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Tytuł:
3D Synthetic Aperture Imaging Method in Spectrum Domain for Low-Cost Portable Ultrasound Systems
Autorzy:
Tasinkiewicz, Jurij
Powiązania:
https://bibliotekanauki.pl/articles/31339771.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ultrasound imaging
matrix transducer
delay-and-sum
Fourier transform
synthetic aperture
Opis:
Portable, hand-held ultrasound devices capable of 3D imaging in real time are the next generation of the medical imaging apparatus adapted not only for professional medical stuff but for a wide group of less advanced users. Limited power supply capacity and the relatively small number of channels used for the ultrasound data acquisition are the most important limitations that should be taken into account when designing such devices and when developing the corresponding image reconstruction algorithms. The aim of this study was to develop a new 3D ultrasound imaging method which would take into account the above-mentioned features of the new generation of ultrasonic devices – low-cost portable general access scanners. It was based on the synthetic transmit aperture (STA) method combined with the Fourier spectrum domain (SD) acoustic data processing. The STA using a limited number of elements in transmit and receive modes for ultrasound data acquisition allowed both aforementioned constraints to be obeyed simultaneously. Moreover, the computational speed of the fast Fourier transform (FFT) algorithm utilized for the ultrasound image synthesis in the spectrum domain makes the proposed method to be more competitive compared to the conventional time domain (TD) STA method based on the delay-and-sum (DAS) technique, especially in the case of 3D imaging in real time mode. Performance of the proposed method was verified using numerical 3D acoustic data simulated in the Field II program for MATLAB and using experimental data from the custom design 3D scattering phantom collected by means of the Verasonics Vantage 256™ research ultrasound system equipped with the dedicated 1024-element 2D matrix transducer. The method proposed in this paper was about 80 times faster than its counterpart based on the time domain synthetic transmit aperture (TD-STA) approach in the numerical example of a single 3D ultrasound image synthesized from 4 partial images each containing 64 × 64 × 512 pixels. It was also shown that the acceleration of the image reconstruction was achieved at the cost of a slight deterioration in the image quality assessed by the contrast and contrast-to-noise ratio (CNR).
Źródło:
Archives of Acoustics; 2023, 48, 4; 559-572
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnosis of ITSC fault in the electrical vehicle powertrain system through signal processing analysis
Autorzy:
Ouamara, Dehbia
Boukhnifer, Moussa
Chaibet, Ahmed
Maidi, Ahmed
Powiązania:
https://bibliotekanauki.pl/articles/2174472.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
induction motor
electrical vehicle
fault diagnosis
inter-turn short circuit
extended Kalman filter
spectral analysis
fast Fourier transform
short-time Fourier transform
silnik indukcyjny
pojazd elektryczny
diagnostyka uszkodzeń
zwarcie międzyzwojowe
rozszerzony filtr Kalmana
analiza spektralna
szybka transformata Fouriera
krótkoczasowa transformata Fouriera
Opis:
The three-phase induction motor is well suited for a wide range of mobile drives, specifically for electric vehicle powertrain. During the entire life cycle of the electric motor, some types of failures can occur, with stator winding failure being the most common. The impact of this failure must be considered from the incipient as it can affect the performance of the motor, especially for electrically powered vehicle application. In this paper, the intern turn short circuit of the stator winding was studied using Fast Fourier transform (FFT) and Shor-Time Fourier transform (STFT) approaches. The residuals current between the estimated currents provided by the extended Kalman filter (EKF) and the actual ones are used for fault diagnosis and identification. Through FFT, the residual spectrum is sensitive to faults and gives the extraction of inter-turn short circuit (ITSC) related frequencies in the phase winding. In addition, the FFT is used to obtain information about when and where the ITSC appears in the phase winding. Indeed, the results allow to know the faulty phase, to estimate the fault rate and the fault occurrence frequency as well as their appearance time.
Źródło:
Diagnostyka; 2023, 24, 1; art. no. 2023113
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of sway and roll excitations on sloshing loads in a KC-1 membrane LNG tank
Autorzy:
An, Se-yeol
Jeong, Hyeon-won
Kim, Ohyoung
Shim, W. Jaewoo
Powiązania:
https://bibliotekanauki.pl/articles/34600997.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
KC-1 membrane LNG tank
sloshing
sway
roll
coupled sway-roll
Fast Fourier transform (FFT)
Opis:
This study investigates the effects of sway and roll excitations on sloshing liquid loads in a tank, using Ansys Fluent software. The model considered in the study is a 1:50 scaled membrane-type tank, based on a KC-1 membrane LNG tank designed by Korea Gas Corporation (KOGAS). The volume of fluid (VOF) method is used to track the free surface inside the tank, and the standard k-ε model is applied to express the turbulent flow of the liquid. To explore the motion of the tank under excitation, a user-defined function (UDF) and a dynamic mesh technique are employed to control the external forces exerted on the tank through its motion. The results, in the form of time series data on the sloshing pressures in the tank under pure sway, roll, and coupled sway-roll, are analysed, with specific ranges for the excitation amplitudes and frequencies. We show that variations in excitation frequency and amplitude significantly influence the sloshing loads. Sloshing loads are found to intensify when the excitation frequency matches the tank’s primary natural frequency, 1.0 ω'1. Furthermore, with coupled sway-roll excitations, the sloshing loads are weakened when the sway and roll are in-phase and are intensified when these are out-of-phase. Fast Fourier transform analysis provides insights into the frequency domain, showing that the dominant frequency is 0.88 Hz and it is approximately equal to the tank’s primary natural frequency, 1.0 ω'1.
Źródło:
Polish Maritime Research; 2023, 4; 43-53
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-security image encryption by multiplexing phase encoding in domains of dual optical transforms
Autorzy:
Li, Zhihui
Gao, Bin
Pan, Xiaoou
Li, Linlin
Wang, Chenxuan
Zuo, Weizhuo
Ji, Yu
Liu, Shutian
Liu, Zhengjun
Powiązania:
https://bibliotekanauki.pl/articles/27310099.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
extended fractional Fourier transform
geometric operations
random phase encoding
Opis:
A novel optical image encryption is proposed based on multiplexing of the random phase encoding with shift and rotation operations in domains of two transforms, extended fractional Fourier transform (eFrFT) and Fresnel transform. The original image is subjected to eFrFT with the action of the random phase mask. The mask is shifted and rotated to enhance the security of this encryption method. The image obtained from eFrFT is entered into Fresnel diffraction by the use of the phase mask to obtain the final encrypted image. We plan for the phase keys to be multiplexed in order to decrease the amount of keys that need to be stored in an application. Here, the displacement, rotation angle, and wavelength in this system can be used as additional keys to improve the security and reliability of the encryption system. Numerical experiments are conducted to verify the effectiveness and security of the method. The findings demonstrate that the keys are sufficiently sensitive for high security.
Źródło:
Optica Applicata; 2023, 53, 3; 447--466
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrasound Signal Classification Based on ICA and SVM
Autorzy:
Lu, Quanbo
Wang, Meng
Li, Mei
Powiązania:
https://bibliotekanauki.pl/articles/31339863.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
independent component analysis
fast Fourier transform
support vector machine
infrasound signal
Opis:
A diagnostic technique based on independent component analysis (ICA), fast Fourier transform (FFT), and support vector machine (SVM) is suggested for effectively extracting signal features in infrasound signal monitoring. Firstly, ICA is proposed to separate the source signals of mixed infrasound sources. Secondly, FFT is used to obtain the feature vectors of infrasound signals. Finally, SVM is used to classify the extracted feature vectors. The approach integrates the advantages of ICA in signal separation and FFT to extract the feature vectors. An experiment is conducted to verify the benefits of the proposed approach. The experiment results demonstrate that the classification accuracy is above 98.52% and the run time is only 2.1 seconds. Therefore, the proposed strategy is beneficial in enhancing geophysical monitoring performance.
Źródło:
Archives of Acoustics; 2023, 48, 3; 191-199
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mycoremediation of Heavy Metals Contaminated Soil by Using Indigenous Metallotolerant Fungi
Autorzy:
Akram, Muhammad Bilal
Khan, Ibrar
Ur Rehman, Mujaddad
Sarwar, Abid
Ullah, Najeeb
ur Rahman, Shafiq
Aziz, Tariq
Alharbi, Metab
Alshammari, Abdulrahman
Alasmari, Abdullah F.
Powiązania:
https://bibliotekanauki.pl/articles/27315654.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Mycoremediation
Heavy Metals Contaminated Soil
Korangi Industrial Estate
FTIR
Fourier Transform Infrared Spectroscopy
SEM
Scanning Electron Microscope
Opis:
The present study was aimed to identify the indigenous fungal strains which could possibly be applied to the bioremediation of heavy metal-contaminated soil. The contaminated soil samples of Korangi Industrial Estate Karachi were found to have total concentration of Cu 1.044 mgL1 , and Pb 0.631 mgL–1. A total of eight indigenous strains of the fungus were isolated and screened for bioremediation capacity from heavy metals-contaminated soil. For the bioremediation of Lead (Pb) these same indigenous eight fungal strains were used for biological remediation. All the fungal isolated with enhanced bioremediation capability were through phenotypic and genotypical characterization. The topology of the phylograms established that the fungal isolates used in this study were allocated to: K1 (Penicillium notatum), K2 (Aspergillus parasiticus), K3 (Aspergillus fumigatus), K4 (Aspergillus flavus), K5 (Aspergillus terries), K6 (Fusarium solani), K7 (Penicillium chrysogenum), K8 (Aspergillus niger), K9 (Penicillium piceum) and K10 (Penicillium restrictum). Thus, K8 fungal isolate was found to be more efficient with maximum bioremediation capacity, for copper and lead removal efficiency, and selected for FTIR and SEM to find out the uptake of Cu and Pb which of the functional groups are involved, and further to detect the effects of bioleaching of both heavy metals on to the surface of K8 fungus biomass. The current study indicates that indigenous fungal isolates could be used with high potency to remediate or clean up the heavy metals-contaminated soil either by the technique of in situ or ex-situ bioremediation.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 3; 1--13
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidative Aging Characterization of Pyro-Oil Modified Binders Using Fourier Transform Infrared Spectroscopy
Autorzy:
Bhagat, Nikita Taran
Hadole, Hemantkumar Prakash
Ranadive, Mahadeo Sambhaji
Powiązania:
https://bibliotekanauki.pl/articles/2201866.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pyro-oil
aging
asphalt binder
FTIR
Fourier Transform Infrared
carbonyls
sulfoxides
HDPE processing
plastic waste
pyrolysis of plastics
Opis:
The numerous uses for plastics in various industries have led to an increase in its manufacturing on a global scale over time. The accumulation of plastic waste is a direct result of the daily rise in plastic demand. One of the effective and trending ways of reducing the impact of plastic waste on the environment is to pyrolyze it and use the oil obtained from it as fuel for power generation, heating, extraction of chemicals, or as an asphalt binder modifier. In this study, an attempt was made for the modification of asphalt binder with the oil obtained from plastic waste pyrolysis known as pyro-oil, and to analyse aging properties of the modified binder. This paper deals with the modification of VG30 binder with pyro-oil obtained from High Density Polyethylene (HDPE) plastic waste and the analysing the effect of aging on the modified binders. Pyro-oil is yielded from the pyrolysis process of HDPE at about 750°C. The modified binders were prepared by adding 1%, 2%, and 3% pyro-oil by total weight of VG30. The effect of aging for the unmodified and modified binders was analyzed using fourier transform infrared (FTIR) spectroscopy. The binders were short term aged and the changes in their chemical functionalities before and after aging were analyzed. Results of the FTIR test were used to calculate functional group indices for evaluating the aging characteristics of the modified binders. It was observed that binder chemistry is influenced by aging.
Źródło:
Advances in Science and Technology. Research Journal; 2023, 17, 1; 140--149
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The application of time-frequency methods of acoustic signal processing in the diagnostics of tram drive components
Autorzy:
Mokrzan, Daniel
Nowakowski, Tomasz
Szymański, Grzegorz M.
Powiązania:
https://bibliotekanauki.pl/articles/27322536.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
tram drive diagnostics
time-frequency methods
short-time fourier transform
continuous wavelet transform
acoustic pressure
cepstrum
diagnostyka napędu tramwajowego
napęd tramwajowy
metody czasowo-częstotliwościowe
transformacja falkowa
ciśnienie akustyczne
Opis:
The paper presents the course of investigations and the analysis of the possibility of applying selected methods of time frequency processing of non-stationary acoustic signals in the assessment of the technical condition of tram drive components, as well as a new combined method proposed by the authors. An experiment was performed in the form of a pass-by test of the acoustic pressure generated by a Solaris Tramino S105p tram. A comparative analysis has been carried out for an efficient case and a case with damage to the traction gear of the third bogie in the form of broken gear teeth. The recorded signal was analyzed using short-time Fourier transform (STFT) and continuous wavelet transform (CWT). It was found that the gear failure causes an increase in the sound level generated by a given bogie for frequencies within the range of characteristic frequencies of the tested device. Due to the limitations associated with the fixed window resolution in STFT and the inability to directly translate scales to frequencies in CWT, it was found that these methods can be helpful in determining suspected damage, but are too imprecise and prone to errors when the parameters of both transforms are poorly chosen. A new CWT-Cepstrum method was proposed as a solution, using the wavelet transform as a pre-filter before cepstrum signal processing. With a sampling rate of 8192 Hz, a db6 mother wavelet, and a scale range of 1:200, the new method was found to infer the occurrence of damage in an interpretation-free manner. The results were validated on an independent pair of trams of the same model with identical damage and as a reference on a pair of undamaged trams demonstrating that the method can be successfully replicated for different vehicles.
Źródło:
Archives of Transport; 2023, 68, 4; 55--75
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The heat equation on time scales
Autorzy:
Cuchta, Tom
Ferreira, Rui A. C.
Powiązania:
https://bibliotekanauki.pl/articles/29519378.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
heat equation
time scales
Fourier transform
Opis:
We present the use of a Fourier transform on time scales to solve a dynamic heat IVP. This is done by inverting a certain exponential function via contour integral. We include some specific examples and directions for further study.
Źródło:
Opuscula Mathematica; 2023, 43, 4; 475-491
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
VMD and CNN-Based Classification Model for Infrasound Signal
Autorzy:
Lu, Quanbo
Li, Mei
Powiązania:
https://bibliotekanauki.pl/articles/31339812.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
infrasound signal
variational mode decomposition
convolutional neural network
Fast Fourier Transform
Opis:
Infrasound signal classification is vital in geological hazard monitoring systems. The traditional classification approach extracts the features and classifies the infrasound events. However, due to the manual feature extraction, its classification performance is not satisfactory. To deal with this problem, this paper presents a classification model based on variational mode decomposition (VMD) and convolutional neural network (CNN). Firstly, the infrasound signal is processed by VMD to eliminate the noise. Then fast Fourier transform (FFT) is applied to convert the reconstructed signal into a frequency domain image. Finally, a CNN model is established to automatically extract the features and classify the infrasound signals. The experimental results show that the classification accuracy of the proposed classification model is higher than the other model by nearly 5%. Therefore, the proposed approach has excellent robustness under noisy environments and huge potential in geophysical monitoring.
Źródło:
Archives of Acoustics; 2023, 48, 3; 403-412
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza IR biogazu pochodzącego z przeróbki odpadów gorzelnianych
IR analysis of biogas from the processing of distillers waste
Autorzy:
Wieczorek, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/31348140.pdf
Data publikacji:
2022
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
spektrometria w podczerwieni z transformacją Fouriera (FT-IR)
kuweta gazowa
IR
biogaz
Fourier transform infrared spectrometry (FT-IR)
gas cell
biogas
Opis:
Technika spektrometrii w podczerwieni (IR) stosowana jest do identyfikacji substancji organicznych, polimerowych i w niektórych przypadkach materiałów nieorganicznych. Zgodnie z tezą, że era paliw kopalnych powoli zbliża się do końca, zaistniała konieczność szukania i testowania alternatywnych źródeł energii. Gaz ziemny zawierający metan stanowi źródło energii wytwarzające duże ilości gazów cieplarnianych. Magazynowanie i wytwarzanie energii z paliw takich jak biogaz stanowi jedno z wielu innowacyjnych podejść podczas produkcji w zamkniętych, neutralnych pod względem CO2 obiegach (biogazownie). Technologie służące do wytwarzania biogazu i wykorzystujące biogaz kwalifikują się do otrzymania dofinansowania wspierającego rozwój OZE. Biogaz jest uważany za odnawialne źródło energii, obieg węgla w cyklu produkcji jego surowców i zużycia jest zamknięty i nie wiąże się z emisją netto dwutlenku węgla. Spektrometry IR pracujące zarówno w zakresie średniej, jak i bliskiej podczerwieni dają możliwości analizy chemicznej i materiałowej z dużą czułością i dokładnością, przez co mogą być szeroko stosowane w monitorowaniu środowiska lub do kontrolowania prowadzonych procesów technologicznych. W artykule opisano analizę próbek biogazu za pomocą spektrometrii w podczerwieni z transformacją Fouriera z zastosowaniem kuwety gazowej o regulowanej drodze optycznej. Badane próbki pochodzą z przerobu odpadów gorzelnianych. Przedstawiono analizę próbek gazów wzorcowych będących głównymi składnikami biogazu oraz dokonano porównania otrzymanych widm IR z widmami rzeczywistych próbek biogazu. Podjęto próbę określenia możliwości użycia tej techniki do wykrywania zanieczyszczeń, takich jak obecność gazowego amoniaku. Przeprowadzone badania potwierdziły możliwości analityczne badania głównych składników biogazu. Zawartość substancji będących zanieczyszczeniami biogazu może okazać się za niska do ich oznaczenia w przypadku ich śladowych ilości, wtedy spektrometria IR może okazać się niewystarczająca m.in. do oceny skuteczności prowadzonych procesów oczyszczania biogazu, dlatego należy ją stosować w połączeniu z analizą GC.
The infrared (IR) spectrometry technique is used to identify organic substances, polymers and, in some cases, inorganic materials. In line with the thesis that the era of fossil fuels is slowly coming to an end, there has been a need to search for and test alternative energy sources. Natural gas containing methane is an energy source that produces large amounts of greenhouse gases. Storing and producing energy from fuels such as biogas is one of the many innovative production approaches in closed, CO2-neutral circuits (biogas plants). Technologies for the production and use of biogas are eligible for funding supporting the development of renewable energy sources. Biogas is considered to be a renewable energy source, the carbon cycle in its raw material production and consumption is closed, with zero net carbon emissions. IR spectrometers operating both in the mid-infrared and near-infrared range provide the possibility of chemical and material analysis with high sensitivity and accuracy, therefore they can be widely used in environmental monitoring or to control technological processes. The article describes the analysis of biogas samples by Fourier transform infrared spectrometry with the use of a gas cuvette with adjustable optical path. The tested samples come from the processing of distiller's waste. The paper presents the analysis of standard gas samples, which are the main components of biogas, and compares the obtained IR spectra with the spectra for real biogas samples. An attempt was made to determine the applicability of this technique for the detection of contaminants such as the presence of ammonia gas. The conducted research confirmed the analytical possibilities of examining the main components of biogas. The content of biogas pollutants may turn out to be too low for their determination in the case of trace amounts, and in such a case the IR spectrometry may turn out to be insufficient, e.g. to assess the effectiveness of biogas purification processes, therefore it should be used in conjunction with the GC analysis.
Źródło:
Nafta-Gaz; 2022, 78, 8; 630-636
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the backlash in the single stage cycloidal gearbox
Autorzy:
Król, Roman
Powiązania:
https://bibliotekanauki.pl/articles/27309870.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
cycloidal gearbox
backlash
dynamics
multibody dynamics
multibody simulation
discrete Fourier transform
spectral analysis
FFT
przekładnia cykloidalna
reakcja
dynamika
dynamika wieloczłonowa
symulacja wieloobiektowa
dyskretna transformata Fouriera
analiza spektralna
Opis:
In this paper the analysis of backlash influence on the spectrum of torque at the output shaft of a cycloidal gearbox has been performed. The model of the single stage cycloidal gearbox was designed in the MSC Adams. The analysis for the excitation with the torque and the analysis with constant angular velocity of the input shaft were performed. For these analyses, the amplitude spectrums of the output torque for different backlashes was solved using FFT algorithm. The amplitude spectrums of the combined sine functions composed of the impact to impact times between the cycloidal wheel and the external sleeves were computed for verification. The performed studies show, that the backlash has significant influence on the output torque amplitude spectrum. Unfortunately the dependencies between the components of the spectrum and the backlash could not be expressed by linear equations, when vibrations of the output torque in the range of (350 Hz – 600 Hz) are considered. The gradual dependence can be found in the spectrum determined for the combined sine functions with half-periods equal impact-to-impact times. The spectrum is narrower for high values of backlash.
Źródło:
Archive of Mechanical Engineering; 2022, LXIX, 4; 693--711
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
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:
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:
Design of a tribotechnical diagnostics model for determining the technical condition of an internal combustion engine during its life cycle
Autorzy:
Furch, Jan
Jelínek, Josef
Powiązania:
https://bibliotekanauki.pl/articles/2172026.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
tribotechnical diagnostic
Fourier transform-infrared spectrometry
kinematic viscosity
atomic emission spectrometry
ferrography
Opis:
The paper proposes a model of tribotechnical diagnostics, which allows us to determine the technical condition of an internal combustion engine within its life cycle and then take measures, including its decommissioning due to excessive wear of major components. The paper also focuses on tribodiagnostic methods that are suitable for assessing the technical condition of internal combustion engines used in various means of transport (automobiles, railway locomotives powered by internal combustion engines, aircraft powered by reciprocating internal combustion engines, special and garden equipment). An internal combustion engine from agricultural equipment was selected for the experiment and monitored throughout its life cycle. The paper describes in detail the appropriate methods used for the proposed tribotechnical diagnostics model, including the results from the measurements by these methods. The said methods were then evaluated and mutually compared. The following advanced instrumental analytical methods were used to evaluate the collected engine oil samples: atomic emission spectrometry (AES), ferrography, automatic laser counter and LNF particle classifier, FTIR infrared spectrometry. The result of the work (paper) is the design of a tribotechnical diagnostics model for determining the technical condition of an internal combustion engine during its life cycle and the determination of limit values for assessing the technical condition of a Honda GCV 165 internal combustion engine. The results are based on individual measurements.
Źródło:
Eksploatacja i Niezawodność; 2022, 24, 3; 437--445
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact solution for heat conduction inside a sphere with heat absorption using the regularized Hilfer-Prabhakar derivative
Autorzy:
Elhadedy, Hager
Latif, Mohamed S. Abdel
Nour, Hamed M.
Kader, Abbas H. Abdel
Powiązania:
https://bibliotekanauki.pl/articles/2175524.pdf
Data publikacji:
2022
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
fractional derivatives
Laplace transform
finite sine-Fourier transform
heat transfer
pochodne ułamkowe
transformata Laplace'a
skończona transformata sinusoidalna-Fouriera
wymiana ciepła
Opis:
In this article, we utilize the finite Sine-Fourier transform and the Laplace transform for solving fractional partial differential equations with regularized Hilfer-Prabhakar derivative. These transforms are used to get analytical solutions for the time fractional heat conduction equation (TFHCE) with the regularized Hilfer-Prabhakar derivative associated with heat absorption in spherical coordinates. Two cases of Dirichlet boundary conditions are considered by obtaining an analytical solution in each case. The effect of the parameters of the regularized Hilfer-Prabhakar derivative on the heat transfer inside the sphere is discussed using some figures.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 2; 27--37
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
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:
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:
Modelling of non-ideal signal sampling via averaging operation and spectrum of sampled signal predicted by this model
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/2172501.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
modelling of non-Ideal signal sampling
non-Ideal signal
spectrum of sampled signal
A/D converters
non-Ideal signal sampling
signal sampling
discrete time fourier transform
Opis:
In this paper, a novel model of a non-ideal signal sampling via a local, periodic averaging operation is present-ed. The spectrum of a sampled signal predicted by this model is also analysed as well as compared with a one following from another model.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2022, 16, 2; 274--278
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of gear teeth in the wind turbine drive train with gear contact’s uncertainty using the reliability-based design optimization
Autorzy:
Lee, Changwoo
Park, Yonghui
Powiązania:
https://bibliotekanauki.pl/articles/27309867.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
wind turbine
drive train
gear
structural analysis
dynamics
Fourier transform
reliability based design optimization
turbina wiatrowa
układ napędowy
bieg
analiza strukturalna
dynamika
optymalizacja projektu oparta na niezawodności
Opis:
Although gear teeth give lots of advantages, there is a high possibility of failure in gear teeth in each gear stage in the drive train system. In this research, the authors developed proper gear teeth using the basic theorem of gear failure and reliability-based design optimization. A design variable characterized by a probability distribution was applied to the static stress analysis model and the dynamics analysis model to determine an objective function and constraint equations and to solve the reliability-based design optimization. For the optimization, the authors simulated the torsional drive train system which includes rotational coordinates. First, the authors established a static stress analysis model which gives information about endurance limit and bending strength. By expressing gear mesh stiffness in terms of the Fourier series, the equations of motion including the gear mesh models and kinematical relations in the drive train system were acquired in the form of the Lagrange equations and constraint equations. For the numerical analysis, the Newmark Beta method was used to get dynamic responses including gear mesh contact forces. From the results such as the gear mesh contact force, the authors calculated the probability of failure, arranged each probability and gear teeth, and proposed a reasonable and economic design of gear teeth.
Źródło:
Archive of Mechanical Engineering; 2022, LXIX, 4; 713--728
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
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:
Spectral analysis for tilted fiber Bragg gratings in the corrosion detection for concrete structure
Autorzy:
Kwong, Kok Zee
Udos, Waldo
Lim, Kok-Sing
Lee, Foo Wei
Tan, Chee Ghuan
Samion, Muhamad Zharif
Ahmad, Harith
Powiązania:
https://bibliotekanauki.pl/articles/2172827.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tilted fibre Bragg grating
optical spectral analysis
Fourier transform
corrosion
steel bar
Opis:
An effective corrosion monitoring technique is sought after by the engineers for assessing the steel bar corrosion at the early stage for the maintenance and repair works, especially in the corrosive environments, such as coastal and marine. In this work, tilted fiber Bragg grating (TFBG) with the optical sensor is employed in corrosion monitoring of a reinforced concrete structure. Taking advantage of the high sensitivity of TFBG cladding resonance wavelengths to the change in the surrounding medium, the sensor is mounted on the steel bar that is embedded in a concreted block during an accelerated corrosion process. The acquired transmission spectrum of the TFBG during the procedure is digitally processed using Fourier Transform to produce an index that is sensitive to the generated corrosion product surrounding the TFBG sensor. This eases the analysis of the sophisticated TFBG transmission spectra. The generated index can be used as an indicator (indicator J ) for the corrosion process of the embedded steel bar in the concrete structure. This indicator J can act as an indicator to describe the corrosion activity and corrosion level at a specific point of the steel bar in concrete structures.
Źródło:
Optica Applicata; 2022, 52, 3; 429--439
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stator winding fault detection of permanent magnet synchronous motors based on the bispectrum analysis
Autorzy:
Pietrzak, Przemysław
Wolkiewicz, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2173641.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault diagnosis
condition monitoring
inter-turn short circuits
permanent magnet synchronous motor
bispectrum
fast Fourier transform
błędna diagnoza
monitorowanie stanu
zwarcia międzyzwojowe
silnik synchroniczny z magnesami trwałymi
bispektrum
szybka transformata Fouriera
Opis:
The popularity of high-efficiency permanent magnet synchronous motors in drive systems has continued to grow in recent years. Therefore, also the detection of their faults is becoming a very important issue. The most common fault of this type of motor is the stator winding fault. Due to the destructive character of this failure, it is necessary to use fault diagnostic methods that facilitate damage detection in its early stages. This paper presents the effectiveness of spectral and bispectrum analysis application for the detection of stator winding faults in permanent magnet synchronous motors. The analyzed diagnostic signals are stator phase current, stator phase current envelope, and stator phase current space vector module. The proposed solution is experimentally verified during various motor operating conditions. The object of the experimental verification was a 2.5 kW permanent magnet synchronous motor, the construction of which was specially prepared to facilitate inter-turn short circuits modelling. The application of bispectrum analysis discussed so far in the literature has been limited to vibration signals and detecting mechanical damages. There are no papers in the field of motor diagnostic dealing with the bispectrum analysis for stator winding fault detection, especially based on stator phase current signal.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 2; art. no. e140556
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stator Winding Fault Detection of Permanent Magnet Synchronous Motors Based on the Short-Time Fourier Transform
Autorzy:
Pietrzak, Przemysław
Wolkiewicz, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2175935.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fault diagnosis
condition monitoring
inter-turn short circuit
permanent magnet synchronous motor
short-time Fourier transform
Opis:
In modern drive systems, the high-efficient permanent magnet synchronous motors (PMSMs) have become one of the most substantial components. Nevertheless, such machines are exposed to various types of faults. Hence, on-line condition monitoring and fault diagnosis of PMSMs have become necessary. One of the most common PMSM faults is the stator winding fault. Due to the destructive character of this failure, it is necessary to use fault diagnostic methods that allow fault detection at its early stage. The article presents the results of experimental studies obtained from fast Fourier transform (FFT) and short-time Fourier transform (STFT) analyses of the stator phase current, stator phase current envelope and stator phase current space vector module. The superiority of the proposed method over the classical approach based on the stator current analysis using FFT is highlighted. The proposed solution is experimentally verified under various motor operating conditions. The application of STFT analysis discussed so far in the literature has been limited to the fault diagnosis of induction motors and the narrow range of the analysed motor operating conditions. Moreover, there are no works in the field of motor diagnostics dealing with STFT analysis for stator windings based on the stator current envelope and the stator current space vector module.
Źródło:
Power Electronics and Drives; 2022, 7, 42; 112--133
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Template Matching Using Improved Rotations Fourier Transform Method
Autorzy:
Wijaya, Marvin Chandra
Powiązania:
https://bibliotekanauki.pl/articles/2200717.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
template matching
Fourier transform
three shear rotations
image rotation
Opis:
Template matching is a process to identify and localize a template image on an original image. Several methods are commonly used for template matching, one of which uses the Fourier transform. This study proposes a modification of the method by adding an improved rotation to the Fourier transform. Improved rotation in this study uses increment rotation and three shear methods for the template image rotation process. The three shear rotation method has the advantage of precise and noisefree rotation results, making the template matching process even more accurate. Based on the experimental results, the use of 10°angle increments has increased template matching accuracy. In addition, the use of three shear rotations can improve the accuracy of template matching by 13% without prolonging the processing time.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 4; 881--888
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Behavior of Jordanian Oil Shale during Combustion Process from the El-Lajjun Deposit
Autorzy:
Gougazeh, Mousa
Alsaqoor, Sameh
Borowski, Gabriel
Alsafasfeh, Ashraf
Hdaib, Ismail I.
Powiązania:
https://bibliotekanauki.pl/articles/2173323.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
El-Lajjun oil shale
combustion
X-ray diffraction
thermogravimetric
fourier transform infrared spectroscopy
X-ray fluorescence
Opis:
The results of X-ray diffraction, thermogravimetric and FTIR spectroscopy analyses of mineral composition indicated that the El-Lajjun oil shale is principally composed of calcite, quartz with minor amounts of kaolinite), gypsum, and apatite. The obtained oil shale ash products at 830 °C and 1030 °C are dominated by lime, quartz, anhydrite, portlandite, gehlenite, and amorphous phases. The TGA weight loss curves clearly indicate that it occurred in the temperature range from 310 to 650 °C. The decomposition of oil shale carbonates was detected above 750°C. The functional groups in the organic material of oil shale are dominated by the aliphatic hydrocarbons, the semi-ash of which had diverse structures of polycyclic aromatic hydrocarbons. The most intensive of combustion occurred in the temperature range of 400–750 °C. In this temperature range, about 75 wt.% was accounted for the total mass loss.
Źródło:
Journal of Ecological Engineering; 2022, 23, 8; 133--140
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using the MIMO method to evaluate the modal properties of the elements of a wheelset in an active experiment
Autorzy:
Milewicz, Julia
Mokrzan, Daniel
Nowakowski, Tomasz
Szymański, Grzegorz M.
Powiązania:
https://bibliotekanauki.pl/articles/24202007.pdf
Data publikacji:
2022
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
modal analysis
FRF
fast Fourier transform
light railway vehicle
wheelset
analiza modalna
szybka transformata Fouriera
lekki pojazd szynowy
zestaw kołowy
Opis:
The study of the system composed of the inner disc and wheel rim of the 105Na type railway wheel, used in Polish Konstal streetcars, was aimed at determining the dynamic parameters of the object, such as the form and frequency of natural vibrations, and at evaluating the effectiveness of the method at given analysis settings. The experiment was conducted using triaxial piezoelectric transducers and a modal hammer with an aluminum head. A multiple-input, multiple-output (MIMO) testing approach was used because of the multiple excitation points and vibration measurements. A Fast Fourier Transform (FFT) of the measurements was performed in BK Connect software and the frequency response function (FRF) value waveforms were determined. The Rational Fraction Polynomial-Z method was used to extract modes from the frequency spectrum. In addition, the Complex Mode Indicator Function method was used, which resulted in the decomposition of the principal components of the FRF value matrix, allowing the identification of individual modes. The selection of the natural frequencies was performed on the basis of the obtained FRF and CMIF characteristics of the vibroacoustic response. Visualization of the form of the natural vibration was also performed. The result of the experiment was a set of comprehensive information on the modal properties of the studied object, which allowed to confirm the effectiveness of the selected method of analysis.
Źródło:
Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022324
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
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:
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:
Anatomical and functional assessment of patency of the upper respiratory tract in selected respiratory disorders - Part 1
Autorzy:
Kukwa, Andrzej
Zając, Andrzej
Barański, Robert
Nitkiewicz, Szymon
Kukwa, Wojciech
Zomkowska, Edyta
Rybak, Adam
Powiązania:
https://bibliotekanauki.pl/articles/2052154.pdf
Data publikacji:
2021
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:
The rapidly developing measurement techniques and emerging new physical methods are frequently used in otolaryngological diagnostics. A wide range of applied diagnostic methods constituted the basis for the review study aimed at presenting selected modern diagnostic methods and achieved diagnostic results to a wider group of users. In this part, the methods based on measuring the respiratory parameters of patients were analysed. Respiration is the most important and necessary action to support life and its effective duration. It is an actual gas exchange in the respiratory system consisting of removing CO2 and supplying O2. Gas exchange occurs in the alveoli, and an efficient respiratory tract allows for effective ventilation. The disruption in the work of the respiratory system leads to measurable disturbances in blood saturation and, consequently, hypoxia. Frequent, even short-term, recurrent hypoxia in any part of the body leads to multiple complications. This process is largely related to its duration and the processes that accompany it. The causes of hypoxia resulting from impaired patency of the respiratory tract and/or the absence of neuronal respiratory drive can be divided into the following groups depending on the cause: peripheral, central and/or of mixed origin. Causes of the peripheral form of these disorders are largely due to the impaired patency of the upper and/or lower respiratory tract. Therefore, early diagnosis and location of these disorders can be considered reversible and not a cause of complications. Slow, gradually increasing obstruction of the upper respiratory tract (URT) is not noticeable and becomes a slow killer. Hypoxic individuals in a large percentage of cases have a shorter life expectancy and, above all, deal with the consequences of hypoxia much sooner.
Źródło:
Metrology and Measurement Systems; 2021, 28, 4; 813-836
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Spectral and Wavelet Analysis of Stator Current to Detect Angular Misalignment in PMSM Drive Systems
Autorzy:
Pietrzak, Przemysław
Wolkiewicz, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/1956007.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fault diagnosis
permanent magnet synchronous motor
angular misalignment
fast Fourier transform
discrete wavelet transform
Opis:
This paper deals with the selected methods of detecting angular misalignment in drive systems with a permanent magnet synchronous motor (PMSM), which are based on the analysis of the stator phase current signal, as well as their experimental verification and comparison. The proposed and compared methods are spectral analysis and wavelet analysis of the stator current, stator current envelope, stator current space vector module. Furthermore, the influence of power supply frequency and load torque on the performance of the proposed diagnostic methods is also discussed. The experimental tests were carried out for an undamaged motor and for two levels of angular misalignment. The article discusses the question of exactly what damage symptoms can be extracted from each of the methods. In the case of spectral analyses, it is demonstrated which multiplicities of the failure frequency are the most sensitive to misalignment and the least sensitive to changes in motor operating condition, which may be considered novel in the case of drive systems with permanent magnet motors. It is also proven that discrete wavelet transform (DWT) of the envelope and monitoring of the value of the relevant components allows the detection of misalignment with the availability of measuring current only in one phase in various motor operating conditions.
Źródło:
Power Electronics and Drives; 2021, 6, 41; 42-60
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
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:
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:
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:
Comparison of multiband filtering, empirical mode decomposition and short-time fourier transform used to extract physiological components from long-term heart rate variability
Autorzy:
Adamczyk, Krzysztof
Polak, Adam G.
Powiązania:
https://bibliotekanauki.pl/articles/2052173.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heart rate variability
nonstationary signal analysis
multiband filtering
empirical mode decomposition
short-time Fourier transform
Hilbert transform
Opis:
Heart rate is constantly changing under the influence of many control signals, as manifested by heart rate variability (HRV). HRV is a nonstationary, irregularly sampled signal, the spectrum of which reveals distinct bands of high, low, very low and ultra-low frequencies (HF, LF, VLF, ULF). VLF and ULF components are the least understood, and their analysis requires HRV records lasting many hours. Moreover, there are still no well-established methods for the reliable extraction of these components. The aim of this work was to select, implement and compare methods which can solve this problem. The performance of multiband filtering (MBF), empirical mode decomposition and the short-time Fourier transform was tested, using synthetic HRV as the ground truth for methods evaluation as well as real data of three patients selected from 25 polysomnographic records with a clear HF component in their spectrograms. The study provided new insights into the components of long-term HRV, including the character of its amplitude and frequency modulation obtained with the Hilbert transform. In addition, the reliability of the extracted HF, LF, VLF and ULF waveforms was demonstrated, and MBF turned out to be the most accurate method, though the signal is strongly nonstationary. The possibility of isolating such waveforms is of great importance both in physiology and pathophysiology, as well as in the automation of medical diagnostics based on HRV.
Źródło:
Metrology and Measurement Systems; 2021, 28, 4; 643-660
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ellipsometry based spectroscopic complex for rapid assessment of the Bi2Te3-xSexthin films composition
Elipsometryczny system spektroskopowy do szybkiej oceny składu cienkich warstw Bi2Te3-xSex
Autorzy:
Kovalev, Vladimir
Uvaysov, Saygid
Bogucki, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2070267.pdf
Data publikacji:
2021
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
thin films
optical properties
spectroscopy
Fourier transform
ellipsometry and polarimetry
optics on surfaces
instrumentation
measurement and metrology
cienka warstwa
właściwości optyczne
spektroskopia
transformata Fouriera
elipsometria i polarymetria
optyka cienkowarstwowa
oprzyrządowanie
pomiary i metrologia
Opis:
A comparative analysis of the current state and development of spectral ellipsometry (SE) is carried out, the main limitations typical of popular configurations of measuring devices are determined. An original technical solution is proposed that allows one to create a two-source SE that implements the ellipsometry method with switching orthogonal polarization states. The measuring setup provides high precision of measurements of ellipsometric parameters Ψand Δin the spectral range of 270–2200 nm and the speed determined by the characteristics of pulsed sources with a simple ellipsometer design.As objects for experimental researches, confirming the efficiency and high precision qualities of the fabricated SE, we used a GaAs/ZnS-quarter-wave device for a CO2laser and SiO2on Si calibration plates. The optical properties of Bi2Te3-xSexfilms were investigated in the range of 270–1000 nm using a multi-angle SE. It was shown that the optical properties of Bi2Te3-xSexfilms monotonically change depending on the ratio of selenium and tellurium.
W artykule najpierw dokonano analizy porównawczej obecnego stanu rozwoju elipsometriispektroskopowej oraz określono główne ograniczenia typowe dla popularnych konfiguracji urządzeń pomiarowych. Zaproponowano oryginalne rozwiązanie techniczne pozwalające na stworzenie dwuźródłowego elipsometu spektroskopowego z przełączaniem ortogonalnych stanów polaryzacji. Układ pomiarowy zapewnia wysoką precyzję pomiarów parametrów elipsometrycznych Ψ i Δ w zakresie spektralnym 270–2200 nm i prędkości wyznaczonej przez charakterystyki źródeł impulsowych przy prostej konstrukcji elipsometru. Jako obiekty do badań eksperymentalnych potwierdzających wydajność i wysoką precyzję proponowanego elipsometu spektroskopowego, wykorzystano ćwierćfalowy przyrząd GaAs/ZnS dla lasera CO2oraz płytki kalibracyjne SiO2na krzemie. Właściwości optyczne warstw Bi2Te3-xSexzbadano w zakresie 270–1000 nm przy użyciu wielokątowego elipsometu spektroskopowego. Wykazano, że właściwości optyczne cienkich warstw Bi2Te3-xSexzmieniają się monotonicznie w zależności od stosunku zawartości selenu i telluru.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2021, 11, 4; 67--74
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis method for an aerospace generator rotating rectifier based on dynamic FFT technology
Autorzy:
Feng, Sai
Cui, Jiang
Zhang, Zhuoran
Powiązania:
https://bibliotekanauki.pl/articles/1849142.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aerospace generator
rotating rectifier
fault diagnosis
dynamic Fast Fourier Transform
feature extraction
Opis:
A fault diagnosis method for the rotating rectifier of a brushless three-phase synchronous aerospace generator is proposed in this article. The proposed diagnostic system includes three steps: data acquisition, feature extraction and fault diagnosis. Based on a dynamic Fast Fourier Transform (FFT), this method processes the output voltages of aerospace generator continuously and monitors the continuous change trend of the main frequency in the spectrum before and after the fault. The trend can be used to perform fault diagnosis task. The fault features of the rotating rectifier proposed in this paper can quickly and effectively distinguish single and double faulty diodes. In order to verify the proposed diagnosis system, simulation and practical experiments are carried out in this paper, and good results can be achieved.
Źródło:
Metrology and Measurement Systems; 2021, 28, 2; 269-288
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fourier, Laguerre, Laplace Transforms with applications
Autorzy:
Aghili, Arman
Powiązania:
https://bibliotekanauki.pl/articles/2052384.pdf
Data publikacji:
2021
Wydawca:
Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
Tematy:
Fourier transform
Laplace transform
Laguerre transform
singular integral equation
Bessel's functions
fractional heat equation
przekształcenie Fouriera
przekształcenie Laplace'a
przekształcenie Laguerre'a
osobliwe równanie całkowe
funkcje Bessela
ułamkowe równanie ciepła
Opis:
In this article, the author considered certain time fractional equations using joint integral transforms. Transform method is a powerful tool for solving singular integral equations, integral equation with retarded argument, evaluation of certain integrals and solution of partial fractional differential equations. The obtained results reveal that the transform method is very convenient and effective. Illustrative examples are also provided.
Źródło:
Journal of Mathematics and Applications; 2021, 44; 5-17
1733-6775
2300-9926
Pojawia się w:
Journal of Mathematics and Applications
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:
In situ methanolic solvent synthesis, spectroscopic and thermogravimetric characterizations of three new transition metal complexes of trimethoprim drug
Autorzy:
Refat, Moamen S.
Al-Humaidi, Jehan Y.
El-Sayed, Mohamed Y.
Hassan, Reham F.
Powiązania:
https://bibliotekanauki.pl/articles/1849325.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
complexation
trimethoprim
transition metals
TGA
thermogravimetric analysis
FTIR
Fourier transform infrared spectroscopy
ESR
kinetic thermodynamic parameters
Opis:
Trimethoprim drug (TMP) complexes of copper (II), cobalt (II), and nickel (II) were prepared and discussed by using elemental analysis (C, H, N analysis), magnetic, molar conductance, FTIR, Raman spectroscopy, electron spin resonance (ESR) and UV-vis spectroscopy analyses. TMP drug coordinated as a tridentate ligand towards the respected three metal ions through two nitrogen atoms of amino groups and nitrogen atom of pyrimidine ring which flanked between –NH2 groups, these assignments confirmed by spectroscopic, magnetic, ESR and thermogravimetric analyses with formulas [Cu(TMP)(H2O)3]Cl2, [Co(TMP)(H2O)3]Cl2 and [Ni(TMP) (H2O)]Cl2. Copper (II) and cobalt (II) complexes have an octahedral geometrical structure included one TMP molecule, three coordinated water molecules and two uncoordinated chlorine atoms while, nickel(II)–TMP complex has a tetrahedral geometric configuration that involved one TMP molecule, one coordinated water molecule and two uncoordinated chlorine atoms. The activation energies and other kinetic thermodynamic parameters were estimated based on the employed of the Coats-Redfern and Horowitz-Metzger equations. The nano–structured form of the synthesized TMP complexes was confirmed dependent on the transmission electron microscopy (TEM).
Źródło:
Polish Journal of Chemical Technology; 2021, 23, 1; 60-67
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
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:
Mobilny system przetwarzania obrazu oparty na platformie Raspberry Pi 4
Mobile image processing system based on the Raspberry Pi 4 platform
Autorzy:
Chlastawa, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/2014237.pdf
Data publikacji:
2021
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
cyfrowe przetwarzanie obrazów
dwuwymiarowa szybka transformacja Fouriera
biblioteka OpenCV
aplikacja okienkowa
system wizyjny
digital image processing
two-dimensional fast Fourier transform
OpenCV library
window application
vision system
Opis:
W artykule zaprezentowano system przetwarzania obrazu oparty na platformie Raspberry Pi (RPi). Na początku artykułu omówiono podstawowe założenia oraz cel wykonania systemu. W dalszej części przedstawiono strukturę i sposób działania systemu. Zaprezentowano aplikację okienkową zarządzającą systemem oraz pozwalającą na wykonanie przekształceń kontekstowych oraz widmowych na obrazach, jak również pomiar parametrów, takich jak: czas przetwarzania obrazu oraz błąd średniokwadratowy (ang. Mean Square Error – MSE). Wykonywane przekształcenia oparto zarówno na gotowych formułach zawartych w bibliotece OpenCV, jak również własnych implementacjach, a wśród nich na funkcji realizującej algorytm szybkiej transformacji Fouriera FFT (ang. Fast Fourier Transform) radix-2. Zaprezentowano przykłady przekształceń wraz ze wskazaniem ich użyteczności. Na końcu przedstawiono potencjał rozwojowy utworzonego systemu oraz zaproponowano zastosowanie w konkretnych rozwiązaniach.
The article presents an image processing system based on the Raspberry Pi (RPi) platform. At the beginning of the article, the basic assumptions and purpose of the system are discussed. The following section presents the structure and operation of the system. The window application managing the system and allowing to perform contextual and spectral transformations on images as well as the measurement of parameters such as image processing time and mean square error (MSE) was discussed. The transformations performed were based both on ready formulas contained in the OpenCV library and the author’s implementations, including the function implementing the Fast Fourier Transform algorithm radix-2. Examples of transformations were presented along with their usefulness. In the end, the development potential of the created system is presented and its application in specific solutions is proposed.
Źródło:
Science, Technology and Innovation; 2021, 12, 1; 16-25
2544-9125
Pojawia się w:
Science, Technology and Innovation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis of DFT-S-OFDM waveform for Li-Fi systems
Autorzy:
Hussin, S.
Shalaby, E. Mansour
Powiązania:
https://bibliotekanauki.pl/articles/2063891.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
light-fidelity
visible light communications
orthogonal frequency division multiplexing
discrete Fourier transform spread
peak-to-average power ratio
Opis:
In this paper, the effect of an indoor visible light communication channel is studied. Moreover, the analysis of the received power distribution of the photodiode in the line of sight and the first reflection of the channel without line of sight with several parameters is simulated. Two different waveforms are explained in detail. Orthogonal frequency division multiplexing has been widely adopted in radio frequency and optical communication systems. One of the most important disadvantages of the orthogonal frequency division multiplexing signal is the high peak-to-average power ratio. Therefore, it is important to minimize the peak-to-average power ratio in the visible light communication systems more than in radio-frequency wireless applications. In the visible light communication systems, the high peak-to-average power ratio produces a high DC bias which reduces power efficiency of the system. A discrete Fourier transform spread orthogonal frequency division multiplexing is proposed to be used in wireless communication systems; its ability to minimize peak-to-average power ratio has been tested. The analysis of two different subcarrier allocation methods for the discrete Fourier transform-spread subcarriers, as well as the examination of two distinct subcarrier allocation strategies, distributed and localized mapping, are investigated and studied. The effects of an accurate new sub-band mapping for the localized discrete Fourier transform spread orthogonal frequency division multiplexing scheme are presented in this paper. The light-fidelity system performance of the orthogonal frequency division multiplexing and discrete Fourier transform spread orthogonal frequency division multiplexing with different sub-mapping techniques are simulated with Matlab™. A system performance size of bit error rate and peak-to-average power ratio are obtained, as well.
Źródło:
Opto-Electronics Review; 2021, 29, 4; 167--174
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physicochemical Assessment of the Biodegradability of Agricultural Nonwovens Made of PLA
Ocena fizykochemiczna biodegradowalności agrowłóknin wytworzonych z PLA
Autorzy:
Miros-Kudra, Partycja
Gzyra-Jagieła, Karolina
Kudra, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1419923.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
PLA agricultural nonwovens
degradability
compostability
gel chromatography
GPC
size exclusion chromatography
SEC
Fourier transform infrared spectroscopy
FTIR
agrowłóknina
degradowalność
kompostowalność
chromatografia żelowa
chromatografia wykluczania
spektroskopia w podczerwieni z transformacją Fouriera
Opis:
Compostable biodegradable plastics are an ecological alternative to traditional products based on petroleum derivatives, whose post-use waste may pollute the natural environment. Modern polymer materials show the functional properties of plastics obtained by conventional methods, but they also may be degraded as a result of biochemical transformations in composting. This allows such materials to be included in the scheme of the currently implemented circular economy, which does not generate post-consumer waste. This paper presents methods for the assessment of the biodegradation process of selected agricultural nonwovens produced from commercial PLA 6252D polylactide, supplied by Nature Works® LLC, USA. The agricultural nonwovens tested, obtained by the spun-bond technique, were characterised by different degrees of crystallinity in the range from 11.1% to 31.4%. Biodegradation tests were carried out as simulated aerobic composting while maintaining constant environmental conditions in accordance with test procedures based on PN-EN/ISO standards using the method of sample mass loss determination. Gel chromatography (GPC/SEC) and FTIR spectroscopy were also applied to assess the degree of biodegradation. The aim of this study was to evaluate the effect of the crystallinity of nonwoven made of PLA 6252 D on its degradation in a compost environment.
Kompostowalne tworzywa biodegradowalne są ekologiczną alternatywą dla tradycyjnych produktów opartych na pochodnych ropy naftowej, zalegających i zanieczyszczających środowisko naturalne w formie odpadów poużytkowych. Nowoczesne materiały polimerowe wykazują właściwości użytkowe tworzyw sztucznych otrzymywanych metodami konwencjonalnymi a ponadto ulegają utylizacji na drodze przemian biochemicznych w wyniku kompostowania. Pozwala to na wpisanie się takich materiałów w schemat obecnie pożądanej gospodarki cyrkularnej, która nie generuje odpadów poużytkowych. W niniejszej pracy przedstawiono metody badań biorozkładu wybranych agrowłóknin wytworzonych z komercyjnego polilaktydu PLA 6252D firmy Nature Works® LLC, USA. Badane agrowłókniny otrzymane techniką spun-bonded charakteryzowały się różnymi stopniami krystaliczności w zakresie od 11.1% do 31.4%. Badania biodegradacyjnie prowadzono w procesie symulowanego kompostowania aerobowego z zachowaniem stałych warunków środowiskowych zgodnie z procedurami badawczymi na podstawie norm PN-EN/ISO z wykorzystaniem metody wyznaczania ubytku masy. Do oceny stopnia biodegradacji zastosowano również technikę chromatografii żelowej (GPC/SEC) oraz spektrofotometrię FTIR. Celem pracy było określenie wpływu krystaliczności włóknin wytworzonych z PLA 6252 D na rozkład w środowisku kompostowym.
Źródło:
Fibres & Textiles in Eastern Europe; 2021, 1 (145); 26-34
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radial internal clearance analysis in ball bearings
Autorzy:
Ambrożkiewicz, Bartłomiej
Syta, Arkadiusz
Meier, Nicolas
Litak, Grzegorz
Georgiadis, Anthimos
Powiązania:
https://bibliotekanauki.pl/articles/1841795.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
ball bearings
radial internal clearance
statistical analysis
recurrence
fast fourier transform
continuous wavelet transform
Opis:
Radial internal clearance (RIC) is one of the most important parameters influencing on rolling bearing exploitation in mechanical systems. Lifetime of rotary machines strongly depends on a condition of applied rolling elements, thus a study on applied clearance is very important in terms of maintenance and reliability. This paper proposes, a novel approach of studying RIC, based on a nonlinear dynamics method called recurrences. The results are confronted with standard analyses, i.e. statistical condition indicators, Fast Fourier Transform and Continuous Wavelet Transform. The application of the mentioned methods allowed us to find the optimal radial clearance for operating bearings. To ensure precise measurements of the clearance, an automated setup for RIC measurements is applied and next mounted in a plummer block and tested to finally measure vibration acceleration. The proposed methods are useful for a condition monitoring and lifetime prediction of bearings or bearing-based systems in which a proper value of radial clearance is crucial.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 1; 42-54
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sprawdzenie możliwości wykorzystania potencjału mikroskopii IR w branży naftowej
Checking the possibility of using the potential of IR microscopy in the petroleum industry
Autorzy:
Wieczorek, Agnieszka
Sroczyńska, Dagmara
Powiązania:
https://bibliotekanauki.pl/articles/2143571.pdf
Data publikacji:
2021
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
mikroskopia IR
spektrometria w podczerwieni z transformacją Fouriera (FT-IR)
mikroskopia
produkty naftowe
IR microscopy
Fourier transform infrared spectrometry (FT-IR)
microscopy
petroleum products
Opis:
Mikroskopia w podczerwieni z transformacją fourierowską (FT-IR) wykorzystuje dwie techniki badawcze: mikroskopię i spektrometrię FT-IR. Pozwala to na analizę materiału pod kątem występowania charakterystycznych grup funkcyjnych oraz na przedstawienie jego topograficznego rozkładu. Daje to możliwość analizy związków chemicznych w mikroobszarach badanego materiału. Przegląd literatury wskazuje na szerokie zastosowanie tych połączonych technik, m.in. w diagnostyce medycznej, kryminalistyce czy w badaniu jednorodności analitów. Analizie poddawane są tkanki, a także pojedyncze komórki. Wśród zalet połączonych technik jako narzędzia diagnostycznego należy wymienić możliwość rejestracji anomalii składu chemicznego z mikrometrową rozdzielczością przy minimalnej preparatyce, próbki nie wymagają dodatkowego utrwalania materiału do badań ani stosowania żadnych markerów. Niniejszy artykuł ma na celu przedstawienie przykładowych możliwości zastosowania mikroskopii IR w pracy laboratorium naftowego, podczas badania próbek ciekłych oraz stałych w postaci zawiesin czy osadów wytrąconych na elementach zbiorników, silników i różnych urządzeń. Wskazano na konieczność właściwego przygotowania próbek w zależności od ich charakteru oraz rodzaju zastosowanej techniki. Pokazano też możliwości związane z posiadanymi bibliotekami widm oraz mapowania po wybranym obszarze widm. Należy jeszcze raz wskazać na istotną rolę, jaką pełni mikroskopia FT-IR w badaniu próbek niejednorodnych, głównie ze względu na możliwość wytypowania konkretnych punktów pomiarowych o większej koncentracji substancji organicznych w stosunku do obszarów z dużą koncentracją, np. wody. Dzięki temu można w prostszy sposób określać, czy dana substancja lub produkt występujący w miejscu poboru wpływa na powstawanie osadów lub emulsji. Mikroskopia IR umożliwia przede wszystkim prowadzenie analizy niewielkiej ilości próbki, co jest szczególnie ważne w badaniu pobranych substancji w śladowych ilościach.
Fourier transform infrared microscopy (FTIR) uses two research techniques: microscopy and FTIR spectrometry. This allows to analyze fragments in terms of specific functional groups and the presentation of its topographic distribution. It enables the analysis of test results in the micro-areas of the tested material. IR microscopy is a technique that brings many advantages, mainly when it comes to examining samples with heterogeneous composition and surface. Thanks to it, it is possible not only to analyze small sample areas, but also to distinguish individual substances or groups of bonds present in them. During the test, the analyst can check both the homogeneity of the sample and the specific areas in which its composition changes. Due to this variety of applications, this technique is widely used in medicine, as well as in environmental research, forensics, and the research in the oil industry discussed in this article. The aim of the article is to present examples of the possibilities of applying the described technique in the work of an oil laboratory. It should be pointed out once again that this is of great importance, especially in FTIR microscopy when sampling heterogeneous samples, due to the possibility of selecting measurement point results for additional concentrations of organic compounds compared to areas with, for example, water. This makes it easier to determine whether a given substance or product is initially affecting the sediment or emulsion. Above all, IR microscopy allows a small amount of sample to be analyzed, which is particularly important when examining the collected substances in trace amounts.
Źródło:
Nafta-Gaz; 2021, 77, 9; 613-620
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, spectroscopic and thermogravimetric interpretations of UO2(II), ZrO(II), Zr(IV), VO(II) and V(V) ciprofloxacin antibiotic drug complexes
Autorzy:
Albedair, Lamia A.
Powiązania:
https://bibliotekanauki.pl/articles/1849331.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
ciprofloxacin
complexation
FTIR
Fourier transform infrared spectroscopy
diamagnetic
TEM
transmission electron microscopy
nanoscale
Opis:
New five ciprofloxacin (CIP) complexes of dioxouranium(II), oxozirconium(II), zirconium(IV), oxovanadium(II) and vanadium(IV) in the proportion 1:2 have been prepared using CIP as a drug chelate with UO2(NO3)2. 6H2O, ZrOCl2. 8H2O, ZrC4, VOSO4. xH2O and V2O5 respectively. The CIP complexes have been characterized based on the elemental analysis, molar conductance, magnetic, (FTIR & 1HNMR) spectral and thermal studies. The molar conductance studies of the synthesized complexes in DMSO solvent with concentration of 10–3 M indicate their non-electrolytic properties. At room temperature, the magnetic moment measurements revealed a diamagnetic behavior for all CIP prepared complexes. The different formulas of the new complexes can be represented as [UO2(CIP)2(NO3)2] (I), [VO(CIP)2(SO4)(H2O)] (II), [V2(O)(O2)2(CIP)2] (III), [Zr(O)(CIP)2(Cl)2] (IV), and [Zr(CIP)2(Cl)4] (V). The thermal analysis data of the complexes indicates the absence of coordinated water molecules except for vanadyl(II) complex (II). The CIP chelate is a uni-dentate ligand coordinated to the mentioned metal ion through terminal piperazinyl nitrogen. The transmission electron microscopy (TEM) investigation confirms the nano-structured form of the complexes.
Źródło:
Polish Journal of Chemical Technology; 2021, 23, 1; 45-52
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
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:
The method of obtaining the spectral characteristics of the scanning probe microscope
Sposób uzyskania charakterystyki widmowej sondy skanującej mikroskopu
Autorzy:
Kataieva, Mariia
Kvasnikov, Vladimir
Powiązania:
https://bibliotekanauki.pl/articles/2174702.pdf
Data publikacji:
2021
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
nano-measurement
digital signal processing
scanning probe microscope
Fourier transform
nano-pomiar
cyfrowe przetwarzanie sygnału
mikroskop z sondą skanującą
transformata Fouriera
Opis:
The article discusses methods and algorithms for digital processing and filtering when carrying out nano-measurements using a scanning probe microscope. The paper discusses frequency methods for improving images, in particular, the use of the Fourier transforms with various filtering methods to improve the quality of the resulting image. Stable computational algorithms have been developed for transforming discrete signals based on the Fourier transform. Methods for the interpretation of the numerical results of the discrete Fourier transform in such packages as Matlab, MathCad, Matematica are presented. It is proposed to use a window transform, developed based on the Fourier transform, which makes it possible to single out the informative features of the signal and to reduce the influence of the destabilizing factors that arise when processing signals from a scanning gold microscope in real conditions.
W artykule omówiono metody i algorytmy cyfrowego przetwarzania i filtracji podczas nano-pomiarów z wykorzystaniem mikroskopu z sondą skanującą. Badane są metody korekcji częstotliwości obrazu, w szczególności wykorzystanie transformaty Fouriera z różnymi metodami filtracji w celu poprawy jakości otrzymanego obrazu. Opracowano stabilne algorytmy obliczeniowe do konwersji sygnałów dyskretnych na podstawie transformaty Fouriera. Przedstawiono metody interpretacji numerycznych wyników dyskretnej transformaty Fouriera w takich pakietach jak Matlab, MathCad, Matematica. Proponuje się zastosowanie transformacji okienkowej opracowanej na podstawie transformaty Fouriera, która pozwala wyodrębnić charakterystykę informacyjną sygnału i zmniejszyć wpływ czynników destabilizujących występujących podczas przetwarzania sygnału z mikroskopu z sondą skanującą w warunkach rzeczywistych.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2021, 11, 2; 52--55
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
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:
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:
Tricopter vibration analysis
Autorzy:
Popardovský, Vladimír
Ferenčák, Marek
Kriš, Tomáš
Tomaštík, Miroslav
Novotný, Lukáš
Powiązania:
https://bibliotekanauki.pl/articles/1840857.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
multicopter
vibrations
Fourier transform
vibration analysis
MATLAB
multikopter
drgania
transformata Fouriera
analiza drgań
Opis:
Unmanned Aerial Vehicle (UAV) is exposed to various types of stress during flight. One of the most significant negative influences is the vibrations produced by the rotating parts. If we assume a UAV of the multicopter type, it is a stress of the whole structure by vibrations produced by propulsion units, which are placed on symmetrically distributed arms. The propulsion unit consists of an electric-propeller assembly, with the propeller being the largest source of vibration. This is due to the uneven distribution of the mass with respect to its axis of rotation. In addition to the propeller, the rotating part is also the electric motor itself, although the electric motor contributes much less to the total vibrations than the propeller. For this reason, it is necessary to balance the propeller first statically and then dynamically balance the entire drive unit (engine + propeller). Our work is focused on vibration diagnostics of an experimental tricopter in order to optimize the power units - to produce the smallest possible vibrations.
Źródło:
Diagnostyka; 2021, 22, 3; 67-72
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tricopter vibration analysis
Autorzy:
Popardovský, Vladimír
Ferenčák, Marek
Kriš, Tomáš
Tomaštík, Miroslav
Novotný, Lukáš
Powiązania:
https://bibliotekanauki.pl/articles/1840875.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
multicopter
vibrations
Fourier transform
vibration analysis
MATLAB
multikopter
drgania
transformata Fouriera
analiza drgań
Opis:
Unmanned Aerial Vehicle (UAV) is exposed to various types of stress during flight. One of the most significant negative influences is the vibrations produced by the rotating parts. If we assume a UAV of the multicopter type, it is a stress of the whole structure by vibrations produced by propulsion units, which are placed on symmetrically distributed arms. The propulsion unit consists of an electric-propeller assembly, with the propeller being the largest source of vibration. This is due to the uneven distribution of the mass with respect to its axis of rotation. In addition to the propeller, the rotating part is also the electric motor itself, although the electric motor contributes much less to the total vibrations than the propeller. For this reason, it is necessary to balance the propeller first statically and then dynamically balance the entire drive unit (engine + propeller). Our work is focused on vibration diagnostics of an experimental tricopter in order to optimize the power units - to produce the smallest possible vibrations.
Źródło:
Diagnostyka; 2021, 22, 3; 67-72
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zagrożenia frakcją respirabilną krystalicznej krzemionki w przemysłowych procesach wysokotemperaturowych
Respirable fraction hazards of crystalline silica in high temperature industrial processes
Autorzy:
Surgiewicz, Jolanta
Pośniak, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/1845101.pdf
Data publikacji:
2021
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
respirabilna krystaliczna krzemionka
kwarc
krystobalit
spektrometria w podczerwieni z transformacją Fouriera (FT-IR)
przemysłowe stanowiska pracy
narażenie zawodowe
nauki o zdrowiu
inżynieria środowiska
respirable crystalline silica
quartz
cristobalite
Fourier transform-infrared spectrometry
industrial workplaces
occupational exposure
health sciences
environmental engineering
Opis:
W artykule przedstawiono wyniki badań dotyczące rozpoznania wielkości narażenia na krystaliczną krzemionkę występującą we frakcji respirabilnej w powietrzu na stanowiskach pracy w procesach odlewniczych. Badaniami objęto dziesięć stanowisk pracy w dwóch zakładach przemysłowych. Próbki powietrza pobierano za pomocą cyklonów umożliwiających pobranie z powietrza frakcji respirabilnej aerozolu. Krystaliczną krzemionkę oznaczano w powietrzu metodą spektrometrii w podczerwieni z transformacją Fouriera (FT-IR). Na badanych stanowiskach stwierdzono stężenia frakcji respirabilnej krzemionki przekraczające wartość normatywu higienicznego (NDS) wynoszącego w Polsce 0,1 mg/m3. Największe stężenia: 0,25 i 0,15 mg/m³ oznaczono w procesach przygotowania mas formierskich na stanowisku przerabiacza mas i czyszczenia form do odlewu oraz na stanowisku formierza maszynowego, jak również na stanowisku kadziowego pracującego przy przygotowaniu i obsłudze kadzi – 0,13 mg/m³. Stężenie frakcji respirabilnej w aerozolu krystalicznej krzemionki zależy od prowadzonego procesu z udziałem niezwiązanego piasku krzemowego i rodzaju wykonywanych czynności, w których powstaje duża ilość respirabilnego aerozolu, a także od natężenia prac wykonywanych na badanym stanowisku. Dla większości badanych stanowisk stwierdzono zagrożenie krystaliczną krzemionką na stanowiskach pracy. Wyniki badań wskazują na konieczność podjęcia środków zaradczych w celu eliminacji tego zagrożenia. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa i higieny środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu oraz inżynierii środowiska.
The article presents results of research on recognition of a size of crystalline silica exposure present in respirable fraction in the workplace air at high-temperature foundry processes. The study included 10 workplaces in two factories. Air samples collected with cyclones allowing the separation of respirable air. The crystalline silica was measured in air with Fourier transform infrared spectrometry (FT-IR). High concentrations of respirable fraction of silica, exceeding the value of the hygienic standard (NDS) of 0.1 mg/m3 in Poland, were found at the studied workplaces. The largest concentration of respirable crystalline silica (0.25 mg/m³ ) was found in the processes of sand preparation of transformer masses and processes of preparing forms on a position of aformer machine – 0.15 mg/m³ and on position of a sliding and pourer forms, at astand of machine moulder, at a stand of ladle maker during preparation and operation of ladles – 0.13 mg/m³ . The amount of respirable aerosol coagulation crystalline silica in high-temperature processes depends on a type of process and is especially present in stages involving unbound silica sand. It also differs in workflow steps and intensity performed on particular workplaces, where large amount of respirable aerosol is produced. Majority of examined workplaces are exposed to high risk of occurring crystalline silica in the respirable fraction. Research results indicate the need of implementing remedial measures to eliminate the hazard. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.
Źródło:
Podstawy i Metody Oceny Środowiska Pracy; 2021, 3 (109); 189-204
1231-868X
Pojawia się w:
Podstawy i Metody Oceny Środowiska Pracy
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:
Deblurring approach for motion camera combining FFT with α-confidence goal optimization
Autorzy:
Huang, Lve
Wu, Lushen
Xiao, Wenyan
Peng, Qingjin
Powiązania:
https://bibliotekanauki.pl/articles/174045.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image deblurring
fast motion camera
confidence goal optimization
fast Fourier transform
high-railway defect detection
Opis:
Sharp images ensure success in the object detection and recognition from state-of-art deep learning methods. When there is a fast relative motion between the camera and the object being imaged during exposure, it will necessarily result in blurred images. To deblur the images acquired under the camera motion for high-quality images, a deblurring approach with relatively simple calculation is proposed. An accurate estimation method of point spread function is firstly developed by performing the Fourier transform twice. Artifacts caused by image direct deconvolution are then reduced by predicting the image boundary region, and the deconvolution model is optimized by an α-confidence statistics algorithm based on the greyscale consistency of the image adjacent columns. The proposed deblurring approach is finally carried out on both the synthetic-blurred images and the real-scene images. The experiment results demonstrate that the proposed image deblurring approach outperforms the existing methods for the images that are seriously blurred in direction motion.
Źródło:
Optica Applicata; 2020, 50, 2; 185-198
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
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:
Experimental Comparative Investigations to Evaluate Cavitation Conditions within a Centrifugal Pump Based on Vibration and Acoustic Analyses Techniques
Autorzy:
Al-Obaidi, Ahmed Ramadhan
Powiązania:
https://bibliotekanauki.pl/articles/177056.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
centrifugal pump
cavitation
Fast Fourier Transform
vibration
acoustic
normalise features
Opis:
Cavitation is an essential problem that occurs in all kinds of pumps. This cavitation contributes highly towards the deterioration in the performance of the pump. In industrial applications, it is very vital to detect and decrease the effect of the cavitation in pumps. Using different techniques to analysis and diagnose cavitation leads to increase in the reliability of cavitation detection. The use of various techniques such as vibration and acoustic analyses can provide a more robust detection of cavitation within the pump. In this work therefore, focus is put on detecting and diagnosing the cavitation phenomenon within a centrifugal pump using vibration and acoustic techniques. The results obtained from vibration and acoustic signals in time and frequency domains were analysed in order to achieve better understanding regarding detection of cavitation within a pump. The effect of different operating conditions related to the cavitation was investigated in this work using different statistical features in time domain analysis (TDA). Moreover, Fast Fourier Transform (FFT) technique for frequency domain analysis (FDA) was also applied. Furthermore, the comparison and evaluation system among different techniques to find an adequate technique incorporating for accuracy and to increase the reliability of detection and diagnosing different levels of cavitation within a centrifugal pump were also investigated.
Źródło:
Archives of Acoustics; 2020, 45, 3; 541-556
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:
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:
General concept of the EMG controlled bionic hand
Autorzy:
Pieprzycki, Adam
Król, Daniel
Powiązania:
https://bibliotekanauki.pl/articles/93068.pdf
Data publikacji:
2020
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
EMG
neural-network
machine-learning
Fourier transform
Hilbert-Huang transform
Hodgkin-Huxley model
sieć neuronowa
nauczanie maszynowe
przekształcenie Fouriera
transformacja Hilberta-Huanga
model Hodgkina-Huxleya
Opis:
The article presents a general concept of a bionic hand control system using multichannel EMG signal, being under development at present. The method of acquisition and processing of multi-channel EMG signal and feature extraction for machine learning were described. Moreover, the design of the control system implementation in the real-time embedded system was discussed.
Źródło:
Science, Technology and Innovation; 2020, 8, 1; 26-34
2544-9125
Pojawia się w:
Science, Technology and Innovation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification and classification of selected internal combustion engine inefficiency based on vehicle structure vibrations
Autorzy:
Prażnowski, Krzysztof
Mamala, Jarosław
Bieniek, Andrzej
Graba, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/2146621.pdf
Data publikacji:
2020
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
short-term analysis
Fourier transform
engine diagnostics
diagnostic matrix
analiza krótkoterminowa
transformacja Fouriera
diagnostyka silnika
macierz diagnostyczna
Opis:
The combustion engine generates forced vibrations, caused by periodically acting external forces resulting from the combustion of the fuel-air mixture. Any changes in this process cause an increase in the value of vibration amplitude and a change in the distribution of harmonics dominating in the frequency domain. In order to identify selected malfunctions of the internal combustion engine of the Polaris off-road vehicle tested, its current parameters were correlated with the vibrations transmitted to the vehicle's structural elements. An integrated sensor for measuring acceleration using the direct method, made in MEMS technology, was used for the tests. The recorded signals of the acceleration components were subjected to analysis in the frequency domain, thus identifying the characteristic harmonic components in the analyzed spectrum. For the classification of incompleteness based on registered signals, a diagnostic inference matrix based on our own algorithm of conduct was used.
Źródło:
Vibrations in Physical Systems; 2020, 31, 1; art. no. 2020110
0860-6897
Pojawia się w:
Vibrations in Physical Systems
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:
Influence of thermal treatment on selected properties of chestnut wood and full range of its visual features
Autorzy:
Lo Monaco, Angela
Pelosi, Claudia
Agresti, Giorgia
Picchio, Rodolfo
Rubino, Gianluca
Powiązania:
https://bibliotekanauki.pl/articles/342665.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
Castanea sativa Mill.
heat treatment
colour
surface properties
reflectance spectrophotometry
Fourier Transform Infrared spectroscopy
Opis:
The use of chestnut wood (Castanea sativa Mill.) is highly relevant in Central Italy, as it is one of the most important and abundant broad-leaf species in this geographical area. The comprehension of the modifications induced by thermal treatment is of crucial importance to define the optimal temperature that could improve the mechanical and physical properties without affecting significantly the visual appearance. In this paper a careful and complete investigation on the effect of thermal treatment on chestnut wood (Castanea sativa Mill.) is reported. The aim of this study is addressed to understand the chemical-physical modifications occurred on the surface of wood samples, as a consequence of heating, in order to choose the most suitable temperature of treatment, also in the view of applying a possible coating. No such complete and homogeneous study on chestnut wood was found in the literature, so this paper contributes to add relevant scientific and technological information on it. Samples of chestnut were thermally treated 6 hours in a conventional oven at 140°C, 170°C and 200°C. Surface properties of heated wood, in comparison with untreated, were evaluated through the measurements of: roughness, colour, Vickers and Brinell hardness, surface profile and contact angle. The behaviour of earlywood and latewood was evaluated by studying separately the effect of heating on contact angle and surface micro- -hardness. Fourier transform infrared spectroscopy was also used to evaluate the chemical modification of wood components due to thermal treatment. Heating at 140°C has little influence on wood characteristics whereas 200°C has a great impact on colour, mechanical properties and hydrophobicity behaviour. The intermediate temperature, i.e. 170°C, seems to give the best results in term of improved mechanical properties and also aesthetical appearance of wood surfaces.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2020, 62, 205; 5-24
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena zanieczyszczenia powietrza na podstawie zdjęcia wiązki lasera
The analysis of air pollution based on laser beam photo
Autorzy:
Pawelec, Anna
Maksim, Rafał
Skublewska-Paszkowska, Maria
Powiązania:
https://bibliotekanauki.pl/articles/98146.pdf
Data publikacji:
2020
Wydawca:
Politechnika Lubelska. Instytut Informatyki
Tematy:
air pollution
Android
OpenCV
image processing
Fourier Transform
zanieczyszczenie powietrza
przetwarzanie obrazów
Transformata Fouriera
Opis:
The article presents a comparison of original methods of air quality measurement with a professional device Air Smart-box v. 1.2. The methodology consisted of laser beam analysis from the device. To enable detailed photo analysis for the research, an Android mobile application was developed. The OpenCV library was used to process the images. In the article, the hypothesis was put forward that the method using a binary threshold with a threshold value of 50 allows to obtain results closest to those of the station. This hypothesis was confirmed by the results of the experiments.
Artykuł przedstawia porównanie autorskich metod pomiaru jakości powietrza z profesjonalnym urządzeniem Air Smartbox v. 1.2. Metody polegają na analizie zdjęć wiązki lasera w zanieczyszczonym powietrzu. W celu przeprowa-dzenia badań została zaimplementowana aplikacja mobilna, dedykowana na system operacyjny Android, która umożliwia wykonanie zdjęć oraz ich późniejszą obróbkę i analizę. Do przetwarzania obrazów zastosowano bibliotekę OpenCV. W artykule postawiono hipotezę, że metoda wykorzystująca progowanie binarne z wartością progowania wynoszącą 50 pozwala uzyskać wyniki najbardziej zbliżone do wyników ze stacji. Hipoteza ta została potwierdzona uzyskanymi wynikami badań.
Źródło:
Journal of Computer Sciences Institute; 2020, 16; 317-325
2544-0764
Pojawia się w:
Journal of Computer Sciences Institute
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:
Synthesis of citrates of selected lanthanides (Er, Ho and Lu)
Autorzy:
Janusz, Władysław
Pikus, Stanisław
Skwarek, Ewa
Olszewska, Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/1450220.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
PXRD diffraction
Powder X-Ray Diffraction
FTIR
Fourier Transform Infrared
Er
Erbium
Ho
Holmium
Lu
Lutetium
citrates of Er
citrates of Ho
citrates of Lu
Opis:
Holmium, erbium and lutetium citrates can be synthesized by transforming freshly precipitated holmium, erbium and lutetium hydroxides in the citric acid solution under the hydrothermal conditions (above 100 ℃) after 3 days of reaction. In this paper in order to determine the synthesis conditions, the hydroxide and citrate stability areas of selected lanthanides were compared. The studies of the structure of the obtained holmium citrate, erbium and lutetium samples showed that these compounds crystallize in a monoclinic system. The crystallite sizes determined by the HalderWagner method were 67.8 ± 8.0nm, 103.7 ± 4.5nm and 68.1 ± 4.2nm, respectively for the holmium citrate, erbium citrate and lutetium citrate samples. The shifts of the hydroxyl and carboxyl groups of citric acid in the FTIR spectrum indicate the interactions of both groups with holmium, erbium and lutetium cations. Then the obtained samples were subjected to the analysis of composition, and their particle size distribution was determined.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 225-234
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of vibrations in the vehicle with naturally aspirated and turbocharged gasoline engine
Autorzy:
Łoza, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/2097460.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
vehicle
vibration
engine
downsizing
fast Fourier transform
accelerometry
pojazd
drgania
silnik
szybka transformata Fouriera
akcelerometria
Opis:
In this paper, the author presents a study of vibrations in a passenger vehicle and the possible influence on driver’s body in the process of natural operation. The author describes the dependence of engine size and additional equipment as the possible primary source of the vibration variations and their further propagation in the entire vehicle structure. The analysis was performed on the passenger cars with naturally aspirated and turbocharged gasoline engines. The aim of this study was to verify the level of vibrations in the vehicle structure with these particular engines, especially influence of downsized power unit, during various state of engine operation. The second goal was to examine the vibrations in the specified location related to driver’s body. The measuring method used piezoelectric accelerometers, which were attached to the designated locations in the vehicle and were able to detect variations of the acceleration. The signals were collected as characteristics in the time domain. In order to achieve frequency domain for spectral analyses, the author applied the Fast Fourier Transform (FFT).
Źródło:
Combustion Engines; 2020, 59, 2; 19--23
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of methods for obtaining nanocellulose using acid and ionic liquid hydrolysis reactions
Autorzy:
Babicka, Marta
Ratajczak, Izabela
Dwiecki, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/24072146.pdf
Data publikacji:
2019
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
1-butyl-3-methylimidazolium chloride
sulphuric acid(VI)
acid hydrolysis
ionic liquid hydrolysis
dynamic light scattering
fourier transform infrared spectroscopy
Opis:
A comparison of methods for obtaining nanocellulose using acid and ionic liquid hydrolysis reactions. In this study, two methods were compared, i.e. acid hydrolysis using sulphuric acid (VI) and ionic liquid hydrolysis using 1-methyl-3-butylimidazolium chloride to obtain nanocellulose from Sigmacell Cellulose Type 20. The efficiency of both processes was tested for weight loss of the material during the reaction. The study showed that much more material can be obtained using ionic liquid hydrolysis than using acid hydrolysis. A dynamic light scattering study was performed to determine material particle size before and after these processes. Particles of nanometric size were recorded only for cellulose after the reaction with an ionic liquid. In addition, Fourier transform infrared spectroscopy was performed to determine the chemical structure of the materials tested.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2019, 107; 19--23
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
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:
Badanie zawartości wybranych metali ciężkich w separatorze polimerowym akumulatora kwasowo-ołowiowego
Analysis of the selected heavy metals content in the lead-acid battery polymeric separator
Autorzy:
Kolasa, Dorota
Łukomska, Aneta
Sołtysiak, Joanna
Soszko, Michał
Ciężarek, Olga
Lach, Jakub
Wróbel, Kamil
Czerwiński, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/947358.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
separatory elektrod
polietylen
oznaczanie metali ciężkich
mineralizacja mikrofalowa
absorpcyjna spektrometria atomowa z atomizacją w płomieniu (FAAS)
analizator rtęci
skaningowa mikroskopia elektronowa/spektrometria dyspersji energii promieniowania rentgenowskiego (SEM/EDS)
spektroskopia w podczerwieni z transformacją Fouriera (FT-IR)
electrode separators
polyethylene
heavy metals determination
microwave-assisted digestion
flame atomic absorption spectrometry (FAAS)
mercury analyzer
scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS)
Fourier transform infrared spectroscopy (FT-IR)
Opis:
W materiale polimerowym stosowanym jako separator elektrod w akumulatorze kwasowo-ołowiowym oznaczano zawartość kadmu, ołowiu i rtęci. W kontekście obowiązujących przepisów dotyczących wprowadzanych do obrotu baterii i akumulatorów oraz przetwarzania zużytych baterii i zużytych akumulatorów porównano wyniki badania próbek separatora przed użyciem w procesach elektrochemicznych oraz próbek odpadowych. W badaniach separatora [poprzedzonych analizą jakościową tworzywa metodami: skaningowej mikroskopii elektronowej/spektrometrii dyspersji energii promieniowania rentgenowskiego (SEM/EDS) i spektroskopii w podczerwieni z transformacją Fouriera (FT-IR)] wykorzystano nowoczesny aparat do mikrofalowego roztwarzania próbek w połączeniu z techniką absorpcyjnej spektrometrii atomowej z atomizacją w płomieniu (FAAS) i analizatorem rtęci. Zastosowane procedury analityczne weryfikowano na podstawie wyników badania certyfikowanego materiału odniesienia (PE-LD) zawierającego śladowe ilości analitów.
Results of cadmium, lead and mercury determination in the polymeric material used as an electrode separator in the lead-acid battery have been presented. Samples of the separator before use in the electrochemical processes and the waste separator samples have been compared with reference to the existing laws on batteries and accumulators and waste batteries and accumulators. In the polymer separator examination [preceded by a qualitative analysis of the material using scanning electron microscopy/ energy dispersive X-ray spectrometry (SEM/EDS) and Fourier transform infrared spectroscopy (FT-IR) techniques], a modern UltraWAVE digestion system combined with flame atomic absorption spectrometry (FAAS) technique and a DMA-80 Direct Mercury Analyzer has been used. The quality of metal determination results has been evaluated using a certified PE-LD reference material containing trace amounts of analytes.
Źródło:
Polimery; 2019, 64, 6; 442-451
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete Fourier transform and permutations
Autorzy:
Hui, S.
Żak, S. H.
Powiązania:
https://bibliotekanauki.pl/articles/202022.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
discrete Fourier transform
DFT
DFT invariants
Fourier coefficients
permutations
DFT coefficient magnitudes
circulant matrix
pattern recognition
Opis:
It is well known that the magnitudes of the coefficients of the discrete Fourier transform (DFT) are invariant under certain operations on the input data. In this paper, the effects of rearranging the elements of an input data on its DFT are studied. In the one-dimensional case, the effects of permuting the elements of a finite sequence of length N on its Discrete Fourier transform (DFT) coefficients are investigated. The permutations that leave the unordered collection of Fourier coefficients and their magnitudes invariant are completely characterized. Conditions under which two different permutations give the same DFT coefficient magnitudes are given. The characterizations are based on the automorphism group of the additive group ZN of integers modulo N and the group of translations of ZN. As an application of the results presented, a generalization of the theorem characterizing all permutations that commute with the discrete Fourier transform is given. Numerical examples illustrate the obtained results. Possible generalizations and open problems are discussed. In higher dimensions, results on the effects of certain geometric transformations of an input data array on its DFT are given and illustrated with an example.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 6; 995-1005
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of an anomalous hollow beam with orbital angular momentum
Autorzy:
Lu, Xingyuan
Zhao, Chengliang
Hoenders, Bernhard J.
Yang, Yuanjie
Cai, Yangjian
Powiązania:
https://bibliotekanauki.pl/articles/173518.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anomalous hollow beam
orbital angular momentum
focused intensity
Fourier transform
Opis:
Anomalous hollow beam has potential applications in the optical trapping and free space optical communications, etc. It is noted that, thus far, although a large number of studies have been carried out in this field, most of them are theoretical studies and only quite a few cases have experimental results. Here, we experimentally study the generating of anomalous hollow beam carrying orbital angular momentum, and measure its topological charge. We show that the number of dark rings in the Fourier transform of intensity patterns is equal to the topological charge. The experimental results agree well with the simulations.
Źródło:
Optica Applicata; 2019, 49, 2; 217-226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fourier image methods for evolution equations of deep-water waves
Autorzy:
Jankowski, Jan
Leszczyński, Henryk
Powiązania:
https://bibliotekanauki.pl/articles/1955223.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska
Tematy:
wave evolution
Laplace equation
Fourier transform
method of lines
Gauss-Hermite quadrature
Opis:
The velocity potential of the fluid satisfies the Laplace equation with nonlocal boundary conditions on a free surface. This differential problem is transformed to an evolution equation in Fourier variables. The Fourier transform images of boundary functions are approximated by Picard's iterations and the method of lines on meshes related to roots of Hermite polynomials. Due to convolutions of sine and cosine functions the integral terms of Picard's iterations reveal unexpected instabilities for wave numbers in a neighborhood of zero.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2019, 23, 3; 261-268
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of Bee Colony Acoustic Signals using the Dynamic Time Warping Algorithm
Autorzy:
Polyniak, Yu.
Fedasyuk, D.
Marusenkova, Tetyana
Powiązania:
https://bibliotekanauki.pl/articles/972922.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
Acoustic Signal
Signal Recognition
Dynamic Time Warping
Fast Fourier Transform
Automated Bee Colony Monitoring
Opis:
The work deals with automated recognition of the current state of a bee colony, for continuous monitoring of processes running in a bee hive is of key importance in beekeeping. The dynamic time warping algorithm is considered as a method of analyzing acoustic signals produced by a bee colony. Upon such an analysis one can make inferences about the current state of the colony. We have developed a software module for audio-signal identification, which is to be used as a part of an automated bee colony monitoring system, and a software tool for verification of the module. We evaluated the efficacy of the algorithm, the probability of bee colony states correctly recognized using acoustic signals produced by the colony and consumed computational resources by the example of a queen bee’s sounds recorded during swarming. The dependencies of the signal processing time and the successful pattern recognition probabilities on the frame sample rate and frame size are presented.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2019, 8, 4; 19-27
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the internal combustion engine malfunctions based on the vibrations of the vehicle body
Autorzy:
Mamala, Jarosław
Prażnowski, Krzysztof
Graba, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/133120.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
vibrations
vehicle diagnostics
Fourier transform
drgania
diagnostyka pojazdu
transformacja Fouriera
Opis:
Selected parameters of an IC engine were correlated with vibrations transferred to the vehicle body with the aim of identifying engine malfunctions. Registered acceleration component signals were analyzed in the aspect of frequency. A reasoning model based on devised identification matrix was used to classify obtained data. This allowed the authors to estimate the possibility of research object damage/malfunctions with an assumed degree of probability.
Źródło:
Combustion Engines; 2019, 58, 4; 176-181
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
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:
Pricing European options in the variance gamma model
Autorzy:
Orzechowski, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/2147432.pdf
Data publikacji:
2019-06-03
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
European options
the variance gamma model
Fourier transform
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2019, 20, 1; 45-53
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Factorization of Integers 21 and 91 using Shor’s Algorithm
Autorzy:
Ardhyamath, Poornima
Naghabhushana, N. M.
Ujjinimatad, Rohitha
Powiązania:
https://bibliotekanauki.pl/articles/1070857.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Euclidean Algorithm
Factorization
GCD
Quantum Fourier Transform
Shor’s Algorithm
Opis:
In this paper we focused on the factorization of integer in detail using well known Shor’s algorithm and its quantum part realization. The algorithm finds prime factors any integer more efficiently than any known classical algorithm. It is based on prior knowledge of the answer to the factorization problem. Algorithm includes finding gcd using polynomial time Euclidean algorithm, determination of unknown period from quantum computer and continued fraction expansion approach. Factorization of two integers 21 and 91 are shown in this paper with all steps. Quantum part of the factorization described mathematically.
Źródło:
World Scientific News; 2019, 123; 102-113
2392-2192
Pojawia się w:
World Scientific News
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:
Analysis of broadband antenna radiation pulses
Badania anteny szerokopasmowego piramidalnego turbowego promiennika do niszczenia szkodników w glebach
Autorzy:
Cherenkov, A.
Hutsol, T.
Garasymchuk, I.
Pancyr, J.
Terenov, D.
Dubyna, V.
Powiązania:
https://bibliotekanauki.pl/articles/93987.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
antenna
electromagnetic energy emitter
Fourier transform
communicating wave
aperture
biotechnology
broadband pulses
antena
energia elektromagnetyczna
promiennik
transformacja Fouriera
transmisja fali
apertura
biotechnologia
impulsy szerokopasmowe
Opis:
Electromagnetic energy can alter metabolic and biosynthetic processes and under certain parameters of pulsed EMF it can change pulse repetition frequency, operation cycle, power, exposure, as well as it can slow down and inhibit cell growth. MW irradiation range of RNA and DNA - containing virus reduces their infectivity. Inhibition of bacterial cultures growth, changes in phagocytic activity of protein biosynthesis, ultrastructural changes in the cells when exposed to EMF EHF. It was found in experiments with micro-organisms that biological effects of EMF on microorganisms wore a resonant character. One of the basic mechanisms of inhibitory action of EHF radiation on harmful microorganisms is the role of membranes in biological reactions of microorganisms on the EMR.
Energia elektromagnetyczna może zmieniać procesy metaboliczne i biosyntezy oraz w pewnych parametrach pulsacyjnego pola elektromagnetycznego - częstość powtórzeń impulsu, cykl pracy, moc, ekspozycję, spowolnić i hamować wzrost komórkowy. Napromieniowanie w zakresie milimetrów RNA i DNA zawierających wirus prowadzi do zmniejszenia ich zakaźności. Hamowanie wzrostu bakteryjnych kultur, zmian aktywności fagocytowej, biosyntez białka, ultrastrukturalnych zmian w komórkach pod wpływem EMF w zakresie ultra-wysokiej częstotliwości. W eksperymentach z mikroorganizmami ustalono, że biologiczny wpływ działania pól elektromagnetycznych na mikroorganizmy był rezonansowy. Jednym z głównych mechanizmów hamowania promieniowania ultra-wysokiej częstotliwości na szkodliwe mikroorganizmy jest rola błon biologicznych w reakcjach mikroorganizmów na EMF. Istotne znaczenie mają zjawiska elektryczne występujące w biomembranach.
Źródło:
Agricultural Engineering; 2018, 22, 1; 15-28
2083-1587
Pojawia się w:
Agricultural Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the flame pulsation signals using a short-time Fourier transform
Analiza sygnałów pulsacji płomienia z wykorzystaniem krótkoczasowej transformaty Fouriera
Autorzy:
Grądz, Ż.
Powiązania:
https://bibliotekanauki.pl/articles/408519.pdf
Data publikacji:
2018
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
combustion process
short-time Fourier transform
flame pulsation
proces spalania
krótkoczasowa transformata Fouriera
pulsacja płomienia
Opis:
The main aim of the diagnostics of combustion process is ensuring its stability and efficiency. The most important aspect related to the monitoring of the combustion process is a non-invasive acquisition of information from flame and subsequently subjecting it for further processing. Such method of research allows to evaluate the course of the process and determine the characteristic conditions under which the combustion process is stable or not. The article presents the application of short-time Fourier transform for the analysis of flame pulsation signals. The aim of the research was to find an area especially sensitive to the change of combustion process conditions.
Głównym celem stawianym diagnostyce procesu spalania jest zapewnienie stabilności i efektywności przebiegu procesu. Najważniejszym aspektem monitorowania procesu spalania jest pozyskiwanie w sposób bezinwazyjny informacji z płomienia, a następnie poddanie jej dalszemu przetwarzaniu. Taki sposób badań pozwala na ocenę przebiegu procesu i daje możliwość wyznaczania charakterystycznych stanów, w których proces przebiega stabilnie lub nie. W artykule przedstawiono wykorzystanie krótkoczasowej transformaty Fouriera do analizy sygnałów pulsacji płomienia. Celem badań było znalezienie obszaru szczególnie wrażliwego na zmianę warunków w procesie spalania.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2018, 8, 3; 51-54
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Balance disturbances coefficient as a new value to assess ability to maintain balance on the basis of FFT curves
Autorzy:
Jurkojc, J.
Powiązania:
https://bibliotekanauki.pl/articles/307349.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
równowaga
stabilografia
szybka transformacja Fouriera
balance
stabilography
fast Fourier transform
coefficient
Opis:
The aim of this study was to formulate a new balance disturbances coefficient enabling objective balance assessment on the basis of fast Fourier transform curves. The article presents the method of coefficient calculation and possible ways of its interpretation. Methods: 11 healthy participants took part in the experiment. There were four measurements: two in real environment with eyes open and eyes closed as well as two in virtual environment with scenery (surroundings) oscillating with frequency 0.7 Hz and 1.4 Hz. Scenery was displayed by means of the Oculus Rift system, whereas position of centre of pressure was measured with the use of Zebris FDM-S platform. Obtained centre of pressure positions were used to calculate fast Fourier transform, and then balance disturbances coefficient. Results: Comparisons of coefficient values obtained for the whole group and two selected participants were presented in order to explain how to interpret and use the coefficient. For better explanation of coefficient interpretation the most popular time domain stabilometric quantities and fast Fourier transform curves were presented as well. Conclusions: The balance disturbances coefficient makes it possible to quantitatively and objectively determine, on the basis of fast Fourier transform curves, the influence of the oscillating scenery on the tested person as well as show how the overall equilibrium of that person was disturbed.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 1; 143-151
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Basic Aspects of Designing a High-performance Processor Structure for Calculating a "true" Discrete Fractional Fourier Transform
Autorzy:
Cariow, A.
Majorkowska-Mech, D.
Powiązania:
https://bibliotekanauki.pl/articles/114579.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
discrete fractional Fourier transform
parallelization of computations
hardware implementation
complexity reduction
Opis:
This paper presents a basic aspects of structural design of the highperformance processor for implementation of discrete fractional Fourier transform (DFrFT). The general idea of the possibility of parallelizing the calculation of the so-called “true” discrete Fourier transform on the basis of our previously developed algorithmic approach is presented. We specifically focused only on the general aspects of the organization of the structure of such a processor, since the details of a particular implementation always depend on the implementation platform used, while the general idea of constructing the structure of the processor remains unchanged.
Źródło:
Measurement Automation Monitoring; 2018, 64, 2; 43-45
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes of albumin secondary structure after palmitic acid binding : FT-IR spectroscopic study
Autorzy:
Oleszko, A
Hartwich, J.
Gąsior-Głogowska, M.
Olsztyńska-Janus, S.
Powiązania:
https://bibliotekanauki.pl/articles/307332.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kwas palmitynowy
albumina
spektrometria FTIR
palmitic acid
albumin
Fourier transform infrared spectroscopy
protein secondary structure
Opis:
Purpose: Albumin is an universal transport protein. Plasma pool of free fatty acids arising from triglyceride hydrolysis, critical in energy metabolism and etiology of metabolic disorders is transported by albumin. According to various studies albumin has from seven to nine binding sites with diverse affinity to long chain fatty acids. X-ray diffraction crystallography measurements have provided data only for pure human serum albumin or albumin with fully saturated binding sites. These results have shown that amount of -helices is higher after fatty acids binding. Molecular mechanics simulations suggest that binding of fatty acids in two high-affinity sites leads to major conformational changes in albumin structure. The aim of this research was to investigate albumin secondary structure upon gradually increasing fatty acids to protein mole ratio. Methods: Fourier transform infrared spectroscopy was applied to study changes of bovine serum albumin (as an analogue of human serum albumin) -helical structures after binding palmitic acid in a range of 0–20 palmitic acid: albumin molar ratios representing pure protein, partial, full saturation and excess binding sites capacity. Results: Amount of -helices was increasing along with the amount of palmitic acid: bovine serum albumin molar ratio and reached maximum value around 2 mol/mol. Conclusions: Our studies confirmed molecular mechanics simulations and crystallographic studies. Palmitic acid binding in two high-affinity sites leads to major structural changes, filling another sites only slightly influenced bovine serum albumin secondary structure. The systematic study of fatty acids and albumin interactions, using an experimental model mimicking metabolic disorders, may results in new tools for personalized nanopharmacotherapy.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 1; 59-64
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
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:
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:
Influences of operating parameters on dry ball mill performance
Autorzy:
Cayirli, S.
Powiązania:
https://bibliotekanauki.pl/articles/110047.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
conventional ball mill
particle size
surface area
grinding aid
fluidity index
Fourier Transform Infrared Spectroscopy
Opis:
The paper is aimed to investigate the influence of operating parameters on dry fine grinding of calcite in a laboratory scale conventional ball mill. Within the context, the influence of operating parameters such as mill speed, ball filling ratio, ball size distribution, powder filling ratio, grinding aid dosage and grinding time were studied. The results of grinding tests were evaluated based on the product particle size (d50, d80) and surface area (m2/kg). As a result of this study, optimum grinding test conditions determined to be 70% of Nc, J=0.35 for ball filling ratio, 40 mm (10%), 32 mm (10%), 20 mm (40%), 12 mm (40%) for ball size distribution, fc=0.125 for powder filling ratio, 2000 g/Mg for grinding aid dosage and 60 min for grinding time. After determining optimum grinding conditions, the influence of grinding aid dosage on powder fluidity was determined. The use of 2000 g/Mg grinding aid dosage had a greater fluidizing effect compared to the other dosages and no aid condition (0 g/Mg). The influence of grinding aid on dry fine grinding of calcite was also examined by Fourier Transform Infrared Spectroscopy (FTIR). FTIR measurements indicated that grinding aid was adsorbed on the ground calcite particles surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 751-762
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mean value theorems for solutions of linear partial differential equations with constant coefficients
Twierdzenie o wartości średniej dla rozwiązań liniowych równań różniczkowych o pochodnych cząstkowych o stałych współczynnikach
Autorzy:
Pokrovskii, Andrei V.
Trofymenko, Olga D.
Powiązania:
https://bibliotekanauki.pl/articles/699866.pdf
Data publikacji:
2018
Wydawca:
Łódzkie Towarzystwo Naukowe
Tematy:
mean value, linear partial differential operator, weak solution, Fourier-Laplace transform, distribution
wartość średnia liniowego operatora różniczkowego cząstkowego, słabe rozwiązanie, transformata Fouriera-Laplace’a, dystrybucja
Opis:
https://doi.org/10.26485/0459-6854/2018/68.2/1 Wykazujemy twierdzenie o wartości średniej, które charakteryzuje ciągłe słabe rozwiązania jednorodnych liniowych równań różniczkowych cząstkowych o stałych współczynnikach w obszarach euklidesowych. W twierdzeniu tym wartość średnia funkcji gładkiej względem zespolonej miary borelowskiej na pewnej elipsoidzie specjalnej postaci jest równa pewnej kombinacji liniowej jej pochodnych cząstkowych w środku tej elipsoidy. Główny wynik pracy uogólnia znane twierdzenie Zalcmana.
https://doi.org/10.26485/0459-6854/2018/68.2/1 We prove a mean value theorem that characterizes continuous weak solutions of homogeneous linear partial differential equations with constant coefficients in Euclidean domains. In this theorem the mean value of a smooth function with respect to a complex Borel measure on an ellipsoid of special form is equal to some linear combination of its partial derivatives at the center of this ellipsoid. The main result of the paper generalizes a well-known Zalcman’s theorem.
Źródło:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations; 2018, 68, 2; 13-24
1895-7838
2450-9329
Pojawia się w:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement accuracy verification of phasor measurement unit with dynamic phasor estimation
Autorzy:
Arendarski, B.
Rabe, S.
Heineken, W.
Komarnicki, P.
Powiązania:
https://bibliotekanauki.pl/articles/140719.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
discrete Fourier transform (DFT)
dynamic phasor
measurement accuracy
phasor measurement unit (PMU)
power system
Opis:
Power systems that are highly loaded, especially by a stochastic supply of renew- ables and the presence of storages, require dynamic measurements for their optimal control. Phasor measurement units (PMUs) can be used to capture electrical parameters of a power system. Standards on the PMU dynamic performance have been modified to incorporate their new dynamic mode of operation. This paper examines the PMU dynamic performance and proposes essential algorithms for measurement accuracy verification. Measurements of dynamic input signals, which vary in amplitude or frequency, were taken during au- tomated tests of two PMUs. The test results are presented and expounded with further recommendation for the performance requirements. This paper also presents and examines applied testing procedures with relevance to the specifications of the IEEE Standard for Synchrophasor C37.118.1™-2011 and its amendment C37.118.1a™-2014.
Źródło:
Archives of Electrical Engineering; 2018, 67, 3; 529--543
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance and stability analysis of series-cascaded, high-gain, interleaved boost converter for photovoltaic applications
Autorzy:
Prasanna Kumar, C.
Venugopal, N.
Powiązania:
https://bibliotekanauki.pl/articles/1193536.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
series cascade
interleaved boost converter
high gain
stability
fast Fourier transform
Opis:
Interleaved boost converters (IBCs) are cascaded in parallel in most of the applications. This novel approach connects IBC in series cascade. The IBC has an optimal operating duty cycle of 0.5. Normally, photovoltaic source voltage is low because of space constraints. In order to boost the source voltage, a conventional boost converter is replaced with series-cascaded IBC in this paper. The single-stage IBC also boosts the voltage to twice the input voltage. In the proposed converter, output voltage is about four times the input voltage with the same 0.5 duty cycle. A mathematical model is developed and simulated for the proposed work in MATLAB/Simulink platform. The output of the proposed circuit is analysed through fast Fourier transform to know the harmonic content due to the switching. The system is tested for stability with signal-flow graph modelling. The proposed work is realised using hardware and tested to validate the model.
Źródło:
Power Electronics and Drives; 2018, 3, 38; 85-97
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation, characterization and optimization of cross-linked fructosyltransferase aggregates for the production of prebiotic fructooligosaccharides
Autorzy:
Ademakinwa, A.N.
Ayinla, Z.A.
Omitogun, O.G.
Agboola, F.K.
Powiązania:
https://bibliotekanauki.pl/articles/81247.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fructosyltransferase
Aureobasidium pullulans
fructooligosaccharide
prebiotic
statistical optimization
scanning electron microscopy
X-ray spectroscopy
Fourier transform infrared spectroscopy
biotransformation
chemometric analysis
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2018, 99, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
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:
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:
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:
WYCENA ASYMETRYCZNYCH OPCJI LOGARYTMICZNYCH ZA POMOCĄ TRANSFORMATY FOURIERA
PRICING ASYMMETRIC LOGARITHMIC OPTIONS VIA FOURIER TRANSFORM
Autorzy:
Orzechowski, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/453007.pdf
Data publikacji:
2018
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
model F. Blacka i M. Scholesa
transformata Fouriera
asymetryczne opcje logarytmiczne
Black-Scholes model
Fourier transform
asymmetric logarithmic options
Opis:
Celem artykułu jest wycena europejskich opcji logarytmicznych o asymetrycznym profilu wypłaty. W ramach podejmowanej problematyki zaproponowane zostały trzy podejścia pozwalające określić wartość modelową analizowanych instrumentów pochodnych przy utrzymaniu założeń właściwych modelowi F. Blacka i M. Scholesa, tj. podejście martyngałowe, F. Blacka i M. Scholesa oraz bazujące na transformacie Fouriera. Ponadto, dokonano analizy szybkości i dokładności obliczeniowej uwzględnionych podejść do wyceny analizowanych derywatów.
"The aim of the article is to price European logarithmic options via Fourier transform. As a part of the subject metter, three approaches were proposed to determine theoretical value of the analyzed derivatives in the F. Black and M. Scholes setting, i.e. the martingale approach, F. Black and M. Scholes approach and the approach based on the Fourier transform. In addition, an analysis of the computational speed and accuracy of the valuations was carried out."
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2018, 19, 3; 238-250
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Analysis of Evolutionary Algorithms for Synthesis of Scanned Linear Array of Mutually Coupled Parallel Dipole Antennas
Autorzy:
Patidar, H.
Mahanti, G. K.
Muralidharan, R.
Powiązania:
https://bibliotekanauki.pl/articles/227212.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna array
comparative analysis
evolutionary algorithms
inverse fast Fourier transform
scanning
Opis:
This paper presents a comparative analysis of three evolutionary algorithms, namely, Backtracking Search Algorithm, Cuckoo Search Algorithm and Artificial Bee Colony Algorithms for synthesis of a scanned linear array of uniformly spaced parallel half wavelength dipole antennas. Here, antenna parameters, namely Side Lobe Level, reflection coefficient and wide null depth are taken into consideration for comparison between algorithms. In addition to it, statistical parameters, namely best fitness value, mean and standard deviation of the fitness values obtained from algorithms are compared. Mutual coupling that exists among the antenna elements is included in obtaining radiation patterns and the self-impedances along with the mutual impedances are calculated by induced Electro-Motive Force method. Two different examples are shown in this paper to validate the effectiveness of the utilized approach. Although, this approach is applied to a linear array of dipole antennas; this can be utilized for other array geometries as well.
Źródło:
International Journal of Electronics and Telecommunications; 2017, 63, 2; 151-157
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Approach to Spindle Radial Error Evaluation Using a Machine Vision System
Autorzy:
Kavitha, C.
Ashok, S. D.
Powiązania:
https://bibliotekanauki.pl/articles/220748.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
machine vision
circular hough transform
Fourier series
runout
spindle radial error
Opis:
The spindle rotational accuracy is one of the important issues in a machine tool which affects the surface topography and dimensional accuracy of a workpiece. This paper presents a machine-vision-based approach to radial error measurement of a lathe spindle using a CMOS camera and a PC-based image processing system. In the present work, a precisely machined cylindrical master is mounted on the spindle as a datum surface and variations of its position are captured using the camera for evaluating runout of the spindle. The Circular Hough Transform (CHT) is used to detect variations of the centre position of the master cylinder during spindle rotation at subpixel level from a sequence of images. Radial error values of the spindle are evaluated using the Fourier series analysis of the centre position of the master cylinder calculated with the least squares curve fitting technique. The experiments have been carried out on a lathe at different operating speeds and the spindle radial error estimation results are presented. The proposed method provides a simpler approach to on-machine estimation of the spindle radial error in machine tools.
Źródło:
Metrology and Measurement Systems; 2017, 24, 1; 201-219
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Synchrophasor Estimatioo Errors
Autorzy:
Łukowicz, M.
Cygan, S.
Powiązania:
https://bibliotekanauki.pl/articles/410593.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
synchrophasor estimation
dynamic phasor
Fourier transform
Taylor Fourier series
phase locked loop
dynamic filter
Opis:
This papers discusses the analytical analysis of the syochrophasor estimation employed in electrical systems. Short time Fourier trsnsform with the phase locked loop and Taylor Fourier series are analyzed for signals relating to different states which may occor in real power systems. The object is the accurate phasor estimation regardless of the shape of input signal, what for some signal types is cumbersome. As a result of active and reactive power disturbance in a power system, the frequency deviation and amplitude fluctuations may appear in power system signals. As a consequences of short circuits or overvoltages signal changes occur. Ibis leads to unacceptable errors in short time Fourier transform resulting from Fourier transform properties. This paper presents character of occurring errors and their consequences individually for any signal deviation.
Źródło:
Present Problems of Power System Control; 2017, 8; 5-22
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automatic Genre Classification Using Fractional Fourier Transform Based Mel Frequency Cepstral Coefficient and Timbral Features
Autorzy:
Bhalke, D. G.
Rajesh, B.
Bormane, D. S.
Powiązania:
https://bibliotekanauki.pl/articles/177599.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
feature extraction
Timbral features
MFCC
Mel Frequency Cepstral Coefficient
FrFT
fractional Fourier transform
Fractional MFCC
Tamil Carnatic music
Opis:
This paper presents the Automatic Genre Classification of Indian Tamil Music and Western Music using Timbral and Fractional Fourier Transform (FrFT) based Mel Frequency Cepstral Coefficient (MFCC) features. The classifier model for the proposed system has been built using K-NN (K-Nearest Neighbours) and Support Vector Machine (SVM). In this work, the performance of various features extracted from music excerpts has been analysed, to identify the appropriate feature descriptors for the two major genres of Indian Tamil music, namely Classical music (Carnatic based devotional hymn compositions) & Folk music and for western genres of Rock and Classical music from the GTZAN dataset. The results for Tamil music have shown that the feature combination of Spectral Roll off, Spectral Flux, Spectral Skewness and Spectral Kurtosis, combined with Fractional MFCC features, outperforms all other feature combinations, to yield a higher classification accuracy of 96.05%, as compared to the accuracy of 84.21% with conventional MFCC. It has also been observed that the FrFT based MFCC effieciently classifies the two western genres of Rock and Classical music from the GTZAN dataset with a higher classification accuracy of 96.25% as compared to the classification accuracy of 80% with MFCC.
Źródło:
Archives of Acoustics; 2017, 42, 2; 213-222
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł

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