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  Subjects -> COMPUTER SCIENCE (Total: 1996 journals)
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COMPUTER SCIENCE (1162 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: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 23)
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: 12)
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: 14)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 5)
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: 21)
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: 9)
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: 25)
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: 9)
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: 14)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
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: 39)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 3)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 8)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 9)
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: 5)
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: 11)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 7)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
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: 1)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 13)
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: 33)
Applied Medical Informatics     Open Access   (Followers: 11)
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: 134)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 7)
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   (Followers: 1)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 4)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 11)
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)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 270)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 33)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 128)
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)
Capturing Intelligence     Full-text available via subscription  
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
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: 14)
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: 12)
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: 54)
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: 11)
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: 15)
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: 30)
Computer     Full-text available via subscription   (Followers: 87)
Computer Aided Surgery     Hybrid Journal   (Followers: 3)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 7)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 8)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 21)
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: 12)
Computer Science Education     Hybrid Journal   (Followers: 13)
Computer Science Journal     Open Access   (Followers: 20)

        1 2 3 4 5 6 | Last

Journal Cover Automatica
  [SJR: 4.315]   [H-I: 188]   [11 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0005-1098
   Published by Elsevier Homepage  [3089 journals]
  • Stubborn state observers for linear time-invariant systems
    • Authors: Angelo Alessandri; Luca Zaccarian
      Pages: 1 - 9
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Angelo Alessandri, Luca Zaccarian
      For the purpose of estimating the state of a linear time-invariant system with measurements subject to outliers, we propose an observer with a saturated output injection in such a way to mitigate the effect of abnormal and isolated measurement noise on the error dynamics. Stability conditions in both the continuous-time and the discrete-time cases are derived, which ensure global exponential stability to the origin for the error dynamics. Such conditions can be expressed in terms of linear matrix inequalities, allowing for a viable design by using convex optimization. The effectiveness of the approach is illustrated by means of simulations in comparison with the Luenberger observer.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.10.022
      Issue No: Vol. 88 (2017)
       
  • Lyapunov small-gain theorems for networks of not necessarily ISS hybrid
           systems
    • Authors: Andrii Mironchenko; Guosong Yang; Daniel Liberzon
      Pages: 10 - 20
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Andrii Mironchenko, Guosong Yang, Daniel Liberzon
      We prove a novel Lyapunov-based small-gain theorem for networks composed of n ≥ 2 hybrid subsystems which are not necessarily input-to-state stable. This result unifies and extends several small-gain theorems for hybrid and impulsive systems proposed in the last few years. We also show how average dwell-time (ADT) clocks and reverse ADT clocks can be used to modify the ISS Lyapunov functions for subsystems and to enlarge the applicability of the derived small-gain theorems.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.10.020
      Issue No: Vol. 88 (2017)
       
  • Global stabilization of feedforward nonlinear time-delay systems by
           bounded controls
    • Authors: Bin Zhou; Xuefei Yang
      Pages: 21 - 30
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Bin Zhou, Xuefei Yang
      The problem of global stabilization for a family of feedforward nonlinear time-delay systems by bounded controls is considered. Based on a special canonical form of the considered nonlinear system, two types of new nonlinear control laws are proposed to achieve global stabilization. The new special canonical form used in this paper contains not only time delay in the input but also time delays in the state, which leads to natural cancellation in the recursive design. Moreover, some free parameters are introduced into these controllers. These advantages can help to simplify the proof for the global stability of the closed-loop system and improve the transient performance of the closed-loop system significantly. A practical example is given to illustrate the effectiveness of the proposed approaches.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.10.021
      Issue No: Vol. 88 (2017)
       
  • An incremental harmonic balance-based approach for harmonic analysis of
           closed-loop systems with Prandtl–Ishlinskii operator
    • Authors: Lei Fang; Jiandong Wang; Xiaobo Tan
      Pages: 48 - 56
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Lei Fang, Jiandong Wang, Xiaobo Tan
      Analyzing hysteretic systems presents a significant challenge due to the memory effect of hysteresis. In this paper we present an incremental harmonic balance (IHB)-based approach to compute the steady-state response of a closed-loop system with hysteresis under a sinusoidal excitation, where the hysteresis element is modeled by the Prandtl–Ishlinskii (PI) operator. While the describing function method (DFM) can be used to obtain an approximate solution for the closed-loop system based on first-order harmonics, the proposed IHB-based approach iteratively calculates the harmonic components of the hysteretic system up to an arbitrary order. The main challenge is the harmonic calculation of the periodic output of the PI operator for a multi-harmonic input. In order to address this problem, an alternative definition of the play operator is utilized as the hysteron for the PI operator. By using the alternative definition, a set of switching time instants, when the play operator enters or exits the boundary region, are determined by a bisection method. The calculation of the incremental harmonic components is finally reformulated as a linear matrix equality that can be solved efficiently. As an illustration, numerical results for a system involving a proportional–integral feedback controller are presented to demonstrate the advantage of the IHB-based approach over the DFM in approximating the harmonic response of the hysteretic system.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.11.005
      Issue No: Vol. 88 (2017)
       
  • Optimal communication scheduling and remote estimation over an additive
           noise channel
    • Authors: Xiaobin Gao; Emrah Akyol; Tamer Başar
      Pages: 57 - 69
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Xiaobin Gao, Emrah Akyol, Tamer Başar
      This paper considers a sequential sensor scheduling and remote estimation problem with one sensor and one estimator. The sensor makes sequential observations about the state of an underlying memoryless stochastic process, and makes a decision as to whether or not to send this measurement to the estimator. The sensor and the estimator have the common objective of minimizing expected distortion in the estimation of the state of the process, over a finite time horizon. The sensor is either charged a cost for each transmission or constrained on transmission times. As opposed to the prior work where communication between the sensor and the estimator was assumed to be perfect (noiseless), in this work an additive noise channel with fixed power constraint is considered; hence, the sensor has to encode its message before transmission. Under some technical assumptions, we obtain the optimal encoding and estimation policies within the piecewise affine class in conjunction with the optimal transmission schedule. The impact of the presence of a noisy channel is analyzed numerically based on dynamic programming. This analysis yields some rather surprising results such as a phase-transition phenomenon in the number of used transmission opportunities, which was not encountered in the noiseless communication setting.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.10.010
      Issue No: Vol. 88 (2017)
       
  • Distributed Nash equilibrium seeking in networked graphical games
    • Authors: Farzad Salehisadaghiani; Lacra Pavel
      Pages: 17 - 24
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Farzad Salehisadaghiani, Lacra Pavel
      This paper considers a gossip approach for finding a Nash equilibrium in networked games on graphs, where a player’s cost function may be affected by the actions of any subset of players. An interference graph illustrates the partially-coupled cost functions, i.e., the asymmetric strategic interaction and information requirements. An algorithm is proposed whereby players make decisions based only on the estimates of their interfering players’ actions. Given the interference graph (not necessarily complete), a communication graph is designed so that players exchange only their required information. When the interference graph is sparse, the algorithm can offer substantial savings in communication and computation. Almost sure convergence to a Nash equilibrium is proved for diminishing step sizes. The effect of the second largest eigenvalue of the expected communication matrix on the convergence rate is quantified.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.016
      Issue No: Vol. 87 (2017)
       
  • A system of quaternary coupled Sylvester-type real quaternion matrix
           equations
    • Authors: Zhuo-Heng He; Qing-Wen Wang; Yang Zhang
      Pages: 25 - 31
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Zhuo-Heng He, Qing-Wen Wang, Yang Zhang
      In this paper we establish some necessary and sufficient solvability conditions for a system of quaternary coupled Sylvester-type real quaternion matrix equations in terms of ranks and generalized inverses of matrices. An expression of the general solution to this system is given when it is solvable. Also, a numerical example is presented to illustrate the main result of this paper. The findings of this paper widely generalize the known results in the literature. The main results are also valid over the real number field and the complex number field.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.008
      Issue No: Vol. 87 (2017)
       
  • Strong stability of a class of difference equations of continuous time and
           structured singular value problem
    • Authors: Qian Ma; Keqin Gu; Narges Choubedar
      Pages: 32 - 39
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Qian Ma, Keqin Gu, Narges Choubedar
      This article studies the strong stability of scalar difference equations of continuous time in which the delays are sums of a number of independent parameters τ i , i = 1 , 2 , … , K . The characteristic quasipolynomial of such an equation is a multilinear function of e − τ i s . It is known that the characteristic quasipolynomial of any difference equation set in the form of one-delay-per-scalar-channel (ODPSC) model is also in such a multilinear form. However, it is shown in this article that some multilinear forms of quasipolynomials are not characteristic quasipolynomials of any ODPSC difference equation set. The equivalence between local strong stability, the exponential stability of a fixed set of rationally independent delays, and the stability for all positive delays is shown, and relations with the structured singular value problem are presented. A procedure to determine strong stability in the special case of up to three independent delay parameters in finite steps is developed. This procedure means that the structured singular value problem in the case of up to three scalar complex uncertain blocks can be solved in finite steps.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.012
      Issue No: Vol. 87 (2017)
       
  • Sparse and constrained stochastic predictive control for networked systems
    • Authors: Prabhat K. Mishra; Debasish Chatterjee; Daniel E. Quevedo
      Pages: 40 - 51
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Prabhat K. Mishra, Debasish Chatterjee, Daniel E. Quevedo
      This article presents a novel class of control policies for networked control of Lyapunov-stable linear systems with bounded inputs. The control channel is assumed to have i.i.d. Bernoulli packet dropouts and the system is assumed to be affected by additive stochastic noise. Our proposed class of policies is affine in the past dropouts and saturated values of the past disturbances. We further consider a regularization term in a quadratic performance index to promote sparsity in control. We demonstrate how to augment the underlying optimization problem with a constant negative drift constraint to ensure mean-square boundedness of the closed-loop states, yielding a convex quadratic program to be solved periodically online. The states of the closed-loop plant under the receding horizon implementation of the proposed class of policies are mean square bounded for any positive bound on the control and any non-zero probability of successful transmission.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.013
      Issue No: Vol. 87 (2017)
       
  • Finite-time and fixed-time observer design: Implicit Lyapunov function
           approach
    • Authors: Francisco Lopez-Ramirez; Andrey Polyakov; Denis Efimov; Wilfrid Perruquetti
      Pages: 52 - 60
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Francisco Lopez-Ramirez, Andrey Polyakov, Denis Efimov, Wilfrid Perruquetti
      This work deals with the problem of finite-time and fixed-time observation of linear multiple input multiple output (MIMO) control systems. The proposed nonlinear dynamic observers guarantee convergence of the observer states to the original system state in a finite and in a fixed (defined a priori) time. Algorithms for the observers parameters tuning are also provided and a robustness analysis against input disturbances and measurement noises is carried out. The theoretical results are illustrated by numerical examples that consider both noisy and noise-free measurements and a comparison with a high-gain observer is included.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.007
      Issue No: Vol. 87 (2017)
       
  • Model predictive control of constrained Markovian jump nonlinear
           stochastic systems and portfolio optimization under market frictions
    • Authors: Vladimir Dombrovskii; Tatiana Obyedko; Maria Samorodova
      Pages: 61 - 68
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Vladimir Dombrovskii, Tatiana Obyedko, Maria Samorodova
      In this paper we consider MPC for a class of constrained discrete-time Markovian switching systems consisting of a family of nonlinear stochastic subsystems whose nonlinear stochastic term for a particular mode is described by its statistical properties. The additive nonlinearity of the subsystems is allowed to contain state, input, and independent noise vectors. It is allowed so that hard constraints are imposed on the input manipulated variables. The results obtained are applied to the dynamic investment portfolio selection problem for a financial market with switching modes subject to hard constraints on trading amounts taking into account the presence of market frictions. Our approach is tested on a set of real data from the Russian Stock Exchange MICEX.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.018
      Issue No: Vol. 87 (2017)
       
  • Adaptive control of linear 2×2 hyperbolic systems
    • Authors: Henrik Anfinsen; Ole Morten Aamo
      Pages: 69 - 82
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Henrik Anfinsen, Ole Morten Aamo
      We design two closely related state feedback adaptive control laws for stabilization of a class of 2 × 2 linear hyperbolic system of partial differential equations (PDEs) with constant but uncertain in-domain and boundary parameters. One control law uses an identifier, while the other is based on swapping design. We establish boundedness of all signals in the closed loop system, pointwise in space and time, and convergence of the system states to zero pointwise in space. The theory is demonstrated in simulations.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.020
      Issue No: Vol. 87 (2017)
       
  • Adaptive control-based Barrier Lyapunov Functions for a class of
           stochastic nonlinear systems with full state constraints
    • Authors: Yan-Jun Liu; Shumin Lu; Shaocheng Tong; Xinkai Chen; C.L. Philip Chen; Dong-Juan Li
      Pages: 83 - 93
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Yan-Jun Liu, Shumin Lu, Shaocheng Tong, Xinkai Chen, C.L. Philip Chen, Dong-Juan Li
      An adaptive control scheme is developed in the paper for nonlinear stochastic systems with unknown parameters. All the states in the systems are required to be constrained in a bounded compact set, i.e., the full state constraints are considered in the systems. It is for the first time to control nonlinear stochastic systems with the full state constraints. In contrast to deterministic systems, the stochastic systems with the full state constraints are more difficult to be stabilized and the design procedures are more complicated. By constructing Barrier Lyapunov Functions (BLF) in symmetric and asymmetric forms, it can be ensured that all the states of the stochastic systems are not to transgress their constraint bounds. Thus, the proposed scheme not only solves the stability problem of stochastic systems, but also overcomes the effect of the full state constraints on the control performance. Finally, it is proved that all the signals in the closed-loop system are semi-global uniformly ultimately bounded (SGUUB) in probability, the system output is driven to follow the reference signals, and all the states are ensured to remain in the predefined compact sets. The validity of the proposed scheme is verified by a simulation example.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.07.028
      Issue No: Vol. 87 (2017)
       
  • Negotiated distributed estimation with guaranteed performance for
           bandwidth-limited situations
    • Authors: Luis Orihuela; Pablo Millán; Samira Roshany-Yamchi; Ramón A. García
      Pages: 94 - 102
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Luis Orihuela, Pablo Millán, Samira Roshany-Yamchi, Ramón A. García
      This paper proposes a guaranteed distributed estimator for large-scale, state-coupled plants. Each agent must find appropriate sets, described by zonotopes, to contain the actual state of the plant and reduce the estimation uncertainties. To do so, the agents collaborate by sending information through a network in which bandwidth restrictions need to be taken into account. An estimation algorithm is proposed, where the amount of information transmitted is negotiated through an iterative procedure that trades off communication burden and estimation performance. The negotiation process between the agents is similar to a non-cooperative game, which ends when the Nash equilibrium is reached. The algorithm can be tuned to weight estimation performance, communication costs, and discrepancies in the amount of information transmitted by neighboring agents. The estimation structure is tested by simulation on a plant consisting of a set of inverted pendulums coupled by springs.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.022
      Issue No: Vol. 87 (2017)
       
  • A hybrid fixed-time observer for state estimation of linear systems
    • Authors: Héctor Ríos; Andrew R. Teel
      Pages: 103 - 112
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Héctor Ríos, Andrew R. Teel
      This paper deals with the problem of state estimation for single-output linear systems. Under some structural properties of the system matrices it is possible to design a hybrid observer capable of estimating the state of the system exactly and in a finite time. Moreover, the proposed hybrid observer provides fixed-time convergence of the state estimation error, i.e. there exists a convergence time that is bounded and such a bound is independent of the initial estimation error. The robustness properties of the hybrid observer are analyzed for the linear system with unknown inputs, and the linear system with unknown inputs and parametric uncertainty. Some simulation results illustrate the effectiveness of the proposed hybrid observer.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.019
      Issue No: Vol. 87 (2017)
       
  • Leader-following control of high-order multi-agent systems under directed
           graphs: Pre-specified finite time approach
    • Authors: Yujuan Wang; Yongduan Song
      Pages: 113 - 120
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Yujuan Wang, Yongduan Song
      In this work we address the full state finite-time distributed consensus control problem for high-order multi-agent systems (MAS) under directed communication topology. Existing protocols for finite time consensus of MAS are normally based on the signum function or fractional power state feedback, and the finite convergence time is contingent upon the initial conditions and other design parameters. In this paper, by using regular local state feedback only, we present a distributed and smooth finite time control scheme to achieve leader–follower consensus under the communication topology containing a directed spanning tree. The proposed control consists of a finite time observer and a finite time compensator. The salient feature of the proposed method is that both the finite time intervals for observing leader states and for reaching consensus are independent of initial conditions and any other design parameters, thus can be explicitly pre-specified. Leader-following problem of MAS with both single and multiple leaders are studied.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.017
      Issue No: Vol. 87 (2017)
       
  • Switch observability for switched linear systems
    • Authors: Ferdinand Küsters; Stephan Trenn
      Pages: 121 - 127
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Ferdinand Küsters, Stephan Trenn
      Mode observability of switched systems requires observability of each individual mode. We consider other concepts of observability that do not have this requirement: Switching time observability and switch observability. The latter notion is based on the assumption that at least one switch occurs. These concepts are analyzed and characterized both for homogeneous and inhomogeneous systems.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.024
      Issue No: Vol. 87 (2017)
       
  • A bias-correction method for closed-loop identification of Linear
           Parameter-Varying systems
    • Authors: Manas Mejari; Dario Piga; Alberto Bemporad
      Pages: 128 - 141
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Manas Mejari, Dario Piga, Alberto Bemporad
      Due to safety constraints and unstable open-loop dynamics, system identification of many real-world processes often requiresgathering data from closed-loop experiments. In this paper, we present a bias-correction scheme for closed-loop identification of Linear Parameter-Varying Input–Output (LPV-IO) models, which aims at correcting the bias caused by the correlation between the input signal exciting the process and output noise. The proposed identification algorithm provides a consistent estimate of the open-loop model parameters when both the output signal and the scheduling variable are corrupted by measurement noise. The effectiveness of the proposed methodology is tested in two simulation case studies.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.014
      Issue No: Vol. 87 (2017)
       
  • State estimation under false data injection attacks: Security analysis and
           system protection
    • Authors: Liang Hu; Zidong Wang; Qing-Long Han; Xiaohui Liu
      Pages: 176 - 183
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Liang Hu, Zidong Wang, Qing-Long Han, Xiaohui Liu
      The security issue in the state estimation problem is investigated for a networked control system (NCS). The communication channels between the sensors and the remote estimator in the NCS are vulnerable to attacks from malicious adversaries. The false data injection attacks are considered. The aim of this paper to find the so-called insecurity conditions under which the estimation system is insecure in the sense that there exist malicious attacks that can bypass the anomaly detector but still lead to unbounded estimation errors. In particular, a new necessary and sufficient condition for the insecurity is derived in the case that all communication channels are compromised by the adversary. Moreover, a specific algorithm is proposed for generating attacks with which the estimation system is insecure. Furthermore, for the insecure system, a system protection scheme through which only a few (rather than all) communication channels require protection against false data injection attacks is proposed. A simulation example is utilized to demonstrate the effectiveness of the proposed conditions/algorithms in the secure estimation problem for a flight vehicle.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.028
      Issue No: Vol. 87 (2017)
       
  • Attack allocation on remote state estimation in multi-systems: Structural
           results and asymptotic solution
    • Authors: Xiaoqiang Ren; Junfeng Wu; Subhrakanti Dey; Ling Shi
      Pages: 184 - 194
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Xiaoqiang Ren, Junfeng Wu, Subhrakanti Dey, Ling Shi
      This paper considers optimal attack attention allocation on remote state estimation in multi-systems. Suppose there are M independent systems, each of which has a remote sensor monitoring the system and sending its local estimates to a fusion center over a packet-dropping channel. An attacker may generate noises to exacerbate the communication channels between sensors and the fusion center. Due to capacity limitation, at each time the attacker can exacerbate at most N of the M channels. The goal of the attacker side is to seek an optimal policy maximizing the estimation error at the fusion center. The problem is formulated as a Markov decision process (MDP) problem, and the existence of an optimal deterministic and stationary policy is proved. We further show that the optimal policy has a threshold structure, by which the computational complexity is reduced significantly. Based on the threshold structure, a myopic policy is proposed for homogeneous models and its optimality is established. To overcome the curse of dimensionality of MDP algorithms for general heterogeneous models, we further provide an asymptotically (as M and N go to infinity) optimal solution, which is easy to compute and implement. Numerical examples are given to illustrate the main results.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.021
      Issue No: Vol. 87 (2017)
       
  • On robustness analysis of linear vibrational control systems
    • Authors: Xiaoxiao Cheng; Ying Tan; Iven Mareels
      Pages: 202 - 209
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Xiaoxiao Cheng, Ying Tan, Iven Mareels
      By injecting high frequency dither signals, it is possible to stabilize an inverted pendulum without any feedback. The concept of the vibrational control system is thus proposed to provide extra design freedom in stabilization or other performance indexes. Although various vibrational control algorithms have been proposed and implemented in literature, little work has been done to show their robustness with respect to disturbances and uncertainties. This paper focuses on the robustness analysis of linear vibrational control systems with additive disturbances. By applying perturbation techniques, the linear vibrational control system is shown to be input-to-state stable with respect to disturbances. When disturbances are periodic, frequency analysis technique obtains a less conservative estimate of the ultimate bound of the system, indicating that disturbances with high frequencies lead to relatively small ultimate bounds. When additive state-dependent disturbances are considered, weak averaging techniques can be used to show the robustness of the system when bounded disturbances are slow time-varying. Numerical results support the theoretic analysis.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.09.029
      Issue No: Vol. 87 (2017)
       
  • Output feedback stabilization of the Korteweg–de Vries equation
    • Authors: Swann Marx; Eduardo Cerpa
      Pages: 210 - 217
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Swann Marx, Eduardo Cerpa
      This paper presents an output feedback control law for the Korteweg–de Vries equation. The control design is based on the backstepping method and the introduction of an appropriate observer. The local exponential stability of the closed-loop system is proven. Some numerical simulations are shown to illustrate this theoretical result.

      PubDate: 2017-10-25T19:02:33Z
      DOI: 10.1016/j.automatica.2017.07.057
      Issue No: Vol. 87 (2017)
       
  • Robustness analysis of a maximum correntropy framework for linear
           regression
    • Authors: Laurent Bako
      Pages: 218 - 225
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Laurent Bako
      In this paper we formulate a solution of the robust linear regression problem in a general framework of correntropy maximization. Our formulation yields a unified class of estimators which includes the Gaussian and Laplacian kernel-based correntropy estimators as special cases. An analysis of the robustness properties is then provided. The analysis includes a quantitative characterization of the informativity degree of the regression which is appropriate for studying the stability of the estimator. Using this tool, a sufficient condition is expressed under which the parametric estimation error is shown to be bounded. Explicit expression of the bound is given and discussion on its numerical computation is supplied. For illustration purpose, two special cases are numerically studied.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.09.006
      Issue No: Vol. 87 (2017)
       
  • Sampled-data boundary feedback control of 1-D parabolic PDEs
    • Authors: Iasson Karafyllis; Miroslav Krstic
      Pages: 226 - 237
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Iasson Karafyllis, Miroslav Krstic
      The paper provides results for the application of boundary feedback control with Zero-Order-Hold (ZOH) to 1-D linear parabolic systems on bounded domains. It is shown that the continuous-time boundary feedback applied in a sample-and-hold fashion guarantees closed-loop exponential stability, provided that the sampling period is sufficiently small. Two different continuous-time feedback designs are considered: the reduced model design and the backstepping design. The obtained results provide stability estimates for weighted 2-norms of the state and robustness with respect to perturbations of the sampling schedule is guaranteed.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.006
      Issue No: Vol. 87 (2017)
       
  • Particle filters for partially-observed Boolean dynamical systems
    • Authors: Mahdi Imani; Ulisses M. Braga-Neto
      Pages: 238 - 250
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Mahdi Imani, Ulisses M. Braga-Neto
      Partially-observed Boolean dynamical systems (POBDS) are a general class of nonlinear models with application in estimation and control of Boolean processes based on noisy and incomplete measurements. The optimal minimum mean square error (MMSE) algorithms for POBDS state estimation, namely, the Boolean Kalman filter (BKF) and Boolean Kalman smoother (BKS), are intractable in the case of large systems, due to computational and memory requirements. To address this, we introduce approximate MMSE filtering and smoothing algorithms based on the auxiliary particle filter (APF) method, which are called APF–BKF and APF–BKS, respectively. For joint state and parameter estimation, the APF–BKF is used jointly with maximum-likelihood (ML) methods for simultaneous state and parameter estimation in POBDS models. In the case the unknown parameters are discrete, the proposed ML adaptive filter consists of multiple APF–BKFs running in parallel, in a manner reminiscent of the Multiple Model Adaptive Estimation (MMAE) method in classical linear filtering theory. In the presence of continuous parameters, the proposed ML adaptive filter is based on an efficient particle-based expectation maximization (EM) algorithm for the POBDS model, which is based on a modified Forward Filter Backward Simulation (FFBSi) in combination with the APF–BKS. The performance of the proposed particle-based adaptive filters is assessed through numerical experiments using a POBDS model of the well-known cell cycle gene regulatory network observed through noisy RNA-Seq time series data.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.009
      Issue No: Vol. 87 (2017)
       
  • Dynamics of delayed switched nonlinear systems with applications to
           cascade systems
    • Authors: Xingwen Liu; Shouming Zhong; Qianchuan Zhao
      Pages: 251 - 257
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Xingwen Liu, Shouming Zhong, Qianchuan Zhao
      This paper addresses the dynamic properties of a class of continuous-time switched nonlinear systems with perturbations and delays. With the assumption that the nominal system is exponentially stable, it is shown that the trajectory of the perturbed system exponentially decays to or asymptotically approaches origin provided that the perturbation exponentially decays to or asymptotically approaches origin. These properties are then applied to cascade systems for their stability analysis. It is proven that a delayed switched nonlinear cascade system is exponentially stable if and only if all subsystems obtained from the cascade system by deleting the coupling terms are exponentially stable. A sufficient condition ensuring asymptotic stability of a cascade system is also proposed.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.012
      Issue No: Vol. 87 (2017)
       
  • Optimal identification experiment design for LPV systems using the local
           approach
    • Authors: Debarghya Ghosh; Xavier Bombois; Julien Huillery; Gérard Scorletti; Guillaume Mercère
      Pages: 258 - 266
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Debarghya Ghosh, Xavier Bombois, Julien Huillery, Gérard Scorletti, Guillaume Mercère
      In this paper, we consider the problem of optimally designing the experimental conditions for LPV system identification with the local approach. Such an LPV system identification experiment is characterized by a number of local LTI identification experiments performed at constant values of the scheduling variable. The main contribution of this paper is to determine these constant values of the scheduling variable as well as the input spectra of the corresponding local LTI identification experiments in order to obtain a user-defined model accuracy with the least input energy.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.013
      Issue No: Vol. 87 (2017)
       
  • Robust stability of uncertain linear systems with input and output
           quantization and packet loss
    • Authors: Lanlan Su; Graziano Chesi
      Pages: 267 - 273
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Lanlan Su, Graziano Chesi
      This paper investigates the robust stability of uncertain discrete-time linear systems subject to input and output quantization and packet loss. First, a necessary and sufficient condition in terms of LMIs is proposed for the quadratic stability of the closed-loop system with double quantization and norm bounded uncertainty in the plant. Moreover, it is shown that the proposed condition can be exploited to derive the coarsest logarithmic quantization density under which the uncertain plant can be quadratically stabilized via quantized state feedback. Second, a new class of Lyapunov function which depends on the quantization errors in a multilinear way is developed to obtain less conservative results. Lastly, the case with input and output packet-loss channels is investigated.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.014
      Issue No: Vol. 87 (2017)
       
  • Markov inequality rule for switching among time optimal controllers in a
           multiple vehicle intercept problem
    • Authors: Dejan Milutinović; David W. Casbeer; Meir Pachter
      Pages: 274 - 280
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Dejan Milutinović, David W. Casbeer, Meir Pachter
      In this paper, a Markov inequality based switching rule is proposed to switch among numerically computed, time optimal controllers in a multiple vehicle intercept problem. Each controller is optimal for the intercept of a single vehicle, i.e., for the segment of the complete time varying multiple vehicle target set. The switching rule guarantees that after every switch the time to the target set is shorter with a certain predefined probability. Furthermore, the rule guarantees that the target set is reached after a finite number of switches and the rule scales well with the number of vehicles, i.e., the segments covering the target set. The problem and results are illustrated by a numerical example.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.09.009
      Issue No: Vol. 87 (2017)
       
  • Stabilization of coupled linear heterodirectional hyperbolic PDE–ODE
           systems
    • Authors: Florent Di Meglio; Federico Bribiesca Argomedo; Long Hu; Miroslav Krstic
      Pages: 281 - 289
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Florent Di Meglio, Federico Bribiesca Argomedo, Long Hu, Miroslav Krstic
      We solve the problem of stabilizing a linear ODE having a system of a linearly coupled hyperbolic PDEs in the actuating path. The control design is based on a backstepping approach and yields exponential closed-loop stability of the zero equilibrium. The existence of a Volterra transformation relies on a relatively general well-posedness result for hyperbolic backstepping kernel equations.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.09.027
      Issue No: Vol. 87 (2017)
       
  • Symbolic reachability analysis and maximally permissive entrance control
           for globally synchronized templates
    • Authors: Liyong Lin; Alin Stefanescu; Weilin Wang; Rong Su; W. Murray Wonham
      Pages: 290 - 300
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Liyong Lin, Alin Stefanescu, Weilin Wang, Rong Su, W. Murray Wonham
      This paper studies the symbolic reachability relations of a class of parameterized systems in the framework of regular model checking. The modules of each system are instantiated from a globally synchronized template, and each globally synchronized template is represented by a finite state automaton whose event set consists of global events and local events. It is shown that the symbolic reachability relations of these systems are effectively iteration-closed star languages. And for any iteration-closed star language, there exists a template with only global events that realizes it. Application of the symbolic reachability analysis to computing the entrance control functions that enforce deadlock freeness and blocking freeness is then illustrated for systems with idle modules. In particular, we show that the maximally permissive entrance control functions can be encoded using finite state automata.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.015
      Issue No: Vol. 87 (2017)
       
  • On the effectiveness of Monte Carlo for initial uncertainty forecasting in
           nonlinear dynamical systems
    • Authors: Chao Yang; Mrinal Kumar
      Pages: 301 - 309
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Chao Yang, Mrinal Kumar
      This paper considers the problem of initial uncertainty forecasting in deterministic nonlinear continuous-time dynamical systems via particle ensembles. The popular Monte Carlo method, which while simple to implement, faces fundamental issues. In particular, it is not clear how well the propagated particles continue to represent the true state-uncertainty at future times. This paper evaluates the performance of Monte Carlo forecasting by analyzing it in the context of Markov chain Monte Carlo (MCMC) theory. The propagated ensemble is viewed as the realization of a Markov chain at each time instant, generated by an associated instantaneous transition kernel. It is shown that for a special class of nonlinear systems that have zero divergence, the propagated kernel is in detailed balance with the true state probability density function. This guarantees statistical consistency of the Monte Carlo ensemble with the truth at all times for such systems. On the other hand, no such guarantee is possible for systems with non-zero divergence.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.09.025
      Issue No: Vol. 87 (2017)
       
  • A novel Lyapunov function for a non-weighted L2 gain of asynchronously
           switched linear systems
    • Authors: Shuai Yuan; Lixian Zhang; Bart De Schutter; Simone Baldi
      Pages: 310 - 317
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Shuai Yuan, Lixian Zhang, Bart De Schutter, Simone Baldi
      In this paper, a novel Lyapunov function is proposed to study switched linear systems with a switching delay between activation of system modes and activation of candidate controller modes. The novelty consists in continuity of the Lyapunov function at the switching instants and discontinuity when the system modes and controller modes are matched. This structure is exploited to construct a time-varying Lyapunov function that is non-increasing at time instants of discontinuity. Stability criteria based on the novel Lyapunov function are developed to guarantee global asymptotic stability in the noiseless case. Most importantly, when exogenous disturbances are considered, the proposed Lyapunov function can be used to guarantee a finite non-weighted L 2 gain for asynchronously switched systems, for which Lyapunov functions proposed in literature are inconclusive. A numerical example illustrates the effectiveness of the proposed method.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.018
      Issue No: Vol. 87 (2017)
       
  • The quest for the right kernel in Bayesian impulse response
           identification: The use of OBFs
    • Authors: Mohamed Abdelmonim Hassan Darwish; Gianluigi Pillonetto; Roland Tóth
      Pages: 318 - 329
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Mohamed Abdelmonim Hassan Darwish, Gianluigi Pillonetto, Roland Tóth
      Kernel-based regularization approaches for impulse response estimation of Linear Time-Invariant (LTI) systems have received a lot of attention recently. The reason is that regularized least-squares estimators may achieve a favorable bias/variance trade-off compared with classical Prediction Error Minimization (PEM) methods. To fully exploit this property, the kernel function needs to capture relevant aspects of the data-generating system at hand. Hence, it is important to design automatic procedures for kernel design based on data or prior knowledge. The kernel models, so far introduced, focus on encoding smoothness and BIBO-stability of the expected impulse response while other properties, like oscillatory behavior or the presence of fast and slow poles, have not been successfully implemented in kernel design. Inspired by the representation theory of dynamical systems, we show how to build stable kernels that are able to capture particular aspects of system dynamics via the use of Orthonormal Basis Functions (OBFs). In particular, desired dynamic properties can be easily encoded via the generating poles of OBFs. Such poles are seen as hyperparameters which are tuned via marginal likelihood optimization. Special cases of our kernel construction include Laguerre, Kautz, and Generalized OBFs (GOBFs)-based kernel structures. Monte-Carlo simulations show that the OBFs-based kernels perform well compared with stable spline/TC kernels, especially for slow systems with dominant poles close to the unit circle. Moreover, the capability of Kautz basis to model resonating systems is also shown.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.007
      Issue No: Vol. 87 (2017)
       
  • Dissipative approach to sliding mode observers design for uncertain
           mechanical systems
    • Authors: W. Alejandro Apaza-Perez; Jaime A. Moreno; Leonid M. Fridman
      Pages: 330 - 336
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): W. Alejandro Apaza-Perez, Jaime A. Moreno, Leonid M. Fridman
      A class of nonlinear uncertain mechanical systems with the Coriolis term, is considered. Since these systems generally do not satisfy the bounded-input-bounded-state property, a global sliding-mode observer with theoretically exact finite-time convergence using dissipative properties, is proposed.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.016
      Issue No: Vol. 87 (2017)
       
  • Co-design of output feedback laws and event-triggering conditions for the
           L2-stabilization of linear systems
    • Authors: Mahmoud Abdelrahim; Romain Postoyan; Jamal Daafouz; Dragan Nešić; Maurice Heemels
      Pages: 337 - 344
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Mahmoud Abdelrahim, Romain Postoyan, Jamal Daafouz, Dragan Nešić, Maurice Heemels
      We investigate the L 2 -stabilization of linear systems using output feedback event-triggered controllers. In particular, we are interested in the scenario where the plant output and the control input are transmitted to the controller and to the actuators, respectively, over two different digital channels, which have their own sampling rule. The plant dynamics is affected by external disturbances and the output measurement and the control input are corrupted by noises. We present a co-design procedure to simultaneously synthesize dynamic output feedback laws and event-triggering conditions such that the closed-loop system is L 2 -stable with a given upper-bound on the L 2 -gain. The required conditions are formulated in terms of the feasibility of linear matrix inequalities (LMIs). Then, we exploit these LMIs to maximize the guaranteed minimum time between two transmissions of the plant output and/or of the control input. We also present a heuristic method to reduce the amount of transmissions for each channel. The developed technique encompasses time-driven (and so periodic) sampling as a particular case and the result is also new in this context. The effectiveness of the proposed methods is illustrated on a numerical example.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.008
      Issue No: Vol. 87 (2017)
       
  • Deadlock characterization and control of flexible assembly systems with
           Petri nets
    • Authors: Keyi Xing; Feng Wang; Meng Chu Zhou; Hang Lei; Jianchao Luo
      Pages: 358 - 364
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Keyi Xing, Feng Wang, Meng Chu Zhou, Hang Lei, Jianchao Luo
      Efficient deadlock controllers are critical in the operation of automated manufacturing systems. This work focuses on a deadlock control problem for flexible assembly systems (FAS). Petri nets are used to model the systems. Through their liveness analysis, it characterizes two kinds of structural objects. Each object can lead to a siphon, and may cause the system to deadlock. Based on such objects, a necessary and sufficient condition about the liveness of Petri net models is obtained. In order to prevent each such object from causing FAS to deadlock, a Petri net controller is designed such that its induced siphon cannot be empty. The conjunction of all these controllers is proved to be capable of ensuring deadlock-free operation of a large class of FAS. The effectiveness of the proposed approach is shown via an FAS example.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.09.001
      Issue No: Vol. 87 (2017)
       
  • Adaptive compensation for infinite number of actuator failures based on
           tuning function approach
    • Authors: Guanyu Lai; Changyun Wen; Zhi Liu; Yun Zhang; C.L. Philip Chen; Shengli Xie
      Pages: 365 - 374
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Guanyu Lai, Changyun Wen, Zhi Liu, Yun Zhang, C.L. Philip Chen, Shengli Xie
      In controlling nonlinear uncertain systems, compensating for infinite number of actuator failures/faults based on the well-known tuning function approach is an important, yet challenging problem in the field of adaptive control. In fact, it has been illustrated through simulation examples that instability is observed when an existing tuning function based scheme designed for compensating finite number of actuator failures is applied to an infinite number case. So far, there is still no solution to this problem. In this paper, we address this issue by proposing a novel adaptive scheme. Technically, our scheme is developed from a new piecewise Lyapunov function analysis, the parameter projection and a modified tuning function method. It is proved that all closed-loop signals are ensured bounded by the control scheme even there is a possibility that the actuator failures take place infinitely, provided that the minimum time interval between two successive failures is bounded below by any positive scalar. Moreover, the ultimate bound of tracking error can be reduced arbitrarily small even for relatively frequent failures. In addition, a guideline for improving transient performance in terms of L 2 -norm of tracking error is also established. Perfect asymptotic tracking is obtained when the total number of actuator failures becomes finite.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.07.014
      Issue No: Vol. 87 (2017)
       
  • Intrinsic tetrahedron formation of reduced attitude
    • Authors: Silun Zhang; Wenjun Song; Fenghua He; Yiguang Hong; Xiaoming Hu
      Pages: 375 - 382
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Silun Zhang, Wenjun Song, Fenghua He, Yiguang Hong, Xiaoming Hu
      In this paper, formation control for reduced attitude is studied, in which a regular tetrahedron formation can be achieved and shown to be asymptotically stable under a large family of gain functions in the control. Moreover, by further restriction on the control gain, almost global stability of the desired formation is obtained. In addition, the control proposed is an intrinsic protocol that only uses relative information and does not need to contain any information of the desired formation beforehand. The constructed formation pattern is totally attributed to the geometric properties of the space and the designed inter-agent connection topology. Besides, a novel coordinates transformation is proposed to represent the relative reduced attitudes in S 2 , which is shown to be an efficient approach to reduced attitude formation problems.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.023
      Issue No: Vol. 87 (2017)
       
  • An efficient LQR design for discrete-time linear periodic system based on
           a novel lifting method
    • Authors: Yaguang Yang
      Pages: 383 - 388
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Yaguang Yang
      This paper proposes a novel lifting method which converts the standard discrete-time linear periodic system to an augmented linear time-invariant system. The linear quadratic optimal control is then based on the solution of the discrete-time algebraic Riccati equation associated with the augmented linear time-invariant model. An efficient algorithm for solving the Riccati equation is derived by using the special structure of the augmented linear time-invariant system. It is shown that the proposed method is very efficient, compared to the ones that use algorithms for discrete-time periodic algebraic Riccati equation. The efficiency and effectiveness of the proposed algorithm is demonstrated by the simulation test for the design problem of spacecraft attitude control using magnetic torques.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.10.019
      Issue No: Vol. 87 (2017)
       
  • Delays-dependent region partitioning approach for stability criterion of
           linear systems with multiple time-varying delays
    • Authors: Kab Seok Ko; Won Il Lee; PooGyeon Park; Dan Keun Sung
      Pages: 389 - 394
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Kab Seok Ko, Won Il Lee, PooGyeon Park, Dan Keun Sung
      This paper considers a delay-dependent stability criterion for linear systems with multiple time-varying delays. To exploit all possible information for the relationships among the marginally delayed states ( x ( t − τ i M ) , x ( t − τ i + 1 M ) ), the exactly delayed states ( x ( t − τ i ( t ) ) , x ( t − τ i + 1 ( t ) ) ), and the current state x ( t ) for each pair ( i , i + 1 ) of time-varying delays, a delays-dependent region partitioning approach in double integral terms is proposed. By applying the Wirtinger-based integral inequality and the reciprocally convex approach to terms resulted from the region partitioning, a stability criterion is derived in terms of linear matrix inequalities. Numerical examples show that the resulting criterion outperforms the existing one in literature.

      PubDate: 2017-11-09T02:38:54Z
      DOI: 10.1016/j.automatica.2017.09.003
      Issue No: Vol. 87 (2017)
       
  • An iterative algorithm for discrete periodic Lyapunov matrix equations
    • Authors: Ai-Guo Wu; Wen-Xue Zhang; Ying Zhang
      Pages: 395 - 403
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Ai-Guo Wu, Wen-Xue Zhang, Ying Zhang
      In this paper, a novel iterative algorithm with a tuning parameter is developed to solve the forward discrete periodic Lyapunov matrix equation associated with discrete-time linear periodic systems. An important feature of the proposed algorithm is that the information in the current and the last steps is used to update the iterative sequence. The convergence rate of the algorithm can be significantly improved by choosing a proper tuning parameter. It is shown that the sequence generated by this algorithm with zero initial conditions monotonically converges to the unique positive definite solution of the periodic Lyapunov matrix equation if the tuning parameter is within the interval ( 0 , 1 ] . In addition, a necessary and sufficient convergence condition is given for the proposed algorithm in terms of the roots of a set of polynomial equations. Also, a method to choose the optimal parameter is developed such that the algorithm has the fastest convergence rate. Finally, numerical examples are provided to illustrate the effectiveness of the proposed algorithm.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.06.012
      Issue No: Vol. 87 (2017)
       
  • Stochastic feedback coupling synchronization of networked harmonic
           oscillators
    • Authors: Jingyi Wang; Chen Xu; Michael Z.Q. Chen; Jianwen Feng; Guanrong Chen
      Pages: 404 - 411
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Jingyi Wang, Chen Xu, Michael Z.Q. Chen, Jianwen Feng, Guanrong Chen
      This paper presents a stochastic feedback coupling strategy for almost sure exponential synchronization of networked harmonic oscillators. Differing from most of existing publications, in which noise is not beneficial to synchronization in complex dynamical networks, a stochastic coupling strategy is designed here by using discrete-time noisy sampled-data to achieve the almost sure exponential synchronization of networked harmonic oscillators. Both leaderless synchronization and leader-following synchronization of networked harmonic oscillators are considered. Some sufficient conditions are established to reach two types of synchronization by employing algebraic graph theory, Itô stochastic integral, stochastic control technique and mathematical analysis. Two numerical simulations are provided to illustrate the effectiveness of the theoretical results.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.10.011
      Issue No: Vol. 87 (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)
       
  • 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)
       
  • Rendezvous with connectivity preservation of mobile agents subject to
           uniform time-delays
    • Authors: Maobin
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Maobin Lu
      This paper investigates the problem of rendezvous with connectivity preservation for a group of mobile agents subject to both unknown input delay and unknown communication delay. We propose a new potential function and design a potential function based distributed control law. To tackle unknown time-delays, we introduce a control gain in the control law and develop an energy functional to characterize the energy of the whole system. By analyzing the energy change, the control gain is designed. It is shown that as long as the communication network is connected at the initial time, the proposed control law can make all agents reach the same location and maintain connectivity of the communication network for all time. Meanwhile, it can accommodate arbitrarily bounded uniform constant input delay and communication delay.

      PubDate: 2017-12-12T21:06:53Z
       
  • A probabilistic framework for the control of systems with discrete states
           and stochastic excitation
    • Authors: Gianluca Meneghello; Paolo Luchini; Thomas Bewley
      Abstract: Publication date: Available online 6 December 2017
      Source:Automatica
      Author(s): Gianluca Meneghello, Paolo Luchini, Thomas Bewley
      A probabilistic framework is proposed for the optimization of efficient switched control strategies for physical systems dominated by stochastic excitation. In this framework, the equation for the state trajectory is replaced with an equivalent equation for its probability distribution function in the constrained optimization setting. This allows for a large class of control rules to be considered, including hysteresis and a mix of continuous and discrete random variables. The problem of steering atmospheric balloons within a stratified flowfield is a motivating application; the same approach can be extended to a variety of mixed-variable stochastic systems and to new classes of control rules.

      PubDate: 2017-12-12T21:06:53Z
      DOI: 10.1016/j.automatica.2017.11.001
       
  • Constrained control of input–output linearizable systems using control
           sharing barrier functions
    • Authors: Xiangru
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Xiangru Xu
      Control barrier functions (CBFs) have been used as an effective tool for designing a family of controls that ensures the forward invariance of a set. When multiple CBFs are present, it is important that the set of controls satisfying all the barrier conditions is non-empty. In this paper, we investigate such a control-sharing property for multiple CBFs and provide sufficient and necessary conditions for the property to hold. Based on that, we study the tracking control design problem of an input–output linearizable system with multiple time-varying output constraints, where the output constraints are encoded as CBFs and the barrier conditions are expressed as hard constraints in a quadratic program (QP) whose feasibility is guaranteed by the control-sharing property of the CBFs. With the controller generated from the QP, the output constraints are always satisfied and the tracking objective is achieved when it is not conflicting with the constraints. The effectiveness of our control design method is illustrated by two examples.

      PubDate: 2017-10-25T19:02:33Z
       
  • Conservation and decay laws in distributed coordination control systems
    • Authors: Zhiyong Sun; Shaoshuai Mou Brian D.O. Anderson Changbin
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Zhiyong Sun, Shaoshuai Mou, Brian D.O. Anderson, Changbin Yu
      In this paper we discuss and discover several conservation and associated decay laws in distributed coordination control systems, in particular in formation shape control systems. Specifically, we reveal conservations of linear momentum and angular momentum for gradient-based multi-agent formation systems modelled by single integrators, and show several corresponding conservation/decay laws for double-integrator formation stabilization systems and double-integrator flocking systems, respectively. By exploiting translation and rotation symmetry properties and insights from Noether’s theorem, we further establish a multi-agent version of the relation between symmetry and conservation laws for gradient-based coordination systems derived from general potential functions, from which we generalize the conservation/decay laws to more general networked coordination control systems. The results hold in ambient spaces of any dimensions, and we focus on the 2-D and 3-D cases due to their natural interpretation as positions of agents.

      PubDate: 2017-10-11T06:24:11Z
       
 
 
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