ABSOLUTE OBSERVABILITIES OF NONLINEAR CONTROL SYSTEMS AND THEIR NORMAL FORMS

In this paper the concept of absolute observability of nonlinear control systems is advanced.Different from the linear time-invariant version, there are different definitions of absolute observability for nonlinear control systems.Two algorithms for maximal absolutely observable subsystems are given.Correspondingly,there are two relevant normal forms.The relations with the largest controlled invariant distribution contained in kerdh,zero dynamics etc.,are discussed from the view point of maximal absolute observabilities.     

NORMAL FORMS OF INTEGRABLE SYSTEMS AT A RESONANT SADDLE

１ＩｎｔｒｏｄｕｃｔｉｏｎａｎｄｔｈｅＲｅｓｕｌｔＣｏｎｓｉｄｅｒａｐｌａｎａｒａｎａｌｙｔｉｃｓｙｓｔｅｍｏｆｔｈｅｆｏｒｍｘ＝Ｐ（ｘ，ｙ），ｙ＝Ｑ（ｘ，ｙ），（１．１）ｗｈｅｒｅＰａｎｄＱａｒｅａｎａｌｙｔｉｃｆｕｎｃｔｉｏｎｓｉｎ（ｘ，ｙ）ｉｎ...     

h─STABILITY FOR NONLINEAR PERTURBED SYSTEMS

ｈ─ＳＴＡＢＩＬＩＴＹＦＯＲＮＯＮＬＩＮＥＡＲＰＥＲＴＵＲＢＥＤＳＹＳＴＥＭＳ￥ＳｕｎｇＫｙｕＣｈｏｉａｎｄＮａｍＪｉｐＫｏｏ（ＣｈｕｎｇｎａｍＮａｔｉｏｎａｌＵｎｉｖｅｒｓｉｔｙ，Ｋｏｒｅａ）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐｅｒ，ｗｅｏｂｔａｉ...     

C~(1,α)-PARTIAL REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS

Ｃ~（１，α）－ＰＡＲＴＩＡＬＲＥＧＵＬＡＲＩＴＹＦＯＲＮＯＮＬＩＮＥＡＲＥＬＬＩＰＴＩＣＳＹＳＴＥＭＳＴａｎｚｈｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＸｉａｍｅｎＵｎｉｖｅｒｓｉｔｙ，Ｘｉａｎｍｅｎ３６１００５，Ｃｈｉｎａ．）Ａｂ?..     

A NEW ILU PRECONDITIONER FOR BORDERED LINEAR SYSTEMS

Bordered linear systems arise from many industrial applications, such as reservoir simulation and structural engineering. Traditional ILU preconditioners which throw away the additional equations are often too crude for these systems. We describe a practical implementation of ILU preconditioners which are more accurate and more robust. The emphasis of this paper is on implementation rather than on theory.     

C~(1,α)PARTIAL REGULARITY FOR SOLUTIONS OF NONLINEAR ELLIPTIC SYSTEMS

We use the blow-up method to get the C~(1,α) partial regularity results for the following elliptic systems satisfying natural growth conditions:     

ON A CONJECTURE ABOUT NONLINEAR FILTER FOR BILINEAR SYSTEMS

Ln this note we prove that it is not possible to get a better linear filter for bilinear systems by using the updated innovation.     

A NEW SQP-FILTER METHOD PROGRAMMING FOR SOLVING NONLINEAR PROBLEMS

In [4], Fletcher and Leyffer present a new method that solves nonlinear programming problems without a penalty function by SQP-Filter algorithm. It has attracted much attention due to its good numerical results. In this paper we propose a new SQP-Filter method which can overcome Maratos effect more effectively. We give stricter acceptant criteria when the iterative points are far from the optimal points and looser ones vice-versa. About this new method, the proof of global convergence is also presented under standard assumptions. Numerical results show that our method is efficient.     

A NEW SECANT METHOD FOR NONLINEAR LEAST SQUARES PROBLEMS

This paper is concerned with the solution of the nonlinear least squares problems. A new secant method is suggested in this paper, which is based on an affine model of the objective function and updates the first-order approximation each step when the iterations proceed. We present an algorithm which combines the new secant method with Gauss-Newton method for general nonlinear least squares problems. Furthermore, we prove that this algorithm is Q-superlinearly convergent for large residual problems under mild conditions.     

ASYMPTOTIC METPOD FOR ANALYSIS OF NONLINEAR SYSTEMS WITH TWO PARAMETERS

A new asymptotic method has been worked out for the decay of autonomous, nonlinear oscillations in the case where there are two parameters and a strong static nonlinearity.     

INITIAL-OBLIQUE DERIVATIVE PROBLEMS FOR NONLINEAR PARABOLIC SYSTEMS WITH MEASURABLE COEFFICIENTS

This paper deals with some initial-oblique derivative boundary value problems for nonlinear nondivergent parabolic systems of several second order equations with measurable coefficients in multiply connected domains. Firstly, a priori estimates of solutions for the initial-boundary value problems are given, and then by using the above estimates of solutions and the Leray-Schauder theorem, the existence and uniqueness of solutions for the problems are proved.     

NEW ALTERNATING DIRECTION FINITE ELEMENT SCHEME FOR NONLINEAR PARABOLIC EQUATION

A new alternating direction (AD) finite element (FE) scheme for 3-dimensional nonlinear parabolic equation and parabolic integro-differential equation is studied. By using AD, the 3-dimensional problem is reduced to a family of single space variable problems, calculation work is simplified; by using FE, high accuracy is kept; by using various techniques for priori estimate for differential equations such as inductive hypothesis reasoning, the difficulty arising from the nonlinearity is treated. For both FE and ADFE schemes, the convergence properties are rigorously demonstrated, the optimal H1-and L2-norm space estimates and the 0((△t)2) estimate for time variable are obtained.     

A CLASS OF DECOMPOSITION METHODS FOR LARGE-SCALE SYSTEMS OF NONLINEAR EQUATIONS

This paper presents a new decomposition method for solving large-scale systems of nonlinear equations. The new method is of superlinear convergence speed and has rather less computa tional complexity than the Newton-type decomposition method as well as other known numerical methods, Primal numerical experiments show the superiority of the new method to the others.     

ITERATIVE SOLUTIONS FOR SYSTEMS OF NONLINEAR OPERATOR EQUATIONS IN BANACH SPACE

By using partial order method, the existence, uniqueness and iterative approximation of solutions for a class of systems of nonlinear operator equations in Banach space are discussed. The results obtained in this paper extend and improve recent results.     

SINGULAR PERTURBATION ON STABILITY FOR A CLASS OF NONLINEAR CONTROL SYSTEMS

1IntroductionStabilitypropertiesofSingularlyperturbedsystemshavebeenstudiedovalthepasttwoorthreede.ade,[1'21.Lyapunovmethodshavebeenwidelyemployed.Themainideaofthispaperistodecompositetheoriginalsystemstotwoseparatesllbsysterns:theso--calledreducedandboun…     

STABILITY OF DIFFERENCE SCHEMES FOR NONLINEAR PARABOLIC SYSTEMS WITH THREE DIMENSIONS

1.Introduction1).Inthepresentworkwearegoingtostudythedeferenceschemesfortheboundaryvalueproblemofthenonlinearparabolicsystemsofpartialdifferentialequationswithtwoandthreespacedimensions.Inthecaseofthreespacedimension,thenonlinearparabolicsystemisoftheformat~A(x,y,z,t,u,aamactu.)(u.. aam u..) f(x,y,z,t,aliojac,u.),(1)whereu=(altuZI',urn)istheunknownm-dimensionalvectorfunction(m3l),A(x,yiitt,u,PI,pz,ps)isagivenmXmmatrixfunction,f(x,y,itt,utpl,p2,p3)isthegivenmdimensionalvectorfunctionandalso…     

SPHERICAL NONLINEAR PULSES FOR THE SOLUTIONS OF NONLINEAR WAVE EQUATIONS Ⅱ, NONLINEAR CAUSTIC

This article discusses spherical pulse like solutions of the system of semilinear wave equations with the pulses focusing at a point and emerging outgoing in three space variables. In small initial data case, it shows that the nonlinearities have a strong effect at the focal point. Scattering operator is introduced to describe the caustic crossing. With the aid of the L∞norms, it analyzes the relative errors in approximate solutions.     

A NEW MULTI-SYMPLECTIC SCHEME FOR NONLINEAR “GOOD” BOUSSINESQ EQUATION

The Hamiltonian formulations of the linear “good“ Boussinesq (L.G.B.) equation and the multi-symplectic formulation of the nonlinear “good“ Boussinesq (N.G.B.) equation are considered. For the multi-symplectic formulation, a new fifteen-point difference scheme which is equivalent to the multi-symplectic Preissmann integrator is derived. We also present numerical experiments, which show that the symplectic and multisymplectic schemes have excellent long-time numerical behavior.     

EXISTENCE AND UNIQUENESS FOR SECOND-ORDER VECTOR BOUNDARY VALUE PROBLEM OF NONLINEAR SYSTEMS

This paper is concerned with the following second-order vector boundary value problem ：x^R=f（t,Sx,x,x＇）,0〈t〈1,x（0）=A,g（x（1）,x＇（1））=B,where x,f,g,A and B are n-vectors. Under appropriate assumptions,existence and uniqueness of solutions are obtained by using upper and lower solutions method.     

SEGREGATED VECTOR SOLUTIONS FOR NONLINEAR SCHR?DINGER SYSTEMS IN R~2

We study the following nonlinear Schrodinger system where P(τ) and Q(τ) are positive radial functions,μ 0,v 0,and β∈ R is a coupling constant.This type of system arises,particularly,in models in Bose-Einstein condensates theory.Applying a finite reduction method,we construct an unbounded sequence of nonradial positive vector solutions of segregated type when β is in some suitable interval,which gives an answer to an interesting problem raised by Peng and Wang in Remark 4.1(Arch.Ration.Mech.Anal.,208(2013),305-339).