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Wyświetlanie 1-15 z 46
Tytuł:
An analysis of deviations of cylindrical surfaces with the use of wavelet transform
Autorzy:
Stępień, K.
Makieła, W.
Powiązania:
https://bibliotekanauki.pl/articles/220818.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wavelet transform
cylindricity profile
decomposition
approximation
Opis:
Wavelet transform becomes a more and more common method of processing 3D signals. It is widely used to analyze data in various branches of science and technology (medicine, seismology, engineering, etc.). In the field of mechanical engineering wavelet transform is usually used to investigate surface micro- and nanotopography. Wavelet transform is commonly regarded as a very good tool to analyze non-stationary signals. However, to analyze periodical signals, most researchers prefer to use well-known methods such as Fourier analysis. In this paper authors make an attempt to prove that wavelet transform can be a useful method to analyze 3D signals that are approximately periodical. As an example of such signal, measurement data of cylindrical workpieces are investigated. The calculations were performed in the MATLAB environment using the Wavelet Toolbox.
Źródło:
Metrology and Measurement Systems; 2013, 20, 1; 139-150
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wavelet-based Entropy Measure for Rate-Distortion Optimization in Image Coding
Autorzy:
Garcia-Alvarez, J.
Führ, H.
Castellanos-Dominguez, G.
Powiązania:
https://bibliotekanauki.pl/articles/226142.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
entropy
wavelet transform
information measure
rate distortion
Opis:
A novel method for calculation of the entropy measure in wavelet space is proposed. This perceived-based entropy measure uses a Second Order Model entropy estimator, in which the occurrence of neighbors is considered in formulation. It has the intention to allow the implementation of a more suitable measure in coding processes and a relationship between the metric and the description of perceptual features. This method is used for the Rate-Distortion optimization in order to improve the bit-allocation coding algorithm, demonstrating that the wavelet-based entropy estimates a truncation step close to the target rate. The hypothesis is founded in the effect of distortion on the coefficient allocation. Because entropy measure is a close approximation of the conditional probability of image in multiresolution space, it provides an adequate representation for the information of a Detail feature. A definition of Detail-based homogeneity variance criteria is used for the information quantity - wavelet representation space, in order to find the image that fits a given Quality Level criteria. Experimental results are obtained for artificial and natural databases.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 1; 25-31
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phoneme Segmentation Based on Wavelet Spectra Analysis
Autorzy:
Ziółko, B.
Manandhar, S.
Wilson, R. C.
Ziółko, M.
Powiązania:
https://bibliotekanauki.pl/articles/177480.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
speech recognition
speech segmentation
discrete wavelet transform
Opis:
A phoneme segmentation method based on the analysis of discrete wavelet transform spectra is described. The localization of phoneme boundaries is particularly useful in speech recognition. It enables one to use more accurate acoustic models since the length of phonemes provide more information for parametrization. Our method relies on the values of power envelopes and their first derivatives for six frequency subbands. Specific scenarios that are typical for phoneme boundaries are searched for. Discrete times with such events are noted and graded using a distribution-like event function, which represent the change of the energy distribution in the frequency domain. The exact definition of this method is described in the paper. The final decision on localization of boundaries is taken by analysis of the event function. Boundaries are, therefore, extracted using information from all subbands. The method was developed on a small set of Polish hand segmented words and tested on another large corpus containing 16 425 utterances. A recall and precision measure specifically designed to measure the quality of speech segmentation was adapted by using fuzzy sets. From this, results with F-score equal to 72.49% were obtained.
Źródło:
Archives of Acoustics; 2011, 36, 1; 29-47
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of analog circuit based on wavelet transform and neural network
Autorzy:
Wang, Hui
Powiązania:
https://bibliotekanauki.pl/articles/141368.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuit
fault diagnosis
neural network
wavelet transform
Opis:
Analog circuits need more effective fault diagnosis methods. In this study, the fault diagnosis method of analog circuits was studied. The fault feature vectors were extracted by a wavelet transform and then classified by a generalized regression neural network (GRNN). In order to improve the classification performance, a wolf pack algorithm (WPA) was used to optimize the GRNN, and a WPA-GRNN diagnosis algorithm was obtained. Then a simulation experiment was carried out taking a Sallen–Key bandpass filter as an example. It was found from the experimental results that the WPA could achieve the preset accuracy in the eighth iteration and had a good optimization effect. In the comparison between the GRNN, genetic algorithm (GA)-GRNN and WPA-GRNN, the WPA-GRNN had the highest diagnostic accuracy, and moreover it had high accuracy in diagnosing a single fault than multiple faults, short training time, smaller error, and an average accuracy rate of 91%. The experimental results prove the effectiveness of the WPA-GRNN in fault diagnosis of analog circuits, which can make some contributions to the further development of the fault diagnosis of analog circuits.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 175-185
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Autocorrelation Bark Wavelet Transform (PACWT) Features for Robust Speech Recognition
Autorzy:
Majeed, S. A.
Husain, H.
Samad, S. A.
Powiązania:
https://bibliotekanauki.pl/articles/177326.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
speech recognition
feature extraction
phase autocorrelation
wavelet transform
Opis:
In this paper, a new feature-extraction method is proposed to achieve robustness of speech recognition systems. This method combines the benefits of phase autocorrelation (PAC) with bark wavelet transform. PAC uses the angle to measure correlation instead of the traditional autocorrelation measure, whereas the bark wavelet transform is a special type of wavelet transform that is particularly designed for speech signals. The extracted features from this combined method are called phase autocorrelation bark wavelet transform (PACWT) features. The speech recognition performance of the PACWT features is evaluated and compared to the conventional feature extraction method mel frequency cepstrum coefficients (MFCC) using TI-Digits database under different types of noise and noise levels. This database has been divided into male and female data. The result shows that the word recognition rate using the PACWT features for noisy male data (white noise at 0 dB SNR) is 60%, whereas it is 41.35% for the MFCC features under identical conditions.
Źródło:
Archives of Acoustics; 2015, 40, 1; 25-31
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analyzing the variations in roundness profile parameters during the wavelet decomposition process using the MATLAB environment
Autorzy:
Adamczak, S.
Makieła, W.
Powiązania:
https://bibliotekanauki.pl/articles/221022.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mother wavelet
Fourier transform
wavelet transform
surface texture
surface roundness
roundness profile parameters
Opis:
Signal analysis performed during surface texture measurement frequently involves applying the Fourier transform. The method is particularly useful for assessing roundness and cylindrical profiles. Since the wavelet transform is becoming a common tool for signal analysis in many metrological applications, it is vital to evaluate its suitability for surface texture profiles. The research presented in this paper focused on signal decomposition and reconstruction during roundness profile measurement and the effect of these processes on the changes in selected roundness profile parameters. The calculations were carried out on a sample of 100 roundness profiles for 12 different forms of mother wavelets using MATLAB. The use of Spearman's rank correlation coefficients allowed us to evaluate the relationship between the two chosen criteria for selecting the optimal mother wavelet.
Źródło:
Metrology and Measurement Systems; 2011, 18, 1; 25-33
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of wavelet transform into precise localization of railway rail edges in visual diagnostic of track
Zastosowanie transformaty falkowej do precyzyjnego określania krawędzi szyn dla celów diagnostyki wizyjnej toru
Autorzy:
Bojarczak, P.
Powiązania:
https://bibliotekanauki.pl/articles/224243.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transformata falkowa
diagnostyka toru
wavelet transform
diagnostic of trock
Opis:
The paper presents the application of wavelet transform into precise localization of railway rail edges. The precise localization of inner edges of the rail is particularly crucial in detection of surface flaws by the vision system. The proposed method uses the multi-resolution analysis in detection of rail edges. Application of the wavelet transform and the choice of the right combination of decomposition levels along with wavelet type immunizes the proposed algorithm against the variation of luminance of analyzing image. The algorithm is additionally resistant to shadows incidentally appearing in analyzing images. The performance of algorithm has been tested on the images coming from real vision system installed on the carriage.
W artykule przedstawiono zastosowanie transformaty falkowej do precyzyjnego określania krawędzi szyny. Jest to szczególnie istotny problem, mający wpływ na jakość działania algorytmów wizyjnej detekcji wad powierzchniowych szyn w torze. Dzięki zastosowaniu transformaty falkowej pozwaląjącej na jednoczesną analizę w dziedzinie przestrzennej oraz wyborze odpowiedniej kombinacji poziomów dekompozycji i odpowiedniego typu falki, zaproponowane rozwiązanie jest odporne na zmiany luminancji analizowanych obrazów jak również redukuje do minimum wpływ cieni i odblasków w nich występujących. Dzięki temu system wizyjny nie musi być wyposażony w dodatkowe osłony. Działanie algorytmu zostało przetestowane na losowo wybranych z bazy systemu wizyjnego obrazach zarejestrowanych wagonem diagnostycznym.
Źródło:
Archives of Transport; 2012, 24, 1; 5-16
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustical Analysis of Enclosure as Initial Approach to Vehicle Induced Noise Analysis Comparatevely Using STFT and Wavelets
Autorzy:
Błażejewski, A.
Kozioł, P.
Łuczak, M.
Powiązania:
https://bibliotekanauki.pl/articles/176551.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modal analysis
short-time Fourier transform
wavelet transform
acoustic signal processing
Opis:
It is assumed in the paper that the signals in the enclosure in a transient period are similar to a noise induced by vehicles, tracks, cars, etc. passing by. The components of such signals usually points out specific dynamic processes running during the observation or measurements. In order to choose the best method of analysis of these phenomena, an acoustic field in a closed space with a sound source inside is created. Acoustic modes of this space influence the sound field. Analytically, the modal analyses describe the above mentioned phenomena. The experimental measurements were conducted in the room that might comprise the closed space with known boundary conditions and the sound source Br¨uel & Kjær Omni-directional type 4292 inside. To record sound signals before the field’s steady state was reached, the microphone type 4349 and the 4-channel frontend 3590 had been used. The obtained signals have been analysed by using two approaches, i.e. Fourier and the wavelet analysis, with the emphasis on their efficiency and the capability to recognise important details of the signal. The results obtained for the enclosure might lead to the formulation of a methodology for an extended investigation of a rail track or vehicles dynamics.
Źródło:
Archives of Acoustics; 2014, 39, 3; 385-394
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Lifting Wavelet Domain Audio Watermarking Algorithm Based on the Statistical Characteristics of Sub-Band Coefficients
Autorzy:
Tao, Z.
Zhao, H.
Wu, J.
Gu, J.
Xu, Y.
Wu, D.
Powiązania:
https://bibliotekanauki.pl/articles/177956.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
audio watermarking
lifting wavelet transform
statistical characteristics
sub-band coefficients
Opis:
In this paper, a new lifting wavelet domain audio watermarking algorithm based on the statistical characteristics of sub-band coefficients is proposed. First of all, an original audio signal was segmented and each segment was divided into two sections. Then, the Barker code was used for synchronization, the LWT (lifting wavelet transform) was performed on each section, a synchronization code and a watermark were embedded into the first section and the second section, respectively, by modifying the statistical average value of the sub-band coefficients. The embed strength was determined adaptively according to the auditory masking property. Experiments show that the embedded watermark has better robustness against common signal processing attacks than present algorithms based on LWT and can resist random cropping in particular.
Źródło:
Archives of Acoustics; 2010, 35, 4; 481-491
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving energy compaction of a wavelet transform using genetic algorithm and fast neural network
Autorzy:
Stolarek, J.
Powiązania:
https://bibliotekanauki.pl/articles/964025.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wavelet transform
neural networks
genetic algorithms
signal processing
lattice structure
Opis:
In this paper a new method for adaptive synthesis of a smooth orthogonal wavelet, using fast neural network and genetic algorithm, is introduced. Orthogonal lattice structure is presented. A new method of supervised training of fast neural network is introduced to synthesize a wavelet with desired energy distribution between output signals from low–pass and high–pass filters on subsequent levels of a Discrete Wavelet Transform. Genetic algorithm is proposed as a global optimization method for defined objective function, while neural network is used as a local optimization method to further improve the result. Proposed approach is tested by synthesizing wavelets with expected energy distribution between low– and high–pass filters. Energy compaction of proposed method and Daubechies wavelets is compared. Tests are performed using image signals.
Źródło:
Archives of Control Sciences; 2010, 20, 4; 417-433
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiscale assessment of additively manufactured free-form surfaces
Autorzy:
Gogolewski, Damian
Powiązania:
https://bibliotekanauki.pl/articles/2203371.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
free-form
wavelet transform
multiscale analysis
surface texture
additive manufacturing
Opis:
The article reviews the results of experimental tests assessing the impact of process parameters of additive manufacturing technologies on the geometric structure of free-form surfaces. The tests covered surfaces manufactured with the Selective Laser Melting additive technology, using titanium-powder-based material (Ti6Al4V) and Selective Laser Sintering from polyamide PA2200. The evaluation of the resulting surfaces was conducted employing modern multiscale analysis, i.e., wavelet transformation. Comparative studies using selected forms of the mother wavelet enabled determining the character of irregularities, size of morphological features and the indications of manufacturing process errors. The tests provide guidelines and allow to better understand the potential in manufacturing elements with complex, irregular shapes.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 157--168
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Are Stock Prices Hedge Against Inflation? A Revisit over Time and Frequencies in India
Autorzy:
Bhanja, Niyati
Dar, Arif Billah
Tiwari, Aviral Kumar
Powiązania:
https://bibliotekanauki.pl/articles/483267.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Stock prices
inflation
Fisher effect
Indian stock markets
continuous wavelet transform
wavelet coherency
Opis:
In this paper, the stock price-inflation nexus is investigated using the tools of wavelet power spectrum, cross-wavelet power spectrum and cross-wavelet coherency to unravel time and frequency dependent relationships between stock prices and inflation. Our results suggest that for a frequency band between sixteen and thirty two months, there is some evidence of the fisher effect. For rest of the frequencies and time periods however there is no evidence of the fisher effect and it seems stock prices have not played any role as an inflation hedge.
Źródło:
Central European Journal of Economic Modelling and Econometrics; 2012, 4, 3; 199-213
2080-0886
2080-119X
Pojawia się w:
Central European Journal of Economic Modelling and Econometrics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fall Detector Using Discrete Wavelet Decomposition And SVM Classifier
Autorzy:
Wójtowicz, B.
Dobrowolski, A.
Tomczykiewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/220495.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fall detection
discrete wavelet transform
data fusion
support vector machine (SVM)
Opis:
This paper presents the design process and the results of a novel fall detector designed and constructed at the Faculty of Electronics, Military University of Technology. High sensitivity and low false alarm rates were achieved by using four independent sensors of varying physical quantities and sophisticated methods of signal processing and data mining. The manuscript discusses the study background, hardware development, alternative algorithms used for the sensor data processing and fusion for identification of the most efficient solution and the final results from testing the Android application on smartphone. The test was performed in four 6-h sessions (two sessions with female participants at the age of 28 years, one session with male participants aged 28 years and one involving a man at the age of 49 years) and showed correct detection of all 40 simulated falls with only three false alarms. Our results confirmed the sensitivity of the proposed algorithm to be 100% with a nominal false alarm rate (one false alarm per 8 h).
Źródło:
Metrology and Measurement Systems; 2015, 22, 2; 303-314
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Heart Rate Variability Fluctuations by Wavelet Transform
Autorzy:
Popov, A.
Karplyuk, Y.
Fesechko, V.
Powiązania:
https://bibliotekanauki.pl/articles/226306.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heart rate variability
HRV fluctuations
HRV wavelet analysis
time-dependent HRV estimation
wavelet transform
Opis:
Technique for separate estimation of fast and slow fluctuations in the heart rate signal is developed. The orthogonal dyadic wavelet transform is used to separate the slow heart rate changes in approximation part of decomposition and fast changes in detail parts. Experimental results using the recordings from persons practicing Chi meditation demonstrated the applicability of estimation heart rate fluctuations with the proposed approach.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 3; 395-400
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Speech Enhancement Based on the Multi-Scales and Multi-Thresholds of the Auditory Perception Wavelet Transform
Autorzy:
Tao, Z.
Zhao, H. M.
Zhang, X-J.
Wu, D.
Powiązania:
https://bibliotekanauki.pl/articles/177021.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
speech enhancement
low SNR
auditory perception wavelet transform
unvoiced enhancement
masking effect
Opis:
This paper proposes a speech enhancement method using the multi-scales and multi-thresholds of the auditory perception wavelet transform, which is suitable for a low SNR (signal to noise ratio) environment. This method achieves the goal of noise reduction according to the threshold processing of the human ear’s auditory masking effect on the auditory perception wavelet transform parameters of a speech signal. At the same time, in order to prevent high frequency loss during the process of noise suppression, we first make a voicing decision based on the speech signals. Afterwards, we process the unvoiced sound segment and the voiced sound segment according to the different thresholds and different judgments. Lastly, we perform objective and subjective tests on the enhanced speech. The results show that, compared to other spectral subtractions, our method keeps the components of unvoiced sound intact, while it suppresses the residual noise and the background noise. Thus, the enhanced speech has better clarity and intelligibility.
Źródło:
Archives of Acoustics; 2011, 36, 3; 519-532
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 46

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