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Wyświetlanie 211-225 z 225
Tytuł:
Stator winding fault detection of permanent magnet synchronous motors based on the bispectrum analysis
Autorzy:
Pietrzak, Przemysław
Wolkiewicz, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2173641.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault diagnosis
condition monitoring
inter-turn short circuits
permanent magnet synchronous motor
bispectrum
fast Fourier transform
błędna diagnoza
monitorowanie stanu
zwarcia międzyzwojowe
silnik synchroniczny z magnesami trwałymi
bispektrum
szybka transformata Fouriera
Opis:
The popularity of high-efficiency permanent magnet synchronous motors in drive systems has continued to grow in recent years. Therefore, also the detection of their faults is becoming a very important issue. The most common fault of this type of motor is the stator winding fault. Due to the destructive character of this failure, it is necessary to use fault diagnostic methods that facilitate damage detection in its early stages. This paper presents the effectiveness of spectral and bispectrum analysis application for the detection of stator winding faults in permanent magnet synchronous motors. The analyzed diagnostic signals are stator phase current, stator phase current envelope, and stator phase current space vector module. The proposed solution is experimentally verified during various motor operating conditions. The object of the experimental verification was a 2.5 kW permanent magnet synchronous motor, the construction of which was specially prepared to facilitate inter-turn short circuits modelling. The application of bispectrum analysis discussed so far in the literature has been limited to vibration signals and detecting mechanical damages. There are no papers in the field of motor diagnostic dealing with the bispectrum analysis for stator winding fault detection, especially based on stator phase current signal.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 2; art. no. e140556
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stator Winding Fault Detection of Permanent Magnet Synchronous Motors Based on the Short-Time Fourier Transform
Autorzy:
Pietrzak, Przemysław
Wolkiewicz, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2175935.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fault diagnosis
condition monitoring
inter-turn short circuit
permanent magnet synchronous motor
short-time Fourier transform
Opis:
In modern drive systems, the high-efficient permanent magnet synchronous motors (PMSMs) have become one of the most substantial components. Nevertheless, such machines are exposed to various types of faults. Hence, on-line condition monitoring and fault diagnosis of PMSMs have become necessary. One of the most common PMSM faults is the stator winding fault. Due to the destructive character of this failure, it is necessary to use fault diagnostic methods that allow fault detection at its early stage. The article presents the results of experimental studies obtained from fast Fourier transform (FFT) and short-time Fourier transform (STFT) analyses of the stator phase current, stator phase current envelope and stator phase current space vector module. The superiority of the proposed method over the classical approach based on the stator current analysis using FFT is highlighted. The proposed solution is experimentally verified under various motor operating conditions. The application of STFT analysis discussed so far in the literature has been limited to the fault diagnosis of induction motors and the narrow range of the analysed motor operating conditions. Moreover, there are no works in the field of motor diagnostics dealing with STFT analysis for stator windings based on the stator current envelope and the stator current space vector module.
Źródło:
Power Electronics and Drives; 2022, 7, 42; 112--133
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Template Matching Using Improved Rotations Fourier Transform Method
Autorzy:
Wijaya, Marvin Chandra
Powiązania:
https://bibliotekanauki.pl/articles/2200717.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
template matching
Fourier transform
three shear rotations
image rotation
Opis:
Template matching is a process to identify and localize a template image on an original image. Several methods are commonly used for template matching, one of which uses the Fourier transform. This study proposes a modification of the method by adding an improved rotation to the Fourier transform. Improved rotation in this study uses increment rotation and three shear methods for the template image rotation process. The three shear rotation method has the advantage of precise and noisefree rotation results, making the template matching process even more accurate. Based on the experimental results, the use of 10°angle increments has increased template matching accuracy. In addition, the use of three shear rotations can improve the accuracy of template matching by 13% without prolonging the processing time.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 4; 881--888
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Behavior of Jordanian Oil Shale during Combustion Process from the El-Lajjun Deposit
Autorzy:
Gougazeh, Mousa
Alsaqoor, Sameh
Borowski, Gabriel
Alsafasfeh, Ashraf
Hdaib, Ismail I.
Powiązania:
https://bibliotekanauki.pl/articles/2173323.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
El-Lajjun oil shale
combustion
X-ray diffraction
thermogravimetric
fourier transform infrared spectroscopy
X-ray fluorescence
Opis:
The results of X-ray diffraction, thermogravimetric and FTIR spectroscopy analyses of mineral composition indicated that the El-Lajjun oil shale is principally composed of calcite, quartz with minor amounts of kaolinite), gypsum, and apatite. The obtained oil shale ash products at 830 °C and 1030 °C are dominated by lime, quartz, anhydrite, portlandite, gehlenite, and amorphous phases. The TGA weight loss curves clearly indicate that it occurred in the temperature range from 310 to 650 °C. The decomposition of oil shale carbonates was detected above 750°C. The functional groups in the organic material of oil shale are dominated by the aliphatic hydrocarbons, the semi-ash of which had diverse structures of polycyclic aromatic hydrocarbons. The most intensive of combustion occurred in the temperature range of 400–750 °C. In this temperature range, about 75 wt.% was accounted for the total mass loss.
Źródło:
Journal of Ecological Engineering; 2022, 23, 8; 133--140
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using the MIMO method to evaluate the modal properties of the elements of a wheelset in an active experiment
Autorzy:
Milewicz, Julia
Mokrzan, Daniel
Nowakowski, Tomasz
Szymański, Grzegorz M.
Powiązania:
https://bibliotekanauki.pl/articles/24202007.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
modal analysis
FRF
fast Fourier transform
light railway vehicle
wheelset
analiza modalna
szybka transformata Fouriera
lekki pojazd szynowy
zestaw kołowy
Opis:
The study of the system composed of the inner disc and wheel rim of the 105Na type railway wheel, used in Polish Konstal streetcars, was aimed at determining the dynamic parameters of the object, such as the form and frequency of natural vibrations, and at evaluating the effectiveness of the method at given analysis settings. The experiment was conducted using triaxial piezoelectric transducers and a modal hammer with an aluminum head. A multiple-input, multiple-output (MIMO) testing approach was used because of the multiple excitation points and vibration measurements. A Fast Fourier Transform (FFT) of the measurements was performed in BK Connect software and the frequency response function (FRF) value waveforms were determined. The Rational Fraction Polynomial-Z method was used to extract modes from the frequency spectrum. In addition, the Complex Mode Indicator Function method was used, which resulted in the decomposition of the principal components of the FRF value matrix, allowing the identification of individual modes. The selection of the natural frequencies was performed on the basis of the obtained FRF and CMIF characteristics of the vibroacoustic response. Visualization of the form of the natural vibration was also performed. The result of the experiment was a set of comprehensive information on the modal properties of the studied object, which allowed to confirm the effectiveness of the selected method of analysis.
Źródło:
Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022324
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D Synthetic Aperture Imaging Method in Spectrum Domain for Low-Cost Portable Ultrasound Systems
Autorzy:
Tasinkiewicz, Jurij
Powiązania:
https://bibliotekanauki.pl/articles/31339771.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ultrasound imaging
matrix transducer
delay-and-sum
Fourier transform
synthetic aperture
Opis:
Portable, hand-held ultrasound devices capable of 3D imaging in real time are the next generation of the medical imaging apparatus adapted not only for professional medical stuff but for a wide group of less advanced users. Limited power supply capacity and the relatively small number of channels used for the ultrasound data acquisition are the most important limitations that should be taken into account when designing such devices and when developing the corresponding image reconstruction algorithms. The aim of this study was to develop a new 3D ultrasound imaging method which would take into account the above-mentioned features of the new generation of ultrasonic devices – low-cost portable general access scanners. It was based on the synthetic transmit aperture (STA) method combined with the Fourier spectrum domain (SD) acoustic data processing. The STA using a limited number of elements in transmit and receive modes for ultrasound data acquisition allowed both aforementioned constraints to be obeyed simultaneously. Moreover, the computational speed of the fast Fourier transform (FFT) algorithm utilized for the ultrasound image synthesis in the spectrum domain makes the proposed method to be more competitive compared to the conventional time domain (TD) STA method based on the delay-and-sum (DAS) technique, especially in the case of 3D imaging in real time mode. Performance of the proposed method was verified using numerical 3D acoustic data simulated in the Field II program for MATLAB and using experimental data from the custom design 3D scattering phantom collected by means of the Verasonics Vantage 256™ research ultrasound system equipped with the dedicated 1024-element 2D matrix transducer. The method proposed in this paper was about 80 times faster than its counterpart based on the time domain synthetic transmit aperture (TD-STA) approach in the numerical example of a single 3D ultrasound image synthesized from 4 partial images each containing 64 × 64 × 512 pixels. It was also shown that the acceleration of the image reconstruction was achieved at the cost of a slight deterioration in the image quality assessed by the contrast and contrast-to-noise ratio (CNR).
Źródło:
Archives of Acoustics; 2023, 48, 4; 559-572
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnosis of ITSC fault in the electrical vehicle powertrain system through signal processing analysis
Autorzy:
Ouamara, Dehbia
Boukhnifer, Moussa
Chaibet, Ahmed
Maidi, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2174472.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
induction motor
electrical vehicle
fault diagnosis
inter-turn short circuit
extended Kalman filter
spectral analysis
fast Fourier transform
short-time Fourier transform
silnik indukcyjny
pojazd elektryczny
diagnostyka uszkodzeń
zwarcie międzyzwojowe
rozszerzony filtr Kalmana
analiza spektralna
szybka transformata Fouriera
krótkoczasowa transformata Fouriera
Opis:
The three-phase induction motor is well suited for a wide range of mobile drives, specifically for electric vehicle powertrain. During the entire life cycle of the electric motor, some types of failures can occur, with stator winding failure being the most common. The impact of this failure must be considered from the incipient as it can affect the performance of the motor, especially for electrically powered vehicle application. In this paper, the intern turn short circuit of the stator winding was studied using Fast Fourier transform (FFT) and Shor-Time Fourier transform (STFT) approaches. The residuals current between the estimated currents provided by the extended Kalman filter (EKF) and the actual ones are used for fault diagnosis and identification. Through FFT, the residual spectrum is sensitive to faults and gives the extraction of inter-turn short circuit (ITSC) related frequencies in the phase winding. In addition, the FFT is used to obtain information about when and where the ITSC appears in the phase winding. Indeed, the results allow to know the faulty phase, to estimate the fault rate and the fault occurrence frequency as well as their appearance time.
Źródło:
Diagnostyka; 2023, 24, 1; art. no. 2023113
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of sway and roll excitations on sloshing loads in a KC-1 membrane LNG tank
Autorzy:
An, Se-yeol
Jeong, Hyeon-won
Kim, Ohyoung
Shim, W. Jaewoo
Powiązania:
https://bibliotekanauki.pl/articles/34600997.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
KC-1 membrane LNG tank
sloshing
sway
roll
coupled sway-roll
Fast Fourier transform (FFT)
Opis:
This study investigates the effects of sway and roll excitations on sloshing liquid loads in a tank, using Ansys Fluent software. The model considered in the study is a 1:50 scaled membrane-type tank, based on a KC-1 membrane LNG tank designed by Korea Gas Corporation (KOGAS). The volume of fluid (VOF) method is used to track the free surface inside the tank, and the standard k-ε model is applied to express the turbulent flow of the liquid. To explore the motion of the tank under excitation, a user-defined function (UDF) and a dynamic mesh technique are employed to control the external forces exerted on the tank through its motion. The results, in the form of time series data on the sloshing pressures in the tank under pure sway, roll, and coupled sway-roll, are analysed, with specific ranges for the excitation amplitudes and frequencies. We show that variations in excitation frequency and amplitude significantly influence the sloshing loads. Sloshing loads are found to intensify when the excitation frequency matches the tank’s primary natural frequency, 1.0 ω'1. Furthermore, with coupled sway-roll excitations, the sloshing loads are weakened when the sway and roll are in-phase and are intensified when these are out-of-phase. Fast Fourier transform analysis provides insights into the frequency domain, showing that the dominant frequency is 0.88 Hz and it is approximately equal to the tank’s primary natural frequency, 1.0 ω'1.
Źródło:
Polish Maritime Research; 2023, 4; 43-53
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-security image encryption by multiplexing phase encoding in domains of dual optical transforms
Autorzy:
Li, Zhihui
Gao, Bin
Pan, Xiaoou
Li, Linlin
Wang, Chenxuan
Zuo, Weizhuo
Ji, Yu
Liu, Shutian
Liu, Zhengjun
Powiązania:
https://bibliotekanauki.pl/articles/27310099.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
extended fractional Fourier transform
geometric operations
random phase encoding
Opis:
A novel optical image encryption is proposed based on multiplexing of the random phase encoding with shift and rotation operations in domains of two transforms, extended fractional Fourier transform (eFrFT) and Fresnel transform. The original image is subjected to eFrFT with the action of the random phase mask. The mask is shifted and rotated to enhance the security of this encryption method. The image obtained from eFrFT is entered into Fresnel diffraction by the use of the phase mask to obtain the final encrypted image. We plan for the phase keys to be multiplexed in order to decrease the amount of keys that need to be stored in an application. Here, the displacement, rotation angle, and wavelength in this system can be used as additional keys to improve the security and reliability of the encryption system. Numerical experiments are conducted to verify the effectiveness and security of the method. The findings demonstrate that the keys are sufficiently sensitive for high security.
Źródło:
Optica Applicata; 2023, 53, 3; 447--466
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrasound Signal Classification Based on ICA and SVM
Autorzy:
Lu, Quanbo
Wang, Meng
Li, Mei
Powiązania:
https://bibliotekanauki.pl/articles/31339863.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
independent component analysis
fast Fourier transform
support vector machine
infrasound signal
Opis:
A diagnostic technique based on independent component analysis (ICA), fast Fourier transform (FFT), and support vector machine (SVM) is suggested for effectively extracting signal features in infrasound signal monitoring. Firstly, ICA is proposed to separate the source signals of mixed infrasound sources. Secondly, FFT is used to obtain the feature vectors of infrasound signals. Finally, SVM is used to classify the extracted feature vectors. The approach integrates the advantages of ICA in signal separation and FFT to extract the feature vectors. An experiment is conducted to verify the benefits of the proposed approach. The experiment results demonstrate that the classification accuracy is above 98.52% and the run time is only 2.1 seconds. Therefore, the proposed strategy is beneficial in enhancing geophysical monitoring performance.
Źródło:
Archives of Acoustics; 2023, 48, 3; 191-199
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mycoremediation of Heavy Metals Contaminated Soil by Using Indigenous Metallotolerant Fungi
Autorzy:
Akram, Muhammad Bilal
Khan, Ibrar
Ur Rehman, Mujaddad
Sarwar, Abid
Ullah, Najeeb
ur Rahman, Shafiq
Aziz, Tariq
Alharbi, Metab
Alshammari, Abdulrahman
Alasmari, Abdullah F.
Powiązania:
https://bibliotekanauki.pl/articles/27315654.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Mycoremediation
Heavy Metals Contaminated Soil
Korangi Industrial Estate
FTIR
Fourier Transform Infrared Spectroscopy
SEM
Scanning Electron Microscope
Opis:
The present study was aimed to identify the indigenous fungal strains which could possibly be applied to the bioremediation of heavy metal-contaminated soil. The contaminated soil samples of Korangi Industrial Estate Karachi were found to have total concentration of Cu 1.044 mgL1 , and Pb 0.631 mgL–1. A total of eight indigenous strains of the fungus were isolated and screened for bioremediation capacity from heavy metals-contaminated soil. For the bioremediation of Lead (Pb) these same indigenous eight fungal strains were used for biological remediation. All the fungal isolated with enhanced bioremediation capability were through phenotypic and genotypical characterization. The topology of the phylograms established that the fungal isolates used in this study were allocated to: K1 (Penicillium notatum), K2 (Aspergillus parasiticus), K3 (Aspergillus fumigatus), K4 (Aspergillus flavus), K5 (Aspergillus terries), K6 (Fusarium solani), K7 (Penicillium chrysogenum), K8 (Aspergillus niger), K9 (Penicillium piceum) and K10 (Penicillium restrictum). Thus, K8 fungal isolate was found to be more efficient with maximum bioremediation capacity, for copper and lead removal efficiency, and selected for FTIR and SEM to find out the uptake of Cu and Pb which of the functional groups are involved, and further to detect the effects of bioleaching of both heavy metals on to the surface of K8 fungus biomass. The current study indicates that indigenous fungal isolates could be used with high potency to remediate or clean up the heavy metals-contaminated soil either by the technique of in situ or ex-situ bioremediation.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 3; 1--13
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidative Aging Characterization of Pyro-Oil Modified Binders Using Fourier Transform Infrared Spectroscopy
Autorzy:
Bhagat, Nikita Taran
Hadole, Hemantkumar Prakash
Ranadive, Mahadeo Sambhaji
Powiązania:
https://bibliotekanauki.pl/articles/2201866.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pyro-oil
aging
asphalt binder
FTIR
Fourier Transform Infrared
carbonyls
sulfoxides
HDPE processing
plastic waste
pyrolysis of plastics
Opis:
The numerous uses for plastics in various industries have led to an increase in its manufacturing on a global scale over time. The accumulation of plastic waste is a direct result of the daily rise in plastic demand. One of the effective and trending ways of reducing the impact of plastic waste on the environment is to pyrolyze it and use the oil obtained from it as fuel for power generation, heating, extraction of chemicals, or as an asphalt binder modifier. In this study, an attempt was made for the modification of asphalt binder with the oil obtained from plastic waste pyrolysis known as pyro-oil, and to analyse aging properties of the modified binder. This paper deals with the modification of VG30 binder with pyro-oil obtained from High Density Polyethylene (HDPE) plastic waste and the analysing the effect of aging on the modified binders. Pyro-oil is yielded from the pyrolysis process of HDPE at about 750°C. The modified binders were prepared by adding 1%, 2%, and 3% pyro-oil by total weight of VG30. The effect of aging for the unmodified and modified binders was analyzed using fourier transform infrared (FTIR) spectroscopy. The binders were short term aged and the changes in their chemical functionalities before and after aging were analyzed. Results of the FTIR test were used to calculate functional group indices for evaluating the aging characteristics of the modified binders. It was observed that binder chemistry is influenced by aging.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 1; 140--149
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The application of time-frequency methods of acoustic signal processing in the diagnostics of tram drive components
Autorzy:
Mokrzan, Daniel
Nowakowski, Tomasz
Szymański, Grzegorz M.
Powiązania:
https://bibliotekanauki.pl/articles/27322536.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
tram drive diagnostics
time-frequency methods
short-time fourier transform
continuous wavelet transform
acoustic pressure
cepstrum
diagnostyka napędu tramwajowego
napęd tramwajowy
metody czasowo-częstotliwościowe
transformacja falkowa
ciśnienie akustyczne
Opis:
The paper presents the course of investigations and the analysis of the possibility of applying selected methods of time frequency processing of non-stationary acoustic signals in the assessment of the technical condition of tram drive components, as well as a new combined method proposed by the authors. An experiment was performed in the form of a pass-by test of the acoustic pressure generated by a Solaris Tramino S105p tram. A comparative analysis has been carried out for an efficient case and a case with damage to the traction gear of the third bogie in the form of broken gear teeth. The recorded signal was analyzed using short-time Fourier transform (STFT) and continuous wavelet transform (CWT). It was found that the gear failure causes an increase in the sound level generated by a given bogie for frequencies within the range of characteristic frequencies of the tested device. Due to the limitations associated with the fixed window resolution in STFT and the inability to directly translate scales to frequencies in CWT, it was found that these methods can be helpful in determining suspected damage, but are too imprecise and prone to errors when the parameters of both transforms are poorly chosen. A new CWT-Cepstrum method was proposed as a solution, using the wavelet transform as a pre-filter before cepstrum signal processing. With a sampling rate of 8192 Hz, a db6 mother wavelet, and a scale range of 1:200, the new method was found to infer the occurrence of damage in an interpretation-free manner. The results were validated on an independent pair of trams of the same model with identical damage and as a reference on a pair of undamaged trams demonstrating that the method can be successfully replicated for different vehicles.
Źródło:
Archives of Transport; 2023, 68, 4; 55--75
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The heat equation on time scales
Autorzy:
Cuchta, Tom
Ferreira, Rui A. C.
Powiązania:
https://bibliotekanauki.pl/articles/29519378.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
heat equation
time scales
Fourier transform
Opis:
We present the use of a Fourier transform on time scales to solve a dynamic heat IVP. This is done by inverting a certain exponential function via contour integral. We include some specific examples and directions for further study.
Źródło:
Opuscula Mathematica; 2023, 43, 4; 475-491
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
VMD and CNN-Based Classification Model for Infrasound Signal
Autorzy:
Lu, Quanbo
Li, Mei
Powiązania:
https://bibliotekanauki.pl/articles/31339812.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
infrasound signal
variational mode decomposition
convolutional neural network
Fast Fourier Transform
Opis:
Infrasound signal classification is vital in geological hazard monitoring systems. The traditional classification approach extracts the features and classifies the infrasound events. However, due to the manual feature extraction, its classification performance is not satisfactory. To deal with this problem, this paper presents a classification model based on variational mode decomposition (VMD) and convolutional neural network (CNN). Firstly, the infrasound signal is processed by VMD to eliminate the noise. Then fast Fourier transform (FFT) is applied to convert the reconstructed signal into a frequency domain image. Finally, a CNN model is established to automatically extract the features and classify the infrasound signals. The experimental results show that the classification accuracy of the proposed classification model is higher than the other model by nearly 5%. Therefore, the proposed approach has excellent robustness under noisy environments and huge potential in geophysical monitoring.
Źródło:
Archives of Acoustics; 2023, 48, 3; 403-412
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
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