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2011 IEEE International Symposium on Applications of Ferroelectrics(ISAF/PFM 2011) and 2011 International Symposium on Piezoresponse Force Microscopy and Nanoscale Phenomena in Polar Materials

作者： K. Novakova P. Mokry Institute of Mechatronics and Computer Engineering Technical University of Liberec Studentska 2 Liberec I CZ-46117 Czech Republic

ISBN: (纸本)9781457711626

An investigation on the application of the piezoelectric Macro-Fiber-Composite (MFC) actuators for the suppression of the noise transmission through the curved glass plates is presented. It is known that when the incident sound wave in the air hits the glass plate or curved plate or shell, part of the acoustic wave is reflected, which makes the plate vibrate, and part of the wave is transmitted. It is easy to understand that the higher the flexural rigidity of the glass plate the bigger part of the acoustic sound wave is reflected than transmitted. This simple physical phenomenon can be profitably used for the suppression of the noise transmission through glass plates. The noise suppression effect is achieved using the MFC actuator, which is attached to the vibrating glass plate. When the piezoelectric MFC actuator is shunted by the active electronic circuit, which has a negative capacitance, it is possible to greatly suppress the vibration of the glass plate and also the noise transmission through the glass plate. The sound shielding efficiency of the glass plate is measured by the acoustic transmission loss (TL), which is expresed in decibel scale. If the amplitude of the window vibrations decreases, the value of TL increases. The effect of the glass plate geometry, and the electrical properties of the active shunt circuit on the enhancement of TL is analyzed using Finite Element Method numerical simulations. The comparison of the results of numerical simulations with acoustic measurements is presented. The possibility of the use of this method for the suppression of the noise transmission through the glass window plates is discussed.

关键词： Glass window MFC piezoelectric actuator Noise Transmission FEM Simulation

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Extreme dynamics on eCAM linear drive

Extreme dynamics on eCAM linear drive

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14th International Power Electronics and Motion Control Conference, EPE-PEMC 2010

作者： Černohorský, J. Technical University of Liberec Institute of Mechatronics and Computer Engineering Liberec Czech Republic

The aim of this paper is a description of using linear drive for cyclic traversal motion. The maximum acceleration is up to 22G, the frequency of motion is 3.2 Hz. Therefore the linear motor is controlled by electroni... 详细信息

ISBN: (纸本)9781424478545

关键词： Linear motors

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A system for the vibration suppression in the broad frequency range using a single piezoelectric actuator shunted by a negative capacitor

A system for the vibration suppression in the broad frequenc...

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IEEE International Symposium on Applications of Ferroelectrics (ISAF)

作者： M. Kodejška J. Václavík P. Mokrý Institute of Mechatronics and Computer Engineering Technical University of Liberec Liberec Czech Republic

A system for the vibration suppression using a single piezoelectric actuator is presented. The method is based on the fact that the transmission of vibrations between two objects can be reduced through an extremely soft element, which is placed between those objects. It is also known that by connecting a negative capacitor to the piezoelectric actuator it is possible to create an element whose elasticity can be arbitrarily tuned. Therefore, by combining these two principles, a new vibration control system, which consists of a piezoelectric actuator connected to a negative capacitor, has been realized. High efficiency of the vibration transmission suppression is achieved when the amplitude and phase of the piezoelectric actuator impedance matches (except the sign) the amplitude and phase of the negative capacitor impedance. The frequency, at which the both dependencies are intersecting, can be controlled by adjustable circuit elements of the negative capacitor. Every single setting of the negative capacitor parameters is optimal just for one corresponding frequency of the incident vibrations. In the case of vibration suppression in a broader frequency range, the frequency dependence of the negative capacitor capacitance has to match the frequency dependence of the piezoelectric element capacitance within the entire considered frequency range. By one single optimal setting of the negative capacitor parameters can be efficiently suppressed the transmission of vibrations with several harmonic components or with a random component. Two difficulties have been solved in the presented realization: first, the electronic arrangement that allows the extremely accurate adjustment of the negative capacitor circuit parameters and, second, the principle which allows achieving exactly the desired frequency impedance characteristics of the negative capacitor. It is shown that such an arrangement allows the realization of a simple and compact system, which, however, offers great vibr

关键词： Vibrations Capacitors Piezoelectric actuators Capacitance Impedance Frequency dependence White noise

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Extreme dynamics on eCAM linear drive

Extreme dynamics on eCAM linear drive

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International (EPE-PEMC) Power Electronics and Motion Control Conference

作者： M. Se. J. Černohorský Technical University of Liberec Institute of Mechatronics and Computer engineering Liberec Czech Republic

关键词： computer aided manufacturing Acceleration Synchronization Motion control Torque Harmonic analysis Couplings

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Analysis of noise transmission through the window glass plate and its control using the Macro Fiber Composite actuator

Analysis of noise transmission through the window glass plat...

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IEEE International Symposium on Applications of Ferroelectrics (ISAF)

作者： K. Nováková P. Mokrý J. Václavik V. Lédl Institute of Mechatronics and Computer Engineering Technical University of Liberec Studentska 2 Liberec I Czech Republic

Glass windows are integral parts of buildings for several centuries. Unfortunately, they represent a major source of the interior noise, since they usually do not represent an effective sound barrier due to their low flexural rigidity. The aim of this work is to understand the sound transmission through the glass window and to analyze and demonstrate a new approach to reduce the noise transmission through the glass plate using a Macro Fiber Composite (MFC) piezoelectric actuator. The principle of Active Piezoelectric Shunt Damping (APSD) is used to achieve the required suppression of the noise transmission.. The system is modeled by Finite Element Method (FEM) numerical simulations. The results are experimentally verified using Digital Holographic Interferometry (DHI).

关键词： Glass Acoustics Windows Noise Computational modeling Actuators Finite element methods

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Piecewise affine approximation of nonlinear systems - A case study of a benchmark nonlinear boiler

Piecewise affine approximation of nonlinear systems - A case...

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作者： Horálek, Radek Hlava, Jaroslav Institute of Systems Control and Reliability Management Technical University of Liberec Faculty of Mechatronics 416 17 Liberec Czech Republic Institute of Mechatronics and Computer Engineering Technical University of Liberec Faculty of Mechatronics Studentská 2 416 17 Liberec Czech Republic

ISBN: (纸本)9789604741311

This paper deals with piecewise affine (PWA) approximation of nonlinear systems. Its motivation is simple. If the controlled plant exhibits nonlinear behavior, linear controller based on linearized model may often be unable to achieve satisfactory performance. On the other hand, intrinsic complexity of the nonlinear controller based on full nonlinear model may prevent it from practical application. PWA model that uses a set of switched partial linear models can then represent the middle way between simplifications of the linearized model and complexity of the nonlinear model. The paper uses a case study of a nonlinear power plant boiler. It shows that its complex nonlinear dynamical behavior can well be approximated with a relatively simple PWA system. Unlike one linearized model, this PWA approximation fits boiler dynamic behavior very well. As the development of model predictive control of the PWA systems has already reached a substantial level of maturity, this PWA model can be used as a basis for the design of hybrid model predictive control for this boiler.

关键词： Hybrid systems

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Evidence for dielectric aging due to progressive 180° domain wall pinning in polydomain Pb(Zr0.45Ti0.55)O3 thin films

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Physical Review B 2009年第5期79卷 054104-054104页

作者： Pavel Mokrý Yongli Wang Alexander K. Tagantsev Dragan Damjanovic Igor Stolichnov Nava Setter Institute of Mechatronics and Computer Engineering Technical University of Liberec CZ-46117 Liberec Czech Republic Department of Materials Ceramics Laboratory EPFL Swiss Federal Institute of Technology CH-1015 Lausanne Switzerland

An evidence that the dielectric aging in the polydomain Pb(Zr0.45Ti0.55)O3 thin films is controlled by progressive pinning of 180° domain walls is presented. To provide such a conclusion, we use a general method, which is based on the study of the time evolution of the nonlinear but anhysteretic dielectric response of the ferroelectric to a weak electric field. A thermodynamic model of the ferroelectric system where the dielectric response is controlled by bending movements of pinned 180° domain walls is developed. Within this model, the nonlinear permittivity of the ferroelectric is expressed as a function of the microstructural parameters of the domain pattern. It is shown that by using the analysis of the time evolution of the nonlinear permittivity, it is possible to estimate changes in the concentration of the pinning centers that block the movements of the 180° domain walls during aging in polydomain perovskite ferroelectrics.

关键词： ageing electric domains ferroelectric thin films lead compounds permittivity

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Parallel algorithm for query content based webpages ranking

Lecture Notes in Business Information Processing

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Lecture Notes in Business Information Processing 2009年 21 LNBIP卷 85-96页

作者： Vraný, Jirí Institute of New Technologies and Applied Informatics Faculty of Mechatronics and Interdisciplinary Engineering Studies Technical University of Liberec Czech Republic

ISBN: (纸本)9783642011894

The Intelligent Surfer is one of algorithms designed for ranking of search engine results. It is an interesting combination of the PageRank algorithm and the content of web pages. Its main disadvantage is long computation time compared to the PageRank computation time. A computation of the PageRank itself is a very time-consuming process. A lot of papers with topic of efficiency and speed-up of the PageRank computation were published. This paper brings a proposal of speed-up of the Intelligent Surfer algorithm in three steps denoted as the CZDIS algorithm. Experiments with web graph of 1 million nodes size proved that proposed algorithm is usable solution for search engine results ranking in dependance on the page content. Successful implementation of Czech language model experimentally proved possibility of Intelligent Surfer application to different, non English languages. © 2009 Springer Berlin Heidelberg.

关键词： Search engines

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COMP - Comparing Ontology Matching Plug-in

COMP - Comparing Ontology Matching Plug-in

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International Conference on Next Generation Web Services Practices (NWeSP)

作者： Pavel Tyl Jan Loufek Institute of Computer Science Academy of Sciences슠of the슠Czech Republic Prague Czech Republic Faculty of Mechatronics Technical University of Liberec Liberec Czech Republic

Improving the ontology integration seems to be an important thing for maintenance of cooperation among various directions of ontology engineering (semantic web services, social networks, etc.). While particular ontologies cover a view at one specific domain of interest, many applications require much more general approach to describe their data. On this account it approaches to a promising solution to the semantic heterogeneity, ontology matching. Matching can be improved in various ways, such as improving matching strategies, tools and systems, basic techniques and methods or by explaining, representing and further processing and evaluating matching results. This paper describe a matching plug-in into the open-source ontology editor, Prote¿ge¿. The plug-in is called COMP and it is a tool for comparing and evaluating various matching techniques and strategies.

关键词： Ontologies Semantic Web Social network services Open source software Next generation networking Web services computer science mechatronics Knowledge acquisition Concrete

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Photopolymer for Optical Holography and Holographic Interferometry

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Macromolecular Symposia 2010年第1期295卷

作者： M. Květoň V. Lédl A. Havránek P. Fiala Czech Technical University in Prague Faculty of Nuclear Sciences and Physical Engineering Department of Physical Electronics Břehová 7 115 19 Prague 1 Czech Republic Technical University of Liberec Faculty of Mechatronics Informatics and Interdisciplinary Studies Studentská 2 Liberec Czech Republic Institute of Plasma Physics AS CR v.v.i. Za Slovankou 3 182 00 Prague 8 Czech Republic Charles University Faculty of Mathematics and Physics Department of Macromolecular Physics V Holešovičkách 2 180 00 Prague 8 Czech Republic

Summary: In our laboratory, we have continued in experimental study of acrylamide-based photopolymer recording material. Our exposition and detection setup was used for real-time measurements of a diffraction grating formation process. Based on the results of our measurements, the chemical composition of the material was modified to increase sensitivity, value of refractive index modulation and stability of the formed structure. Recently, the material has been successfully applied to holographic interferometry.

关键词： holographic interferometry holography photopolymerization recording material refractive index

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