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Unveiling impacts of PMD on spectral modulations in PM-fiber-based ultrafast amplifiers

Chinese Optics Letters 2024年第12期22卷 57-62页

作者： Shang Wang Guanguang Gao Zhenhua Cong Zhaojun Liu Zhigang Zhao Key Laboratory of Laser&Infrared System Ministry of EducationShandong UniversityQingdao 266237China School of Information Science and Engineering Shandong UniversityQingdao 266237China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China Shandong Provincial Key Laboratory of Laser Technology and Application Shandong UniversityQingdao 266237China

In this work,polarization mode dispersion(PMD)in polarization-maintaining(PM)fibers,to the best of our knowledge,is first proposed and experimentally proved to be responsible for severe spectral modulations in ultrafast PM fiber amplifiers,the introduction of which can give reasonable explanation for the dense spectral ripples imposed on the spectra of amplified lasers from the commonly used all-PM-fiber or hybrid“PM-fiber+bulk crystal”amplifiers,including both high-power amplifiers with remarkable nonlinear effects(self-phase modulation,SPM)and even low-power amplifiers with negligible nonlinear effects.

关键词： spectral modulation polarization mode dispersion self-phase modulation polarization-maintaining fibers

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Research on Gene-Based Architecture Design Method of Command information system 4

Research on Gene-Based Architecture Design Method of Command...

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4th information Communication Technologies Conference, ICTC 2023

作者： Zhang, Zhaochen Mao, Xiaobin Huang, Songhua An, Haibo Science and Technology on Information Systems Engineering Laboratory Nanjing China

ISBN: (纸本)9781665462587

The concept of biological gene is transferred to the field of command information system architecture, and the concept of command information system architecture gene is proposed. For networked and intelligent systems, the command information system architecture gene reference models are established, including resource gene model and resource relationship gene model, and 7 types of resource operation modes and 6 types of resource relationship modes are described abstractly. On this basis, a gene-based intelligent command information system architecture design process is proposed. Finally, a typical case is used to verify the guiding role of the architecture design method in the intelligent system construction. © 2023 IEEE.

关键词： Genes

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A Phase-Dependent and EMG-Driven Variable Stiffness Control Strategy for Upper Limb Rehabilitation Robot

A Phase-Dependent and EMG-Driven Variable Stiffness Control ...

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2024 IEEE International Conference on Robotics and Biomimetics, ROBIO 2024

作者： Li, Pengcheng Guo, Shuxiang Li, Chunying Southern University of Technology and Science Department of Electronic and Electrical Engineering Shenzhen China Aerospace Center Hospital School of Life Science Key Laboratory of Convergence Medical Engineering System and Healthcare Technology Ministry of Industry and Information Technology Beijing Institute of Technology Beijing China

ISBN: (纸本)9781665481090

Bilateral training is a widely adopted approach in upper limb rehabilitation due to its effectiveness and ease of implementation. Variable stiffness actuators enhance this approach by facilitating compliant human-machine interaction, ensuring both comfort and safety. However, optimizing stiffness levels for individual subjects to maximize training effectiveness remains a significant challenge. The difficulty of different task phases varies across subjects, necessitating customized robotic assistance. This paper proposes an adaptive stiffness modulation strategy that leverages the cyclic nature of rehabilitation tasks. An adaptive frequency oscillator is employed for real-time phase detection, while a tuning rule, based on motion tracking error and muscular activation, dynamically adjusts stiffness levels. Experimental validation with two participants demonstrated that the proposed strategy effectively promotes affected arm motion and tailors assistance to the user's specific needs. © 2024 IEEE.

关键词： Human robot interaction

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Distributed Constrained Optimization with Uncoordinated Step Sizes: A Case Study on Ethylene Plant

Distributed Constrained Optimization with Uncoordinated Step...

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2024 China Automation Congress, CAC 2024

作者： Liu, Bing Li, Zhongmei Du, Wenli School of Information Science and Engineering East China University of Science and Technology Shanghai China Engineering Research Center of Process System Engineering Ministry of Education East China University of Science and Technology Shanghai China

ISBN: (纸本)9798350368604

This paper investigates an uncoordinated step sizes distributed optimization algorithm based on an undirected topology network structure, which can handle distributed optimization problems with inequality constraints and heterogeneity (losing the global clock) by only communicating with neighboring nodes. Firstly, an "Adapt-Then-Combine Distributed Inexact Gradient tracking subject to Inequality Constraints (ATC-DIGing-IC)" algorithm is proposed for μ-strongly convex and l-smooth objective functions. Using the "Adapt-Then-Combine (ATC)" framework and the gradient information tracking structure, the flexibility and fastness of the algorithm can be guaranteed under the uncoordinated step size. Then, a parameter projection technique is introduced to handle the inequality constraints without introducing additional auxiliary variables. Subsequently, the convergence results of the algorithm and the bounds on the uncoordinated step sizes are theoretically analyzed. Finally, the algorithm is applied to a plant-wide separation production process of an ethylene plant, and the experimental results show that the proposed algorithm requires a shorter optimization time than the existing methods. © 2024 IEEE.

关键词： Constrained optimization

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Discovering Cohesive Temporal Subgraphs with Temporal Density Aware Exploration

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Journal of Computer science & technology 2022年第5期37卷 1068-1085页

作者： Chun-Xue Zhu Long-Long Lin Ping-Peng Yuan Hai Jin National Engineering Research Center for Big Data Technology and System Huazhong University of Science and TechnologyWuhan 430074China Service Computing Technology and System Laboratory Huazhong University of Science and TechnologyWuhan 430074China Cluster and Grid Computing Laboratory Huazhong University of Science and TechnologyWuhan 430074China School of Computer Science and Technology Huazhong University of Science and TechnologyWuhan 430074China

Real-world networks,such as social networks,cryptocurrency networks,and e-commerce networks,always have occurrence time of interactions between *** networks are typically modeled as temporal *** cohesive subgraphs from temporal graphs is practical and essential in numerous data mining applications,since mining cohesive subgraphs gets insights into the time-varying nature of temporal ***,existing studies on mining cohesive subgraphs,such as Densest-Exact and k-truss,are mainly tailored for static graphs(whose edges have no temporal information).Therefore,those cohesive subgraph models cannot indicate both the temporal and the structural characteristics of *** this end,we explore the model of cohesive temporal subgraphs by incorporating both the evolving and the structural characteristics of temporal ***,the volume of time intervals in a temporal network is *** a result,the time complexity of mining temporal cohesive subgraphs is *** efficiently address the problem,we first mine the temporal density distribution of temporal *** by the distribution,we can safely prune many unqualified time intervals with the linear time ***,the remaining time intervals where cohesive temporal subgraphs fall in are examined using the greedy *** results of the experiments on nine real-world temporal graphs indicate that our model outperforms state-of-the-art solutions in efficiency and ***,our model only takes less than two minutes on a million-vertex DBLP and has the highest overall average ranking in EDB and TC metrics.

关键词： temporal network temporal feature distribution cohesive subgraph convex property

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Theoretical analysis of the elastic Kelvin-Helmholtz instability in explosive weldings

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Defence technology（防务技术） 2024年第2期32卷 521-528页

作者： Yuanbo Sun Jianning Gou Cheng Wang Qiang Zhou Rui Liu Pengwan Chen Tonghui Yang Xiang Zhao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Beijing HIWING Scientific and Technological Information Institute Beijing100084China School of Aerospace Engineering Tsinghua UniversityBeijing100084China

By considering the joint effects of the Kelvin-Helmholtz(KH) and Rayleigh-Taylor(RT) instabilities, this paper presents an interpretation of the wavy patterns that occur in explosive welding. It is assumed that the elasticity of the material at the interface effectively determines the wavelength, because explosive welding is basically a solid-state welding process. To this end, an analytical model of elastic hydrodynamic instabilities is proposed, and the most unstable mode is selected in the solid phase. Similar approaches have been widely used to study the interfacial behavior of solid metals in high-energy-density physics. By comparing the experimental and theoretical results, it is concluded that thermal softening,which significantly reduces the shear modulus, is necessary and sufficient for successful welding. The thermal softening is verified by theoretical analysis of the increase in temperature due to the impacting and sliding of the flyer and base plates, and some experimental observations are qualitatively *** summary, the combined effect of the KH and RT instabilities in solids determines the wavy morphology, and our theoretical results are in good qualitative agreement with experimental and numerical observations.

关键词： Explosive welding Hydrodynamic instabilities Elasticity

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Remote sensing image encryption algorithm based on novel hyperchaos and an elliptic curve cryptosystem

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Chinese Physics B 2024年第5期33卷 292-304页

作者：田婧希金松昌张晓强杨绍武史殿习 School of Computer Science National University of Defense TechnologyChangsha 410003China Intelligent Game and Decision Laboratory (IGDL) Beijing 100091China School of Information and Control Engineering China University of Mining and TechnologyXuzhou 221116China

Remote sensing images carry crucial ground information,often involving the spatial distribution and spatiotemporal changes of surface *** safeguard this sensitive data,image encryption technology is *** this paper,a novel Fibonacci sine exponential map is designed,the hyperchaotic performance of which is particularly suitable for image encryption *** encryption algorithm tailored for handling the multi-band attributes of remote sensing images is *** algorithm combines a three-dimensional synchronized scrambled diffusion operation with chaos to efficiently encrypt multiple ***,the keys are processed using an elliptic curve cryptosystem,eliminating the need for an additional channel to transmit the keys,thus enhancing *** results and algorithm analysis demonstrate that the algorithm offers strong security and high efficiency,making it suitable for remote sensing image encryption tasks.

关键词： hyperchaotic system elliptic curve cryptosystem(ECC) 3D synchronous scrambled diffusion remote sensing image unmanned aerial vehicle(UAV)

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Bifurcation analysis of a diffusive radio-dependent model with spatial memory

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International Journal of Biomathematics 2024年第8期17卷 309-347页

作者： Qi An Xingyu Guo Xuebing Zhang College of Mathematics and Statistics Nanjing University of Information Science and Technology Nanjing 210044 P.R.China Jiangsu International Joint Laboratory on System Modeling and Data Analysis Center for Applied Mathematics of Jiangsu Province Nanjing University of Information Science and Technology Nanjing 210044 P.R.China

This is an Open Access article published by World Scientific Publishing *** is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0(CC BY-NC-ND)License,which permits use,distribution and reproduction,provided that the original work is properly cited,the use is non-commercial and no modifications or adaptations are *** cognitive abilities of animals,such as memory,have a significant impact on their movement in *** this paper,we consider a radio-dependent model with memorybased diffusion under the conditions of Neumann *** stability of a positive equilibrium and the existence of the Turing-Hopf bifurcation induced by memory diffusion and memory delay are carried out in ***,our findings indicate that with a relatively short average memory period,the large memory diffusion can stabilize an otherwise unstable *** addition,the third-order truncated normal form for the Turing-Hopf bifurcation restricted to the central manifold is derived,which can reveal the generation of some steady-state and time-periodic solutions with spatial *** coefficients within the normal form are systematically determined through matrix operations,and these results can also be applied to other models with memory ***,leveraging the theoretical findings,we elucidated the intricate spatial-temporal dynamics and their associated parameter scopes caused by Turing-Hopf bifurcation through numerical simulations.

关键词： Spatial memory normal form Turing-Hopf bifurcation spatio-temporal patterns periodic solutions

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Event-Triggered Cooperative Tracking Control of Multiagent systems with a Dynamic Leader via Approximate Dynamic Programming

IEEE Transactions on Artificial Intelligence

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IEEE Transactions on Artificial Intelligence 2024年第6期5卷 2752-2765页

作者： Fu, Hao He, Haodong Chen, Yang Wuhan University of Science and Technology Hubei Province Key Laboratory of Intelligent Information Processing and Real-time Industrial System The School of Computer Science and Technology Wuhan430081 China Wuhan University of Science and Technology Eng. Res. Center for Metallurgical Automation and Measurement Technology of Ministry of Education Wuhan430081 China

This article investigates the optimal cooperative tracking control problem for unknown nonlinear multiagent systems with a real dynamic leader and uncertainties. Its main difficulty lies in eliminating effect of the unmatched uncertainty and noncooperation in the event-triggered manner. To overcome this difficulty, a distributed robust event-triggered control algorithm is developed with the aid of a disturbance observer and robust approximate dynamic programming (ADP). Specifically, this problem is converted into a cooperative multiplayer game for the distributed auxiliary systems employing observer-based feedforward compensation, which contributes to reducing conservatism;via an adaptive event-triggered mechanism and a new weight tuning law, a distributed robust ADP approach is proposed with hope to obviate judging the existence of the saddle point beforehand. Moreover, the local neighbor tracking error and the weight estimation error are demonstrated to be uniformly ultimately bounded by means of Lyapunov stability theory. We also prove that Zeno behavior is excluded. A comparative simulation example for multiquadrotor systems is carried out to verify the effectiveness and superiority of our algorithm. © 2020 IEEE.

关键词： Dynamic programming

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H∞ fault-tolerant fuzzy intermittent control for nonlinear hyperbolic PDE systems with multiple delays and actuator failures

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ISA Transactions 2025年 156卷 39-60页

作者： Zhang, Xu Gao, Xuan Wang, Zi-Peng Luo, Biao Han, Ke-Zhen Yan, Xue-Hua School of Automation Central South University Changsha410083 China School of Electrical Engineering University of Jinan Jinan250022 China School of Information Science and Technology Beijing Laboratory of Smart Environmental Protection Beijing Key Laboratory of Computational Intelligence and Intelligent System and Beijing Institute of Artificial Intelligence Beijing University of Technology Beijing100124 China

This study presents an H∞ fault-tolerant fuzzy intermittent control approach for the nonlinear hyperbolic partial differential equation (PDE) systems with multiple delays and actuator failures (MDAFs). Firstly, the nonlinear hyperbolic PDE systems with MDAFs are characterized by the Takagi–Sugeno (T–S) fuzzy delayed hyperbolic PDE model. Next, by employing the Lyapunov direct method, this paper demonstrates the robust exponential stability using spatial linear matrix inequalities (SLMIs) based on a new switching Lyapunov functional (LF). Furthermore, the H∞ fault-tolerant fuzzy intermittent control issue for nonlinear hyperbolic PDE systems with MDAFs is transformed into the LMI feasibility problem to deal with the SLMIs. Lastly, the feasibility of the constructed control strategy is demonstrated by two illustrative examples. © 2024 International Society of Automation

关键词： Lyapunov functions

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