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International Scientific Conference on Electric Power Engineering (EPE)

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

ISBN: (纸本)9781509064076

The paper deals with the PI and PID controllers settings. The research includes an overview of the most commonly used control quality criteria. It was assumed that the controlled system can be approximated by first order inertia with dead time. The control systems that includes the model as well as the PI and PID controllers were analyzed in context of control quality taking into account ITAE criterion. The research involved an analysis of the Nyquist diagrams. It enabled us to formulate a new method of tuning of PI and PID controllers. The results obtained with the proposed method were compared to the settings obtained with Ziegler-Nichols method. To illustrate the advantages of the proposed method the system step responses as well as their time and frequency indexes were compared and presented. The proposed method of the PI and PID controller tuning makes it possible to obtain a significant increase of the control quality.

关键词： control systems Mathematical model Tuning Stability criteria Oscillators Steady-state

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Effects of complex motion in a new cantilever-beam nonlinear electromagnetic vibration energy harvester 18

Effects of complex motion in a new cantilever-beam nonlinear...

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18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering, ISEF 2017

作者： Jagiela, Mariusz Kulik, Marcin Faculty of Electrical Engineering Automatic Control and Computer Science Opole University of Technology Opole Poland

ISBN: (纸本)9781538616611

A new cantilever-beam nonlinear electromagnetic vibration energy harvester with noticeable effects of complex motion composed of relative displacement and torsion of the vibrating element is considered. The analysis of frequency characteristics carried out using the finite element models shows significant differences regarding generated output voltage and frequency bandwidth when detailed 2-d variations of the magnetic force components are taken into account. © 2017 IEEE.

关键词： Energy harvesting

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Relationship between resistance, TCR and stabilization temperature of amorphous Ni-P alloy

Relationship between resistance, TCR and stabilization tempe...

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作者： Filipowski, Wojciech Pruszowski, Zbigniew Waczynski, Krzysztof Kowalik, Piotr Kulawik, Jan Faculty of Automatic Control Electronics and Computer Science Silesian University of Technology Gliwice Poland Institute of Electronics Silesian University of Technology Gliwice Poland Kraków Division Institute of Electron Technology Kraków Poland

Purpose - The paper aims to present a research on the impact of the stabilization process of a thin metallic layer (Ni-P) produced on a ceramic surface (Al2O3) by means of electroless metallization on its electric parameters and structure. On the basis of the research conducted, the existence of a relationship between resistance (R) and the temperature coefficient of resistance (TCR) of the test structure with a Ni-P alloy-based layer and the temperature of stabilization was proposed. Design/methodology/approach - Metallic Ni-P layers were deposited on sensitized and activated substrates. Metallization was conducted in an aqueous solution containing two primary ingredients: Sodium hypophosphite and nickel chloride. The concentration of both ingredients was (50-70) g/dm3. The process lasted 60 min, and the metallization bath pH was kept at 2.1-2.2, whereas the temperature was maintained at 363 K. The thermal stabilization process was conducted in different temperatures between 453 and 623 K. After the technological processes, the resistance and TCR of the test structures were measured with a micro ohmmeter. The composition and the morphology of the resistive layer of the structures examined was also determined. Findings - The dependence of the resistance on the temperature of the stabilization process for the temperature range 553 to 623 K was described using mathematical relationships. The TCR of test resistors at the same thermal stabilization temperature range was also described using a mathematical equation. The measurements show that the resistive layer contains 82.01 at.% of nickel (Ni) and 17.99 at.% of phosphorus (P). Originality/value - The results associate a surface morphology Ni-P alloy with the resistance and TCR according to temperature stabilization. The paper presents mathematical relationships that have not been described in the literature available. © 2017 Emerald Publishing Limited.

关键词： Temperature

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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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Correction of the on-off control system using PLC

Correction of the on-off control system using PLC

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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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Two practical random-subcarrier-selection methods for secure precise wireless transmission

arXiv

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arXiv 2018年

作者： Shen, Tong Zhang, Shuo Chen, Riqing Wang, Jin Hu, Jinsong Shu, Feng Wang, Jiangzhou School of Electronic and Optical Engineering Nanjing University of Science and Technology 210094 China School of Computer and information Fujian Agriculture and Forestry University Fuzhou350002 China National Key Laboratory of Science and Technology on Aerospace Intelligence Control Beijing Aerospace Automatic Control Institute Beijing100854 China School of Engineering and Digital Arts University of Kent CanterburyCT2 7NT United Kingdom

In directional modulation (DM) networks, two practical random-subcarrier-selection (RSS) methods are proposed to transmit confidential message to the desired user per orthogonal frequency division multiplexing (OFDM) symbol with only single receive power peak formed by constructing random subcarrier set and performing a randomization procedure. This scheme completely addresses the crucial problem facing secure precise wireless transmission (SPWT), how to achieve the SPWT per OFDM symbol while the traditional SPWT holds only in the statistically average sense. Several necessary conditions for SPWT per OFDM is derived and proposed: random, distributed, and distinct subcarrier spacing pattern mapped onto transmit antenna array. Two random subcarrier index sets, quadratic subcarrier set (QSS) and prime subcarrier set (PSS), are constructed. Subsequently, a random metric is defined, and a randomization procedure (RP) is proposed. Its detailed process includes the following steps: integer mod, ordering, blocking, and block interleaving (BI) where BI is repeated until the random metric is greater than the predefined value. This yields a single high energy main peak (SHEMP) at the desired position with other positions, outside the main peak, harvesting only weak receive energy seriously corrupted by AN. Simulation results confirm that our proposed two methods, QSS plus RP and PSS plus RP, perform significantly better than conventional methods such as linear subcarrier set (LSS) plus RP. They actually form a SHEMP at desired position, and generate only extremely small leakage outside the main peak. Copyright © 2018, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

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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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