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Journal of Automation and Intelligence 2023年第1期2卷 42-50页

作者： Xiucai Huang Zhengguo li frank l.lewis Chongqing Key laboratory of Intelligent Unmanned Systems School of AutomationChongqing UniversityChongqing400044China The SRO Department Institute for Infocomm Research138632Singapore The University of Texas at Arlington ArlingtonTX 76118USA

In this paper,the fault-tolerant formation control(FTFC)problem is investigated for a group of uncertain nonholonomic mobile robots with limited communication ranges and unpredicted actuator faults,where the communication between the robots is in a directed one-to-one *** order to guarantee the connectivity preservation and collision avoidance among the robots,some properly chosen performance functions are incorporated into the controller to per-assign the asymmetrical bounds for relative distance and bearing angle between each pair of adjacent mobile ***,the resultant control scheme remains at a costeffective level because its design does not use any velocity information from neighbors,any prior knowledge of system nonlinearities or any nonlinear approximator to account for them despite the presence of modeling uncertainties,unknown external disturbances,and unexpected actuator ***,each follower is derived to track the leader with the tracking errors regarding relative distance and bearing angle subject to prescribed transient and steady-state performance guarantees,***,all the closed-loop signals are ensured to be ultimately uniformly ***,a numerical example is simulated to verify the effectiveness of this methodology.

关键词： Fault-tolerant formation control Nonholonomic mobile robot Connectivity preservation Collision avoidance

Sampled-data control through model-free reinforcement learning with effective experience replay

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Journal of Automation and Intelligence 2023年第1期2卷 20-30页

作者： Bo Xiao H.K.lam Xiaojie Su Ziwei Wang frank P.-W.lo Shihong Chen Eric yeatman Department of Electrical and Electronic Engineering Imperial College LondonLondon SW72AZUK Department of Engineering King’s College LondonLondon WC2B 4BGUK Department of Automation Chongqing UniversityShapingba DistrictChong QingChina School of Engineering Lancaster UniversityLA14YWUK Hamlyn Centre Imperial College LondonLondon SW72AZUK

Reinforcement learning(Rl)based control algorithms can learn the control strategies for nonlinear and uncertain environment during interacting with *** by the rewards generated by environment,a Rl agent can learn the control strategy directly in a model-free way instead of investigating the dynamic model of the *** the paper,we propose the sampled-data Rl control strategy to reduce the computational *** the sampled-data control strategy,the whole control system is of a hybrid structure,in which the plant is of continuous structure while the controller(Rl agent)adopts a discrete *** that the continuous states of the plant will be the input of the agent,the state–action value function is approximated by the fully connected feed-forward neural networks(FCFFNN).Instead of learning the controller at every step during the interaction with the environment,the learning and acting stages are decoupled to learn the control strategy more effectively through experience *** the acting stage,the most effective experience obtained during the interaction with the environment will be stored and during the learning stage,the stored experience will be replayed to customized times,which helps enhance the experience replay *** effectiveness of proposed approach will be verified by simulation examples.

关键词： Reinforcement learning Neural networks Sampled-data control Model-free Effective experience replay

Facile li-Al layered double hydroxide films on Al alloy for enhanced hydrophobicity, anti-biofouling and anti-corrosion performance

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Journal of Materials Science & Technology 2021年第20期79卷 230-242页

作者： Ji li Tianci yuan Chengliang Zhou Bo Chen yi Shuai Dawang Wu Dongchu Chen Xiaohu luo y.frank Cheng yali liu State Key laboratory for Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha410082China Department of Mechanical and Manufacturing Engineering University of CalgaryCalgaryAlbertaT2N 1N4Canada School of Chemistry and Chemical Engineering Qiannan Normal University for NationalitiesDuyun558000China College of Mechanical Engineering and Applied Electronics Technology Beijing University of TechnologyBeijing100124China School of Material Science and Energy Engineering Foshan UniversityFoshan528000China

In this work,lithium(li)-aluminum(Al)layered double hydroxide(lDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were prepared on 6N01 Al alloy by a facile,in-situ growth method with enhanced hydrophobicity,anti-biofouling and anti-corrosion *** preparation is low energy consumptive and environment friendly,relying on self-assembly at ambient *** structure,molecular weight and functional groups of the synthesized AOA acid were characterized by NMR spectrometer,ESI-MS spectrometer and Fourier transform infrared(FT-IR)*** the compositions,structure and morphology of the films were characterized by Fourier transform infrared(FT-IR)spectroscopy,glancing-angle X-ray diffraction(GA-XRD),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM)and energy-dispersive x-ray spectrum(EDS).Water contact angle measurements(CA)and atomic force microscopy(AFM)characterization show that the films possess a micro/nanostructure with an improved *** test,neutral salt tests(NSS)and electrochemical impedance spectroscopy(EIS)conducted in 3.5 wt.%NaCl solutions demonstrate the improved corrosion resistance of the films over bare Al ***,the films also possess an excellent anti-bacterial property toEscherichia coli,Bacillus subtilis and sulfate-reducing bacteria.

关键词： li-Al layered double hydroxides Anti-biofouling Hydrophobicity Anti-bacterial Anti-corrosion

Templating core-shell particles using metal ion-chelating biosurfactants

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Particuology 2022年第5期20卷 145-152页

作者： Ching-Min yeh Thomas Jarrett yuan Gao Chun-Xia Zhao Andrew Whittaker frank Sainsbury Alison l.White Australian Institute of Bioengineering and Nanotechnology The University of QueenslandSt.LuciaQueensland4072Australia ARC Centre of Excellence in Convergent Bio-Nano Science and Technology The University of QueenslandSt Lucia4072Australia CSIRO Probing Biosystems Future Science Platform BrisbaneAustralia Centre for Cell Factories and Biopolymers Griffith Institute for Drug DiscoveryGriffith UniversityBrisbaneQLD4111 Australia

Designer biosurfactants can be used to stabilise and functionalise *** particularly promising use is the stabilisation of oil-in-water emulsions,enabling fine tuning physical,chemical and biological surface *** ability of emulsion systems to carry high payloads makes them attractive for applications in medicine,food and fragrances,and ***,they have limited long-term *** we sought to use the metal ion-chelating ability of the biosurfactant peptide,AM1,to precipitate the formation of a gold metal shell on AM1-stabilised emulsions by electroless *** found that replacing the commonly used zinc(Ⅱ)with palladium(Ⅱ)for coordination by histidine residues of adjacent AM1 peptides produced interfacial films that maintained elasticity at acidic *** NMR suggested a coordination mechanism independent of the imidazole ring of the *** of emulsions at low pH enabled the deposition of a gold shell,albeit by an unexpected *** propose that gold nanoparticles forming in bulk are adsorbed onto the peptide-stabilised interface,accumulating into a particulate *** resulting one-step method for nanoparticle precipitation and shell formation will be useful for the creation of biocompatible core-shell particles for applications where large payloads of hydrophobic active compounds require stability over long time periods.

关键词： Biosurfactants Emulsion Core-shell particles Electroless plating Histidine Interfacial elasticity

Inheritance of marsh spot disease resistance in cranberry common bean(Phaseolus vulgaris l.)

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The Crop Journal 2022年第2期10卷 456-467页

作者： Bosen Jia Robert l.Conner Nadeem Khan Anfu Hou Xuhua Xia frank M.you Ottawa Research and Development Centre Agriculture and Agri-Food CanadaOttawaOntario K1A 0C6Canada Department of Biology University of OttawaOttawaOntario K1N 6N5Canada Morden Research and Development Centre Agriculture and Agri-Food CanadaMordenManitoba R6M 1Y5Canada

Common bean(Phaseolus vulgaris) is an annual legume crop that is grown worldwide for its edible dry seeds and tender pods. Marsh spot(MS) of the seeds is a physio-genic stress disease affecting seed quality in beans. Studies have suggested that this disease involves a nutritional disorder caused by manganese deficiency, but the inheritance of resistance to this disease has not been reported. A biparental genetic population composed of 138 recombinant inbred lines(RIls) was developed from a cross between an MS resistant cultivar ‘Cran09’ and an MS susceptible cultivar ‘Messina’. The 138 RIls and their two parents were evaluated for MS resistance during five consecutive years from 2015 to 2019 in sandy and heavy clay soils in Morden, Manitoba, Canada. The MS incidence(MSI) and the MS resistance index(MSRI) representing disease severity were shown to be both highly correlated heritable traits that had high broad-sense heritability values(H;) of 86.5% and 83.2%, respectively. No significant differences for MSI and MSRI were observed between the two soil types in all five-(MSI) or four-year(MSRI) data collection, but significant correlations among years were observed despite MS resistance was moderately affected by year. The MSIs and MSRIs displayed a right-skewed distribution, indicating a mixed genetic model involving a few major genes and polygenes. Using the joint segregation analysis method, the same four major genes with additive-epistasis effects showed the best fit for both traits, explaining 84.4% and85.3% of the phenotypic variance for MSI and MSRI, respectively. For both traits, the M1, M2, M3 and m4 acted as the favorable(resistant) alleles for the four genes where M and m represent two alleles of each gene. However, due to epistatic effects, only the individuals of the M1 M2 M3 M4 haplotype appeared to be highly resistant, whereas those of the m1 m2 m3 M4 haplotype were the most susceptible. The m4 allele significantly suppressed the additive effects of M1 M

关键词： Common bean Cranberry bean Marsh spot Resistance Recombinant inbred line(RIl) Joint segregation analysis Major gene Polygene

Guest Editorial for Special Issue on Extensions of Reinforcement learning and Adaptive Control

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IEEE/CAA Journal of Automatica Sinica 2014年第3期1卷 225-226页

作者： frank l.lewis Warren Dixon Zhongsheng Hou Tansel yucelen Institute of Measurement&Control PE TexasU.K IEEE Control Systems Society(CSS) Operations for the Executive Committee of the IEEE CSS Board of Governors the Harbin Institute of Technology the Advanced Control Systems lab Beijing Jiaotong University the Department of Automatic Control in School of Electronic and Information Engineering Beijing Jiaotong University Mechanical and Aerospace Engineering Department at the Missouri University of Science and Technology Advanced Systems Research laboratory at the Missouri University of Science and Technology

ADAPTIVE control is a proven method for learning feedback controllers for systems with unknown dynamic models,exogenous disturbances,nonzero setpoints,and unmodeled *** control has been applied for years in process co... 详细信息

关键词： Special issues and sections learning (artificial intelligence) Adaptive control Feedback

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尾座式无人飞行器鲁棒容错编队控制

航空学报 2021年第2期42卷 297-305页

作者：刘德元刘昊 frank l lEWIS 北京航空航天大学宇航学院北京100083 德克萨斯大学阿灵顿分校德克萨斯大学阿灵顿研究所沃斯堡76118

针对尾座式无人飞行器编队在执行器故障、严重的非线性和耦合性、参数不确定性、外界扰动等影响下的容错控制问题进行了研究。提出了一种鲁棒容错编队控制方法来实现一群尾座式无人飞行器在执行器故障情况下的期望编队飞行。所构建的控... 详细信息

针对尾座式无人飞行器编队在执行器故障、严重的非线性和耦合性、参数不确定性、外界扰动等影响下的容错控制问题进行了研究。提出了一种鲁棒容错编队控制方法来实现一群尾座式无人飞行器在执行器故障情况下的期望编队飞行。所构建的控制器由2部分组成:标称控制器和干扰补偿控制器。设计标称控制器使系统实现期望的控制性能,利用干扰补偿控制器抑制多种不确定性和执行器故障的影响。通过理论分析证明了系统的鲁棒稳定性,并通过数值仿真验证了算法的有效性。

关键词：编队控制容错控制尾座式无人飞行器鲁棒控制不确定性系统

Effect of hot rolling on microstructure and properties of the ZEK100 alloy

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Journal of Magnesium and Alloys 2019年第1期7卷 27-37页

作者： Amjad Javaid frank Czerwinski CanmetMATERIAlS 183 Longwood Road SouthHamiltonOntario L8P 0A5Canada

Attempts to expand manufacturing capabilities of magnesium-based sheet materials are *** as-cast ZEK100(Mg-1.2Zn-0.35Zr-0.17Nd,in wt%)magnesium alloy was subjected to hot rolling at temperatures from 350℃to 450℃using the laboratory 50 ton reversible mill with preheated rolls to manufacture the 1.5-1.7 mm thick *** rolling temperature affected the sheet properties and an increase in the rolling temperature from 250 to 450℃caused reduction of tensile strength from 257 to 228 MPa ac-companied by a reduction in tensile yield stress from 237 to 185 *** the same time,the alloy elongation increased from 17 to 21%.For the same rolling temperature range,the compressive strength reduced from 418 to 351 *** post-rolling annealing at 450℃led to reduction of both tensile and compressive properties with the largest changes corresponding to the rolling temperature of 350°*** correlation between the alloy grain size after rolling and the sheet properties was established where a reduction in grain size was accompanied by an increase of both the tensile/compressive strength and yield *** on Hall-Petch relationship and an average grain size the correlation developed in this study may be used as the prediction model for properties of the hot rolled magnesium *** results are discussed in terms of recent developments in magnesium sheet alloys and the vital role played in this process by rare earth elements.

关键词： Magnesium alloys Hot deformation Microstructure Rare earths Sheet rolling

Discrete-time dynamic graphical games:model-free reinforcement learning solution

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Control Theory and Technology 2015年第1期13卷 55-69页

作者： Mohammed I.ABOUHEAF frank l.lEWIS Magdi S.MAHMOUD Dariusz G.MIKUlSKI Systems Engineering Department King Fahd University of Petroleum & Mineral UTA Research Institute University of Texas at ArlingtonFort Worth Texas U.S.A. State Key laboratory of Synthetical Automation for Process Industries Northeastern University Ground Vehicle Robotics (GVR) U.S. Army TARDEC Warren MI U.S.A.

This paper introduces a model-free reinforcement learning technique that is used to solve a class of dynamic games known as dynamic graphical games. The graphical game results from to make all the agents synchronize to the state of a command multi-agent dynamical systems, where pinning control is used generator or a leader agent. Novel coupled Bellman equations and Hamiltonian functions are developed for the dynamic graphical games. The Hamiltonian mechanics are used to derive the necessary conditions for optimality. The solution for the dynamic graphical game is given in terms of the solution to a set of coupled Hamilton-Jacobi-Bellman equations developed herein. Nash equilibrium solution for the graphical game is given in terms of the solution to the underlying coupled Hamilton-Jacobi-Bellman equations. An online model-free policy iteration algorithm is developed to learn the Nash solution for the dynamic graphical game. This algorithm does not require any knowledge of the agents＇ dynamics. A proof of convergence for this multi-agent learning algorithm is given under mild assumption about the inter-connectivity properties of the graph. A gradient descent technique with critic network structures is used to implement the policy iteration algorithm to solve the graphical game online in real-time.

关键词： Dynamic graphical games Nash equilibrium discrete mechanics optimal control model-free reinforcementlearning policy iteration

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TeV astronomy

Frontiers of physics 2013年第6期8卷 714-747页

作者： frank M. Rieger Max-Planck-Institut fiir Kernphysik P.O. Box 103980 69029 Heidelberg Germany Institut de Ciencies de l'Espai (IEEC-CSIC) Campus UAB Torte C5 08193 Bellaterra Spain Dublin Institute for Advanced Studies 31 Fitzwilliam Place Dublin 2 Ireland European Associated laboratory for Gamma-Ray Astronomy jointly supported by CNRS and MPG

With the successful realization of the current-generation of ground-based detectors, TeV Astronomy has entered into a new era. We review recent advances in VHE astronomy, focusing on the potential of Imaging Atmospheric Cherenkov Telescopes （IACTs）, and highlight astrophysical implications of the results obtained within recent years.

关键词： TeV astronomy gamma-rays Cherenkov telescopes high-energy astrophysics