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Concave group methods for variable selection and estimation in high-dimensional varying coefficient models

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Science China Mathematics 2014年第10期57卷 2073-2090页

作者： YANG guangren HUANG Jian ZHOU Yong Department of Statistics School of EconomicsJinan University School of Statistics and Management Shanghai University of Finance and Economics Department of Statistics and Actuarial Science University of Iowa Academy of Mathematics and Systems Science Chinese Academy of Sciences

The varying-coefficient model is flexible and powerful for modeling the dynamic changes of regression coefficients. We study the problem of variable selection and estimation in this model in the sparse, high- dimensional case. We develop a concave group selection approach for this problem using basis function expansion and study its theoretical and empirical properties. We also apply the group Lasso for variable selection and estimation in this model and study its properties. Under appropriate conditions, we show that the group least absolute shrinkage and selection operator （Lasso） selects a model whose dimension is comparable to the underlying mode], regardless of the large number of unimportant variables. In order to improve the selection results, we show that the group minimax concave penalty （MCP） has the oracle selection property in the sense that it correctly selects important variables with probability converging to one under suitable conditions. By comparison, the group Lasso does not have the oracle selection property. In the simulation parts, we apply the group Lasso and the group MCP. At the same time, the two approaches are evaluated using simulation and demonstrated on a data example.

关键词： basis expansion group lasso group MCP high-dimensional data sparsity oracle property

On-line optimal autonomous reentry guidance based on improved Gauss pseudospectral method

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Science China(Information Sciences) 2014年第5期57卷 244-259页

作者： SUN Yong HOU MingZhe DUAN guangren LIANG XiaoLing Center for Control Theory and Guidance Technology Harbin Institute of Technology Nanjing Research Institute of Electronics Technology

The on-line optimal autonomous reentry guidance of the hypersonic vehicle is proposed based on the improved Gauss pseudospectral method(IGPM).The autonomous reentry guidance requires the hypersonic vehicle can generate the optimal trajectory for the latest flight mission on line and track the new trajectory well under the *** two problems are simplified into a nonlinear optimal control problem with nonlinear *** IGPM is introduced to solve the above two *** trajectory has to change according to the flight mission and therefore the new optimal trajectory can be obtained by IGPM within about10 *** optimal feedback guidance law is used to track the reference trajectory to handle the *** order to deal with the CPU time delay,which comes from optimizing the new trajectory,the new on-line optimal autonomous reentry guidance is ***,the numerical simulation shows that the proposed autonomous guidance can generate optimal trajectory for the new flight mission and have a high tracking accuracy.

关键词： optimal autonomous reentry guidance improved gauss pseudospectral method hypersonic vehicle optimal feedback guidance

Discrete-time delay systems: part 2. Sub-fully actuated case

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Science China(Information Sciences) 2022年

作者： guangren DUAN Center for Control Theory and Guidance Technology Harbin Institute of Technology Center for Control Science and Technology Southern University of Science and Technology

In continuation to the first part of the paper, this second part further investigates the models and control of discrete-time sub-fully actuated systems with time-varying delays. Firstly, a new representation for general linear and nonlinear dynamical discrete-time fully actuated systems(FASs) with time-varying state delays and constant input delays is proposed, and the concept of sub-FAS is defined. The set of feasible points and the set of singular points for a sub-FAS are introduced. Secondly, like the global FAS case, controllers for a discrete-time sub-FAS can also be easily designed, which results in constant linear closed-loop systems with arbitrarily assignable eigenstructures, but unlike the global FAS case, a constraint must be added,which is expressed by the set of feasible points of the system and guarantees the realizability of the designed controllers. Finally, a general definition for controllable dynamical systems with time delays is given.

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Extractive denitrogenation of shale oil using imidazolium ionic liquids

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Green Energy & Environment 2020年第2期5卷 173-182页

作者： Shurong Gao Shengfan Fang Ruozheng Song Xiaochun Chen guangren Yu Research Center of Engineering Thermophysics North China Electric Power UniversityBeijing 102206China Beijing Key Laboratory of Membrane Science and Technology&College of Chemical Engineering Beijing University of Chemical TechnologyBeijing 100029China

The potential applications of shale oil as a substitute energy source are adversely influenced due to its high nitrogen *** this work,four imidazolium ionic liquids(ILs),i.e.,1-butyl-3-methylimidazolium chloride([Bmim]Cl),1-butyl-3-methylimidazolium acetate([Bmim]Ac),1-butyl-3-methylimidazolium acetate/ZnAc2([Bmim]Ac/ZnAc2)and 1-butyl-3-methylimidazolium chloride/ZnAc2([Bmim]Cl/ZnAc2),were used to extract the basic nitrides and neutral nitrides from shale *** influence of extraction time,temperature,properties of N-compounds,ILs structure,mass ratio of IL/oil,multiple cycles of denitrogenation,physical mixing of ILs and ILs recyclability on extractive denitrogenation was systematically *** denitrogenation performance of all ILs was determined and investigated from micro-level view withσ-*** was observed that,ILs composed of anions with weaker HB acceptor capacity,have the higher N-extraction efficiency to the neutral nitrogen compounds with weaker HB acceptor *** than 96%N-extraction efficiency was achieved at the end of a single extraction cycle for time<10 min under 40℃C and 1:1 of IL:oil(w/w),especially 100%N-extraction efficiency was realized for carbazole and *** N-extraction efficiency up to 60.1%and 53.7%for real shale oil was realized by[Bmim]Ac and[Bmim]Ac/ZnAc2,respectively,which are about 10%better than other non-hydrodenitrogenation ***,[Bmim]Ac and[Bmim]Ac/ZnAc2 exhibited almost the same extractive denitrogenation performance after *** work has developed a new approach to lessen the nitrogen content of shale oil effectively and economically.

关键词： Shale oil Denitrogenation Ionic liquids Basic nitride Neutral nitride

N-methyl-2-pyrrolidonium-based Br?nsted-Lewis acidic ionic liquids as catalysts for the hydrolysis of cellulose

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Science China Chemistry 2016年第5期59卷 564-570页

作者： Zheng Zhao Na Li Abdul Waheed Bhutto Ahmed A. Abdeltawab Salem S. Al-Deyab Guangqing liu Xiaochun Chen guangren Yu Beijing Key Laboratory of Membrane Science and Technology College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Department of Chemical Engineering Mehran University of Engineering and TechnologyJamshoro 76062Pakistan Petrochemicals Research Chair College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia

We experimentally studied the catalytic performances of a series of Brrnsted-Lewis acidic N-methyl-2-pyrrolidonium metal chlorides （[Hnmp]Cl/MClx, where M=Fe, Zn, A1, or Cu） for the hydrolysis of microcrystalline cellulose （MCC） and cotton to produce reducing sugar. A variety of factors, such as temperature, time, ionic liquid （IL） species, IL dosage, and the concentra- tion of the metal chloride were investigated. [Hnmp]Cl/FeCl3 presented the best hydrolysis performance, affording a 98.8% yield of total reducing sugar from MCC （1 h, 100 ℃, 0.1 g MCC, 0.2 g acidic IL, 2.0 g [Bmim]Cl as solvent）, which is better than or comparable to results previously obtained with other -SO3H functionalized acidic ILs. The hydrolysis performances of [Hnmp]Cl/MClx were rationalized using density functional theory calculations, which indicated that interactions between the metal chlorides and the cellulose, including charge-transfer interactions are important in the hydrolysis of cellulose and degra- dation of glucose. This work shows that Bronsted-Lewis acidic ILs are potential catalysts for the hydrolysis of cellulose to produce sugar.

关键词： cellulose hydrolysis ionic liquid density functional theory

Design of unknown input observer with H_∞ performance for linear time-delay systems

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Journal of Systems Engineering and Electronics 2006年第3期17卷 606-610页

作者： Fu Yanming Wu Di Zhang Peng Duan guangren Center for Control Theory and Guidance Technology Harbin Inst. of Technology Harbin 150001 P. R. China

A unknown input observer （UIO） design for a class of linear time-delay systems when the observer error can＇t completely decouple from unknown input is dealt with. A sufficient condition to its existence is presented based on Lyapunov stability method. Design problem of the proposed observer is formulated in term of linear matrix inequalities. Two design problems of the observer with internal delay and without internal delay are formulated. Based on H∞ control theory in time-delay systems, the proposed observer is designed in term of linear matrix inequalities （LMI）. A design algorithm is proposed. The effective of the proposed approach is illustrated by a numerical example.

关键词： unknown input observer time-delay systems linear matrix inequalities.

GLOBAL STABILIZATION OF LINEAR SYSTEMS WITH BOUNDED CONTROLS USING STATE-DEPENDENT SATURATION FUNCTIONS

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Journal of Systems Science & Complexity 2011年第3期24卷 477-490页

作者： Bin ZHOU guangren DUAN He KONG Center for Control Theory and Guidance Technology Harbin Institute of Technology Harbin 150001 China.

By using the so-called SP-stable polynomials, this paper reconsiders the problem of global stabilization of linear systems with input saturation. Firstly, a new nonlinear feedback law consisting of parallel connections of saturation functions by means of the so-called state-dependent saturation function is proposed for global stabilization of chains of integrators system. The state-dependent saturation function allows increasing the control energy when some of the states are badly scaled and can improve significantly the transient performances of the closed-loop system. Secondly, this type of global stabilization nonlinear feedback laws is extended to a class of linear systems that can be globally stabilized by bounded controls. Numerical examples show the effectiveness of the proposed approach.

关键词： Bounded feedback global stabilization nonlinear control state-dependent saturation functions SP-stable polynomials.

Characteristics and mechanisms of sorption of organic contaminants onto sodium dodecyl sulfate modified Ca-Al layered double hydroxides

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Chinese Science Bulletin 2011年第32期56卷 3431-3436页

作者： RUAN XiuXiu SUN Peng OUYANG XingXing QIAN guangren School of Environmental and Chemical Engineering Shanghai University Shanghai 200444 China

A series of calcium aluminum layered double hydroxides (LDHs) modified with sodium dodecyl sulfate (SDS) (Ca/Al-SDS-LDHs) were synthesized by co-precipitation, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and elemental analysis. The Ca/Al-SDS-LDHs enhanced sorption of nitrobenzene and naphthalene from water compared with inor- ganic LDH (Ca/Al-Cl-LDH). The sorption isotherms for sorption of organic contaminants onto the Ca/Al-SDS-LDHs were linear for the concentration range tested, which implies that the sorption mechanism is mainly by partition. The sorption of naphthalene onto Ca/Al-SDS-LDH was apparently stronger than that of nitrobenzene, but this order reversed after eliminating the hydrophobic effect of these two contaminants. Because naphthalene is non-polar and nitrobenzene is polar, the results indicate that the Ca/AlSDS-LDHs were selective for polar organic contaminants.

关键词：层状双金属氢氧化物十二烷基硫酸钠有机污染物吸附特性修改傅里叶变换红外光谱机制 LDHs

Adaptive dynamic surface control of high-order strict feedback nonlinear systems with parameter estimations

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Science China(Information Sciences) 2023年第5期66卷 293-294页

作者： Mingzhe HOU Wenrui SHI Leyan FANG guangren DUAN Center for Control Theory and Guidance Technology Harbin Institute of Technology

Dear editor,The dynamics of system components is usually governed by high-order diferential equations in engineering ***, these high-order systems are mostly converted into first-order systems and treated within the framework of firstorder systems. Recently, Duan [1] showed that more direct and efective control algorithms can be designed if the conversion process is saved. Based on this idea,

关键词： Low pass filters