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  Subjects -> COMPUTER SCIENCE (Total: 1977 journals)
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COMPUTER SCIENCE (1150 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: 11)
Abakós     Open Access   (Followers: 3)
Academy of Information and Management Sciences Journal     Full-text available via subscription   (Followers: 67)
ACM Computing Surveys     Hybrid Journal   (Followers: 23)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 4)
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: 12)
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: 9)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 4)
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: 10)
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: 25)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 15)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
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: 3)
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 Factors/Ergonomics     Full-text available via subscription   (Followers: 24)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
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  
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: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 6)
American Journal of Sensor Technology     Open Access   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 5)
Analysis in Theory and Applications     Hybrid Journal  
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
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: 1)
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: 31)
Applied Medical Informatics     Open Access   (Followers: 9)
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: 4)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 121)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 5)
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: 8)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Basin Research     Hybrid Journal   (Followers: 3)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Bioinformatics     Hybrid Journal   (Followers: 235)
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: 32)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 122)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 13)
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)
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: 14)
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: 19)
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: 51)
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: 1)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 8)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 13)
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: 28)
Computer     Full-text available via subscription   (Followers: 81)
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: 13)
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: 10)
Computer Science Education     Hybrid Journal   (Followers: 12)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Master Research     Open Access   (Followers: 10)

        1 2 3 4 5 6 | Last

Journal Cover Automatica
  [SJR: 4.315]   [H-I: 188]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0005-1098
   Published by Elsevier Homepage  [3034 journals]
  • Asymptotic stability in probability for Stochastic Boolean Networks
    • Authors: Corrado Possieri; Andrew R. Teel
      Pages: 1 - 9
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Corrado Possieri, Andrew R. Teel
      In this paper, a new class of Boolean networks, called Stochastic Boolean Networks, is presented. These systems combine some features of the classical deterministic Boolean networks (the state variables admit two operation levels, either 0 or 1) and of Probabilistic Boolean Networks (at each time instant the transition map is selected through a random process), enriching the set of admissible dynamical behaviors, thanks to the set-valued nature of the transition map. Necessary and sufficient Lyapunov conditions are given to guarantee global asymptotic stability (resp., global asymptotic stability in probability) of a given set for a deterministic Boolean network with set–valued transition map (resp., for a Stochastic Boolean Network). A constructive procedure to compute a Lyapunov function (resp., stochastic Lyapunov function) relative to a given set for a deterministic Boolean network with set–valued transition map (resp., Stochastic Boolean Network) is reported.

      PubDate: 2017-05-28T07:15:20Z
      DOI: 10.1016/j.automatica.2017.04.040
      Issue No: Vol. 83 (2017)
       
  • Symbolic control design for monotone systems with directed specifications
    • Authors: Eric S. Kim; Murat Arcak; Sanjit A. Seshia
      Pages: 10 - 19
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Eric S. Kim, Murat Arcak, Sanjit A. Seshia
      We study the control of monotone systems when the objective is to maintain trajectories in a directed set (that is, either upper or lower set) within a signal space. We define the notion of a directed alternating simulation relation and show how it can be used to tackle common bottlenecks in abstraction-based controller synthesis. First, we develop sparse abstractions to speed up the controller synthesis procedure by reducing the number of transitions. Next, we enable a compositional synthesis approach by employing directed assume–guarantee contracts between systems. In a vehicle traffic network example, we synthesize an intersection signal controller while dramatically reducing runtime and memory requirements compared to previous approaches.

      PubDate: 2017-06-02T05:20:13Z
      DOI: 10.1016/j.automatica.2017.04.060
      Issue No: Vol. 83 (2017)
       
  • On optimization of stochastic max–min-plus-scaling systems—An
           approximation approach
    • Authors: Samira S. Farahani; Ton van den Boom; Bart De Schutter
      Pages: 20 - 27
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Samira S. Farahani, Ton van den Boom, Bart De Schutter
      A large class of discrete-event and hybrid systems can be described by a max–min-plus-scaling (MMPS) model, i.e., a model in which the main operations are maximization, minimization, addition, and scalar multiplication. Accordingly, optimization of MMPS systems appears in different problems defined for discrete-event and hybrid systems. For a stochastic MMPS system, this optimization problem is computationally highly demanding as often numerical integration has to be used to compute the objective function. The aim of this paper is to decrease such computational complexity by applying an approximation method that is based on the moments of a random variable and that can be computed analytically.

      PubDate: 2017-06-07T07:31:30Z
      DOI: 10.1016/j.automatica.2017.05.001
      Issue No: Vol. 83 (2017)
       
  • Impulsive stabilization of a class of singular systems with time-delays
    • Authors: Wu-Hua Chen; Wei Xing Zheng; Xiaomei Lu
      Pages: 28 - 36
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Wu-Hua Chen, Wei Xing Zheng, Xiaomei Lu
      This paper deals with the impulsive stabilization problem for a class of linear singular systems with time-delays. The stabilization is achieved by only exerting impulsive action on the slow state variables. Two novel Lyapunov methods are presented to determine exponential stability of the impulsively controlled systems. For the case where the time-delay is unknown and may be time-varying, a Lyapunov–Razumikhin method is developed, in which the Razumikhin condition is constructed by exploiting the relation among the fast state variables, the slow state variables, and their initial values. For the case where the delay derivative is strictly less than 1, a descriptor type of impulse-time-dependent Lyapunov functional is introduced, which is discontinuous at impulse times but does not grow along the state trajectories by construction. By using a convex technique, the stability criteria are expressed in terms of linear matrix inequalities (LMIs). Then, the impulsive controllers can be designed in the framework of LMIs. The effectiveness and advantages of the proposed methods are confirmed through simulation results.

      PubDate: 2017-06-12T07:36:52Z
      DOI: 10.1016/j.automatica.2017.05.008
      Issue No: Vol. 83 (2017)
       
  • Exponential convergence of a distributed algorithm for solving linear
           algebraic equations
    • Authors: Ji Liu; A. Stephen Morse; Angelia Nedić; Tamer Başar
      Pages: 37 - 46
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Ji Liu, A. Stephen Morse, Angelia Nedić, Tamer Başar
      In a recent paper, a distributed algorithm was proposed for solving linear algebraic equations of the form A x = b assuming that the equation has at least one solution. The equation is presumed to be solved by m agents assuming that each agent knows a subset of the rows of the matrix A b , the current estimates of the equation’s solution generated by each of its neighbors, and nothing more. Neighbor relationships are represented by a time-dependent directed graph N ( t ) whose vertices correspond to agents and whose arcs characterize neighbor relationships. Sufficient conditions on N ( t ) were derived under which the algorithm can cause all agents’ estimates to converge exponentially fast to the same solution to A x = b . These conditions were also shown to be necessary for exponential convergence, provided the data about A b available to the agents is “non-redundant”. The aim of this paper is to relax this “non-redundant” assumption. This is accomplished by establishing exponential convergence under conditions which are the weakest possible for the problem at hand; the conditions are based on a new notion of graph connectivity. An improved bound on the convergence rate is also derived.

      PubDate: 2017-06-07T07:31:30Z
      DOI: 10.1016/j.automatica.2017.05.004
      Issue No: Vol. 83 (2017)
       
  • Filtering S-coupled algebraic Riccati equations for discrete-time Markov
           jump systems
    • Authors: Oswaldo Luiz do Valle Costa; Danilo Zucolli Figueiredo
      Pages: 47 - 57
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Oswaldo Luiz do Valle Costa, Danilo Zucolli Figueiredo
      This paper deals with a set of S -coupled algebraic Riccati equations that arises in the study of filtering of discrete-time linear jump systems with the Markov chain in a general Borel space S . By S -coupled it is meant that the algebraic Riccati equations are coupled via an integral over S . Conditions for the existence and uniqueness of a positive semi-definite solution to the filtering S -coupled algebraic Riccati equations are obtained in terms of the concepts of stochastic detectability and stochastic stabilizability. This result is then applied to solve the infinite horizon minimum mean square linear Markov jump filtering problem. The obtained results generalize previous ones in the literature, which considered only the case of the Markov chain taking values in a finite state space.

      PubDate: 2017-06-07T07:31:30Z
      DOI: 10.1016/j.automatica.2017.05.007
      Issue No: Vol. 83 (2017)
       
  • Properties and stability analysis of discrete-time negative imaginary
           systems
    • Authors: Mei Liu; Junlin Xiong
      Pages: 58 - 64
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Mei Liu, Junlin Xiong
      This paper is concerned with discrete-time negative imaginary (DT-NI) functions. First, a new definition of DT-NI functions is introduced. Then, by means of the relations between discrete-time positive real and DT-NI functions, two different versions of DT-NI lemmas are established to characterize the DT-NI properties based on state-space realizations. Also, a necessary and sufficient condition is presented to guarantee the internal stability of positive feedback interconnected DT-NI systems. Meanwhile, some other properties of DT-NI functions are studied. Several numerical examples are presented to illustrate the main results of this paper. Compared to the previous results, our results remove the symmetric assumption in rational case.

      PubDate: 2017-06-07T07:31:30Z
      DOI: 10.1016/j.automatica.2017.05.006
      Issue No: Vol. 83 (2017)
       
  • Maximum delay bounds of linear systems under delay independent truncated
           predictor feedback
    • Authors: Yusheng Wei; Zongli Lin
      Pages: 65 - 72
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Yusheng Wei, Zongli Lin
      In a predictor feedback law for a linear system with input delay, the future state is predicted as the state solution of the linear system. The zero input solution contains the transition matrix. The zero state solution gives rise to the distributed nature of the feedback law. In a 2007 IEEE TAC paper, it is established that, when the system is not exponentially unstable, low gain feedback can be designed such that the predictor feedback law, with the distributed term truncated, still achieves stabilization for an arbitrarily large delay. Furthermore, in the absence of purely imaginary poles, the transition matrix in the truncated predictor feedback (TPF) can be safely dropped, resulting in a delay independent TPF law, which is simply a delay independent linear state feedback. In this paper, we first construct an example to show that, in the presence of purely imaginary poles, the linear delay independent TPF in general cannot stabilize the system for an arbitrarily large delay. By using the Lyapunov–Krasovskii Stability Theorem, we derive a bound on the delay under which the delay independent truncated predictor feedback law achieves stabilization for a general system that may be exponentially unstable.

      PubDate: 2017-06-12T07:36:52Z
      DOI: 10.1016/j.automatica.2017.05.003
      Issue No: Vol. 83 (2017)
       
  • Supervised control of buck-boost converters for aeronautical applications
    • Authors: Alberto Cavallo; Giacomo Canciello; Beniamino Guida
      Pages: 73 - 80
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Alberto Cavallo, Giacomo Canciello, Beniamino Guida
      Recent MEA (More Electric Aircraft) concepts require new approaches to design and management of the electric system onboard. Bidirectional Buck-Boost Converter Units (BBCU’s) used like bridges between power buses with different voltage require intelligent supervisory control for autonomous selection of operating modes. In this paper at low-level, sliding manifold-based strategies are employed to track desired current references, or to recover from overload within a prescribed time. At a higher level, three working modes are defined, (Buck-, Boost- and Intermediate-Mode), and scheduled by a high-level supervisory strategy. Stability proofs of the overall strategy require estimates of the Region of Attraction (ROA) for each controller, that are discussed in the paper. A typical aeronautic scenario is presented, with standard operating conditions followed by two types of overloads (the second more severe than the first) and finally a return to standard condition. Detailed numerical simulations show the effectiveness of the proposed novel control strategy in terms of stability and performance of the smart converter.

      PubDate: 2017-06-16T07:37:50Z
      DOI: 10.1016/j.automatica.2017.05.005
      Issue No: Vol. 83 (2017)
       
  • A framework for multivariable algebraic loops in linear anti-windup
           implementations
    • Authors: Ambrose Adebayo Adegbege; William Paul Heath
      Pages: 81 - 90
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Ambrose Adebayo Adegbege, William Paul Heath
      This brief paper addresses the implementation and well-posedness aspects of multivariable algebraic loops which arise naturally in many anti-windup control schemes. Using the machinery of linear complementarity problems, a unified framework is developed for establishing well-posedness of such algebraic loops. Enforcing well-posedness is reduced to a linear matrix inequality feasibility problem that can be solved during the anti-windup design stage. Several existing anti-windup implementations appear as special cases of the unified framework presented in this brief paper.

      PubDate: 2017-06-16T07:37:50Z
      DOI: 10.1016/j.automatica.2017.05.009
      Issue No: Vol. 83 (2017)
       
  • Extremum seeking for dynamic maps using Lie brackets and singular
           perturbations
    • Authors: Hans-Bernd Dürr; Miroslav Krstić; Alexander Scheinker; Christian Ebenbauer
      Pages: 91 - 99
      Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Hans-Bernd Dürr, Miroslav Krstić, Alexander Scheinker, Christian Ebenbauer
      We introduce a framework for the analysis of extremum seeking systems for dynamic maps based on Lie bracket approximations and singular perturbation theory. Using the introduced framework, we provide an extremum seeking regulator for a unicycle and prove its stability properties.

      PubDate: 2017-06-16T07:37:50Z
      DOI: 10.1016/j.automatica.2017.05.002
      Issue No: Vol. 83 (2017)
       
  • On adaptive covariance and spectrum estimation of locally stationary
           multivariate processes
    • Authors: Maciej Niedźwiecki; Marcin Ciołek; Yoshinobu Kajikawa
      Pages: 1 - 12
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Maciej Niedźwiecki, Marcin Ciołek, Yoshinobu Kajikawa
      When estimating the correlation/spectral structure of a locally stationary process, one has to make two important decisions. First, one should choose the so-called estimation bandwidth, inversely proportional to the effective width of the local analysis window, in the way that complies with the degree of signal nonstationarity. Too small bandwidth may result in an excessive estimation bias, while too large bandwidth may cause excessive estimation variance. Second, but equally important, one should choose the appropriate order of the spectral representation of the signal so as to correctly model its resonant structure–when the order is too small, the estimated spectrum may not reveal some important signal components (resonances), and when it is too high, it may indicate the presence of some nonexistent components. When the analyzed signal is not stationary, with a possibly time-varying degree of nonstationarity, both the bandwidth and order parameters should be adjusted in an adaptive fashion. The paper presents and compares three approaches allowing for unified treatment of the problem of adaptive bandwidth and order selection for the purpose of identification of nonstationary vector autoregressive processes: the cross-validation approach, the full cross-validation approach, and the approach that incorporates the multivariate version of the generalized Akaike’s final prediction error criterion. It is shown that the latter solution yields the best results and, at the same time, is very attractive from the computational viewpoint.

      PubDate: 2017-05-03T02:51:31Z
      DOI: 10.1016/j.automatica.2017.04.033
      Issue No: Vol. 82 (2017)
       
  • Disturbance scaling in bidirectional vehicle platoons with different
           asymmetry in position and velocity coupling
    • Authors: Ivo Herman; Steffi Knorn; Anders Ahlén
      Pages: 13 - 20
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Ivo Herman, Steffi Knorn, Anders Ahlén
      This paper considers a string of vehicles where the local control law uses the states of the vehicle’s immediate predecessor and follower. The coupling towards the preceding vehicle can be chosen different to the coupling with the following vehicle, which is referred to as an asymmetric bidirectional string. Further, the asymmetry for the velocity coupling can be chosen differently to the asymmetry in the position coupling. It is investigated how the effect of the disturbance on the control errors in the string depends on the string length. It is shown, that in case of symmetric position coupling and asymmetric velocity coupling, linear scaling can be achieved. For symmetric interactions, the errors scale quadratically in the number of vehicles. When the coupling in position is asymmetric, exponential scaling may occur or the system might even become unstable. The paper thus gives a comprehensive overview of the achievable performance in linear, asymmetric, bidirectional platoons. The results reveal that symmetry in the position coupling and asymmetry in velocity coupling qualitatively improve the performance of the string. Extensive numerical results illustrate the theoretical findings.

      PubDate: 2017-05-08T15:37:36Z
      DOI: 10.1016/j.automatica.2017.04.010
      Issue No: Vol. 82 (2017)
       
  • Adaptive repetitive learning control for an offshore boom crane
    • Authors: Yuzhe Qian; Yongchun Fang; Biao Lu
      Pages: 21 - 28
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Yuzhe Qian, Yongchun Fang, Biao Lu
      This paper proposes an efficient nonlinear controller for an offshore boom crane, which is a combination of a learning strategy and an adaptive robust control method. An offshore boom crane is a kind of typical underactuated system which has less number of actuators than its degrees of freedom (DOFs), and it is also a sophisticated nonlinear system with strong-coupling characteristics, therefore, controller design for this kind of system becomes an extremely challenging task. Moreover, different from an overhead crane fixed on land, an offshore boom crane fixed on a vessel suffers from some peculiar disturbances of the attached ship’s multi-dimensional movement induced by waves and ocean currents, which implies that the motion of the ship can cause a tremendous effect on this system. Considering the periodic property of sea waves, this paper proposes an adaptive repetitive learning control strategy containing a learning law to deal with the aforementioned practical problems, as well as an adaptive law to handle the unknown system parameters. Specifically, different from traditional learning control strategy, the proposed control algorithm successfully addresses unknown periods of the periodic disturbances by introducing a period identifier into the control scheme. Meanwhile, the developed control strategy presents good robustness against ever-lasting disturbances and unknown parameters. The stability of the designed closed-loop system is guaranteed in the Lyapunov sense. Furthermore, some comparative experimental results are presented to demonstrate the efficiency of the proposed control method.

      PubDate: 2017-05-08T15:37:36Z
      DOI: 10.1016/j.automatica.2017.04.003
      Issue No: Vol. 82 (2017)
       
  • Stability of decentralized model predictive control of graph-based power
           flow systems via passivity
    • Authors: Justin P. Koeln; Andrew G. Alleyne
      Pages: 29 - 34
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Justin P. Koeln, Andrew G. Alleyne
      This work presents a passivity-based stability guarantee for the decentralized control of nonlinear power flow systems. This class of systems is characterized using a graph-based modeling approach, where vertices represent capacitive elements that store energy and edges represent power flow between these capacitive elements. Due to their complexity and size, these power flow systems are often decomposed into dynamically coupled subsystems, where this coupling stems from the exchange of power between subsystems. Each subsystem has a corresponding model predictive controller that can be part of a decentralized, distributed, or larger hierarchical control structure. By exploiting the structure of the coupling between subsystems, stability of the closed-loop system is guaranteed by augmenting each model predictive controller with a local passivity constraint.

      PubDate: 2017-05-08T15:37:36Z
      DOI: 10.1016/j.automatica.2017.04.026
      Issue No: Vol. 82 (2017)
       
  • Fault prognosis of timed stochastic discrete event systems with bounded
           estimation error
    • Authors: Rabah Ammour; Edouard Leclercq; Eric Sanlaville; Dimitri Lefebvre
      Pages: 35 - 41
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Rabah Ammour, Edouard Leclercq, Eric Sanlaville, Dimitri Lefebvre
      This article deals with the problem of fault prognosis in timed stochastic discrete event systems. For that purpose, partially observed stochastic Petri nets are considered to model the system with its sensors. The model represents both healthy and faulty behaviors of the system. Using a timed measurement sequence issued from the sensors, an approach denoted ( ρ , δ ) -prognosis is proposed to estimate the probability of a future fault occurrence. The method is based on two input parameters: the error bound ρ and the prognosis horizon δ . The main contribution is to bound the estimation error by ρ when the prognosis horizon does not exceed δ . An example is presented to illustrate the results.

      PubDate: 2017-05-08T15:37:36Z
      DOI: 10.1016/j.automatica.2017.04.028
      Issue No: Vol. 82 (2017)
       
  • Observer design for networked control systems with FlexRay
    • Authors: Wei Wang; Dragan Nešić; Romain Postoyan
      Pages: 42 - 48
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Wei Wang, Dragan Nešić, Romain Postoyan
      We design state observers for nonlinear networked control systems (NCS) implemented over FlexRay. FlexRay is a communication protocol used in the automotive industry, which has the feature to switch between two scheduling rules during its communication cycles. These switches induce technical difficulties when modeling, designing and analyzing observers for such systems compared to standard NCS. We present a solution based on the emulation approach. Given an observer in the absence of communication constraints, we implement it over the network and we provide sufficient conditions on the latter, to preserve the stability property of the observer. In particular, we provide explicit bounds on the maximal allowable transmission intervals, which adapt to the lengths of the segment associated to each scheduling rule. We assume that the plant dynamics and measurements are affected by noise and we guarantee an input-to-state stability property for the corresponding estimation error system. The overall system is modeled as a hybrid system and the analysis relies on the use of a novel hybrid Lyapunov function.

      PubDate: 2017-05-08T15:37:36Z
      DOI: 10.1016/j.automatica.2017.03.038
      Issue No: Vol. 82 (2017)
       
  • Disturbance observer-based multirate control for rejecting periodic
           disturbances to the Nyquist frequency and beyond
    • Authors: Weili Yan; Chee Khiang Pang; Chunling Du
      Pages: 49 - 58
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Weili Yan, Chee Khiang Pang, Chunling Du
      Intersample behavior cannot be ignored when a sampled-data control system is subject to periodic disturbances beyond the Nyquist frequency. In this paper, a disturbance observer-based multirate control scheme is proposed to deal with such a periodic disturbance problem. First, using discrete-time Fourier series, the effect of the periodic disturbance on steady-state response of the plant output including intersample information is derived. Next, based on the steady-state output response, a sufficient condition is provided for minimization of the disturbance effect on the output. It turns out that solving the sufficient condition is a problem of quadratic optimization with several equality constraints. The proposed approach is applied on vibration control of mechanical resonant modes beyond the Nyquist frequency in a commercial hard disk drive. Perfect disturbance elimination and disturbance deduction of 72% in fast-rate discrete-time response are observed in the simulation and experiment, respectively.

      PubDate: 2017-05-08T15:37:36Z
      DOI: 10.1016/j.automatica.2017.04.027
      Issue No: Vol. 82 (2017)
       
  • Sampled-data relay control of diffusion PDEs
    • Authors: Anton Selivanov; Emilia Fridman
      Pages: 59 - 68
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Anton Selivanov, Emilia Fridman
      We consider a vector reaction–advection–diffusion equation on a hypercube. The measurements are weighted averages of the state over different subdomains. These measurements are asynchronously sampled in time. Subject to matched disturbances, the discrete control signals are applied through shape functions and zero-order holds. The feature of this work is that we consider generalized relay control: the control signals take their values in a finite set. This allows for networked control through low capacity communication channels. First, we derive linear matrix inequalities (LMIs) whose feasibility guarantees the ultimate boundedness with a limit bound proportional to the sampling period. Then we construct a switching procedure for the controller parameters that ensures semi-global practical stability: for an arbitrarily large domain of initial conditions the trajectories converge to a set whose size does not depend on the domain size. For the disturbance-free system this procedure guarantees exponential convergence to the origin. The results are demonstrated by two examples: 2D catalytic slab and a chemical reactor.

      PubDate: 2017-05-13T07:00:17Z
      DOI: 10.1016/j.automatica.2017.04.022
      Issue No: Vol. 82 (2017)
       
  • Identification of multivariable dynamic errors-in-variables system with
           arbitrary inputs
    • Authors: Erliang Zhang; Rik Pintelon
      Pages: 69 - 78
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Erliang Zhang, Rik Pintelon
      The present work deals with the identification of multivariable linear dynamic system from noisy input–output observations, where the input signal is arbitrary and the input–output noises are mutually correlated. A frequency domain identification framework is developed, in which the consistent estimator of the multivariable plant model parameters and of the input–output noise covariance matrix is defined as the solution of a set of normal equations and sufficient conditions for the uniqueness of the parameter estimate are established based on the rank property of the matrix of the normal equation. The uncertainty bound of the parameter estimates is constructed and compared with the Cramér–Rao lower bound. The proposed methodology is validated on a simulated multivariable dynamic system.

      PubDate: 2017-05-13T07:00:17Z
      DOI: 10.1016/j.automatica.2017.04.031
      Issue No: Vol. 82 (2017)
       
  • Event-triggered sliding mode control of stochastic systems via output
           feedback
    • Authors: Ligang Wu; Yabin Gao; Jianxing Liu; Hongyi Li
      Pages: 79 - 92
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Ligang Wu, Yabin Gao, Jianxing Liu, Hongyi Li
      This paper is concerned with event-triggered sliding mode control (SMC) for uncertain stochastic systems subject to limited communication capacity. We consider the stochastic perturbation, exogenous disturbance and the network-induced communication constraints in a whole framework of SMC design. The measurable output is adequately sampled for periodic computation of a designed event trigger. Network-induced delays are characterized in the transmission over a shared network communication from sensor to controller. An event-triggered zero-order-hold (ZOH) is employed to keep receiving and sending the delayed measurement for control updating, and a state observer is designed to estimate the system state and to facilitate the design of sliding surface. Then, based on the measurement and observer’s outputs, a novel SMC law is presented. The stochastic stability for the overall closed-loop system is analyzed, and the exogenous disturbance is attenuated in an H ∞ sense. Furthermore, the presented event-triggered SMC methods are successfully applied to multi-loop control case considering shared communication limitation. Simulation results are provided to verify the effectiveness of the proposed design scheme.

      PubDate: 2017-05-13T07:00:17Z
      DOI: 10.1016/j.automatica.2017.04.032
      Issue No: Vol. 82 (2017)
       
  • Adaptive observer design with heat PDE sensor
    • Authors: Tarek Ahmed-Ali; Fouad Giri; Miroslav Krstic; Laurent Burlion; Françoise Lamnabhi-Lagarrigue
      Pages: 93 - 100
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Tarek Ahmed-Ali, Fouad Giri, Miroslav Krstic, Laurent Burlion, Françoise Lamnabhi-Lagarrigue
      The problem of state and parameter estimation is addressed for systems with cascade structure including finite-dimensional dynamics followed in series with infinite-dimensional dynamics. The formers are captured through an ODE that is state- and parameter-affine. The latter, referred to as sensor dynamics, are represented by a diffusion parabolic PDE. Both equations are subject to parameter uncertainty. Furthermore, the connection point between the ODE and the PDE blocs is not accessible to measurements. The aim is to get online estimates of all inaccessible states and unknown parameters of both the ODE and the PDE subsystems. This observation problem is dealt with by combining the backstepping design method and the extended Kalman observer approach. The obtained adaptive observer is shown to be exponentially convergent under an ad-hoc persistent excitation condition.

      PubDate: 2017-05-13T07:00:17Z
      DOI: 10.1016/j.automatica.2017.04.030
      Issue No: Vol. 82 (2017)
       
  • Frequency-domain tools for stability analysis of reset control systems
    • Authors: S.J.L.M. van Loon; K.G.J. Gruntjens; M.F. Heertjes; N. van de Wouw; W.P.M.H. Heemels
      Pages: 101 - 108
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): S.J.L.M. van Loon, K.G.J. Gruntjens, M.F. Heertjes, N. van de Wouw, W.P.M.H. Heemels
      The potential of reset controllers to improve the transient performance of linear (motion) systems has been extensively demonstrated in the literature. The design and stability analysis of these reset controllers generally rely on the availability of parametric models and on the numerical solution of linear matrix inequalities. Both these aspects may hamper the application of reset control in industrial settings. To remove these hurdles and stimulate broader application of reset control techniques in practice, we present new sufficient conditions, based on measured frequency response data of the system to be controlled, to guarantee the stability of closed-loop reset control systems. The effectiveness of these conditions is demonstrated through experiments on an industrial piezo-actuated motion system.

      PubDate: 2017-05-18T01:37:08Z
      DOI: 10.1016/j.automatica.2017.04.008
      Issue No: Vol. 82 (2017)
       
  • Coherent-classical estimation for linear quantum systems
    • Authors: Shibdas Roy; Ian R. Petersen; Elanor H. Huntington
      Pages: 109 - 117
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Shibdas Roy, Ian R. Petersen, Elanor H. Huntington
      We study a coherent-classical estimation scheme for a class of linear quantum systems, where the estimator is a mixed quantum–classical system that may or may not involve coherent feedback. We show that when the quantum plant or the quantum part of the estimator (coherent controller) is an annihilation operator only system, coherent-classical estimation without coherent feedback can provide no improvement over purely-classical estimation. Otherwise, coherent-classical estimation without feedback can be better than classical-only estimation for certain homodyne detector angles, although the former is inferior to the latter for the best choice of homodyne detector angle. Moreover, we show that coherent-classical estimation with coherent feedback is no better than classical-only estimation, when both the plant and the coherent controller are annihilation operator only systems. Otherwise, coherent-classical estimation with coherent feedback can be superior to purely-classical estimation, and in this case, the former is better than the latter for the optimal choice of homodyne detector angle.

      PubDate: 2017-05-18T01:37:08Z
      DOI: 10.1016/j.automatica.2017.04.034
      Issue No: Vol. 82 (2017)
       
  • Stabilization and robustness analysis for time-varying systems with
           time-varying delays using a sequential subpredictors approach
    • Authors: Frédéric Mazenc; Michael Malisoff
      Pages: 118 - 127
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Frédéric Mazenc, Michael Malisoff
      We provide a new sequential predictors approach for the exponential stabilization of linear time-varying systems. Our method circumvents the problem of constructing and estimating distributed terms in the control laws, and allows arbitrarily large input delay bounds, pointwise time-varying input delays, and uncertainties. Instead of using distributed terms, our approach to handling longer delays is to increase the number of predictors. We obtain explicit formulas to find lower bounds for the number of required predictors. The formulas involve bounds on the delays and on the derivatives of the delays. We illustrate our method in three examples.

      PubDate: 2017-05-18T01:37:08Z
      DOI: 10.1016/j.automatica.2017.04.020
      Issue No: Vol. 82 (2017)
       
  • Rank-constrained optimization and its applications
    • Authors: Chuangchuang Sun; Ran Dai
      Pages: 128 - 136
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Chuangchuang Sun, Ran Dai
      This paper investigates an iterative approach to solve the general rank-constrained optimization problems (RCOPs) defined to optimize a convex objective function subject to a set of convex constraints and rank constraints on unknown rectangular matrices. In addition, rank minimization problems (RMPs) are introduced and equivalently transformed into RCOPs by introducing a quadratic matrix equality constraint. The rank function is discontinuous and nonconvex, thus the general RCOPs are classified as NP-hard in most of the cases. An iterative rank minimization (IRM) method, with convex formulation at each iteration, is proposed to gradually approach the constrained rank. The proposed IRM method aims at solving RCOPs with rank inequalities constrained by upper or lower bounds, as well as rank equality constraints. Proof of the convergence to a local minimizer with at least a sublinear convergence rate is provided. Four representative applications of RCOPs and RMPs, including system identification, output feedback stabilization, and structured H 2 controller design problems, are presented with comparative simulation results to verify the feasibility and improved performance of the proposed IRM method.

      PubDate: 2017-05-18T01:37:08Z
      DOI: 10.1016/j.automatica.2017.04.039
      Issue No: Vol. 82 (2017)
       
  • Position estimation from direction or range measurements
    • Authors: Tarek Hamel; Claude Samson
      Pages: 137 - 144
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Tarek Hamel, Claude Samson
      This paper revisits the problems of estimating the position of an object moving in n ( ≥ 2 )-dimensional Euclidean space using velocity measurements and either direction or range measurements of one or multiple source points. The proposed solutions exploit the Continuous Riccati Equation (CRE) to calculate observer gains yielding global uniform exponential stability of zero estimation errors, also when the measured velocity is biased by an unknown constant vector or when range measurements are corrupted by an unknown constant bias. With respect to prior contributions on these subjects they provide a coherent generalization of existing solutions with the preoccupation of pointing out general and explicit persistent excitation (p.e.) conditions whose satisfaction ensures uniform exponential stability of the observers.

      PubDate: 2017-05-18T01:37:08Z
      DOI: 10.1016/j.automatica.2017.04.045
      Issue No: Vol. 82 (2017)
       
  • Averaging for switched DAEs: Convergence, partial averaging and stability
    • Authors: Elisa Mostacciuolo; Stephan Trenn; Francesco Vasca
      Pages: 145 - 157
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Elisa Mostacciuolo, Stephan Trenn, Francesco Vasca
      Averaging is a useful technique to simplify the analysis of switched systems. In this paper we present averaging results for the class of systems described by switched differential algebraic equations (DAEs). Conditions on the consistency projectors are given which guarantee convergence towards a non-switched averaged system. A consequence of this result is the possibility to stabilize switched DAEs via fast switching. We also study partial averaging in case the consistency projectors do not satisfy the conditions for convergence; the averaged system is then still a switched system, but is simpler than the original. The practical interest of the theoretical averaging results is demonstrated through the analysis of the dynamics of a switched electrical circuit.

      PubDate: 2017-05-18T01:37:08Z
      DOI: 10.1016/j.automatica.2017.04.036
      Issue No: Vol. 82 (2017)
       
  • Feedback quadratic filtering
    • Authors: Filippo Cacace; Francesco Conte; Alfredo Germani; Giovanni Palombo
      Pages: 158 - 164
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Filippo Cacace, Francesco Conte, Alfredo Germani, Giovanni Palombo
      This paper concerns the state estimation problem for linear discrete-time non-Gaussian systems. It is known that filters based on quadratic functions of the measurements processes (Quadratic Filter) improve the estimation accuracy of the optimal linear filter. In order to enlarge the class of systems, which can be processed by a Quadratic Filter, we rewrite the system model by introducing an output injection term. The resulting filter, named the Feedback Quadratic Filter, can be applied also to non asymptotically stable systems. We prove that the performance of the Feedback Quadratic Filter depends on the gain parameter of the output term, which can be chosen so that the estimation error is always less than or equal to the Quadratic Filter.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.046
      Issue No: Vol. 82 (2017)
       
  • Delay dependent stability of highly nonlinear hybrid stochastic systems
    • Authors: Weiyin Fei; Liangjian Hu; Xuerong Mao; Mingxuan Shen
      Pages: 165 - 170
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Weiyin Fei, Liangjian Hu, Xuerong Mao, Mingxuan Shen
      There are lots of papers on the delay dependent stability criteria for differential delay equations (DDEs), stochastic differential delay equations (SDDEs) and hybrid SDDEs. A common feature of these existing criteria is that they can only be applied to delay equations where their coefficients are either linear or nonlinear but bounded by linear functions (namely, satisfy the linear growth condition). In other words, there is so far no delay-dependent stability criterion on nonlinear equations without the linear growth condition (we will refer to such equations as highly nonlinear ones). This paper is the first to establish delay dependent criteria for highly nonlinear hybrid SDDEs. It is therefore a breakthrough in the stability study of highly nonlinear hybrid SDDEs.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.050
      Issue No: Vol. 82 (2017)
       
  • Filter design based on characteristic functions for one class of
           multi-dimensional nonlinear non-Gaussian systems
    • Authors: Chenglin Wen; Xingshuo Cheng; Daxing Xu; Chuanbo Wen
      Pages: 171 - 180
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Chenglin Wen, Xingshuo Cheng, Daxing Xu, Chuanbo Wen
      A filter based on characteristic functions is developed in this paper, to fit to a class of non-Gaussian dynamical systems, which state models and measurement models are all nonlinear and multi-dimensional. The new filter overcomes limitations and expands the application of this kind of filter, which is proved to just fit to one special kind of systems with multi-dimensional linear state models and one-dimensional nonlinear measurement models. Firstly, the filter using characteristic function is introduced and its limitation is analysed. Then, we design the new filter to fit to nonlinear states and multi-dimensional measurements. Thirdly, the matrix format of performance index is presented to match to the new filter gain, and the weighting function vector is given to ensure the uniform boundedness of such a performance index. Finally, the new filter gain can be obtained by minimizing this performance index, and the process of filtering design is accomplished. Simulation examples are given to illustrate the effectiveness of the proposed filter design scheme.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.03.041
      Issue No: Vol. 82 (2017)
       
  • Control co-design for discrete-time switched linear systems
    • Authors: Mirko Fiacchini; Sophie Tarbouriech
      Pages: 181 - 186
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Mirko Fiacchini, Sophie Tarbouriech
      The paper deals with the co-design of a control policy, composed by both the state feedback and the switching control law, for discrete-time switched linear systems. Constructive conditions are given that are necessary and sufficient for the stabilizability of systems which are periodic stabilizable. The conditions are in form of a Linear Matrix Inequality (LMI) problem whose solution provides the switching law and a family of state feedback gains stabilizing the system as well as a bound on the exponential decreasing rate. The effectiveness of the proposed technique is illustrated by comparison with results from the literature.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.043
      Issue No: Vol. 82 (2017)
       
  • Stability of uncertain systems using Lyapunov functions with non-monotonic
           terms
    • Authors: Márcio J. Lacerda; Peter Seiler
      Pages: 187 - 193
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Márcio J. Lacerda, Peter Seiler
      This paper is concerned with the problem of robust stability of uncertain linear time-invariant systems in polytopic domains. The main contribution is to present a systematic procedure to check the stability of the uncertain systems by using an arbitrary number of quadratic functions within higher order derivatives of the vector field in the continuous-time case and higher order differences of the vector field in the discrete-time case. The matrices of the Lyapunov function appear decoupled from the dynamic matrix of the system in the conditions. This fact leads to sufficient conditions that are given in terms of Linear Matrix Inequalities defined at the vertices of the polytope. The proposed method does not impose sign condition constraints in the quadratic functions that compose the Lyapunov function individually. Moreover, some of the quadratic functions do not decrease monotonically along trajectories. However, if the sufficient conditions are satisfied, then a monotonic standard Lyapunov function that depends on the dynamics of the uncertain system can be constructed a posteriori. Numerical examples from the literature are provided to illustrate the proposed approach.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.042
      Issue No: Vol. 82 (2017)
       
  • Robust performance synthesis for systems with positive-real uncertainty
           and an extension to the negative-imaginary case
    • Authors: Kang-Zhi Liu; Masao Ono; Xiaoli Li; Min Wu
      Pages: 194 - 201
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Kang-Zhi Liu, Masao Ono, Xiaoli Li, Min Wu
      This paper addresses the robust performance synthesis problem for systems with positive-real or negative-imaginary uncertainty. The conventional robust performance design methods are mostly based on the gain information of uncertainty, which is not suitable for uncertainties characterized by the phase information. The approach taken here is based on the input–output relation of systems in the frequency-domain, which enables a less conservative yet numerically tractable solution to the robust performance synthesis. The effectiveness is validated through a detailed case study on the head positioning control of hard disk drives. The results and comparison demonstrate that the proposed method can achieve a much higher robust performance than existing methods.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.037
      Issue No: Vol. 82 (2017)
       
  • Bounds for the remainders of uncertain matrix exponential and sampled-data
           control of polytopic linear systems
    • Authors: Marc Jungers; Grace S. Deaecto; José C. Geromel
      Pages: 202 - 208
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Marc Jungers, Grace S. Deaecto, José C. Geromel
      This paper determines an explicit upper bound to the norm of any given degree of the Taylor’s expansion remainder for the matrix exponential function. It depends on the spectral norm and the corresponding measure of a square matrix. The generalization to cope with uncertain polytopic matrices follows from the definition of a norm and a measure for this mathematical entity and the determination of the corresponding upper bound for the expansion remainder. Naturally, the results are applied to robust stability analysis and state feedback control synthesis of sampled-data polytopic systems. It is shown that a sampled-data uncertain system obtained from a continuous-time polytopic one can be expressed (through a nonconservative sufficient condition) by a feedback interconnection of a discrete-time polytopic system and a norm bounded linear operator. Academical examples illustrate the theoretical results.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.057
      Issue No: Vol. 82 (2017)
       
  • High-order sliding mode observer for fractional commensurate linear
           systems with unknown input
    • Authors: Zehor Belkhatir; Taous Meriem Laleg-Kirati
      Pages: 209 - 217
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Zehor Belkhatir, Taous Meriem Laleg-Kirati
      In this paper, a high-order sliding mode observer (HOSMO) is proposed for the joint estimation of the pseudo-state and the unknown input of fractional commensurate linear systems with single unknown input and a single output. The convergence of the proposed observer is proved using a Lyapunov-based approach. In addition, an enhanced variant of the proposed fractional-HOSMO is introduced to avoid the peaking phenomenon and thus to improve the estimation results in the transient phase. Simulation results are provided to illustrate the performance of the proposed fractional observer in both noise-free and noisy cases. The effect of the observer’s gains on the estimated pseudo-state and unknown input is also discussed.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.035
      Issue No: Vol. 82 (2017)
       
  • Cooperative control of multiple stochastic high-order nonlinear systems
    • Authors: Wuquan Li; Lu Liu; Gang Feng
      Pages: 218 - 225
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Wuquan Li, Lu Liu, Gang Feng
      Distributed cooperative control of multiple stochastic high-order nonlinear systems has not been addressed in literature. This paper presents an approach to design of distributed cooperative controllers for multiple stochastic high-order nonlinear systems under directed leader–followers type network topology via the so-called distributed integrator backstepping method. By using the algebraic graph theory and stochastic analysis method, it is shown that the output tracking errors between the followers and the leader can be tuned arbitrarily small while all the states of the closed-loop system remain bounded in probability. Finally, the effectiveness of the proposed control approach is illustrated on a stochastic underactuated mechanical system.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.052
      Issue No: Vol. 82 (2017)
       
  • Extended information filter on matrix Lie groups
    • Authors: Josip Ćesić; Ivan Marković; Mario Bukal; Ivan Petrović
      Pages: 226 - 234
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Josip Ćesić, Ivan Marković, Mario Bukal, Ivan Petrović
      In this paper we propose a new state estimation algorithm called the extended information filter on Lie groups. The proposed filter is inspired by the extended Kalman filter on Lie groups and exhibits the advantages of the information filter with regard to multisensor update and decentralization, while keeping the accuracy of stochastic inference on Lie groups. We present the theoretical development and demonstrate its performance on multisensor rigid body attitude tracking by forming the state space on the SO ( 3 ) × R 3 group, where the first and second component represent the orientation and angular rates, respectively. The performance of the filter is compared with respect to the accuracy of attitude tracking with parametrization based on Euler angles and with respect to execution time of the extended Kalman filter formulation on Lie groups. The results show that the filter achieves higher performance consistency and smaller error by tracking the state directly on the Lie group and that it keeps smaller computational complexity of the information form with respect to high number of measurements.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.056
      Issue No: Vol. 82 (2017)
       
  • Constraint admissible state sets for switched systems with average dwell
           time
    • Authors: Yu Ren; Meng Joo Er; Guanghui Sun
      Pages: 235 - 242
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Yu Ren, Meng Joo Er, Guanghui Sun
      The exact computational problem of λ -constrained admissible average dwell time (CAADT) contractive set and CAADT invariant set for discrete-time switched systems with and without persistent amplitude-bounded additive disturbance is investigated in this paper. The considered switching signal satisfies average dwell time (ADT) and is discussed in terms of stage which is both length-based and sequence-based for the first time. Two more general criteria are established for checking the existence of the λ -average dwell time (ADT) contractive set and the ADT invariant set of the considered system by assuming the value of stage length is taken from an arbitrary finite set. A detailed discussion is included to identify a proper value for stage length by taking the computational complexity and the conservatism of the designed finite-step computational algorithms of the λ -CAADT contractive set and the CAADT invariant set into consideration. Some characteristics of the admissible λ -CAADT contractive set and CAADT invariant set are derived. An illustrative example illustrates the effectiveness of the developed results.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.059
      Issue No: Vol. 82 (2017)
       
  • Interaction of open and closed loop control in MPC
    • Authors: Karl Worthmann; Mohamed W. Mehrez; George K.I. Mann; Raymond G. Gosine; Jürgen Pannek
      Pages: 243 - 250
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Karl Worthmann, Mohamed W. Mehrez, George K.I. Mann, Raymond G. Gosine, Jürgen Pannek
      We present a novel MPC algorithm without terminal constraints and/or costs, for which the prediction horizon is reduced in comparison to standard MPC while asymptotic stability and inherent robustness properties are maintained. To this end, we derive simplified stability conditions and investigate the interplay of open and closed loop control in MPC. The insight gained from this analysis allows to close the control loop more often while keeping the computational complexity of basic MPC. Our findings are verified by numerical simulations.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.038
      Issue No: Vol. 82 (2017)
       
  • Data-injection attacks in stochastic control systems: Detectability and
           performance tradeoffs
    • Authors: Cheng-Zong Bai; Fabio Pasqualetti; Vijay Gupta
      Pages: 251 - 260
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Cheng-Zong Bai, Fabio Pasqualetti, Vijay Gupta
      Consider a stochastic process being controlled across a communication channel. The control signal that is transmitted across the control channel can be replaced by a malicious attacker. The controller is allowed to implement any arbitrary detection algorithm to detect if an attacker is present. This work characterizes some fundamental limitations of when such an attack can be detected, and quantifies the performance degradation that an attacker that seeks to be undetected or stealthy can introduce.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.047
      Issue No: Vol. 82 (2017)
       
  • The robust minimal controllability problem
    • Authors: Sérgio Pequito; Guilherme Ramos; Soummya Kar; A. Pedro Aguiar; Jaime Ramos
      Pages: 261 - 268
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Sérgio Pequito, Guilherme Ramos, Soummya Kar, A. Pedro Aguiar, Jaime Ramos
      In this paper, we address the robust minimal controllability problem, where the goal is, given a linear time-invariant system, to determine a minimal subset of state variables to be actuated to ensure controllability under additional constraints. We study the problem of characterizing the sparsest input matrices that assure controllability, when the autonomous dynamics’ matrix is simple when a specified number of inputs fail. We show that this problem is NP-hard, and under the assumption that the dynamics’ matrix is simple, we show that it is possible to reduce the problem to a set multi-covering problem. Additionally, under this assumption, we prove that this problem is NP-complete, and polynomial algorithms to approximate the solutions of a set multi-covering problem can be leveraged to obtain close-to-optimal solutions.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.053
      Issue No: Vol. 82 (2017)
       
  • Quadratic costs do not always work in MPC
    • Authors: Matthias A. Müller; Karl Worthmann
      Pages: 269 - 277
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Matthias A. Müller, Karl Worthmann
      We consider model predictive control (MPC) without terminal costs and constraints. Firstly, we rigorously show that MPC based on quadratic stage costs may fail, i.e., there does not exist a prediction horizon length such that a (controlled) equilibrium is asymptotically stable for the MPC closed loop although the system is, e.g., finite time controllable. Hence, stability properties of the infinite horizon optimal control problem are, in general, not preserved in MPC as long as purely quadratic costs are employed. This shows the necessity of using the stage cost as a design parameter to achieve asymptotic stability. Furthermore, we relax the standard controllability assumption employed in MPC without terminal costs and constraints to alleviate its verification.

      PubDate: 2017-05-23T11:45:22Z
      DOI: 10.1016/j.automatica.2017.04.058
      Issue No: Vol. 82 (2017)
       
  • Robust output regulation for invertible nonlinear MIMO systems
    • Authors: Lei Wang; Alberto Isidori; Zhitao Liu; Hongye Su
      Pages: 278 - 286
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Lei Wang, Alberto Isidori, Zhitao Liu, Hongye Su
      The robust output regulation problem for a class of invertible nonlinear MIMO systems is addressed in this paper. Under a mild assumption on the high-frequency gain matrix and strongly minimum-phase assumption, a robust regulator is proposed with the combination of nonlinear internal model and a new extended high-gain observer. More explicitly, the robust output regulation is achieved by employing a novel extended high-gain observer-based stabilizer such that the regulated system, augmented with the nonlinear internal model, is asymptotically stabilized. The novelty of this approach consists in the use of an extended observer to estimate, under mild assumptions, all unmeasured terms.

      PubDate: 2017-05-28T07:15:20Z
      DOI: 10.1016/j.automatica.2017.04.049
      Issue No: Vol. 82 (2017)
       
  • Asymptotic properties of SPS confidence regions
    • Authors: Erik Weyer; Marco Claudio Campi; Balázs Csanád Csáji
      Pages: 287 - 294
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Erik Weyer, Marco Claudio Campi, Balázs Csanád Csáji
      Sign-Perturbed Sums (SPS) is a system identification method that constructs non-asymptotic confidence regions for the parameters of linear regression models under mild statistical assumptions. One of its main features is that, for any finite number of data points and any user-specified probability, the constructed confidence region contains the true system parameter with exactly the user-chosen probability. In this paper we examine the size and the shape of the confidence regions, and we show that the regions are strongly consistent, i.e., they almost surely shrink around the true parameter as the number of data points increases. Furthermore, the confidence region is contained in a marginally inflated version of the confidence ellipsoid obtained from the asymptotic system identification theory. The results are also illustrated by a simulation example.

      PubDate: 2017-05-28T07:15:20Z
      DOI: 10.1016/j.automatica.2017.04.041
      Issue No: Vol. 82 (2017)
       
  • On global exponential stability preservation under sampling for globally
           Lipschitz time-delay systems
    • Authors: Pierdomenico Pepe; Emilia Fridman
      Pages: 295 - 300
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Pierdomenico Pepe, Emilia Fridman
      The paper shows that the global exponential stability property is preserved, under suitably fast sampling and small input-delay, whenever the dynamics of the time-delay system at hand and the related stabilizing (in continuous-time) state feedback are described by globally Lipschitz maps. The Halanay’s inequality is used in order to prove this result. Continuous-time, possibly non-affine in the control, state-delay systems are considered. The knowledge of a Lyapunov–Krasovskii functional for the continuous-time closed-loop system is not required, as long as this system is globally exponentially stable. The knowledge of a Lipschitz Lyapunov–Krasovskii functional allows for an estimation of the sampling period that preserves the exponential stability, as well as of the decay rate.

      PubDate: 2017-05-28T07:15:20Z
      DOI: 10.1016/j.automatica.2017.04.055
      Issue No: Vol. 82 (2017)
       
  • Observers for a non-Lipschitz triangular form
    • Authors: Pauline Bernard; Laurent Praly; Vincent Andrieu
      Pages: 301 - 313
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Pauline Bernard, Laurent Praly, Vincent Andrieu
      We address the problem of designing an observer for triangular non locally Lipschitz dynamical systems. We show the convergence with an arbitrary small error of the classical high gain observer in presence of nonlinearities verifying some Hölder-like condition. Also, for the case when this Hölder condition is not verified, we propose a novel cascaded high gain observer. Under slightly more restrictive assumptions, we prove the convergence of a homogeneous observer and of its cascaded version with the help of an explicit Lyapunov function.

      PubDate: 2017-05-28T07:15:20Z
      DOI: 10.1016/j.automatica.2017.04.054
      Issue No: Vol. 82 (2017)
       
  • Smooth output feedback stabilization of a class of planar switched
           nonlinear systems under arbitrary switchings
    • Authors: Xiangze Lin; Chih-Chiang Chen; Chunjiang Qian
      Pages: 314 - 318
      Abstract: Publication date: August 2017
      Source:Automatica, Volume 82
      Author(s): Xiangze Lin, Chih-Chiang Chen, Chunjiang Qian
      Smooth output feedback stabilization problem for a family of planar switched nonlinear systems is addressed. First, based on the adding a power integrator technique, the tasks of finding a common Lyapunov function and designing state feedback stabilizing control laws are accomplished simultaneously. Then, combining the state feedback control laws and the reduced-order nonlinear observers, output feedback control laws are designed to globally stabilize the switched nonlinear system under arbitrary switchings, whose subsystems may have uncontrollable/unobservable Jacobian linearizations.

      PubDate: 2017-06-12T07:36:52Z
      DOI: 10.1016/j.automatica.2017.03.020
      Issue No: Vol. 82 (2017)
       
  • Étale backstepping for control Lyapunov function design on manifold
    • Abstract: Publication date: September 2017
      Source:Automatica, Volume 83
      Author(s): Hisakazu Nakamura, Yasuyuki Satoh
      Backstepping is one of the most popular nonlinear controller and differentiable control Lyapunov function (CLF) design techniques. However, for asymptotic stabilization of systems defined on noncontractible manifolds, there exists no differentiable CLF; the semiconcave CLF design problem based on the backstepping has not been discussed. In this paper, we propose a backstepping based controller design method for asymptotic stabilization of systems defined on noncontractible manifolds. In the method, we design a controller and a CLF on an étale space. Then, we obtain a semiconcave CLF on the original space by the minimum projection method. The effectiveness of the proposed method is confirmed by computer simulation.

      PubDate: 2017-06-22T07:41:50Z
       
 
 
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