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Transmission and reflection coefficients for damage identification in 1D elements

Key engineering Materials 2009年 413-414卷 95-100页

作者： Krawczuk, Marek Palacz, Magdalena Zak, Arkadiusz Ostachowicz, Wieslaw Technical University of Gdansk Faculty of Electrical and Control Engineering Narutowicza 11/12 80-952 Gdansk Poland Polish Academy of Sciences 14 Fiszera Street 80-952 Gdansk Poland Gdynia Maritime University Faculty of Navigation Al. Zjednoczenia 3 81-345 Gdynia Poland

According to the latest research results presented in the literature changes in propagating waves are one of the most promising parameters for damage identification algorithms. Numerous publications describe methods of damage identification based on the analysis of signals reflected from damage. They also include complicated signal processing techniques. Such methods work well for damage localisation, but it is rather difficult to use them in order to estimate the size of damage. It is natural that propagating wave reflects from any structural discontinuity. The bigger the disturbance the bigger part of a propagating wave reflects from it. The amount of energy reflected and transmitted through any discontinuity can expressed as reflection and transmission coefficients. In the literature different application for these coefficients may be found - the most often cited application is connected with localising changes in the geometry of structures. Changes in the coefficients due to cross section variations in rods and beams or due to existence of stiffeners in plates are well documented. However there are no application of using the reflection and transmission coefficients for damage size identification. For this reason the analysis presented in this paper has been carried out. The article presents a method of damage identification in 1D elements based on the wave propagation phenomenon and changes in reflection and transmission coefficients. The changes in transmission and reflection coefficients for waves propagating in isotropic rods with different types of damage have been analysed. The rods have been modelled with the elementary, two and three mode theories or rods. For numerical modelling the Spectral Finite Element Method has been used. Several examples are given in the paper.

关键词： Wave propagation

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Influence of alcohol on reliability and safety driver during driving on vehicle simulators

Influence of alcohol on reliability and safety driver during...

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作者： Piekník, Roman Department of Control Engineering and Telematics Czech Technical University Prague Faculty of Transportation Sciences Konviktská 20 110 00 Prague Czech Republic

ISBN: (纸本)9789604741359

Alcohol, drugs and consequent serious attention decrease and aggression of human operators is one of the most common causes of accidents in traffic. Measure this situations are very dangerous and in real traffic. The paper describes objective methods used for detection of driving impairment caused by influence of different level of alcohol in blood. It describes proposed methodology of measurements and data analysis. It covers also the issues of testing track creation and measurement procedure protocol. Finally the results of data analysis and proposals for further utilization of these tools and methods are presented.

关键词： Virtual reality

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Experimental verification of damage detection methods based on mode shape measurements for beams and plates.

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PAMM 2010年第1期9卷

作者： Maciej Radzieński Marek Krawczuk 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

This paper presents experimental verification and comparison of damage detection methods based on changes in mode shapes such as: mode shape curvature (MSC), damage index (DI), 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 of measured points. Noise reduction algorithms are also tested. The experiments were performed on a steel cantilever beam and on an aluminium plate with riveted stiffeners. Damage was introduced in a form of open crack for beam object and damaged rivets and a saw cut in the angle bar for plate structure. Measurements were made using non-contact Scanning Laser Doppler Vibrometer (SLDV) at 125 points along beam length and 101 points in two rows, distributed on over the plate height and positioned along two reinforcing ribs. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

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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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作者： Szilágyi, László Szilágyi, Sándor M. Benyó, Balázs Benyó, Zoltán Faculty of Technical and Human Sciences Sapientia - Hungarian Science University of TǍrgu-Mureş Romania Department of Control Engineering and Information Technology Budapest University of Technology and Economics Budapest Hungary

ISBN: (纸本)9783902661494

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. © 2009 IFAC.

关键词： Clustering algorithms

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Discrete time minimax tracking control with disturbance estimation 10

Discrete time minimax tracking control with disturbance esti...

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2009 10th European control Conference, ECC 2009

作者： Bauer, Peter Kulcsar, Balazs Bokor, Jozsef Systems and Control Laboratory Computer and Automation Research Institute Hungarian Academy of Sciences BudapestH-1111 Hungary Delft Center for System and Control Faculty of Mechanical Maritime and Materials Engineering Technical University of Delft Mekelweg 2 Delft Netherlands

ISBN: (纸本)9783952417393

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. © 2009 EUCA.

关键词： State estimation

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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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2009 5th International Symposium on Applied Computational Intelligence and Informatics, SACI 2009

作者： Szilágyi, Sándor M. Szilágyi, László Iclanzan, David Benyó, Zoltán Faculty of Technical and Human Sciences Sapientia - Hungarian Science University of Târgu Mures Romania Faculty of Computer Science Babes-Bolyai University of Cluj Napoca Romania Department of Control Engineering and Information Technology Budapest University of Technology and Economics Budapest Hungary

ISBN: (纸本)9781424444786

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. ©2009 IEEE.

关键词： Heart

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Anti-synchronization chaos shift keying method: Error derivative detection improvement

Anti-synchronization chaos shift keying method: Error deriva...

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作者： Čelikovský, Sergej Lynnyk, Volodymyr 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 Prague Czech Republic

ISBN: (纸本)9783902661654

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： Synchronization

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Quality assessment of digital television picture based on local feature matching

Quality assessment of digital television picture based on lo...

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International Conference on Digital Signal Processing (DSP)

作者： Dusica Marijan Vladimir Zlokolica Nikola Teslic Vukota Pekovic Faculty of Technical Sciences Computing and Control Department University of Novi Sad Novi Sad Serbia Micronas NIT Novi Sad Serbia

This paper presents a novel, full-reference image quality measurement method for video quality assessment in television systems. Particularly, the proposed metric targets the problem of automatic assessment of digital picture degradations. The performance of proposed algorithm has been evaluated on different image sequences with various distortions of interest. The results show that the proposed scheme for quality assessment outperforms other image quality measures: PSNR, SSIM and VIF in terms of more efficient quality inspection based on local feature matching as well as robustness against various distortions such as luminance or contrast change, negligible picture misalignment, etc.

关键词： Quality assessment Digital TV Image quality Distortion measurement PSNR Fault detection Degradation Signal processing Brightness Inspection

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On the identification of LPV traffic flow model 10

On the identification of LPV traffic flow model

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2009 10th European control Conference, ECC 2009

作者： Luspay, T. Kulcsar, B. Van Wingerden, J.W. Verhaegen, M. Systems and Control Laboratory Computer and Automation Research Institute Hungarian Academy of Sciences Kende u. 13.-17 BudapestH-1111 Hungary Delft Center for System and Control Faculty of Mechanical Maritime and Materials Engineering Technical University of Delft Mekelweg 2 Delft Netherlands

ISBN: (纸本)9783952417393

关键词： LPV Identification Linear Parameter Varying (LPV) systems freeway traffic modeling Traffic flow Authentication Subspace systems comparison Loop detector nonlinearity Flow models

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Noninvasive Continuous Blood Pressure Measurement and GPS Position Monitoring of Patients

Noninvasive Continuous Blood Pressure Measurement and GPS Po...

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IEEE Conference on Vehicular Technology (VTC)

作者： Ondrej Krejcar Zdenek Slanina Jan Stambachr Petr Silber Robert Frischer Department of Measurement and Control Faculty of Electrical Engineering and Computer Science Technical University of Ostrava Ostrava Czech Republic Department of Automation and Computing in Metallurgy Faculty of Metallurgy And Materials Engineering Technical University of Ostrava Ostrava Czech Republic

ISBN: (纸本)9781424425143

Need of blood pressure measurement is usable in wide spectrum of applications from physicians offices to home care applications. Many types of blood pressure measurement devices can be bought in electronics shops. All such devices are measurement devices which need to be in contact with human body (hand or foot mainly). Further they allow only one measurement per several minutes interval (typically 10 minutes). Our goal is to develop a small device for noninvasive continuous measurement of blood pressure. This device must be a small battery powered embedded system which measures a blood pressure during a long time period and sends this information to remote operator's stations. In this station the analysis of receiving video data is made for several types of usage. In current state we develop a small device to scan a video or a set of images with the NIR (Near Infra Red) CCD camera. The video data are transferred by wireless connection to the computer where they are analyzed. The first results provide an indication to be a right way to obtain exact continuous blood pressure information. In the future there exists a way to integrate this blood pressure measurement system to concurrently developed biotelemetric system architecture for patients and physicians called Guardian. For position monitoring in outdoor areas there is developed GPS module which informs about patient location and brings very precise time basis for other measuring modules of Guardian system and time synchronization.

关键词： Blood pressure Biomedical monitoring Position measurement Pressure measurement Global Positioning System Patient monitoring Battery charge measurement Time measurement Humans Foot

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