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Tytuł:
Zastosowanie algebr hiperzespolonych w przetwarzaniu sygnałów
Application of hypercomplex algebras in signal processing
Autorzy:
Błaszczyk, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/134792.pdf
Data publikacji:
2016
Wydawca:
ADVSEO
Tematy:
hypercomplex algebras
quaternion Fourier transform
octonion Fourier transform
system analysis
partial differential equations
Opis:
The subject of this paper is the application of hypercomplex algebras (in particular quaternions and octonions) in the analysis of time-invariant linear systems. We present the Cayley-Dickson construction of hypercomplex algebras and its important properties. Moreover, we formulate the concept of quaternion and octonion Fourier transform and their properties important from the signal processing point of view. We present an overview of known quaternion Fourier transform applications in the analysis of systems and partial differential equations of two variables. We also point out the direction of further work in the subject of application of the octonion Fourier transform in system analysis and analysis of partial differential equations of three variables. Such considerations are possible thanks to recently proved properties of octonion Fourier transform, which are also stated in this paper.
Źródło:
Technical Issues; 2016, 3; 13-18
2392-3954
Pojawia się w:
Technical Issues
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of sonar detection signal based on fractional Fourier transform
Autorzy:
Wang, B.
Tang, J.
Yu, F.
Zhu, Z.
Powiązania:
https://bibliotekanauki.pl/articles/259724.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
fractional Fourier transform
watermark
sonar
Opis:
Aiming at the source of underwater acoustic emission, in order to identify the enemy emission sonar source accurately. Using the digital watermarking technology and combining with the good time-frequency characteristics of fractional Fourier transform (FRFT),this paper proposes a sonar watermarking method based on fractional Fourier transform. The digital watermark embedding in the fractional Fourier transform domain and combined with the coefficient properties of the sonar signal in the fractional Fourier transform to select the appropriate watermark position. Using the different characteristics of the signals before and after embedding, an adaptive threshold was set for the watermark detection to realize the discrimination of sonar signals. The simulation results show the feasibility and has better resolution and large watermark capacity of this method, while the robustness of the watermark is better, and the detection precision is further improved.
Źródło:
Polish Maritime Research; 2018, S 2; 125-131
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amplitude demodulation of interferometric signals with a 2D Hilbert transform
Autorzy:
Wielgus, M.
Powiązania:
https://bibliotekanauki.pl/articles/115674.pdf
Data publikacji:
2011
Wydawca:
Fundacja na Rzecz Młodych Naukowców
Tematy:
Hilbert transform
image analysis
Fourier transform
demodulation
Opis:
The Hilbert transform and the analytic signal are widely known tools of 1D signal pro cessing. They are useful for many applications, such as AM-FM demodulation or edge detection. Developing the multidimensional generalization of this method is particularly important for the purposes of image processing. Unfortunately, it is not obvious how to generalize the transform, keeping its essential properties. In this paper I survey some ideas: basic approaches with spectral masks imitating 1D signum function, the spiral phase operator method and the method involving quaternionic Fourier transform. I present and compare how these algorithms are useful for the amplitude demodulation of typical interferometric images.
Źródło:
Challenges of Modern Technology; 2011, 2, 1; 8-11
2082-2863
2353-4419
Pojawia się w:
Challenges of Modern Technology
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:
Steganographic algorithm of hiding information in sound based on Fourier transform and masking
Autorzy:
Kozieł, G.
Powiązania:
https://bibliotekanauki.pl/articles/206286.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
keywords steganography
hidden communication
Fourier transform
Opis:
A new steganographicmethod based on Fourier transform is proposed. Data is attached in the frequency domain within the limits of the audible band. Masked frequencies are used to conceal information in order to make the changes inaudible for human ear. This approach allows for modification in the sound frequency band only, and does not require any additional modifications. It also allows for concealing information efficiently, minimizing the number of changes and gaining robustness with respect to popular sound transformations.
Źródło:
Control and Cybernetics; 2011, 40, 4; 1231-1247
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie transformaty Fouriera w algorytmie segmentacji standardowych obrazów koronarograficznych
Application of Fourier transform in the standard coronarography images segmentation algorithm
Autorzy:
Syrycki, M.
Mazurek, W.
Stachurska, A.
Powiązania:
https://bibliotekanauki.pl/articles/261635.pdf
Data publikacji:
2009
Wydawca:
Politechnika Wrocławska. Wydział Podstawowych Problemów Techniki. Katedra Inżynierii Biomedycznej
Tematy:
transformata Fouriera
koronografia
Fourier transform
coronography
Opis:
W pracy przedstawiono zastosowanie analizy Fouriera do efektywnej segmentacji obrazów drobnych naczyń wieńcowych w standardowych obrazach koronarograficznych.
Application of Fourier analysis for segmentation of standard coronarography images of smali coronary vessels, is discussed.
Źródło:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna; 2009, 15, 1; 58-60
1234-5563
Pojawia się w:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Filtering Property of Signal Sampling in General and Under-Sampling as a Specific Operation of Filtering Connected with Signal Shaping at the Same Time
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/226441.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal sampling
filtering
discrete-time Fourier transform
Opis:
In this paper, we show that signal sampling operation can be considered as a kind of all-pass filtering in the time domain, when the Nyquist frequency is larger or equal to the maximal frequency in the spectrum of a signal sampled. We demonstrate that this seemingly obvious observation has wide-ranging implications. They are discussed here in detail. Furthermore, we discuss also signal shaping effects that occur in the case of signal under-sampling. That is, when the Nyquist frequency is smaller than the maximal frequency in the spectrum of a signal sampled. Further, we explain the mechanism of a specific signal distortion that arises under these circumstances. We call it the signal shaping, not the signal aliasing, because of many reasons discussed throughout this paper. Mainly however because of the fact that the operation behind it, called also the signal shaping here, is not a filtering in a usual sense. And, it is shown that this kind of shaping depends upon the sampling phase. Furthermore, formulated in other words, this operation can be viewed as a one which shapes the signal and performs the low-pass filtering of it at the same time. Also, an interesting relation connecting the Fourier transform of a signal filtered with the use of an ideal low-pass filter having the cut frequency lying in the region of under-sampling with the Fourier transforms of its two under-sampled versions is derived. This relation is presented in the time domain, too.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 3; 589-594
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification of Seizure Types Using Random Forest Classifier
Autorzy:
Basri, Ashjan
Arif, Muhammad
Powiązania:
https://bibliotekanauki.pl/articles/2123290.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
EEG
fast fourier transform
seizure
random forest
Opis:
Epilepsy is one of the most common mental disorders in the world, affecting 65 million people. The prevalence in Arab countries of Epilepsy is estimated at 174 per 100,000 individuals, and in Saudi Arabia is 6.54 per 1,000 individuals. Epilepsy seizures have different types, and each patient needs to have a treatment plan according to the seizure type. Hence, accurate classification of seizure type is an essential part of diagnosing and treating epileptic patients. In this paper, features based on fast Fourier transform from EEG montages are used to classify different types of seizures. Since the distribution of classes is not uniform and the dataset suffers from severe imbalance. Various algorithms are used to under-sample the majority class and over-sample the minority classes. Random forest classifier produced classification accuracy of 96% to differentiate three types of seizures from the healthy EEG reading.
Źródło:
Advances in Science and Technology. Research Journal; 2021, 15, 3; 167--178
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sound Wave Radiation from Partially Lined Duct
Autorzy:
Tiryakioglu, Burhan
Demir, Ahmet
Powiązania:
https://bibliotekanauki.pl/articles/177899.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Wiener-Hopf
Fourier transform
duct
saddle point
Opis:
The radiation of sound waves from partially lined duct is treated by using the mode-matching method in conjunction with the Wiener-Hopf technique. The solution is obtained by modification of the Wiener-Hopf technique and involves an infinite series of unknowns which are determined from an infinite system of linear algebraic equations. Numerical solution of this system is obtained for various values of the problem parameters, whereby the effects of these parameters on the sound diffraction are studied. A perfect agreement is observed when the results of radiated field are compared numerically with a similar work existing in the literature.
Źródło:
Archives of Acoustics; 2019, 44, 2; 239-249
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Performance DIF-FFT Using Dissimilar Partitioned LUT Based Distributed Arithmetic
Autorzy:
Cheepurupalli, Kusma Kumari
Charan, Muntha
Rao, Jammu Bhaskara
Noor, Mahammad S.
Powiązania:
https://bibliotekanauki.pl/articles/2055270.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fast Fourier transform
adders
distributed arithmetic
DSP
Opis:
Real-time data processing systems utilize Digital Signal Processing (DSP) functions as the base modules. Most of the DSP functions involve the implementation of Fast Fourier Transform (FFT) to convert the signals from one domain to another domain. The major bottleneck of Decimation in frequency - Fast Fourier Transform (DIF-FFT) implementation lies in using a number of Multipliers. Distributed arithmetic (DA) is considered as one of the efficient techniques to implement DIF-FFT. In this approach, the multipliers are not used. The proposed technique exploits the very advantage of the look-up table by storing the Twiddle factors, thereby avoiding the multipliers required in the butterfly structure. DIF-FFT using Distributed Arithmetic (DIF-FFT DA) models, with different adders such as Ripple carry adder (RCA), Carry-lookahead adder (CLA), and Sklansky prefix graph adder, are proposed in this paper. The three proposed models are synthesized using Cadence 6.1 EDA tools with a 45nm CMOS technology. Compared to the traditional method, it is observed that the area is improved by 53.11%, 53.35%, and 50.15%, power is improved by 42.31%, 42.52%, and 40.39%, and delay is improved by 45.26%, 45.42%, 41.80%, respectively.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 4; 631--637
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Fourier transform as a new approach of evaluating the internal combustion engine indicator diagram
Autorzy:
Łoza, Ł.
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/244677.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
indicator diagram
Fourier transform
internal combustion engine
Opis:
In this paper, the authors present an introduction to the new method of evaluating the indicator diagram of internal combustion engine. For several years, it was observed that analyses of combustion processes have been hardly changed since they were conducted for the first time. At the moment, the diagrams are plotted more and more precisely owing to the new sensors and digital processors. Despite all of these high technical advantages, which were obviously unavailable in the past, theoretical approach for describing indicator diagram has not changed in significant way. Nowadays, the indicator diagrams are still evaluated very generally and are presented in much too idealistic way as a smooth curve of pressure changes, without any disturbances, which are being detected very easily now. Furthermore, it appears that performance improvements of the IC engines are in need of developing new methods for analysis and evaluation. The Fourier transform is a new way to look at the combustion process in the engines. It is basically a mathematical instrument for analysing different types of signals, which are transformed, from time domain into frequency domain. It enables identifying specific sinusoidal components of arbitrary signals and separates relevant ones from the noise. This allows one to see significant differences in two or more apparently similar signals and detect the crucial parts. If we treat pressure changes in time like a common signal, we can compute Fourier transform and see basic components of the diagram.
Źródło:
Journal of KONES; 2017, 24, 4; 173-180
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boehmians of type S and their Fourier transforms
Autorzy:
Bhuvaneswari, R.
Karunakaran, V.
Powiązania:
https://bibliotekanauki.pl/articles/747250.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Boehmians
spaces of type S
Fourier transform
Opis:
Function spaces of type S are introduced and investigated in the literature. They are also applied to study the Cauchy problem. In this paper we shall extend the concept of these spaces to the context of Boehmian spaces and study the Fourier transform theory on these spaces. These spaces enable us to combine the theory of Fourier transform on these function spaces as well as their dual spaces.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2010, 54, 1
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pricing correlation options: from the P. Carr and D. Madan approach to the new method based on the Fourier transform
Autorzy:
Orzechowski, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/557794.pdf
Data publikacji:
2018-03-30
Wydawca:
Uniwersytet Ekonomiczny w Poznaniu
Tematy:
Fourier transform
pricing of options
correlation options
Opis:
Pricing of options plays an important role in the financial industry. Investors knowing how to price derivative contracts quickly and accurately can beat the market. On the other hand market participants constructing their investment strategies with the use of options based on techniques that do not assure the highest computational speed and efficiency are doomed to failure. The aim of the article is to extend the existing methodology of pricing correlation options based on the Fourier transform. The article starts with a presentation of Carr and Madan’s concept (Carr & Madan, 1999). Then other methods of pricing options with the use of the Fourier transform are summarized. Finally, a new approach to pricing derivative contracts is derived and then applied to the correlation options.
Źródło:
Economics and Business Review; 2018, 4(18), 1; 16-28
2392-1641
Pojawia się w:
Economics and Business Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and geometric characterization of highly-ordered hexagonally arranged arrays of nanoporous anodic alumina
Autorzy:
Stępniowski, W. J.
Nowak-Stępniowska, A.
Michalska-Domańska, M.
Norek, M.
Czujko, T.
Bojar, Z.
Powiązania:
https://bibliotekanauki.pl/articles/779908.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
nanopores
anodization
self-organization
fast Fourier transform
Opis:
Anodic aluminum oxide (AAO) has been fabricated in the 0.3 M oxalic acid at voltage range 20-60 V and temperature range of 35-50oC. The resulting nanoporous alumina surfaces were characterized by high resolution scanning electron microscopy, and the images were quantitatively analysed by means of an innovative approach based on fast Fourier transform. The influence of operating anodization voltage and electrolyte temperature on nanopores geometry (pore diameter, interpore distance, porosity, pores density) and arrangement has been studied in details and compared to literature data and theoretical calculations. It was found that independently from the temperature, the best arrangement of the nanopores is for anodic aluminum oxide formed at voltages ranging from 40 to 50 V. Moreover, it was found that pore diameter and interpore distance increase linearly with voltage, what is in line with the literature data.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 1; 63-69
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Is there still room for increasing speed in algorithmic and high-frequency trading? The case of European options priced in the Heston Model
Autorzy:
Orzechowski, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/2147429.pdf
Data publikacji:
2019-06-03
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
European options
the Heston model
Fourier transform
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2019, 20, 1; 35-44
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete Fourier transform based pattern classifiers
Autorzy:
Hui, S.
Żak, S. H.
Powiązania:
https://bibliotekanauki.pl/articles/202074.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pattern classification
multidimensional discrete Fourier transform
DFT
Fourier coefficients
Opis:
A technique for pattern classification using the Fourier transform combined with the nearest neighbor classifier is proposed. The multidimensional fast Fourier transform (FFT) is applied to the patterns in the data base. Then the magnitudes of the Fourier coefficients are sorted in descending order and the first P coefficients with largest magnitudes are selected, where P is a design parameter. These coefficients are then used in further processing rather than the original patterns. When a noisy pattern is presented for classification, the pattern’s P Fourier coefficients with largest magnitude are extracted. The coefficients are arranged in a vector in the descending order of their magnitudes. The obtained vector is referred to as the signature vector of the corresponding pattern. Then the distance between the signature vector of the pattern to be classified and the signature vectors of the patterns in the data base are computed and the pattern to be classified is matched with a pattern in the data base whose signature vector is closest to the signature vector of the pattern being classified.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 1; 15-22
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of variants of Gabor-Wigner Transform for crossterm reduction
Autorzy:
Ajab, M.
Taj, I. A.
Khan, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/221743.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Wigner Distribution
Gabor transform
Gabor Wigner Transform
fractional Fourier transform
Opis:
Gabor Wigner Transform (GWT) is a composition of two time-frequency planes (Gabor Transform (GT) and Wigner Distribution (WD)), and hence GWT takes the advantages of both transforms (high resolution of WD and cross-terms free GT). In multi-component signal analysis where GWT fails to extract auto-components, the marriage of signal processing and image processing techniques proved their potential to extract autocomponents. The proposed algorithm maintained the resolution of auto-components. This work also shows that the Fractional Fourier Transform (FRFT) domain is a powerful tool for signal analysis. Performance analysis of modified fractional GWT reveals that it provides a solution of cross-terms of WD and blurring of GT.
Źródło:
Metrology and Measurement Systems; 2012, 19, 3; 499-508
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examining the surface of the polyamide nanocomposite using optical profilometry
Autorzy:
Majka, M.
Majka, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/134899.pdf
Data publikacji:
2014
Wydawca:
Tomasz Mariusz Majka
Tematy:
polyamide nanocomposite
montmorillonite
optical profilometry
Fourier transform image
Opis:
In this paper the results of neat polyamide 6 (PA6), processed matrix and polyamide 6 reinforced with montmorillonite 3 wt% (PA6/MMT), surface examination are presented. Examination of surface of the samples was performed using optical profilometry, which allows to measure their physical properties in non-invasive method. Based on the analysis of the radiation intensity of the reflected light from the surface the Fourier Transform was performed, to allow the analysis of images obtained in the frequency domain.
Źródło:
Journal of Education and Technical Sciences; 2014, 1, 1; 8-9
2300-7419
2392-036X
Pojawia się w:
Journal of Education and Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inversion of the Riemann-Liouville operator and its dual using wavelets
Autorzy:
Baccar, C.
Hamadi, N. B.
Herch, H.
Meherzi, F.
Powiązania:
https://bibliotekanauki.pl/articles/952838.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
inverse problem
Riemann-Liouville operator
Fourier transform
wavelets
Opis:
We define and study the generalized continuous wavelet transform associated with the Riemann-Liouville operator that we use to express the new inversion formulas of the Riemann-Liouville operator and its dual.
Źródło:
Opuscula Mathematica; 2015, 35, 6; 867-887
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The comparison on determination methods of loss distribution in credit portfolio in CreditRisk+ model
Autorzy:
Pietrzak, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/658407.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
credit risk
probability
generating function
inverse Fourier transform
Opis:
Model CreditRisk+ jest jedną z metod portfelowych służących do zarządzania ryzykiem kredytowym. W pracy omówione zostały założenia modelu, metody wyznaczenia oczekiwanych strat, jak również rozkładu straty z całego portfela kredytowego. Pierwsza numeryczna metoda stworzona przez Credit Suisse First Boston w 1997. która próbowała opisać ten model, bazowała na wzorze Panjer'a. Obecnie powstało kilka innych algorytmów umożliwiających wyznaczenie dystrybuanty straty z portfela kredytowego. Dwa z nich zostały omówione i porównane w tej pracy. Jeden algorytm bazuje na funkcji generującej prawdopodobieństwo, natomiast drugi wykorzystuje odwrotną transformatę Fouriera.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2011, 255
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast high-impedance spectroscopy method using sinc signal excitation
Autorzy:
Kowalewski, M.
Lentka, G.
Powiązania:
https://bibliotekanauki.pl/articles/220740.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
impedance spectroscopy
sinc signal
Fourier transform
impedance analyzer
Opis:
In this paper the method of fast impedance spectroscopy of technical objects with high impedance (|Zx| ≥ 1 GΩ) is evaluated by means of simulation and a practical experiment. The method is based on excitation of an object with a sinc signal and sampling the response signals proportional to current flowing through and voltage across the measured impedance. The object’s impedance spectrum is obtained with the use of continuous Fourier transform on the basis of linear approximations between samples in two acquisition sections, connected with the duration of the sinc signal. The method is first evaluated in MATLAB by means of simulation. An influence of the sinc signal duration and the number of samples on impedance modulus and argument measurement errors is explored. The method is then practically verified in a constructed laboratory impedance spectroscopy measurement system. The obtained acceleration of impedance spectroscopy in the low frequency range (below 1 Hz) and the decrease of the number of acquired samples enable to recommend the worked out method for implementation in portable impedance analyzers destined for operation in the field.
Źródło:
Metrology and Measurement Systems; 2013, 20, 4; 645-654
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active Cancellation of the Tonal Component of Sound Using a Discrete Fourier Transform of Variable Length
Autorzy:
Łuczyński, Michał
Dobrucki, Andrzej
Brachmański, Stefan
Powiązania:
https://bibliotekanauki.pl/articles/2097702.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
active noise control
tonal signal
Discrete Fourier Transform
Opis:
The paper presents a method of eliminating the tonal component of an acoustic signal. The tonal component is approximated by a sinusoidal signal of a given amplitude and frequency. As the parameters of this component: amplitude, frequency and initial phase may be variable, it is important to detect these parameters in subsequent analysis time intervals (frames). If the detection of the parameters is correct, the elimination consists in adding a sinusoidal component with the detected amplitude and frequency to the signal, but the phase shifted by 180 degrees. The accuracy of the reduction depends on the accuracy of parameters detection and their changes. Detection takes place using the Discrete Fourier Transform, whose length is changed to match the spectrum resolution to the signal frequency. The operation for various methods of synthesis of the compensating signal as well as various window functions were checked. An elimination simulation was performed to analyze the effectiveness of the reduction. The result of the paper is the assessment of the method in narrowband active noise control systems. The method was tested by simulation and then experimentally with real acoustic signals. The level of reduction was from 6.9 to 31.5 dB.
Źródło:
Archives of Acoustics; 2021, 46, 4; 579-589
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On implementation of FFT processor in XILINX FPGA using high-level synthesis
Autorzy:
Smyk, Robert
Czyżak, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/377926.pdf
Data publikacji:
2020
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
Fast Fourier Transform Processor
FPGA
high-level synthesis
Opis:
The paper presents results of the high level synthesis of an 1024-point radix-2 FFT processors in Xilinx Vivado FPGA environment. The use of various directives controlling the synthesis process is examined. The results indicate that using the proper set of directives the latency of the processor can be reduced by 95% from about 35k for the default parameters to 1.5k cycles after optimizations.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2020, 104; 17-33
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Construction of nonuniform periodic wavelet frames on non-Archimedean fields
Autorzy:
Ahmad, Owais
Powiązania:
https://bibliotekanauki.pl/articles/2078967.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Nonuniform frame
wavelet mask
scaling function
Fourier transform
Opis:
In real life applications not all signals are obtained by uniform shifts; so there is a natural question regarding analysis and decompositions of these types of signals by a stable mathematical tool. Gabardo and Nashed, and Gabardo and Yu filled this gap by the concept of nonuniform multiresolution analysis and nonuniform wavelets based on the theory of spectral pairs for which the associated translation set \(\Lambda= \{0,r/N\}+2\mathbb{Z}\) is no longer a discrete subgroup of \(\mathbb{R}\) but a spectrum associated with a certain one-dimensional spectral pair and the associated dilation is an even positive integer related to the given spectral pair. In this paper, we introduce a notion of nonuniform periodic wavelet frame on non-Archimedean field. Using the Fourier transform technique and the unitary extension principle, we propose an approach for the construction of nonuniform periodic wavelet frames on non-Archimedean fields.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2020, 74, 2; 1-17
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of random sums of random variables in insurance
Autorzy:
Wlaź, P.
Powiązania:
https://bibliotekanauki.pl/articles/102826.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
random sum
fast Fourier transform
shifted gamma distribution
Opis:
The paper deals with approximations of random sums. By random sum we mean a sum of random number of independent and identically distributed random variables. Distribution of this sum is called a compound distribution. The model is especially important in non-life insurance. There are many methods for approximating compound distributions, one of the most popular one is approximation with shifted gamma distribution. In this work we show an alternative way – using kernel density, Fast Fourier Transform and numerical optimization methods – for finding shifted gamma approximations and show results suggesting its superiority over classical method.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 23; 88-93
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 225

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