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COMPUTER SCIENCE (1169 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: 14)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 24)
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: 15)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 6)
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: 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: 9)
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: 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: 15)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 52)
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: 21)
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: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 4)
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: 8)
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: 2)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 15)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
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: 131)
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: 9)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 298)
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: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 131)
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: 2)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access   (Followers: 1)
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: 11)
Circuits and Systems     Open Access   (Followers: 15)
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: 14)
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: 55)
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   (Followers: 1)
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: 22)
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: 14)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 30)
Computer     Full-text available via subscription   (Followers: 89)
Computer Aided Surgery     Hybrid Journal   (Followers: 5)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 9)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 22)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 12)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 2)
Computer Music Journal     Hybrid Journal   (Followers: 18)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computer Science and Information Technology     Open Access   (Followers: 13)
Computer Science Education     Hybrid Journal   (Followers: 14)
Computer Science Journal     Open Access   (Followers: 21)

        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  [3118 journals]
  • Circular formation of networked dynamic unicycles by a distributed dynamic
           control law
    • Authors: Xiao Yu; Xiang Xu; Lu Liu; Gang Feng
      Pages: 1 - 7
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Xiao Yu, Xiang Xu, Lu Liu, Gang Feng
      This paper investigates the circular formation control problem of networked dynamic unicycles. Each unicycle uses its local coordinate frame and the topology of the networked unicycles is modeled by a directed graph containing a spanning tree. A distributed dynamic control law is proposed for each unicycle based on the measurement via local sensing and the information of its neighbors via intermittent communication. It is shown that all unicycles can globally converge to the circular motion around a given center which is only known to one unicycle, and can globally converge to a desired spaced formation along the circle. Finally, simulation results of an example verify the effectiveness of the proposed control law.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.021
      Issue No: Vol. 89 (2017)
  • Stability structures of conjunctive Boolean networks
    • Authors: Zuguang Gao; Xudong Chen; Tamer Başar
      Pages: 8 - 20
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Zuguang Gao, Xudong Chen, Tamer Başar
      A Boolean network is a finite dynamical system, whose variables take values from a binary set. The value update rule for each variable is a Boolean function, depending on a selected subset of variables. Boolean networks have been widely used in modeling gene regulatory networks. We focus in this paper on a special class of Boolean networks, termed as conjunctive Boolean networks. A Boolean network is conjunctive if the associated value update rule is comprised of only AND operations. It is known that any trajectory of a finite dynamical system will enter a periodic orbit. We characterize in this paper all periodic orbits of a conjunctive Boolean network whose underlying graph is strongly connected. In particular, we establish a bijection between the set of periodic orbits and the set of binary necklaces of a certain length. We further investigate the stability of a periodic orbit. Specifically, we perturb a state in the periodic orbit by changing the value of a single entry of the state. The trajectory, with the perturbed state being the initial condition, will enter another (possibly the same) periodic orbit in finite time steps. We then provide a complete characterization of all such transitions from one periodic orbit to another. In particular, we construct a digraph, with the vertices being the periodic orbits, and the (directed) edges representing the transitions among the orbits. We call such a digraph the stability structure of the conjunctive Boolean network.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.017
      Issue No: Vol. 89 (2017)
  • Robust finite-time connectivity preserving coordination of second-order
           multi-agent systems
    • Authors: Chao Sun; Guoqiang Hu; Lihua Xie; Magnus Egerstedt
      Pages: 21 - 27
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Chao Sun, Guoqiang Hu, Lihua Xie, Magnus Egerstedt
      In this paper, we consider robust finite-time connectivity preserving coordination problems for second-order multi-agent systems with limited sensing range. Based on integral sliding mode control and artificial potential field, a distributed controller is developed to achieve robust finite-time consensus and meanwhile maintain the connectivity of the communication network. The method is further extended to address a finite-time formation tracking control problem. Numerical examples are given to show the effectiveness of the proposed methods.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.020
      Issue No: Vol. 89 (2017)
  • Efficient path planning algorithms in reach-avoid problems
    • Authors: Zhengyuan Zhou; Jerry Ding; Haomiao Huang; Ryo Takei; Claire Tomlin
      Pages: 28 - 36
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Zhengyuan Zhou, Jerry Ding, Haomiao Huang, Ryo Takei, Claire Tomlin
      We consider a multi-player differential game, referred to as a reach-avoid game, in which one set of attacking players attempts to reach a target while avoiding both obstacles and capture by a set of defending players. Unlike pursuit–evasion games, in this reach-avoid game one set of players must not only consider the other set of players, but also the target. This complexity makes finding solutions to such games computationally challenging, especially as the number of players grows. We propose an approach to solving such games in an open-loop sense, where the players commit to their control actions prior to the beginning of the game. This reduces the dimensionality of the required computations, thus enabling efficient computation of feasible solutions in real time for domains with arbitrary obstacle topologies. We describe two such formulations, each of which is conservative towards one side, and derive numerical algorithms based upon modified fast-marching methods (FMM) for computing their solutions.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.035
      Issue No: Vol. 89 (2017)
  • Informative input design for Kernel-Based system identification
    • Authors: Yusuke Fujimoto; Toshiharu Sugie
      Pages: 37 - 43
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Yusuke Fujimoto, Toshiharu Sugie
      This paper discusses the design of input sequence for Kernel-Based system identification. From the Bayesian point of view, the kernel reflects a priori information about the target system, which implies that the information obtained from I/O data differs over kernels. This paper focuses on finding an input sequence which maximizes the information obtained through an observation according to the kernel which is given in advance. As an appropriate measure of such information, the mutual information is adopted. For the given kernel, a concrete procedure is proposed to find the input sequence maximizing the mutual information subject to the input energy constraints. Numerical examples are given to illustrate the effectiveness of the proposed input design. Furthermore, it is shown analytically that the impulse input is optimal for a special class of kernels.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.019
      Issue No: Vol. 89 (2017)
  • Boundary feedback control of linear hyperbolic systems: Application to the
           Saint-Venant–Exner equations
    • Authors: Christophe Prieur; Joseph J. Winkin
      Pages: 44 - 51
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Christophe Prieur, Joseph J. Winkin
      Distributed parameter systems modeled by hyperbolic partial differential equations are considered in this paper. The dynamic models include a source term and heterodirectional velocities. A boundary control problem is introduced and it is first shown that it is well-posed (in the sense of Tucsnak and Weiss), under appropriate assumptions coupling the boundary conditions and the source term. Then a sufficient exponential stability condition is derived using operator theory. This condition is written in terms of Linear Matrix Inequalities that are numerically tractable and that allow an optimization program. Connections with another classical stability condition are given. This approach is applied to the Saint-Venant–Exner equation describing the dynamics of the water level, of the water flow and of the sediment inside of a channel. The effect of the friction and of the slope are taken into account in the application model.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.028
      Issue No: Vol. 89 (2017)
  • Stochastic control for optical manipulation of multiple microscopic
    • Authors: Quang Minh Ta; Chien Chern Cheah
      Pages: 52 - 64
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Quang Minh Ta, Chien Chern Cheah
      While various control techniques have been developed for optical manipulation, the Brownian movement of microscopic objects in the medium is usually ignored for simplicity of analyzing the control systems. Nevertheless, due to the universality of the Brownian movement and its effect on optical manipulation of cells or micro-objects, it is required for the Brownian effect to be properly taken into consideration so as to ensure the stability and performance of the control systems. In this paper, we derive a stochastic control technique to achieve a theoretical framework for optical manipulation of multiple microscopic objects in the presence of the Brownian perturbations. In the proposed control methodology, a region control technique and a dynamic interaction approach are developed for collision-free manipulation of the target micro-objects with random perturbations. All the target micro-objects are trapped and manipulated simultaneously while being kept inside the desired dynamic region, and at the same time, preserving a minimum distance with each other to avoid collisions. While a bounded tracking or region error exists in current control techniques for optical manipulation due to the effect of the Brownian perturbations, this paper provides a new approach which guarantees that all the target micro-objects are kept inside the desired region during the course of manipulation. Rigorous mathematical formulation has been developed for automated manipulation of multiple microscopic objects in the presence of the Brownian perturbations, and experimental results are presented to demonstrate the feasibility and effectiveness of the proposed control technique.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.031
      Issue No: Vol. 89 (2017)
  • State-feedback control of Markov jump linear systems with hidden-Markov
           mode observation
    • Authors: Masaki Ogura; Ahmet Cetinkaya; Tomohisa Hayakawa; Victor M. Preciado
      Pages: 65 - 72
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Masaki Ogura, Ahmet Cetinkaya, Tomohisa Hayakawa, Victor M. Preciado
      In this paper, we study state-feedback control of Markov jump linear systems with partial information about the mode signal responsible for switching between dynamic modes. We assume that the controller can only access random samples of the mode signal according to a hidden-Markov observation process. Our formulation provides a novel framework to analyze and design feedback control laws for various Markov jump linear systems previously studied in the literature, such as the cases of (i) clustered observations, (ii) detector-based observations, and (iii) periodic observations. We present a procedure to transform the closed-loop system with hidden-Markov observations into a standard Markov jump linear system while preserving stability, H 2 norm, and  H ∞  norm. Furthermore, based on this transformation, we propose a set of Linear Matrix Inequalities (LMI) to design feedback control laws for stabilization, H 2 suboptimal control, and  H ∞ suboptimal control of discrete-time Markov jump linear systems under hidden-Markov observations of the mode signals. We conclude by illustrating our results with some numerical examples.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.022
      Issue No: Vol. 89 (2017)
  • Global optimization for low-dimensional switching linear regression and
           bounded-error estimation
    • Authors: Fabien Lauer
      Pages: 73 - 82
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Fabien Lauer
      The paper provides global optimization algorithms for two particularly difficult nonconvex problems raised by hybrid system identification: switching linear regression and bounded-error estimation. While most works focus on local optimization heuristics without global optimality guarantees or with guarantees valid only under restrictive conditions, the proposed approach always yields a solution with a certificate of global optimality. This approach relies on a branch-and-bound strategy for which we devise lower bounds that can be efficiently computed. In order to obtain scalable algorithms with respect to the number of data, we directly optimize the model parameters in a continuous optimization setting without involving integer variables. Numerical experiments show that the proposed algorithms offer a higher accuracy than convex relaxations with a reasonable computational burden for hybrid system identification. In addition, we discuss how bounded-error estimation is related to robust estimation in the presence of outliers and exact recovery under sparse noise, for which we also obtain promising numerical results.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.026
      Issue No: Vol. 89 (2017)
  • A peak-over-threshold search method for global optimization
    • Authors: Siyang Gao; Leyuan Shi; Zhengjun Zhang
      Pages: 83 - 91
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Siyang Gao, Leyuan Shi, Zhengjun Zhang
      In this paper, we propose a random search method, called peak-over-threshold search (POTS), for solving global optimization problems. An important feature of POTS is that it combines the existing partition-based random search framework (e.g., Shi and Ólafsson 2000a; Chen et al. 2011) with the peak-over-threshold statistical reference (Coles, 2001) in order to achieve high search efficiency. In each iteration, POTS partitions the solution space into several subregions, evaluates the quality of each subregion and moves to promising subregions for more partitioning and sampling. To effectively assess the quality of a subregion, an extreme value type of inference in statistics is used to develop a new promising index which reflects the optimal objective value of a subregion and biases the search to regions that are likely to contain the optimal or near-optimal solutions. Under assumptions on the depth of partitioning and the probability of correct movement, POTS is shown to converge with probability one to the optimal region. The higher efficiency of the proposed method is illustrated by numerical examples. The application of POTS to beam angle selection, an important optimization problem in radiation treatment, is also presented in this paper.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.12.002
      Issue No: Vol. 89 (2017)
  • Practical closed-loop dynamic pricing in smart grid for supply and demand
    • Authors: Jianping He; Chengcheng Zhao; Lin Cai; Peng Cheng; Ling Shi
      Pages: 92 - 102
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Jianping He, Chengcheng Zhao, Lin Cai, Peng Cheng, Ling Shi
      Pricing strategy for power systems is an important and challenging problem, due to the difficulties in predicting the demand and the reactions of customers to the price accurately. Any prediction errors may result in higher costs to the supplier. To address this issue, in this paper, we propose a novel, practical closed-loop pricing algorithm (PCPA). Using the closed-loop control to well coordinate the customers and the supplier, the power system can run more efficiently, resulting in both cost saving for customers and higher profit for the supplier. We prove the convergence of PCPA, i.e., a stable price can be achieved. We provide sufficient conditions to guarantee the win-win solution for both the customers and the supplier, and an upper bound of the gain. We also provide a necessary and sufficient condition of that the highest win for both the customers and the supplier can be achieved. Extensive simulations have shown that PCPA can outperform the existing prediction-based pricing algorithms. It shows that the profit gain of the proposed algorithm can up to 100% when the total demand can be fixed to the optimal demand.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.011
      Issue No: Vol. 89 (2017)
  • Bilinear Hamiltonian interactions between linear quantum systems via
    • Authors: Symeon Grivopoulos; Ian R. Petersen
      Pages: 103 - 110
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Symeon Grivopoulos, Ian R. Petersen
      A number of recent works employ bilinear Hamiltonian interactions between Linear Quantum Stochastic Systems (LQSSs). To the authors’ knowledge, implementation schemes for such interactions exist only between single-mode systems. In this work, we propose a general method for the implementation of an arbitrary bilinear Hamiltonian interaction between two multi-mode LQSSs via a feedback interconnection. As an application, we show that the direct interaction realization of a certain coherent quantum control architecture is very useful for design and optimization.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.002
      Issue No: Vol. 89 (2017)
  • The partial pinning control strategy for large complex networks
    • Authors: Pietro DeLellis; Franco Garofalo; Francesco Lo Iudice
      Pages: 111 - 116
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Pietro DeLellis, Franco Garofalo, Francesco Lo Iudice
      In large directed complex networks, it may result unfeasible to successfully pinning control the whole network. Indeed, when the pinner node can be connected only to a limited number of nodes, it may be impossible to guarantee pinning controllability of all the network nodes. In this paper, we introduce the partial pinning control problem, which consists in determining the optimal selection of the nodes to be pinned so as to maximize the fraction of nodes of the whole network that can be asymptotically controlled to the pinner’s trajectory. A suboptimal solution to this problem is provided for a class of nonlinear node dynamics, together with the bounds on the minimum coupling and control gains required to “partially control” the network. The theoretical analysis is translated into an integer linear program (ILP), which is solved on a testbed network of 688 nodes.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.025
      Issue No: Vol. 89 (2017)
  • Worst-case stealthy innovation-based linear attack on remote state
    • Authors: Ziyang Guo; Dawei Shi; Karl Henrik Johansson; Ling Shi
      Pages: 117 - 124
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Ziyang Guo, Dawei Shi, Karl Henrik Johansson, Ling Shi
      In this work, a security problem in cyber–physical systems is studied. We consider a remote state estimation scenario where a sensor transmits its measurement to a remote estimator through a wireless communication network. The Kullback–Leibler divergence is adopted as a stealthiness metric to detect system anomalies. We propose an innovation-based linear attack strategy and derive the remote estimation error covariance recursion in the presence of attack, based on which a two-stage optimization problem is formulated to investigate the worst-case attack policy. It is proved that the worst-case attack policy is zero-mean Gaussian distributed and the numerical solution is obtained by semi-definite programming. Moreover, an explicit algorithm is provided to calculate the compromised measurement. The trade-off between attack stealthiness and system performance degradation is evaluated via simulation examples.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.018
      Issue No: Vol. 89 (2017)
  • Cascade observer design for a class of uncertain nonlinear systems with
           delayed outputs
    • Authors: Mondher Farza; Omar Hernández-González; Tomas Ménard; Boubekeur Targui; Mohammed M’Saad; Carlos-Manuel Astorga-Zaragoza
      Pages: 125 - 134
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Mondher Farza, Omar Hernández-González, Tomas Ménard, Boubekeur Targui, Mohammed M’Saad, Carlos-Manuel Astorga-Zaragoza
      This paper proposes a state observer with a cascade structure for a class of nonlinear systems in the presence of uncertainties in the state equations and an arbitrarily long delay in the outputs. The design of the observer is achieved under an appropriate set of assumptions allowing to establish the ultimate boundedness of the observation error. Indeed, a suitable expression of the asymptotic observation error, involving the delay, the bound of the uncertainties and the Lipschitz constant of the system nonlinearities, is derived. Besides, it is shown that this ultimate bound is a decreasing function of the cascade length and is equal to zero in the uncertainty-free case. The observer design is first carried out in the case where the output measurements are continuously available and subsequently extended to the case where the outputs are available only at (non equally spaced) sampling instants. The performance of the proposed observer and its main properties are highlighted through illustrative simulation results involving an academic example.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.12.012
      Issue No: Vol. 89 (2017)
  • Point-to-point iterative learning model predictive control
    • Authors: Se-Kyu Oh; Byung Jun Park; Jong Min Lee
      Pages: 135 - 143
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Se-Kyu Oh, Byung Jun Park, Jong Min Lee
      Iterative learning model predictive control (ILMPC) is a technique that combines iterative learning control (ILC) and model predictive control (MPC). The objective is to track a reference trajectory of repetitive processes on a finite time interval while rejecting real-time disturbances. In many repetitive processes, the output is not required to track all the points of a reference trajectory. In this study, we propose a point-to-point ILMPC (PTP ILMPC) technique considering only the desired reference points, and not an entire reference trajectory. In this method, an arbitrary reference trajectory passing through the desired reference values need not be generated. Numerical examples are provided to demonstrate the performances of the suggested approach in terms of PTP tracking, iterative learning, constraint handling, and real-time disturbance rejection.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.010
      Issue No: Vol. 89 (2017)
  • Consensus control for a network of high order continuous-time agents with
           communication delays
    • Authors: Lin Li; Minyue Fu; Huanshui Zhang; Renquan Lu
      Pages: 144 - 150
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Lin Li, Minyue Fu, Huanshui Zhang, Renquan Lu
      This paper is concerned with the consensus control problem for multi-agent systems with agents characterized by high-order linear continuous-time systems subject to communication delays between neighbouring nodes in the network. A new consensus protocol is proposed. It requires communication between neighbouring agents only at certain sampling points, rather than at all times. It is also unique in the sense that it is nonlinear in the continuous-time domain but linear when the agents are viewed in the sampled-data domain. Under the proposed consensus protocol, marginally stable multi-agent systems can reach consensus for any large delay. Unstable multi-agent systems achieve consensus when the time delay is within a certain range. Moreover, in the single-input case, we give an optimal control gain which yields the fastest consensus speed. The proposed technique is expected to pave a new way for new theoretical studies on network properties required for consensus control.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.12.006
      Issue No: Vol. 89 (2017)
  • Universal strategies to explicit adaptive control of nonlinear time-delay
           systems with different structures
    • Authors: Zhen-Guo Liu; Yu-Qiang Wu
      Pages: 151 - 159
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Zhen-Guo Liu, Yu-Qiang Wu
      The adaptive control problem of high-order time-delay nonlinear systems with lower-triangular or upper-triangular structure is studied in this paper. Remarkably, by using the function scaling gain strategy and homogeneous domination method, two kinds of explicit universal adaptive controllers are designed such that all the states of the closed-loop system are globally bounded and the solutions of the original system converge to zero. The robust adaptive controller is also designed by employing the σ -modification method. Examples are provided to demonstrate the validness of the theory.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.023
      Issue No: Vol. 89 (2017)
  • Dominant eigenvalue minimization with trace preserving diagonal
           perturbation: Subset design problem
    • Authors: Jackeline Abad Torres; Sandip Roy
      Pages: 160 - 168
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Jackeline Abad Torres, Sandip Roy
      Motivated by network resource allocation needs, we study the problem of minimizing the dominant eigenvalue of an essentially-nonnegative matrix with respect to a trace-preserving or fixed-trace diagonal perturbation, in the case where only a subset of the diagonal entries can be perturbed. Graph-theoretic characterizations of the optimal subset design are obtained: in particular, the design is connected to the structure of a reduced effective graph defined from the essentially-nonnegative matrix. Also, the change in the optimum is studied when additional diagonal entries are constrained to be undesignable, from both an algebraic and graph-theoretic perspective. These results are developed in part using properties of the Perron complement of nonnegative matrices, and the concept of line-sum symmetry. Some results apply to general essentially-nonnegative matrices, while others are specialized for sub-classes (e.g., diagonally-symmetrizable, or having a single node cut).

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.12.007
      Issue No: Vol. 89 (2017)
  • Optimal identification experiment design for the interconnection of
           locally controlled systems
    • Authors: Xavier Bombois; Anton Korniienko; Håkan Hjalmarsson; Gérard Scorletti
      Pages: 169 - 179
      Abstract: Publication date: March 2018
      Source:Automatica, Volume 89
      Author(s): Xavier Bombois, Anton Korniienko, Håkan Hjalmarsson, Gérard Scorletti
      This paper considers the identification of the modules of a network of locally controlled systems (multi-agent systems). Its main contribution is to determine the least perturbing identification experiment that will nevertheless lead to sufficiently accurate models of each module for the global performance of the network to be improved by a redesign of the decentralized controllers. Another contribution is to determine the experimental conditions under which sufficiently informative data (i.e. data leading to a consistent estimate) can be collected for the identification of any module in such a network.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.12.014
      Issue No: Vol. 89 (2017)
  • 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
    • 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)
  • State-space LPV model identification using kernelized machine learning
    • Authors: Syed Zeeshan Rizvi; Javad Mohammadpour Velni; Farshid Abbasi; Roland Tóth; Nader Meskin
      Pages: 38 - 47
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Syed Zeeshan Rizvi, Javad Mohammadpour Velni, Farshid Abbasi, Roland Tóth, Nader Meskin
      This paper presents a nonparametric method for identification of MIMO linear parameter-varying (LPV) models in state-space form. The states are first estimated up to a similarity transformation via a nonlinear canonical correlation analysis (CCA) operating in a reproducing kernel Hilbert space (RKHS). This enables to reconstruct a minimal-dimensional inference between past and future input, output and scheduling variables, making it possible to estimate a state sequence consistent with the data. Once the states are estimated, a least-squares support vector machine (LS-SVM)-based identification scheme is formulated, allowing to capture the dependency structure of the matrices of the estimated state-space model on the scheduling variables without requiring an explicit declaration of these often unknown dependencies; instead, it only requires the selection of nonlinear kernel functions and the tuning of the associated hyper-parameters.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.004
      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)
  • Cartesian product-based hierarchical scheme for multi-agent systems
    • Authors: Muhammad Iqbal; John Leth; Trung Dung Ngo
      Pages: 70 - 75
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Muhammad Iqbal, John Leth, Trung Dung Ngo
      In this paper, we solve the average-consensus problem using a hierarchical scheme based on Cartesian product of strongly connected balanced graphs — an algebraic approach to design complex networks. We show that the Cartesian product based hierarchical scheme for multi-agent systems outperforms the single-layer control strategies for average-consensus problem in terms of convergence rate, and also the system matrix produced by Cartesian product-based hierarchical (CPH) scheme do not necessarily exhibit block circulant symmetry. We analyze that if the factors graphs in Cartesian product are cyclic pursuit graphs, then the CPH scheme provides the same convergence rate while requiring the same communication links as in the hierarchical cyclic pursuit (HCP). We provide simulation results to demonstrate the key theoretical results.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.009
      Issue No: Vol. 88 (2017)
  • Asymptotic stabilization of continuous-time linear systems with quantized
           state feedback
    • Authors: Jian Wang
      Pages: 83 - 90
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Jian Wang
      This paper considers an asymptotic stabilization problem of continuous-time linear systems subject to state quantization. Based on spherical polar coordinates, a quantizer is proposed with a desired relation between the quantized data and the corresponding quantization error for this problem. Owing to the quantization error the resulting closed-loop system is described by a discontinuous right-hand side differential equation and the notion of Krasovskii solution is adopted for the equation. By the proposed quantizer, a time-invariant coding scheme is first proposed and further a state feedback controller is designed to achieve convergence of the closed-loop trajectories toward a compact surface surrounding the origin, on which sliding motion occurs. Then, a time-varying coding scheme is proposed to avoid chattering phenomena induced by the sliding motion on the surface and achieve asymptotic stability of systems.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.027
      Issue No: Vol. 88 (2017)
  • Some insights into the migration of double imaginary roots under small
           deviation of two parameters
    • Authors: Dina Alina Irofti; Keqin Gu; Islam Boussaada; Silviu-Iulian Niculescu
      Pages: 91 - 97
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Dina Alina Irofti, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu
      This paper studies the migration of double imaginary roots of the systems’ characteristic equation when two parameters are subjected to small deviations. The proposed approach covers a wide range of models. Under the least degeneracy assumptions, we found that the local stability crossing curve has a cusp at the point that corresponds to the double root, and it divides the neighborhood of this point into an S-sector and a G-sector. When the parameters move into the G-sector, one of the roots moves to the right half-plane, and the other moves to the left half-plane. When the parameters move into the S-sector, both roots move either to the left half-plane or the right half-plane depending on the sign of a quantity that depends on the characteristic function and its derivatives up to the third order.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.015
      Issue No: Vol. 88 (2017)
  • On optimal system operation in robust economic MPC
    • Authors: Florian A. Bayer; Matthias A. Müller; Frank Allgöwer
      Pages: 98 - 106
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Florian A. Bayer, Matthias A. Müller, Frank Allgöwer
      In this paper, different approaches for economic MPC under disturbances are investigated with respect to their optimal operating behavior. We derive dissipativity-based conditions under which certain optimal operating regimes can be guaranteed for the considered setups. Depending on the information about the disturbance, the system, and the algorithmic structure of the considered underlying robust economic MPC scheme, different statements can be derived. These include, inter alia, statements on stochastic and robust optimal operation. Moreover, we are able to provide converse statements showing – under a certain controllability assumption – necessity of the dissipativity statements for optimal operation at steady-state.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.007
      Issue No: Vol. 88 (2017)
  • A new frequency weighted Fourier-based method for model order reduction
    • Authors: Marek Rydel; Rafał Stanisławski
      Pages: 107 - 112
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Marek Rydel, Rafał Stanisławski
      This paper presents a new, analytically driven frequency weighted model order reduction method. The method is grounded on the Fourier-based decomposition of a high-order state space model. The method is designed for discrete-time systems, but it can be easily applied to continuous-time ones. The main advantage of the proposed algorithm is a class of quadratic time complexity as compared to the cubic one for the classical frequency weighted method, the major feature resulting from the application of analytical methods for calculation of factorizations for controllability and observability Gramians. The simulation experiment confirms the effectiveness of the proposed method both in terms of high modeling accuracy and low computational cost.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.11.016
      Issue No: Vol. 88 (2017)
  • Output regulation for systems on matrix Lie-groups
    • Authors: Simone de Marco; Lorenzo Marconi; Robert Mahony; Tarek Hamel
      Pages: 8 - 16
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Simone de Marco, Lorenzo Marconi, Robert Mahony, Tarek Hamel
      This paper deals with the problem of output regulation for left invariant systems defined on general matrix Lie-Groups. Reference trajectories to be tracked are generated by a right invariant exosystem defined on the same Lie-Group and driven by a linear oscillator defined on the Lie-algebra. Only partial relative geometrical information of the exosystem with respect to actual system is available in the form of invariant measurements in a homogeneous space, a quotient of the Lie-group. In the spirit of the internal model principle, the proposed control structure contains an embedded copy of the exosystem kinematics. The dynamics associated with the mechanical systems can be handled by dynamic extension of the proposed control approach. We demonstrate the approach by providing the details of this extension for the specific case of rotational dynamics on S O ( 3 ) . The problem formulation considered is motivated by a wide range of real applications in robotics, aerospace, and computer vision, where the state space of systems such as mobile robots, aerial robots, unmanned drones, and camera homographies are naturally Lie-groups associated with inherent symmetry properties of the underlying physical system.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.08.006
      Issue No: Vol. 87 (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
    • 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)
  • 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)
  • 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 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)
  • 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)
  • 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)
  • 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)
  • 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)
  • Funnel control for nonlinear systems with known strict relative degree
    • Authors: Thomas Berger; Huy Hoàng Lê; Timo Reis
      Pages: 345 - 357
      Abstract: Publication date: January 2018
      Source:Automatica, Volume 87
      Author(s): Thomas Berger, Huy Hoàng Lê, Timo Reis
      We consider tracking control for uncertain nonlinear multi-input, multi-output systems which have arbitrary strict relative degree and input-to-state stable internal dynamics. For a given sufficiently smooth reference signal, our aim is to design a low-complexity model-free controller which achieves that the tracking error evolves within a prespecified performance funnel. To this end, we introduce a new controller which involves the first  r − 1 derivatives of the tracking error, where  r is the strict relative degree of the system. We derive an explicit bound for the resulting input and discuss the influence of the controller parameters. We further present some simulations where our funnel controller is applied to a mechanical system with higher relative degree and a two-input, two-output robot manipulator. The controller is also compared with other approaches.

      PubDate: 2017-12-27T01:39:22Z
      DOI: 10.1016/j.automatica.2017.10.017
      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)
  • Mean–variance optimization of discrete time discounted Markov
           decision processes
    • Authors: Xia
      Abstract: Publication date: February 2018
      Source:Automatica, Volume 88
      Author(s): Li Xia
      In this paper, we study a mean–variance optimization problem in an infinite horizon discrete time discounted Markov decision process (MDP). The objective is to minimize the variance of system rewards with the constraint of mean performance. Different from most of works in the literature which require the mean performance already achieve optimum, we can let the discounted performance equal any constant. The difficulty of this problem is caused by the quadratic form of the variance function which makes the variance minimization problem not a standard MDP. By proving the decomposable structure of the feasible policy space, we transform this constrained variance minimization problem to an equivalent unconstrained MDP under a new discounted criterion and a new reward function. The difference of the variances of Markov chains under any two feasible policies is quantified by a difference formula. Based on the variance difference formula, a policy iteration algorithm is developed to find the optimal policy. We also prove the optimality of deterministic policy over the randomized policy generated in the mean-constrained policy space. Numerical experiments demonstrate the effectiveness of our approach.

      PubDate: 2017-12-27T01:39:22Z
  • 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
  • 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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Heriot-Watt University
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