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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

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

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：欧拉-伯努利梁外部扰动质量稳定性非线性系统李雅普诺夫函数反馈控制律边界

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

这份报纸讨论 asymptotic 稳定性和 Riesz 基础产生因为颤动的一个一般塑造树的网络串。所有外面的顶点被假定被修理，内部顶点被强加线性抑制反馈。这份报纸证明系统由 C 0-semigroup 理论提出得好、 asymptotically 稳定。与一些另外... 详细信息

这份报纸讨论 asymptotic 稳定性和 Riesz 基础产生因为颤动的一个一般塑造树的网络串。所有外面的顶点被假定被修理，内部顶点被强加线性抑制反馈。这份报纸证明系统由 C 0-semigroup 理论提出得好、 asymptotically 稳定。与一些另外的条件，系统的光谱被显示位于与想象的轴平行的脱衣，所有概括特徵函数的集合在州的空间被完成。这些导致有系统的概括特徵函数的一个序列的结论，它与括号形成一个 Riesz 基础州的空格。

关键词： Riesz基渐近稳定性树形网络字符串物业状态空间广义特征线性阻尼

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 are pinned each other,that is,the displacements of the structure are continuous but the rotations of the beams are not *** well-posed-ness of the closed loop system is proved by the semigroup *** authors show that the system is asymptotically stable if the authors impose a bending moment control on each ***,the authors derive the exponential stability of the system.

关键词：反馈控制器伯努利固定网络欧拉梁闭环系统稳定性星型网络

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.

三边树形一维Euler-Bernoulli梁网络的L^(2)-适定性和正则性

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系统科学与数学 2022年第12期42卷 3173-3188页

作者：祁琪刘东毅许跟起天津大学数学学院天津300350

文章考虑了由三根Euler-Bernoulli梁构成的一维网络系统.通过构造适当的乘子,文章证明了开环网络系统是L^(2)-适定的.根据输入-输出传递函数的渐近分析估计,验证了开环系统的正则性.最后,进一步讨论了其他边界条件.

关键词： Euler-Bernoulli梁开环系统 L^(2)-适定性正则性树形网络

THE WELL-POSEDNESS OF THE ABSTRACT KINETIC EQUATION BOUNDARY VALUE PROBLEMS

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Acta Mathematica Scientia 1993年第3期13卷 323-334页

作者：许跟起 Dept. of Math. Shanxi Univ. Taiyuan 030006 China

In this paper the abstract boundary value problem on Hilbert space H is studied: [GRAPHICS] where Q(+)/Q(-) are the maximum positive/negative spectral projections of self-adjoint operator T. Under suitable conditions, it is shown what the boundary value problem of abstract kinetic equation ia well-posed and can be applied to transport theory.

关键词：边值问题抽象动力方程适应性