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International Scientific Conference on Electric Power Engineering (EPE)

作者： Miroslaw Wcislik Michal S. Laskawski Faculty of Electric Engineering Automatic Control and Computer Science Kielce University of Technology Kielce Poland

ISBN: (纸本)9781509064076

The paper deals with an analysis of features of on-off controllers. It was assumed that the control quality can be described by three distinctive indexes: the period, the amplitude and the mean value of the controlled signal in the steady state. The on-off controller with positive hysteresis was a basic form of the controller that was analyzed. To eliminate the disadvantages of this basic form the controller structure was augmented by inertia corrector. Its impact on mentioned above indicators was shown and described. To compensate the negative influence of inertia corrector on the mean value of the controlled signal, an additional proportional corrector was proposed. Its influence on control quality was shown and discussed. To show how easy it is to build the proposed structure of the controller, its exemplary implementation in the ladder logic language of the S7-1200 PLC was described.

关键词： control systems Hysteresis Steady-state Oscillators Mathematical model Software packages Computational modeling

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Chaotic behavior of new nonlinear electromagnetic microgenerator harvesting energy from mechanical vibrations

Chaotic behavior of new nonlinear electromagnetic microgener...

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International Symposium on Electrical Machines (SME)

作者： Mariusz Jagieła Marcin Kulik Faculty of Electrical Engineering Automatic Control & Computer Science Opole University of Technology Opole Poland

A low-frequency nonlinear cantilever-beam-type electromagnetic vibration energy harvester is analyzed. The nonlinearity brought into system kinematics by the “magnets-on-magnets” action provides approximately 20 Hz frequency bandwidth. A simulation study based on solution of coupled dynamic equations of motion and equation of electric balance shows that within major part of the bandwidth the system is capable to produces the voltage with magnitude proportional to magnitude and frequency of the excitation force. At very low frequency and large external forces it falls, however into region where it exhibits chaotic behavior. In this paper the impact of the phenomenon on waveform of the generated voltage is analyzed using the Poincare maps and spectrograms. The results prove a detrimental impact of the phenomenon on overall performance of the system. In order to avoid the chaotic operation the impact of the hard-stop barriers of relative displacement is analyzed showing rise of generated power and reduction of a low-frequency limit of the bandwidth.

关键词： Magnetic flux Force Magnetic resonance Magnetic hysteresis Magnetic cores Coils Magnetic circuits

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Comparative Study on Feature Selection Methods Rooted in Swarm Intelligence for Intrusion Detection

Comparative Study on Feature Selection Methods Rooted in Swa...

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International Conference on control Systems and computer science (CSCS)

作者： Adriana-Cristina Enache Valentin Sgârciu Mihai Togan Faculty of Automatic Control and Computer Science University Politehnica of Bucharest Bucharest Romania Faculty of Computer Science Military Technical Academy Bucharest Romania

ISBN: (纸本)9781538618400

Today, the cyber-space landscape is filled with vulnerabilities and malicious users that exploit them. Adding to this the technological context, with data flooding from all directions, it is evident that maintaining a good level of security for our systems has become a challenge. The high-dimensional datasets generated by all these diverse technologies needs to be processed efficiently. Inside the pool of data records gathered from all the monitored devices, there is also noise that could negatively influence intrusion detection. Feature selection methods(FSM) may offer a plausible solution to this multi-dimensionality problem, because they reduce the number of features and keep only those significant for solving the stated problem. In this paper we propose to conduct a comparative study of feature selection methods for intrusion detection. We focus on wrapper variants of FSM which are based on swarm intelligence algorithms. To conduct our study, we construct our FSM models based on four SI algorithms (PSO, BA, BAL and BAE) in combination with traditional classifiers (SVM, C4.5 and Naive Bayes) and use the NSL-KDD dataset for our test and comparative analysis.

关键词： Particle swarm optimization Support vector machines Computational modeling Feature extraction Intrusion detection Stochastic processes

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Nonasymptotic convergence of stochastic proximal point algorithms for constrained convex optimization

arXiv

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arXiv 2017年

作者： Patrascu, Andrei Necoara, Ion Computer Science Department University of Bucharest Automatic Control and Systems Engineering Department University Politehnica of Bucharest

A very popular approach for solving stochastic optimization problems is the stochastic gradient descent method (SGD). Although the SGD iteration is computationally cheap and the practical performance of this method may be satisfactory under certain circumstances, there is recent evidence of its convergence difficulties and instability for unappropriate parameters choice. To avoid these drawbacks naturally introduced by the SGD scheme, the stochastic proximal point algorithms have been recently considered in the literature. We introduce a new variant of the stochastic proximal point method (SPP) for solving stochastic convex optimization problems subject to (in)finite intersection of constraints satisfying a linear regularity type condition. For the newly introduced SPP scheme we prove new nonasymptotic convergence results. In particular, for convex and Lipschitz continuous objective functions, we prove nonasymptotic estimates for the rate of convergence in terms of the expected value function gap of order O(1/k1/2) , where k is the iteration counter. We also derive better nonasymptotic bounds for the rate of convergence in terms of expected quadratic distance from the iterates to the optimal solution for smooth strongly convex objective functions, which in the best case is of order O (1/k). Since these convergence rates can be attained by our SPP algorithm only under some natural restrictions on the stepsize, we also introduce a restarting variant of SPP method that overcomes these difficulties and derive the corresponding nonasymptotic convergence rates. Numerical evidence supports the effectiveness of our methods in real-world problems. Copyright © 2017, The Authors. All rights reserved.

关键词： Stochastic systems

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Scientific footprints in digital libraries

Scientific footprints in digital libraries

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1st International KEYSTONE Conference, IKC 2015

作者： Ifrim, Claudia Koulouri, Xenia Wallace, Manolis Pop, Florin Mocanu, Mariana Cristea, Valentin Faculty of Automatic Control and Computers Computer Science Department University Politehnica of Bucharest Bucharest060042 Romania Knowledge and Uncertainty Research Laboratory Department of Informatics and Telecommunications University of the Peloponnese Tripolis22 131 Greece

ISBN: (纸本)9783319592671

In recent years, members of the academic community have increasingly turned to digital libraries to follow the latest work within their own field and to estimate papers’, journals’ and researchers’ impact. Yet, despite the powerful indexing and searching tools available, identifying the most important works and authors in a field remains a challenging task, for which a wealth of prior information is needed;existing systems fail to identify and incorporate in their results information regarding connections between publications of different disciplines. In this paper we analyze citation lists in order to not only quantify but also understand impact, by tracing the "footprints" that authors have left, i.e. the specific areas in which they have made an impact. We use the publication medium (specific journal or conference) to identify the thematic scope of each paper and feed from existing digital libraries that index scientific activity, namely Google Scholar and DBLP. This allows us to design and develop a system, the Footprint Analyzer, that can be used to successfully identify the most prominent works and authors for each scientific field, regardless of whether their own research is limited to or even focused on the specific field. Various real life examples demonstrate the proposed concepts and actual results from the developed system’s operation prove the applicability and validity. © Springer International Publishing AG 2017.

关键词： Digital libraries

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Distributed Optimization for Second-Order Multi-Agent Systems with Dynamic Event-Triggered Communication

arXiv

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arXiv 2018年

作者： Yi, Xinlei Yao, Lisha Yang, Tao George, Jemin Johansson, Karl H. Department of Automatic Control Kth Royal Institute of Technology School of Electrical Engineering and Computer Science Stockholm100 44 Sweden Department of Electrical Engineering University of North Texas DentonTX76203 United States U.S. Army Research Laboratory AdelphiMD20783 United States

In this paper, we propose a fully distributed algorithm for second-order continuous-time multi-agent systems to solve the distributed optimization problem. The global objective function is a sum of private cost functions associated with the individual agents and the interaction between agents is described by a weighted undirected graph. We show the exponential convergence of the proposed algorithm if the underlying graph is connected, each private cost function is locally gradient-Lipschitz-continuous, and the global objective function is restricted strongly convex with respect to the global minimizer. Moreover, to reduce the overall need of communication, we then propose a dynamic event-triggered communication mechanism that is free of Zeno behavior. It is shown that the exponential convergence is achieved if the private cost functions are also globally gradient-Lipschitz-continuous. Numerical simulations are provided to illustrate the effectiveness of the theoretical results. Copyright © 2018, The Authors. All rights reserved.

关键词： Multi agent systems

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Identification of Piezomicropositioning Hammerstein Systems with Generalized Prandtl-Ishlinskii Hysteresis Nonlinearities 57

Identification of Piezomicropositioning Hammerstein Systems ...

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57th IEEE Conference on Decision and control, CDC 2018

作者： Aljanaideh, Khaled F. Janaideh, Mohammad Al Rakotondrabe, Micky Kundur, Deepa Department of Aeronautical Engineering Jordan University of Science and Technology Irbid22110 Jordan Department of Mechanical Engineering Memorial University of Newfoundland St John'sNFAlB 3X5 Canada Department of Automatic Control and Micro-Mechatronic Systems Univ. de Franche-Comt/CNRSIENSMM/UTBM FEMTO-ST Institute FEMTO-ST AS2M Univ. Bourgogne Franche-Comté Besançon France Department of Electrical and Computer Engineering University of Toronto TorontoONM5S 2E4 Canada

ISBN: (纸本)9781538613955

We introduce an algorithm to identify the nonlinear dynamics of a class of smart micropositioning systems, which is modeled as a Hammerstein system, that is, a cascade of a generalized Prandtl-Ishlinskii (GPI) hysteresis nonlinearity with a linear dynamic system. The GPI hysteresis nonlinearity, the linear dynamic system, and the intermediate signal between them are assumed to be unknown. The first stage in the algorithm is to identify the linear dynamic plant from measurements of the input and output of the Hammerstein system. Then, the unknown intermediate signal is reconstructed using the output and the identified model of the linear system. Finally, the GPI nonlinearity is estimated using the input and the reconstructed intermediate signal. © 2018 IEEE.

关键词： Hysteresis

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Conducting Online Lab Experiments with Blockly

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IFAC-PapersOnLine 2017年第1期50卷 13474-13479页

作者： Galan, Daniel Heradio, Ruben de la Torre, Luis Dormido, Sebastian Esquembre, Francisco Dept. of Computer Science and Automatic Control Universidad Nacional de Educación a Distancia Juan del Rosal 16 MadridE-28040 Spain Dept. of Software Engineering and Computer Systems Universidad Nacional de Educación a Distancia Juan del Rosal 16 MadridE-28040 Spain Dept. of Mathematics Universidad de Murcia Campus de Espinardo MurciaE-30071 Spain

Laboratory experimentation plays an essential role in control education. To reduce the high costs of maintaining apparatus in traditional labs and to support distance and blended learning, online laboratories are used as a possible alternative to conventional hands-on labs. In these labs it is often desirable to allow students to define their own experiments. This paper presents the definition and implementation of a generic experimentation language for conducting automatic experiments on existing online laboratories. The main objective is to use an online lab, created independently, as a component in which users can perform experiments. To achieve it, authors present the Experiment Application. It is composed by Blockly, to define and design the experiments, and Google Chart, review and visualize the experiment results. This tool offers benefits to students, teachers and, even, lab designers. For the moment, it can be used with any existing lab or simulation created with the authoring tool Easy Java(script) Simulations. Since there are repositories with hundreds of free available labs created with this tool, the potential applicability of the described tool is considerable. To illustrate the utility of the Experiment Application a very well-known system is used: the Simple Harmonic Oscillator system. © 2017

关键词： computer software Experiments Research laboratories Teaching Blockly Easy java(script) Simulations Experimentation Language Javascript Remote laboratories Virtual laboratories

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Design of a stabilization control system for high-speed crafts based on robust techniques. Two different approaches 11

Design of a stabilization control system for high-speed craf...

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11th IEEE Conference on Industrial Electronics and Applications, ICIEA 2016

作者： Muñoz-Mansilla, Rocío Díaz, José Manuel Chaos, Dictino Aranda, Joaquín Department of Computer Science and Automatic Control UNED Madrid Spain

ISBN: (纸本)9781509026050

This work handles the design of a stabilization control for a high-speed craft in order to improve comfort and security in maritime transport. The goal is to damp the coupled dynamics of heave, pitch and roll by using active stabilization surfaces such as flaps, T-foil and fins. The methodology used is based on the Quantitative Feedback Theory (QFT) robust technique. Two approaches depending on the degree of coupling are presented. In the first approach, controllers for the longitudinal and transversal dynamics are designed separately and afterwards the actuator coupling is considered. The second approach provides a solution in cases where the effect of the actuator coupling is large. Hence, a combination of QFT and Eigenstructure Assignment (EA) methods is used. For both methods, time-domain simulations analyses for different conditions of sea state and angles of incidence provide satisfactory results and achieve damped responses. It is shown that robust techniques based on QFT methodology result feasible and very suitable since the problem can be applied to any angle of incidence and only one controller is required for any speed or sea state. Therefore they constitute attractive alternatives in the application of a stabilization control of an advanced marine system. © 2016 IEEE.

关键词： Robust control

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Programmable Medicine: Autonomous, Ingestible, Deployable Hydrogel Patch and Plug for Stomach Ulcer Therapy

Programmable Medicine: Autonomous, Ingestible, Deployable Hy...

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IEEE International Conference on Robotics and Automation

作者： Alexis du Plessis d'Argentre Samuel Perry Yoshitaka Iwata Haruna Iwasaki Eiji Iwase Assunta Fabozzo Iain Will Daniela Rus Dana D. Damian Shuhei Miyashita Ecole Supérieure d'Electronique de l'Ouest France Department of Electronic Engineering University of York York UK Department of Applied Mechanics Waseda University Japan Hospital of Padua Italy Computer Science and Artificial Intelligence Laboratory MIT USA Department of Automatic Control and System Engineering University of Sheffield UK

Gastric ulcer is a chronic and complex (and often complete) erosion of the stomach wall that happens as a complication of a previous chronic, inflammatory process. It represents a catastrophic situation in which the patient is critical and its conditions need to be treated fast. This study presents a remotely navigatable and deployable ingestible patch and plug for gastric ulcer treatment. The patch/plug structure is made of agarose hydrogel that can change rigidity through hydration and dehydration. When dehydrated, it is rigid and can maintain a folded configuration so it can be ingested as a "pill". This can be guided to the targeted location by a magnetic field, and be deployed instantly by hydration, namely by supplying water from the mouth. Due to the deployable origami design, it exhibits an expansion of 10 times its initial surface area, making the device suitable for the use of dressing a surface as a patch, and filling a hole as a plug.

关键词： Plugs Stomach Navigation Shape Fabrication Robot sensing systems

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