具有扭转耦合效应的复合薄壁梁黎斯基的性质和指数稳定性(英文)

研究了具有扭转耦合效应的复合薄壁梁黎斯基的性质以及指数稳定性.首先证明该系统决定算子的预解式是紧的,且可生成群.其次,通过对该系统算子谱的渐近分析,证明了除至多有限个本征值外,其算子的谱是单重可分离的.特殊地,我们获得了自由系统的频率渐近表达式,因而利用克尔德什定理,证明了在希尔伯特状态空间中算子广义本征函数列的完备性.最后,结合黎斯基的性质及算子谱的分布证明了该系统的指数稳定性.     

一个复合系统边界反馈的Riesz基性质

该文考虑一端固定 ,一端具负荷的梁的振动问题 .证明了线性反馈的闭环系统是一个 Riesz谱系统 ,即系统存在一列广义本征函数列构成状态空间的 Riesz基 .从而系统的谱确定增长条件成立 .在此过程中 ,简单的导出了系统本征值的渐近展开式 .并因此推论出系统的指数稳定性的条件     

具一组可修复设备的系统解的适定性和稳定性

研究具一组可修复设备的系统解的适定性和稳定性.使用泛函分析方法,特别是Banach空间上的线性算子理论和C_0半群理论,证明了系统解的适定性以及正解的存在性,证明了系统解的渐近稳定性,指数稳定性以及严格占优本征值的存在性,证实了实际问题中相关假设的合理性.     

一类冷贮备可修系统的指数稳定性

研究了修理工可延误休假的冷贮备可修系统.通过选取空间及定义算子,将模型方程转化成Banach空间中抽象的Cauchy问题,运用预解正算子和C_0半群理论证明了系统动态解的存在唯一性,并通过分析系统算子的谱分布,得出系统算子的严格占优本征值及近似本征值,进而得到系统的指数稳定性.     

复杂微分网络的指数稳定性

研究树形弦网络在速度反馈控制下的指数稳定性及其控制器的有效性.用半群理论证明速度反馈控制下的闭环系统是适定的. 通过对算子谱的渐近分析, 得到在一定条件下, 系统的谱分布在平行于虚轴的带域中,并证明存在一列根向量构成Hilbert状态空间一个加括号的Riesz基, 从而系统满足谱确定增长条件.利用Riesz基性质和谱分布, 给出系统的指数稳定性结果. 提出控制器有效性的概念, 给出网络不同节点处控制器的有效性比较, 得到使树形弦网络指数稳定所需控制器的最少个数及其放置位置.     

血红细胞时滞模型的谱及其解的结构

研究一个带有时滞的血红细胞模型的解展开问题.对模型在平衡点处线性化,并利用泛函分析方法,将线性化模型写成抽象发展方程.借助半群理论证明了方程的适定性.对系统算子细致的谱分析,得到了本征值的渐近表达式.通过对算子的Riesz谱投影范数的渐近估计,证明系统的本征向量不能构成状态空间的基,但我们仍给出了方程的解在平衡点附近按照本征向量的的渐近展开.     

具有周期修复的机器人系统指数稳定性分析

研究具有周期修复函数的机器人与其连带的安全装置构成的系统的可靠性.运用泛函分析的方法,特别是Banach空间上的线性算子半群C_0理论,证明了系统的适定性,并通过分析系统本质谱和经过扰动后半群的本质谱半径的变化,给出解的有限展开式。并进一步证明,0是系统的严格占优本征值,系统的非零本征值至多有两个,从而表明系统解以指数形式收敛.     

可修复人机系统的指数稳定性

研究了两相同部件温储备可修的人机系统,运用C_0半群的相关理论,对系统主算子的谱界进行估值.估算系统的算子产生的半群的增长界,然后运用了共尾的概念及相关的理论,得到了系统算子A+B的谱界与系统算子产生的半群的增长界相同.进而运用相关代数知识证得,0为系统算子的简单本征值,并分析了系统算子的谱分布,得到系统的指数稳定性.并研究了系统算子预解式的特性.对任意给定的δ0,γ=a+bi,-μ+δa_1≤a≤a_2,得到lim|b|→∞‖R(γ;A+B)‖=0.进而得到在~sRγ≥a_1的右半平面内相应于系统算子A+B的谱点由有限个本征值组成.     

Timoshenko梁点反馈的稳定性

研究T im oshenko梁点反馈的稳定性.用线性算子半群方法证明了闭环系统的适定性,并应用算子谱特征得到了闭环系统的强渐近稳定性的充分必要条件.同时,给出了保守系统的几个能观性不等式.     

关于开或闭模型的指数稳定性

讨论了系统解的渐进稳定性和指数稳定性,证明了系统在Banach空间中生成正的C_0-半群以及系统算子0本征值的存在性,系统算子的谱点均为于复平面的左半平面且在虚轴上除0外无谱,并通过分析系统本质谱界经过扰动后的变化,进一步表明在一定条件下,系统的动态解以指数形式收敛于系统的稳态解.     

THE LARGE TIME CONVERGENCE OF SPECTRAL METHOD FOR GENERALIZED KURAMOTO-SIVASHINSKY EQUATION (Ⅱ)

1.IntroductionInthepaper[1],westudedthegeneralizedKuramotrySivashinskyequationWeProvedtheexistenceanduniquenessofglobalsolutionforperiodicinitialproblemandgavethelargetimeerrorestimationforthesolutionofcontinuousspectralmethod.Theaimofthispaperistostudyfullydiscretespectralmethodandthelongtimebehaviorofthesolutionofthissystem.In61wegiventhelargetimeerrorestimationforfullydiscretesolutionofspectralmethod.In52weprove-theexistenceofapproximateattractorsAN,4anding3weprovetheconvergenceofapproal…     

保持算子截断的可加映射

Let H be a complex Hilbert space and B(H)the algebra of all bounded linear operators on H.An operator A is called the truncation of B in B(H)if A=P_ABP_A^*,where PA and P_A^*denote projections onto the closures of R(A)and R(A^*),respectively.In this paper,we determine the structures of all additive surjective maps on B(H)preserving the truncation of operators in both directions.     

Stability results and existence theorems for nonlinear delay-fractional differential equations with $\varphi^*_p$-operator

The study of delay-fractional differential equations (fractional DEs) have recently attracted a lot of attention from scientists working on many different subjects dealing with mathematically modeling. In the study of fractional DEs the first question one might raise is whether the problem has a solution or not. Also, whether the problem is stable or not? In order to ensure the answer to these questions, we discuss the existence and uniqueness of solutions (EUS) and Hyers-Ulam stability (HUS) for our proposed problem, a nonlinear fractional DE with $p$-Laplacian operator and a non zero delay $\tau>0$ of order $n-1<\nu^*,\,\epsilon相似文献   

Data-sparse approximation to the operator-valued functions of elliptic operator

In previous papers the arithmetic of hierarchical matrices has been described, which allows us to compute the inverse, for instance, of finite element stiffness matrices discretising an elliptic operator The required computing time is up to logarithmic factors linear in the dimension of the matrix. In particular, this technique can be used for the computation of the discrete analogue of a resolvent

In the present paper, we consider various operator functions, the operator exponential negative fractional powers , the cosine operator function and, finally, the solution operator of the Lyapunov equation. Using the Dunford-Cauchy representation, we get integrals which can be discretised by a quadrature formula which involves the resolvents mentioned above. We give error estimates which are partly exponentially, partly polynomially decreasing.

     

Boundedness of the Cesàro Operator in Hardy Spaces

The Ces\aro operator $\mathcal{C}_{\alpha}$ is defined by \begin{equation*} (\mathcal{C}_{\alpha}f)(x) = \int_{0}^{1}t^{-1}f\left( t^{-1}x \right)\alpha (1-t)^{\alpha -1}\,dt~, \end{equation*} where $f$ denotes a function on $\mathbb{R}$. We prove that $\mathcal{C}_{\alpha}$, $\alpha >0$, is a bounded operator in the Hardy space $H^{p}$ for every $0 < p \leqq 1$.     

自伴算子空间上保持Jordan积投影的线性映射

Let Bs(H) be the real linear space of all self-adjoint operators on a complex Hilbert space H with dim H ≥ 2.It is proved that a linear surjective map on Bs (H) preserves the nonzero projections of Jordan products of two operators if and only if there is a unitary or an anti-unitary operator U on H such that (X)=λU XU,X∈Bs(H) for some constant λ with λ∈{1,1}.     

Spectral Shorted Operators

If $$\mathcal{H}$$ is a Hilbert space, $$\mathcal{S}$$ is a closed subspace of $$\mathcal{H},$$ and A is a positive bounded linear operator on $$\mathcal{H},$$ the spectral shorted operator $$\rho \left( {\mathcal{S},\mathcal{A}} \right)$$ is defined as the infimum of the sequence $$\sum (\mathcal{S},A^n )^{1/n} ,$$ where denotes $$\sum \left( {\mathcal{S},B} \right)$$ the shorted operator of B to $$\mathcal{S}.$$ We characterize the left spectral resolution of $$\rho \left( {\mathcal{S},\mathcal{A}} \right)$$ and show several properties of this operator, particularly in the case that dim $${\mathcal{S} = 1.}$$ We use these results to generalize the concept of Kolmogorov complexity for the infinite dimensional case and for non invertible operators.     

Boundedness of High Order Commutators of Riesz Transforms Associated with Schrödinger Type Operators

Let L_2=(-?)~2+ V~2 be the Schr?dinger type operator, where V■0 is a nonnegative potential and belongs to the reverse H?lder class RH_(q1) for q_1 n/2, n ≥5. The higher Riesz transform associated with L_2 is denoted by ■and its dual is denoted by ■. In this paper, we consider the m-order commutators [b~m, R] and [b~m, R*], and establish the(L~p, L~q)-boundedness of these commutators when b belongs to the new Campanato space Λ_β~θ(ρ) and 1/q = 1/p-mβ/n.     

Asymptotic Behaviour of Parabolic Problems with Delays in the Highest Order Derivatives

We use semigroup methods to investigate the partial functional differential equation $u(t)=Au(t)+ \int_{-r}^0 dB(\theta)u(t+\theta)$ for a sectorial operator $A$ on a Banach space $X$ and a function $B:[-r,0] \to\cL(D(A),X)$ of bounded variation having no mass at 0. Using a perturbation theorem due to Weiss and Staffans, we construct the solution semigroup on a product space in order to solve the delay equation in a classical sense. Employing the spectrum of the semigroup and its generator, we then study exponential dichotomy and stability of solutions. If $X$ is a Hilbert space, %C% these properties can be characterized by estimates on $(\la-A-\widehat{dB}(\la))^{-1}\in\cL(X,D(A))$. Related results on stability also hold for general Banach spaces. The case $B=\eta A$ with scalar valued $\eta$ is treated in some detail.     

Lipschitz Estimates for Commutators of $N$-Dimensional Fractional Hardy Operators

In this paper, it is proved that the commutator$\mathcal{H}_{β,b}$ which is generated by the $n$-dimensional fractional Hardy operator $\mathcal{H}_β$ and $b\in \dot{Λ}_α(\mathbb{R}^n)$ is bounded from $L^P(\mathbb{R}^n)$ to $L^q(\mathbb{R}^n)$, where $0<α<1,1相似文献