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西南大学2014年全国博士生学术论坛(电子技术与信息科学领域)

作者： Qingdu Li Song Tang Hongzheng Zeng Tingting Zhou Key Laboratory of Industrial Internet of Things & Networked Control of Ministry of Education Chongq Research Center of Analysis and Control for Complex Systems Chongqing University of Posts and Telec

This paper studies a small Hopfield neural network with a memristive synaptic *** show that the previous stable network after one weight replaced by a memristor can exhibit rich complex dynamics, such as quasi-periodic orbits, chaos, and hyperchaos, which suggests that the memristor is crucial to the behaviors of neural networks and may play a significant *** also prove the existence of a saddle periodic orbit, and then present computer-assisted verification of hyperchaos through a homoclinic intersection of the stable and unstable manifolds, which gives a positive answer to an interesting question that whether a 4D memristive system with a line of equilibria can demonstrate hyperchaos.

关键词： Hyperchaos Homoclinic intersection Small neural networks Memristor

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Causal Inference in Social Media Using Convergent Cross Mapping

Causal Inference in Social Media Using Convergent Cross Mapp...

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IEEE Joint Intelligence and Security Informatics Conference (JISIC)

作者： Chuan Luo Xiaolong Zheng Daniel Zeng State Key Laboratory of Management and Control for Complex Systems Chinese Academy of Sciences Beijing China Department of Management Information Systems University of Arizona Tucson USA

Revealing underlying causal structure in social media is critical to understanding how users interact, on which a lot of security intelligence applications can be built. Existing causal inference methods for social media usually rely on limited explicit causal context, pre-assume certain user interaction model, or neglect the nonlinear nature of social interaction, which could lead to bias estimations of causality. Inspired from recent advance in causality detection in complex ecosystems, we propose to take advantage of a novel nonlinear state space reconstruction based approach, namely Convergent Cross Mapping, to perform causal inference in social media. Experimental results on real world social media datasets show the effectiveness of the proposed method in causal inference and user behavior prediction in social media.

关键词： Media Time series analysis Manifolds Nonlinear dynamical systems Twitter Security

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Event-triggered consensus for discrete-time linear multi-agent systems under general directed graphs

Event-triggered consensus for discrete-time linear multi-age...

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World Congress on Intelligent control and Automation (WCICA)

作者： Dapeng Yang Xiangdong Liu National Key Laboratory for Intelligent Control & Decision of Complex Systems Beijing China School of Automation Beijing Institute of Technology Beijing China

This paper considers the decentralized event-triggered consensus problem for discrete-time linear multi-agent systems. The communication topology among agents is assumed to be a general directed graph containing a spanning tree. We propose an event-based consensus control algorithm rendering the states of agents reach consensus. The triggering condition is decentralized only based on the agent's own information. Compared to the traditional consensus control law which needs communication at every iteration, the proposed event-triggered consensus algorithm in this paper can reduce the communication load greatly. Simulation is given to illustrate the theoretical results.

关键词： Eigenvalues and eigenfunctions Vectors Vehicle dynamics Measurement errors Closed loop systems Multi-agent systems Topology

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Distributed cooperative attitude tracking control for multiple rigid spacecraft using fast terminal sliding mode

Distributed cooperative attitude tracking control for multip...

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World Congress on Intelligent control and Automation (WCICA)

作者： Chao Gan Pingli Lu Xiangdong Liu Dapeng Yang National Key Laboratory for Intelligent Control & Decision of Complex Systems Beijing China School of Automation Beijing Institute of Technology Beijing China

In this paper, the distributed cooperative attitude tracking control law based on a new modified fast terminal sliding mode is presented for multiple spacecraft formation flying in the presence of model uncertainty and external disturbance. Firstly, to speed the convergence rate and avoid the singularity problem, a new modified fast terminal sliding mode manifold is proposed. Then, based on the proposed terminal sliding mode manifold, the distributed cooperative attitude tracking controller is designed for the spacecraft formation flying(SFF) in the presence of model uncertainty and external disturbance, Meanwhile, the finite time stability of SFF system can be also guaranteed. Finally, numerical simulation is given to verify the validity of the proposed control algorithm.

关键词： Space vehicles Attitude control Convergence Uncertainty Manifolds Equations Symmetric matrices

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Analyzing long-term correlated stochastic processes by means of recurrence networks: Potentials and pitfalls

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Physical Review E 2015年第2期91卷 022926-022926页

作者： Yong Zou Reik V. Donner Jürgen Kurths Department of Physics East China Normal University 200062 Shanghai China State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China Potsdam Institute for Climate Impact Research P. O. Box 60 12 03 14412 Potsdam Germany Department of Physics Humboldt University Berlin Newtonstraße 15 12489 Berlin Germany Institute for Complex Systems and Mathematical Biology University of Aberdeen Aberdeen AB243UE United Kingdom Department of Control Theory Nizhny Novgorod State University Gagarin Avenue 23 606950 Nizhny Novgorod Russia

Long-range correlated processes are ubiquitous, ranging from climate variables to financial time series. One paradigmatic example for such processes is fractional Brownian motion (fBm). In this work, we highlight the potentials and conceptual as well as practical limitations when applying the recently proposed recurrence network (RN) approach to fBm and related stochastic processes. In particular, we demonstrate that the results of a previous application of RN analysis to fBm [Liu et al. Phys. Rev. E 89, 032814 (2014)] are mainly due to an inappropriate treatment disregarding the intrinsic nonstationarity of such processes. Complementarily, we analyze some RN properties of the closely related stationary fractional Gaussian noise (fGn) processes and find that the resulting network properties are well-defined and behave as one would expect from basic conceptual considerations. Our results demonstrate that RN analysis can indeed provide meaningful results for stationary stochastic processes, given a proper selection of its intrinsic methodological parameters, whereas it is prone to fail to uniquely retrieve RN properties for nonstationary stochastic processes like fBm.

关键词： STOCHASTIC processes CLIMATIC changes TIME series analysis BROWNIAN motion RANDOM noise theory

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Nearly Optimal control Scheme for Discrete-Time Nonlinear systems With Finite Approximation Errors Using Generalized Value Iteration Algorithm

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IFAC Proceedings Volumes 2014年第3期47卷 4134-4139页

作者： Qinglai Wei Derong Liu The State Key Laboratory of Management and Control for Complex Systems Institute of Automation Chinese Academy of Sciences Beijing 100190 China (Tel: +86-10-82544761 Fax: +86-10-82544799

In this paper, a new generalized value iteration algorithm is developed to solve infinite horizon optimal control problems for discrete-time nonlinear systems. The idea is to use iterative adaptive dynamic programming (ADP) to obtain the iterative control law which makes the iterative performance index function reach the optimum. The generalized value iteration algorithm permits an arbitrary positive semi-definite function to initialize it, which overcomes the disadvantage of traditional value iteration algorithms. When the iterative control law and iterative performance index function in each iteration cannot be accurately obtained, a new design method of the convergence criterion for the generalized value iteration algorithm with finite approximation errors is established to make the iterative performance index functions converge to a finite neighborhood of the lowest bound of all performance index functions. Simulation results are given to illustrate the performance of the developed algorithm.

关键词： Adaptive dynamic programming approximate dynamic programming nonlinear system optimal control reinforcement learning

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Closed-loop controlled nanoprobing inside SEM

Closed-loop controlled nanoprobing inside SEM

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IEEE Conference on Nanotechnology

作者： Chao Zhou Zheng Gong Brandon K. Chen Min Tan Yu Sun State Key Laboratory of Management and Control for Complex Systems Chinese Academy of Sciences Beijing China Advanced Micro and Nanosystems Laboratory University of Toronto Toronto ON Canada

Probing nanostructures (e.g., nanoelectronics) requires accurate and precise nanopositioning. Furthermore, since measuring I-V data from DC to GHz typically takes more than a minute, little drift is tolerated during the data collection process. This paper reports a closed-loop controlled nanomanipulation system for operation inside a scanning electron microscope (SEM). The system consists of long range coarse positioners and high precision fine positioners. A new position sensing method was developed to achieve nanometer sensing resolution. Closed-loop controller is introduced to control fine. Experimental results demonstrate that the system is capable of automated probing of nanostructures with accuracy better than 3 nm and a drift rate

关键词： Scanning electron microscopy Nanobioscience Strain Nanostructures Sensor systems Manipulators

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Unbiased Minimum-Variance Filtering for systems with Randomly Multi-Step Sensor Delays

Unbiased Minimum-Variance Filtering for Systems with Randoml...

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Annual Conference of the IEEE Industrial Electronics Society

作者： Yilian Zhang Fuwen Yang Qing-Long Han Key Laboratory of Advanced Control and Optimization for Chemical Processes of Ministry of Education East China University of Science and Technology Centre for Intelligent and Networked Systems Central Queensland University

ISBN: (纸本)9781479940318

In this paper, a linear unbiased minimum-variance filtering problem is considered for a class of systems with randomly multi-step sensor delays. A new mathematical model is established for the multi-step sensor delays. Different from the augmented method for dealing with delayed systems, a linear unbiased minimum-variance filter design method is proposed without augmenting the state vector, which effectively reduces the filter dimensions. A recursive algorithm for calculating the filter gain matrix is developed. The simulation results illustrate the effectiveness of the proposed method.

关键词： Networked control systems Filtering Recursive estimation Kalman filters Delay systems Stochastic processes Sensor system Communication networks

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A probabilistic spectral graph matching algorithm for robust correspondence between lunar surface images

A probabilistic spectral graph matching algorithm for robust...

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World Congress on Intelligent control and Automation (WCICA)

作者： Xu Yang Chuan-Kai Liu Zhi-Yong Liu Hong Qiao Bao-Feng Wang Zi-Dong Wang State Key Laboratory of Management and Control for Complex Systems Chinese Academy of Sciences Beijing Aerospace Flight Control Center School of Information Science and Technology Donghua University

The correspondence between key points is an important problem in lunar surface image processing, and further lays the foundation for the navigation of a rover and the terrain reconstruction of the lunar surface. However, the problem is still challenging due to the existence of large scale and rotation transformations, reflected view of the same scenery, and different illumination conditions between acquired images as the lunar rover moves forward. Traditional appearance matching algorithms, like SIFT, often fail in handling the above situations. By utilizing the structural cues between points, in this paper we propose a probabilistic spectral graph matching method to tackle the point correspondence problem in lunar surface images acquired by Yutu lunar rover which has been recently transmitted to the moon by China's Chang'e-3 lunar probe. Compared with traditional methods, the proposed method has three advantages. First, the incorporation of the structural information makes the matching more robust with respect to geometric transformations and illumination changes. Second, the assignment between points is interpreted in a probabilistic manner, and thus the best assignments can be easily figured out by ranking the probabilities. Third, the optimization problem can be efficiently approximately solved by spectral decomposition. Simulations on real lunar surface images witness the effectiveness of the proposed method.

关键词： Moon Probabilistic logic Image edge detection Surface treatment Accuracy optimization Robustness

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Rotor design techniques for reducing the cogging torque in a novel dual-rotor axial field flux-switching permanent magnet machine

Rotor design techniques for reducing the cogging torque in a...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Li Hao Mingyao Lin Da Xu Wei Zhang Nian Li Key Laboratory of Measurement and Control of Complex Systems of Engineering Southeast University Nanjing China Engineering Research Center for Motion Control of MOE Southeast University Nanjing China

ISBN: (纸本)9781479951635

Dual-rotor axial field flux-switching permanent magnet (DRAFFSPM) machine is a novel permanent magnet (PM) machine which incorporates the merits of both the flux-switching PM machine and the axial field PM machine. The cogging torque of the DRAFFSPM machine is high due to the flux focusing which is caused by the double salient structure. In order to reduce the cogging torque, the influence of the rotor pole width and shape on the cogging torque is analyzed based on the 3D finite element (FE) method. The cogging torque reduction methods, such as the rotor skewing, rotor notching, and rotor pole displacement, etc., are investigated. The results show that increasing the rotor pole width and adopting fan-shaped rotor pole can decrease the cogging torque greatly. The cogging torque can be reduced by ~77% when the rotor pole width and rotor fan-shaped angle are optimized to 15.5 deg. and 3 deg., respectively. The cogging torque can't be decreased by the rotor skewing for DRAFFSPM machine. However, the cogging torque can be reduced by rotor notching and rotor pole displacement.

关键词： Rotors Forging Torque Shape Stator windings Permanent magnet motors

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