Asynchronous relaxed iterative methods for solving linear systems of equations

I.AsynchronousRelaxedIterativeMethodsMoreandmorelargeorverylargescaleproblemsofscientificcomputationhavebeenproposedandarebeingproposedinmanyimportantfieldsofscienceandengineering.Manyoftheseproblemsresultinsolvinglargeorverylargelinearalgebraicsystemsofe…     

Sufficient conditions of the various stabilities of the linear time-varying delayed differential equations

Due to the appearance and the study of the ornithopter and flexible-wing micro air vehicles, etc., the time-varying systems become more and more important and ubiquitous in the study of the mechanics. In this letter, the sufficient conditions of the uniform asymptotic stability are first presented for the delayed time-varying linear differential equations with any time delay by employing the Dini derivative, Lozinskii measure and the generalized scalar Halanay delayed differential inequality. They are especially based on the estimation of the arbitrary solutions but not the fundamental solution matrix since their solutions' space is infinite-dimensional. Then some sufficient conditions of the stability, asymptotic stability and uniform asymptotic stability of the delayed time-varying linear system with a sufficiently small time delay are reported by employing Taylor expansion and Dini derivative. It implies that these stabilities can be guaranteed by the Lozinskii measure of the matrix composing of the time delay and the coefficient matrices of the system.     

Cauchy problem for one class of pseudodifferential systems with smooth symbols

For one class of pseudodifferential systems with smooth time-dependent symbols, we study properties of the fundamental matrix of solutions. We formulate sufficient and, for some systems, necessary conditions for the correct solvability of the Cauchy problem with generalized initial data. We also construct spaces of test and generalized functions that generalize certain classical spaces. __________ Translated from Neliniini Kolyvannya, Vol. 9, No. 4, pp. 502–524, October–December, 2006.     

Passivity analysis of delayed neural networks with discontinuous activations via differential inclusions

Without assuming the boundedness and monotonicity of neuron activations, we investigate passivity of delayed neural networks with discontinuous activations. Based on differential inclusion theory, sufficient conditions are established in form of linear matrix inequality by employing the generalized Lyapunov approach. In addition, a kind of control input is designed to stabilize neural network with activation functions having special form. Finally, some numerical examples are proposed to show the effectiveness of developed results.     

A quasi-velocity-based nonlinear controller for rigid manipulators

The problem of position control in the operational space of a robot manipulator is addressed in the paper. The proposed controller is based on equations of motion expressed in terms of normalized generalized velocity components (NGVC) which result from decomposition of the manipulator inertia matrix. The sufficient conditions for global exponential stability of the system under the controller are given. It is shown that using the controller an further insight into the system dynamics is possible. The proposed control algorithm is tested via simulation on a spatial manipulator with three degrees of freedom.     

Solution of two-dimensional scattering problem in piezoelectric/piezomagnetic media using a polarization method

Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezo-magnetic "comparison body" is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green's function, which is ob-tained using the Radon transform. The expression is further simplified under condi-tions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelec-tric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.     

Second-order consensus seeking in directed networks of multi-agent dynamical systems via generalized linear local interaction protocols

This paper focuses on the analytical study of final consensus convergence state of multi-agent dynamical systems by using a kind of generalized linear local interaction protocols. All the agents in the fixed directed network topology are governed by double-integrator dynamics. Almost all the existing linear local interaction consensus protocols can be considered as special cases of the present paper. By combining the algebraic graph theory and the matrix theory, some necessary and sufficient conditions are derived for reaching the second-order consensus. Moreover, the finial consensus convergence states of all agents are also be analytically determined. According to the obtained results, it is found that both the linear gains and the eigenvalues of the Laplacian matrix associated with the directed network topology play key roles in reaching consensus. Finally, the effectiveness and correctness of our theoretical findings are demonstrated by some numerical examples.     

CONTINUITY OF GENERALIZED INVERSES OF LINEAR OPERATORS IN BANACH SPACES AND ITS APPLICATIONS

The perturbation problem of generalized inverse is studied. And some new stability characteristics of generalized inverses were presented. It was also proved that the stability characteristics of generalized inverses were independent of the choice of the generalized inverse. Based on this result, two sufficient and necessary conditions for the lower semi-continuity of generalized inverses as the set-valued mappings are given.     

Generalized synchronization of discrete systems

Generalized synchronization of two discrete systems was discussed. By constructing appropriately nonlinear coupling terms, some sufficient conditions for determining the generalized synchronization between the drive and response systems were derived. In a positive invariant and bounded set, many chaotic maps satisfy the sufficient conditions. The effectiveness of the sufficient conditions is illustrated by three examples.     

The scattering of electroelastic waves by an ellipsoidal inclusion in piezoelectric medium

The scattering problem for a single ellipsoidal piezoelectric inclusion embedded in piezoelectric medium is investigated. Based on the polarization method, the extended displacements are expressed in terms of integral equations, whose kernels are obtained from the Green’s functions of homogenous matrix. In this paper, the 3D dynamic Green’s functions are derived by means of the Radon transform technique. To illustrate the use of the equations, scattering by a piezoelectric, ellipsoidal inhomogeneity in a piezoelectric medium is considered in the low frequency and an asymptotic formula for this scattering cross-section is obtained. Numerical results of the scattering cross-sections are carried out for a spheroidal BaTiO₃-inclusion in a PZT-5H-matrix.     

ON SOME PROPERTIES OF LIENARD SYSTEMS

ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｎｓｉｄｅｒａｇｅｎｅｒａｌｉｚｅｄＬｉｅｎａｒｄｓｙｓｔｅｍｓｏｆｔｈｅｆｏｒｍ ｘ=ｈ(ｙ) -Ｆ(ｘ) , ｙ=-ｇ(ｘ) ,( 1 )ｗｈｅｒｅｔｈｅｆｕｎｃｔｉｏｎｓＦ ,ｇａｎｄｈａｒｅＬｉｐｓｃｈｉｔｚｃｏｎｔｉｎｕｏｕｓａｎｄｓａｔｉｓｆｙＦ( 0 ) =ｈ( 0 ) =0 ,ｘｇ(ｘ) >0 ,　　ｘ≠ 0 . ( 2 )Ｔｈｅｒｅｈａｖｅｂｅｅｎｍａｎｙｓｔｕｄｉｅｓｆｏｒｌｏｃａｌａｎｄｇｌｏｂａｌｐｒｏｐｅｒｔｉｅｓｏｆｓｏｌｕｔｉｏｎｓｆｏｒｓｙｓｔｅｍ ( 1 ) ,ｓｅｅ[1 -9] .ＳｅｔＣ+=(ｘ,ｙ)｜ｈ(ｙ…     

The symmetry and loading-independency of multiple inclusions enclosing uniform stresses in an infinite elastic plane

The identification of multiple interacting inclusions with uniform internal stresses in an infinite elastic matrix subjected to a uniform remote loading is of fundamental importance in the mechanics and design of particulate composite materials. In anti-plane shear and plane deformations, certain sufficient conditions have been established in the literature which guarantee uniform internal stresses inside multiple interacting inclusions displaying various symmetries when the matrix is subjected to specific uniform remote loading. Correspondingly, sufficient conditions which allow for the design of multiple interacting inclusions independent of any specific form of (uniform) remote loading have also been established. In this paper, we demonstrate rigorously that, in all cases, these sufficient conditions are also necessary conditions and indeed allow for the identification of all possible collections of such inclusions.     

Conditions for the existence of a complete set of real modes for a damping vibration system

In this paper, a general damping system is transformed into an equivalent undamped system according to the transformation of general coordinates for a matrix function. The necessary and sufficient conditions for the transformability are presented, which become, after supplementing another condition as suggested, the conditions for decoupling the damping matrix of a general damping vibration system. So the Caughey's condition is insufficient for determining if a damping matrix of a general system can be decoupled.     

Second-Order Nonlinear Cauchy Problems in a Four-Dimensional Space

We consider a general second-order Cauchy problem in a four-dimensional space and establish sufficient conditions for its integrability by a generalized Lie-series method.     

Blow-up of solution for a generalized Boussinesq equation

This paper studies the initial boundary value problem for a generalized Boussinesq equation and proves the existence and uniqueness of the local generalized solution of the problem by using the Galerkin method.Moreover,it gives the sufficient conditions of blow-up of the solution in finite time by using the concavity method.     

A unified compatibility method for exact solutions of non-linear flow models of Newtonian and non-Newtonian fluids

Criteria are established for higher order ordinary differential equations to be compatible with lower order ordinary differential equations. Necessary and sufficient compatibility conditions are derived which can be used to construct exact solutions of higher order ordinary differential equations subject to lower order equations. We provide the connection to generalized groups through conditional symmetries. Using this approach of compatibility and generalized groups, new exact solutions of non-linear flow problems arising in the study of Newtonian and non-Newtonian fluids are derived. The ansatz approach for obtaining exact solutions for non-linear flow models of Newtonian and non-Newtonian fluids is unified with the application of the compatibility and generalized group criteria.     

Finite-time stability analysis of fractional-order complex-valued memristor-based neural networks with time delays

In this paper, the problem of finite-time stability of fractional-order complex-valued memristor-based neural networks (NNs) with time delays is extensively investigated. We first initiate the fractional-order complex-valued memristor-based NNs with the Caputo fractional derivatives. Using the theory of fractional-order differential equations with discontinuous right-hand sides, Laplace transforms, Mittag-Leffler functions and generalized Gronwall inequality, some new sufficient conditions are derived to guarantee the finite-time stability of the considered fractional-order complex-valued memristor-based NNs. In addition, some sufficient conditions are also obtained for the asymptotical stability of fractional-order complex-valued memristor-based NNs. Finally, a numerical example is presented to demonstrate the effectiveness of our theoretical results.     

Initial value problem for a class of fourth-order nonlinear wave equations

In this paper, existence and uniqueness of the generalized global solution and the classical global solution to the initial value problem for a class of fourth-order nonlinear wave equations are studied in the fractional order Sobolev space using the contraction mapping principle and the extension theorem. The sufficient conditions for the blow up of the solution to the initial value problem are given.     

General existence theorems for unilateral problems in continuum mechanics

The problem of minimizing a possibly non-convex and non-coercive functional is studied. Either necessary or sufficient conditions for the existence of solutions are given, involving a generalized recession functional, whose properties are discussed thoroughly. The abstract results are applied to find existence of equilibrium configurations of a deformable body subject to a system of applied forces and partially constrained to lie inside a possibly unbounded region.