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Frontiers of Mathematics in China 2022年第1期17卷 47-77页

作者： genqi xu School of Mathematical Sciences Tianjin UniversityTianjin 300350China

This paper is a survey for development of linear distributed parameter *** first we point out some questions existing in current study of control theory for the L^(p)linear system with an unbounded control operator and an unbounded observation operator,such as stabilization problem and observer theory that are closely relevant to state feedback *** then we survey briefly some results on relevant problems that are related to solvability of linear differential equations in general Banach space and semigroup *** a principle,we propose a concept of admissible state feedback operator for system(A,B).Finally we give an existence result of admissible state feedback operators,including semigroup generation and the equivalent conditions of admissibility of state feedback operators,for an L^(p)well-posed system.

关键词： Linear differential equation semigroup perturbation Lp well-posed system admissible state feedback operator

Stabilization of an Euler-Bernoulli Beam with a Tip Mass Under the Unknown Boundary External Disturbances

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Journal of Systems Science & Complexity 2017年第4期30卷 803-817页

作者： LI Yanfang xu genqi Department of Mathematics Tianjin UniversityTianjin 300350China

This paper studies the stabilization problem of an Euler-Bernoulli beam with a tip mass,which undergoes unknown but uniform bounded disturbance at tip mass. Here the nonlinear feedback control law is used to cancel the effects of the external disturbances. For the controlled nonlinear system,the authors prove the well-posedness by the maximal monotone operator theory and the variational principle. Further the authors prove that the controlled nonlinear system is exponential stable by constructing a suitable Lyapunov function. Finally, some numerical simulations are given to support these results.

关键词： Euler-Bernoulli beam equation exponential stabilization monotone operators nonlinear feedback control.

ASYMPTOTIC STABILITY AND RIESZ BASIS PROPERTY FOR TREE-SHAPED NETWORK OF STRINGS

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Journal of Systems Science & Complexity 2011年第2期24卷 225-252页

作者： YanniGUO genqi xu College of Science Civil Aviation University of China Tianjin 300300 China Department of Mathematics Tianjin University Tianjin 300072 China

This paper discusses the asymptotic stability and Riesz basis generation for a general tree-shaped network of vibrating strings. All exterior vertices are assumed to be fixed and interior vertices are imposed linear damping feedbacks. This paper shows that the system is well-posed and asymptotically stable by C0-semigroup theory. With some additional conditions, the spectrum of the system is shown to be located in a strip that is parallel to the imaginary axis and the set of all generalized eigenfunctions is completed in the state space. These lead to the conclusion that there is a sequence of generalized eigenfunctions of the system, which forms a Riesz basis with parenthesis for the state space.

关键词： Completeness network of strings riesz basis with parentheses stability.

A PINNED NETWORK OF EULER-BERNOULLI BEAMS UNDER FEEDBACK CONTROLS

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Journal of Systems Science & Complexity 2013年第3期26卷 313-334页

作者： ZHANG Kuiting xu genqi Department of Mathematics Tianjin University

In this paper, the authors design boundary feedback controllers at the interior node to stabilize a star-shaped network of Euler-Bernoulli beams. The beams are pinned each other, that is, the displacements of the structure are continuous but the rotations of the beams are not continuous. The weil-posed-ness of the closed loop system is proved by the semigroup theory. The authors show that the system is asymptotically stable if the authors impose a bending moment control on each edge. Finally, the authors derive the exponential stability of the system.

关键词： Euler-Bernoulli beams pinned network semigroup theory stability.

Optimal production lot size with process deterioration under an extended inspection policy

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Journal of Systems Engineering and Electronics 2009年第4期20卷 768-776页

作者： Hu Fei xu genqi Ma Lixia Dept. of Mathematics Tianjin Univ. Tianjin 300072 P. R. China

A mathematical model to determine the optimal production lot size for a deteriorating production system under an extended product inspection policy is developed. The last-K product inspection policy is considered so that the nonconforming items can be reduced, under which the last K products in a production lot are inspected and the nonconforming items from those inspected are reworked. Consider that the products produced towards the end of a production lot are more likely to be nonconforming, is proposed an extended product inspection policy for a deteriorating production system. That is, in a production lot, product inspections are performed among the middle K1 items and after inspections, all of the last K2 products are directly reworked without inspections. Our objective here is the joint optimization of the production lot size and the corresponding extended inspection policy such that the expected total cost per unit time is minimized. Since there is no closed form expression for our optimal policy, the existence for the optimal production inspection policy and an upper bound for the optimal lot size are obtained. Furthermore, an efficient solution procedure is provided to search for the optimal policy. Finally, numerical examples are given to illustrate the proposed model and indicate that the expected total cost per unit time of our product inspection model is less than that of the last-K inspection policy.

关键词： production lot size product inspection policy deteriorating production system economic manufacturing quantity.

Stability analysis of the Euler-Bernoulli beam with multi-delay controller

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Control Theory and Technology 2022年第3期20卷 338-348页

作者： Alireza Jalili Rahmtati genqi xu Sohrab Effati Department of Mathematical Sciences Sharif University of TechnologyAzadi Ave.TehranIran Department of Mathematics Tianjin UniversityNankai DistrictTianjin300072China Department of Applied Mathematics Ferdowsi University of MashhadAzadi SquareMashhadIran

In this paper,we investigate the stabilization of an Euler-Bernoulli beam with time delays in the boundary *** boundary velocity feedback law is applied to obtain the closed-loop *** is shown that this system generates a C_(0-)semigroup of linear ***,the stability of the closed-loop system is discussed for different values of the controller constants and time delays via using spectral analysis and a suitable Lyapunov function.

关键词： Euler-Bernoulli beam Time delay Lyapunov method Spectral analysis

基于AFSPSO-ν-SVM的山洪灾害预测方法研究

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计算机与现代化 2024年第5期 33-37,45页

作者：曹宁徐根祺张雯许又文何盼情刘浩西安交通工程学院土木工程学院陕西西安710300 西安交通工程学院机械与电气工程学院陕西西安710300 陕西省外经贸建设集团有限公司陕西西安710003 不详

随着科学技术的发展,人类在山区的工程活动越来越频繁,这加剧了山洪灾害的发生频率。准确及时预测出山洪灾害发生的可能性,对于保证工程安全、降低经济损失、提高人员安全防范能力具有重要意义。将人工智能算法应用于山洪灾害预测成为... 详细信息

随着科学技术的发展,人类在山区的工程活动越来越频繁,这加剧了山洪灾害的发生频率。准确及时预测出山洪灾害发生的可能性,对于保证工程安全、降低经济损失、提高人员安全防范能力具有重要意义。将人工智能算法应用于山洪灾害预测成为当下研究者们关注的焦点。为了解决当下山洪诱发因素敏感性差异导致的预测精度不足、小样本数据引起的模型拟合效果欠优以及非线性模型参数不易确定等问题,将主成分分析与ν支持向量机相结合对山洪发生进行预测,通过人工鱼群算法扩大粒子群算法中粒子的搜索范围和速度,并利用改进粒子群算法对支持向量机参数进行寻优,建立AFSPSO-ν-SVM山洪灾害概率预测模型。通过实验对比了本文模型与BL模型、ν-SVM模型、PSO-ν-SVM模型的性能,结果表明,本文模型误差最小且速度最快。本文研究为山洪预报预警领域研究提供了一种新的思路。

关键词：人工鱼群算法粒子群算法支持向量机山洪灾害预测模型

基于DEFA-LSSAR的水利工程边坡力学参数预测模型

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计算机与现代化 2024年第7期 106-111页

作者：曹宁严心娥徐根祺许又文张正勃杜倩云西安交通工程学院土木工程学院陕西西安710300 西安交通工程学院机械与电气工程学院陕西西安710300

为了解决现有水利工程边坡力学参数预测模型准确率偏低的问题,利用最小二乘支持向量机LSSAR对水利工程边坡力学参数(弹性模量E)进行预测,结合改进的萤火虫算法对模型进行优化,提出一种基于DEFA-LSSAR的水利工程边坡力学参数预测模型。... 详细信息

为了解决现有水利工程边坡力学参数预测模型准确率偏低的问题,利用最小二乘支持向量机LSSAR对水利工程边坡力学参数(弹性模量E)进行预测,结合改进的萤火虫算法对模型进行优化,提出一种基于DEFA-LSSAR的水利工程边坡力学参数预测模型。将本文所提模型分别与樽海鞘群算法、果蝇算法和哈里斯鹰优化算法优化的LSSAR模型进行对比。分析结果表明,所提出的模型预测准确率最高,达94%以上,且具有最小的适应度值,验证了所提模型的有效性和正确性。

关键词：水利工程边坡稳定性最小二乘支持向量机萤火虫算法参数预测

The Orientation Control Of The Tree-Shaped Strings Network

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The Orientation Control Of The Tree-Shaped Strings Network

Stabilisation for a wave equation with distributed time delay in the internal input

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作者： Yaru Xie genqi xu Department of Mathematics Tianjin University

ISBN: (纸本)9781538629185

In the present paper, we study the orientation control of tree-shaped strings network by the approach feedforward control. First, we design a new controller through the dynamics condition of objective network to stabilize the boundary node a1,a2, a3 and have no effect the other part of network. Furthermore, the convergence of network system continue to be discussed under some control strategy when one of the dynamics condition of the boundary w(1, t) is unknown and the original network is still proved to converge to the network of target structure. The method here is appropriate for more complex graph and mathematical model.

关键词： Orientation control Anti-disturbance Convergence of network Lyapunov method

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Stabilisation for a wave equation with distributed time dela...