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Wyświetlanie 1-15 z 44
Tytuł:
A hybrid approach for fault diagnosis of spur gears using Hu invariant moments and artificial neural networks
Autorzy:
Rex, F. Michael Thomas
Andrews, A.
Krishnakumari, A.
Hariharasakthisudhan, P.
Powiązania:
https://bibliotekanauki.pl/articles/220768.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gear fault
Ahao-Atlas-Marks
time-frequency domain features
Hu invariant moments
ANN
Opis:
Achieving a reliable fault diagnosis for gears under variable operating conditions is a pressing need of industries to ensure productivity by averting unwanted breakdowns. In the present work, a hybrid approach is proposed by integrating Hu invariant moments and an artificial neural network for explicit extraction and classification of gear faults using time-frequency transforms. The Zhao-Atlas-Marks transform is used to convert the raw vibrations signals from the gears into time-frequency distributions. The proposed method is applied to a single-stage spur gearbox with faults created using electric discharge machining in laboratory conditions. The results show the effectiveness of the proposed methodology in classifying the faults in gears with high accuracy.
Źródło:
Metrology and Measurement Systems; 2020, 27, 3; 451-464
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An identification procedure of electromagnetic parameters for an induction motor equivalent circuit including rotor deep bar effect
Autorzy:
Rolek, J.
Utrata, G.
Powiązania:
https://bibliotekanauki.pl/articles/141612.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
induction motors
equivalent circuits
parameter identification
frequency-domain analysis
genetic algorithms
Opis:
The paper presents an identification procedure of electromagnetic parameters for an induction motor equivalent circuit including rotor deep bar effect. The presented procedure employs information obtained from measurement realised under the load curve test, described in the standard PN-EN 60034-28: 2013. In the article, the selected impedance frequency characteristics of the tested induction machines derived from measurement have been compared with the corresponding characteristics calculated with the use of the adopted equivalent circuit with electromagnetic parameters determined according to the presented procedure. Furthermore, the characteristics computed on the basis of the classical machine T-type equivalent circuit, whose electromagnetic parameters had been identified in line with the chosen methodologies reported in the standards PN-EN 60034-28: 2013 and IEEE Std 112TM-2004, have been included in the comparative analysis as well. Additional verification of correctness of identified electromagnetic parameters has been realised through comparison of the steady-state power factor-slip and torque-slip characteristics determined experimentally and through the machine operation simulations carried out with the use of the considered equivalent circuits. The studies concerning induction motors with two types of rotor construction – a conventional single cage rotor and a solid rotor manufactured from magnetic material – have been presented in the paper.
Źródło:
Archives of Electrical Engineering; 2018, 67, 2; 279--291
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Improved Method of Permutation Correction in Convolutive Blind Source Separation
Autorzy:
Wang, L.
Ding, H.
Yin, F.
Powiązania:
https://bibliotekanauki.pl/articles/177954.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
blind source separation
cocktail party
convolutive mixing
frequency domain
permutation problem
Opis:
This paper proposes an improved method of solving the permutation problem inherent in frequency-domain of convolutive blind source separation (BSS). It combines a novel inter-frequency dependence measure: the power ratio of separated signals, and a simple but effective bin-wise permutation alignment scheme. The proposed method is easy to implement and surpasses the conventional ones. Simulations have shown that it can provide an almost ideal solution of the permutation problem for a case where two or three sources were mixed in a room with a reverberation time of 130 ms.
Źródło:
Archives of Acoustics; 2010, 35, 4; 493-504
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza metod pomiarów zaburzeń przewodzonych EMC z wykorzystaniem pakietu Mathematica
Analysis of EMC measuring methods for conducted interference with use of Mathematica package
Autorzy:
Duzinkiewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/157946.pdf
Data publikacji:
2012
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pomiary w dziedzinie czasu i częstotliwości
EMC
zaburzenia przewodzone
transformata Fouriera
okno czasowe
measurements in time and frequency domain
conducted interferences
Fourier transform
time window
Opis:
W artykule przedstawiono pozanormatywne metody pomiarów zaburzeń przewodzonych EMC na przykładzie zasilacza impulsowego AC/DC. Wykonano analizę porównawczą znormalizowanych pomiarów kompatybilności elektromagnetycznej zaburzeń przewodzonych wykonywanych specjalizowanym odbiornikiem pomiarowym EMC z badaniami pozanormatywnymi wykonanymi w dziedzinie czasu za pomocą oscyloskopu cyfrowego. Do obliczeń numerycznych i wizualizacji wyników pomiarów wykorzystano pakiet Wolfram Mathematica 8. Przeprowadzona analiza wykazała porównywalne wyniki pomiarów obu metod.
This paper presents the comparative analysis of measurements of conducted interferences taken with an EMI test receiver [5] (Fig. 1) according to norm [4] (PN-EN 55014) and non-normative measurements made by means of a digital oscilloscope (Fig. 2) in time domain. The investigations were carried out on an AC/DC supplying converter, commonly used in a low power chip TNY266 [6] (Fig. 4). Section 2 describes the measurement tests performed with the digital oscilloscope. Section 3 presents analytical transformations of signals from the time domain (Fig. 5) into the frequency domain (Fig. 6). Section 4 deals with a mathematical model of transforming [8] the sinusoidal signal with a third harmonic (Fig. 7) to the form of the frequency spectrum by means of a time window (Fig. 9). Use of time windows in real signal transformations is shown in Section 5 (Fig. 10). The signal frequency spectrum in electromagnetic compatibility research [1, 2] determines one of the most important ways of describing the level of disturbances emitted by electric and electronic equipment. Therefore the analysis results are shown on the same diagram (Fig. 11) in the frequency domain: the signal frequency spectrum of interferences measured with the EMI test receiver as well as the signal frequency spectrum obtained analytically. Numerical calculations and visualization of the measurement results were made with Wolfram Mathematic 8 packet. The analysis results show that there are slight differences between those two methods.
Źródło:
Pomiary Automatyka Kontrola; 2012, R. 58, nr 9, 9; 801-804
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and simulation modeling of programmable circuits using digital potentiometers
Autorzy:
Pandiev, I. M
Powiązania:
https://bibliotekanauki.pl/articles/398071.pdf
Data publikacji:
2014
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
mixed analogue digital integrated circuits
digital potentiometer
programmable circuits
frequency domain analysis
behavioral modelling
circuit simulation
analogowo-cyfrowe układy scalone
potencjometr cyfrowy
układy programowalne
analiza dziedziny częstotliwości
modelowanie behawioralne
symulacja obwodu
Opis:
In this paper an object of analysis and simulation modeling are the basic programmable circuits using CMOS digital potentiometers or Resistive Digital-to-Analog Converters (RDACs). Based on the analysis and principle of operation an improved SPICE-based behavioral model for RDAC potentiometers is created. The model accurately reflects resolution (wiper steps), nominal end-to-end resistance, wiper resistance, linear and nonlinear increment/decrement of the wiper, common-mode leakage current, operating bandwidth, analog crosstalk, temperature coefficients and noise effects. Model parameters are extracted for the dual RDAC potentiometer AD5235 from Analog Devices as an example. The workability of the proposed simulation model is verified by simulation modeling and experimental testing of sample electronic circuits.
Źródło:
International Journal of Microelectronics and Computer Science; 2014, 5, 4; 127-135
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the electromagnetic response of complex dispersive material with the single-step wideband finite element method
Autorzy:
Butryło, B.
Powiązania:
https://bibliotekanauki.pl/articles/141234.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
propagation of electromagnetic pulse
dielectric dispersion
frequency selective materials
broadband time-domain simulation
finite element time-domain method
Opis:
The paper describes the formulation and implementation of the broadband finite element time domain algorithm. The presented formalism is valid to analysis of electromagnetic phenomena in linear, frequency selective materials. The complex profile of permittivity of materials is approximated using a set of the Lorentz resonance models. The solution of the integro-differential second order equation is obtained using a singlestep integration scheme and a recursive convolution algorithm. The discussed formulation enables to adopt the structure of the narrowband part as well as the phase of calculation of the convolution equations for the subsequent components. The properties of the algorithm are validated using a finite difference broadband algorithm.
Źródło:
Archives of Electrical Engineering; 2013, 62, 1; 111-122
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of modelling and simulation to evaluate the theta method used in diagnostics of automotive shock absorbers
Autorzy:
Lozia, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/2124764.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Tematy:
frequency domain analysis
quarter car model
theta method
suspension damping
automotive diagnostics
Opis:
The dynamic properties of the car's suspension largely depend on the damping that results from the state of the shock absorbers. Their technical condition is essential for vehicle occupants’ comfort and traffic safety. It changes with the time and intensity of use of the vehicle. Therefore, adequate methods of non-destructive (diagnostic) testing of suspension damping have been sought for many years. The on-vehicle tests are particularly useful thanks to their low cost and short test duration time. The newest method is the ‘theta’ method which is the subject of the presented article. Notation ‘theta’ usually means relative damping (damping ratio) in the vibrating system. The paper asses four variants of the method. Two versions come from modal analysis and are also known as the ‘peak-picking method’ or ‘half-power method’. Two other versions are described in cited patent documentations. Three linear ‘quarter car' models with their description in the frequency domain were used to assess mentioned variants of the ‘theta’ method. Calculations were made for two typical datasets corresponding to the front and rear suspension system of a medium-class motor car. This provided grounds for general qualitative and (within a limited scope) quantitative assessment of the usefulness of individual variants of the method under analysis and for comparisons between them. The paper is to help in choosing the variant of the ‘theta’ method that would most likely find the application and that might be recommended to manufacturers and would-be purchasers of diagnostic suspension testers. The author has also highlighted the importance of possible further research.
Źródło:
Archiwum Motoryzacji; 2022, 96, 2; 5--30
1234-754X
2084-476X
Pojawia się w:
Archiwum Motoryzacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Software-Defined Radio for Rayleigh and Raman Scattering Measurement in Optical Fibers
Autorzy:
Shatarah, I. S. M.
Więcek, B.
Powiązania:
https://bibliotekanauki.pl/articles/114286.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
Rayleigh and Raman scattering
synchronous detection
silica optical fiber
optical frequency domain reflectometry
Opis:
A laboratory system for measuring the Raman scattering light in optical fiber is presented. The system is equipped with the developed driver for 5 mW/1550 nm laser diode, optical circulator, WDM filters to separate Rayleigh and Raman scattered light and InGaAs cooled photodiode to detect the weak scattered radiation. Instead of using expensive network analyzer we propose to use Software-Defined Radio, which ensures the necessary sensitivity and selectivity of detected signals. The preliminary results are presented for about 3 km – length single mode silica optical fiber.
Źródło:
Measurement Automation Monitoring; 2018, 64, 4; 112-115
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applications and Comparison of Continuous Wavelet Transforms on Analysis of A-wave Impulse Noise
Autorzy:
Qin, J.
Sun, P.
Powiązania:
https://bibliotekanauki.pl/articles/177117.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
continuous wavelet transform (CWT)
impulse noise signal processing
time-frequency domain
temporal and spectral resolutions
noise-induced hearing loss
A-wave impulse noise
Opis:
Noise induced hearing loss (NIHL) is a serious occupational related health problem worldwide. The A-wave impulse noise could cause severe hearing loss, and characteristics of such kind of impulse noise in the joint time-frequency (T-F) domain are critical for evaluation of auditory hazard level. This study focuses on the analysis of A-wave impulse noise in the T-F domain using continual wavelet transforms. Three different wavelets, referring to Morlet, Mexican hat, and Meyer wavelets, were investigated and compared based on theoretical analysis and applications to experimental generated A-wave impulse noise signals. The underlying theory of continuous wavelet transform was given and the temporal and spectral resolutions were theoretically analyzed. The main results showed that the Mexican hat wavelet demonstrated significant advantages over the Morlet and Meyer wavelets for the characterization and analysis of the A-wave impulse noise. The results of this study provide useful information for applying wavelet transform on signal processing of the A-wave impulse noise.
Źródło:
Archives of Acoustics; 2015, 40, 4; 503-512
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of a linear dynamic process model using the frequency approach and a non-quadratic measure of the model error
Autorzy:
Janiszowski, K. B.
Powiązania:
https://bibliotekanauki.pl/articles/330395.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
approximation method
frequency domain
nonquadratic criterion
recursive algorithm
metoda aproksymacji
dziedzina częstotliwości
algorytm rekurencyjny
Opis:
The paper presents a novel approach to approximation of a linear transfer function model, based on dynamic properties represented by a frequency response, e.g., determined as a result of discrete-time identification. The approximation is derived for minimization of a non-quadratic performance index. This index can be determined as an exponent or absolute norm of an error. Two algorithms for determination of the approximation coefficients are considered, a batch processing one and a recursive scheme, based on the well-known on-line identification algorithm. The proposed approach is not sensitive to local outliers present in the original frequency response. Application of the approach and its features are presented on examples of two simple dynamic systems.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 1; 99-109
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automatyczna klasyfikacja instrumentów szarpanych w multimedialnych bazach danych
Automatic classification of string instruments in multimedia databases
Autorzy:
Cudny, W.
Tyburek, K.
Kosiński, W.
Powiązania:
https://bibliotekanauki.pl/articles/152592.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
widmo sygnału
deskryptory
pizzicato
chordofony
MPEG-7 standard
audio signals
frequency domain
descriptors
classification
chordophones
Opis:
Klasyfikacją i agregacją danych multimedialnych zajmuje się standard MPEG-7, który dostarcza szereg podstawowych deskryptorów opisujących dźwięk. Wzorując się na istniejącym standardzie MPEG-7 stworzono nowe deskryptory rozpoznające konkretne instrumenty muzyczne. Głównym zadaniem postawionym w badaniach jest takie zdefiniowanie deskryptorów w przestrzeni widmowej, które w połączeniu z określonymi algorytmami przeszukiwań pozwolą na prawidłową interpretację źródła dźwięku z artykulacją piccicato. Do badań wybrano grupę strunowych instrumentów muzycznych znaną pod nazwą chordofonów.
Classification and agregation of multimedia data used, for example in production processes of TV and radio stations is made by the use of MPEG-7 staandard. Searching process can be speed up if an appropriate labeling (indexing) of signals is used. The paper concerns determination of a set of descriptors in the spectrum domain which can allow to classify pizzicato sound signals generated by 8 different chordophone instruments being a subset of strings.
Źródło:
Pomiary Automatyka Kontrola; 2007, R. 53, nr 5, 5; 33-35
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binaural speech segregation system on single board computer
Autorzy:
Usagawa, Tsuyoshi
Irwansyah, Irwansyah
Powiązania:
https://bibliotekanauki.pl/articles/950427.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
frequency domain binaural model
single-board computer
hearing assistance
open-source software
komputer jednopłytkowy
wsparcie słuchu
oprogramowanie otwarte
Opis:
A pocket-size binaural speech segregation system has been developed and assembled with available consumer hardware. It can enhance a target speech in a certain direction while attenuating interfering sounds from other directions. This system is based on the frequency domain binaural model (FDBM) and it segregates multiple speeches based on the directivity. This real-time system is implemented on a low-cost single board computer which might be used as a hearing assistance device. Performance of the system is evaluated in a normal laboratory room as well as anechoic chamber. Even in a room with reverberation, the system works well and show the almost same performance obtained in anechoic chamber.
Źródło:
Vibrations in Physical Systems; 2019, 30, 1; 1-9
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combination of criteria for controller parameterisation in the time and frequency domain by simulation-based optimisation
Autorzy:
Hipp, K.
Uhrig, M.
Hellmich, A.
Schlegel, H.
Neugebauer, R.
Powiązania:
https://bibliotekanauki.pl/articles/99661.pdf
Data publikacji:
2016
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
simulation based optimisation
optimisation criteria
controller parameterisation
frequency domain
time domain
Opis:
The position controller cascade is widely used in standard industrial controllers. Its controller parameterisation is commonly performed by either applying basic tuning rules or by carrying out not comprehensible design automatisms.In this paper an alternative approach to parameterise the cascade in one step is presented. It bases on established methods within the field of optimisation research specifically the so-called simulation-based optimisation (SBO), which can also handle non-linear models and various constrains. Own research showed, that criteria in the time domain as well as in the frequency domain are suitable optimisation criteria. However, both types have individual advantages and disadvantages. Therefore, in this research, selected representatives from both types were combined as new multi-objective optimisation criteria and investigated according to their performance. Investigations were performed for a test rig model (third order transfer function plus dead time and friction).The paper presents fundamentals of the SBO and a description of the optimisation criteria, obtained results as well as their verification on the test rig. Also, the derived controller parameterisations are compared to the integrated tuning automatism.
Źródło:
Journal of Machine Engineering; 2016, 16, 4; 70-81
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Common path optical coherence tomography with electronic feedback for improved sensitivity
Autorzy:
Alsnaie, Khalid
Powiązania:
https://bibliotekanauki.pl/articles/27310102.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical coherence tomography
frequency domain
OCT
medical imaging
partially coherent interferometers
B-scan
Opis:
Optical coherence tomography (OCT) imaging has become a useful tool in medical diagnosis over the past 25 years, because of its ability to visualize intracellular structures at high resolution. The main objective of this work is to add electronic feedback to the optical coherence tomography setup to increase its sensitivity. Noise added to the measured interferogram obscures some details of examined tissue layered structure. Adjusting signal power level in such a way to improve signal-to-noise ratio can help to enhance image quality. Electronic feedback is added to enhance system sensitivity. A logarithmic amplifier is included in the OCT setup to automatically adapt signal level. Moreover, the resolution of the optical spectrum analyzer is controlled according to the farthest layer detected in the A-scan. These techniques are tested showing an improvement in obtained image of a human nail.
Źródło:
Optica Applicata; 2023, 53, 3; 495--504
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Open-Ended Coax and TDR sensors for the measurement of soil dielectric permittivity in microwave frequencies
Autorzy:
Skierucha, W.
Walczak, R.
Wilczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/24912.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
microwave frequency
soil permittivity
measurement
soil
dielectrical permittivity
time domain reflectometry
Źródło:
International Agrophysics; 2004, 18, 4
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 44

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