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    Wyświetlanie 1-12 z 12
    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:
    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:
    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:
    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:
    Continuous wavelet and Hilbert-Huang Transforms applied for analysis of active and reactive power consumption
    Autorzy:
    Avdakovic, S
    Bosovic, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/221580.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    active power consumption
    reactive power consumption
    continuous wavelet transform (CWT)
    empirical mode decomposition
    Hilbert-Huang transform
    Opis:
    Analysis of power consumption presents a very important issue for power distribution system operators. Some power system processes such as planning, demand forecasting, development, etc.., require a complete understanding of behaviour of power consumption for observed area, which requires appropriate techniques for analysis of available data. In this paper, two different time-frequency techniques are applied for analysis of hourly values of active and reactive power consumption from one real power distribution transformer substation in urban part of Sarajevo city. Using the continuous wavelet transform (CWT) with wavelet power spectrum and global wavelet spectrum some properties of analysed time series are determined. Then, empirical mode decomposition (EMD) and Hilbert-Huang Transform (HHT) are applied for the analyses of the same time series and the results showed that both applied approaches can provide very useful information about the behaviour of power consumption for observed time interval and different period (frequency) bands. Also it can be noticed that the results obtained by global wavelet spectrum and marginal Hilbert spectrum are very similar, thus confirming that both approaches could be used for identification of main properties of active and reactive power consumption time series.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 3; 413-422
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Solution of some problems of single-scale wavelet transform processor using a magnetostatic surface wave device
    Autorzy:
    Lu, W.
    Kuang, L.
    Lü, X.
    Zhu, C.
    Zhang, T.
    Zhang, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/221174.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wavelet transform processor
    magnetostatic surface wave (MSSW)
    interdigital transducer
    direct coupling
    insertion loss
    Opis:
    In this paper, we investigate the implementation schemes of a single-scale wavelet transform processor using magnetostatic surface wave (MSSW) devices. There are three implementation schemes: the interdigital transducer, the meander line transducer and the grating transducer. Because the interdigital transducer has excellent properties, namely, good frequency characteristic and low insertion loss, we use the interdigital transducer as the implementation scheme of a single-scale wavelet transform processor using MSSW device. In the paper, we also present the solutions to the three key problems: the direct coupling between the input transducer and the output transducer, the insertion loss, and the loss characteristics of the gyromagnetic film having an influence on the wavelet transform processor. There are two methods of reducing the direct coupling between the input transducer and the output transducer: increasing the distance between the input transducer and the output transducer, and placing a metal "wall" between the input transducer and the output transducer. There also are two methods of reducing the insertion loss of a single-scale wavelet transform processor using a MSSW device for scale: the appropriate thickness of the yttrium iron garnet (YIG) film and the uniform magnetic field. The smaller the ferromagnetic resonance linewidth of the gyromagnetic film, the smaller the magnetostatic wave propagation loss.
    Źródło:
    Metrology and Measurement Systems; 2012, 19, 4; 685-692
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Novel Approach To Diagnosis Of Analog Circuit Incipient Faults Based On KECA And OAO LSSVM
    Autorzy:
    Zhang, C.
    He, Y.
    Zuo, L.
    Wang, J.
    He, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/221378.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    analog circuits
    incipient fault diagnosis
    wavelet transform
    kernel entropy component analysis
    least squares support vector machine
    Opis:
    Correct incipient identification of an analog circuit fault is conducive to the health of the analog circuit, yet very difficult. In this paper, a novel approach to analog circuit incipient fault identification is presented. Time responses are acquired by sampling outputs of the circuits under test, and then the responses are decomposed by the wavelet transform in order to generate energy features. Afterwards, lower-dimensional features are produced through the kernel entropy component analysis as samples for training and testing a one-against-one least squares support vector machine. Simulations of the incipient fault diagnosis for a Sallen-Key band-pass filter and a two-stage four-op-amp bi-quad low-pass filter demonstrate the diagnosing procedure of the proposed approach, and also reveal that the proposed approach has higher diagnosis accuracy than the referenced methods.
    Źródło:
    Metrology and Measurement Systems; 2015, 22, 2; 251-262
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Anatomical and functional assessment of patency of the upper respiratory tract in selected respiratory disorders - Part 1
    Autorzy:
    Kukwa, Andrzej
    Zając, Andrzej
    Barański, Robert
    Nitkiewicz, Szymon
    Kukwa, Wojciech
    Zomkowska, Edyta
    Rybak, Adam
    Powiązania:
    https://bibliotekanauki.pl/articles/2052154.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    optical diagnostic in otolaryngology
    upper respiratory tract diagnostics
    otolaryngology
    spirometer
    Fourier transform
    wavelet transform
    quantitative parameters of the respiratory cycle
    Opis:
    The rapidly developing measurement techniques and emerging new physical methods are frequently used in otolaryngological diagnostics. A wide range of applied diagnostic methods constituted the basis for the review study aimed at presenting selected modern diagnostic methods and achieved diagnostic results to a wider group of users. In this part, the methods based on measuring the respiratory parameters of patients were analysed. Respiration is the most important and necessary action to support life and its effective duration. It is an actual gas exchange in the respiratory system consisting of removing CO2 and supplying O2. Gas exchange occurs in the alveoli, and an efficient respiratory tract allows for effective ventilation. The disruption in the work of the respiratory system leads to measurable disturbances in blood saturation and, consequently, hypoxia. Frequent, even short-term, recurrent hypoxia in any part of the body leads to multiple complications. This process is largely related to its duration and the processes that accompany it. The causes of hypoxia resulting from impaired patency of the respiratory tract and/or the absence of neuronal respiratory drive can be divided into the following groups depending on the cause: peripheral, central and/or of mixed origin. Causes of the peripheral form of these disorders are largely due to the impaired patency of the upper and/or lower respiratory tract. Therefore, early diagnosis and location of these disorders can be considered reversible and not a cause of complications. Slow, gradually increasing obstruction of the upper respiratory tract (URT) is not noticeable and becomes a slow killer. Hypoxic individuals in a large percentage of cases have a shorter life expectancy and, above all, deal with the consequences of hypoxia much sooner.
    Źródło:
    Metrology and Measurement Systems; 2021, 28, 4; 813-836
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Anatomical and functional assessment of patency of the upper respiratory tract in selected respiratory disorders - Part 2
    Autorzy:
    Zając, Andrzej
    Kukwa, Andrzej
    Barański, Robert
    Nitkiewicz, Szymon
    Zomkowska, Edyta
    Rybak, Adam
    Powiązania:
    https://bibliotekanauki.pl/articles/2173877.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    optical diagnostic in otolaryngology
    upper respiratory tract diagnostics
    otolaryngology
    spirometer
    Fourier transform
    wavelet transform
    quantitative parameters of the respiratory cycle
    Opis:
    This article presents selected physical diagnostic methods used in otorhinolaryngology and results of their application. In addition to the applications of methods using the capabilities of selective sensors, selected methods of hybrid diagnostics were also presented - for assessment of parameters of respiratory processes, with polysomnography as an example of using both typical diagnostic methods dedicated to otolaryngology, as well as standard EEG and ECG methods. It has been shown that in some special cases of respiratory disorders, measurements of the air flow in the respiratory tract can be supplemented with pressure measurements in selected positions within the airways. The presented optical methods and diagnostic systems are very often used in the diagnosis of diseases not specific for otolaryngology occurring in the area of the head and neck. The presented material is the second part of the study discussing both standard and widely used diagnostic methods. All presented methods are dedicated to otolaryngology. This text is a continuation of the material published in No 4 of 2021 [1].
    Źródło:
    Metrology and Measurement Systems; 2022, 29, 3; 429--454
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Feature Extraction on Automatic Sleep Stage Classification by Artificial Neural Network
    Autorzy:
    Prucnal, M.
    Polak, A. G.
    Powiązania:
    https://bibliotekanauki.pl/articles/220360.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    sleep stage classification
    EEG signal
    power spectral density
    discrete wavelet transform
    empirical mode decomposition
    artificial neural network
    Opis:
    EEG signal-based sleep stage classification facilitates an initial diagnosis of sleep disorders. The aim of this study was to compare the efficiency of three methods for feature extraction: power spectral density (PSD), discrete wavelet transform (DWT) and empirical mode decomposition (EMD) in the automatic classification of sleep stages by an artificial neural network (ANN). 13650 30-second EEG epochs from the PhysioNet database, representing five sleep stages (W, N1-N3 and REM), were transformed into feature vectors using the aforementioned methods and principal component analysis (PCA). Three feed-forward ANNs with the same optimal structure (12 input neurons, 23 + 22 neurons in two hidden layers and 5 output neurons) were trained using three sets of features, obtained with one of the compared methods each. Calculating PSD from EEG epochs in frequency sub-bands corresponding to the brain waves (81.1% accuracy for the testing set, comparing with 74.2% for DWT and 57.6% for EMD) appeared to be the most effective feature extraction method in the analysed problem.
    Źródło:
    Metrology and Measurement Systems; 2017, 24, 2; 229-240
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Joint time-frequency and wavelet analysis - an introduction
    Autorzy:
    Majkowski, A.
    Kołodziej, M.
    Rak, R. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/220841.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    frequency analysis
    time-frequency analysis
    short-time Fourier transform
    Gabor transform
    Wigner-Ville transform
    Cone-Shaped Transform
    wavelet analysis
    time-scale analysis
    wavelet decomposition
    filter banks
    wavelet packets
    Opis:
    A traditional frequency analysis is not appropriate for observation of properties of non-stationary signals. This stems from the fact that the time resolution is not defined in the Fourier spectrum. Thus, there is a need for methods implementing joint time-frequency analysis (t/f) algorithms. Practical aspects of some representative methods of time-frequency analysis, including Short Time Fourier Transform, Gabor Transform, Wigner-Ville Transform and Cone-Shaped Transform are described in this paper. Unfortunately, there is no correlation between the width of the time-frequency window and its frequency content in the t/f analysis. This property is not valid in the case of a wavelet transform. A wavelet is a wave-like oscillation, which forms its own “wavelet window”. Compression of the wavelet narrows the window, and vice versa. Individual wavelet functions are well localized in time and simultaneously in scale (the equivalent of frequency). The wavelet analysis owes its effectiveness to the pyramid algorithm described by Mallat, which enables fast decomposition of a signal into wavelet components.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 4; 741-758
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Infrared devices and techniques (revision)
    Autorzy:
    Rogalski, A.
    Chrzanowski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/221154.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    frequency analysis
    time-frequency analysis
    short-time Fourier transform
    Gabor transform
    Wigner-Ville transform
    Cone-Shaped Transform
    wavelet analysis
    time-scale analysis
    wavelet decomposition
    filter banks
    wavelet packets
    Opis:
    The main objective of this paper is to produce an applications-oriented review covering infrared techniques and devices. At the beginning infrared systems fundamentals are presented with emphasis on thermal emission, scene radiation and contrast, cooling techniques, and optics. Special attention is focused on night vision and thermal imaging concepts. Next section concentrates shortly on selected infrared systems and is arranged in order to increase complexity; from image intensifier systems, thermal imaging systems, to space-based systems. In this section are also described active and passive smart weapon seekers. Finally, other important infrared techniques and devices are shortly described, among them being: non-contact thermometers, radiometers, LIDAR, and infrared gas sensors.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 4; 565-618
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-12 z 12

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