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systems Biology Approach Pinpoints Minimum Requirements for Auxin Distribution during Fruit Opening

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Molecular Plant 2019年第6期12卷 863-878页

作者： Xin-Ran Li Renske M.A.Vroomans Samantha Fox Veronica A.Grieneisen Lars Φstergaard Athanasius F.M.Maree Crop Genetics John Innes Centre Norwich NR4 7UH UK Computational and systems Biology John Innes Centre Norwich NR4 7UH UK Centre of Excellence in Computational and Experimental Developmental Biology Institute of Biotechnology University of Helsinki 00014 Helsinki Finland Cell and Developmental Biology John Innes Centre Norwich NR4 7UH UK School of Biosciences Cardiff University Cardiff CF10 3AX Wales UK

The phytohormone auxin is implied in steering various developmental decisions during plant morphogenesis in a concentration-dependent *** maxima have been shown to maintain meristematic activity,for example,of the root apical meristem,and position new sites of outgrowth,such as during lateral root initiation and *** recently,it has been demonstrated that sites of auxin minima also provide positional *** the developingArabidopsis fruit,auxin minima are required for correct differentiation of the valve *** remains unclear,however,how this auxin minimum is generated and ***,we employ a systems biology approach to model auxin transport based on experimental *** allows us to determine the minimal requirements for its *** simulations reveal that two alternative processes-which we coin "flux-barrier" and "flux-passage"-are both able to generate an auxin minimum,but under different parameter *** models are in principle able to yield similar auxin profiles but present qualitatively distinct patterns of auxin *** models were tested by tissue-specific inducible ablation,revealing that the auxin minimum in the fruit is most likely generated by a flux-passage *** predictions were further supported through 3D PIN localization imaging and implementing experimentally observed transporter *** such an experimental-modeling cycle,we predict how the auxin minimum gradually matures during fruit development to ensure timely fruit opening and seed dispersal.

关键词： auxin mathematical modeling polar auxin transport fruit development systems biology of patterning

Transfer matrix method for multibody systems(Rui method) and its applications

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Science China(Technological Sciences) 2019年第5期62卷 712-720页

作者： RUI XiaoTing WANG Xun ZHOU QinBo ZHANG JianShu Institute of Launch Dynamics Nanjing University of Science and Technology

The transfer matrix method for multibody systems, namely the "Rui method", is a new method for studying multibody system dynamics, which avoids the global dynamics equations of the system, keeps high computational speed, and allows highly formalized programming. It has been widely applied to scientific research and key engineering of lots of complex mechanical systems in 52 research directions. The following aspects regarding the transfer matrix method for multibody systems are reviewed systematically in this paper: history, basic principles, formulas, algorithm, automatic deduction theorem of overall transfer equation, visualized simulation and design software, highlights, tendency, and applications in 52 research directions in over 100 key engineering products.

关键词： multibody system dynamics transfer matrix method for multibody systems Rui method automatic deduction theorem of overall transfer equation theory computation software applications

Robust Finite-Time Guaranteed Cost Control for Positive systems with Multiple Time Delays

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Journal of systems Science & Complexity 2019年第2期32卷 496-509页

作者： THUAN Mai Viet Department of Mathematics and Informatics Thainguyen University of Science

This paper deals with the finite-time guaranteed cost control problem for positive system with multiple time delays and bounded disturbance. By using Lyapunov-Krasovskii functional method,some new sufficient conditions for the design of a state feedback controller which makes the closedloop system finite-time stable and guarantees an adequate cost level of performance are derived. Two numerical examples are also given to show the effectiveness of the proposed method.

关键词： Finite-time guaranteed cost control linear matrix inequalities Lyapunov-Krasovskii functional multiple time delays positive systems

Investigation of the stable and the metastable liquidus miscibility gaps in Fe–Sn and Fe–Cu binary systems

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1427-1435页

作者： Jiang-tao Gao Chang-rong Li Cui-ping Guo Zhen-min Du School of Materials Science and Engineering University of Science and Technology Beijing

Two kinds of experimental methods were tried in the present work:(i)the powder metallurgy method combined with differential thermal analysis(DTA)to determine the metastable liquidus miscibility gap for a Fe–Cu binary system and(ii)the high-temperature melting method combined with isothermal treatment to determine the stable liquidus miscibility gap for a Fe–Sn binary *** experimental method was adopted according to the characteristics of the liquidus miscibility gap of the specific *** the powder metallurgy method,a uniform microstructure morphology and chemical composition was obtained in the DTA specimen,and the phase-separation temperature of the supercooled metastable liquid was *** isothermal treatment was applied for the samples inside the stable liquidus miscibility gap;here,equilibrated compositions were reached,and a layered morphology was formed after rapid *** liquid miscibility gaps of the Fe–Cu and Fe–Sn binary systems were measured,and the peak temperatures of the corresponding miscibility gaps were determined to be about 1417°C at x(Cu)=0.465 at%and 1350°C at x(Sn)=0.487 at%,*** the basis of the experimental results,both the Fe–Cu and the Fe–Sn binary systems were thermodynamically assessed.

关键词： binary systems miscibility gap differential thermal analysis(DTA) metastable state

Transient Stability Analysis of Large-scale Power systems:A Survey

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CSEE Journal of Power and Energy systems 2023年第4期9卷 1284-1300页

作者： Qing-Hua Wu Yuqing Lin Chao Hong Yinsheng Su Tianhao Wen Yang Liu School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China the Power Dispatching and Control Center China Southern Power GridGuangzhou 510530China

Transient stability analysis is a key problem in power system operation and *** paper aims at giving a comprehensive review on the modeling ideas and analysis methods for transient stability of large-scale power *** model construction,the general modeling of traditional power systems and special modeling for renewable generations and high-voltage direct-current transmissions are *** transient stability analysis,Lyapunov based methods and non-Lyapunov based methods are thoroughly *** Lya-punov based methods,we focus on the energy function method,the sum-of-squares based method and decentralized stability analysis ***,in non-Lyapunov based methods,the time-domain simulation,extended equal-area criterion and data-driven based methods are *** basic working principles,features and recent research progresses of all the above-mentioned methods are described in *** particular,their performances on several aspects,such as computational speed,conservativeness of stability region estimation or stability margin calculation,and adaptability to various types of system models,are ***,a brief discussion of potential directions for future research on transient stability analysis of large-scale power systems is *** Terms-connective stability,large-scale system analysis,Lyapunov functions,power systems,transient stability analysis.

关键词： connective stability large-scale system analysis Lyapunov functions power systems transient stability analysis

Coverage-optimization based guidance of mobile agents for improved control of distributed parameter systems

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Journal of systems Engineering and Electronics 2019年第3期30卷 601-612页

作者： ZHUANG Bo CUI Baotong WU Wei JIANG Zhengxian School of Internet of Things Engineering Jiangnan University Wuxi 214122 China Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education) Wuxi 214122 China

The control problem of a class of parabolic distributed parameter systems (DPSs) is investigated by using mobile agents with capabilities of sensing and actuating. The guidance strategies of mobile agents based on coverage optimization methods are proposed to improve the control performance of the system and make the state norm of the system converge to zero faster. The coverage optimization problems are constructed based on the measurement of each agent. By solving the coverage optimization problems, the local optimal moving direction of each agent can be obtained. Then the gradient-based agent motion control laws are established. With the indicator function and the surface delta function, this method is generalized to n-dimensional space, and suitable for any sensing region with piecewise smooth boundaries. The stability and control performance of the system are analyzed. Numerical simulations show the effectiveness of the proposed methods.

关键词： distributed parameter systems (DPSs) mobile agents coverage optimization indicator function

H∞-Based Selective Inversion of Nonminimum-phase systems for Feedback Controls

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 702-710页

作者： Dan Wang Xu Chen Department of Mechanical Engineering University of WashingtonSeattleWA 98195 USA IEEE

Stably inverting a dynamic system model is fundamental to subsequent servo designs. Current inversion techniques have provided effective model matching for feedforward ***, when the inverse models are to be implemented in feedback systems, additional considerations are demanded for assuring causality, robustness, and stability under closed-loop constraints. To bridge the gap between accurate model approximations and robust feedback performances, this paper provides a new treatment of unstable zeros in inverse design. We provide first an intuitive pole-zero-map-based inverse tuning to verify the basic principle of the unstable-zero treatment. From there, for general nonminimum-phase and unstable systems, we propose an optimal inversion algorithm that can attain model accuracy at the frequency regions of interest while constraining noise amplification elsewhere to guarantee system robustness. Along the way, we also provide a modern review of model inversion techniques. The proposed algorithm is validated on motion control systems and complex high-order systems.

关键词： H∞formulation model inversion nonminimum-phase zeros unstable systems

Mean Square Average Generalized Consensus of Multi-Agent systems Under Time-Delays and Stochastic Disturbances

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Journal of systems Science & Complexity 2019年第2期32卷 588-599页

作者： QIU Li GUO Liuxiao LIU Jia School of Science Jiangnan University

Compared with the traditional consensus problem, this paper deals with the mean square average generalized consensus(MSAGC) of multi-agent systems under fixed directed topology, where all agents are affected by stochastic disturbances. Distributed protocol depending on delayed time information from neighbors is designed. Based on Lyapunov stability theory, together with results from matrix theory and It o s derivation theory, the linear matrix inequalities approach is used to establish sufficient conditions to ensure MSAGC of multi-agent systems. Finally, numerical simulations are provided to illustrate the theoretical results.

关键词： Mean square average generalized consensus multi-agent systems stochastic disturbances time delays

Robust Admissibility and Stabilization of Uncertain Singular Fractional-Order Linear Time-Invariant systems

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IEEE/CAA Journal of Automatica Sinica 2019年第3期6卷 685-692页

作者： Saliha Marir Mohammed Chadli IEEE University Mohamed Boudiaf USTO University of Picardie Jules Verne

This paper addresses the robust admissibility problem in singular fractional-order continuous time systems. It is based on new admissibility conditions of singular fractional-order systems expressed in a set of strict linear matrix inequalities(LMIs). Then, a static output feedback controller is designed for the uncertain closed-loop system to be admissible. Numerical examples are given to illustrate the proposed methods.

关键词： Control fractional-order systems linear matrix inequalities (LMIs) output feedback control robust admissibility singular systems uncertain systems