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Fixed-time attitude tracking control for spacecraft based on a fixed-time extended state observer

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Science China(Information Sciences) 2021年第11期64卷 154-170页

作者： Lijun ZHANG Yuanqing xia Ganghui SHEN Bing cui School of Automation Beijing Institute of Technology

This paper deals with the problem of fixed-time attitude tracking control for spacecraft subject to model uncertainties and external disturbances. Firstly, by using a fixed-time extended state observer(Fx TESO), the synthetic uncertainties generated by external disturbances and model deviations can be estimated and compensated accordingly. We propose a novel Fx TESO aimed to improve previous *** with the existing extended state observer(ESO), the proposed Fx TESO provides faster convergence and higher accuracy. Then, we design a fixed-time adaptive attitude tracking controller based on the strategy combining the Fx TESO and fast non-singular terminal sliding mode control(FNTSMC), such that a desired attitude can be achieved accurately, which does not only allow providing fast and accurate responses,and acceptable chattering suppression, but also avoid singularity. Finally, the numerical simulation results are discussed to verify the efficiency and merits of the proposed control strategy.

关键词： spacecraft fixed time attitude tracking FxTESO FNTSMC

On arithmetic properties of Cantor sets

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Science China mathematics 2022年第10期65卷 2035-2060页

作者： Lu cui Minghui ma Academy of mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

In this paper,we study three types of Cantor *** any integer m≥4,we show that every real number in[0,k]is the sum of at most k m-th powers of elements in the Cantor ternary set C for some positive integer k,and the smallest such k is 2~***,we generalize this result to the middle-1/αCantor set for1mage W of the Cantor dust C×C into the complex plane C,we prove that for any integer m≥3,every element in the closed unit disk in C can be written as the sum of at most 2^(m+8)m-th powers of elements in *** last,some similar results on p-adic Cantor sets are also obtained.

关键词： Cantor ternary set Cantor dust p-adic Cantor set Waring's problem

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无人机海上舰船目标影像超分辨率重建

现代电子技术 2025年第1期48卷 17-22页

作者：孙炜玮崔亚奇张少卿夏沭涛海军航空大学山东烟台264000 中国航空工业沈阳飞机设计研究所辽宁沈阳110035 西北工业大学陕西西安710072

针对无人机在获取海上舰船目标影像时面临的实时性与清晰度之间的矛盾,提出一种影像压缩模糊重建方法。该方法利用改进的YOLOv8检测模型和Real-ESRGAN网络,通过数据集构建、网络训练调试和部署运用等步骤,实现了在有限带宽和计算资源环... 详细信息

针对无人机在获取海上舰船目标影像时面临的实时性与清晰度之间的矛盾,提出一种影像压缩模糊重建方法。该方法利用改进的YOLOv8检测模型和Real-ESRGAN网络,通过数据集构建、网络训练调试和部署运用等步骤,实现了在有限带宽和计算资源环境下地面端高质量舰船目标影像的实时重建。首先利用改进的YOLOv8模型对影像中舰船目标进行精准检测和定位,随后通过Real-ESRGAN网络对压缩及模糊影像进行重建,以恢复影像的高分辨率和细节信息。实验结果表明,该方法不仅显著提升了影像的清晰度和检测准确性,还大幅减少了带宽消耗,满足了无人机舰船识别的高实时性要求,且在资源受限的情况下表现尤为突出。为无人机在海上舰船目标监测领域提供了一种有效的解决方案,不仅提高了无人机的监测和识别能力,也为进一步推进无人机在海洋监测中的广泛应用奠定了基础。

关键词：无人机影像海面舰船双向特征融合模型 Real-ESRGAN网络改进的YOLOv8检测模型海上舰船目标监测

露天矿区环境下GPS/INS组合导航算法研究

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大地测量与地球动力学 2025年第1期45卷 29-35页

作者：郝婷崔丽珍杜永兴马宝良内蒙古科技大学数智产业学院内蒙古自治区包头市014010

针对露天矿区道路窄、弯道多,沿途布满碎石、路面颠簸不平,导致运输车辆在定位时出现系统模型异常及量测噪声不确定性的问题,提出一种带有噪声估计器的SVD-AUKF算法。该算法通过对协方差矩阵进行奇异值分解,抑制滤波过程中出现的病态矩... 详细信息

针对露天矿区道路窄、弯道多,沿途布满碎石、路面颠簸不平,导致运输车辆在定位时出现系统模型异常及量测噪声不确定性的问题,提出一种带有噪声估计器的SVD-AUKF算法。该算法通过对协方差矩阵进行奇异值分解,抑制滤波过程中出现的病态矩阵,利用Sage-Husa估计器对量测噪声进行估计,减少系统状态误差,引入自适应因子实时修正系统模型误差以抑制滤波发散。将提出的SVD-AUKF算法应用于GPS/INS组合导航系统模型,并在矿山环境下进行车载实验,结果表明,新算法适用性好,相较AUKF算法,每个定位点在东、北、天方向上的位置精度分别提高50.69%、51.20%、48.54%,速度精度分别提高31.24%、33.83%、31.30%,能够有效改善滤波性能,提高系统定位精度。

关键词：无迹卡尔曼滤波 Sage-Husa估计器 SVD-AUKF 松组合露天矿区

A new method for modeling thermo-mechanical behaviors of polycrystalline aggregates

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Science China(Physics,Mechanics & Astronomy) 2012年第11期55卷 2143-2151页

作者： TIAN xia cui JunZhi LI BoWen College of Mechanics and materials HoHai UniversityNanjing 210098China LSEC ICMSECAcademy of Mathematics and System SciencesChinese Academy of SciencesBeijing 100190China

We present in this paper a numerical algorithm that couples the atomistic and continuum models for the thermal-mechanical coupled problem of polycrystalline *** key point is that the conservation laws should be satisfied for both the atomistic and continuum models at the *** with the traditional methods which construct the constitutive equations of the grain interiors and grain boundaries by continuum mechanics,our model calculates the continuum fluxes through molecular dynamics simulations,provided that the atomistic simulations are consistent with the local microstate of the *** the grain interiors without defects,central schemes are available for solving the conservation laws and the constitutive parameters can be obtained via molecular dynamics *** the grain boundary structures,the front tracking method is employed because the solutions of the conservation equations are discontinuous near the ***,appropriate control volumes are chosen at both sides of the interface,then the finite volume method is applied to solve the continuum equations in each control *** near both sides of the interface are calculated via atomistic ***,all thermo-mechanical information can be obtained.

关键词： polycrystalline aggregates molecular dynamics simulation continuum model thermo-mechanical coupled

Error quantification of the normalized right graph symbol for an errors-in-variables system

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Control Theory and Technology 2015年第3期13卷 238-244页

作者： Lihui GENG Shigang cui Zeyu xia Tianjin Key Laboratory of Information Sensing and Intelligent Control School of Automation and Electrical EngineeringTianjin University of Technology and Education

This paper proposes a novel method to quantify the error of a nominal normalized right graph symbol （NRGS） for an errors- in-variables （EIV） system corrupted with bounded noise. Following an identification framework for estimation of a perturbation model set, a worst-case v-gap error bound for the estimated nominal NRGS can be first determined from a priori and a posteriori information on the underlying EIV system. Then, an NRGS perturbation model set can be derived from a close relation between the v-gap metric of two models and H∞-norm of their NRGSs＇ difference. The obtained NRGS perturbation model set paves the way for robust controller design using an H∞ loop-shaping method because it is a standard form of the well-known NCF （normalized coprime factor） perturbation model set. Finally, a numerical simulation is used to demonstrate the effectiveness of the proposed identification method.

关键词： Error quantification errors-in-variables normalized right graph symbol

Identification and Estimation of Generalized Additive Partial Linear Models with Nonignorable Missing Response

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Communications in mathematics and Statistics 2024年第1期12卷 113-156页

作者： Jierui Du Yuan Li xia cui School of Economics and Statistics Guangzhou University510006 GuangzhouPeople’s Republic of China

The generalized additive partial linear models(GAPLM)have been widely used for flexiblemodeling of various types of *** practice,missing data usually occurs in studies of economics,medicine,and public *** address the problem of identifying and estimating GAPLM when the response variable is nonignorably *** types of monotone missing data mechanism are assumed,including logistic model,probit model and complementary log-log *** this situation,likelihood based on observed data may not be *** this article,we show that the parameters of interest are identifiable under very mild conditions,and then construct the estimators of the unknown parameters and unknown functions based on a likelihood-based approach by expanding the unknown functions as a linear combination of polynomial spline *** establish asymptotic normality for the estimators of the parametric *** studies demonstrate that the proposed inference procedure performs well in many *** apply the proposed method to the household income dataset from the Chinese Household Income Project Survey 2013.

关键词： Generalized additive partial linear models Nonignorable missingness Identifiability Observed likelihood

ELASTIC DYNAMIC ANALYSIS OF MODERATELY THICK PLATE USING MESHLESS LRPIM

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Acta Mechanica Solida Sinica 2009年第2期22卷 116-124页

作者： Ping xia Shuyao Long Hongxue cui State Key Laboratory of Advanced Design and manufacture for Vehicle Body Hunan University Changsha 410082 China College of Mechanics and Aerospace Engineering Hunan University Changsha 410082 China Department of Mechanical Engineering Hunan Institute of Engineering Xiangtan 411101 China

A meshless local radial point interpolation method （LRPIM） for solving elastic dy-namic problems of moderately thick plates is presented in this paper. The discretized system equation of the plate is obtained using a locally weighted residual method. It uses a radial basis function （RBF） coupled with a polynomial basis function as a trial function,and uses the quartic spline function as a test function of the weighted residual method. The shape function has the properties of the Kronecker delta function,and no additional treatment is done to impose essen-tial boundary conditions. The Newmark method for solving the dynamic problem is adopted in computation. Effects of sizes of the quadrature sub-domain and influence domain on the dynamic properties are investigated. The numerical results show that the presented method can give quite accurate results for the elastic dynamic problem of the moderately thick plate.

关键词： meshless method moderately thick plate local radial point interpolation method,dynamic analysis Newmark method

Mesoporous cobalt oxide for largely improved lithium storage properties

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Chinese Chemical Letters 2012年第8期23卷 949-952页

作者： mai xia ma Faculty of Chemistry and material Science Langfang Teachers CollegeLangfang 065000China

We report the microstructure, application for lithium-ion batteries of mesoporous Co304 prepared by modified KIT-6 template method. The sample was characterized by XRD, TEM, HRTEM and nitrogen adsorption. Their electrochemical behaviors as electrode reactants for lithium ion batteries were evaluated by cyclic voltammograms and static charge-discharge. A direct comparison of electrochemical behaviors between mesoporous nanostructure and bulk reflects interesting ＂nanostructure effect＂, which is reasonably discussed in terms of how the 3D nanostructures of Co3O4 materials function in tuning their electrochemistry. The results demonstrate that further improvement of electrochemical performance in transition metal-oxide-based anode materials can be realized via the design of multiporous nanostructured materials.

关键词： Mesoporous Co3O4 High lithium storage capacity Nanostructure effect