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A memristor-based circuit design for generalization and differentiation on Pavlov associative memory

NEUROCOMPUTING 2020年 389卷 18-26页

作者： Shang, Meijia Wang, Xiaoping Huazhong Univ Sci & Technol Sch Artificial Intelligence & Automat Key Lab Image Proc & Intelligent Control Wuhan 430074 Peoples R China

The traditional Pavlov associative memory contains the process of learning and forgetting, which correspond to the reinforcement and extinction in classical conditional reflex respectively. In fact, besides reinforcement and extinction, classical conditional reflex also contains generalization and differentiation. In this paper, a memristor-based circuit is designed to implement generalization and differentiation based on Pavlov associative memory. This circuit can respond to one kind of conditional stimulus after the initial learning, then when another similar stimulus is applied to the circuit, the circuit responds similarily, this is the phenomenon of generalization. To make the circuit be sufficiently cognizant of these two similar stimuli and ultimately distinguish them, a special training method, which selectively reinforces one stimulus while inhibits another similar stimulus, is used to train the whole circuit. As a result, when these two similar stimuli are applied to the circuit separately again, it can respond to them differently. This is the phenomenon of differentiation. Finally, the correctness of implementing these functions described above are demonstrated by simulation results in PSPICE. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Memristor Generalization Differentiation Pavlov associative memory Circuit design

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Predefined-Time Secondary control for DC Microgrid

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2022年第12期69卷 13504-13513页

作者： Zhang, Yu Wang, Yan-Wu Xiao, Jiang-Wen Liu, Xiao-Kang Huazhong Univ Sci & Technol Sch Artificial Intelligence & Automat Key Lab Image Proc & Intelligent Control Wuhan 430074 Peoples R China

DC microgrid as a microscale power system has drawn growing attention for its various applications, which calls for good power quality, proper power sharing, and fast response property. However, the existing researches are not yet able to achieve the purpose in a predefined time. In this article, a new predefined-time secondary controller is proposed for DC microgrid to realize the objectives of both voltage regulation and current sharing among DGs within a predefined time. The controller is designed by employing a sign function and a K-1 function and by defining a new composite error, which does not need to sample the voltage of DC bus or the current of neighbors, but only the local current and voltage. The upper bound of the convergence time of both the voltage and current in the DC microgrid is just related to one parameter which can be predefined and is independent of initial error. The effectiveness of the proposed controller is verified by multiple simulations and experiments built on MATlab/Simulink and a hardware-in-the-loop experimental platform. The conducted simulations and experiments include several typical scenarios together with a comparison, which illustrate the advantages of the proposed controller such as fast convergence rate and small overshoot.

关键词： Current sharing DC microgrid predefined-time control stability analysis voltage regulation

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Carrier-overlapping PWM-based hybrid current control strategy applied to two-stage grid-connected PV inverter

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IET POWER ELECTRONICS 2018年第1期11卷 182-191页

作者： Liu, Jiang Cheng, Shanmei Shen, Anwen Huazhong Univ Sci & Technol Sch Automat Key Lab Educ Minist Image Proc & Intelligent Control Wuhan Hubei Peoples R China

For a wide dc input voltage range of photovoltaic (PV) array, a two-stage grid-connected inverter that allows input voltage regulation is required. This study proposes a topology with time-sharing synchronous modulation in which energy transmission paths, wheeling branches and switching losses for high-frequency switches are optimised to achieve efficiency improvement. The small-signal model of proposed topology is analysed in detail. A hybrid current control strategy based on frequency-amplitude domain analysis is presented. To solve further transitional problem on boost-buck mode switching, the controller uses a carrier-overlapping pulse-width modulation (PWM)-based generator. Then, the effectiveness of the proposed topology and the control strategy under different experimental conditions are verified. Experimental results indicate hybrid current control strategy promotes current waveform quality and the burrs and oscillations in transition between buck mode and boost mode can be reduced.

关键词： PWM invertors power grids electric current control voltage control frequency-domain analysis photovoltaic power systems two-stage grid-connected PV inverter hybrid current control photovoltaic array voltage regulation time-sharing synchronous modulation energy transmission paths switching loss high-frequency switches small-signal model frequency-amplitude domain analysis boost-buck mode switching carrier-overlapping pulse-width modulation-based generator current waveform quality

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Fault prediction for nonlinear stochastic system with incipient faults based on particle filter and nonlinear regression

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ISA TRANSACTIONS 2017年 68卷 327-334页

作者： Ding, Bo Fang, Huajing Huazhong Univ Sci & Technol Sch Automat Key Lab Image Proc & Intelligent Control Minist Educ Wuhan 430074 Peoples R China

This paper is concerned with the fault prediction for the nonlinear stochastic system with incipient faults. Based on the particle filter and the reasonable assumption about the incipient faults, the modified fault estimation algorithm is proposed, and the system state is estimated simultaneously. According to the modified fault estimation, an intuitive fault detection strategy is introduced. Once each of the incipient fault is detected, the parameters of which are identified by a nonlinear regression method. Then, based on the estimated parameters, the future fault signal can be predicted. Finally, the effectiveness of the proposed method is verified by the simulations of the Three-tank system. (C) 2017 ISA. Published by Elsevier Ltd. All rights reserved.

关键词： Fault detection Fault prediction Nonlinear stochastic system Incipient fault Particle filter Nonlinear regression

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The computational power of tissue-like P systems with promoters

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THEORETICAL COMPUTER SCIENCE 2016年第0期641卷 43-52页

作者： Song, Bosheng Pan, Linqiang Huazhong Univ Sci & Technol Sch Automat Key Lab Image Informat Proc & Intelligent Control Wuhan 430074 Hubei Peoples R China

Tissue P systems are distributed parallel computing models inspired by the structure of tissue and the way of communicating substances between two cells or between a cell and the environment. In this work, we consider a variant of tissue P systems, called tissue P systems with promoters, where the application of rules is regulated by promoters. The computational power of such P systems is investigated. Specifically, it is proved that such P systems using only antiport rules of length 2 or using only symport rules of length 1 are able to compute only finite sets of non-negative integers. However, such P systems with one cell and using antiport rules of length 2 and symport rules of length 1 or only using symport rules of length 2 are Turing universal. Moreover, a uniform solution to the SAT problem is provided by tissue P systems with promoters and cell division using only antiport rules of length 2. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Membrane computing Tissue P system Symport/antiport rule Promoter Universality SAT problem

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On-line reentry guidance algorithm with both path and no-fly zone constraints

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ACTA ASTRONAUTICA 2015年第Dec.期117卷 243-253页

作者： Zhang, Da Liu, Lei Wang, Yongji Huazhong Univ Sci & Technol Sch Automat Minist Educ Image Proc & Intelligent Control Key Lab Wuhan 430074 Peoples R China

This study proposes an on-line predictor-corrector reentry guidance algorithm that satisfies path and no-fly zone constraints for hypersonic vehicles with a high lift-to-drag ratio. The proposed guidance algorithm can generate a feasible trajectory at each guidance cycle during the entry flight. In the longitudinal profile, numerical predictor-corrector approaches are used to predict the flight capability from current flight states to expected terminal states and to generate an on-line reference drag acceleration profile. The path constraints on heat rate, aerodynamic load, and dynamic pressure are implemented as a part of the predictor-corrector algorithm. A tracking control law is then designed to track the reference drag acceleration profile. In the lateral profile, a novel guidance algorithm is presented. The velocity azimuth angle error threshold and artificial potential field method are used to reduce heading error and to avoid the no-fly zone. Simulated results for nominal and dispersed cases show that the proposed guidance algorithm not only can avoid the no-fly zone but can also steer a typical entry vehicle along a feasible 3D trajectory that satisfies both terminal and path constraints. (C) 2015 IAA. Published by Elsevier Ltd. All rights reserved.

关键词： On-line entry guidance Numerical predictor-corrector approach No-fly zone Artificial potential field

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An Automatic Analog Instrument Reading System Using Computer Vision and Inspection Robot

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2020年第9期69卷 6322-6335页

作者： Huang, Jian Wang, Junzhe Tan, Yihua Wu, Dongrui Cao, Yu Huazhong Univ Sci & Technol Sch Artificial Intelligence & Automat Key Lab Image Proc & Intelligent Control Wuhan 430074 Peoples R China

Since the manual inspection of analog instruments is inefficient, many computer vision-based automatic reading systems have been proposed recently. However, most of them use fixed cameras that are costly due to a large number of used cameras. Although some other systems adopting the pan-tilt-zoom camera and the movable inspection robot can avoid using many cameras, they have to overcome high computational cost in aligning the camera to the tested instrument. Meanwhile, most existing systems are instrument type-dependent and, hence, cannot handle multiple types of instruments simultaneously. In this article, first, based on an inspection robot, an automatic reading system equipped with a pan-tilt-zoom camera is designed for different types of round-shape analog instruments. Then, a fast camera alignment algorithm based on visual servo is proposed, in which YOLOv3 is applied and improved to locate the instrument and guide the camera to iteratively align with the instrument. Finally, a monocular-vision pointer reconstruction algorithm is proposed to accurately read the instrument. Experimental results demonstrated that our proposed system is fast and reliable in the camera-alignment process and is effective in reading different types of analog instruments during the robot-based inspection.

关键词： Instruments Cameras Robot vision systems Inspection Navigation Detectors Analog instrument automatic reading system fast camera alignment monocular-vision pointer reconstruction robot-based inspection

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controllability of the better chosen partial networks

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PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2016年 456卷 120-127页

作者： Liu, Xueming Pan, Linqiang Huazhong Univ Sci & Technol Sch Automat Key Lab Image Informat Proc & Intelligent Control Wuhan 430074 Hubei Peoples R China

How to control large complex networks is a great challenge. Recent studies have proved that the whole network can be sufficiently steered by injecting control signals into a minimum set of driver nodes, and the minimum numbers of driver nodes for many real networks are high, indicating that it is difficult to control them. For some large natural and technological networks, it is impossible and not feasible to control the full network. For example, in biological networks like large-scale gene regulatory networks it is impossible to control all the genes. This prompts us to explore the question how to choose partial networks that are easy for controlling and important in networked systems. In this work, we propose a method to achieve this goal. By computing the minimum driver nodes densities of the partial networks of Erdos-Renyi (ER) networks, scale-free (SF) networks and 23 real networks, we find that our method performs better than random method that chooses nodes randomly. Moreover, we find that the nodes chosen by our method tend to be the essential elements of the whole systems, via studying the nodes chosen by our method of a real human signaling network and a human protein interaction network and discovering that the chosen nodes from these networks tend to be cancer-associated genes. The implementation of our method shows some interesting connections between the structure and the controllability of networks, improving our understanding of the control principles of complex systems. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Complex network controllability Partial network Driver node

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Viewpoint Transform Matching model for person re-identification

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NEUROCOMPUTING 2021年 433卷 19-27页

作者： Zheng, Ruochen Gao, Changxin Sang, Nong Huazhong Univ Sci & Technol Sch Artificial Intelligence & Automat Key Lab Image Proc & Intelligent Control Wuhan 430074 Peoples R China

Person re-identification is a challenging problem that aims at matching persons across multiple non overlapping cameras. Previous works on person re-identification mainly focus on solving the problems caused by pose variations, backgrounds, and occlusion while ignoring the viewpoint variations. To address the viewpoint problem, we propose a Viewpoint Transform Matching (VTM) model, which reduces the inference of viewpoints by feature-level viewpoint transformation. Overall, we design a framework by using viewpoint specific branches to separately extract the representation of different viewpoints. Specifically, we first select the branch for an input image, according to its viewpoint information. In the branch, we transform the feature to other viewpoints by establishing a mutually transformable connection between the features of different viewpoints. To suppress the interference among viewpoints, we propose a viewpoint transform classifier module to independently train a classifier for each viewpoint. To improve the effectiveness of the transform, we propose a viewpoint transform loss to guarantee the consistency of the original features and the transformed features. Experiments conducted on Market-1501, DukeMTMC-reID and CUHK03 show the effectiveness of the proposed method. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Person re-identification Viewpoint Transform Matching Deep learning

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Latent Distribution-Based 3D Hand Pose Estimation From Monocular RGB images

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2021年第12期31卷 4883-4894页

作者： Li, Moran Wang, Jialong Sang, Nong Huazhong Univ Sci & Technol Sch Artificial Intelligence & Automat Key Lab Image Proc & Intelligent Control Wuhan 430074 Peoples R China

In this article, we propose a novel compressed latent distribution representation for 3D hand pose estimation from monocular RGB images to alleviate the channel correspondence problem. The channel correspondence problem occurs when the 2D and depth coordinates are estimated from independent feature maps, which means the 2D and depth channel sequences may not match during the cross-dataset inference. In contrast, we propose a compressed latent distribution representation that the 2D and depth feature maps for each joint are interconnected and inter-constrained more directly, effectively alleviating the channel correspondence problem and improving cross-dataset performance. Moreover, we design an efficient encoder-decoder network that can maintain the resolution of feature maps to enable better hand feature extraction from monocular RGB images. In this work, the overall pipeline contains two branches: one is the 2D hand pose estimation branch based on a latent heatmap representation (LHR);the other is the 3D hand pose estimation branch based on our proposed latent distribution representation (LDR). In this way, the 2D estimation branch serves as guidance for the 3D branch, which simplifies the optimization of the overall network and results in a more rapid convergence during training. The results on several benchmark datasets (including STB, RHD, and the most recently released InterHand2.6M) demonstrate that our proposed method achieves state-of-the-art (SOTA) performance.

关键词： Three-dimensional displays Pose estimation Two dimensional displays Heating systems Cameras Neural networks Feature extraction 3D hand pose estimation latent representation

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