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Adaptive Optimal Output Regulation of Interconnected Singularly Perturbed Systems With Application to Power Systems
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作者 Jianguo Zhao chunyu yang +2 位作者 Weinan Gao Linna Zhou Xiaomin Liu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期595-607,共13页
This article studies the adaptive optimal output regulation problem for a class of interconnected singularly perturbed systems(SPSs) with unknown dynamics based on reinforcement learning(RL).Taking into account the sl... This article studies the adaptive optimal output regulation problem for a class of interconnected singularly perturbed systems(SPSs) with unknown dynamics based on reinforcement learning(RL).Taking into account the slow and fast characteristics among system states,the interconnected SPS is decomposed into the slow time-scale dynamics and the fast timescale dynamics through singular perturbation theory.For the fast time-scale dynamics with interconnections,we devise a decentralized optimal control strategy by selecting appropriate weight matrices in the cost function.For the slow time-scale dynamics with unknown system parameters,an off-policy RL algorithm with convergence guarantee is given to learn the optimal control strategy in terms of measurement data.By combining the slow and fast controllers,we establish the composite decentralized adaptive optimal output regulator,and rigorously analyze the stability and optimality of the closed-loop system.The proposed decomposition design not only bypasses the numerical stiffness but also alleviates the high-dimensionality.The efficacy of the proposed methodology is validated by a load-frequency control application of a two-area power system. 展开更多
关键词 Adaptive optimal control decentralized control output regulation reinforcement learning(RL) singularly perturbed systems(SPSs)
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Synthesis and Hydrophilic Performance of Poly(Lactic Acid)-Poly(Ethylene Glycol) Block Copolymers 被引量:2
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作者 Gang Xu Sihao Chen +2 位作者 Xiao Yan chunyu yang Zhichang Chen 《American Journal of Analytical Chemistry》 2016年第3期299-305,共7页
Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via... Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA. 展开更多
关键词 LACTIDE Poly(Lactic Acid)-Poly(Ethylene Glycol) (PLA-PEG) Prepare Hydrophily
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Stability analysis and stabilization for discrete-time singular delay systems 被引量:3
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作者 Xin Sun Qingling Zhang +1 位作者 chunyu yang Zhan Su 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第3期482-487,共6页
Stability analysis and stabilization for discrete-time singular delay systems are addressed,respectively.Firstly,a sufficient condition for regularity,causality and stability for discrete-time singular delay systems i... Stability analysis and stabilization for discrete-time singular delay systems are addressed,respectively.Firstly,a sufficient condition for regularity,causality and stability for discrete-time singular delay systems is derived.Then,by applying the skill of matrix theory,the state feedback controller is designed to guarantee the closed-loop discrete-time singular delay systems to be regular,casual and stable.Finally,numerical examples are given to demonstrate the effectiveness of the proposed method. 展开更多
关键词 discrete-time singular systems DELAY STABILITY stabilization.
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广州女性低剂量CT肺癌筛查结果及高危因素探索
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作者 卢炫庄 邱秋霞 +10 位作者 杨春玉 黎才琛 李坚福 熊珊 程博 周楚静 杜小芹 张屹 何建行 梁文华 钟南山 《中国肺癌杂志》 CAS 2024年第5期345-358,共14页
背景与目的肺癌高居中国恶性肿瘤发病率和死亡率之首。既往肺癌筛查试验大多为针对吸烟者等高危人群的选择性筛查,然而亚洲肺癌病例非吸烟女性占相当比例。本研究旨在评估广州市社区女性的肺癌患病率并探究肺癌高危因素。方法采用胸部... 背景与目的肺癌高居中国恶性肿瘤发病率和死亡率之首。既往肺癌筛查试验大多为针对吸烟者等高危人群的选择性筛查,然而亚洲肺癌病例非吸烟女性占相当比例。本研究旨在评估广州市社区女性的肺癌患病率并探究肺癌高危因素。方法采用胸部低剂量计算机断层扫描(low-dose computed tomography,LDCT)对广州市40-74岁女性居民行肺癌筛查,并根据2018版《中国肺癌低剂量螺旋CT筛查指南》对肺结节进行分类管理及计算阳性结节和肺癌检出率。筛查对象在行检查前均须完成“肺癌危险因素调研问卷”,后对问卷危险因素进行最小绝对收缩和选择算子惩罚Logistic回归分析。结果分析共纳入6256名女性,发现阳性结节1228例(19.63%),确诊肺癌117例(1.87%),其中原位癌6例,I期103例(占肺癌比例88.03%)。根据问卷变量行最小绝对收缩和选择算子(Least absolute shrinkage and selection operator,LASSO)惩罚Logistic回归分析发现,年龄≥50岁(OR=1.07,95%CI:1.06-1.07)、个人恶性肿瘤史(OR=3.29,95%CI:3.22-3.37)、纺织职业(OR=1.10,95%CI:1.08-1.13)、小时候使用煤为燃料(OR=1.14,95%CI:1.13-1.16)以及食物过敏史(OR=1.10,95%CI:1.07-1.13)是该地区女性肺癌的高危因素。结论胸部LDCT可以发现大量早期肺癌,可用于女性肺癌筛查。年龄≥50岁、个人恶性肿瘤史、纺织职业、小时候使用煤为燃料和食物过敏史是该地区女性人群肺癌的高危因素,需提高该群体对肺癌早筛的重视程度。 展开更多
关键词 肺肿瘤 低剂量CT 早期筛查 高危因素
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Variable structure control for three-variable autocatalytic reaction 被引量:2
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作者 Hong NIU Qingling ZHANG +1 位作者 chunyu yang Fenglan BAI 《控制理论与应用(英文版)》 EI CSCD 2013年第3期393-400,共8页
In this paper, two irreversible exothermic autocatalytic reactions which carry out in continuous stirred tank reactor (CSTR) are considered. A differential-algebraic system is applied to model these chemical reactio... In this paper, two irreversible exothermic autocatalytic reactions which carry out in continuous stirred tank reactor (CSTR) are considered. A differential-algebraic system is applied to model these chemical reactions. The stability and the dynamic behavior are studied for the differential-algebraic system. The Hopf bifurcation appears when the parameter exceeds a critical value. In order to eliminate this complex behavior, the differential-algebraic system is described by a single-input and single-output system with parameter varying within definite intervals, and then variable structure control with sliding mode based on a special power reaching law is designed to stabilize this chemical system. Numerical simulations are given to illustrate the effectiveness of the method. 展开更多
关键词 Differential-algebraic systems Autocatalytic reaction Hopf bifurcation Variable structure control
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