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COMPUTER SCIENCE (1157 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 13)
Abakós     Open Access   (Followers: 3)
Academy of Information and Management Sciences Journal     Full-text available via subscription   (Followers: 69)
ACM Computing Surveys     Hybrid Journal   (Followers: 22)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 9)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 11)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 13)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 3)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 1)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 20)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 8)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 8)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 11)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 21)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 16)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Computer Science : an International Journal     Open Access   (Followers: 13)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 53)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Human-Computer Interaction     Open Access   (Followers: 20)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 1)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 6)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 7)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 4)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 7)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 9)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annual Reviews in Control     Hybrid Journal   (Followers: 6)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applied and Computational Harmonic Analysis     Full-text available via subscription   (Followers: 2)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 14)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Computer Systems     Open Access   (Followers: 1)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 32)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 125)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 6)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Computer Science and Information Technology     Open Access  
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access  
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 3)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 9)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Bioinformatics     Hybrid Journal   (Followers: 308)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 46)
British Journal of Educational Technology     Hybrid Journal   (Followers: 123)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 2)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
Cell Communication and Signaling     Open Access   (Followers: 1)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access  
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 12)
Circuits and Systems     Open Access   (Followers: 16)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Communication Methods and Measures     Hybrid Journal   (Followers: 11)
Communication Theory     Hybrid Journal   (Followers: 20)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 53)
Communications of the Association for Information Systems     Open Access   (Followers: 18)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access  
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 14)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Research     Open Access   (Followers: 1)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 13)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 31)
Computer     Full-text available via subscription   (Followers: 84)
Computer Aided Surgery     Hybrid Journal   (Followers: 3)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 7)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 22)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 10)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 1)
Computer Music Journal     Hybrid Journal   (Followers: 16)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computer Science and Information Technology     Open Access   (Followers: 11)
Computer Science Education     Hybrid Journal   (Followers: 12)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Master Research     Open Access   (Followers: 10)
Computer Science Review     Hybrid Journal   (Followers: 10)

        1 2 3 4 5 6 | Last

Journal Cover Automatica
  [SJR: 4.315]   [H-I: 188]   [9 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0005-1098
   Published by Elsevier Homepage  [3044 journals]
  • New unknown input observer and output feedback stabilization for uncertain
           heat equation
    • Authors: Hongyinping Feng; Bao-Zhu Guo
      Pages: 1 - 10
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Hongyinping Feng, Bao-Zhu Guo
      In this paper, we propose a new method, by designing an unknown input type state observer, to stabilize an unstable 1-d heat equation with boundary uncertainty and external disturbance. The state observer is designed in terms of a disturbance estimator. A stabilizing state feedback control is designed for the observer by the backstepping transformation, which is an observer based output feedback stabilizing control for the original system. The well-posedness and stability of the closed-loop system are concluded. The numerical simulations show that the proposed scheme is quite effectively. This is a first result on active disturbance rejection control for a PDE with both boundary uncertainty and external disturbance.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.004
      Issue No: Vol. 86 (2017)
  • A nonlinear Luenberger-like observer for nonlinear singular systems
    • Authors: Gang Zheng; Driss Boutat; Haoping Wang
      Pages: 11 - 17
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Gang Zheng, Driss Boutat, Haoping Wang
      This paper investigates observer design problem for a large class of nonlinear singular systems with multiple outputs. We first regularize the singular system by injecting the derivative of outputs into the system. Then differential geometric method is applied to transform the regularized system into a simple normal form, for which a Luenberger-like observer is proposed.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.018
      Issue No: Vol. 86 (2017)
  • Semi-analytical minimum time solutions with velocity constraints for
           trajectory following of vehicles
    • Authors: Marco Frego; Enrico Bertolazzi; Francesco Biral; Daniele Fontanelli; Luigi Palopoli
      Pages: 18 - 28
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Marco Frego, Enrico Bertolazzi, Francesco Biral, Daniele Fontanelli, Luigi Palopoli
      We consider the problem of finding an optimal manoeuvre that moves a car-like vehicle between two configurations in minimum time. We propose a two phase algorithm in which a path that joins the two points is first found by solving a geometric optimisation problem, and then the optimal manoeuvre is identified considering the system dynamics and its constraints. We make the assumption that the path is composed of a sequence of clothoids. This choice is justified by theoretical arguments, practical examples and by the existence of very efficient geometric algorithms for the computation of a path of this kind. The focus of the paper is on the computation of the optimal manoeuvre, for which we show a semi-analytical solution that can be produced in a few milliseconds on an embedded platform for a path made of one hundred segments. Our method is considerably faster than approaches based on pure numerical solutions, it is capable to detect when the optimal solution exists and, in this case, compute the optimal control. Finally, the method explicitly considers nonlinear dynamics, aerodynamic drag effect and bounds on the longitudinal and on the lateral acceleration.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.020
      Issue No: Vol. 86 (2017)
  • Stochastic stability of Markov jump hyperbolic systems with application to
           traffic flow control
    • Authors: Liguo Zhang; Christophe Prieur
      Pages: 29 - 37
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Liguo Zhang, Christophe Prieur
      In this paper, we investigate the stochastic stability of linear hyperbolic conservation laws governed by a finite-state Markov chain. Both system matrices and boundary conditions are subject to the Markov switching. The existence and uniqueness of weak solutions are developed for the stochastic hyperbolic initial–boundary value problem. By means of Lyapunov techniques some sufficient conditions are obtained by seeking the balance between the boundary condition and the transition probability of the Markov process. Particularly, boundary feedback control of a stochastic traffic flow model is developed for the freeway transportation system by integrating the on-ramp metering with the speed limit control.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.007
      Issue No: Vol. 86 (2017)
  • H−∕H∞ fault detection observer in finite frequency domain for linear
           parameter-varying descriptor systems
    • Authors: Zhenhua Wang; Peng Shi; Cheng-Chew Lim
      Pages: 38 - 45
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Zhenhua Wang, Peng Shi, Cheng-Chew Lim
      This paper considers H − ∕ H ∞ fault detection observer design in the finite frequency domain for a class of linear parameter-varying (LPV) descriptor systems. We propose a novel fault detection observer with a non-singular structure. To make the residual sensitive to faults and robust against disturbances, we develop a finite frequency H − ∕ H ∞ design method based on a generalized Kalman–Yakubovich–Popov lemma for LPV descriptor systems. Design conditions for the proposed fault detection observer are derived and converted as linear matrix inequalities. Simulation studies are conducted to demonstrate the performance of the proposed method.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.021
      Issue No: Vol. 86 (2017)
  • Second order sliding mode control for nonlinear affine systems with
           quantized uncertainty
    • Authors: Gian Paolo Incremona; Michele Cucuzzella; Antonella Ferrara
      Pages: 46 - 52
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Gian Paolo Incremona, Michele Cucuzzella, Antonella Ferrara
      This paper deals with the design of a Second-Order Sliding Mode (SOSM) control algorithm able to enhance the closed-loop performance depending on the current working conditions. The novelty of the proposed approach is the design of a nonsmooth switching line, based on the quantization of the uncertainties affecting the system. The quantized uncertainty levels allow one to define nested box sets in the auxiliary state space, i.e., the space of the sliding variable and its first time derivative, and select suitable control amplitudes for each set, in order to guarantee the convergence of the sliding variable to the sliding manifold in a finite time. The proposed algorithm is theoretically analyzed, proving the existence of an upperbound of the reaching time to the origin through the considered quantization levels.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.019
      Issue No: Vol. 86 (2017)
  • A Lyapunov-based distributed consensus filter for a class of nonlinear
           stochastic systems
    • Authors: Ahmadreza Jenabzadeh; Behrouz Safarinejadian
      Pages: 53 - 62
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Ahmadreza Jenabzadeh, Behrouz Safarinejadian
      This paper considers the distributed state estimation problem for nonlinear stochastic systems over sensor networks. It is assumed that the nonlinear functions are bounded in the pseudo Lipschitz condition. Based on the stochastic Lyapunov stability theory, a distributed consensus filter (DCF) is proposed for both continuous and discrete nonlinear stochastic systems for each node in a sensor network. It will be shown that the estimation errors of the proposed filters are exponentially ultimately bounded in the sense of mean square in terms of linear matrix inequality (LMI). Furthermore, a criterion is presented to optimize the filter gains based on minimizing the upper bound of mean-square error. Numerical examples are used to verify the theoretical results.

      PubDate: 2017-09-08T00:44:54Z
      DOI: 10.1016/j.automatica.2017.08.005
      Issue No: Vol. 86 (2017)
  • Generalized Kalman smoothing: Modeling and algorithms
    • Authors: Aleksandr Aravkin; James V. Burke; Lennart Ljung; Aurelie Lozano; Gianluigi Pillonetto
      Pages: 63 - 86
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Aleksandr Aravkin, James V. Burke, Lennart Ljung, Aurelie Lozano, Gianluigi Pillonetto
      State-space smoothing has found many applications in science and engineering. Under linear and Gaussian assumptions, smoothed estimates can be obtained using efficient recursions, for example Rauch–Tung–Striebel and Mayne–Fraser algorithms. Such schemes are equivalent to linear algebraic techniques that minimize a convex quadratic objective function with structure induced by the dynamic model. These classical formulations fall short in many important circumstances. For instance, smoothers obtained using quadratic penalties can fail when outliers are present in the data, and cannot track impulsive inputs and abrupt state changes. Motivated by these shortcomings, generalized Kalman smoothing formulations have been proposed in the last few years, replacing quadratic models with more suitable, often nonsmooth, convex functions. In contrast to classical models, these general estimators require use of iterated algorithms, and these have received increased attention from control, signal processing, machine learning, and optimization communities. In this survey we show that the optimization viewpoint provides the control and signal processing community great freedom in the development of novel modeling and inference frameworks for dynamical systems. We discuss general statistical models for dynamic systems, making full use of nonsmooth convex penalties and constraints, and providing links to important models in signal processing and machine learning. We also survey optimization techniques for these formulations, paying close attention to dynamic problem structure. Modeling concepts and algorithms are illustrated with numerical examples.

      PubDate: 2017-09-14T01:59:37Z
      DOI: 10.1016/j.automatica.2017.08.011
      Issue No: Vol. 86 (2017)
  • A theory of passive linear systems with no assumptions
    • Authors: Timothy H. Hughes
      Pages: 87 - 97
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Timothy H. Hughes
      We present two linked theorems on passivity: the passive behavior theorem, parts 1 and 2. Part 1 provides necessary and sufficient conditions for a general linear system, described by a set of high order differential equations, to be passive. Part 2 extends the positive-real lemma to include uncontrollable and unobservable state-space systems.

      PubDate: 2017-09-14T01:59:37Z
      DOI: 10.1016/j.automatica.2017.08.017
      Issue No: Vol. 86 (2017)
  • Control of a class of underactuated mechanical systems obviating matching
    • Authors: Rachit Mehra; Sumeet G. Satpute; Faruk Kazi; N.M. Singh
      Pages: 98 - 103
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Rachit Mehra, Sumeet G. Satpute, Faruk Kazi, N.M. Singh
      The presently established techniques for control of underactuated mechanical systems are dependent on solving partial differential equations (PDEs) arising out of matching conditions. In this brief a novel controller design methodology for (asymptotic) stabilization of nonlinear systems is proposed that obviates the need of solving PDEs to obtain the control laws. The geometry based energy shaping methodology forms the fully constructive procedure for control of underactuated mechanical systems. The control methodology is based on manipulating symmetric structure of the system such that the power flow is established between the controller and unactuated part of the system. The modifications leads to identification of the two new passive outputs which are further utilized for kinetic and potential shaping and the desired controller is obtained using passivity based techniques. The theory is illustrated with two benchmark examples.

      PubDate: 2017-09-14T01:59:37Z
      DOI: 10.1016/j.automatica.2017.07.033
      Issue No: Vol. 86 (2017)
  • An optimal control problem for mean-field forward–backward stochastic
           differential equation with noisy observation
    • Authors: Guangchen Wang; Hua Xiao; Guojing Xing
      Pages: 104 - 109
      Abstract: Publication date: December 2017
      Source:Automatica, Volume 86
      Author(s): Guangchen Wang, Hua Xiao, Guojing Xing
      This article is concerned with an optimal control problem derived by mean-field forward–backward stochastic differential equation with noisy observation, where the drift coefficients of the state equation and the observation equation are linear with respect to the state and its expectation. The control problem is different from the existing literature concerning optimal control for mean-field stochastic systems, and has more applications in mathematical finance, e.g., asset–liability management problem with recursive utility, systematic risk model. Using a backward separation method with a decomposition technique, two optimality conditions along with two coupled forward–backward optimal filters are derived. Linear–quadratic optimal control problems for mean-field forward–backward stochastic differential equations are studied.

      PubDate: 2017-09-14T01:59:37Z
      DOI: 10.1016/j.automatica.2017.07.018
      Issue No: Vol. 86 (2017)
  • Stability analysis and L1-gain characterization for switched positive
           systems under dwell-time constraint
    • Authors: Weiming Xiang; James Lam; Jun Shen
      Pages: 1 - 8
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Weiming Xiang, James Lam, Jun Shen
      This paper deals with the problems of stability analysis and L 1 -gain characterization for continuous-time switched systems consisting of positive subsystems. With the aid of a discretized copositive Lyapunov function, a sufficient condition ensuring the asymptotic stability of continuous-time switched positive systems under dwell-time constraint is obtained, which can be checked via linear programming. Furthermore, the conservatism of the proposed approach is studied and the result with least conservatism in the framework of discretized copositive Lyapunov function is obtained. The result is then extended to L 1 -gain characterization for switched positive systems. With a prescribed dwell time, an unweighted L 1 -gain can be computed via solving a linear programming problem. A numerical example and a practical traffic example are given to illustrate our results.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.016
      Issue No: Vol. 85 (2017)
  • State estimation for discrete-time Markov jump linear systems with
           time-correlated and mode-dependent measurement noise
    • Authors: Wei Liu; Peng Shi; Jeng-Shyang Pan
      Pages: 9 - 21
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Wei Liu, Peng Shi, Jeng-Shyang Pan
      The state estimation problem for discrete-time Markov jump linear systems corrupted by time-correlated and mode-dependent measurement noise is considered where the time-correlated and mode-dependent measurement noise is described via a discrete-time stochastic system with Markov parameter and Kronecker delta function. By defining the measurement noise in this manner, both time-correlation and periodic step change caused by the change of system environment or structure can be embodied in the measurement noise. A novel “distributed measurement differencing method” is applied to the problem of state estimation under consideration so that two algorithms are obtained using some results presented in this paper. The first algorithm is optimal in the sense of minimum mean-square error, which can exactly compute the minimum mean-square error estimate of system state. The second algorithm is suboptimal and the suboptimality of the algorithm is caused by using some Gaussian hypotheses. The two proposed algorithms are recursive and the proposed suboptimal algorithm has a time-independent complexity. The performance of the proposed suboptimal algorithm is illustrated using computer simulations.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.025
      Issue No: Vol. 85 (2017)
  • On the emergence of oscillations in distributed resource allocation
    • Authors: Thomas Holding; Ioannis Lestas
      Pages: 22 - 33
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Thomas Holding, Ioannis Lestas
      We consider the problem of resource allocation in a decentralised market where users and suppliers trade for a single commodity. Due to the lack of strict concavity, convergence to the optimal solution by means of classical gradient type dynamics for the prices and demands, is not guaranteed. In the paper we explicitly characterise in this case the asymptotic behaviour of trajectories and provide an exact characterisation of the limiting oscillatory solutions. Methods of modifying the dynamics are also given, such that convergence to an optimal solution is guaranteed, without requiring additional information exchange among the users.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.022
      Issue No: Vol. 85 (2017)
  • Output regulation for general linear heterodirectional hyperbolic systems
           with spatially-varying coefficients
    • Authors: Joachim Deutscher
      Pages: 34 - 42
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Joachim Deutscher
      This article presents a backstepping solution to the output regulation problem for general linear heterodirectional hyperbolic systems with spatially-varying coefficients. The disturbances can act at both boundaries, distributed in-domain or at the output to be controlled. The latter is defined at a boundary, distributed or pointwise in-domain and has not to be available for measurement. By utilizing backstepping coordinates it is shown that all design equations are explicitly solvable. This allows a simple determination of a state feedback regulator, that is implemented by a reference and a disturbance observer. Furthermore, an easy evaluation of the existence conditions for the resulting output feedback regulator is possible in terms of the plant transfer behaviour. In order to facilitate the parameterization of the regulator, the resulting closed-loop dynamics is directly related to the design parameters. The proposed backstepping-based design of the output feedback regulator is demonstrated for an unstable heterodirectional 4  ×  4 hyperbolic system.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.027
      Issue No: Vol. 85 (2017)
  • Output regulation for a class of linear boundary controlled first-order
           hyperbolic PIDE systems
    • Authors: Xiaodong Xu; Stevan Dubljevic
      Pages: 43 - 52
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Xiaodong Xu, Stevan Dubljevic
      This manuscript addresses the output regulation problem for a class of scalar boundary controlled first-order hyperbolic partial integro-differential equation (PIDE) systems with Fredholm integrals. In particular, with the advantage of the backstepping approach, simple structure systems can be obtained such that regulator equations for the state feedback regulator design are analyzed and solved in backstepping coordinates. Moreover, the finite time output regulation is achieved. In the observer-based output feedback regulator design, it is not necessary that the outputs to be controlled belong to the available output measurements and these outputs can be distributed, point-wise and/or boundary in nature, while the boundary placed measurements are used for regulator design. For the observer gains design, a transformation of the ODE–PDE system into an ODE–PDE cascade is considered. It is also shown that the separation principle holds for the output feedback regulator design and the exponential output regulation is realized for the resulting stable closed-loop system. Finally, the output regulation results are illustrated with two numerical simulations: a Korteweg–de Vries-like equation and a PDE–ODE interconnected system.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.036
      Issue No: Vol. 85 (2017)
  • Guaranteed cost fuzzy state observer design for semilinear parabolic PDE
           systems under pointwise measurements
    • Authors: Huai-Ning Wu; Huan-Yu Zhu
      Pages: 53 - 60
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Huai-Ning Wu, Huan-Yu Zhu
      This paper studies the guaranteed cost fuzzy state observer (GCFSO) design via pointwise measurement sensors for a class of distributed parameter systems described by semilinear parabolic partial differential equations (PDEs). Initially, a Takagi–Sugeno (T–S) fuzzy model is employed to accurately represent the original PDE system in a local region. Then, based on the T–S fuzzy model, a fuzzy state observer is constructed for the state estimation. By augmenting the state estimation error system with the fuzzy PDE system and utilizing Lyapunov technique and Wirtinger’s inequality, a fuzzy state observer design with a guaranteed cost is developed in terms of linear matrix inequalities (LMIs). The resulting fuzzy observer can exponentially stabilize the augmented system while providing an upper bound on the cost function of state estimation error. Moreover, a suboptimal GCFSO design problem is also addressed to make the upper bound as small as possible. Finally, the numerical simulation results on two examples demonstrate the effectiveness of the proposed method.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.026
      Issue No: Vol. 85 (2017)
  • Stabilization of infinite dimensional port-Hamiltonian systems by
           nonlinear dynamic boundary control
    • Authors: Hector Ramirez; Hans Zwart; Yann Le Gorrec
      Pages: 61 - 69
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Hector Ramirez, Hans Zwart, Yann Le Gorrec
      The conditions for existence of solutions and stability, asymptotic and exponential, of a large class of boundary controlled systems on a 1D spatial domain subject to nonlinear dynamic boundary actuation are given. The consideration of such class of control systems is motivated by the use of actuators and sensors with nonlinear behavior in many engineering applications. These nonlinearities are usually associated to large deformations or the use of smart materials such as piezo actuators and memory shape alloys. Including them in the controller model results in passive dynamic controllers with nonlinear potential energy function and/or nonlinear damping forces. First it is shown that under very natural assumptions the solutions of the partial differential equation with the nonlinear dynamic boundary conditions exist globally. Secondly, when energy dissipation is present in the controller, then it globally asymptotically stabilizes the partial differential equation. Finally, it is shown that assuming some additional conditions on the interconnection and on the passivity properties of the controller (consistent with physical applications) global exponential stability of the closed-loop system is achieved.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.045
      Issue No: Vol. 85 (2017)
  • A high-order Discontinuous Galerkin Method with mesh refinement for
           optimal control
    • Authors: João C.C. Henriques; João M. Lemos; Luís Eça; Luís M.C. Gato; António F.O. Falcão
      Pages: 70 - 82
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): João C.C. Henriques, João M. Lemos, Luís Eça, Luís M.C. Gato, António F.O. Falcão
      A high-order Discontinuous Galerkin (DG) finite element time-stepping method is applied for the numerical solution of optimal control problems within the framework of Pontryagin’s Maximum Principle. The method constitutes an efficient and versatile alternative to the well-known Pseudospectral (PS) methods. The two main advantages of DG in comparison with the PS methods are: the local nature of the piecewise polynomial solution and the straightforward implementation of element-wise mesh and polynomial refinement if required. Two types of non-linear optimal control problems were analysed: continuous and bang–bang time-solutions. In the case of bang–bang optimal control problems, anh-refinement strategy was developed to achieve agreement between the observed and the formal order of accuracy. The paper also deals with sub-optimal control problems where: (i) time-step is fixed and non-infinitesimal; (ii) the control has two modes (on/off); (iii) the control command is only applied at the beginning of each time-step; and iv) the number of switching instants is large and not known a priori.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.029
      Issue No: Vol. 85 (2017)
  • Decentralized adaptive fault-tolerant control for large-scale systems with
           external disturbances and actuator faults
    • Authors: Chun-Hua Xie; Guang-Hong Yang
      Pages: 83 - 90
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Chun-Hua Xie, Guang-Hong Yang
      This paper investigates the decentralized adaptive fault-tolerant control problem for a class of uncertain large-scale interconnected systems with disturbances and actuator faults including stuck, outage and loss of effectiveness. It is assumed that the upper bounds of the disturbances and stuck faults are unknown. The considered disturbances and unknown interconnections contain matched and mismatched parts. A decentralized adaptive control scheme with backstepping method is developed. Then, according to the information from the adaptive mechanism, the effects of both the actuator faults and the matched parts of disturbances and interconnections can be eliminated completely. Furthermore, cyclic-small-gain technique is introduced to address the mismatched interconnections such that the resulting closed-loop system is asymptotically stable with disturbance attenuation level γ . Compared with the existing results, disturbance rejection property can be guaranteed for each subsystem. Finally, a simulation example of a large-scale power system is provided to show the effectiveness of the proposed approach.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.037
      Issue No: Vol. 85 (2017)
  • Bayesian state estimation on finite horizons: The case of linear
           state–space model
    • Authors: Shunyi Zhao; Biao Huang; Yuriy S. Shmaliy
      Pages: 91 - 99
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Shunyi Zhao, Biao Huang, Yuriy S. Shmaliy
      The finite impulse response (FIR) filter and infinite impulse response filter including the Kalman filter (KF) are generally considered as two different types of state estimation methods. In this paper, the sequential Bayesian philosophy is extended to a filter design using a fixed amount of most recent measurements, with the aim of exploiting the FIR structure and unifying some basic FIR filters with the KF. Specifically, the conditional mean and covariance of the posterior probability density functions are first derived to show the FIR counterpart of the KF. To remove the dependence on initial states, the corresponding likelihood is further maximized and realized iteratively. It shows that the maximum likelihood modification unifies the existing unbiased FIR filters by tuning a weighting matrix. Moreover, it converges to the Kalman estimate with the increase of horizon length, and can thus be considered as a link between the FIR filtering and the KF. Several important properties including stability and robustness against errors of noise statistics are illustrated. Finally, a moving target tracking example and an experiment with a three degrees-of-freedom helicopter system are introduced to demonstrate effectiveness.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.043
      Issue No: Vol. 85 (2017)
  • Optimal capacity allocation for sampled networked systems
    • Authors: Xudong Chen; Mohamed-Ali Belabbas; Tamer Başar
      Pages: 100 - 112
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Xudong Chen, Mohamed-Ali Belabbas, Tamer Başar
      We consider the problem of estimating the states of weakly coupled linear systems from sampled measurements. We assume that the total capacity available to the sensors to transmit their samples to a network manager in charge of the estimation is bounded above, and that each sample requires the same amount of communication. Our goal is then to find an optimal allocation of the capacity to the sensors so that the time-averaged estimation error is minimized. We show that when the total available channel capacity is large, this resource allocation problem can be recast as a strictly convex optimization problem, and hence there exists a unique optimal allocation of the capacity. We further investigate how this optimal allocation varies as the available capacity increases. In particular, we show that if the coupling among the subsystems is weak, then the sampling rate allocated to each sensor is nondecreasing in the total sampling rate, and is strictly increasing if and only if the total sampling rate exceeds a certain threshold.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.039
      Issue No: Vol. 85 (2017)
  • On computing the distance to stability for matrices using linear
           dissipative Hamiltonian systems
    • Authors: Nicolas Gillis; Punit Sharma
      Pages: 113 - 121
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Nicolas Gillis, Punit Sharma
      In this paper, we consider the problem of computing the nearest stable matrix to an unstable one. We propose new algorithms to solve this problem based on a reformulation using linear dissipative Hamiltonian systems: we show that a matrix A is stable if and only if it can be written as A = ( J − R ) Q , where J = − J T , R ⪰ 0 and Q ≻ 0 (that is, R is positive semidefinite and Q is positive definite). This reformulation results in an equivalent optimization problem with a simple convex feasible set. We propose three strategies to solve the problem in variables ( J , R , Q ) : (i) a block coordinate descent method, (ii) a projected gradient descent method, and (iii) a fast gradient method inspired from smooth convex optimization. These methods require O ( n 3 ) operations per iteration, where n is the size of A . We show the effectiveness of the fast gradient method compared to the other approaches and to several state-of-the-art algorithms.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.047
      Issue No: Vol. 85 (2017)
  • On guaranteeing point capture in linear n-on-1 endgame interception
           engagements with bounded controls
    • Authors: Shmuel Yonatan Hayoun; Tal Shima
      Pages: 122 - 128
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Shmuel Yonatan Hayoun, Tal Shima
      A linearized endgame interception scenario along a line between a single evading target and n pursuers is considered, in which the adversaries’ controls are bounded and have arbitrary-order dynamics, and the evader’s maneuvers are not known a priori to the pursuing team. To determine the merit in utilizing multiple interceptors, in terms of their capability to impose point capture, a capturability analysis is performed, presenting necessary and sufficient conditions for the feasibility of point capture for any admissible evader maneuver. It is shown that the pursuing team is capable of guaranteeing point capture if and only if it consists of at least one pursuer capable of independently imposing point capture. This requirement is independent of the number of pursuers, leading to the conclusion that it cannot be relaxed by increasing the number of interceptors or by any manner of cooperation, in terms of coordinated motion, between the pursuers.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.054
      Issue No: Vol. 85 (2017)
  • Adaptive compensation for actuator failures with event-triggered input
    • Authors: Lantao Xing; Changyun Wen; Zhitao Liu; Hongye Su; Jianping Cai
      Pages: 129 - 136
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Lantao Xing, Changyun Wen, Zhitao Liu, Hongye Su, Jianping Cai
      In this paper, we study the problem of event-triggered control for a class of uncertain nonlinear systems subject to actuator failures. The actuator failures are allowed to be unknown and the total number of failures could be infinite. To reduce the communication burden from the controller to the actuator, a novel event-triggered control law is designed. It is proved through Lyapunov analyses that the proposed control protocol ensures that all the signals of the closed-loop system are globally bounded and the system output tracking error can exponentially converge to a residual which can be made arbitrarily small.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.061
      Issue No: Vol. 85 (2017)
  • Stabilizing tube-based model predictive control: Terminal set and cost
           construction for LPV systems
    • Authors: Jurre Hanema; Mircea Lazar; Roland Tóth
      Pages: 137 - 144
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Jurre Hanema, Mircea Lazar, Roland Tóth
      This paper presents a stabilizing tube-based MPC synthesis for LPV systems. We employ terminal constraint sets which are required to be controlled periodically contractive. Periodically (or finite-step) contractive sets are easier to compute and can be of lower complexity than “true” contractive ones, lowering the required computational effort both off-line and on-line. Under certain assumptions on the tube parameterization, recursive feasibility of the scheme is proven. Subsequently, asymptotic stability of the origin is guaranteed through the construction of a suitable terminal cost based on a novel Lyapunov-like metric for compact convex sets containing the origin. A periodic variant on the well-known homothetic tube parameterization that satisfies the necessary assumptions and yields a tractable LPV MPC algorithm is derived. The resulting MPC algorithm requires the on-line solution of a single linear program with linear complexity in the prediction horizon. The properties of the approach are demonstrated by a numerical example.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.046
      Issue No: Vol. 85 (2017)
  • A new kernel-based approach to system identification with quantized output
    • Authors: Giulio Bottegal; Håkan Hjalmarsson; Gianluigi Pillonetto
      Pages: 145 - 152
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Giulio Bottegal, Håkan Hjalmarsson, Gianluigi Pillonetto
      In this paper we introduce a novel method for linear system identification with quantized output data. We model the impulse response as a zero-mean Gaussian process whose covariance (kernel) is given by the recently proposed stable spline kernel, which encodes information on regularity and exponential stability. This serves as a starting point to cast our system identification problem into a Bayesian framework. We employ Markov Chain Monte Carlo methods to provide an estimate of the system. In particular, we design two methods based on the so-called Gibbs sampler that allow also to estimate the kernel hyperparameters by marginal likelihood maximization via the expectation–maximization method. Numerical simulations show the effectiveness of the proposed scheme, as compared to the state-of-the-art kernel-based methods when these are employed in system identification with quantized data.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.053
      Issue No: Vol. 85 (2017)
  • Time-optimal velocity tracking control for differential drive robots
    • Authors: Hasan A. Poonawala; Mark W. Spong
      Pages: 153 - 157
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Hasan A. Poonawala, Mark W. Spong
      Nonholonomic wheeled mobile robots are often required to implement control algorithms designed for holonomic kinematic systems. This creates a velocity tracking problem for an actual wheeled mobile robot. In this paper, we investigate the issue of tracking a desired velocity in the least amount of time, for a differential drive nonholonomic wheeled mobile robot with torque inputs. The Pontryagin Maximum Principle provides time-optimal controls that must be implemented as open-loop commands to the motors. We propose two discontinuous state-based feedback control laws, such that the associated closed-loop systems track a desired velocity in minimum time. The feedback control laws are rigorously shown to produce only time-optimal trajectories, by constructing a regular synthesis for each control law. The availability of these time-optimal feedback control laws makes re-computation of open-loop time-optimal controls (due to changes in the desired velocity or input disturbances) unnecessary.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.038
      Issue No: Vol. 85 (2017)
  • A data-driven approach to actuator and sensor fault detection, isolation
           and estimation in discrete-time linear systems
    • Authors: Esmaeil Naderi; K. Khorasani
      Pages: 165 - 178
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Esmaeil Naderi, K. Khorasani
      In this work, we propose and develop data-driven explicit state-space based fault detection, isolation and estimation filters that are directly identified and constructed from only the available system input–output (I/O) measurements and through only the estimated system Markov parameters. The proposed methodology does not involve a reduction step and does not require identification of the system extended observability matrix or its left null space. The performance of our proposed filters is directly related to and linearly dependent on the Markov parameters identification errors. The estimation filters operate with a subset of the system I/O data that is selected by the designer. It is shown that our proposed filters provide an asymptotically unbiased estimate by invoking a low order filter as long as the selected subsystem has a stable inverse. We have derived the estimation error dynamics in terms of the Markov parameters identification errors and have shown that they can be directly synthesized from the healthy system I/O data. Consequently, our proposed methodology ensures that the estimation errors can be effectively compensated for. Finally, we have provided several illustrative case study simulations that demonstrate and confirm the merits of our proposed schemes as compared to methodologies that are available in the literature.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.040
      Issue No: Vol. 85 (2017)
  • Distributed Nash equilibrium seeking for aggregative games with coupled
    • Authors: Shu Liang; Peng Yi; Yiguang Hong
      Pages: 179 - 185
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Shu Liang, Peng Yi, Yiguang Hong
      In this paper, we study a distributed continuous-time design for aggregative games with coupled constraints in order to seek the generalized Nash equilibrium by a group of agents via simple local information exchange. To solve the problem, we propose a distributed algorithm based on projected dynamics and non-smooth tracking dynamics, even for the case when the interaction topology of the multi-agent network is time-varying. Moreover, we prove the convergence of the non-smooth algorithm for the distributed game by taking advantage of its special structure and also combining the techniques of the variational inequality and Lyapunov function.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.064
      Issue No: Vol. 85 (2017)
  • Unknown input functional observability of descriptor systems with neutral
           and distributed delay effects
    • Authors: Francisco Javier Bejarano; Gang Zheng
      Pages: 186 - 192
      Abstract: Publication date: November 2017
      Source:Automatica, Volume 85
      Author(s): Francisco Javier Bejarano, Gang Zheng
      In this paper a general class of linear systems with time-delays is considered, which includes linear classical systems, linear systems with commensurate delays, neutral systems and singular systems with delays. After given a formal definition of functional backward observability (BO), an easily testable condition is found. The fulfillment of the obtained condition allows for the reconstruction of the trajectories of the system under consideration using the actual and past values of the system output and some of its derivatives. The methodology we follow consists in an iterative algorithm based upon the classical Silverman algorithm used for inversion of linear systems. By using basic module theory we manage to prove that the proposed algorithm is convergent. A direct application of studying functional observability is that a condition can be derived for systems with distributed delays also, we do this as a case of study. The obtained results are illustrated by two examples, one is merely academic but illustrates clearly the kind of systems which the proposed methodology works for and the other is a practical system with distributed delays.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.044
      Issue No: Vol. 85 (2017)
  • An adaptive order/state estimator for linear systems with non-integer
           time-varying order
    • Authors: S. Sepehr Tabatabaei; Heidar Ali Talebi; Mahdi Tavakoli
      Pages: 1 - 9
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): S. Sepehr Tabatabaei, Heidar Ali Talebi, Mahdi Tavakoli
      This paper proposes the design of a simultaneous order estimator and state observer for non-integer time-varying order linear systems. Several lemmas and theorems pertaining to the stability of variable order systems are provided first. Next, a theorem proposes an order/state estimator for linear variable order systems. Then, a simulation study is presented to verify the theoretical results.

      PubDate: 2017-07-12T09:27:05Z
      DOI: 10.1016/j.automatica.2017.06.042
      Issue No: Vol. 84 (2017)
  • On algorithms for state feedback stabilization of Boolean control networks
    • Authors: Jinling Liang; Hongwei Chen; Yang Liu
      Pages: 10 - 16
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Jinling Liang, Hongwei Chen, Yang Liu
      This paper deals with the algorithms for state feedback stabilization of Boolean control networks (BCNs). By resorting to the semi-tensor product (STP) technique, the labelled digraph that can be used to completely characterize the dynamics of BCNs is derived, which leads to an equivalent graphical description for the stabilization of BCNs. What is more interesting is the fact that the existence of a state feedback control law stabilizing the BCN to some given equilibrium point can be characterized in terms of its spanning in-tree. Consequently, two in-tree search algorithms, namely, the breadth-first search and the depth-first search, are proposed to design the state feedback stabilizing law when global stabilization is feasible. Besides, some basic properties about the tree-search algorithms are addressed. A biological example is employed to illustrate the applicability and usefulness of the developed algorithms.

      PubDate: 2017-07-12T09:27:05Z
      DOI: 10.1016/j.automatica.2017.06.040
      Issue No: Vol. 84 (2017)
  • A Tensor Network Kalman filter with an application in recursive MIMO
           Volterra system identification
    • Authors: Kim Batselier; Zhongming Chen; Ngai Wong
      Pages: 17 - 25
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Kim Batselier, Zhongming Chen, Ngai Wong
      This article introduces a Tensor Network Kalman filter, which can estimate state vectors that are exponentially large without ever having to explicitly construct them. The Tensor Network Kalman filter also easily accommodates the case where several different state vectors need to be estimated simultaneously. The key lies in rewriting the standard Kalman equations as tensor equations and then implementing them using Tensor Networks, which effectively transforms the exponential storage cost and computational complexity into a linear one. We showcase the power of the proposed framework through an application in recursive nonlinear system identification of high-order discrete-time multiple-input multiple-output (MIMO) Volterra systems. The identification problem is transformed into a linear state estimation problem wherein the state vector contains all Volterra kernel coefficients and is estimated using the Tensor Network Kalman filter. The accuracy and robustness of the scheme are demonstrated via numerical experiments, which show that updating the Kalman filter estimate of a state vector of length 109 and its covariance matrix takes about 0.007 s on a standard desktop computer in Matlab.

      PubDate: 2017-07-23T22:45:25Z
      DOI: 10.1016/j.automatica.2017.06.019
      Issue No: Vol. 84 (2017)
  • Tensor Network alternating linear scheme for MIMO Volterra system
    • Authors: Kim Batselier; Zhongming Chen; Ngai Wong
      Pages: 26 - 35
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Kim Batselier, Zhongming Chen, Ngai Wong
      This article introduces two Tensor Network-based iterative algorithms for the identification of high-order discrete-time nonlinear multiple-input multiple-output (MIMO) Volterra systems. The system identification problem is rewritten in terms of a Volterra tensor, which is never explicitly constructed, thus avoiding the curse of dimensionality. It is shown how each iteration of the two identification algorithms involves solving a linear system of low computational complexity. The proposed algorithms are guaranteed to monotonically converge and numerical stability is ensured through the use of orthogonal matrix factorizations. The performance and accuracy of the two identification algorithms are illustrated by numerical experiments, where accurate degree-10 MIMO Volterra models are identified in about 1 s using Matlab on a 3.3 GHz quad-core desktop computer with 16 GB RAM.

      PubDate: 2017-07-23T22:45:25Z
      DOI: 10.1016/j.automatica.2017.06.033
      Issue No: Vol. 84 (2017)
  • Function perturbations on singular Boolean networks
    • Authors: Yang Liu; Bowen Li; Hongwei Chen; Jinde Cao
      Pages: 36 - 42
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Yang Liu, Bowen Li, Hongwei Chen, Jinde Cao
      This paper is devoted to studying function perturbations on the transition matrix and topological structure of a singular Boolean network (SBN) via the semi-tensor product of matrices. First, the algebraic form of an SBN is given, and we discuss how the transition matrix of the SBN changes under function perturbations. Then the local uniqueness of solutions to the SBN is studied, under which the impacts of function perturbations on the topological structure are investigated. Finally, examples are given to show the effectiveness of the obtained results.

      PubDate: 2017-07-23T22:45:25Z
      DOI: 10.1016/j.automatica.2017.06.035
      Issue No: Vol. 84 (2017)
  • Solvability conditions and design for state synchronization of multi-agent
    • Authors: Anton A. Stoorvogel; Ali Saberi; Meirong Zhang
      Pages: 43 - 47
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Anton A. Stoorvogel, Ali Saberi, Meirong Zhang
      This paper derives conditions on the agents for the existence of a protocol which achieves synchronization of homogeneous multi-agent systems (MAS) with partial-state coupling, where the communication network is directed and weighted. These solvability conditions are necessary and sufficient for single-input agents and sufficient for multi-input agents. The solvability conditions reveal that the synchronization problem is primarily solvable for two classes of agents. This first class consists of at most weakly unstable agents (i.e. agents have all eigenvalues in the closed left half plane) and the second class consists of at most weakly non-minimum-phase agents (i.e. agents have all zeros in the closed left half plane). Under our solvability condition, we provide in this paper a design, utilizing H ∞ optimal control.

      PubDate: 2017-07-23T22:45:25Z
      DOI: 10.1016/j.automatica.2017.06.016
      Issue No: Vol. 84 (2017)
  • Adaptation, coordination, and local interactions via distributed
    • Authors: Dario Bauso
      Pages: 48 - 55
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Dario Bauso
      This paper investigates the relation between cooperation, competition, and local interactions in large distributed multi-agent systems. The main contribution is the game-theoretic problem formulation and solution approach based on the new framework of distributed approachability, and the study of the convergence properties of the resulting game model. Approachability theory is the theory of two-player repeated games with vector payoffs, and distributed approachability is here presented for the first time as an extension to the case where we have a team of agents cooperating against a team of adversaries under local information and interaction structure. The game model turns into a nonlinear differential inclusion, which after a proper design of the control and disturbance policies, presents a consensus term and an exogenous adversarial input. Local interactions enter into the model through a graph topology and the corresponding graph-Laplacian matrix. Given the above model, we turn the original questions on cooperation, competition, and local interactions, into convergence properties of the differential inclusion. In particular, we prove convergence and exponential convergence conditions around zero under general Markovian strategies. We illustrate our results in the case of decentralized organizations with multiple decision-makers.

      PubDate: 2017-07-23T22:45:25Z
      DOI: 10.1016/j.automatica.2017.06.017
      Issue No: Vol. 84 (2017)
  • Pareto suboptimal controllers in multi-objective disturbance attenuation
    • Authors: Dmitry V. Balandin; Mark M. Kogan
      Pages: 56 - 61
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Dmitry V. Balandin, Mark M. Kogan
      A multi-objective disturbance attenuation problem is considered as a novel framework for control and filtering problems under multiple exogenous disturbances. There are N potentially possible disturbance inputs of a system on each of which may act a disturbance from a certain class. A disturbance attenuation level is defined for each channel as an induced norm of the operator mapping signals of the corresponding class to the objective output of the system. Necessary conditions of the Pareto optimality are derived. It is established that the optimal solutions with respect to a multi-objective cost parameterized by weights from an N -dimensional simplex are Pareto suboptimal solutions and their relative losses compared to the Pareto optimal ones do not exceed 1 − N ∕ N . These results are extended to the case when the disturbances acting on different inputs are combined into coalitions. The approach is applied to multiple classes of L 2 -bounded and impulsive disturbances for which the H ∞ ∕ γ 0 optimal controllers as the Pareto suboptimal solutions are synthesized in terms of linear matrix inequalities (LMIs). Illustrative examples demonstrate the effectiveness of the approach proposed.

      PubDate: 2017-08-03T08:07:31Z
      DOI: 10.1016/j.automatica.2017.06.041
      Issue No: Vol. 84 (2017)
  • Moment-based analysis of stochastic hybrid systems with renewal
    • Authors: Mohammad Soltani; Abhyudai Singh
      Pages: 62 - 69
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Mohammad Soltani, Abhyudai Singh
      Stochastic Hybrid Systems (SHS) constitute an important class of mathematical models that integrate discrete stochastic events with continuous dynamics. The time evolution of statistical moments is generally not closed for SHS, in the sense that the time derivative of the lower-order moments depends on higher-order moments. Here, we identify an important class of SHS where moment dynamics is automatically closed, and hence moments can be computed exactly by solving a system of coupled differential equations. This class is referred to as linear time-triggered SHS (TTSHS), where the state evolves according to a linear dynamical system. Stochastic events occur at discrete times and the intervals between them are independent random variables that follow a general class of probability distributions. Moreover, whenever the event occurs, the state of the SHS changes randomly based on a probability distribution. Our approach relies on embedding a Markov chain based on phase-type processes to model timing of events, and showing that the resulting system has closed moment dynamics. Interestingly, we identify a subclass of linear TTSHS, where the first and second-order moments depend only on the mean time interval between events, and invariant of higher-order statistics of event timing. TTSHS are used to model examples drawn from cell biology and nanosensors, providing novel insights into how noise is regulated in these systems.

      PubDate: 2017-08-03T08:07:31Z
      DOI: 10.1016/j.automatica.2017.07.001
      Issue No: Vol. 84 (2017)
  • ℓ2-stability: The cases of infinite dimensional discrete autonomous
           systems and 2-D autonomous systems
    • Authors: Chirayu D. Athalye; Debasattam Pal; Harish K. Pillai
      Pages: 70 - 78
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Chirayu D. Athalye, Debasattam Pal, Harish K. Pillai
      In this paper, we analyze ℓ 2 -stability of infinite dimensional discrete autonomous systems given in a state space form with state transition matrix being a Laurent polynomial matrix A ( σ , σ − 1 ) in the shift operator σ . We give sufficient conditions and necessary conditions for ℓ 2 -stability of such systems. We then use the theory of ℓ 2 -stability, thus developed, to analyze ℓ 2 -stability of discrete 2-D autonomous systems. We achieve this by showing how a discrete 2-D autonomous system can be converted to an equivalent infinite dimensional state space discrete autonomous system, where the state transition matrix turns out to be a Laurent polynomial matrix in the shift operator. Finally, we provide some easy-to-check numerical tests for ℓ 2 -stability of the above-mentioned type of systems.

      PubDate: 2017-08-03T08:07:31Z
      DOI: 10.1016/j.automatica.2017.06.028
      Issue No: Vol. 84 (2017)
  • On the consensus of homogeneous multi-agent systems with arbitrarily
           switching topology
    • Authors: Maria Elena Valcher; Irene Zorzan
      Pages: 79 - 85
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Maria Elena Valcher, Irene Zorzan
      In this paper we investigate the consensus problem under arbitrary switching for homogeneous multi-agent systems with switching communication topology, by assuming that each agent is described by a single-input stabilizable state–space model and that the communication graph is connected at every time instant. Under these assumptions, we construct a common quadratic positive definite Lyapunov function for the switched system describing the evolution of the disagreement vector, thus showing that the agents always reach consensus. In addition, the proof leads to the explicit construction of a constant state-feedback matrix that allows the multi-agent system to achieve consensus.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.011
      Issue No: Vol. 84 (2017)
  • Output synchronization of heterogeneous discrete-time systems: A
           model-free optimal approach
    • Authors: Bahare Kiumarsi; Frank L. Lewis
      Pages: 86 - 94
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Bahare Kiumarsi, Frank L. Lewis
      This paper presents an optimal model-free solution to the output synchronization of heterogeneous multi-agent discrete-time systems. First, local discounted performance functions are defined for all agents and the optimal synchronization control protocols are found by solving a set of algebraic Riccati equations (AREs) and without requiring the explicit solution to the output regulator equations. It is shown that the proposed method implicitly solves the output regulator equations and therefore solves the output synchronization problem, provided that the discount factor is bigger than a lower bound. This formulation enables us to develop a Q -learning algorithm to solve the AREs using only measured data and so find the optimal distributed control protocols for each agent without requiring complete knowledge of the agents’ or leader’s dynamics. It is shown that the combination of a distributed adaptive observer and the controller guarantees synchronization. The relationship between the standard solution and the proposed solution is also shown. A simulation example is given to show the effectiveness of the proposed method.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.004
      Issue No: Vol. 84 (2017)
  • Finite-time boundary stabilization of general linear hyperbolic balance
           laws via Fredholm backstepping transformation
    • Authors: Jean-Michel Coron; Long Hu; Guillaume Olive
      Pages: 95 - 100
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Jean-Michel Coron, Long Hu, Guillaume Olive
      This paper is devoted to a simple and new proof on the optimal finite control time for general linear coupled hyperbolic system by using boundary feedback on one side. The feedback control law is designed by first using a Volterra transformation of the second kind and then using an invertible Fredholm transformation. Both existence and invertibility of the transformations are easily obtained.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.05.013
      Issue No: Vol. 84 (2017)
  • Simulation budget allocation for simultaneously selecting the best and
           worst subsets
    • Authors: Hui Xiao; Siyang Gao; Loo Hay Lee
      Pages: 117 - 127
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Hui Xiao, Siyang Gao, Loo Hay Lee
      Motivated by the practical needs in simulation optimization, this paper considers the problem of selecting the best m and worst n designs from a total of k alternatives based on their mean performance values, which are unknown and can only be estimated via simulation. In order to improve the efficiency of simulation, this research characterizes an asymptotically optimal allocation of simulation replications among the k designs such that the probability of correctly selecting the best m and worst n designs can be maximized, and develops a corresponding selection procedure for implementation purpose. The efficiency of the proposed procedure is demonstrated via numerical experiments.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.006
      Issue No: Vol. 84 (2017)
  • Controller–jammer game models of Denial of Service in control systems
           operating over packet-dropping links
    • Authors: Valery Ugrinovskii; Cedric Langbort
      Pages: 128 - 141
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Valery Ugrinovskii, Cedric Langbort
      The paper introduces a class of zero-sum games between the adversary and controller as a scenario for a ‘denial of service’ in a networked control system. The communication link is modelled as a set of transmission regimes controlled by a strategic jammer whose intention is to wage an attack on the plant by choosing a most damaging regime-switching strategy. We demonstrate that even in the one-step case, the introduced games admit a saddle-point equilibrium, at which the jammer’s optimal policy is to randomize in a region of the plant’s state space, thus requiring the controller to undertake a nontrivial response which is different from what one would expect in a standard stochastic control problem over a packet dropping link. The paper derives conditions for the introduced games to have such a saddle-point equilibrium. Furthermore, we show that in more general multi-stage games, these conditions provide ‘greedy’ jamming strategies for the adversary.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.009
      Issue No: Vol. 84 (2017)
  • Dual decomposition for multi-agent distributed optimization with coupling
    • Authors: Alessandro Falsone; Kostas Margellos; Simone Garatti; Maria Prandini
      Pages: 149 - 158
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Alessandro Falsone, Kostas Margellos, Simone Garatti, Maria Prandini
      We study distributed optimization in a cooperative multi-agent setting, where agents have to agree on the usage of shared resources and can communicate via a time-varying network to this purpose. Each agent has its own decision variables that should be set so as to minimize its individual objective function subject to local constraints. Resource sharing is modeled via coupling constraints that involve the non-positivity of the sum of agents’ individual functions, each one depending on the decision variables of one single agent. We propose a novel distributed algorithm to minimize the sum of the agents’ objective functions subject to both local and coupling constraints, where dual decomposition and proximal minimization are combined in an iterative scheme. Notably, privacy of information is guaranteed since only the dual optimization variables associated with the coupling constraints are exchanged by the agents. Under convexity assumptions, jointly with suitable connectivity properties of the communication network, we are able to prove that agents reach consensus to some optimal solution of the centralized dual problem counterpart, while primal variables converge to the set of optimizers of the centralized primal problem. The efficacy of the proposed approach is demonstrated on a plug-in electric vehicles charging problem.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.003
      Issue No: Vol. 84 (2017)
  • Optimal network design for synchronization of coupled oscillators
    • Authors: Mahyar Fazlyab; Florian Dörfler; Victor M. Preciado
      Pages: 181 - 189
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Mahyar Fazlyab, Florian Dörfler, Victor M. Preciado
      This paper studies the problem of designing networks of nonidentical coupled oscillators in order to achieve a desired level of phase cohesiveness, defined as the maximum asymptotic phase difference across the edges of the network. In particular, we consider the following two design problems: (i) the nodal-frequency design problem, in which we tune the natural frequencies of the oscillators given the topology of the network, and (ii) the (robust) edge-weight design problem, in which we design the edge weights assuming that the natural frequencies are given (or belong to a given convex uncertainty set). For both problems, we optimize an objective function of the design variables while considering a desired level of phase cohesiveness as our design constraint. This constraint defines a convex set in the nodal-frequency design problem. In contrast, in the edge-weight design problem, the phase cohesiveness constraint yields a non-convex set, unless the underlying network is either a tree or an arbitrary graph with identical edge weights. We then propose a convex semidefinite relaxation to approximately solve the (non-convex) edge-weight design problem for general (possibly cyclic) networks with nonidentical edge weights. We illustrate the applicability of our results by analyzing several network design problems of practical interest, such as power redispatch in power grids, sparse network design, (robust) network design for distributed wireless analog clocks, and the detection of edges leading to the Braess’ paradox in power grids.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.005
      Issue No: Vol. 84 (2017)
  • Discrimination of singleton and periodic attractors in Boolean networks
    • Authors: Xiaoqing Cheng; Takeyuki Tamura; Wai-Ki Ching; Tatsuya Akutsu
      Pages: 205 - 213
      Abstract: Publication date: October 2017
      Source:Automatica, Volume 84
      Author(s): Xiaoqing Cheng, Takeyuki Tamura, Wai-Ki Ching, Tatsuya Akutsu
      Determining the minimum number of sensor nodes to observe the internal state of the whole system is important in analysis of complex networks. However, existing studies suggest that a large number of sensor nodes are needed to know the whole internal state. In this paper, we focus on identification of a small set of sensor nodes to discriminate statically and periodically steady states using the Boolean network model where steady states are often considered to correspond to cell types. In other words, we seek a minimum set of nodes to discriminate singleton and periodic attractors. We prove that one node is not necessarily enough but two nodes are always enough to discriminate two periodic attractors by using the Chinese remainder theorem. Based on this, we present an algorithm to determine the minimum number of nodes to discriminate all given attractors. We also present a much more efficient algorithm to discriminate singleton attractors. The results of computational experiments suggest that attractors in realistic Boolean networks can be discriminated by observing the states of only a small number of nodes.

      PubDate: 2017-09-02T16:13:56Z
      DOI: 10.1016/j.automatica.2017.07.012
      Issue No: Vol. 84 (2017)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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