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8th European Conference on Noise control 2009, EURONOISE 2009

作者： Štimac, Igor Jakšić, Zoran Bucak, Tino Novak, Doris Jambrošić, Kristian Zagreb Airport Ltd. Pleso bb. 10000 Zagreb Croatia Croatia Control Ltd. Pleso bb. 10000 Zagreb Croatia Faculty of Transport and Traffic Sciences Vukelićeva 4 10000 Zagreb Croatia Faculty of Electrical Engineering and Computing Unska 3 10000 Zagreb Croatia

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Intensity inhomogeneity correction and segmentation of magnetic resonance images using a multi-stage fuzzy clustering approach

Intensity inhomogeneity correction and segmentation of magne...

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作者： Szilágyi, Sándor M. Szilágyi, László Iclanzan, David Ddvid, László Frigy, Attila Benyó, Zoltán Sapientia University of Transylvania Faculty of Technical and Human Sciences Tirgu Mures Romania Babes-Bolyai University Faculty of Mathematics and Computer Science Cluj-Napoca Romania Medical Clinic No. 4 Tirgu Mures Romania Budapest University of Technology and Economics Department of Control Engineering and Information Technology Hungary

Intensity inhomogeneity or intensity non-uniformity (INU) is an undesired phenomenon that represents the main obstacle for magnetic resonance (MR) image segmentation and registration methods. Various techniques have been proposed to eliminate or compensate the INU, most of which are embedded into clustering algorithms, and they generally have difficulties when INU reaches high amplitudes. This study proposes a multiple stage fuzzy c-means (FCM) clustering based algorithm for the estimation and compensation of INU, by modelling it as a slowly varying additive or multiplicative noise. The slowly varying behaviour of the bias or gain field is assured by a smoothing filter that performs a context dependent averaging, controlled by a morphological criterion. The segmentation is also supported by a prefiltering technique for Gaussian and impulse noise elimination. The experiments using 2-D synthetic phantoms and real MR images indicate that the proposed method provides accurate segmentation. The resulting segmentation and fuzzy membership values can serve as excellent support for 3-D registration and surface reconstruction techniques. © ICS AS CR 2009.

关键词： Magnetic resonance

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LMI based design for the Acrobot walking 9th

LMI based design for the Acrobot walking

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9th IFAC Symposium on Robot control, SYROCO 2009

作者： Anderle, Milan Čelikovský, Sergej Henrion, Didier Zikmund, Jirǎí Czech Technical University in Prague Faculty of Electrical Engineering Department of Control Engineering Technická 2 Prague166 27 Czech Republic Institute of Information Theory and Automation Academy of Sciences of the Czech Republic Pod vodárenskou věží 4 Prague182 08 Czech Republic LAAS-CNRS University of Toulouse 7 avenue du colonel Roche Toulouse31077 France

ISBN: (纸本)9781617825583

This paper aims to further improve previously developed design for Acrobot walking based on partial exact feedback linearization of order 3. Namely, such an exact system transformation leads to an almost linear system where error dynamics along trajectory to be tracked is a 4-dimensional linear time-varying system having 3 time-varying entries only, the remaining entries being either zero or one. In such a way, exponentially stable tracking can be obtained by quadratically stabilizing a linear system with polytopic uncertainty. The current improvement is based on applying LMI methods to solve this problem numerically. This careful analysis significantly improves previously known approaches. Numerical simulations of Acrobot walking based on the above mentioned LMI design are demonstrated as well.

关键词： Linear matrix inequalities

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Application of Hybrid c-Means Clustering Models in Inhomogeneity Compensation and MR Brain Image Segmentation

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IFAC Proceedings Volumes 2009年第12期42卷 204-209页

作者： László Szilágyi Sándor M. Szilágyi Balázs Benyó Zoltán Benyó Faculty of Technical and Human Sciences Sapientia – Hungarian Science University of Târgu-Mureş Romania (Tel: +40-747-352560 Department of Control Engineering and Information Technology Budapest University of Technology and Economics Budapest Hungary

Intensity inhomogeneity or intensity non-uniformity (INU) is an undesired phenomenon that represents the main obstacle for MR image segmentation and registration methods. Various techniques have been proposed to eliminate or compensate the INU, most of which are embedded into clustering algorithms. This paper proposes a hybrid c-means clustering approach to replace the FCM algorithm found in several existing solutions. The novel clustering model is assisted by a pre-filtering technique for Gaussian and impulse noise elimination, and a smoothening filter that helps the c-means algorithm at the estimation of inhomogeneity as a slowly varying additive or multiplicative noise. The slow variance of the estimated INU is assured by a smoothening filter that performs a context dependent averaging, based on a morphological criterion. The experiments using 2-D synthetic phantoms and real MR images show that the proposed method provides more accurate and more efficient segmentation than the FCM based approach. The produced segmentation and fuzzy membership values can serve as excellent support for 3-D registration and segmentation techniques.

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Anti-synchronization chaos shift keying method: error derivative detection improvement. *

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IFAC Proceedings Volumes 2009年第7期42卷 128-133页

作者： Sergej Ĉelikovský Volodymyr Lynnyk Institute of Information Theory and Automation Academy of Sciences of the Czech Republic P.O. Box 18 182 08 Prague 8 Czech Republic Department of Control Engineering Faculty of Electrical Engineering Czech Technical University in Prague Czech Republic

This paper studies a new modification of the anti-synchronization chaos shift keying scheme for the secure encryption and decryption of data. A new concept of the detection of the correct/incorect binary value in the receiver is used. The method proposed here requires very reasonable amount of data to encrypt and time to decrypt a single bit. Basically, to encrypt a single bit, only one iteration is needed. Moreover, the security of this method is systematically investigated showing its good resistance to typical decryption attacks. Theoretical results are supported by the numerical simulations.

关键词： Nonlinear system chaos shift keying generalized Lorenz system synchronization anti-synchronization secure communication

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Efficient chaos shift keying method based on the second error derivative anti-synchronization detection

Efficient chaos shift keying method based on the second erro...

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International Conference on control and Automation (ICCA)

作者： Sergej Čelikovský Volodymyr Lynnyk Institute of Information Theory and Automation Academy of Sciences슠of the슠Czech Republic Prague Czech Republic Department of Control Engineering Faculty of Electrical Engineering Czech Technical University Czech Republic

This paper studies yet another improvement of the anti-synchronization chaos shift keying scheme for the secure encryption and decryption of the digital data. A new concept of the detection of the correct binary value in the receiver is introduced here. The proposed method requires very reasonable amount of data to encrypt and time to decrypt one bit. Basically, to encrypt one bit, only one iteration (i.e. only one real number of 6 valid digits) is needed. At the same time, thanks to the anti-synchronization detection based on the synchronization error second derivative, almost 100% of the carrying chaotic signal can be used. The security of the proposed method can be systematically investigated showing its good resistance against typical decryption attacks. The theoretical analysis of the introduced method is supported by the numerical experiments with digital data encryption.

关键词： Chaos Cryptography Automation Frequency synchronization Data security Automatic control Error correction Signal analysis control engineering System testing

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A weighted patient specific electromechanical model of the heart

A weighted patient specific electromechanical model of the h...

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International Symposium on Applied Computational Intelligence and Informatics ( SACI)

作者： Sandor M. Szilagyi Laszlo Szilagyi David Iclanzan Zoltan Benyo Faculty of Technical and Human Sciences Sapientia Hungarian Science University of Targu Mures Romania Faculty of Technical and Human Sciences Sapientia Hungarian Science University of Târgu Mureş Romania Faculty of Computer Science Babes Bolyai University Romania Department of Control Engineering and Information Technology Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

This paper presents a patient specific deformable heart model that involves the known electric and mechanic properties of the cardiac cells and tissue. The accuracy and efficiency of the algorithm was tested for anisotropic and inhomogeneous 3D domains using ten Tusscher's and Nygen's cardiac cell models. During propagation of depolarization wave, the kinetic, compositional and rotational anisotropy is included in the tissue, organ and torso model. The applied patient specific parameters were determined by an evolutionary computation method. An intensive parameter reduction was performed using the abstract formulation of the searching space. This patient specific parameter representation enables the adjustment of deformable model parameters in real-time. The validation process was performed using measured ECG and ultrasound image records that were compared with simulated signals and shapes using an abstract, parameterized evaluation criterion.

关键词： Heart Deformable models Anisotropic magnetoresistance Shape measurement Mechanical factors Testing Kinetic theory Torso Evolutionary computation Performance evaluation

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Experimental verification and comparison of mode shape-based damage detection methods

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Key engineering Materials 2009年 413-414卷 699-706页

作者： Radzieñski, Maciej Krawczuk, Marek Ostachowicz, Wieslaw Technical University of Gdansk Faculty of Electrical and Control Engineering Narutowicza 11/12 80-952 Gdansk Poland Institute of Fluid Flow Machinery Polish Academy of Sciences ul. Fiszera 14 80-952 Gdansk Poland

Abstract: This paper presents experimental verification and comparison of damage detection methods based on changes in mode shapes such as: mode shape curvature (MSC), modal assurance criterion (MAC), strain energy (SE), modified Laplacian operator (MLO), generalized fractal dimension (GFD) and Wavelets Transform (WT). The object of the investigation is to determine benefits and drawbacks of the aforementioned methods and to develop data preprocessing algorithms for increasing damage assessment effectiveness by using signal processing techniques such as interpolation and extrapolation measured points. Noise reduction algorithms based on moving average, median filter and wavelet decomposition are also tested. The experiments were performed on a 1m long steal cantilever beam. Damage was introduced in form of 10% and 20% deep saw cut, placed in 10%, 30%, 50%, 70% and 90% beam length. Measurements were made using non-contact Scanning Laser Doppler Vibrometer at 125 points equally spaced along beam length.

关键词： Median filters

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Application of hybrid c-means clustering models in inhomogeneity compensation and MR brain image segmentation

Application of hybrid c-means clustering models in inhomogen...

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International Symposium on Applied Computational Intelligence and Informatics ( SACI)

作者： Laszlo Szilagyi Sandor M. Szilagyi Balazs Benyo Zoltan Benyo Faculty of Technical and Human Sciences Sapientia Hungarian Science University of Târgu Mureş Romania Department of Control Engineering and Information Technology Budapest University슠of슠Technology슠and슠Economics Budapest Hungary

Intensity inhomogeneity or intensity non-uniformity (INU) is an undesired phenomenon that represents the main obstacle for MR image segmentation and registration methods. Various techniques have been proposed to eliminate or compensate the INU, most of which are embedded into clustering algorithms. This paper proposes a hybrid C-means clustering approach to replace the FCM algorithm found in several existing solutions. The novel clustering model is assisted by a pre-filtering technique for Gaussian and impulse noise elimination, and a smoothening filter that helps the C-means algorithm at the estimation of inhomogeneity as a slowly varying additive or multiplicative noise. The slow variance of the estimated INU is assured by a smoothening filter that performs a context dependent averaging, based on a morphological criterion. The experiments using 2-D synthetic phantoms and real MR images show that the proposed method provides more accurate and more efficient segmentation than the FCM based approach. The produced segmentation and fuzzy membership values can serve as excellent support for 3-D registration and segmentation techniques.

关键词： Brain modeling Image segmentation Clustering algorithms Magnetic resonance imaging Gaussian noise Filters Additive noise Imaging phantoms Filtering Iterative algorithms

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Discrete time minimax tracking control with disturbance estimation

Discrete time minimax tracking control with disturbance esti...

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European control Conference (ECC)

作者： Péter Bauer Balázs Kulcsár József Bokor Faculty of Mechanical Maritime and Materials Engineering Technical University of Delft Delft Nederland Systems and Control Laboratory Hungarian Academy of Sciences Budapest Hungary Magyar Tudomanyos Akademia Szamitastechnikai es Automatizalasi Kutatointezet Budapest Budapest HU

The paper proposes an alternative way to solve robust reference tracking problem. Instead of rejecting the effect of the disturbance directly, an intermediate step is built into the state estimation problem. The advantage of the methodology is to elaborate a modified optimal state estimation problem taking the unbiased estimate of the disturbance into account. Henceforward, the solution of the discrete time, optimal LQ minimax tracking problem is modified and subjected to attenuate the disturbance residual. The paper addresses the nominal case for constant reference and disturbance signal showing the asymptotical stability and the tracking performance of the discrete time, optimal min-max control. Suboptimal solution is given for time varying reference and disturbance signal. A linearized hovering quadrotor example demonstrates the importance of the suggested technique.

关键词： Equations Steady-state Mathematical model Estimation control systems Transient analysis Europe

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