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Variable speed control in wells turbine-based oscillating water column devices: optimum rotational speed

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Variable speed control in wells turbine-based oscillating wa...

2017年第六届电力科学与工程国际会议

作者： J Lekube A J Garrido I Garrido Automatic Control Group (ACG). Institute of Research and Development of Processes (IIDP). Department of Automatic Control and Systems Engineering Faculty of Engineering of Bilbao University of the Basque Country (UPV/EHU)

The effects of climate change and global warming reveal the need to find alternative sources of clean energy. In this sense, wave energy power plants, and in particular Oscillating Water Column(OWC) devices, offer a huge potential of energy harnessing. Nevertheless, the conversion systems have not reached a commercially mature stage yet so as to compete with conventional power plants. At this point, the use of new control methods over the existing technology arises as a doable way to improve the efficiency of the system. Due to the nonuniform response that the turbine shows to the rotational speed variation, the speed control of the turbo-generator may offer a feasible solution for efficiency improvement during the energy conversion. In this context, a novel speed control approach for OWC systems is presented in this paper, demonstrating its goodness and affording promising results when particularized to the Mutriku's wave power plant.

关键词： Variable speed control in wells turbine-based oscillating water column devices optimum rotational speed

A note on the stability analysis of a class of nonlinear systems - An LMI approach

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UPB Scientific Bulletin, Series C: Electrical Engineering an...

UPB Scientific Bulletin, Series C: Electrical engineering and Computer Science 2018年第4期80卷 3-10页

作者： Olteanu, Mircea Ştefan, Radu Department of Mathematical Methods and Models Faculty of Applied Sciences University "Politehnica" of Bucharest Romania Department of Automatic Control and Systems Engineering Faculty of Automatic Control and Computer Science University "Politehnica" of Bucharest Romania

The main goal of the paper is to study the equilibria of a nonlinear system, proving the existence and uniqueness of an equilibrium point in the positive ortant. We also provide numerically tractable conditions (by using Linear Matrix Inequalities techniques) to check the asymptotic stability of the equilibrium point. An illustrative numerical example is closing the paper along with some conclusions. © 2018, Politechnica University of Bucharest. All rights reserved.

关键词： Nonlinear systems

Fast spread in controlled evolutionary dynamics

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arXiv 2019年

作者： Zino, Lorenzo Como, Giacomo Fagnani, Fabio Department of Mathematical Sciences G.L. Lagrange Politecnico di Torino Torino10129 Italy Faculty of Science and Engineering University of Groningen 9747 AG Groningen Netherlands Department of Automatic Control Lund University BOX 118 Lund22100 Sweden

We study the spread of a novel state in a network in the presence of an exogenous control. The controlled evolutionary dynamics model we study is a non-homogeneous Markov process describing the evolution of the states of all nodes in the network. Through a rigorous analysis of this system, we establish upper and lower bounds on the expected time needed for the novel state to replace the original one. Such bounds are in terms of the features of the control policy (specifically, the set of nodes that can be controlled and its energy) and of the network topology. Leveraging these results, we are able to classify network structures depending on their controllability. Finally, we propose a feedback control policy that, using little knowledge of the network topology and of the system's evolution at a macroscopic level, allows for a substantial speed up of the spreading process. All these theoretical results are presented together with explanatory examples, for which Monte Carlo simulations corroborate our analytical findings. Copyright © 2019, The Authors. All rights reserved.

关键词： Feedback control

Distributed algorithms that solve boolean equations with local and differential privacies

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arXiv 2020年

作者： Qi, Hongsheng Li, Bo Jing, Rui-Juan Wang, Lei Proutiere, Alexandre Shi, Guodong Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Mathematics Mechanization Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Faculty of Science Jiangsu University Zhenjiang212013 China Australian Center for Field Robotics School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW2006 Australia Department of Automatic Control Kth Royal Institute of Technology Stockholm100-44 Sweden

In this paper, we propose distributed algorithms that solve a system of Boolean equations over a network, where each node in the network possesses only one Boolean equation from the system. The Boolean equation assigned at any particular node is a private equation known to this node only, and the nodes aim to compute the exact set of solutions to the system without exchanging their local equations. We show that each private Boolean equation can be locally lifted to a linear algebraic equation under a basis of Boolean vectors, leading to a network linear equation that is distributedly solvable using existing distributed linear equation algorithms as a subroutine. A number of exact or approximate solutions to the induced linear equation are then computed at each node from different initial values. The solutions to the original Boolean equations are eventually computed locally via a Boolean vector search algorithm. We prove that given solvable Boolean equations, when the initial values of the nodes for the distributed linear equation solving step are i.i.d selected according to a uniform distribution in a high-dimensional cube, our algorithms return the exact solution set of the Boolean equations at each node with high probability. Furthermore, we present an algorithm for distributed verification of the satisfiability of Boolean equations, and prove its correctness. Finally, we show that by utilizing linear equation solvers with differential privacy to replace the in-network computing routines, the overall distributed Boolean equation algorithms can be made differentially private. Under the standard Laplace mechanism, we prove an explicit level of noises that can be injected in the linear equation steps for ensuring a prescribed level of differential privacy. Copyright © 2020, The Authors. All rights reserved.

关键词： Linear equations

Considerations regarding security issues impact on systems availability

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arXiv 2018年

作者： Pricop, Emil Mihalache, Sanda Florentina Paraschiv, Nicolae Fattahi, Jaouhar Zamfir, Florin Automatic Control Computers and Electronics Department Petroleum-Gas University of Ploiesti Ploiesti Romania Dept. of Computer Science and Software Engineering Université Laval QC Canada Automatic Control Computers and Electronics Dept. Petroleum-Gas University of Ploiesti Ploiesti Romania

control systems behavior can be analyzed taking into account a large number of parameters: Performances, reliability, availability, security. Each control system presents various security vulnerabilities that affect in lower or higher measure its functioning. In this paper the authors present a method to assess the impact of security issues on the systems availability. A fuzzy model for estimating the availability of the system based on the security level and achieved availability coefficient (depending on MTBF and MTR) is developed and described. The results of the fuzzy inference system (FIS) are presented in the last section of the paper. Copyright © 2018, The Authors. All rights reserved.

关键词： Availability

Modeling an ANN-based control for optimal operation of PEMFC systems

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Modeling an ANN-based control for optimal operation of PEMFC...

International Conference on Electronics, computers and Artificial Intelligence (ECAI)

作者： Jose Manuel Lopez-Guede Nicu Bizon Systems Engineering and Automatic Control Department University of the Basque Country (UPV/ EHU) Vitoria Spain Faculty of Electronics Communication and Computers University of Pitesti Pitesti Romania

ISBN: (纸本)9781538649022;9781538649015

In the field of the proton exchange membrane fuel cells (PEMFCs), the main objectives of a control strategy are to optimize the electrochemical reactions in the reaction subsystem in order to increase the fuel economy and energy efficiency, as well as ensure the load demand under a dynamic load profile and variable available power from renewable energy sources (RESs). Among others, the Global Extremum Seeking (GES) optimization technique has shown its capability to deal with these requirements. In this paper a classical implementation of a GES controller is analyzed and an artificial neural network (ANN) based implementation is obtained, showing that the approximation is accurate.

关键词： Germanium Fuel cells Optimization Artificial neural networks Hybrid power systems Fuels control systems

Adaptive Command Filtered Backstepping control and its Application to Permanent Magnet Synchronous Generator Based Wind Energy Conversion system 1

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Adaptive Command Filtered Backstepping Control and its Appli...

1st International Conference on Sustainable Renewable Energy systems and Applications, ICSRESA 2019

作者： Soukkou, Yassine Labiod, Salim Tadjine, Mohamed Zhu, Quan Min Nibouche, Mokhtar Research Center in Industrial Technologies Crti P. O. Box. 64 Cheraga16014 Algeria Laj Faculty of Science and Technology University of Jijel BP. 98 Ouled Aissa Jijel Algeria Department of Automatic Control 10 Av. Hassen Badi Algiers Algeria University of the West of England Department of Engineering Design and Mathematics Frenchay Campus Coldharbour Lane BristolBS161QY United Kingdom University of the West of England Department of Engineering Design and Mathematics Frenchay Campus Coldharbour Lane BristolBS161QY United Kingdom

ISBN: (纸本)9781728153568

This paper introduces an adaptive command filtered backstepping control approach for lower triangular uncertain nonlinear dynamic systems. In this approach, the drawback of explosion of terms in the conventional adaptive backstepping control strategy is avoided. By using the Lyapunov stability analysis method, it is shown that all the closed-loop system signals are uniformly ultimately bounded (UUB) and the convergence of the system tracking errors to a small neighborhood of zero. The proposed adaptive filtered control strategy has been applied to a permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS) model. Numerical simulation results for the control of PMSG based WECS model are provided to highlight the performance of the adaptive command filtered based backstepping control strategy. The numerical simulations results clearly prove the efficiency of the proposed adaptive filtered control strategy. © 2019 IEEE.

关键词： Closed loop systems

automatic language identification for romance languages using stop words and diacritics: Tool/experimental paper

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arXiv 2018年

作者： Truicǎ, Ciprian-Octavian Velcin, Julien Boicea, Alexandru Computer Science and Engineering Department Faculty of Automatic Control and Computers University Politehnica of Bucharest Bucharest Romania University of Lyon ERIC Laboratory Lyon 2 Lyon France

automatic language identification is a natural language processing problem that tries to determine the natural language of a given content. In this paper we present a statistical method for automatic language identification of written text using dictionaries containing stop words and diacritics. We propose different approaches that combine the two dictionaries to accurately determine the language of textual corpora. This method was chosen because stop words and diacritics are very specific to a language, although some languages have some similar words and special characters they are not all common. The languages taken into account were romance languages because they are very similar and usually it is hard to distinguish between them from a computational point of view. We have tested our method using a Twitter corpus and a news article corpus. Both corpora consists of UTF-8 encoded text, so the diacritics could be taken into account, in the case that the text has no diacritics only the stop words are used to determine the language of the text. The experimental results show that the proposed method has an accuracy of over 90% for small texts and over 99.8% for large texts. Copyright © 2018, The Authors. All rights reserved.

关键词： Natural language processing systems

Laboratory scale wind energy harvester 9

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Laboratory scale wind energy harvester

9th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing systems: Technology and Applications, IDAACS 2017

作者： Fagarasan, Ioana Stamatescu, Iulia Nichiforov, Cristina Stamatescu, Grigore Arghira, Nicoleta Iliescu, Sergiu Stelian Faculty of Automatic Control and Computers Department of Automation and Industrial Informatics University Politehnica of Bucharest Bucharest Romania

ISBN: (纸本)9781538606971

Present and future global energy challenges assume a growing role of intelligent information technologies. Among the global objectives lay a continuous energy supply, making efficient use of energy in all its forms. Renewable energy and energy harvester systems have become a hot topic to the academia and industrial representatives, due to the last technical developments and economical support. This paper focuses on wind flow as an energy source and presents a laboratory scale wind energy harvester application suitable for powering small scale consumers. The hardware architecture is completed by a mathematical modeling of the wind energy harvester and a proposed power management system used to cover in an efficient manner the energy requirements. To prove the effectiveness of the system developments, simulations have been conducted. © 2017 IEEE.

关键词： Wind power