检索结果-南通市图书馆

High-Order Fully Actuated System Models for Strict-Feedback Systems With Increasing Dimensions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第12期11卷 2451-2462页

作者： xiang xu Guang-Ren Duan Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology the School of System Design and Intelligent Manufacturing Southern University of Science and Technology

This paper mainly addresses control problems of strict-feedback systems(SFSs) with increasing dimensions. Compared with the commonly-considered SFSs where the subsystems have the same dimension, we aim to handle more complex cases,i.e., the subsystems in the considered SFSs are assumed to have increasing dimensions. By transforming the systems into highorder fully-actuated system(HOFAS) models, the stabilizing controllers can be directly given. Besides first-order SFSs, secondorder and high-order SFSs are also considered.

关键词： Increasing dimensions high-order fully-actuated system nonlinear systems strict-feedback systems

Heading constraint algorithm for foot-mounted PNS using low-cost IMU

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2022年第3期33卷 727-736页

作者： GUI Jing ZHAO Heming xu xiang School of Electronic and Information Engineering Soochow UniversitySuzhou 215006China

Foot-mounted pedestrian navigation system(PNS)is a common solution to pedestrian navigation using micro-electro mechanical system(MEMS)inertial *** inherent problems of inertial navigation system(INS)by the traditional algorithm,such as the accumulated errors and the lack of observation of heading and altitude information,have become obstacles to the application and development of the *** this paper,we introduce a heuristic heading constraint *** of all,according to the movement characteristics of human gait,we use the generalized likelihood ratio test(GLRT)detector and introduce a time threshold to classify the human gait,so that we can effectively identify the stationary state of the *** addition,based on zero velocity update(ZUPT)and zero angular rate update(ZARU),the cumulative error of the inertial measurement unit(IMU)is limited and corrected,and then a heuristic heading estimation is used to constrain and correct the heading of the *** simulation and experiments with low-cost IMU,the method is proved to reduce the localization error of end-point to less than 1%of the total distance,and it has great value in application.

关键词： pedestrian navigation system(PNS) zero velocity update(ZUPT) gait detection heading constraint

INVERSION OF TRACE FORMULAS FOR A STURM-LIOUVILLE OPERATOR

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2022年第3期40卷 396-414页

作者： xiang xu Jian Zhai School of Mathematical Sciences Zhejiang UniversityHangzhouChina Institute for Advanced Study The Hong Kong University of Science and TechnologyHong KongChina

This paper revisits the classical problem“Can we hear the density of a string?”,which can be formulated as an inverse spectral problem for a Sturm-Liouville *** of inverting the map from density to spectral data directly,we propose a novel method to reconstruct the density based on inverting a sequence of trace formulas which bridge the density and its spectral data clearly in terms of a series of nonlinear integral *** experiments are presented to verify the validity and effectiveness of the proposed numerical *** impact of different parameters involved in the algorithm is also discussed.

关键词： Inverse spectral problem Sturm-Liouville operator Trace formulas

Local Stability for an Inverse Coefficient Problem of a Fractional Diffusion Equation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2014年第3期35卷 429-446页

作者： Caixuan REN xiang xu School of Mathematical Sciences Fudan University Department of Mathematics Zhejiang University Hangzhou

Time-fractional diffusion equations are of great interest and importance on describing the power law decay for diffusion in porous media. In this paper, to identify the diffusion rate, i.e., the heterogeneity of medium, the authors consider an inverse coefficient problem utilizing finite measurements and obtain a local HSlder type conditional stability based upon two Carleman estimates for the corresponding differential equations of integer orders.

关键词： Carleman estimate Conditional stability Inverse coefficient problem,Fractional diffusion equation

Investigation of Coal Fueled Chemical Looping Combustion Using Fe_3O_4 as Oxygen Carrier:Influence of Variables

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2010年第3期19卷 266-275页

作者： Xiaoyan Sun Wenguo xiang Sha Wang Wendong Tian xiang xu Yanji xu Yunhan Xiao School of Energy and Environment Southeast University Nanjing 210096 China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100080 China School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

Chemical-looping combustion (CLC) is a novel combustion technique with inherent CO2 *** (Fe3O4) was selected as the oxygen *** coal (Inner Mongolia,China),straw coke and natural coke were used as fuels for this *** of operation temperatures,coal to Fe3O4 mass ratios,and different kinds of fuels on the reduction characteristics of the oxygen carrier were investigated using an atmosphere thermogravimetric analyzer (TGA).Scanning electron microscopy (SEM) was used to analyse the characteristic of the solid *** results shown that the reaction between the coal and the oxygen carrier become strong at a temperature of higher than 800℃.As the operation temperature rises,the reduction conversion rate *** the temperatures of 850oС,900℃,and 950℃,the reduction conversion rates were 37.1%,46.5%,and 54.1% ***,SEM images show that at the temperature of higher than 950℃,the iron oxides become melted and *** possible operation temperature should be kept around 900℃.When the mass ratios of coal to Fe3O4 were 5/95,10/90,15/85,and 20/80,the reduction conversion rates were 29.5%,40.8%,46.5%,and 46.6% *** the increase of coal,the conversion rate goes *** there exist an optimal ratio around 15/*** based on different kinds of fuels show that the solid fuel with a higher volatile and a more developed pore structure is conducive to the reduction reactivity of the oxygen carrier.

关键词： chemical-looping combustion CO2 separation magnetite

Consensus of Single Integrator Multi-Agent Systems with Unbounded Transmission Delays

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2019年第3期32卷 778-788页

作者： xu xiang LIU Lu FENG Gang Department of Biomedical Engineering City University of Hong Kong

This paper investigates the consensus problem of single integrator multi-agent systems with unbounded time-varying transmission delays and fixed di rec ted topology. A dist ributed cont roller is proposed taking into consideration the unbounded transmission delays. It is shown that the consensus problem can be solved via the proposed controller under the spanning tree assumption and the nocycle assumption. The authors characterize the no-cycle assumption and prove the consensus of the concerned multi-agent systern with an induction procedure. Two simulation examples are provided, one to illustrate the effectiveness of our result and the other to show the necessity of the no-cycle assumption.

关键词： Consensus multi-agent systems unbounded transmission delays

ON SPECTRAL METHODS FOR VOLTERRA INTEGRAL EQUATIONS AND THE CONVERGENCE ANALYSIS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2008年第6期26卷 825-837页

作者： Tao Tang xiang xu Jin Cheng Department of Mathematics Hong Kong Baptist University Kowloon Tong Hong Kong China School of Mathematics Fudan University Shanghai 200433 China

The main purpose of this work is to provide a novel numerical approach for the Volterra integral equations based on a spectral approach. A Legendre-collocation method is proposed to solve the Volterra integral equations of the second kind. We provide a rigorous error analysis for the proposed method, which indicates that the numerical errors decay exponentially provided that the kernel function and the source function are sufficiently smooth. Numerical results confirm the theoretical prediction of the exponential rate of convergence. The result in this work seems to be the first successful spectral approach （with theoretical justification） for the Volterra type equations.

关键词： Legendre-spectral method Second kind Volterra integral equations Convergence analysis.

Analysis of structural response under blast loads using the coupled SPH-FEM approach

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第9期9卷 1184-1192页

作者： Jun-xiang xu Xi-la LIU Department of Civil Engineering Shanghai Jiao Tong University Shanghai 200240 China

A numerical model using the coupled smoothed panicle hydrodynamics-finite element method （SPH-FEM） approach is presented for analysis of structures under blast loads. The analyses on two numerical cases, one for free field explosive and the other for structural response under blast loads, are performed to model the whole processes from the propagation of the pressure wave to the response of structures. Based on the simulation, it is concluded that this model can be used for reasonably accurate explosive analysis of structures. The resulting information would be valuable for protecting structures under blast loads.

关键词： Smoothed particle hydrodynamics (SPH) Finite element method (FEM) Reinforced concrete structure Explosion

Theoretical studies on the complexation of uranyl with typical carboxylate and amidoximate ligands

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2013年第11期56卷 1525-1532页

作者： xu ChaoFei SU Jing xu xiang LI Jun Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education Tsinghua University Division of Nuclear Materials Science and Engineering Shanghai Institute of Applied PhysicsChinese Academy of Sciences Key Laboratory of Nuclear Radiation and Nuclear Energy Technology Chinese Academy of Sciences College of Chemistry and Pharmaceutical Sciences Qingdao Agricultural University

Understanding of the bonding nature of uranyl and various ligands is the key for designing robust sequestering agents for uranium extraction from seawater. In this paper thermodynamic properties related to the complexation reaction of uranyl（VI） in aqueous solution （i.e. existing in the form of UO2（H20）52＋） by several typical ligands （L） including acetate （CH3CO2）, bicar- bonate （HOCO2-）, carbonate （CO32-）, CH3（NH2）CNO- （acetamidoximate, AO-） and glutarimidedioximate （denoted as GDO2-） have been investigated by using relativistic density functional theory （DFT）. The geometries, vibrational frequencies, natural net charges, and bond orders of the formed uranyl-L complexes in aqueous solution are studied. Based on the DFT analysis we show that the binding interaction between uranyl and amidoximate ligand is the strongest among the selected complexes. The thermodynamics of the complexation reaction are examined, and the calculated results show that complexation of uranyl with amidoximate ligands is most preferred thermodynamically. Besides, reaction paths of the substitution complexation of solvated uranyl by acetate and AO have been studied, respectively. We have obtained two minima along the reaction path of solvated uranyl with acetate, the monodentate-acetate complex and the bidentate-acetate one, while only one minimum involving monodentate-AO complex has been located for AO- ligand. Comparing the energy barriers of the two reaction paths, we find that complexation of uranyl with AO is more difficult in kinetics, though it is more preferable in thermodynamics. These results show that theoretical studies can help to select efficient ligands with fine-tuned thermodynamic and kinetic properties for binding uranyl in seawater.

关键词： uranyl seawater carboxylate amidoximate complexation thermodynamics density functional theory