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Wyszukujesz frazę "Fourier transform" wg kryterium: Temat


Tytuł:
Construction of a Fourier transform based on Haar measure in structure (Rn, +, T)
Autorzy:
Żukowicz, M
Powiązania:
https://bibliotekanauki.pl/articles/359240.pdf
Data publikacji:
2014
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
Fourier transform
Haar measure
Haar integral
compact-open topology
characters of topological group
group of characters
Opis:
An important aspects of learning are the theoretical elements of mathematics and the methods of obtaining the function or designbecause it allows for further development of the issues and the ability to apply this problem in practice. The Fourier transform is very useful in science and technology. The article shows how and in what structures is possible to use the Fourier transform in the set Rn. The article describes the project of compact-open topology, which is essential to the construction of the Haar measure and integral. It was also described the concept of the nature of a locally compact topological group, because a group of characters is also essential to the construction of the Fourier transform and inverse Fourier transform. It has been proven that a group of characters is a locally compact topological group, which allows the introduction of the Haar measure. It has given an example application of the theory of Haar integral when calculating the Fourier transform for some of the electronics.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2014, 39 (111); 181-184
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Composition of wavelet and Fourier transforms
Autorzy:
Ziółko, Mariusz
Witkowski, Marcin
Gałka, Jakub
Powiązania:
https://bibliotekanauki.pl/articles/747314.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
wavelet transform, Fourier transform, numerical methods, sparse systems
Transformacja falkowa, transformacja Fouriera, metody numeryczne, systemy rzadkie
Opis:
W pracy przedstawione są podstawowe własności szeregowego złożenia dwóch transformacji: falkowej i Fouriera. Uzyskano dwa rodzaje transformacji ponieważ transformacje falkowe i Fouriera nie są przemienne. Przedstawione są konsekwencje zjawiska zwanego "przestępstwem falkowym". Zastosowanie falek ze zwartymi nośnikami w dziedzinie częstotliwości (np. falki Meyera) prowadzi do reprezentacji sygnałów w postaci macierzy rzadkich. Sygnały mowy zostały użyte do przetestowania przedstawionych transformacji.
The paper presents the basic properties of the serial composition of two transformations: wavelet and Fourier. Two types of transformations were obtained because wavelet and Fourier transformations do not commute. The consequences of a phenomenon known as a "wavelet crime" are presented. Using wavelets with compact support in the frequency domain (e.g. Meyer wavelets) leads to the representation of signals as sparse matrices. Speech signals were used to test the presented transforms.
Źródło:
Mathematica Applicanda; 2018, 46, 1
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tool wear condition monitoring in milling process based on data fusion enhanced long short-term memory network under different cutting conditions
Autorzy:
Zheng, Guoxiao
Sun, Weifang
Zhang, Hao
Zhou, Yuqing
Gao, Chen
Powiązania:
https://bibliotekanauki.pl/articles/2038054.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
tool wear condition monitoring
empirical mode decomposition
variational mode decomposition
fourier synchro squeezed transform
neighborhood component analysis
long short-term memory network
Opis:
Tool wear condition monitoring (TCM) is essential for milling process to ensure the machining quality, and the long short-term memory network (LSTM) is a good choice for predicting tool wear value. However, the robustness of LSTM- based method is poor when cutting condition changes. A novel method based on data fusion enhanced LSTM is proposed to estimate tool wear value under different cutting conditions. Firstly, vibration time series signal collected from milling process are transformed to feature space through empirical mode decomposition, variational mode decomposition and fourier synchro squeezed transform. And then few feature series are selected by neighborhood component analysis to reduce dimension of the signal features. Finally, these selected feature series are input to train the bidirectional LSTM network and estimate tool wear value. Applications of the proposed method to milling TCM experiments demonstrate it outperforms significantly SVR- based and RNN- based methods under different cutting conditions.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 4; 612-618
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
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:
Time invariant property of weighted circular convolution and its application to continuous wavelet transform
Autorzy:
Yi, Hua
Ru, Yu-Le
Dai, Yin-Yun
Powiązania:
https://bibliotekanauki.pl/articles/2086853.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
continuous wavelet transform
linear convolution
weighted circular convolution
generalized discrete Fourier transform
ciągła transformata falkowa
splot liniowy
splot kołowy ważony
transformata Fouriera uogólniona dyskretna
Opis:
Time invariant linear operators are the building blocks of signal processing. Weighted circular convolution and signal processing framework in a generalized Fourier domain are introduced by Jorge Martinez. In this paper, we prove that under this new signal processing framework, weighted circular convolution also has a generalized time invariant property. We also give an application of this property to algorithm of continuous wavelet transform (CWT). Specifically, we have previously studied the algorithm of CWT based on generalized Fourier transform with parameter 1. In this paper, we prove that the parameter can take any complex number. Numerical experiments are presented to further demonstrate our analyses.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 4; e137726, 1--9
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A radial version of the Kontorovich-Lebedev transform in the unit ball
Autorzy:
Yakubovich, S. B.
Vieira, N.
Powiązania:
https://bibliotekanauki.pl/articles/255671.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Kontorovich-Lebedev transform
modified Bessel function
index transforms
Fourier integrals
Opis:
In this paper we introduce a radial version of the Kontorovich-Lebedev transform in the unit ball. Mapping properties and an inversion formula are proved in Lp.
Źródło:
Opuscula Mathematica; 2011, 31, 1; 137-146
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beurlings theorems and inversion formulas for certain index transforms
Autorzy:
Yakubovich, S. B.
Powiązania:
https://bibliotekanauki.pl/articles/255306.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Beurling theorem
Kontorovich-Lebedev transform
Lebedev-Skalskaya transforms
Fourier transform
Laplace transform
modified Bessel functions
uncertainty principle
Nicholson function
Opis:
The familiar Beurling theorem (an uncertainty principle), which is known for the Fourier transform pairs, has recently been proved by the author for the Kontorovich-Lebedev transform. In this paper analogs of the Beurling theorem are established for certain index transforms with respect to a parameter of the modified Bessel functions. In particular, we treat the generalized Lebedev-Skalskaya transforms, the Lebedev type transforms involving products of the Alacdoriald functions of different arguments and an index transform with the Nicholson kernel function. We also find inversion formulas for the Lebedev-Skalskaya operators of an arbitrary index and the Nicholson kernel transform.
Źródło:
Opuscula Mathematica; 2009, 29, 1; 93-110
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image encryption algorithm based on rear-mounted phase mask and random decomposition
Autorzy:
Yadav, Shivani
Singh, Hukum
Powiązania:
https://bibliotekanauki.pl/articles/2086758.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fractional Fourier transform
random decomposition
rear-mounted phase mask
SVD
singular value decomposition
Opis:
To escalate the image encryption a new method has been devised which includes double random phase encoding (DRPE) using rear phase masking and random decomposition (RD) technique stranded on fractional Fourier transform. Here, asymmetric cryptographic system is developed in fractional Fourier transform (FrFT) mode using two random phase masks (RPM) and a rear mounted phase mask. In the projected scheme a colored image is decomposed into R, G and B channels. The amplitude of each channel is normalized, phase encoded and modulated using RPM. The modulated R, G and B channels of the colored image are individually transformed using FrFT to produce corresponding encrypted image. The proposed scheme is authorized on grayscale image also. The norm behind the development of the suggested scheme has been elaborated by carrying out cryptanalysis on system based on the RD. The method helps in escalations of the protection of double random phase encoding by cumulating the key length and the parameter amount, so that it vigorously can be used against various attacks. The forte of the suggested cryptographic system was verified using simulations with MATLAB 7.9.0 (R2008a). The efficiency of the suggested scheme includes the analysis using singular value decomposition (SVD), histogram and correlation coefficient.
Źródło:
Optica Applicata; 2022, 52, 2; 195--212
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
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
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:
Introduction to Fourier analysis using IT tools of Laboratory of Technical Aids of Teaching IF UJ
Autorzy:
Wietecha, Tomasz
Kurzydło, Piotr M.
Bogacz, Bogdan F.
Powiązania:
https://bibliotekanauki.pl/articles/2014239.pdf
Data publikacji:
2021
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
Fourier transform
FFT
didactics
motoric aspects of approximation
coach program
transformacja Fouriera
dydaktyka
motoryczne aspekty aproksymacji
program trenerski
Opis:
The general aim of this article is to present didactic aspects of familiarizing students with the Fourier analysis. This didactic process issues through the use of IT tools of Laboratory of Technical Aids of Teaching is discussed. There are four separate computer stations, differing in software, where students learn step by step: composing signals from single harmonics, visualization through images of rotating vectors of harmonic signal composition, operation of a virtual generator of a given number of harmonics and elements of the CMA Coach system in the context of signal analysis. The applied didactic methods are aimed at students of biophysics for whom the Fourier analysis is of practical importance.
Źródło:
Science, Technology and Innovation; 2021, 12, 1; 10-15
2544-9125
Pojawia się w:
Science, Technology and Innovation
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:
Comparative Study on the Frictional Sound Properties of Woven Fabrics
Badanie porównawcze właściwości dźwięku tarcia tkanin
Autorzy:
Wang, P.-N.
Ho, M.-H.
Cheng, K.-B.
Murray, R.
Lin, C.-H.
Powiązania:
https://bibliotekanauki.pl/articles/233866.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
KES-FB
fast Fourier transform
auto-regressive coefficients
LPTS
transformat Fouriera
współczynnik regresji
Opis:
An innovative Frictional Sound Automatic Measuring System (FSAMS) was designed to collect and enable analysis of the frictional sound spectra of four natural fibre woven fabrics which included cotton, linen, silk, and wool. The Fast Fourier Transform (FFT) method was used to convert time-domain signals into frequency-domain signals to enable the maximum sound amplitude (MSA) and the level pressure of the total sound (LPTS) of the cotton, linen, silk, and wool fabrics to be calculated and analysed. Subsequently auto-regression formulae were used to calculate the fabric auto-regressive coefficients (ARC, ARF, and ARE); the correlations between fabric frictional sound in terms of LPTS and AR coefficients, and mechanical properties as measured by KES-FB were also evaluated. Stepwise regression was then used to identify the key frictional sound parameters for the four types of fabric. The results show that LPTS values for cotton, linen, silk, and wool fabrics increase with their ARC values. It was revealed that the key mechanical parameters affecting fabric frictional sound for the four natural fibre woven fabrics were not the same for each fabric type: the parameters that influenced LPTS values were the fabric weight and bending hysteresis for the cotton fabric, tensile energy for the linen, tensile resilience for the silk and shear hysteresis at a 5° shear angle for the wool fabric.
Do analizy spektrum akustycznego czterech tkanin (bawełnianej, lnianej, jedwabnej i wełnianej) zastosowano innowacyjny system automatycznego pomiaru dźwięku tarcia (FSAMS). Do przekształcania sygnałów w dziedzinie czasu w sygnały w dziedzinie częstotliwości wykorzystano metodę szybkiej transformaty Fouriera (FFT). Następnie obliczono współczynniki autoregresji tkanin (ARC, ARF i ARE) i oceniono właściwości mechaniczne tkanin. Wyniki pokazują, że wartości poziomu ciśnienia dźwięku totalnego (LPTS) dla tkanin bawełnianych, lnianych, jedwabnych i wełnianych wzrastają wraz z wartościami współczynnika ARC. Wykazano również, że kluczowe parametry mechaniczne wpływające na tarcie tkaniny nie były takie same dla wszystkich typów tkanin. Parametrami mechanicznymi wpływającymi na wartości LPTS tkaniny bawełnianej były: ciężar i histereza zginania tkaniny, w przypadku tkaniny lnianej największy wpływ miała siła rozciągania, a w przypadku tkaniny wełnianej sprężystość powrotna.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 4 (124); 36-44
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the Friction Sound Properties of Natural-Fiber Woven Fabrics
Badanie dźwięku ciernego tkanin z włókien naturalnych
Autorzy:
Wang, P.-N.
Ho, M.-H.
Cheng, K.-B.
Murray, R.
Lin, C.-H.
Powiązania:
https://bibliotekanauki.pl/articles/232653.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
fabric sound automatic measuring system
sound level pressure
fast Fourier transform
włókna naturalne
pomiar dźwięku ciernego
poziom hałasu
transformat Fouriera
Opis:
An innovative frictional sound automatic measuring system (FSAMS) was designed and used in this study to investigate the frictional sound generated when natural-fibre woven fabrics are rubbed together. Frictional sound measurements made using the automatic FSAMS were compared with those from a manual frictional sound measuring system (Manual FSAMS). The frictional sounds of four natural-fiber woven fabrics (i.e., cotton, linen, silk, and wool) were recorded; the Fast Fourier Transform method was used to convert time domain signals into frequency domain signals, and the maximum sound amplitude (MSA) and level pressure of the total sound (LPTS) of cotton, linen, silk, and wool were calculated. The results of a t test, analysis of variance, data reproducibility, and cluster spectrums measured from the four natural-fiber woven fabrics were compared for the two test equipment systems. The results from the t test and analysis of variance showed significant differences in the MSA and LPTS measured. Data reproducibility was superior to the automatic FSAMS compared with the manual FSAMS, and the cluster spectrums were more readily distinguishable.
W celu zbadania szumu generowanego podczas tarcia o siebie tkanin z włókien naturalnych zaprojektowano i wykorzystano innowacyjny, automatyczny system pomiaru dźwięku ciernego (FSAMS). Porównano wyniki otrzymane za pomocą FSAMS z wynikami otrzymanymi przy użyciu systemu manualnego (Manual FSAMS). Do badania użyto czterech tkanin z włókien naturalnych: bawełny, lnu, jedwabiu i wełny. Przeprowadzono analizę statystyczną otrzymanych wyników. Analiza danych wykazała, że wartości szumu zmierzone przy użyciu FSAMS były bardziej stabilne i reprezentatywne, niż te otrzymane przy użyciu Manual FSAMS, ponieważ w przypadku systemu manualnego na wyniki pomiaru ma wpływ czynnik ludzki i hałasy otoczenia, które powodują duże błędy eksperymentalne.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 2 (122); 34-42
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
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:
Construction of Generalized Rademacher Functions in Terms of Ternary Logic : Solving the Problem of Visibility of Using Galois Fields for Digital Signal Processing
Autorzy:
Vitulyova, Elizaveta S.
Matrassulova, Dinara K.
Suleimenov, Ibragim E.
Powiązania:
https://bibliotekanauki.pl/articles/2055235.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital signal processing
non-binary Galois fields
fourier transform
rademacher functions
walsh function
multivalued logic
visibility problem
algebraic extensions
ternary representation of number
Opis:
Generalized Rademacher functions, constructed as a sequence of elements of Galois fields are intended to find the spectral representation of signals with levels. These functions form a complete basis on the interval corresponding to -1 discrete time intervals and for passing into the classical Rademacher functions. The advantage of such spectra obtained using Galois Fields Fourier Transform is that the range of variation of the spectrum amplitudes remains the same as the range of variation of the original signal, which is modeled on discrete time functions taking values in the Galois field.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 2; 237--244
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Certain properties of continuous fractional wavelet transform on Hardy space and Morrey space
Autorzy:
Verma, Amit K.
Gupta, Bivek
Powiązania:
https://bibliotekanauki.pl/articles/2049016.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
fractional Fourier transform
continuous fractional wavelet transform
Hardy space
Morrey space
Opis:
In this paper we define a new class of continuous fractional wavelet transform (CFrWT) and study its properties in Hardy space and Morrey space. The theory developed generalize and complement some of already existing results.
Źródło:
Opuscula Mathematica; 2021, 41, 5; 701-723
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymmetric square root options – can we price them via the fourier transform?
Autorzy:
Ulmer, Adam
Powiązania:
https://bibliotekanauki.pl/articles/2147436.pdf
Data publikacji:
2019-06-03
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
asymmetric square root options
Fourier transform
Black-Scholes model
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2019, 20, 1; 62-71
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the computation of the GCD of 2-D polynomials
Autorzy:
Tzekis, P.
Karampetakis, N. P.
Terzidis, H. K.
Powiązania:
https://bibliotekanauki.pl/articles/929803.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
największy wspólny dzielnik
dyskretne przekształcenie Fouriera
wielomian dwuzmienny
greatest common divisor
discrete Fourier transform
two-variable polynomial
Opis:
The main contribution of this work is to provide an algorithm for the computation of the GCD of 2-D polynomials, based on DFT techniques. The whole theory is implemented via illustrative examples.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 4; 463-470
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface functionalization of poly(L-lactide-co-glycolide) membranes with amphiphilic poly(2-oxazoline) for guided tissue regeneration and treatment of bone tissue defects
Autorzy:
Tryba, A. M.
Krok-Borkowicz, M.
Paluszkiewicz, C.
Pamuła, E.
Powiązania:
https://bibliotekanauki.pl/articles/283890.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
poly (L-lactide-co-glycolide)
poly (ethylene glycol)
poly (2-oxazolines)
phase separation
Fourier transform infrared spectroscopy (FTIR)
osteoblast-like cells
guided tissue regeneration (GTR)
bone tissue engineering
Opis:
The main challenge of this research was to functionalize the surface of poly(L-lactide-co-glycolide) (PLGA) membranes with amphiphilic poly(2-oxazoline) (POx) in order to change PLGA chemical state and properties. Poly(2-oxazolines) are very powerful polymers, which thanks to active pendant groups can be easily functionalized with biologically active molecules or peptides. The membranes were prepared by dissolving PLGA, POx, and poly(ethylene glycol) (PEG, 1000 Da) in methylene chloride (DCM), followed by PEG leaching. POx molecules were preferentially adsorbed at the interface PLGA-POx-PEG thanks to affinity to both hydrophilic (PEG) and hydrophobic (PLGA) chains. The properties of the membranes were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and wettability tests. Cytocompatibility of the materials in contact with osteoblast-like MG-63 cells was studied by evaluation of cell viability (Alamar-Blue test), live/dead and phalloidin/DAPI staining. The results show that the presence of POx influenced topography of the PLGA membranes, but did not have an impact on their wettability. All membranes were fo-und cytocompatible with model osteoblasts. Presence of POx resulted in better cell adhesion as shown by microscopic studies after fluorescence staining for nuclei and cytoskeleton actin filaments. In summary, one-step phase separation process between PLGA, PEG, and POx, dissolved in DCM followed by drying and PEG leaching resulted in cytocompatible PLGA membranes with immobilised POx, which might be considered for guided tissue regeneration technique in periodontology and in bone tissue engineering.
Źródło:
Engineering of Biomaterials; 2018, 21, 147; 16-20
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Indicators Of Burnished Surface Evaluation – Reasons Of Application
Autorzy:
Toboła, D.
Rusek, P.
Czechowski, K.
Miller, T.
Duda, K.
Powiązania:
https://bibliotekanauki.pl/articles/221546.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface geometrical structure
slide diamond burnishing
correlation analysis
discrete Fourier transform
Opis:
Modern production technology requires new ways of surface examination and a special kind of surface profile parameters. Industrial quality inspection needs to be fast, reliable and inexpensive. In this paper it is shown how stochastic surface examination and its proper parameters could be a solution for many industrial problems not necessarily related with smoothing out a manufactured surface. Burnishing is a modern technology widely used in aircraft and automotive industries to the products as well as to process tools. It gives to the machined surface high smoothness, and good fatigue and wear resistance. Every burnished material behaves in a different manner. Process conditions strongly influence the final properties of any specific product. Optimum burnishing conditions should be preserved for any manufactured product. In this paper we deal with samples made of conventional tool steel – Sverker 21 (X153CrMoV12) and powder metallurgy (P/M) tool steel – Vanadis 6. Complete investigations of product properties are impossible to perform (because of constraints related to their cost, time, or lack of suitable equipment). Looking for a global, all-embracing quality indicator it was found that the correlation function and the frequency analysis of burnished surface give useful information for controlling the manufacturing process and evaluating the product quality. We propose three new indicators of burnishing surface quality. Their properties and usefulness are verified with the laboratory measurement of material samples made of the two mentioned kinds of tool steel.
Źródło:
Metrology and Measurement Systems; 2015, 22, 2; 263-274
0860-8229
Pojawia się w:
Metrology and Measurement Systems
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:
Fault Analysis of Worm Gear Box Using Symlets Wavelet
Autorzy:
Thamba, Narendiranath Babu
Thatikonda Venkata, Kiran Kamesh
Nutakki, Sathvik
Duraiswamy, Rama Prabha
Mohammed, Noor
Wahab, Razia Sultana
Mangalaraja, Ramalinga Viswanathan
Manivannan, Ajay Vannan
Powiązania:
https://bibliotekanauki.pl/articles/177633.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
worm gear box
FFT
Fast Fourier Transform
symlet wavelets
artificial neural Network
Opis:
This research highlights the vibration analysis on worm gears at various conditions of oil using the experimental set up. An experimental rig was developed to facilitate the collection of the vibration signals which consisted of a worm gear box coupled to an AC motor. The four faults were induced in the gear box and the vibration data were collected under full, half and quarter oil conditions. An accelerometer was used to collect the signals and for further analysis of the vibration signals, MATLAB software was used to process the data. Symlet wavelet transform was applied to the raw FFT to compare the features of the data. ANN was implemented to classify various faults and the accuracy is 93.3%.
Źródło:
Archives of Acoustics; 2020, 45, 3; 521-540
0137-5075
Pojawia się w:
Archives of Acoustics
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:
Design and computation of a lightning protection system in an urban 110 kV substation
Autorzy:
Taha, Mohammed Ibrahim
Li, Lin
Wang, Ping
Powiązania:
https://bibliotekanauki.pl/articles/140973.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CDEGS software
fast Fourier transform (FFT)
IEC 62305-3
lightning protection system (LPS)
NFPA 780 level 1
Opis:
A lightning protection system (LPS) of an urban 110 kV substation is designed and analysed according to NFPA 780 and IEC 62305-3 standards. The analysis of the LPS is established on the value of risk assessment. The total area of the plant is described by one soil layer with uniform resistivity. This study aims to improve the understanding of an unexpected manner of the grounding system beneath lightning currents by clarifying the basic concepts of the lightning protection level and the new design procedure in this paper was clarified according to NFPA-780 level 1 for a lightning protection system. The program is integrated with the CDEGS software, which provides effective geometrical modeling with object and result visualization. Furthermore, module and automated fast Fourier transform (FFT) is implemented in this study to simulate electromagnetic fields in the time and frequency domains. These current values are compared to the desired protection levels within the standards. The study results show that for the improved protection of the system against lightning, the total power grid must be considered as a source of improvement for studying shielding influence and the protection levels provided inside this substation.
Źródło:
Archives of Electrical Engineering; 2020, 69, 3; 723-738
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of vibration transmission in an air-operated demolition hammer
Autorzy:
Tabaszewski, M.
Wojsznis, M.
Powiązania:
https://bibliotekanauki.pl/articles/128111.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
vibrations
dynamic inputs
short-time Fourier transform
STFT
drgania
krótkoczasowa transformata Fouriera
Opis:
The paper presents an analysis of vibrations of a ram, body and handle of a heavy, air-operated demolition hammer. The research was conducted in order to determine the character of dynamic inputs and resulting vibrations at the tool handle which were necessary to build a structural model of local influences on an operator taking the hammer design into account. The experiment was carried out on a test stand without participation of an operator, which guaranteed repeatability of measurements and elimination of ontogenetic characteristics. The displacements of selected structural elements of the tool were recorded by means of a camera and the accelerations at the handle were recorded by means of a standard measuring apparatus. The recorded signals were subjected to the spectral analysis and the short-time Fourier transform (STFT) using dedicated software in MATLAB environment.
Źródło:
Vibrations in Physical Systems; 2016, 27; 385-390
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of the EEG Signal Classifiers LDA, NBC and GNBC Based on Time-Frequency Features
Porównanie klasyfikatorów LDA, NBC i GNBC sygnału EEG stosujących cechy czasowo-częstotliwościowe
Autorzy:
Szuflitowska, B.
Orłowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/275175.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
electroencephalograph classification
machine learning
short-time Fourier transform
time-frequency analysis
elektroencefalografia
klasyfikacja
uczenie maszynowe
krótkoczasowa transformata Fouriera
analiza czasowo-częstotliwościowa
Opis:
EEG signals are non-stationary and used to study the activities of the brain in pathology. Epilepsy belongs to the most common neurological diseases. In the paper, real EEG sequences described by a doctor as normal and epileptic (ictal and interictal) are used. In classification process these sequences are divided into training and testing subsets. The classification are performed using Short-Time Fourier Transform. Based on obtained spectrum four features have been extracted. The study presents experiments based on the analysis and classification of EEG signals using various methods, including Linear Discriminant Analysis, Naive Bayes Classifier and Gaussian Naive Bayes Classifier. The results indicated that used techniques a potential to be applied within an automatic neurologic diseases diagnosis system and could thus further increase the number of correct diagnoses.
Sygnały EEG są z definicji niestacjonarne i stosowane do badania aktywności mózgu w patologii. Epilepsja należy do najczęstszych chorób neurologicznych. W pracy użyto rzeczywistych sekwencji EEG określonych przez lekarza jako stan normalny oraz padaczka (stany napadowe oraz międzynapadowe). W procesie klasyfikacji sygnały zostały podzielone na dwa podzbiory – uczący oraz testujący. Klasyfikacja została przeprowadzona za pomocą krótkotrwałej transformaty Fouriera. Na podstawie otrzymanego widma dokonano ekstrakcji czterech cech. Badanie przedstawia eksperymenty oparte na analizie i klasyfikacji sygnałów EEG za pomocą różnych metod, w tym Liniowej Analizy Dyskryminacyjnej, Naiwnego Klasyfikatora Bayesa oraz Naiwnego Klasyfikatora Bayesa dla rozkładu Gaussa. Wyniki pokazują, że użyty algorytm może być potencjalnie stosowany w automatycznej diagnostyce schorzeń neurologicznych i może w przyszłości zwiększyć liczbę poprawnie stawianych diagnoz.
Źródło:
Pomiary Automatyka Robotyka; 2017, 21, 2; 39-45
1427-9126
Pojawia się w:
Pomiary Automatyka Robotyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The method of determining the main harmonic frequency component
Metoda wyznaczania głównej składowej harmonicznej
Autorzy:
Szczepański, Tomasz
Traczyk, Stanisław
Dziedziak, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2033179.pdf
Data publikacji:
2021
Wydawca:
Instytut Transportu Samochodowego
Tematy:
fundamental harmonic frequency
Fourier transform
główna składowa harmoniczna
transformata Fouriera
Opis:
Analysis of vibroacoustic signals is one of the more frequently used diagnostic methods for mechanical devices occurring, among the others, in the car diagnostics. Often, it happens that the most important element of the recorded course is the fundamental harmonic frequency of vibrations. Fundamental frequency indicates the main process related to the operation of the device and allows to follow its course. In the article the author’s method of determining the fundamental frequency in the signal, being the subject of a patent application, will be presented. Its theoretical basis and application examples were discussed comparing the accuracy of its use with the accuracy of other methods. The frequency range where the method finds application is shown. That is, where its accuracy turns out to be better than the accuracy of popular methods used to determine fundamental harmonic frequency component.
Analiza sygnałów wibroakustycznych jest jedną z częściej stosowanych metod diagnostycznych urządzeń mechanicznych, występującą między innymi w diagnostyce samochodowej. Często zdarza się, że najbardziej istotnym elementem rejestrowanego przebiegu jest główna składowa harmoniczna drgań. Dominująca częstotliwość świadczy bowiem o głównym procesie związanym z pracą urządzenia i pozwala śledzić jego przebieg. W artykule zostanie przedstawiona autorska metoda wyznaczania głównej częstotliwości występującej w sygnale, będąca przedmiotem zgłoszenia patentowego. Omówiono jej podstawy teoretyczne oraz przykłady zastosowania, porównując dokładność jej stosowania z dokładnością innych metod. Wskazano na zakres częstotliwości, gdzie metoda znajduje zastosowanie, to znaczy gdzie jej dokładność okazuje się lepsza, niż dotychczas stosowanych sposobów wyznaczania głównej składowej harmonicznej.
Źródło:
Transport Samochodowy; 2021, 1; 38-42
1731-2795
Pojawia się w:
Transport Samochodowy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Grape Variety, Yeast and Malolactic Fermentation on Volatile Compounds and Fourier Transform Infrared Spectra in Red Wines
Autorzy:
Stój, Anna
Czernecki, Tomasz
Sosnowska, Bożena
Niemczynowicz, Agnieszka
Matwijczuk, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/2019465.pdf
Data publikacji:
2022-03-01
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
fermentation
Saccharomyces cerevisiae
Saccharomyces bayanus
Oenococcus oeni
aroma compounds
Fourier transform infrared spectroscopy
Opis:
Volatile compounds are very important to the flavour and quality of the wine. The study aimed to determine the effect of grape variety (Rondo and Zweigelt), yeast, malolactic fermentation (MLF) and yeast×MLF interaction on the content of volatile compounds in red wines. The wines were produced by sequential inoculation with five commercial yeast strains and a commercial lactic acid bacteria (LAB) strain (induced malolactic fermentation) as well as by inoculation with five commercial yeast strains and without LAB inoculation (spontaneous malolactic fermentation). The volatile compounds were determined by headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME-GC/MS). Forty-six volatile compounds belonging to alcohols, esters, acids, aldehydes, ketones, furan compounds, sulfur compounds and volatile phenols were identified in the wines. The grape variety was the factor with a significant impact on the highest number of volatile compounds, 32 out of 46. Furthermore, 7 compounds were affected by yeast, 10 by MLF and only 3 by yeast×MLF interaction. Characteristic bands in Fourier transform infrared (FTIR) spectra were assigned to the vibrations of functional groups of volatile compounds. The whole FTIR spectra were analysed in detail; three characteristic spectral ranges for different classes of volatile compounds such as 3650-2700, 1750-1500, and below 1500 cm-1 were shown. The most remarkable spectral changes were observed for the last two areas.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2022, 72, 1; 39-55
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
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:
Limited contact dynamic solution tasks of horizontal vibrations of the stamp on the elastic half-space
Ogranichennoe reshenie dinamicheskojj kontaktnojj zadachi gorizontalnykh kolebanijj shtampa na uprugom poluprastranstve
Autorzy:
Starchenko, V.
Buryak, V.
Powiązania:
https://bibliotekanauki.pl/articles/793732.pdf
Data publikacji:
2013
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
elastic half-space
integral transform
horizontal vibration
dynamic contact
equation
Fourier transform
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2013, 13, 3
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two relations for generalized discrete Fourier transform coefficients
Autorzy:
Spałek, D.
Powiązania:
https://bibliotekanauki.pl/articles/201835.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
generalized discrete Fourier transform
coefficient errors
aliasing
dyskretna transformata Fouriera
Opis:
A new generalized discrete Fourier transform DFT that allows for sample shift δ 2 [0, T/N] in time-domain is defined. Two relations are proved for the sum of errors between generalized DFT coefficients and theirs theoretical values. The first is the equation for samples received for continuous and piecewise–smooth functions. The second relation is the inequality for samples generated by discontinuous functions. Moreover, the influence of samples shift on generalized DFT coefficients values, which leads to aliasing phenomenon, is presented.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 3; 275-281
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three phase active power filter with selective harmonics elimination
Autorzy:
Sozański, K.
Powiązania:
https://bibliotekanauki.pl/articles/141370.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active power filter
discrete fourier transform
harmonic distortion
power system harmonics
Opis:
This paper describes a three phase shunt active power filter with selective harmonics elimination. The control algorithm is based on a digital filter bank. The moving Discrete Fourier Transformation is used as an analysis filter bank. The correctness of the algorithm has been verified by simulation and experimental research. The paper includes exemplary results of current waveforms and their spectra from a three phase active power filter.
Źródło:
Archives of Electrical Engineering; 2016, 65, 1; 33-44
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaotic assessment of the heave and pitch dynamics motions of air cushion vehicles
Autorzy:
Sowayan, A. S.
Powiązania:
https://bibliotekanauki.pl/articles/1839831.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
transformata Fouriera
poduszka powietrzna
model pojazdu
air cushion vehicles
Poincaré map
fast Fourier transform
heave motion
pitching motion
Opis:
In this study, a three degrees of freedom nonlinear air cushion vehicle (ACV) model is introduced to examine the dynamic behavior of the heave and pitch responses in addition to the cushion pressure of the ACV in both time and frequency domains. The model is based on the compressible flow Bernoulli’s equation and the thermodynamics nonlinear isentropic relations along with the Newton second law of translation and rotation. In this study, the dynamical investigation was based on a numerical simulation using the stiff ODE solvers of the Matlab software. The chaotic investigations of the proposed model are provided using the Fast Fourier Transform (FFT), the Poincaré maps, and the regression analysis. Three control design parameters are investigated for the chaotic studies. These parameters are: ACV mass (M), the mass flow rate entering the cushion volume (in), and the ACV base radius (r). Chaos behavior was observed for heave, and pitch responses as well as the cushion pressure.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 2; 219-234
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The New Insight into the Theory of 2-D Complex and Quaternion Analytic Signals
Autorzy:
Snopek, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/226235.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
2-D Fourier transform
quaternion Fourier transforms
2-D Hilbert transforms
2-D analytic signals
Opis:
The paper presents the overview of the theory of 2-D complex and quaternion analytic signals with the 1st-quadrant spectrum support. Both signals are expressed as complex/hypercomplex sums of partial and total 2-D Hilbert transforms. Moreover, starting with the definition of 2-D complex and quaternion Fourier transforms, the 2-D Hilbert transforms are derived in the form of sums of parts of different parity with respect to signal-domain variables. Some new relations for Hilbert quaternion spectra have been derived. The paper is illustrated with the example of the 2-D separable Cauchy signal.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 3; 285-291
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
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:
On configuration of residue scaling process in pipelined radix-4 MQRNS FFT processor
Autorzy:
Smyk, R.
Czyżak, M.
Powiązania:
https://bibliotekanauki.pl/articles/377692.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
fast Fourier transform
residue number system
modified quadratic residue number system
FFT pipelined processor
Opis:
Residue scaling is needed in pipelined FFT radix-4 processors based on the Modified Quadratic Residue Number System (MQRNS) at the output of each butterfly. Such processor uses serial connection of radix-4 butterflies. Each butterfly comprises n subunits, one for each modulus of the RNS base and generates four complex residue numbers. In order to prevent the arithmetic overflow in the succesive stage, every number has to be scaled, i.e. divided by a certain constant. The dynamic range of the processed signal increases due to the summation within the butterfly and the transformation of coefficients of the FFT algorithm to integers. The direct approach would require eight residue scalers that would be highly ineffective regarding that such a set of scalers had to be placed after each butterfly. We show and analyze a structure which uses parallel-to-serial transformation of groups of numbers so that only two scalers are needed.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2014, 80; 145-150
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On simplification of residue scaling process in pipelined Radix-4 MQRNS FFT processor
Autorzy:
Smyk, R.
Czyżak, M.
Powiązania:
https://bibliotekanauki.pl/articles/97551.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
fast Fourier transform
residue number system
modified quadratic residue number system
pipelined FFT processor
Opis:
Residue scaling is needed in pipelined FFT radix-4 processors based on the Modified Quadratic Residue Number System (MQRNS) at the output of each butterfly. Such processor uses serial connection of radix-4 butterflies. Each butterfly comprises n subunits, one for each modulus of the RNS base and generates four complex residue numbers. In order to prevent arithmetic overflow intermediate results after each butterfly have to be scaled, i.e. divided by a certain constant. The number range of the processed signal increases due to transformation of coefficients of the FFT algorithm to integers and summation and multiplication within the butterfly. The direct approach would require eight residue scalers that would be highly ineffective regarding that such a set of scalers had to be placed after each butterfly. We show and analyze a structure which uses parallel-to-serial transformation of groups of numbers so that only two residue scalers are needed.
Źródło:
Computer Applications in Electrical Engineering; 2014, 12; 588-596
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The vertebrate skeletal muscle thick filaments are not three-stranded. Reinterpretation of some experimental data*
Autorzy:
Skubiszak, Ludmila
Kowalczyk, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/1043687.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
thick filament symmetry
mass distribution
Fourier transform
myosin molecule packing
cross-bridge movement
Opis:
Computer simulation of mass distribution within the model and Fourier transforms of images depicting mass distribution are explored for verification of two alternative modes of the myosin molecule arrangement within the vertebrate skeletal muscle thick filaments. The model well depicting the complete bipolar structure of the thick filament and revealing a true threefold-rotational symmetry is a tube covered by two helices with a pitch of 2 × 43 nm due to arrangement of the myosin tails along a helical path and grouping of all myosin heads in the crowns rotated by 240° and each containing three cross-bridges separated by 0°, 120°, and 180°. The cross-bridge crown parameters are verified by EM images as well as by optical and low-angle X-ray diffraction patterns found in the literature. The myosin tail arrangement, at which the C-terminus of about 43-nm length is near-parallel to the filament axis and the rest of the tail is quite strongly twisted around, is verified by the high-angle X-ray diffraction patterns. A consequence of the new packing is a new way of movement of the myosin cross-bridges, namely, not by bending in the hinge domains, but by unwrapping from the thick filament surface towards the thin filaments along a helical path.
Źródło:
Acta Biochimica Polonica; 2002, 49, 4; 841-853
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response due to concentrated force in micropolar elastic solid with voids
Autorzy:
Singh, R.
Singh, K.
Powiązania:
https://bibliotekanauki.pl/articles/955252.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
prawo Laplace'a
metoda Fouriera
porowatość
eigenvalue
voids
Laplace and Fourier transform
concentrated force
Romberg's integration
Opis:
The eigen value approach, following Laplace and Fourier transforms has been employed to find the general solution of the field equation in a micropolar elastic solid with voids for the plane strain problem. An application of an infinite space with impulsive force has been taken to illustrate the utility of the approach. The integral transformations have been inverted by using a numerical inversion technique to get result in physical domain. The result in the form of normal displacement, volume fraction, normal force stress, tangential force stress and tangential couple stress components has been obtained numerically and illustrated graphically to depict the effect of micropolarity and voids.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 4; 755-769
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image cipher applications using the elliptical curve and chaos
Autorzy:
Silva-García, Víctor Manuel
Flores-Carapia, Rolando
Rentería-Márquez, Carlos
Luna-Benoso, Bejamín
Chimal-Eguía, Juan Carlos
Powiązania:
https://bibliotekanauki.pl/articles/329867.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
elliptic curve
chaos
discrete Fourier transform
image ciphering
krzywa eliptyczna
dyskretna transformata Fouriera
Opis:
A novel symmetric cryptosystem of the substitution permutation network type is presented for image encryption in 14 rounds. An algorithm is developed to generate 15 keys to encrypt images where each key is the image size. These keys are calculated using an elliptic curve with a constant zero value. The proposed curve is non-singular, non-supersingular, nor trace one. Chaos is employed to find a generating element in a cyclic subgroup and it is produced using the logistic map equation. In addition, a 16 × 16 substitution box is constructed using both chaos and an algorithm that defines a bijective function. The following tools are used in order to measure the degree of randomness of the encrypted figures: entropy, correlation, the discrete Fourier transform and a goodness-of-fit test with the chi-square distribution. Furthermore, an image size variable permutation is applied in the first round, and its inverse in the fourteenth.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2020, 30, 2; 377-391
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of solutions of the 1D fractional Cattaneo heat transfer equation
Autorzy:
Siedlecka, Urszula
Ciesielski, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/2175501.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
heat transfer
Cattaneo equation
fractional Caputo derivative
Laplace transform
Fourier transform
wymiana ciepła
równanie Cattaneo
pochodna ułamkowa Caputo
transformata Laplace'a
transformata Fouriera
Opis:
In this paper, a solution of the single-phase lag heat conduction problem is presented. The research concerns the generalized 1D Cattaneo equation in a whole-space domain, where a second order time derivative is replaced by the fractional Caputo derivative. The Fourier-Laplace transform technique is used to determine a solution of the considered problem. The numerical inversion of the Laplace transforms is applied. The effect of the order of the fractional derivative on the temperature distribution is investigated.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 4; 87--98
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete trigonometric transform and its usage in digital image processing
Autorzy:
Shumeiko, A.
Smorodskyi, V.
Powiązania:
https://bibliotekanauki.pl/articles/411271.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
discrete cosine transform
discrete Fourier transform
discrete trigonometric transform
signal
filter
Opis:
The achieved discrete trigonometric transform allows building of adaptive filters to suit their area of application. By varying the phase shift can be achieved improved quality of source data recovery in case the frequency coefficients undergo distortion. This transformation is well manifested itself in the problem of image compression, showing better results than the discrete cosine transform.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2017, 6, 4; 21-26
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Correlation Using Four Wave Mixing in a Highly Nonlinear Fibre for Real-Time Serialized Ultrafast Systems
Autorzy:
Shalihah, F.
Mitchell, A.
Bui, L.
Powiązania:
https://bibliotekanauki.pl/articles/226196.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
broadband
Dispersive Fourier Transform
four wave mixing
nonlinearity
optical correlation
Optical Signal Processing
Real-Time Ultrafast Systems
Opis:
A method of all-optical correlation is proposed using the nonlinear phenomena Four Wave Mixing (FWM) of two different signals. The method shows a serial solution where correlation of an ultrafast real-time serialized broadband source is demonstrated using a Highly Non-Linear Fibre (HNLF) with correlation rate reaching 200MHz.
Źródło:
International Journal of Electronics and Telecommunications; 2013, 59, 3; 207-212
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemical footprint of the solvent soluble extraterrestrial organic matter occluded in Sołtmany ordinary chondrite
Autorzy:
Schmitt-Kopplin, P.
Harir, M.
Kanawati, B.
Tziozis, D.
Hertkorn, N.
Gabelica, Z.
Powiązania:
https://bibliotekanauki.pl/articles/411511.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Meteorytowe
Tematy:
ordinary chondrite
extraterrestrial organic matter
carbon
nitrogen
sulphur
meteorite
Sołtmany
nuclear magnetic
resonance spectroscopy (NMR)
Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS)
Opis:
By characterizing organic molecules of extra-terrestrial origin included in the Sołtmany meteorite, we also present the first results of the non-targeted chemical analysis of the methanol soluble organic matter present in an L6 ordinary chondrite. The structural characterization by means of ultrahigh resolution Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS) with electrospray ionization (ESI) in negative and positive modes demonstrated an unexpected and astonishing chemical diversity with several thousand mass peaks that could be converted into C, H, N, O, S, and P elemental compositions. Molecular signatures were typically those of considerably oxygenated CHO and CHOS molecular series of primarily aliphatic character. 1H nuclear magnetic resonance (NMR) spectroscopy confirmed the prevalent existence of pure and functionalized aliphatic spin systems of intermediate chain length (C3-4 units), oxygenated aliphatics and a considerable diversity of oxygenated aromatics in the proton-based abundance ratio near 24 : 2 : 1. Although only residual organic matter allegedly survives in highly thermally altered L6 chondrites, the physical protection of organic matter in microcavities and traps between mineral surfaces might have supported and governed the chemistry with an apparent recalcitrance of extraterrestrial organic matter (EOM). Future studies of the organic matter in ordinary chondrites and its composition and structure in various regimes of (e.g.) temperature, radiation, pressure, and water content could shed light on these meteorites’ formation and evolution.
Źródło:
Meteorites; 2012, 2, No. 1-2; 79-92
2299-0313
2299-1220
Pojawia się w:
Meteorites
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pre-treatment effect on the structure of bacterial cellulose from Nata de Coco (Acetobacter xylinum)
Wpływ wstępnej obróbki na strukturę celulozy bakteryjnej z Nata de Coco (Acetobacter xylinum)
Autorzy:
Rusdi, Rusaini Athirah Ahmad
Halim, Norhana Abdul
Nurazzi, Mohd Norizan
Abidin, Zul Hazrin Zainal
Abdullah, Norli
Che Ros, Fadhlina
Ahmad, Nurazlin
Azmi, Ahmad Farid Mohd
Powiązania:
https://bibliotekanauki.pl/articles/2088276.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
bacterial cellulose
structure
X-ray diffraction
Fourier transform infrared spectroscopy
field emission scanning electron microscopy
celuloza bakteryjna
struktura
dyfrakcja rentgenowska
spektroskopia w podczerwieni z transformacją Fouriera
skaningowa mikroskopia elektronowa z emisją polową
Opis:
This paper presents a structural analysis of various methods to produce bacterial cellulose (BC) from Nata de Coco (Acetobacter xylinum). BC sheet, BC chem and BC mech powders were successfully prepared using oven drying, chemical and mechanical treatment. The X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FESEM) were used to analyze the structure of prepared BC. The structure of bacterial cellulose was compared with the structure of commercial microcrystalline cellulose (MCC) and cotton fabric. The XRD results showed that the BC sheet sample had the highest degree of crystallinity (81.76%) compared to cotton cellulose (75.73%). The crystallite size of cotton was larger than the BC sheet, with the value of 6.83 ηm and 4.55 ηm, respectively. The peaks in the FTIR spectra of all BC were comparable to the commercial MCC and cotton fabrics. FESEM images showed that the prepared BC sheet, BC mech, and BC chem had an almost similar structure like commercial MCC and cotton fabric. It was concluded that simple preparation of BC could be implemented and used for further BC preparation as reinforcement in polymer composites, especially in food packaging.
Niniejszy artykuł zawiera analizę struktury celulozy bakteryjnej (BC) wytworzonej z Nata de Coco (Acetobacter xylinum) różnymi metodami. Folia BC i proszki BC chem oraz BC mech zo -stały wytworzone poprzez suszenie w piecu, obróbkę chemiczną i mechaniczną. Do oceny struktury celulozy bakteryjnej stosowano dyfrakcję rentgenowską (XRD), spektroskopię Fouriera w podczerwieni (FTIR) i skaningową mikroskopię elektronową z emisją polową (FESEM). Strukturę celulozy bakteryjnej porównano ze strukturą handlowej celulozy mikrokrystalicznej (MCC) i tkaniny bawełnianej. Wyniki XRD wykazały, że najwyższy stopień krystaliczności miała próbka arkusza BC (81,76%) w porównaniu z celulozą bawełnianą (75,73%). Wielkość krystalitów bawełny była większa niż folii BC i wynosiła, odpowiednio, 6,83 ηm oraz 4,55 ηm. Piki widm FTIR wszystkich otrzymanych form celulozy bakteryjnej były porównywalne z komercyjnymi tkaninami bawełnianymi i z celulozy mikrokrystalicznej. Zdjęcia FESEM folii BC oraz proszków BC mech i BC chem również były podobne do komercyjnej MCC i tkaniny bawełnianej. Stwierdzono, że z wykorzystaniem prostych technik można otrzymać BC, która może być stosowana jako wzmocnienie w kompozytach polimerowych, w szczególności w opakowaniach do żywności.
Źródło:
Polimery; 2022, 67, 3; 110--118
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic processor of the MCM sonar
Procesor akustyczny sonaru MCM
Autorzy:
Rudnicki, M.
Schmidt, J.
Schmidt, A.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/282134.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
MCM sonar
second order sampling
digital phase beamformer
Fourier transform
spatial frequency
VME bus
sonar MCM
próbkowanie drugiego rządu
cyfrowy beamformer fazowy
przekształcenie Fouriera
częstotliwość przestrzenna
VMEBus
Opis:
This paper presents the concept of an acoustic processor of the mine countermeasure sonar. Developed at the Department of Marine Electronics Systems, Gdańsk University of Technology, the acoustic processor is an element of the MG-89, a modernised underwater acoustic station. The focus of the article is on the modules of the processor. They are responsible for sampling analogue signals and implementing the algorithms controlling the measurement cycle and digital signal processing. As it performs the above funetions, the device should be highly reliable and resistant to mechanical and weather conditions and ensure a user friendly operation. The functions of the processor software should help with object detection and classification. In addition to these properties, the acoustic processor should operate in real time. The results of measurements should be displayed with the shortest possible delay in relation to sounding signals to allow the operator to take decisions ąuickly and establish if the object poses a risk.
W artykule przedstawiono koncepcję procesora akustycznego sonaru MCM (ang. Mine Countermeasure Sonar), opracowaną i zrealizowaną w Katedrze Systemów Elektroniki Morskiej Politechniki Gdańskiej. Opisany procesor akustyczny jest elementem zmodernizowanej stacji hydrolokacyjnej MG-89. Zwrócono szczególną uwagę na moduły procesora, które odpowiadają za proces próbkowania sygnałów analogowych oraz realizują algorytmy sterowania cyklem pomiarowym i cyfrowego przetwarzania sygnałów. Urządzenie to przy wykonywaniu wyżej wymienionych funkcji powinno cechować się dużą niezawodnością oraz odpornością na narażenia mechaniczne i klimatyczne, a z punktu widzenia operatora - łatwością obsługi. Oprogramowanie procesora powinno zawierać funkcje ułatwiające detekcję i klasyfikację wykrytych obiektów. Poza wymienionymi właściwościami procesor akustyczny powinien również być systemem czasu rzeczywistego. Wyniki pomiarów powinny pojawiać się na zobrazowaniu z możliwie najmniejszym opóźnieniem, w stosunku do sygnałów sondujących, tak aby operator systemu mógł, w jak najkrótszym czasie, podjąć decyzję, czy wykryty obiekt jest niebezpieczny.
Źródło:
Automatyka / Automatics; 2013, 17, 1; 73-82
1429-3447
2353-0952
Pojawia się w:
Automatyka / Automatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The heat transfer and flow structure analyses of low concentration copper nanofluids in a strong magnetic field
Autorzy:
Roszko, A.
Fornalik-Wajs, E.
Powiązania:
https://bibliotekanauki.pl/articles/175547.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanofluids
heat transfer
flow structure
fast Fourier transform
Nusselt number ratio
thermomagnetic Rayleigh number
Opis:
Main aim of this paper was to analyze the influence of strong magnetic field on the enhancement or suppression of nanofluids transport processes. The second objective was to determine how the flow structure changed under the influence of a magnetic field. Analyzed diamagnetic nanofluids composed of distilled water and the copper nanoparticles of 40–60 nm size in three different concentrations (50, 500, and 1000 ppm). The experimental enclosure position in the magnet test section caused the most intricate interaction of the acting forces: the gravitational and magnetic buoyancy ones, and made the interpretation of results very difficult. The Nusselt number ratio and the thermomagnetic Rayleigh number were determined for heat transfer analysis, while the fast Fourier transform was performed for the nanofluid flow structure analysis. Spectral analysis for all examined nanofluids was presented. Influence of nanoparticles concentration was clearly visible, while the direct impact of magnetic field on the heat transfer and flow structure should be still investigated.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 29-42
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anti – plane crack emanating from the interface in a bounded smart PEMO- elastic structure
Autorzy:
Rogowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/955285.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
interfejs
natężenie pola
transformacja Fouriera
równanie Cauchy'ego
interface
anti-plane shear crack
singularity of power law
field intensity factors
magnetoelectroelastic behaviour
Fourier transform
Cauchy singular integral equation
exact solution
Opis:
The magnetoelectroelastic analysis of two bonded dissimilar piezo-electro-magneto-elastic ceramics with a crack perpendicular to and terminating at the interface is made. By using the Fourier integral transform (in perpendicular directions in each materials), the mixed boundary conditions and continuity conditions are transformed to a singular integral equation with generalized Cauchy kernel, the solution of which has been well studied, and classical methods are directly applicable here to obtain the closed form solution. The results are presented for a permeable crack under anti-plane shear loading and in-plane electric and magnetic loadings, as prescribed electric displacement and magnetic inductions or electric and magnetic fields. The results indicate that the magnetoelectroelastic field near the crack tip in the homogeneous PEMO- elastic ceramic is dominated by a traditional inverse square-root singularity, while the coupled field near the crack tip at the interface exhibits the singularity of the power law r--α , r being the distance from the interface crack tip and α depending on the material constants of a bimaterial. In particular, electric and magnetic fields have no singularity at the crack tip in a homogeneous solid, whereas they are singular around the interface crack tip. Numerical results are given graphically to show the effects of the material properties on the singularity order, field intensity factors and energy release rates. The results presented in this paper should have potential applications to the design of multilayered magnetoelectroelastic structures.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 4; 1165-1199
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
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

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