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6th IFAC Symposium on Nonlinear control Systems, NOLCOS 2004

作者： Goebel, Rafal Hespanha, Joao Teel, Andrew R. Cai, Chaohong Sanfelice, Ricardo Center for Control Engineering and Computation and Electrical and Computer Engineering Department University of California Santa BarbaraCA93106-9560 United States

Robust asymptotic stability for hybrid systems is considered. For this purpose, a generalized solution concept is developed. The first step is to characterize a hybrid time domain that permits an efficient description of the convergence of a sequence of solutions. Graph convergence is used. Then a generalized solution definition is given that leads to continuity with respect to initial conditions and perturbations of the system data. This property enables new results on necessary conditions for asymptotic stability in hybrid systems. Copyright © 2004 IFAC.

关键词： Lyapunov functions

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Long-lived Zone-boundary Magnons in an Antiferromagnet

arXiv

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arXiv 2025年

作者： Choe, Jeongheon Lujan, David Ye, Gaihua Nnokwe, Cynthia Ma, Bowen He, Jiaming Gao, Frank Y. Nunley, T. Nathan Leonardo, Aritz Arruabarrena, Mikel Ayuela, Andres Zhou, Jianshi Rodriguez-Vega, Martin Fiete, Gregory A. He, Rui Li, Xiaoqin Department of Physics Center for Complex Quantum Systems The University of Texas at Austin AustinTX78712 United States Center for Dynamics and Control of Materials The University of Texas at Austin AustinTX78712 United States Department of Electrical and Computer Engineering Texas Tech University LubbockTX79409 United States Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States EHU Quantum Center University of the Basque Country UPV/EHU Bilbao Spain Donostia20018 Spain Department of Physics Northeastern University BostonMA02115 United States Quantum Materials and Sensing Institute Northeastern University BurlingtonMA01803 United States Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States

Antiferromagnetic (AFM) insulators exhibit many desirable features for spintronic applications such as fast dynamics in the THz range and robustness to fluctuating external fields. However, large damping typically associated with THz magnons presents a serious challenge for THz magnonic applications. Here, we report long-lived short-wavelength zone boundary magnons in the honeycomb AFM insulator CoTiO3, recently found to host topological magnons. We find that its zone-boundary THz magnons exhibit longer lifetimes than its zone-center magnons. This unusual momentum-dependent long magnon lifetime originates from several factors including the antiferromagnetic order, exchange anisotropy, a finite magnon gap, and magnon band dispersion. Our work suggests that magnon-magnon interaction may not be detrimental to magnon lifetimes and should be included in future searches for topological magnons. © 2025, CC BY.

关键词： Antiferromagnetic materials

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Consensus Problem in General Linear Multiagent Systems Under Stochastic Topologies

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IFAC-PapersOnLine 2016年第13期49卷 13-18页

作者： Rezaee, Hamed Abdollahi, Farzaneh The Center of Excellence on Control and Robotics Department of Electrical Engineering Amirkabir University of Technology Tehran Iran Department of Electrical and Computer Engineering Concordia University MontrealQuebec Canada

Consensus control of a class of multiagent systems with general linear dynamics is studied. Based on solution of some linear matrix inequalities, a protocol is obtained which guarantees achieving consensus among agents in the presences of stochastically switching topologies. By invoking the concept super-martingales, it is shown that if the probability of the network connectivity is not zero, the agents reach almost sure consensus upon their state vectors. Despite existing results in the literature for consensus control of general linear multiagent systems under stochastic networks, the proposed consensus protocol in this paper requires no knowledge on the set of feasible topologies, and this issue significantly decreases the design computational costs. Simulation results for a diving consensus problem among a team of autonomous underwater vehicles validate the proposed consensus protocol. © 2016

关键词： Multi agent systems Autonomous underwater vehicles Linear matrix inequalities Stochastic systems Topology Almost sure consensus computational costs Consensus problems Consensus protocols Linear dynamics Network connectivity Of autonomous underwater vehicles Stochastic networks

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Intent Pattern Recognition of Lower-limb Motion Based on Mechanical Sensors

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IEEE/CAA Journal of Automatica Sinica 2017年第4期4卷 651-660页

作者： Zuojun Liu Wei Lin Yanli Geng Peng Yang School of Control Science and Engineering Hebei University of Technology Engineering Research Center of Intelligent Rehabilitation Ministry of Education Department of Electrical Engineering and Computer Science Case Western Reserve University Hebei University of Technology

Based on the regularity nature of lower-limb motion,an intent pattern recognition approach for above-knee prosthesis is proposed in this paper. To remedy the defects of recognizer based on electromyogram(EMG), we develop a pure mechanical sensor architecture for intent pattern recognition of lower-limb motion. The sensor system is composed of an accelerometer, a gyroscope mounted on the prosthetic socket, and two pressure sensors mounted under the sole. To compensate the delay in the control of prosthesis, the signals in the stance phase are used to predict the terrain and speed in the swing phase. Specifically, the intent pattern recognizer utilizes intraclass correlation coefficient(ICC) according to the Cartesian product of walking speed and terrain. Moreover, the sensor data are fused via DempsterShafer's theory. And hidden Markov model(HMM) is used to recognize the realtime motion state with the reference of the prior step. The proposed method can infer the prosthesis user's intent of walking on different terrain, which includes level ground,stair ascent, stair descent, up and down ramp. The experiments demonstrate that the intent pattern recognizer is capable of identifying five typical terrain-modes with the rate of 95.8%. The outcome of this investigation is expected to substantially improve the control performance of powered above-knee prosthesis.

关键词： Above-knee prosthesis hidden Markov model(HMM) intra-class correlation coefficient(ICC) intent pattern recognition sensor fusion

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Distributed Constrained Online Nonconvex Optimization with Compressed Communication

arXiv

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arXiv 2025年

作者： Zhang, Kunpeng Xu, Lei Yi, Xinlei Cao, Ming Johansson, Karl H. Chai, Tianyou Yang, Tao State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China Department of Mechanical Engineering University of Victoria VictoriaBCV8W 2Y2 Canada Shanghai Institute of Intelligent Science and Technology National Key Laboratory of Autonomous Intelligent Unmanned Systems Frontiers Science Center for Intelligent Autonomous Systems Ministry of Education Shanghai201210 China Engineering and Technology Institute Groningen Faculty of Science and Engineering University of Groningen GroningenAG 9747 Netherlands Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Sweden Digital Futures Stockholm10044 Sweden

This paper considers distributed online nonconvex optimization with time-varying inequality constraints over a network of agents. For a time-varying graph, we propose a distributed online primal–dual algorithm with compressed communication to efficiently utilize communication resources. We show that the proposed algorithm establishes an O(T max{1−θ1,θ1}) network regret bound and an O(T 1−θ1/2) network cumulative constraint violation bound, where T is the number of iterations and θ1 ∈ (0, 1) is a user-defined trade-off parameter. When Slater’s condition holds (i.e, there is a point that strictly satisfies the inequality constraints at all iterations), the network cumulative constraint violation bound is reduced to O(T 1−θ1). These bounds are comparable to the state-of-the-art results established by existing distributed online algorithms with perfect communication for distributed online convex optimization with (time-varying) inequality constraints. Finally, a simulation example is presented to validate the theoretical results. Copyright © 2025, The Authors. All rights reserved.

关键词： Convex optimization

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Active disturbance rejection control： between the formulation in time and the understanding in frequency

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control Theory and Technology 2016年第3期14卷 250-259页

作者： Qing ZHENG Zhiqiang GAO Department of Electrical and Computer Engineering Gannon University Erie PA 16541 U.S.A. Center for Advanced Control Technologies Department of Electrical and Computer Engineering Cleveland State University Cleveland OH 44115 U.S.A.

With the rapid deployments of the active disturbance rejection control （ADRC） as a bonafide industrial technology in the background, this paper summarizes some recent results in the analysis of linear ADRC and offers explanations in the frequency response language with which practicing engineers are familiar. Critical to this endeavor is the concept of bandwidth, which has been used in a more general sense. It is this concept that can serve as the link between the otherwise opaque state space formulation of the ADRC and the command design considerations and concerns shared by practicing engineers. The remarkable characteristics of a simple linear ADRC was first shown in the frequency domain, followed by the corresponding analysis in time domain, where the relationship between the tracking error and the ADRC bandwidth is established. It is shown that such insight is only possible by using the method of solving linear differential equations, instead of the more traditional techniques such as the Lyapunov methods, which tend to be more conservative and difficult to grasp by engineers. The insight obtained from such analysis is further demonstrated in the simulation validation.

关键词： Active disturbance rejection control extended state observer uncertain systems stability bandwidth

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Luminescence of carbon nanotube bulbs

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Chinese Science Bulletin 2007年第1期52卷 113-117页

作者： LI ChuanGang WANG KunLin WEI JinQuan WEI BingQing ZHU HongWei WANG ZhiCheng LUO JianBin LIU WenJin ZHENG MingXin WU DeHai Department of Mechanical Engineering Tsinghua University Beijing 100084 China Department of Electrical & Computer Engineering and Center for Computation & Technology Louisiana State University Baton Rouge LA 70803 USA

Carbon nanotube (CNT) bulbs made of decimeter-scale double-walled carbon nanotube (DWCNT) strands and films were fabricated and their luminescence properties, including the lighting efficiency, voltage-current relation and thermal stability were investigated. The results show that the DWCNT bulb has a comparable spectrum of visible light with tungsten bulb and its average efficiency is 40% higher than that of a tungsten filament at the same temperature (1400―2300 K). The nanotube filaments show both resistance and thermal stability over a large temperature region. No obvious damage was found for a nanotube bulb illuminating at 2300 K for more than 24 hours in vacuum.

关键词：碳纳米管灯管发光性电子产品

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New results in global stabilization for stochastic nonlinear systems

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control Theory and Technology 2016年第1期14卷 57-67页

作者： Tao BIAN Zhong-Ping JIANG Control and Networks Lab Department of Electrical and Computer Engineering Tandon School of Engineering New York University 5 Metrotech Center Brooklyn NY 11201 U.S.A.

This paper presents new results on the robust global stabilization and the gain assignment problems for stochastic nonlinear systems. Three stochastic nonlinear control design schemes are developed. Furthermore, a new stochastic gain assignment method is developed for a class of uncertain interconnected stochastic nonlinear systems. This method can be combined with the nonlinear small-gain theorem to design partial-state feedback controllers for stochastic nonlinear systems. Two numerical examples are given to illustrate the effectiveness of the proposed methodology.

关键词： Stochastic nonlinear systems stochastic input-to-output stability stabilization gain assignment small-gain

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Synthesis of churros-like V2Se9 nanostructures for ultrasensitive electrochemical detection of oxalic acid in urine with portable point-of-care diagnostic devices

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Biosensors and Bioelectronics 2025年 285卷 117589页

作者： Shi, Peizheng Ye, Chen Sun, Zhuang Sun, Kaiqiang Zhao, Ningbin Pourfakhr, Mahan Cai, Tao Nishimura, Kazuhito Jiang, Nan Tsai, Hsu-Sheng Wu, Lidong Wu, Wenqi Yu, Jiancheng Fu, Li Xu, Lixin Chen, Jun Lin, Cheng-Te College of Materials Science and Engineering Zhejiang University of Technology Hangzhou310014 China Qianwan Institute of CNITECH Ningbo315336 China State Key Laboratory of Advanced Marine Materials Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo315201 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China Department of Bioengineering University of California Los AngelesCA90095 United States School of Physics Harbin Institute of Technology Harbin150001 China Key Laboratory of Control of Quality and Safety for Aquatic Products Chinese Academy of Fishery Sciences Beijing100141 China Department of Urology The Second Affiliated Hospital of Guangzhou Medical University Guangdong 510260 China Guangdong Key Laboratory of Urology Guangzhou Medical University Guangdong 511495 China Institute of Mass Spectrometry Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application Ningbo University Ningbo315211 China Zhenhai Institute of Mass Spectrometry Ningbo315211 China Faculty of Electrical Engineering and Computer Science Ningbo University Ningbo315211 China College of Materials and Environmental Engineering Hangzhou Dianzi University Hangzhou310018 China

The binding of oxalic acid (OA) with metal ions, particularly calcium ions, is a key factor in kidney stone formation, as it produces insoluble calcium oxalate, which crystallizes and accumulates in the kidneys. Consequently, OA in urine is commonly considered a significant biomarker for clinical diagnosis and early screening of kidney stones. This study reports churros-like V2Se9 nanostructures synthesized using a solvothermal method (high pressure and temperature) for sensitive and selective electrochemical detection of OA in urine. The electrodes made of churros-like V2Se9 hybridized with reduced graphene oxide (rGO) for OA recognition, demonstrated a linear range from 20 nM to 4 mM, with an extremely low detection limit of 9.7 nM. To enable fast, user friendly, and accurate point-of-care testing (POCT) for OA in urine samples, we designed and developed a portable workstation integrated with smartphone for data visualization. This is the first study to utilize the V2Se9 system for highly sensitive biosensor applications, highlighting its potential to advance screening techniques for key indicators of kidney stones by incorporating novel transition metal chalcogenide nanomaterials in POCT devices. © 2025 Elsevier B.V.

关键词： Electrochemical biosensors

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Optimal sensors and actuators placement for large-scale switched systems

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International Journal of Dynamics and control 2019年第1期7卷 147-156页

作者： Seyed Sakha, Masoud Shaker, Hamid Reza Tahavori, Maryamsadat Department of Control Engineering Faculty of Electrical and Computer Engineering University of Tabriz Tabriz Iran Center for Energy Informatics University of Southern Denmark Odense Denmark

The problem of sensor and actuator placement is computationally expensive in particular in dealing with large-scale systems. This problem is even more computationally intensive in the case of switched systems. In this paper, we propose a new numerical approach for sensor and actuator placement for large-scale switched systems. We first introduce restricted genetic algorithm (RGA). RGA is an evolutionary algorithm which is developed specifically for sensors and actuator placement. We then use RGA to reduce the computational burden of the sensor and actuator placement for switched system. The proposed method uses the generalized gramians for switched systems which are called nice gramians. The nice gramians quantify the level of observability and reachability of switched systems. To the best of our knowledge, this paper presents the first results on sensor and actuator placement of switched systems. We show the effectiveness of the approach with the help of numerical examples. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

关键词： Genetic algorithms

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