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Wyszukujesz frazę "VMD" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
MHD free convective heat and mass transfer flow from a vertical porous surface with variable thermal conductivity, variable mass diffusivity and thermal diffusion including viscous dissipation and chemical reaction
Autorzy:
Phakirappa, J.
Priyanka, S.
Veena, P. H.
Pravin, V. K.
Powiązania:
https://bibliotekanauki.pl/articles/2174212.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
lepkość
reakcja chemiczna
magnetohydrodynamika
MHD
VTD
VMD
viscous dissipation
chemical reaction
Opis:
analysis is carried out to study chemically reactive, viscous dissipative effects of an incompressible and electrically conducting fluid with MHD free convection adjacent to a vertical surface with variable thermal conductivity (VTD) and variable mass diffusivity (VMD). An approximate numerical solution for the steady laminar boundary layer flow over a wall of the surface in the presence of species concentration and thermal mass diffusion has been studied. Using numerical techniques the governing boundary layer equations are solved to get the exact solution. Numerical calculations are carried out for different values of dimensionless parameters. The results are exhibited through various graphs and it is observed from the analysis of the results that the velocity field is appreciably influenced by the magnetic effect, porous effect, chemical reaction and buoyancy ratio between the species and thermal diffusion at the wall of the surface.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 3; 127--136
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on transformer fault diagnosis technology of VMD local signal de-noising based on kurtosis - approximate entropy
Autorzy:
Chen, Dingke
Mao, Changbin
Qin, Bin
Powiązania:
https://bibliotekanauki.pl/articles/328591.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
transformer
kurtosis
approximate entropy
variational mode decomposition
VMD
transformator
diagnostyka uszkodzeń
kurtoza
entropia
niezawodność
Opis:
With the needs of social development, the scale of power equipment continues to expand. Among them, the transformer, as the core equipment in the power system, plays a key role in the safe and stable operation of the power system. However, in the field where the field strength is too high, partial breakdown of insulating media, that is the partial discharge occurs, which brings certain threats and damage to the safe operation of the power system. Therefore, this article uses the kurtosis-approximate entropy variational mode decomposition (VMD) partial discharge signal denoising method is used to preprocess the UHF partial discharge signal, through the simulation analysis and the result comparison, the feasibility of the method for denoising the partial signal of the transformer is clarified, designed to improve the safety and reliability of transformer operation.
Źródło:
Diagnostyka; 2020, 21, 1; 81-87
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on communication emitter identification based on semi-supervised dimensionality reduction in complex electromagnetic environment
Autorzy:
Ge, Wei
Qi, Lin
Tong, Lin
Zhu, Jun
Zhang, Jing
Zhao, Dongyang
Li, Ke
Powiązania:
https://bibliotekanauki.pl/articles/27311449.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
communication emitter identification
feature extraction
dimensionality reduction
VMD
ESDA
variational mode decomposition
exponential semi-supervised discriminant analysis
identyfikacja emitera komunikacyjnego
ekstrakcja cech
redukcja wymiarowości
rozkład w trybie wariacyjnym
analiza dyskryminacyjna wykładnicza półnadzorowana
Opis:
The individual identification of communication emitters is a process of identifying different emitters based on the radio frequency fingerprint features extracted from the received signals. Due to the inherent non-linearity of the emitter power amplifier, the fingerprints provide distinguishing features for emitter identification. In this study, approximate entropy is introduced into variational mode decomposition, whose features performed in each mode which is decomposed from the reconstructed signal are extracted while the local minimum removal method is used to filter out the noise mode to improve SNR. We proposed a semi-supervised dimensionality reduction method named exponential semi-supervised discriminant analysis in order to reduce the high-dimensional feature vectors of the signals, and LightGBM is applied to build a classifier for communication emitter identification. The experimental results show that the method performs better than the state-of-the-art individual communication emitter identification technology for the steady signal data set of radio stations with the same plant, batch and model.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 4; art. no. e145766
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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