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Nonlinear Dynamics and Stability of Neural Networks with Delay-Time

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Journal of Systems Engineering and electronics 1992年第2期3卷 13-26页

作者： L. C. Jiao, member, IEEE, and Zheng Bao, Senior member, IEEECenter for Neural Networks and Institute of elec. Eng, Xidian University, Xian 710071, China Center for Neural Networks and Institute of elec. Eng Xidian University Xian 710071 China

In this paper we study the dynamic properties and stabilities of neural networks with delay-time (which includes the time-varying case) by differential inequalities and Lyapunov function approaches. The criteria of connective stability, robust stability, Lyapunov stability, asymptotic atability, exponential stability and Lagrange stability of neural networks with delay-time are established, and the results obtained are very useful for the design, implementation and application of adaptive learning neural networks.

关键词： Nonlinear dynamics Stability Neural network.

Accurate characterization of bubble mixing uniformity in a circular region using computational geometric theory

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Particuology 2024年第3期86卷 149-159页

作者： Hui Sun Jianxin Xu Shibo Wang Guangcheng Cai Hua Wang Wuliang Yin State Key Laboratory ofComplex Nonferrous Metal Resources Clean Utilization Kunming University ofScience and TechnologyKunming650093China bFaulty of Metallurgical and Energy Engineering Kunming University ofScience and TechnologyKunming650093China Faculty of Science Kunming University ofScience and TechnologyKunming650500China Department of elec.and electronic Engineering.University of Manchester ManchesterM139PL UK

The present study proposes a novel method based on the geometric theory for measuring the distribution of bubble swarms in the circular region of a direct-contact heat exchanger.It was determined that the mixing is uniform when the average distance between the bubble swarms in the unit circular region is approximately 0.9054,which is the standard reference value.The effect of sample size(i.e.,the number of bubbles)on mixing uniformity was investigated to determine the optimal sample size.It was verified that the metric's accuracy and stability were higher with a sample size of 155.Accordingly,it was proposed to increase the sample size by filling irregular bubbles using a segmentation method,which enabled a further accurate assessment of the mixing uniformity.The mixing uniformity of bubble swarms in the circular region and its maximum internal connection with the square region was accurately quantified.It was revealed that the relative average error increased by approximately 3.47% due to information loss.The proposed method was demonstrated to be rotationally invariant.The present study provided novel insights into evaluating mixing uniformity,which would guide enhanced heat transfer and the effective evaluation of the spatiotemporal characteristics of transient mixing in circular regions or the cross-sections of chemical transport pipelines.

关键词： Direct-contact heat exchanger Circular region Bubble swarm Distribution uniformity AD-Circle method

Joint alignment and steering to manage interference

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Digital Communications and Networks 2024年第2期10卷 429-438页

作者： Zhao Li Xiujuan Liang Yinghou Liu Jia Liu Zheng Yan School of Cyber Engineering Xidian UniversityXi'an710126China Technol.on Commun.Net.Lab. The 54th Research Inst.of China Elec.Technol.Group Corp.Shijiazhuang050081China School of Computer Science and Technology Xidian UniversityXi'an710126China The Department of Communications and Networking(Comnet) Aalto University02150EspooFinland

In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.However,when managing multiple disturbances from the same source,it may not be feasible to use existing IM methods such as Interference Alignment(IA)and Interference Steering(IS)exclusively.It is because with IA,the aligned interference becomes indistinguishable at its desired Receiver(Rx)under the cost constraint of Degrees-of-Freedom(DoF),while with IS,more transmit power will be consumed in the direct and repeated application of IS to each interference.To remedy these deficiencies,Interference Alignment Steering(IAS)is proposed by incorporating IA and IS and exploiting their advantages in IM.With IAS,the interfering Transmitter(Tx)first aligns one interference incurred by the transmission of one data stream to a one-dimensional subspace orthogonal to the desired transmission at the interfered Rx,and then the remaining interferences are treated as a whole and steered to the same subspace as the aligned interference.Moreover,two improved versions of IAS,i.e.,IAS with Full Adjustment at the Interfering Tx(IAS-FAIT)and Interference Steering and Alignment(ISA),are presented.The former considers the influence of IA on the interfering user-pair's performance.The orthogonality between the desired signals at the interfered Rx can be maintained by adjusting the spatial characteristics of all interferences and the aligned interference components,thus ensuring the Spectral Efficiency(SE)of the interfering communication pairs.Under ISA,the power cost for IS at the interfered Tx is minimized,hence improving SE performance of the interfered communication-pairs.Since the proposed methods are realized at the interfering and interfered Txs cooperatively,the expenses of IM are shared by both communication-pairs.Our in-depth simulation results show that joint use of IA and IS can effectively manage multiple disturbances

关键词： Interference Interference management Interference alignment Interference steering Spectral efficiency

A Parallel Computational Scheme on Hybrid Methods

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Journal of Systems Engineering and electronics 1994年第4期5卷 8-18页

作者： Zhao ShuangsuoDepartment of Mathematics, Lanzhou University, Lanzhou 730000Wang ChangyinInst. of Mech. & elec. Eng., Gansu University of Technology, Lanzhou 730050 Department of Mathematics Lanzhou University Lanzhou 730000 Inst. of Mech. & elec. Eng. Gansu University of Technology Lanzhou 730050

Based on the efficient hybrid methods for solving initial value problems of stiff ODEs, this paper derives a parallel scheme that can be used to solve the problems on parallel computers with N processors, and discusses the iteratively B-convergence of the Newton iterative process, finally, the paper provides some numberical results which show that the parallel scheme is highly efficient as N is not too large.

关键词： Hybrid methods Parallel computation Iteratively B-convergence.

Consumer-branch Connectivity Identification of Low Voltage Distribution Networks Based on Data-driven Approach

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Protection and Control of Modern Power Systems 2024年第4期9卷 69-82页

作者： Yongjun Zhang Yingqi Yi Wenyang Deng Siliang Liu Lai Zhou Kaidong Lin Yongzhi Cai the School of electric Power Engineering and Guangdong Key Laboratory of Clean Energy Technology South China Uni-versity of TechnologyGuangzhou 510641China the School of elec-tric Power Engineering South China University of TechnologyGuangzhou 510641China the Guangzhou Panyu vocational and technical college Guangzhou 511483China the Metrology Center Guangdong Power Company Grid Qingyuan 511500China

Accurate topological information is crucial in supporting the coordinated operational requirements of source-load-storage in low-voltage distribution networks.Comprehensive coverage of smart meters provides a database for low-voltage topology identification(LVTI).However,because of electricity theft,power line commu-nication crosstalk,and interruption of communication,the measurement data may be distorted.This can seriously affect the performance of LVTI methods.Thus,this paper defines hidden errors and proposes an LVTI method based on layer-by-layer stepwise regression.In the first step,a multi-linear regression model is developed for consumer-branch connectivity identification based on the energy conservation principle.In the second step,a significance factor based on the t-test is proposed to modify the identification results by considering the hidden errors.In the third step,the regression model and significance threshold parameters are iteratively updated layer by layer to improve the recall rate of the final identification results.Finally,simulations of a test system with 63 users are carried out,and the practical application results show that the proposed method can guarantee over 90%precision under the influence of hidden errors.

关键词： Data driven hidden error linear re-gression low voltage distribution network topology identification

Virtual Conductance Based Cascade Voltage Controller for VSCs in Islanded Operation Mode

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Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1704-1713页

作者： Francisco Jesús Matas-Díaz Manuel Barragán-Villarejo Juan Carlos Olives-Camps Juan Manuel Mauricio JoséMaría Maza-Ortega Department of elec‐trical Engineering Universidad de SevillaSeville 41092Spain

Voltage source converters have become the main enabler for the integration of distributed energy resources in microgrids.In the case of islanded operation,these devices normally set the amplitude and frequency of the network voltage by means of a cascade controller composed of an outer voltage control loop and an inner current control loop.Several strategies to compute the gains of both control loops have been proposed in the literature in order to obtain a fast and decoupled response of the voltages at the point of common coupling.This paper proposes an alternative and simple methodology based on the introduction of a virtual conductance in the classic cascade control.This strategy allows to design each control loop independently,obtaining a closed-loop response of a first-order system.In this way,the gains of each control loop are easily derived from the parameters of the LC coupling filter and the desired closed-loop time constants.Furthermore,a state observer is included in the controller to estimate the inductor current of the LC filter in order to reduce the number of required measurements.A laboratory testbed is used to validate and compare the proposed controller.The experimental results demonstrate the effectiveness of the proposal both in steady-state and transient regimes.

关键词： Voltage source converter microgrid cascade controller virtual conductance

THE LINEAR HOMOGENEOUS FLOW MODEL FOR TWO-PHASE FLOW INSTABILITY IN BOILING CHANNELS

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Journal of Hydrodynamics 2002年第2期14卷 106-111页

作者： Zhou Yun-long, Sun Bin, Gu Xin, Liang Qiang Northeast China Institute of electric Power Engineering, Jilin 132012, China Northeast China Inst. of elec. Jilin 132010 China

This paper presents liner homogeneous model describing two-phase flow instability. Dimensionless parameter η was derived by using the linear homogeneous model. Using parameter η the stability of a system could b... 详细信息

关键词： evaporated tubes steam-liquid two-phase flow homogeneous model

Edge-cloud collaborative intelligent production scheduling based on digital twin

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The Journal of China Universities of Posts and Telecommunications 2022年第2期29卷 108-120页

作者： Han Yifan Feng Tao Liu Xiaokai Xu Fangmin Zhao Chenglin School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China China National Tendering Center of Mach.&elec.Equipment Beijing 100142China Beijing Smart-Iiot Technology Co. Ltd.Beijing 100144China

With the application of various information technologies in smart manufacturing,new intelligent production mode puts forward higher demands for real-time and robustness of production scheduling.For the production scheduling problem in large-scale manufacturing environment,digital twin(DT)places high demand on data processing capability of the terminals.It requires both global prediction and real-time response abilities.In order to solve the above problem,a DT-based edge-cloud collaborative intelligent production scheduling(DTECCS)system was proposed,and the scheduling model and method were introduced.DT-based edge-cloud collaboration(ECC)can predict the production capacity of each workshop,reassemble customer orders,optimize the allocation of global manufacturing resources in the cloud,and carry out distributed scheduling on the edge-side to improve scheduling and tasks processing efficiency.In the production process,the DTECCS system adjusts scheduling strategies in real-time,responding to changes in production conditions and order fluctuations.Finally,simulation results show the effectiveness of DTECCS system.

关键词： edge-cloud collaboration(ECC) digital twin(DT) intelligent production scheduling real-time updated scheduling strategy

QUALITY CONTROL ON THE AUSTENITIC-BAINITIC DUCTILE IRON GEAR

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Journal of Wuhan University of Technology(Materials Science) 2000年第1期15卷 43-48页

作者：朱起凡 Xiangtan Inst. of Mach. and elec. China Mechanical Engineering Deparment Xiangtan Inst. of Mach. and Elec. Xiangtan 411101 Hunan China Wuhan Automot. Polytech. University China

By reasonable casting, spheroidizing, in- oculating and heattreating processes to control cupola met- allurgy and the lipuid ironchemical compositions, a new kind of austenitic-bainitic ductile ironwhich can substitute for 20CrMnTi carburizing steel is studied. Thegears made by the cost iron are high in quality, low in weight andthe production cost is greatly reduced. The mechnical proper- ties ofthe gear, including wear resistance, fatigue resis- tance, durabilityand others, can be greatly improved.

关键词： austenitic-bainitic iron gear