Spatiotemporal Chaotic Dynamics of Solitons with Internal Structure in the Presence of Finite-Width Inhomogeneities

We present an analytical and numerical study of the Klein–Gordon kink-soliton dynamics in inhomogeneous media. In particular, we study an external field that is almost constant for the whole system but that changes its sign at the center of coordinates and a localized impurity with finite-width. The soliton solution of the Klein–Gordon-like equations is usually treated as a structureless point-like particle. A richer dynamics is unveiled when the extended character of the soliton is taken into account. We show that interesting spatiotemporal phenomena appear when the structure of the soliton interacts with finite-width inhomogeneities. We solve an inverse problem in order to have external perturbations which are generic and topologically equivalent to well-known bifurcation models and such that the stability problem can be solved exactly. We also show the different quasiperiodic and chaotic motions the soliton undergoes as a time-dependent force pumps energy into the traslational mode of the kink and relate these dynamics with the excitation of the shape modes of the soliton.     

Analytical studies of the steady solution for optical soliton equation with higher-order dispersion and nonlinear effects

The exact analytical solution of the optical soliton equation with higher-order dispersion and nonlinear effects has been obtained by the method of separating variables. The new type of optical solitary wave solution, which is quite different from the bright and dark soliton solutions, has been found under two special cases. The stability of the solitary wave solutions for the optical soliton equation is discussed. Some new conclusion of the stability are obtained, for the solitary wave solutions of the nonlinear wave equations, by using the Liapunov direct method.     

Linear Stability of Miscible Displacement Processes in Porous Media in the Absence of Dispersion

The linear stability of miscible displacement processes in porous media is examined in the absence of diffusion and dispersion. Bounds for the rate of growth of the disturbance are derived. The asymptotic behavior of the rate of growth as a function of the wavenumber of the disturbance and the mobility profile characteristics is obtained for both small and large wavenumbers. A closed-form solution is also presented for a particular mobility profile. It is shown that such displacement processes are linearly unstable in the case when the mobility profile contains any segments of decreasing mobility, and marginally stable in the opposite case. The effect of gravity on linear stability, in the case of compressible flows, is also briefly discussed.     

Asymptotics for Supersonic Soliton Propagation in the Toda Lattice Equation

We study the problem of the adjustment of an initial condition to an exact supersonic soliton solution of the Toda latice equation. Also, we study the problem of soliton propagation in the Toda lattice with slowly varying mass impurities. In both cases we obtain the full numerical solution of the soliton evolution and we develop a modulation theory based on the averaged Lagrangian of the discrete Toda equation. Unlike previous problems with coherent subsonic solutions we need to modify the averaged Lagrangian to obtain the coupling between the supersonic soliton and the subsonic linear radiation. We show how this modified modulation theory explains qualitatively in simple terms the evolution of a supersonic soliton in the presence of impurities. The quantitative agreement between the modulation solution and the numerical result is good.     

Stability theory for periodic pulse train solutions of the nonlinear Schrodinger equation

The problem of the stability of periodic and quasiperiodic trainsof soliton pulses in the nonlinear Schrödinger equationis examined using linearized perturbation theory. When the quasiperiodicsoliton pulse train is subjected to perturbations of positionor phase, there are both stable and unstable regions of theparameter space. The stability exponents of these perturbationsare determined in the asymptotic case of large separation betweenthe solitons.     

On stability and L p solutions of ordinary differential equations

Summary The usual definition of the stability of a solution of a system of ordinary differential equations is extended by introducing two positive control functions. These functions are used to control the rate of growth of the in?tial position of the solution and the rate of growth of the solution. Definitions and results are also given for the corresponding analogues of boundedness, weak boundedness, and uniform properties of the sotions of differential equations. The problem of determining when solutions of certain linear and weakly nonlinear differential equations lie in a modified Lp-space is also considered. This research was supported by the National Science Foundation under grant GP-8921. Entrata in Redazione il 13 maggio 1969.     

Dynamic of DNA's possible impact on its damage

E. Sanchez‐Palencia In this paper, we investigate the dynamic of DNA described via DNA double‐stranded model with transverse and longitudinal motions. This model admits solitary, soliton, periodic, or chirped wave solution. It is justified that the most admissible physical solution is the soliton or chirped wave solution. The stability analysis of all these solutions is performed by using the Sturm–Liouville problem and the topological invariance. We found that soliton and chirped waves are unstable so that the unbounded amplitude may occur. In the view of these models, damage of DNA membrane or bases may occur under small disturbance. Also, the suggested models will be indispensable when inhomogeneity or medium dissipation is taken into account. Copyright © 2015 John Wiley & Sons, Ltd.     

Rotationally symmetric translating soliton of H~k-flow

This paper mainly considers the translating soliton of H k-flow for k > 0.We give the asymptotic expression of the entire rotationally symmetric translating soliton,and obtain non-convex Wing-like solution as well as two barrier solutions.Moreover,we show that the solution with polynomial growth keeps its growth rate when evolution.     

Nonlinear evolution of a first mode oblique wave in a compressible boundary layer: I. Heated/cooled walls

The nonlinear stability of an oblique mode propagating in atwo-dimensional compressible boundary layer is considered underthe long wavelength approximation. The growth rate of the waveis assumed to be small so that the ideas of unsteady nonlinearcritical layers can be applied. It is shown that the spatial/temporalevolution of the mode is governed by a pair of coupled unsteadynonlinear equations for the disturbance vorticity and density.Expressions for the linear growth rate show clearly the effectsof wall heating and cooling, and in particular how heating destabilizesthe boundary layer for these long wavelength inviscid modesat O(1) Mach numbers. A generalized expression for the lineargrowth rate is obtained and is shown to compare very well fora range of frequencies and wave angles at moderate Mach numberswith full numerical solutions of the linear stability problem.The numerical solution of the nonlinear unsteady critical layerproblem using a novel method based on Fourier decompositionand Chebyshev collocation is discussed and some results arepresented.     

Instability of solitons under flexure and twist of an elastic rod

We study the stability of planar soliton solutions of equations describing the dynamics of an infinite inextensible unshearable rod under three-dimensional spatial perturbations. As a result of linearization about the soliton solution, we obtain an inhomogeneous scalar equation. This equation leads to a generalized eigenvalue problem. To establish the instability, we must verify the existence of an unstable eigenvalue (an eigenvalue with a positive real part). The corresponding proof of the instability is done using a local construction of the Evans function depending only on the spectral parameter. This function is analytic in the right half of the complex plane and has at least one zero on the positive real axis coinciding with an unstable eigenvalue of the generalized spectral problem.     

A Spectral Method for a Class of System of Multi-Dimensional Nonlinear Wave Equations

In [1,2], the problem of three-dimensional soliton of a class of system for three-dimensional nonlinear wave equations was investigated, and the existence and stability of three-dimensional soliton was proved. In [3] the system discusses in [1,2] was generalized and a more general class of system of multi-dimensional nonlinear wave equations were studied. It was proved that the solution of its initial-boundary value problem was well posed under some conditions. This system has been studied by the finite difference method and the finite element method [4,5]. In this paper, we take the trigonometric functions as a basis to derive a spectral method for the system and give a strict error analysis in theory.     

Optical solitons in a power law media with fourth order dispersion

In this paper, a closed form optical soliton solution is obtained for the nonlinear Schrödinger’s equation with fourth order dispersion in a power law media. The solitary wave ansatze is used to carry out the integration of this equation. Finally, a numerical simulation is given for the closed form soliton solution.     

Peakon,pseudo‐peakon,cuspon and smooth solitons for a nonlocal Kerr‐like media

This paper presents all possible exact explicit peakon, pseudo‐peakon, cuspon and smooth solitary wave solutions for a nonlocal Kerr‐like media. We apply the method of dynamical systems to analyze the dynamical behavior of the traveling wave solutions and their bifurcations depending on the parameters of the system. We present peakon, pseudo‐peakon, cuspon soliton solution in an explicit form. We also have obtained smooth soliton. Mathematical analysis and numeric graphs are provided for those soliton solutions of the nonlocal Kerr‐like media. Copyright © 2016 John Wiley & Sons, Ltd.     

Higher-Order Solitons in the N-Wave System

The soliton dressing matrices for the higher-order zeros of the Riemann–Hilbert problem for the N -wave system are considered. For the elementary higher-order zero, that is, whose algebraic multiplicity is arbitrary but the geometric multiplicity is 1, the general soliton dressing matrix is derived. The theory is applied to the study of higher-order soliton solutions in the three-wave interaction model. The simplest higher-order soliton solution is presented. In the generic case, this solution describes the breakup of a higher-order pumping wave into two higher-order elementary waves, and the reverse process. In non-generic cases, this solution could describe (i) the merger of a pumping sech wave and an elementary sech wave into two elementary waves (one sech and the other one higher order); (ii) the breakup of a higher-order pumping wave into two elementary sech waves and one pumping sech wave; and the reverse processes. This solution could also reproduce fundamental soliton solutions as a special case.     

Solitary waves in dusty plasmas with variable dust charge and two temperature ions

Propagation of nonlinear waves in dusty plasmas with variable dust charge and two temperature ions is analyzed. The Kadomtsev–Petviashivili (KP) equation is derived by using the reductive perturbation theory. A Sagdeev potential for this system has been proposed. This potential is used to study the stability conditions and existence of solitonic solutions. Also, it is shown that a rarefactive soliton can be propagates in most of the cases. The soliton energy has been calculated and a linear dispersion relation has been obtained using the standard normal-modes analysis. The effects of variable dust charge on the amplitude, width and energy of the soliton and its effects on the angular frequency of linear wave are discussed too. It is shown that the amplitude of solitary waves of KP equation diverges at critical values of plasma parameters. Solitonic solutions of modified KP equation with finite amplitude in this situation are derived.     

Instability of solitary waves in non-linear composite media

A problem on the dynamic instability of soliton solutions (solitary waves) of Hamilton's equations, describing plane waves in non-linear elastic composite media with or without anisotropy, is considered. In the anisotropic case, there are two two-parameter families of solitary waves: fast and slow and, when there is no anisotropy, there is one three-parameter family. A classification of the instability of solitary waves of the fast family in the anisotropic case and of representatives of families of solitary waves, the velocities of which lie outside of the range of stability when there is anisotropy and when there is no anisotropy, is given on the basis of a numerical solution of a Cauchy problem for the model equations. In this paper, the fundamental equations describing plane waves in non-linear, anisotropic, elastic composites are derived, the Hamilton form of the basic equations is presented, the symmetries in the anisotropic and isotropic cases are considered, the conserved quantities and the soliton solutions, that is, the solitary waves are presented, the nature of the instability of representatives of all three families is investigated, brief formulation of the results is presented and problems of the instability of the fast family in the anisotropic case and of representatives of the families, the velocities of which lie outside of the range of stability in the presence and absence of anisotropy (explosive instability), are discussed.     

Cost optimal periodic train scheduling

For real world railroad networks, we consider minimizing operational cost of train schedules which depend on choosing different train types of diverse speed and cost. We develop a mixed integer linear programming model for this train scheduling problem. For practical problem sizes, it seems to be impossible to directly solve the model within a reasonable amount of time. However, suitable decomposition leads to much better performance. In the first part of the decomposition, only the train type related constraints stay active. In the second part, using an optimal solution of this relaxation, we select and fix train types and try to generate a train schedule satisfying the remaining constraints. This decomposition idea provides the cornerstone for an algorithm integrating cutting planes and branch-and-bound. We present computational results for railroad networks from Germany and the Netherlands.     

Nonlinear scattering: The states which are close to a soliton

We assume that the nonlinear Schroedinger equation with sufficiently general nonlinearity admits solutions of the soliton type. The Cauchy problem with initial data close to a soliton is considered. We also assume that the linearization of the equation in the vicinity of the soliton possesses only a real spectrum. The main result claims that the asymptotic behavior of the solution as t→+∞ is given by the sum of a soliton with deformed parameters and a dispersive tail, i.e., a solution of the linear Schroedinger equation. The case of the minimal spectrum has been considered in the previous paper. Bibliography: 1 title. Dedicated to O. A. Ladyzhenskaya on the occasion of the jubilee Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 200, 1992, pp. 38–50. Translated by G. S. Perelman     

Stability of linear time-varying delay systems and applications to control problems

This paper deals with the stability of a class of linear time-varying systems with multiple delays. Using the Lyapunov function method, we give sufficient delay-dependent conditions for the exponential stability with a given convergence rate, which are described in terms of linear matrix inequalities (LMI) and the solution of Riccati differential equations (RDE). The results are applied to the problem of stabilization of linear time-varying control systems with multiple delays. Numerical examples are given to illustrate the results.     

Freight transportation in railway networks with automated terminals: A mathematical model and MIP heuristic approaches

In this paper we propose a planning procedure for serving freight transportation requests in a railway network with fast transfer equipment at terminals. We consider a transportation system where different customers make their requests (orders) for moving boxes, i.e., either containers or swap bodies, between different origins and destinations, with specific requirements on delivery times. The decisions to be taken concern the route (and the corresponding sequence of trains) that each box follows in the network and the assignment of boxes to train wagons, taking into account that boxes can change more than one train and that train timetables are fixed.The planning procedure includes a pre-analysis step to determine all the possible sequences of trains for serving each order, followed by the solution of a 0-1 linear programming problem to find the optimal assignment of each box to a train sequence and to a specific wagon for each train in the sequence. This latter is a generalized assignment problem which is NP-hard. Hence, in order to find good solutions in acceptable computation times, two MIP heuristic approaches are proposed and tested through an experimental analysis considering realistic problem instances.