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Tytuł:
Presentation of a Wavelet-Based Harmonic Model for Tidal Level Forecasting at Sabah and Sarawak
Autorzy:
Abubakar, Auwal Garba
Mahmud, Mohd Razali
Tang, Kelvin Kang Wee
Husaaini, Alhaji
Powiązania:
https://bibliotekanauki.pl/articles/1837991.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
harmonic analysis
harmonic constituents
sea water level
tidal prediction
wavelet-based harmonic
Opis:
The world’s tides are a result of the combined forces of celestial forces and centrifugal force exerted by the Earth Moon and the Sun acting on the water body, earth tides and the atmospheric tides. Harmonic analysis is the most popular and widely accepted method used for the processing and expression of tidal behaviour as well as its characteristics. Despite its strengths, harmonic analysis has a few drawbacks when short data are involved for long term prediction. However, to enhance the accuracy of the popular methodology of harmonic analysis (HA), this study presents a wavelet based harmonic model for tidal analysis and prediction. Six months of water level heights at four tide gauge stations in Sabah and Sarawak of Malaysia were employed. The results obtained agrees with the original data when a comparison was made. The root mean square error (RMSE) and Pearson correlation coefficient (r) are the statistical index tools applied to test the functioning of the model. The residual error is the deviation between the original data and the predicted data which was also computed in this study. The new wavelet based harmonic model improves the accuracy of prediction. Moreover, the model is efficient and feasible for tidal analysis and prediction.
Źródło:
Geomatics and Environmental Engineering; 2020, 14, 4; 5-23
1898-1135
Pojawia się w:
Geomatics and Environmental Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and analysis of cementless hip-joint system using functionally graded material
Autorzy:
Asiri, Saeed
Powiązania:
https://bibliotekanauki.pl/articles/2065758.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
functionally graded material
cementless hip-joint system
natural frequency
harmonic response
fatigue analysis
finite element analysis
modal analysis
odpowiedź harmoniczna
analiza zmęczeniowa
analiza elementów skończonych
analiza modalna
Opis:
Functionally Graded Materials (FGM) are extensively employed for hip plant component material due to their certain properties in a specific design to achieve the requirements of the hip-joint system. Nevertheless, if there are similar properties, it doesn’t necessarily indicate that the knee plant is efficiently and effectively working. Therefore, it is important to develop an ideal design of functionally graded material femoral components that can be used for a long period. A new ideal design of femoral prosthesis can be introduced using functionally graded fiber polymer (FGFP) which will reduce the stress shielding and the corresponding stresses present over the interface. Herein, modal analysis of the complete hip plant part is carried out, which is the main factor and to date, very few research studies have been found on it. Moreover, this enhances the life of hip replacement, and the modal, harmonic, and fatigue analysis determines the pre-loading failure phenomena due to the vibrational response of the hip. This study deals with the cementless hip plant applying the finite element analysis (FEA) model in which geometry is studied, and the femoral bone model is based in a 3D scan.
Źródło:
Archive of Mechanical Engineering; 2022, LXIX, 1; 129--146
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the piezoelectric thimble tactile device operating modes
Autorzy:
Bansevicius, R.
Dragasius, E.
Grigas, V.
Jurenas, V.
Mazeika, D.
Zvironas, A.
Powiązania:
https://bibliotekanauki.pl/articles/307079.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
skóra
wymuszenie harmoniczne
analiza elementów skończonych
tactile sensation
skin strain
harmonic excitation
finite element analysis
Opis:
A multifunctional device to transfer graphical or text information for blind or visually impaired is presented. The prototype using tactile perception has been designed where information displayed on the screen of electronic device (mobile phone, PC) is transferred by oscillating needle, touching the fingertip. Having the aim to define optimal parameters of the fingertip excitation by needle, the computational analysis of different excitation modes has been carried out. A 3D solid computational finite element model of the skin segment, comprising four main fingertip skin layers (stratum corneum, epidermis, dermis and hypodermis) was built by using ANSYS Workbench FEA software. Harmonic analysis of its stress–strain state under excitation with different frequency (up to 10000 Hz) and harmonic force (0.01 N), acting outer stratum corneum layer in normal direction at one, two or three points has been performed. The influence of the mode of dynamic loading of skin was evaluated (in terms of the tactile signal level) on the basis of the normal and shear elastic strain in dermis, where mechanoreceptors are placed. It is shown that the tactile perception of information, delivered by three vibrating pins, may be influenced by configuration of excitation points (their number and phase of loading) and the frequency of excitation.
Źródło:
Acta of Bioengineering and Biomechanics; 2014, 16, 3; 135-143
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of scaffolding harmonic excitation
Autorzy:
Bęc, Jarosław
Błazik-Borowa, Ewa
Szer, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/2204503.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
scaffolding
harmonic excitation
dynamic analysis
direct integration
rusztowanie
wzbudzenie harmoniczne
analiza dynamiczna
integracja bezpośrednia
Opis:
Scaffolding is equipment usually used at construction sites. A scaffolding structure is lightweight and made of elements used many times. The characteristics of scaffolding make it susceptible to dynamic actions present at the structure or occurring nearby. A scaffolding structure of medium size was subjected to analysis in this paper. The structure FEM model was loaded with single force harmonic excitation with various frequencies ranging from 1 Hz to 12 Hz applied in one of many selected points on the scaffolding façade. In the first step, natural frequencies and mode shapes of the analyzed structure were calculated. Then the full dynamic analysis was carried out to obtain maximum displacements of selected control points. The relation of excitation force frequency and location to the amplitudes of generated displacement was observed. It was found that low excitation frequencies close to the natural frequencies of the structure produced vibrations ranging to large areas of the scaffolding surface. Higher excitation frequencies are usually less propagated at the scaffolding but still may produce some discomfort to the structure users in the vicinity of the excitation force location. Scaffolding is equipment usually used at construction sites. A scaffolding structure is lightweight and made of elements used many times. The characteristics of scaffolding make it susceptible to dynamic actions present at the structure or occurring nearby. A scaffolding structure of medium size was subjected to analysis in this paper. The structure FEM model was loaded with single force harmonic excitation with various frequencies ranging from 1 Hz to 12 Hz applied in one of many selected points on the scaffolding façade. In the first step, natural frequencies and mode shapes of the analyzed structure were calculated. Then the full dynamic analysis was carried out to obtain maximum displacements of selected control points. The relation of excitation force frequency and location to the amplitudes of generated displacement was observed. It was found that low excitation frequencies close to the natural frequencies of the structure produced vibrations ranging to large areas of the scaffolding surface. Higher excitation frequencies are usually less propagated at the scaffolding but still may produce some discomfort to the structure users in the vicinity of the excitation force location.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 1; art. no. e144577
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalization of Linear Rosenstark Method of Feedback Amplifier Analysis to Nonlinear One
Autorzy:
Borys, A.
Zakrzewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/226780.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
weakly nonlinear amplifiers
nonlinear Rosenstark model
nonlinear distortion analysis
harmonic distortion
constitutive equations
Volterra series
Opis:
Generalization of Linear Rosenstark Method of Feedback Amplifier Analysis to Nonlinear One This paper deals with an extension of the Rosenstark’s linear model of an amplifier to a nonlinear one for the purpose of performing nonlinear distortion analysis. Contrary to an approach using phasors, our method uses the Volterra series. Relying upon the linear model mentioned above, we define first a set of the so-called amplifier’s constitutive equations in an operator form. Then, we expand operators using the Volterra series truncated to the first three components. This leads to getting two representations in the time domain, called in-network and input-output type descriptions of an amplifier. Afterwards, both of these representations are transferred into the multi-frequency domains. Their usefulness in calculations of any nonlinear distortion measure as, for example, harmonic, intermodulation, and/or cross-modulation distortion is demonstrated. Moreover, we show that they allow a simple calculation of the so-called nonlinear transfer functions in any topology as, for example, of cascade and feedback structures and their combinations occurring in single-, two-, nd three-stage amplifiers. Examples of such calculations are given. Finally in this paper, we comment on usage of such notions as nonlinear signals, intermodulation nonlinearity, and on identification of transfer function poles and zeros lying on the frequency axis with related real-valued frequencies.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 1; 48-60
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On In-Network and Other Types of Amplifier Descriptions for Nonlinear Distortion Analysis
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/226946.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
weakly nonlinear amplifiers
nonlinear distortion analysis
harmonic distortion
constitutive relations
Volterra series
Opis:
Basics of modelling analog weakly nonlinear amplifiers at higher frequencies for the purpose of nonlinear distortion analysis are addressed in this paper. First, the constitutive relation for this class of amplifiers, with the use of a Volterra series, is formulated. It is the basis for formulation and derivation of the so-called in-network and input-output type descriptions of an amplifier in the time domain, which are then transferred into the multi-frequency domains. Usefulness of the general models achieved, which were not published up to now in the literature, lies in the fact that they can be used for any topology in which the amplifier is incorporated and for any nonlinear distortion measure assumed. Some examples of calculations are given at the end of the paper for cascade and feedback topologies, and for harmonic distortion measure.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 2; 177-184
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On influence of feedback on harmonics in mildly nonlinear analog circuits
O wpływie sprzężenia zwrotnego na składowe harmoniczne w układach analogowych z małymi nieliniowościami
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/389850.pdf
Data publikacji:
2009
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydawnictwo PB
Tematy:
analiza zniekształceń harmonicznych
sprzężenie zwrotne
układy i systemy analogowe pracujące w zakresie tzw. małych nieliniowośc
wpływ sprzężenia zwrotnego na składowe harmoniczne wyższych rzędów
szereg Volterry
harmonic
distortion analysis
mildly nonlinear circuits and systems
feedback
influence of feedback on harmonics
Volterra series
Opis:
First, it is shown that applying the linear feedback increases the order of nonlinearity of the whole mildly nonlinear amplifier in comparison with that characterizing the amplifier without this feedback. Second, the impact of this fact on harmonics, which appear in the feedback amplifier driven by a single complex harmonic signal, is analyzed in detail. Finally, the associated model of the feedback amplifier is derived. It is shown that using this model, and only then, it is possible to interpret correctly the means of harmonic distortion calculations in weakly nonlinear amplifiers proposed by Palumbo and Pennisi in one of their recent papers.
W pracy pokazano, że zastosowanie liniowego sprzężenia zwrotnego w układzie wzmacniacza analogowego pracującego w zakresie tzw. małych nieliniowości powoduje zwiększenie rzędu nieliniowości wykazywanej przez ten wzmacniacz w porównaniu ze wzmacniaczem bez sprzężenia. Przeanalizowano wpływ powyższego zjawiska na składowe harmoniczne wyższych rzędów, powstające przy pobudzeniu wzmacniacza pojedynczym sygnałem harmonicznym. Ponadto wyprowadzono model stowarzyszony wzmacniacza ze sprzężeniem zwrotnym. Pokazano, że wykorzystując ten model, i tylko wtedy, można zinterpretować w sposób prawidłowy metodę obliczeń zniekształceń harmonicznych we wzmacniaczach analogowych pracujących w zakresie tzw. małych nieliniowości, która to została zaproponowana przez Palumbo i Pennisi w jednym z ich ostatnio opublikowanych artykułów.
Źródło:
Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy; 2009, 12; 5-20
1899-0088
Pojawia się w:
Zeszyty Naukowe. Telekomunikacja i Elektronika / Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of Phasors in Nonlinear Analysis
Autorzy:
Borys, A.
Zakrzewski, Z
Powiązania:
https://bibliotekanauki.pl/articles/226074.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
phasor
Volterra series
analysis of nonlinear AC circuits
harmonic distortion analysis of weakly nonlinear circuits
balance of harmonics
Opis:
In this paper, the well-known method of phasor analysis of linear ac circuits is extended in a rigorous mathematical way to nonlinear analysis. This fills the lack of such a theory in the literature. The results derived enable carrying out the needed corrections of some results published recently that regard harmonic distortion analysis of weakly nonlinear circuits.
Źródło:
International Journal of Electronics and Telecommunications; 2013, 59, 3; 219-228
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Armature MMF and electromagnetic performance analysis of dual three-phase 10-pole/24-slot permanent magnet synchronous machine
Autorzy:
Chen, Zhenfei
Xing, Ning
Ma, Hongzhong
Li, Zhixin
Li, Jiayu
Fan, Chenyang
Powiązania:
https://bibliotekanauki.pl/articles/2202550.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dual three-phase winding
fractional-slot
concentrated winding
permanent magnet synchronous machines (SCW-PMSMs)
MMF harmonic analysis
space harmonics
magnet eddy-current loss (ECL)
SVPWM voltage supply
Opis:
Fractional-slot concentrated-winding permanent magnet synchronous machines (FSCW-PMSMs) have a good prospect of application in the drive system of electric and hybrid electric vehicles. However, the armature magnetomotive force (MMF) of FSCWPMSM contains a large number of space harmonics, which induce large magnet eddycurrent loss (ECL). To solve this problem, a dual three-phase 10-pole and 24-slot winding layout is proposed.MMFharmonic analysis shows that the 1st, 7th and 17th space-harmonic winding factors of the proposed winding can be reduced by 100%, 87% and 87% respectively, compared with a dual three-phase 10-pole and 12-slot winding. Electromagnetic performances of the proposed machine under rated sinusoidal current supply and space vector pulse-width-modulated (SVPWM) voltage supply are investigated based on 2D finite-element analysis. It is shown that the proposed machine can meet the requirement of torque and efficiency in the full speed range. Especially, magnet ECL can be reduced greatly due to the reduction of the 7th and 17th space harmonics.
Źródło:
Archives of Electrical Engineering; 2023, 72, 1; 189--210
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Invariant operators on function spaces on homogeneous trees
Autorzy:
Cowling, Michael
Meda, Stefano
Setti, Alberto
Powiązania:
https://bibliotekanauki.pl/articles/965849.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
spherical functions
harmonic analysis
homogeneous trees
Źródło:
Colloquium Mathematicum; 1999, 80, 1; 53-61
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Data mining system for air quality monitoring networks
Autorzy:
Czechowski, P.
Badyda, A.
Majewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/204820.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air pollutants
data quality analysis
data mining
estimation
exploratory methods
harmonic
principal component analysis
statistical tests outliers
influential
leverage observations
analytical software system
programming
Eco Data Miner
EDM
Winsorized mean
Cook
Mahalanobis distance
DFITS
COVRATIO
Opis:
The use of quantitative methods, including stochastic and exploratory techniques in environmental studies does not seem to be sufficient in practical aspects. There is no comprehensive analytical system dedicated to this issue, as well as research regarding this subject. The aim of this study is to present the Eco Data Miner system, its idea, construction and implementation possibility to the existing environmental information systems. The methodological emphasis was placed on the one-dimensional data quality assessment issue in terms of using the proposed QAAH1 method - using harmonic model and robust estimators beside the classical tests of outlier values with their iterative expansions. The results received demonstrate both the complementarity of proposed classical methods solution as well as the fact that they allow for extending the range of applications significantly. The practical usefulness is also highly significant due to the high effectiveness and numerical efficiency as well as simplicity of using this new tool.
Źródło:
Archives of Environmental Protection; 2013, 39, 4; 123-147
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wind turbine harmonics caused by unbalanced grid currents
Autorzy:
Dettmann, K. D.
Schostan, S.
Schulz, D.
Powiązania:
https://bibliotekanauki.pl/articles/262590.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
AC machines
circuit analysis
current measurement
harmonic analysis
harmonic distortion
power system harmonics
power system measurements
sequences
wind energy
wind power generation
Opis:
For wind turbines that feed into public grids limits for voltage and current harmonics must be assured. To verify that the actual levels are valid, measurements are necessary. Problems can occur to determine which part of these harmonics has its origin in the wind turbine. It is shown that also harmonics which originally have zero sequences can be transferred over a delta-star-transformer, if the currents of the wind turbine are asymmetric due to unbalanced loads. Measurements in an existing wind turbine configuration are discussed, which confirm the described effects.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2007, 13, 2; 17-23
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical stress analysis of harmonic drive elements by BEM
Numeryczna analiza stanu naprężenia elementów przekładni falowej z wykorzystaniem MEB
Autorzy:
Folęga, P.
Powiązania:
https://bibliotekanauki.pl/articles/256595.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji - Państwowy Instytut Badawczy
Tematy:
koło podatne
przekładnia falowa
analiza naprężenia
metoda elementów brzegowych
MEB
flexspline
harmonic drive
stress analysis
boundary element method
Opis:
The paper presents an analysis of the influence of design features of the flexspline in a harmonic drive, such as the relative radial deformation wo/m, the relative coating thickness g/df, and the design features of the basic rack tooth profile, on stress values in the bottom lands of a toothed rim. In the analysis of the state of stress, the boundary element method (BEM) was applied.
W opracowaniu przeprowadzono analizę wpływu przyjętych rodzajów mechanicznych generatorów fali oraz cech konstrukcyjnych koła podatnego: względnej deformacji promieniowej wo/m i względnej grubości powłoki g/df na rozkłady naprężeń w dnie wrębu. Ponadto wykonano analizę wpływu wybranych cech konstrukcyjnych zarysu odniesienia na wartości naprężeń w dnach wrębów międzyzębnych wieńca zębatego. W przeprowadzonej analizie stanu naprężenia wykorzystano metodę elementów brzegowych (MEB).
Źródło:
Problemy Eksploatacji; 2009, 1; 85-92
1232-9312
Pojawia się w:
Problemy Eksploatacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie analizy harmonicznej do badania zmienności cen produktów rolnych
The Application of Harmonic Analysis to Examine the Variation in the Prices of Agricultural Products
Autorzy:
Gędek, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/1849657.pdf
Data publikacji:
2020-05-12
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II. Towarzystwo Naukowe KUL
Tematy:
analiza harmoniczna
szeregi czasowe
ceny rolne
harmonic analysis
temporal series
agricultural prices
Opis:
Harmonic analysis (spectral, Fourier) is especially useful to study the stochastic structure of the temporal series, for it does not require any apriori presuppositions with regards to its parameters. In the present study two temporal series have been analysed. They concerned weekly quotations of two agricultural products (wheat, piglets) from one market in the period of 8 years (416 observations). Harmonic analysis appeared to be a comfortable and effective tool by means of which to identify the structure of the series under study; the model built on the basis of this analysis permitted us to explain over 80% of variability in those series. Therefor we could formulate a conclusion that in the case of the two series the dominating role was is played by long-term cyclical fluctuations, clearer in the case of the prices for piglets. Now in the temporal series of the wheat prices the seasonal fluctuations are clearer.
Źródło:
Roczniki Nauk Społecznych; 2006, 34, 3; 303-322
0137-4176
Pojawia się w:
Roczniki Nauk Społecznych
Dostawca treści:
Biblioteka Nauki
Artykuł
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