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Modular Fault Diagnosis in Fixed-Block Railway Signaling Systems

IFAC-PapersOnLine 2016年第3期49卷 459-464页

作者： Durmus, Mustafa S. Ustoglu, lker Tsarev, Roman Y. Schwarz, Michael Electrical and Electronics Engineering Department Pamukkale University Denizli Turkey Control and Automation Engineering Department Yildiz Technical University Istanbul Turkey Institute of Space and Information Technology Siberian Federal University Krasnoyarsk Russia Computer Architecture and System Programming Kassel University Kassel Germany

The diagnosis of possible faults in railway signaling systems is an important issue to provide safe travel and transportation in railways. Signaling system designers have to consider the possible faults which may occur in railway field components both on the requirements preparation phase and on the development phase of the signaling system software or namely, the interlocking system. Although the diagnosis of different unobservable faults is relatively hard, especially for large scale railway fields, this complexity can be overcome by using the Discrete Event System (DES) based modular diagnosis approach which is explained in this paper. The main advantage of using such modular approach for fault diagnosis in fixed-block signaling systems is the inspection of the diagnosability of the whole system with respect to its subsystems (railway field components). In this study, the diagnosability of the railway field equipment and the whole system is also explained with a case study. © 2016

关键词： Fault detection Discrete event simulation Failure analysis Railroad signal systems Railroads Signaling Development phase Field components Field equipment Fixed block signaling Interlocking systems Modular approach Railway signaling systems Signaling systems

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Fault-tolerant control of deterministic I/O automata with ambiguous diagnostic result

Fault-tolerant control of deterministic I/O automata with am...

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International Workshop on Discrete Event Systems, WODES

作者： Melanie Schuh Jan Lunze Institute of Automation and Computer Control Ruhr-Universität Bochum Germany

A method for the active fault-tolerant control of discrete event systems modeled by deterministic Input/Output automata is proposed that can be applied if the diagnostic result consists of a set of fault candidates rather than a single fault. Based on the ambiguous diagnostic result a common model of the faulty plant is constructed that describes the identical part of the behavior of the plant under all fault candidates. Then the reconfiguration of the controller is performed based on this common model. It is proved that the resulting reconfigured tracking controller steers the faulty plant into the desired final state, no matter which fault actually occurred.

关键词： Automata Trajectory Fault tolerance Fault tolerant systems Tracking loops Discrete-event systems Planning

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Simultaneous control reconfiguration of systems with non-isolable actuator failures

Simultaneous control reconfiguration of systems with non-iso...

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American control Conference

作者： Daniel Vey Kai Schenk Jan Lunze Institute of Automation and Computer Control Ruhr-Universitat Bochum 44801 Germany

ISBN: (纸本)9781467386838

This paper presents an integrated active fault-tolerant control (FTC) approach for linear systems subject to actuator failures. The proposed method combines a bank of observers for diagnosis with the virtual actuator approach to reconfiguration. Usually, the two steps of FTC are considered separately in literature and the reconfiguration unit assumes that an unambiguous diagnosis result is available. This paper investigates the combination of the diagnosis and the reconfiguration unit. An analysis of the diagnosis unit shows that the failed actuator cannot always be isolated perfectly. Therefore, a method that solves the reconfiguration problem in cases of non-isolable actuator failures is presented. The solution is given by a common virtual actuator that reconfigures the non-isolable actuator failures simultaneously, without simply switching off all of them. It is shown that the common virtual actuator always exists for actuator failures that cannot be isolated by the diagnosis unit. The proposed integrated FTC approach is illustrated by an application to octorotors.

关键词： Actuators Observers Fault tolerance Fault tolerant systems Fault diagnosis Trajectory Linear systems actuators Fault tolerant systems Linear system Fault tolerance Observers Fault diagnosis trajectory Reconfiguration Coviracil

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A unified leader-follower scheme for mobile robots with uncalibrated on-board camera

A unified leader-follower scheme for mobile robots with unca...

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IEEE International Conference on Robotics and automation (ICRA)

作者： Dejun Guo Hesheng Wang Weidong Chen Ming Liu Zeyang Xia Kam K. Leang DARC (Design Automation Robotics & Control) Lab University of Utah Robotics Center Salt Lake City Utah USA State Key Laboratory of Robotics and System (HIT) Key Laboratory of System Control and Information Processing Ministry of Education of China Department of Automation Shanghai Jiao Tong University Shanghai China Department of Electronics and Computer Engineering Hong Kong University of Science and Technology Hong Kong China Institute of Biomedical and Health Engineering Chinese Academy of Sciences Shenzhen China

This paper studies the problem of image-based leader-follower formation control for mobile robots, where the controller is designed independently of the leader's motion. An adaptive control scheme, which is suitable for both omnidirectional and perspective cameras, is proposed. The proposed approach avoids the need for accurate calibration of the extrinsic parameters of the omnidirectional camera as well as the intrinsic and extrinsic parameters of perspective camera. Additionally, the coefficients of the plane where the feature point moves relative to the camera frame can be uncertain. These uncertain constant parameters are estimated using an adaptive estimator. Uniform Semi-global Practical Asymptotic Stability (USPAS) of the system is shown using the Lyapunov approach. Experimental results are presented to demonstrate the effectiveness of the proposed control scheme.

关键词： Cameras Robot vision systems Kinematics Mobile robots Calibration automation

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Optimal Innovation-Based Deception Attack on Remote State Estimation

Optimal Innovation-Based Deception Attack on Remote State Es...

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American control Conference

作者： Shuang Wu Ziyang Guo Dawei Shi Karl Henrik Johansson Ling Shi Electronic and Computer Engineering Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong State Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology 100081 China ACCESS Linnaeus Centre School of Electrical Engineering KTH Royal Institute of Technology Stockholm Sweden

ISBN: (纸本)9781509045839

The security issue in cyber-physical systems has attracted growing interests in the last decades. This paper considers how false data injection attack can degrade the estimation quality of a remote state estimation system. In this system, smart sensors measure a dynamic process and send preprocessed data through a communication network to a remote estimator to estimate the process. It is assumed that there are malicious attackers in the communication network, who are able to obtain and falsify all the data sent by the sensors. It is common that the remote estimator is equipped with a residue-based detector to detect potential attacks. We propose a class of deception attack and analyze its feasibility. We show that the proposed attack enables the attacker to inject false data into the remote estimator without being detected. We derive a criterion to judge the optimality of performance of this type of attack in the sense of maximizing the estimation error covariance. Furthermore, we find that a simple linear attack strategy, which flips the sign of intercepted signal, satisfies the optimality criterion. We present numerical examples to illustrate our theoretical results.

关键词： Cyber-physical systems (CPS) deception attack remote state estimation

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Robust and Scalable Power System State Estimation via Composite Optimization

arXiv

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arXiv 2017年

作者： Wang, Gang Giannakis, Georgios B. Chen, Jie Digital Technology Center and the Electrical and Computer Engineering Department University of Minnesota MinneapolisMN55455 United States State Key Lab of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Tongji University Shanghai200072 China

—In today’s cyber-enabled smart grids, high penetration of uncertain renewables, purposeful manipulation of meter readings, and the need for wide-area situational awareness, call for fast, accurate, and robust power system state estimation. The least-absolute-value (LAV) estimator is known for its robustness relative to the weighted least-squares (WLS) one. However, due to nonconvexity and nonsmoothness, existing LAV solvers based on linear programming are typically slow, hence inadequate for real-time system monitoring. This paper develops two novel algorithms for efficient LAV estimation, which draw from recent advances in composite optimization. The first is a deterministic linear proximal scheme that handles a sequence of (5 ∼ 10 in general) convex quadratic problems, each efficiently solvable either via off-the-shelf toolboxes or through the alternating direction method of multipliers. Leveraging the sparse connectivity inherent to power networks, the second scheme is stochastic, and updates only a few entries of the complex voltage state vector per iteration. In particular, when voltage magnitude and (re)active power flow measurements are used only, this number reduces to one or two, regardless of the number of buses in the network. This computational complexity evidently scales well to large-size power systems. Furthermore, by carefully mini-batching the voltage and power flow measurements, accelerated implementation of the stochastic iterations becomes possible. The developed algorithms are numerically evaluated using a variety of benchmark power networks. Simulated tests corroborate that improved robustness can be attained at comparable or markedly reduced computation times for medium- or large-size networks relative to existing alternatives. Copyright © 2017, The Authors. All rights reserved.

关键词： Electric power transmission networks

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Learning a Variational Network for Reconstruction of Accelerated MRI Data

arXiv

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arXiv 2017年

作者： Hammernik, Kerstin Klatzer, Teresa Kobler, Erich Recht, Michael P Sodickson, Daniel K Pock, Thomas Knol, Florian Institute of Computer Graphics and Vision Graz University of Technology Graz Austria Department of Radiology United States Nyu School of Medicine New YorkNY United States United States Nyu School of Medicine New YorkNY United States Center for Vision Ait Austrian Institute of Technology GmbH Automation & Control Vienna Austria Institute of Computer Graphics and Vision Graz University of Technology Ineldgasse 16/II Graz8010 Austria

Purpose: To allow fast and high-quality reconstruction of clinical accelerated multi-coil MR data by learning a variational network that combines the mathematical structure of variational models with deep *** and Methods: Generalized compressed sensing reconstruction formulated as a variational model is embedded in an unrolled gradient descent scheme. All parameters of this formulation, including the prior model defined by filter kernels and activation functions as well as the data term weights, are learned during an offline training procedure. The learned model can then be applied online to previously unseen ***: The variational network approach is evaluated on a clinical knee imaging protocol. The variational network reconstructions outperform standard reconstruction algorithms in terms of image quality and residual artifacts for all tested acceleration factors and sampling ***: Variational network reconstructions preserve the natural appearance of MR images as well as pathologies that were not included in the training data set. Due to its high computational performance, i.e., reconstruction time of 193 ms on a single graphics card, and the omission of parameter tuning once the network is trained, this new approach to image reconstruction can easily be integrated into clinical workflow. Copyright © 2017, The Authors. All rights reserved.

关键词： Image reconstruction

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7.3: Compare Variation of User's EEG Owing to Parallax Cue

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SID Symposium Digest of Technical Papers 2018年第S1期49卷

作者： Haichen Hu Danli Wang Kang Yue Xinpan Yang Steve C. Chiu Beijing Key Lab of Human-Computer Interaction Institute of Software Chinese Academy of Sciences Beijing China University of Chinese Academy of Sciences Beijing China The State Key Laboratory of Management and Control of Complex Systems Institute of Automation Chinese Academy of Sciences Beijing China College of Science and Engineering Idaho State University Pocatello America

3D display has become increasingly popular in many fields. It can provide incredible immersion compared with 2D display. There are many researches referring to the change of user about no matter subjective experience or objective physiology signal while watching 3D content. Similarly, in this paper, we study the variation of user’s EEG when the user watched 3D content. However, we only focus on parallax cue and avoid other cues of 3D content by using Random Dot Stereogram(RDS) as visual stimulus. We designed an experiment which asked the subject to watch RDS with nine kinds of parallaxes(0,±0.5,±1.1,±1.3,±1.7). The users watched one RDS for 1 minute and then closed eyes and rest for 1 minute every time. During watching, EEG signal with 30-channel was recorded. The result suggests that significant variation of the user’s EEG data occurred in the Alpha (8–13Hz) and Beta(14–30Hz) frequency band by different parallax’s comparison. And we found not only parallax but also electrode position can impact the user’s EEG data significantly. Accurately, the EEG data has a significant change in six electrodes position in both frequency bands including CZ, PZ, OZ, O2 in international 10–20 system. It means those electrode positions we detect can be regarded as typical positions where we record EEG signal. It will simplify the process of EEG signal acquisition when we need to study the relationship between parallax cue of 3D display and the user further.

关键词： EEG Parallax RDS 3D

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Joint hierarchical category structure learning and large-scale image classification

arXiv

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arXiv 2017年

作者： Qu, Yanyun Lin, Li Shen, Fumin Lu, Chang Wu, Yang Xie, Yuan Tao, Dacheng Department of Computer Science Xiamen University Xiamen361005 China School of Computer Science and Engineering University of Electric Science and technology of China Chengdu611731 China Institute for Research Initiatives Nara Institute of Science and Technology Japan Research Center of Precision Sensing and Control Institute of Automation Chinese Academy of Sciences Beijing100190 China Centre for Artificial Intelligence Faculty of Engineering and Information Technology University of Technology Sydney 81 Broadway Street UltimoNSW2007 Australia

—We investigate the scalable image classification problem with a large number of categories. Hierarchical visual data structures are helpful for improving the efficiency and performance of large-scale multi-class classification. We propose a novel image classification method based on learning hierarchical inter-class structures. Specifically, we first design a fast algorithm to compute the similarity metric between categories, based on which a visual tree is constructed by hierarchical spectral clustering. Using the learned visual tree, a test sample label is efficiently predicted by searching for the best path over the entire tree. The proposed method is extensively evaluated on the ILSVRC2010 and Caltech 256 benchmark datasets. Experimental results show that our method obtains significantly better category hierarchies than other state-of-the-art visual tree-based methods and, therefore, much more accurate classification. Copyright © 2017, The Authors. All rights reserved.

关键词： Image classification

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Towards a reduced virtual actuator: A graph-theoretic approach

Towards a reduced virtual actuator: A graph-theoretic approa...

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European control Conference

作者： Daniel Vey Jan Lunze Institute of Automation and Computer Control Ruhr-Universit?t Bochum 44801 Bochum Germany

ISBN: (纸本)9781509025923

This paper presents a new method for minimum invasive control reconfiguration after actuator failures. As an actuator failure usually affects only a part of the plant, only a few available components are necessary to compensate this failure. However, the design of a virtual actuator is based on the model of the overall plant and makes use of all available components, and modifies the overall control loop. In this paper a reduced virtual actuator that guarantees stabilisation of the overall control loop is introduced. First, the effect of a failure and the necessary redundancies are identified by a structural analysis. Second, an algorithm is presented that finds a subsystem that is admissible for the design of a reduced virtual actuator. The reduced virtual actuator constrains the modifications in the control loop to the part of the plant that is affected by the failure and makes only use of a subset of the actuators. The proposed reconfiguration method is illustrated by its application to a thermo-fluid process.

关键词： Towards reduced virtual actuator graph-theoretic approach

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