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Control Theory and Technology 2020年第2期18卷 168-181页

作者： Zhongda LU Junxiao LU Jiaqi ZHANG fengxia xu College of Mechanical and Electrical Engineering Qiqihar UniversityQiqihar Heilongjiang 161006China ZCollege of Computer and Control Engineering Qiqihar UniversityQiqihar Heilongjiang 161006China

This paper is aimed at investigating the problem of mixed time/event-triggered finite-time non-fragile filtering for nonlinear networked control systems with ***,a fuzzy nonlinear networked control system model is established by interval type-2(IT2)Takagi-Sugeno(T-S)fuzzy model,the designed non-fragile filter resolves the filter parameter uncertainties and uses different membership functions from the IT2 T-S fuzzy ***,a novel mixed time/event-triggered transmission mechanism is proposed,which decreases the waste of network ***,Bernoulli random variables are used to describe the cases of random switching mixed time/event-triggered transmission ***,the error filtering system is designed by considering a Lyapunov function and a sufficient condition of finite-time *** addition,the existence conditions for the finite-time non-fragile filter are given by the linear matrix inequalities(LMIs).Finally,two simulation results are presented to prove the effectiveness of the obtained method.

关键词： Interval type-2 Takagi-Sugeno fuzzy model networked control systems mixed time/event-triggered transmission mechanism finite-time non-fragile filter

Improvement of precision for pendulous integrating gyro accelerometer via adaptive internal model control

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Journal of Systems Engineering and Electronics 2007年第4期18卷 841-845页

作者： xu fengxia Xia Gang Zeng Ming Sun Baoku Zhao xuezeng Harbin Institute of Technology Harbin 150001 P. R. China The Inst.13 Aerospace Time Electronics Corporation Beijing 100854 P. R. China

An adaptive internal mode control is proposed to eliminate effectively periodic disturbance with uncertain frequency caused by input error angle of PIGA （Pendulous Integrating Gyro Accelerometer）. An adaptive algorithm with periodic disturbance frequency identification on line is applied and the internal model controller parameters are adjusted to eliminate disturbance. Then the convergence of this algorithm and the stability of the system are proved by the averaging method. Simulation results verify the proposed scheme can eliminate periodic disturbance and improve the test precision for PIGA effectively.

关键词： PIGA periodic disturbance adaptive algorithm internal model control

An improved trust region method for unconstrained optimization

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Science China Mathematics 2013年第2期56卷 425-434页

作者： ZHOU QingHua ZHANG YaRui xu fengxia GENG Yan SUN XiaoDian College of Mathematics and Computer Science Hebei University State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology School of Life Sciences and Institutes of Biomedical SciencesFudan University

In this paper,we propose an improved trust region method for solving unconstrained optimization *** with traditional trust region methods,our algorithm does not resolve the subproblem within the trust region centered at the current iteration point,but within an improved one centered at some point located in the direction of the negative gradient,while the current iteration point is on the boundary *** prove the global convergence properties of the new improved trust region algorithm and give the computational results which demonstrate the effectiveness of our algorithm.

关键词： unconstrained optimization trust region methods global convergence negative gradient direction iterative

Floral ontogeny and anatomy of staminate flowers of Myristicaceae

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Floral ontogeny and anatomy of staminate flowers of Myristic...

生态文明建设中的植物学：现在与未来——中国植物学会第十五届会员代表大会暨八十周年学术年会

作者： YANG GuiFang xu fengxia Key Laboratory of Plant Resources Conservation and Sustainable Utilization South China Botanical Garden University of Chinese Academy of Sciences

Myristicaceae is distinctive in having dioecious, unisexual flowers with stamens fused into a synandrium, which consists of a single whorl of sessile anthers borne around a sterile central column. The peculiar androecial features with the greatest variation have played an essential role in the definition of genera and represent key characters for their identification. To depict the androecium diversity and better understanding the origin and evolution of synandria in Myristicaceae, floral ontogeny and anatomy of staminate flowers of several development phases in Horsfieldia and Myristica were investigated respectively, using scanning electron microscopy and light microscopy. In Myristica, depending on the availability of the space of floral apex, nine or ten anther primordia are initiated on the margins of a broadened floral apex, with a somewhat three-sided shape, in an irregular development pattern. Namely, three or four anther primordia arise quickly in succession (or almost simultaneously) on one side of the floral apex, which made the earliest initiated anther primordium the largest. Then subsequently, another group of three or four anther primordia are initiated on the second side of the floral apex in the same development pattern as the first group of anther primordia, and finally so do the third set of anther primordia initiating on the third side of the floral apex, resulting that the three anther primordia on the corner of floral apex are great larger than the rest of anther primordia. Although with less anther primordia and various shapes of floral apex, in Horsfieldia, four to six anther primordia are also initiated in irregular development pattern, which they have a tendency to arise on one side of the floral apex, then by the second side, and finally the third, with development interval within sides of floral apex. Moreover, the dehiscence of thecae and releasing of microspores of Horsfieldia also exhibit a similar development pattern as the anther pri

关键词： Myristicaceae Unisexual Synandrium Irregular development pattern

Morphology and structure of Annonaceous stamens and their systematic implications

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Morphology and structure of Annonaceous stamens and their sy...

第十届全国植物结构与生殖生物学学术研讨会

作者： fengxia xu Qian Li South China Botanical Garden

The comparative morphology of stamens (25 genera 42 species 1 variety)and structure of anthers(14 genera 21 species 1 variety) and floral morphogenesis of Saccopetalum prolificum and Annona muricata were observed by scanning electron microscope (SEM)、traditional paraffin sections and *** pollen sac wall comprises an epidemis、an endothecium and a vaiable number of middle *** epidemis is usually one layer thick and *** endothecium is also one layer thick (sometimes2 or3 layers) and elongates radially and thickened (zonal,puncate or reticulate).The endothecium are subjacent to the pollen sac and enclose part of the pollen sac *** area between the individual pollen sacs is usually not thickened and it breakes up firstly when the anther *** hypodermis exists only in Pseuduvaria and Mitrephora and is one layer thick,unthickened and contact the endothecium to enclose the whole *** anther has 1vascular bundles and its dehiscence direction is diverse (latrorse,ditrorse,introrse,and outrorse).The genera exiamined can be recognized by morphology of stamens,connective apex and epidemis of connective *** to our research,Uvaria is primitive in its morphology of stamen and anther structure characters (filament short;fertile area small;dehiscecce in latrorse and ditrorse direction).Annona is thought to be evolutive because its anther dehiscecce in an extrorse and introrse direction and long filament.

关键词： Annonaceae stamen morphology structure systematic implications

An Improved Event-triggered H∞ Filtering for Nonlinear Systems

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An Improved Event-triggered H∞ Filtering for Nonlinear Syst...

第30届中国控制与决策会议

作者： Zhongda Lu Guangtao Ran Fengbin Zhang fengxia xu School of Computer and Control Engineering Qiqihar University College of Computer Science and Technology Harbin University of Science and Technology

This paper addresses event-triggered ∞H filtering for nonlinear Networked Control Systems with time-delay. A new event-triggered scheme is proposed to determine the state transmission only when satisfying trigger conditions. Considering the effects of the event-triggered scheme and network-induced, the fuzzy filtering error system is built based on T-S fuzzy model. An augmented Lyapunov function is constructed with integral items, and the Writinger inequality is first utilized to analysis and design ∞H filtering error system to derived a less conservative stability criterion. An illustrative example is presented to demonstrate the merit of the proposed event-triggered scheme and the effectiveness of the proposed method.

关键词： Event-triggered ∞H filtering Networked Control Systems Writinger inequality

The Fuzzy PID Controller Design Base On Nonlinear U-model

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The Fuzzy PID Controller Design Base On Nonlinear U-model

第30届中国控制与决策会议

作者： fengxia xu Zhilong Wang Xiaohui Song Shanshan Wang Computer and Control Engineering Collage Qiqihar University

Nonlinear modeling is studied in this paper, the Nonlinear model is set by time varying polynomial and the ShengJin formula is introduced to solve the roots of Newton-Raphson, then change the Nonlinear model to the U-model. Base on the typical the PID controller, the currency U-model Fuzzy PID system is designed with the Fuzzy algorithm and the structure of U-model. The new controller keeps the generality of PID controller and enhances the accuracy of nonlinear system,it is theory support that the nonlinear system control can be solved.

关键词： U-model Shengjin Formula iterative algorithm Fuzzy control

基于多周期有限维重复控制的转台动不平衡扰动抑制

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机械工程学报 2006年第8期42卷 40-43页

作者：徐凤霞曾鸣苏宝库哈尔滨工业大学控制科学与工程系哈尔滨150001

通过建立三轴转台的动不平衡模型,得出转台存在多周期扰动力矩。该多周期扰动力矩与转台三轴转速有关,影响转台的定位精度、位置精度和速率精度。为抑制三轴转台系统的扰动力矩,提出多周期有限维重复控制方法,并证明该方法能消除多周期... 详细信息

通过建立三轴转台的动不平衡模型,得出转台存在多周期扰动力矩。该多周期扰动力矩与转台三轴转速有关,影响转台的定位精度、位置精度和速率精度。为抑制三轴转台系统的扰动力矩,提出多周期有限维重复控制方法,并证明该方法能消除多周期扰动引起的转台系统误差。仿真结果表明多周期有限维重复控制可以有效地抑制转台系统存在的动不平衡扰动。

关键词：三轴转台动不平衡多周期扰动有限维重复控制

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几种含笑属(木兰科)植物的花粉形态

武汉植物学研究 1999年第4期17卷 303-306页

作者：徐凤霞中国科学院华南植物研究所广州510650

含笑属 ( Michelia) 4种花粉光镜下形态相似。SEM下观察 ,黄兰 ( ***)和金叶含笑 ( ***)表面雕纹为小穿孔 ,苦梓含笑 ( ***)为小穴 ,野含笑 ( ***-iana)为细皱纹 ,较粗糙。 TEM下观察 ,4种花粉外壁均可分为覆盖层、柱状层和基层。其中... 详细信息

含笑属 ( Michelia) 4种花粉光镜下形态相似。SEM下观察 ,黄兰 ( ***)和金叶含笑 ( ***)表面雕纹为小穿孔 ,苦梓含笑 ( ***)为小穴 ,野含笑 ( ***-iana)为细皱纹 ,较粗糙。 TEM下观察 ,4种花粉外壁均可分为覆盖层、柱状层和基层。其中黄兰的柱状层结构较原始 ,金叶含笑的较进化。花粉形态在一定程度上可反映类群的系统演化。

关键词：含笑属花粉形态系统演化木兰科

Multidimensional attention and multiscale upsampling for semantic segmentation

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Journal of Measurement Science and Instrumentation 2022年第1期13卷 68-78页

作者： LU Zhongda ZHANG Chunda WANG Lijing xu fengxia School of Mechanical and Electrical Engineering Qiqihar University Qiqihar 161000 China Heilongjiang Province Collaborative Innovation Center for Intelligent Manufacturing Equipment Industrialization Qiqihar 161000 China

Semantic segmentation is for pixel-level classification tasks,and contextual information has an important impact on the performance of *** order to capture richer contextual information,we adopt ResNet as the backbone network and designs an encoder-decoder architecture based on multidimensional attention(MDA)module and multiscale upsampling(MSU)*** MDA module calculates the attention matrices of the three dimensions to capture the dependency of each position,and adaptively captures the image *** MSU module adopts parallel branches to capture the multiscale features of the images,and multiscale feature aggregation can enhance contextual information.A series of experiments demonstrate the validity of the model on Cityscapes and Camvid datasets.

关键词： semantic segmentation attention mechanism multiscale feature convolutional neural network(CNN) residual network(ResNet)