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Sliding modes: from asymptoticity, to finite time and fixed time

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Science China(Information Sciences) 2023年第9期66卷 64-77页

作者： wenwu yu Xinghuo yu He WANG School of Mathematics Southeast University Purple Mountain Laboratories School of Electrical and Computer Engineering RMIT University

This paper proposes a new fixed-time sliding mode(FSM) control, where the settling time for reaching the system origin is bounded to a constant independent of the initial condition; this is in contrast to the initial condition-dependent constants used in the traditional linear sliding mode(LSM) and terminal sliding mode(TSM) controls. First, a new sliding mode control with a single power term is discussed, where the power term can have any nonnegative value. Except for the traditional LSM and TSM controls, a new sliding mode control called power sliding mode(PSM) is proposed, whose power term is larger than 1. Then,a new FSM control with two power terms is investigated, whose design is based on the combination of TSM and PSM. In particular, the two power terms on the plane in the first quadrant are carefully discussed, and a detailed classification is provided. Here, the first quadrant can be classified into six categories, including LSM, generalized LSM, TSM, fast TSM(FTSM), PSM, and FSM. Furthermore, the analytical settling time is calculated, and three different estimation bounds of the settling time are given for reaching the origin under any initial condition. It is also interesting to derive the lowest bound for the settling time. Finally,FSM control design for general nonlinear dynamical systems with the relative degree from the control input to the output is also discussed.

关键词： sliding mode control fixed-time sliding mode linear sliding mode terminal sliding mode power sliding mode nonlinear systems

A distributed coding-decoding-based Nash equilibrium seeking algorithm over directed communication network

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Science China(Technological Sciences) 2023年第7期66卷 1975-1986页

作者： RAO XinPei XU WenYing YANG ShaoFu yu wenwu School of Mathematics Southeast UniversityNanjing 211189China School of Computer Science and Engineering Southeast UniversityNanjing 211189China Purple Mountain Laboratories Nanjing 211111China

This paper is concerned with the distributed Nash equilibrium(NE) computation problem for non-cooperative games subject to partial-decision *** the purpose of congestion mitigation,coding-decoding-based schemes are constructed on the basis of logarithmic and uniform quantizers,*** be specific,the data(decision variable) are first mapped to codewords by an encoder scheme,and then sent to the neighboring agents through a directed communication network(with non-doubly stochastic weighted matrix).By using a decoder scheme,a new distributed algorithm is established for seeking the *** order to eliminate the convergence error caused by quantization,a dynamic variable is introduced and a modified codingdecoding-based algorithm is constructed under the uniform quantization scheme,which ensures the asymptotic convergence to the *** proposed algorithm only requires that the weighted adjacency matrix is row stochastic instead of double ***,one numerical example is provided to validate the effectiveness of our algorithms.

关键词： non-cooperative games quantization coding-decoding projected pseudo-gradient dynamics

A chattering free consensus controller for multiple Lur'e systems with a non-autonomous leader and directed switching topology

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Science China(Technological Sciences) 2023年第4期66卷 1110-1118页

作者： WANG PeiJun yu wenwu WEN GuangHui yu XingHuo HUANG TingWen School of Mathematics and Statistics Anhui Normal UniversityWuhu 241000China Anhui Province Engineering Laboratory of Intelligent Robot's Information Fusion and Control Anhui Normal UniversityWuhu 241000China School of Mathematics Frontiers Science Center for Mobile Information Communication and SecuritySoutheast UniversityNanjing 210096China Purple Mountain Laboratories Nanjing 21111lChina Department of Electrical Engineering Nantong UniversityNantong 226019China Department of Systems Science School of MathematicsSoutheast UniversityNanjing 210096China School of Engineering RMIT UniversityMelbourne VIC 3001Australia Science Program Texas A&M University at QatarDoha 23874Qatar

Achieving asymptotical cooperative goal for multi-agent systems(MASs)with non-autonomous leaders(i.e.,leaders with nonzero inputs)is a critical but challenging *** approach is to use discontinuous controllers which may cause chattering phenomenon in practical *** to achieve the asymptotical goal via a chattering free cooperative controller remains to be open so *** this paper,an adaptive continuous controller is designed to achieve zero error consensus tracking in multiple Lur’e systems with a non-autonomous leader under directed switching ***,an unknown input observer(UIO)based on relative outputs is given to estimate the relative full *** an adaptive continuous controller is designed by introducing a decay function which remains positive into the term that plays the role of eliminating the impacts of leader’s nonzero ***,by using multiple Lyapunov functions(MLFs)technique,it is proven that zero error consensus tracking can be achieved if the average dwell time(ADT)is greater than a positive ***,theoretical result is verified by performing simulations on Chua’s *** with existing work,the proposed controller can not only achieve asymptotical consensus,but also is chattering free.

关键词： multi-agent system consensus chattering free non-autonomous leader directed switching topology

Finite-Time Attack Detection and Secure State Estimation for Cyber-Physical Systems

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自动化学报:英文版 2023年第10期10卷 2032-2034页

作者： Mi Lv yuezu Lv wenwu yu Haofei Meng School of Cyber Science and Engineering Southeast UniversityNanjing 210096China School of Mathematics Southeast UniversityNanjing 210096China School of Automation Southeast UniversityNanjing 210096China

Dear Editor, This letter aims to investigate the problem of attack detection and state estimation when the system suffers from external malicious attacks. A finite-time reduce-order observer is designed, which can achieve attack detection at the preset time instant. Meanwhile, it is shown that the protection of the key nodes greatly improves the efficiency of secure state estimation. Finally, the proposed theory is applied to a general cyber-physical system to illustrate its effectiveness.

关键词： estimation Secure system

Robust adaptive time-varying region tracking control of multi-robot systems

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Science China(Information Sciences) 2023年第5期66卷 291-292页

作者： Junjie FU yuezu LV wenwu yu Jiangsu Key Laboratory of Networked Collective Intelligence School of Mathematics Southeast University

Dear editor,Multi-robot systems have been employed in more and more areas in recent years due to their high efficiency, low cost and impressive robustness. When the number of agents is large, efective control of the multi-agent systems becomes a challenging problem due to the infeasibility of centralized control. One promising strategy is to control only the shape of the system instead of the precise relative positions of the robots [1].

关键词： Multipurpose robots

A recursive least squares algorithm with ?1 regularization for sparse representation

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Science China(Information Sciences) 2023年第2期66卷 281-282页

作者： Di LIU Simone BALDI Quan LIU wenwu yu School of Cyber Science and Engineering Southeast University School of Computation Information and Technology Technical University of Munich School of Mathematics Center for Mobile Communication and Security Southeast University School of Artificial Intelligence Southeast University

Sparse representation aims to identify a few basic elements in a signal, so as to use a combination of such elements to reconstruct the original signal. The ?1-norm has been widely applied in sparse representation, either when processing batches of data offline, or online as in adaptive filtering [1–3]. Representative algorithms for online sparse representation include zero-attracting LMS(ZA-LMS) [4],?1-RLS [5], ?1-RRLS [6], zero-attracting RLS(ZA-RLS) [7],

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2016—2021年浦城县华支睾吸虫病流行现状分析

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寄生虫病与感染性疾病 2024年第1期22卷 31-34页

作者：余文武祖晓峰郑丽萍徐居俊浦城县疾病预防控制中心福建浦城353400 浦城县富岭卫生院福建浦城353416

目的了解浦城县人群华支睾吸虫的流行现状与防治效果,为本地区华支睾吸虫病的综合防治和传播控制提供依据。方法2016—2021年浦城县根据《全国肝吸虫病和土源性线虫病监测方案》要求,按浦城县地理方位划分东、南、西、北、中5个片区,每... 详细信息

目的了解浦城县人群华支睾吸虫的流行现状与防治效果,为本地区华支睾吸虫病的综合防治和传播控制提供依据。方法2016—2021年浦城县根据《全国肝吸虫病和土源性线虫病监测方案》要求,按浦城县地理方位划分东、南、西、北、中5个片区,每个片区随机抽取1个乡镇的1个村的人群作为调查对象。每个村采集每个3周岁以上居民粪便30g,全县每年共监测1000人。采用改良加藤氏厚涂片法(Kato-Kata)(1份2检)镜检虫卵。各调查点每年度检测各类淡水鱼类虾,取鱼部肌肉进行压片镜检。各调查点每年度随机收集野外狗粪或猫粪,以水洗沉淀法检测虫卵。每年在受检人群中随机抽查150人,进行华支睾吸虫病相关知识的问卷调查,并计算得分与知晓率(及格率)。率的比较采用卡方趋势检验,以P<0.05为差异有统计学意义。结果2016—2021年共调查6187人,华支睾吸虫感染者25人,感染率为0.40%。各年度感染率分别为0.95%、0.40%、0.43%、0.39%、0.35%和0.17%。检测3种淡水鱼类共646尾,囊蚴感染者375尾,感染率为58.05%。检测野外动物粪便标本共152份,检出华支睾吸虫卵8份,检出率为5.26%。收回居民有效问卷共900份,知晓率为47.89%(431/900)。2016—2021年知晓率分别为21.33%(32/150)、30.00%(45/150)、44.00%(66/150)、56.67%(85/150)、64.67%(97/150)和70.67%(106/150),呈现逐年上升趋势(χ_(趋势)^(2)=115.23,P<0.001)。结论浦城县人群华支睾吸虫感染率较低,防治效果显著。居民对华支睾吸虫病相关知识的知晓率低,淡水鱼类的囊蚴感染率较高,应加强宣传教育与防治工作。

关键词：华支睾吸虫流行现状分析浦城县

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急性缺血性脑卒中患者支架取栓术失败的影响因素及补救性Solitaire AB支架置入的可行性分析

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中国实用神经疾病杂志 2024年第4期27卷 425-430页

作者：孙喜凤张艳菊于文武张明月黄捷沧州市人民医院河北沧州061000

目的探究急性缺血性脑卒中(AIS)患者支架取栓术失败的影响因素及补救性Solitaire AB支架置入的可行性。方法以2018-10—2020-03沧州市人民医院160例AIS患者为研究对象,均给予支架取栓术治疗,根据手术疗效分为成功组及失败组,分析AIS... 详细信息

目的探究急性缺血性脑卒中(AIS)患者支架取栓术失败的影响因素及补救性Solitaire AB支架置入的可行性。方法以2018-10—2020-03沧州市人民医院160例AIS患者为研究对象,均给予支架取栓术治疗,根据手术疗效分为成功组及失败组,分析AIS患者支架取栓术失败的影响因素;根据术后是否置入Solitaire AB支架将失败组分为支架置入组及对照组,比较2组疗效、脑血管血流状况、神经营养因子水平及预后。结果 160例AIS患者中支架取栓术失败率为26.25%(42/160),失败组中年龄≥60岁、合并高脂血症、既往有脑卒中史、闭塞部位为颈内动脉的比例及入院时NIHSS评分高于成功组,发病至股动脉穿刺时间、穿刺至再通时间、发病至再通时间长于成功组,血栓切除次数多于成功组(P0.05)。支架置入组治疗后缺血面积小于对照组(P0.05)。结论颈内动脉闭塞、入院时NIHSS评分升高、发病至再通时间延长是AIS患者支架取栓术失败的危险因素,对支架取栓术失败患者给予补救性Solitaire AB支架置入治疗,可改善脑组织血流灌注,促进神经功能恢复。

关键词：急性缺血性脑卒中支架取栓术失败影响因素补救性Solitaire AB支架支架置入术

Eco-friendly biodegradable polyurethane based coating for antibacterial and antifouling performance

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Chinese Journal of Chemical Engineering 2023年第2期54卷 80-88页

作者： Abid Ali Bilal Ul Amin wenwu yu Taijiang Gui Weiwei Cong Kai Zhang Zheming Tong Jiankun Hu Xiaoli Zhan Qinghua Zhang College of Chemical and Biological Engineering Provincial Key Laboratory of Advanced Chemical Engineering Manufacture TechnologyZhejiang UniversityHangzhou 310027China Institute of Mold Technology Changzhou Vocational Institute of Mechatronic TechnologyChangzhou 213164China State Key Laboratory of Marine Coatings Marine Chemical Research Institute Co.LtdQingdao 266072China Quzhou Research Institute Zhejiang UniversityQuzhou 324000China

Biofouling, which comprises the absorption of proteins and the adhesion of bacteria to the surface of living entities, is a severe concern for the maritime sector since it ultimately leads to hydrodynamic drag,resulting in a higher increase in fuel consumption. As a result, polymer resins are crucial in the marine sector for anti-biofouling coatings. In this work, the poly(caprolactone-ethylene glycol-caprolactone)-p olyurethane(PECL-PU) are prepared through ε-caprolactone(CL), poly(ethylene glycol)(PEG), 4,4'-methylene bis(cyclohexyl isocyanate) and 1,4 butanediol. Our study demonstrate that the PECL-PU copolymer degraded in artificial seawater(5.21%), enzymatic solution(12.63%), and seawater(13.75%)due to the presence of PEG segments in the laboratory-based test under static condition. Because the addition of PEG segments are increased the polymer's amorphous area and decreased the crystallization of the polycaprolactone(PCL) in the copolymer, as demonstrated by differential scanning calorimetry, X-ray diffraction, and water contact angle studies. Therefore, the hydrolysis rates of PECL-PU were higher than the caprolactone-co-polyurethane(CL-PU). The antifouling test showed that PECL-PU3 copolymer had about 90.29% protein resistance, 85.2% Escherichia coli(E. coli) reduction and 94.61% marine diatom Navicula incerta reduction comparison to the control. We have developed an eco-friendly and inexpensive promising degradable polyurethane for reduction of bacterial biofilm, which can preserve the formation of biofouling on marine coating under practical sea conditions.

关键词： Caprolactone PEG segments Biodegradable polyurethane Biofouling Hydrolytic degradation