are interested in looking for Hopf bifurcation solutions for mathematical model of plasma glucose and insulin during physical activity. The mathematical model is governed by a system of delay differential equations. The algorithm for determining the critical delays that are appropriate for Hopf bifurcation is used. The illustrative example is taken for a 30 years old woman who practices regular three types of physical activity: walking, jogging and running fast.
Different Rationales of Coalition Formation and Incentives for Strategic Voting  [PDF]
Eric Linhart, Johannes Raabe
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.97058
Abstract:
Research on strategic voting has mainly focused on electoral system effects but largely neglected the impact of different rationales of coalition formation. Based on a formal model of rational party choice and a simulation study, we systematically investigate this impact and explore the implications. We show that the logic of the underlying coalition formation procedure clearly affects the degree to which the electorate is exposed to strategic incentives regarding the vote choice. The key implications are that sincere voting is more often in the voter’s best interest if parties are policy-seeking and if there is increased uncertainty during the stage of coalition formation. Furthermore, we explore how different types of coalition formation affect strategic incentives across the policy space.
CARDIOGUI: An Interface Guide to Simulate Cardiovascular Respiratory System during Physical Activity  [PDF]
Jean Marie Ntaganda, Benjamin Mampassi
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.312275
Abstract: This paper aims at the presentation of an interface to simulate cardiovascular respiratory system. The authors are interested in the resolution of optimal control problem related to the performance of a 30 years old woman. The results show in the most case the determinant parameters of cardiovascular respiratory system reach the equilibrium value due to its controls that is heart rate and alveolar ventilation.
An Optimal Control Problem for Hypoxemic Hypoxia Tissue-Blood Carbon Dioxide Exchange during Physical Activity  [PDF]
Jean Marie Ntaganda, Benjamin Mampassi
Open Journal of Applied Sciences (OJAppS) , 2013, DOI: 10.4236/ojapps.2013.31009
Abstract:

This paper aims at solving an optimal control problem for determining the response of hypoxia to heart rate and alveolar ventilation that are cardiovascular and respiratory control respectively during a physical activity. A two nonlinear coupled ordinary differential equations is presented. The cost function of optimal control problem is discretized using the linear B-splines functions defined on a regular grid. The results show the determinant parameters stabilized at normal value.

Fuzzy Logic Approach for Solving an Optimal Control Problem of an Uninfected Hepatitis B Virus Dynamics  [PDF]
Jean Marie Ntaganda, Marcel Gahamanyi
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.69136
Abstract: We aimed in this paper to use fuzzy logic approach to solve a hepatitis B virus optimal control problem. The approach efficiency is tested through a numerical comparison with the direct method by taking the values of determinant parameters of this disease for people administrating the drugs. Final results of both numerical methods are in good agreement with experimental data.
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