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Tytuł:
Frequency Analysis with Cross-Correlation Envelope Approach
Autorzy:
Kotowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/387638.pdf
Data publikacji:
2012
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
analiza częstotliwości
transformacja Hilberta
frequency analysis
cross-correlation
Hilbert transform
envelope
Opis:
A new approach for frequency analysis of recorded signals and readout the frequency of harmonics is presented in the paper. The main purpose has been achieved by the cross$correlation function and Hilbert transform. Using the method presented in the paper, there is another possibility to observe and finally to identify single harmonic apart from commonly used Fourier transform. Identification of the harmonic is based on the effect of a straight line of the envelope of the cross$correlation function when reference and signal harmon$ ic have the same frequency. This particular case is the basis for pointing the value of the frequency of harmonic component detected.
Źródło:
Acta Mechanica et Automatica; 2012, 6, 4; 27-31
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency analysis of preconditioned waveform relaxation iterations
Autorzy:
Augustynowicz, Andrzej
Jackiewicz, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/1338848.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
error analysis
waveform relaxation
convergence
preconditioning
splitting
Opis:
The error analysis of preconditioned waveform relaxation iterations for differential systems is presented. This analysis extends and refines previous results by Burrage, Jackiewicz, Nørsett and Renaut by incorporating all terms in the expansion of the error of waveform relaxation iterations in the Laplace transform domain. Lower bounds for the size of the window of rapid convergence are also obtained. The theory is illustrated for waveform relaxation methods applied to differential systems resulting from semi-discretization of the heat equation in one and two dimensions. This theory and some heuristic arguments predict that preconditioning is most effective for the first few iterations.
Źródło:
Applicationes Mathematicae; 1999, 26, 2; 229-242
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency analysis of a double-nanobeam system
Autorzy:
Ciekot, A.
Kukla, S.
Powiązania:
https://bibliotekanauki.pl/articles/122395.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
nanobeam system
free vibration
Green's functions
drgania swobodne
funkcja Greena
wyniki obliczeń numerycznych
Opis:
In this paper, a problem of transverse free vibration of a double-nanobeam-system is considered. The nanobeams of the system are coupled by an arbitrary number of translational springs. The solution of the problem by using the Green’s functions properties is obtained. A numerical example is presented.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 1; 23-31
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency Analysis of Noise Generated by Pneumatic Wheels
Autorzy:
Warczek, J.
Burdzik, R.
Konieczny, Ł.
Siwiec, G.
Powiązania:
https://bibliotekanauki.pl/articles/176356.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
noise of pneumatic tire wheels
analysis of the frequency components of noise
station for testing tires
Opis:
The dominant sources of traffic noise, which are linked directly to the vehicle, are dependent on the speed. In terms of speed of 50–120 km/h the dominant source of noise is pneumatic wheels. The aim of the research was chosen to develop a method and experimental determination of the dominant frequency components of noise generated by the car tire. For the purpose of the study and on the basis of the analysis of the source data it was assumed that there is a relationship between the vibration of the tread elements and emitted noise, especially for low and medium frequencies. Thus, the target was set on the basis of the own method of research in the built measuring station. Based on the survey and the obtained results it can be stated that in the spectrum of the noise emitted by the tires the frequency components are dominant. Non-directional tire structure includes more frequency components which at the speed adopted in the studies are located at a greater frequency range than it is for the directional tire. In the case of a tire with a directional tread, acoustic emission energy is more associated with specific frequency components. The developed method provides results independent from the influence of the type of road surface on the acoustic emission while driving.
Źródło:
Archives of Acoustics; 2017, 42, 3; 459-467
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time–frequency Analysis of the EMG Digital Signals
Autorzy:
Kuniszyk-Jóźkowiak, W.
Jaszczuk, J.
Sacewicz, T.
Codello, I.
Powiązania:
https://bibliotekanauki.pl/articles/106250.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
time-frequency analysis
EMG signal
Fast Fourier Transform
predictive analytics
wavelet analysis
Opis:
In the article comparison of time-frequency spectra of EMG signals obtained by the following methods: Fast Fourier Transform, predictive analysis and wavelet analysis is presented. The EMG spectra of biceps and triceps while an adult man was flexing his arm were analysed. The advantages of the predictive analysis were shown as far as averaging of the spectra and determining the main maxima are concerned. The Continuous Wavelet Transform method was applied, which allows for the proper distribution of the scales, aiming at an accurate analysis and localisation of frequency maxima as well as the identification of impulses which are characteristic of such signals (bursts) in the scale of time. The modified Morlet wavelet was suggested as the mother wavelet. The wavelet analysis allows for the examination of the changes in the frequency spectrum in particular stages of the muscle contraction. Predictive analysis may also be very useful while smoothing and averaging the EMG signal spectrum in time.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2012, 12, 2; 20-25
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency analysis of a double-walled nanotubes system
Autorzy:
Ciekot, A.
Kukla, S.
Powiązania:
https://bibliotekanauki.pl/articles/122756.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
nanotubes system
free vibration
Green's functions
drgania swobodne
funkcja Greena
Opis:
In the present paper, a problem of free vibration of a double-walled nanotubes system is considered. The nanotubes of the system are coupled by an arbitrary number of elastic rings. The Green’s functions method was used to obtain a solution to the problem. Numerical results are presented graphically.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 4; 27-34
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The frequency analysis of real resistors in relative values
Autorzy:
Kubisa, S.
Warsza, Z. L.
Powiązania:
https://bibliotekanauki.pl/articles/114711.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
resistor
AC models
equivalent circuits
impedance
parameters
frequency errors
Opis:
Three-element impedance including the resistance R as the main parameter and the residual parameters: serial inductance L and a parallel capacitance C is used as an equivalent circuit of resistor. It is the basic model of resistor for AC current. The real component of this impedance is not equal to the resistance R for the DC current, and there is the imaginary component. Both components depend on the frequency. Variants of the model with four different connections are also analyzed. Patterns of the relative resistor frequency errors in the generalized form, i.e. as a function of the relative values of resistance and frequency of the circuit are determined and their curves are given. Considerations are illustrated by few numerical examples
Źródło:
Measurement Automation Monitoring; 2016, 62, 3; 80-86
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-frequency analysis of seabed echoes using wavelet transform
Autorzy:
Moszyński, M.
Stepnowski, A.
Łubniewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332256.pdf
Data publikacji:
1999
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The methods based on analysis of boftom backscatter data from a single-beam echosounder have achieved special attention in the seabed identification problem. due to their simplicity over ofher more sophisticated acoustic techniques like side scan sonar or multibeam surveys. The majority of these methods analyses the scattering phenomena mostly in time domain (echo envelope). However, the frequency echo components carry concurrent information, which can be also used in boftom characterisation. The paper proposes the time-frequency approach to the boftom characterisation and presents the application of Wigner- Ville Distribution and wavelet transform of boftom backscatter data. The examples of continuous and discrete wavelet transforms of actual echo envelopes received at three boftom types for three different operating frequencies (38, 120 and 420 kHz) are shown. Their characteristic features are compared and parameters for classification schemes are proposed. The results of classification procedure are good with comparison with those of ofher simple acoustic methods.
Źródło:
Hydroacoustics; 1999, 2; 85-90
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel method of time-frequency analysis: an essential spectrogram
Autorzy:
Czarnecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/332003.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
A novel precise method of time-frequency analysis is presented. In the algorithm, a new energy distribution is estimated by simultaneously discard or displacement of the classical spectrogram energy. A channelized instantaneous frequency and a local group delay are used in order to replacement in the same manner as formulated by Kodera et al. [1, 2]. Additionally, new representations: a channelized instantaneous bandwidth and a local group duration are used in order to remove some part of irrelevant energy. A newly obtained energy distribution called essential spectrogram is highly concentrated and signal mono-components are precisely localized in the time-frequency domain.
Źródło:
Hydroacoustics; 2013, 16; 29-34
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grammatical typology and frequency analysis : number availability and number use
Autorzy:
Brown, D.
Corbett, G. G.
Fedden, S.
Hippisley, A.
Marriott, P.
Powiązania:
https://bibliotekanauki.pl/articles/103829.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Podstaw Informatyki PAN
Tematy:
animacy hierarchy
frequency
number
Russian
Opis:
The Smith-Stark hierarchy, a version of the Animacy Hierarchy, offers a typology of the cross-linguistic availability of number. The hierarchy predicts that the availability of number is not arbitrary. For any language, if the expression of plural is available to a noun, it is available to any noun of a semantic category further to the left of the hierarchy. In this article we move one step further by showing that the structure of the hierarchy can be observed in a statistical model of number use in Russian. We also investigate three co-variates: plural preference, pluralia tantum and irregularity effects; these account for an item’s behaviour being different than that solely expected from its animacy position.
Źródło:
Journal of Language Modelling; 2013, 1, 2; 227-241
2299-856X
2299-8470
Pojawia się w:
Journal of Language Modelling
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of Time-Frequency Analysis in Authentication of Digital Audio Recordings
Autorzy:
Korycki, R.
Powiązania:
https://bibliotekanauki.pl/articles/226798.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tampering detection
audio authenticity analysis
media authentication
electric network frequency
time-frequency analysis
digital audio forensics
inverse decoder
MP3
compressed audio
perceptual audio coding
Opis:
This paper describes the problem of tampering detection and discusses the main methods used for authenticity analysis of digital audio recordings. For the first topic, two frequency measurement algorithms based on electric network frequency criterion are applied. Time-frequency analysis is used and improved with reassignment method for purpose of visual inspection of modified recordings. The algorithms are shortly described and exemplary plots are presented with interpretation. The last described method, recently proposed, is based on checking frame offsets in compressed audio files.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 3; 257-262
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The natural frequency analysis of a wind turbine with vertical axes
Autorzy:
Mazur, D.
Szczepański, A.
Rudy, M.
Powiązania:
https://bibliotekanauki.pl/articles/114730.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
natural frequency analysis
wind turbine
vibrations
Opis:
The natural frequency analysis of four analytical models of a home wind turbine is presented in this paper. These models are: the rotor of a generator without housing, the rotor of a generator with housing and a stator, the rotor of a wind turbine, and the entire assembly of the wind turbine. By comparison of the received results of these models, evaluation of the variation in natural frequencies was performed. Additionally, interaction of the natural frequencies of the models with excitations was investigated. Moreover, various forms of vibrations, such as bending and torsional mode of the wind turbine rotor, rotor generator and blades, were found. Simplified analytical calculations for evaluation of the bearing stiffness applied to the vibration models were also carried out. The natural frequency analysis was performed in the analytical environment of the Siemens NX software based on NX Advanced module by the use of NASTRAN solver.
Źródło:
Measurement Automation Monitoring; 2015, 61, 12; 535-537
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza czasowo-częstotliwościowa sygnału EKG
Time-frequency analysis of ECG signal
Autorzy:
Pieniężny, A.
Powiązania:
https://bibliotekanauki.pl/articles/208548.pdf
Data publikacji:
2009
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
analiza czasowo-częstotliwościowa
sygnał EKG
analiza sygnałów biomedycznych
time-frequency analysis
ECG signal
biomedical signals - analysis
Opis:
Sygnały biomedyczne stanowią bardzo szczególną klasę sygnałów zarówno ze względu na ich strukturę, jak i szczególne podejście do ich analizy. Są one sygnałami niestacjonarnymi. Podstawowe metody analizy tego typu sygnałów obejmują analizę czasową i częstotliwościową, realizowane rozdzielnie. Rozdzielność analizy czasowej i częstotliwościowej sygnałów biomedycznych nie pozwala na pełną diagnozę z uwagi na zmienność ich struktury częstotliwościowej w czasie. Artykuł przedstawia pewne wyniki czasowo-częstotliwościowej analizy sygnału EKG.
Biomedical signals are specific type of signals due to their structure and specific approach to their analysis. They are usually non-stationary signals. Basic methods of analysis include time and frequency analyses performed separately. Frequency structure of biomedical signals varies in time so, patient diagnose could be better when time-frequency analysis concept will be applied. The paper presents some results of time-frequency analysis of ECG signal.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2009, 58, 1; 269-279
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EMD-based time-frequency analysis methods of non-stationary audio signals
Autorzy:
Lewandowski, Marcin
Grodzicka, Salomea
Powiązania:
https://bibliotekanauki.pl/articles/2202413.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
empirical mode decomposition
non-stationary audio data
time-frequency analysis
empiryczna metoda dekompozycji
niestacjonarne dane dźwiękowe
analiza czasowo-częstotliwościowa
Opis:
To ensure that any time series data is appropriately interpreted, it should be analyzed with proper signal processing tools. The most common analysis methods are kernel-based transforms, which use base functions and their modifications to represent time series data. This work discusses an analysis of audio data and two of those transforms - the Fourier transform and the wavelet transform based on a priori assumptions about the signal's linearity and stationarity. In audio engineering, these assumptions are invalid because the statistical parameters of most audio signals change with time and cannot be treated as an output of the LTI system. That is why recent approaches involve decomposition of a signal into different modes in a data-dependent and adaptive way, which may provide advantages over kernel-based transforms. Examples of such methods include empirical mode decomposition (EMD), ensemble EMD (EEMD), variational mode decomposition (VMD), or singular spectrum analysis (SSA). Simulations were performed with speech signal for kernel-based and data-dependent decomposition methods, which revealed that evaluated decomposition methods are promising approaches to analyzing non-stationary audio data.
Źródło:
Vibrations in Physical Systems; 2022, 33, 2; art. no. 2022215
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Virtual Instrument for Time-Frequency Analysis of Park Power Components
Autorzy:
Monti, A.
Ponci, F.
Pelizzari, S.
Cristaldi, L.
Powiązania:
https://bibliotekanauki.pl/articles/262659.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Opis:
The paper presents an implementation of a virtual instrument to perform wavelet analysis on the Park Power components. The main purpose of the analysis is an automatic detection of load in a power system applying load signature analysis. A justification for the approach is presented, followed by the details about the specific implementation performed in the laboratory. Finally a preliminary testing activity based on the use of Hardware in the Loop approach is also presented.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2007, 13, 1; 121-128
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 399

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