• 제목/요약/키워드: Operator inequalities

검색결과 135건 처리시간 0.026초

A GENERAL VISCOSITY APPROXIMATION METHOD OF FIXED POINT SOLUTIONS OF VARIATIONAL INEQUALITIES FOR NONEXPANSIVE SEMIGROUPS IN HILBERT SPACES

  • Plubtieng, Somyot;Wangkeeree, Rattanaporn
    • 대한수학회보
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    • 제45권4호
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    • pp.717-728
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    • 2008
  • Let H be a real Hilbert space and S = {T(s) : $0\;{\leq}\;s\;<\;{\infty}$} be a nonexpansive semigroup on H such that $F(S)\;{\neq}\;{\emptyset}$ For a contraction f with coefficient 0 < $\alpha$ < 1, a strongly positive bounded linear operator A with coefficient $\bar{\gamma}$ > 0. Let 0 < $\gamma$ < $\frac{\bar{\gamma}}{\alpha}$. It is proved that the sequences {$x_t$} and {$x_n$} generated by the iterative method $$x_t\;=\;t{\gamma}f(x_t)\;+\;(I\;-\;tA){\frac{1}{{\lambda}_t}}\;{\int_0}^{{\lambda}_t}\;T(s){x_t}ds,$$ and $$x_{n+1}\;=\;{\alpha}_n{\gamma}f(x_n)\;+\;(I\;-\;{\alpha}_nA)\frac{1}{t_n}\;{\int_0}^{t_n}\;T(s){x_n}ds,$$ where {t}, {${\alpha}_n$} $\subset$ (0, 1) and {${\lambda}_t$}, {$t_n$} are positive real divergent sequences, converges strongly to a common fixed point $\tilde{x}\;{\in}\;F(S)$ which solves the variational inequality $\langle({\gamma}f\;-\;A)\tilde{x},\;x\;-\;\tilde{x}{\rangle}\;{\leq}\;0$ for $x\;{\in}\;F(S)$.

The Fekete-Szegö Problem for a Generalized Subclass of Analytic Functions

  • Deniz, Erhan;Orhan, Halit
    • Kyungpook Mathematical Journal
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    • 제50권1호
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    • pp.37-47
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    • 2010
  • In this present work, the authors obtain Fekete-Szeg$\ddot{o}$ inequality for certain normalized analytic function f(z) defined on the open unit disk for which $\frac{(1-{\alpha})z(D^m_{{\lambda},{\mu}}f(z))'+{\alpha}z(D^{m+1}_{{\lambda},{\mu}}f(z))'}{(1-{\alpha})D^m_{{\lambda},{\mu}}f(z)+{\alpha}D^{m+1}_{{\lambda},{\mu}}f(z)}$ ${\alpha}{\geq}0$) lies in a region starlike with respect to 1 and is symmetric with respect to the real axis. Also certain applications of the main result for a class of functions defined by Hadamard product (or convolution) are given. As a special case of this result, Fekete-Szeg$\ddot{o}$ inequality for a class of functions defined through fractional derivatives is obtained. The motivation of this paper is to generalize the Fekete-Szeg$\ddot{o}$ inequalities obtained by Srivastava et al., Orhan et al. and Shanmugam et al., by making use of the generalized differential operator $D^m_{{\lambda},{\mu}}$.

단일 분산시스템의 강인안정성 해석 (Stability Robustness of Unified Decentralized Systems)

  • 이동기;허광희;오도창;이규;이우상
    • 전자공학회논문지SC
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    • 제44권2호
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    • pp.1-9
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    • 2007
  • 이 논문에서는 델타연산자를 사용하는 단일접근법에 의해 단일분산시스템에 대한 변동경계치의 새로운 결과를 제시하였다. 시스템 불확실성이 존재하는 경우에 대한 새로운 장인 안정성 경계치를 이용하여 단일 분산시스템의 강인 안정성 해석이 수행되었다. 새로운 단일 안정성 경계치는 단일 리아프노프 행렬 방정식에 근거하여 개발되었다. 또한 새로운 단일 경계치가 적용되었을 때 시스템이 그 안정성을 유지함을 나타내었고 예제가 이 제안된 결과를 입증하기 위해 제시되었다.

A Novel Stabilizing Control for Neural Nonlinear Systems with Time Delays by State and Dynamic Output Feedback

  • Liu, Mei-Qin;Wang, Hui-Fang
    • International Journal of Control, Automation, and Systems
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    • 제6권1호
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    • pp.24-34
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    • 2008
  • A novel neural network model, termed the standard neural network model (SNNM), similar to the nominal model in linear robust control theory, is suggested to facilitate the synthesis of controllers for delayed (or non-delayed) nonlinear systems composed of neural networks. The model is composed of a linear dynamic system and a bounded static delayed (or non-delayed) nonlinear operator. Based on the global asymptotic stability analysis of SNNMs, Static state-feedback controller and dynamic output feedback controller are designed for the SNNMs to stabilize the closed-loop systems, respectively. The control design equations are shown to be a set of linear matrix inequalities (LMIs) which can be easily solved by various convex optimization algorithms to determine the control signals. Most neural-network-based nonlinear systems with time delays or without time delays can be transformed into the SNNMs for controller synthesis in a unified way. Two application examples are given where the SNNMs are employed to synthesize the feedback stabilizing controllers for an SISO nonlinear system modeled by the neural network, and for a chaotic neural network, respectively. Through these examples, it is demonstrated that the SNNM not only makes controller synthesis of neural-network-based systems much easier, but also provides a new approach to the synthesis of the controllers for the other type of nonlinear systems.

ALTERNATED INERTIAL RELAXED TSENG METHOD FOR SOLVING FIXED POINT AND QUASI-MONOTONE VARIATIONAL INEQUALITY PROBLEMS

  • A. E. Ofem;A. A. Mebawondu;C. Agbonkhese;G. C. Ugwunnadi;O. K. Narain
    • Nonlinear Functional Analysis and Applications
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    • 제29권1호
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    • pp.131-164
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    • 2024
  • In this research, we study a modified relaxed Tseng method with a single projection approach for solving common solution to a fixed point problem involving finite family of τ-demimetric operators and a quasi-monotone variational inequalities in real Hilbert spaces with alternating inertial extrapolation steps and adaptive non-monotonic step sizes. Under some appropriate conditions that are imposed on the parameters, the weak and linear convergence results of the proposed iterative scheme are established. Furthermore, we present some numerical examples and application of our proposed methods in comparison with other existing iterative methods. In order to show the practical applicability of our method to real word problems, we show that our algorithm has better restoration efficiency than many well known methods in image restoration problem. Our proposed iterative method generalizes and extends many existing methods in the literature.