Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "frequency model" wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-10 z 10
    Tytuł:
    Comparison of acoustical and optical zooplankton measurements using an acoustic scattering model: A case study from the Arctic frontal zone
    Autorzy:
    Szczucka, Joanna
    Błachowiak-Samołyk, Katarzyna
    Trudnowska, Emilia
    Hoppe, Łukasz
    Powiązania:
    https://bibliotekanauki.pl/articles/2046858.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Arctic
    Svalbard
    zooplankton
    high−frequency echosounding
    sound scattering model
    Źródło:
    Polish Polar Research; 2016, 37, 1; 67-88
    0138-0338
    2081-8262
    Pojawia się w:
    Polish Polar Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multivariable predictive control considering time delay for load-frequency control in multi-area power systems
    Autorzy:
    Daniar, S.
    Shiroei, M.
    Aazami, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/229223.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    load frequency control
    model predictive control
    time delay
    generation rate constraint
    Opis:
    In this paper, a multivariable model based predictive control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area interconnected power system. The proposed controller is designed to consider time delay, generation rate constraint and multivariable nature of the LFC system, simultaneously. A new formulation of the MPC is presented to compensate time delay. The generation rate constraint is considered by employing a constrained MPC and economic allocation of the generation is further guaranteed by an innovative modification in the predictive control objective function. The effectiveness of proposed scheme is verified through time-based simulations on the standard 39-bus test system and the responses are then compared with the proportional-integral controller. The evaluation of the results reveals that the proposed control scheme offers satisfactory performance with fast responses.
    Źródło:
    Archives of Control Sciences; 2016, 26, 4; 527-549
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fatigue Behavior and Mechanism of FV520B-I Owing to the Effect of Loading Frequency on the Fatigue Property in HCF and VHCF Regime
    Autorzy:
    Wang, J.
    Zhang, Y.
    Shi, B.
    Zhao, Q.
    Sun, Q.
    Zhang, Z.
    Lu, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/353784.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrahigh loading frequency
    FV520B-I
    fatigue strength
    fatigue conversion model
    Opis:
    Fatigue property of FV520B-I is affected by the ultrahigh loading frequency significantly, and the ultrasonic fatigue experimental data can’t be employed directly to analyze the fatigue failure in the actual remanufacturing engineering. However few theories about the effect of loading frequency on the fatigue property of FV520B-I has ever been proposed. In this paper, both ultrasonic experiment and conventional experiment are conducted out to obtain the fatigue data. The effect of loading frequency on the fatigue data distribution is discussed firstly, its fatigue limit declines with the increase of the loading frequency. Then the fracture surface observations are captured, the fatigue property and fatigue behavior mechanism of FV520B-I is examined by analyzing the fracture surface features, crack initiation and failure observations. A new material frequency correction factor is proposed and introduced to eliminate the influence of the loading frequency on the FV520B-I fatigue property. FV520B-I empirical fatigue life conversion model and fatigue strength conversion model are established with comprehensive use of a fitting algorithm based on the combination of experimental data and classic formula. A clear understand of the effect of loading frequency on the fatigue property of FV520B-I is novel and has an important significance in guaranteeing the accuracy of the actual fatigue analysis of FV520B-I in the remanufacturing engineering.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 1; 347-357
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Time-domain Windowing on Isolated Speech Recognition System Performance
    Autorzy:
    Ananthakrishna, Thalengala
    Anitha, H.
    Girisha, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2055228.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hidden Markov model
    HMM
    isolated speech recognition system
    ISR
    Kannada language
    mono-phone model
    Mel frequency cepstral coefficients
    MFCC
    Opis:
    Speech recognition system extract the textual data from the speech signal. The research in speech recognition domain is challenging due to the large variabilities involved with the speech signal. Variety of signal processing and machine learning techniques have been explored to achieve better recognition accuracy. Speech is highly non-stationary in nature and therefore analysis is carried out by considering short time-domain window or frame. In the speech recognition task, cepstral (Mel frequency cepstral coefficients (MFCC)) features are commonly used and are extracted for short time-frame. The effectiveness of features depend upon duration of the time-window chosen. The present study is aimed at investigation of optimal time-window duration for extraction of cepstral features in the context of speech recognition task. A speaker independent speech recognition system for the Kannada language has been considered for the analysis. In the current work, speech utterances of Kannada news corpus recorded from different speakers have been used to create speech database. The hidden Markov tool kit (HTK) has been used to implement the speech recognition system. The MFCC along with their first and second derivative coefficients are considered as feature vectors. Pronunciation dictionary required for the study has been built manually for mono-phone system. Experiments have been carried out and results have been analyzed for different time-window lengths. The overlapping Hamming window has been considered in this study. The best average word recognition accuracy of 61.58% has been obtained for a window length of 110 msec duration. This recognition accuracy is comparable with the similar work found in literature. The experiments have shown that best word recognition performance can be achieved by tuning the window length to its optimum value.
    Źródło:
    International Journal of Electronics and Telecommunications; 2022, 68, 1; 161--166
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling of synchronous generators for the analysis of frequency transients above 1 Hz/s
    Autorzy:
    Assenkamp, Alf
    Powiązania:
    https://bibliotekanauki.pl/articles/2135729.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    control system
    distributed energy systems
    frequency support
    generator model
    RoCoF
    synchronous generators
    synchronous machines
    Opis:
    Large synchronous generators are of high importance for the stability of power systems. They generate the frequency of the system and stabilize it in case of severe grid faults like trips of large in-feeders or loads. In distributed energy systems, in-feed via inverters will replace this generation in large parts. Modern inverters are capable of supporting grid frequency during severe faults by different means on the one hand. On the other hand, higher Rates of Change of Frequency (RoCoF) after incidents need to be accustomed by future systems. To be able to analyse the RoCoF withstand capability of synchronous or induction generators, suitable models need to be developed. Especially the control and excitation system model need enhancements compared to models proposed in standards like IEEE Std 421.5. This paper elaborates on the necessary modelling depth and validates the approach with example results.
    Źródło:
    Archives of Electrical Engineering; 2022, 71, 3; 687--700
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical models for the evaluation of natural vibration frequencies of thermo-modernized building walls
    Modele numeryczne do oceny częstotliwości drgań własnych ścian budynków po termomodernizacji
    Autorzy:
    Kuźniar, K.
    Zając, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/230919.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    model numeryczny
    termomodernizacja ścian
    częstotliwość drgań własnych
    metoda elementów skończonych
    MES
    numerical model
    thermo-modernized wall
    natural vibration frequency
    finite element method
    FEM
    Opis:
    As a result of the necessity to improve energy properties of prefabricated buildings, their thermo-modernizations are performed. In the paper various approaches to the modelling of prefabricated load bearing walls before and after thermo-modernization are presented. Simple one layer models with extra mass from ceilings and equivalent stiffness as well as multilayer ones are taken into consideration using the finite element method software. Values of the natural frequencies of the wall horizontal vibrations calculated using the various models, are compared. It was proved that even the very simple model with equivalent stiffness allows to compute natural vibration frequencies of wall with acceptable accuracy for engineering practice.
    W niniejszej pracy pokazano różne podejścia do modelowania prefabrykowanych ścian nośnych przed i po termomodernizacji. Wykorzystując metodę elementów skończonych rozważono proste, jednowarstwowe modele o zastępczej sztywności oraz modele wielowarstwowe. Porównywano częstotliwości ich poziomych drgań własnych. Rozważono wysoką, typową prefabrykowaną ścianę nośną systemu budownictwa prefabrykowanego WWP – 10.8m szerokości i 29.7m (11 kondygnacji x 2.7m) wysokości. Każda płyta prefabrykowana składa się z trzech warstw: nośnej, izolacji cieplnej i elewacyjnej. Dodatkowe warstwy wynikające z termomodernizacji tworzą: zbrojona zaprawa, styropian i siatka z włókien szklanych.
    Źródło:
    Archives of Civil Engineering; 2018, 64, 4/I; 3-14
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Instantaneous Frequency Estimation of Multi-Component Non- Stationary Signals using Fourier Bessel series and Time-Varying Auto Regressive Model
    Autorzy:
    Ravi Shankar Reddy, G.
    Rao, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/226382.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    basis functions
    Fourier-Bessel expansion
    instantaneous frequency
    multi component non stationary signal
    Time-varying Auto Regressive model
    Opis:
    In this paper, we propose a novel technique for Instantaneous frequency (IF) estimation of multi component non stationary signals using Fourier Bessel Series and Time-Varying Auto Regressive (FB-TVAR) model. In the proposed technique, the Fourier-Bessel (FB) expansion decomposes the multicomponent non stationary signal into a number of monocomponent signals and TVAR model is used to model each monocomponent signal. In TVAR modeling approach the time varying parameters are expanded as a linear combination of basis functions. In this paper, the TVAR parameters are expanded by a discrete cosine basis functions. The maximum likelihood estimation algorithm for model order selection in TVAR models is also discussed. The Instantaneous frequency (IF) is extracted from the time-varying parameters by calculating the angles of the estimation error filter polynomial roots. The estimation of the TVAR parameters of a multicomponent signal requires the inversion of a large covariance matrix, while the projected technique (FB-TVAR) requires the inversion of a number of comparatively small covariance matrices with better numerical stability properties. Simulation results are presented for three component discrete Amplitude and Frequency modulated (AM-FM)signal.
    Źródło:
    International Journal of Electronics and Telecommunications; 2015, 61, 4; 365-376
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mathematical modelling of the high frequency vibrations during cold rolling process
    Matematyczne modelowanie drgań wysokoczęstotliwościowych występujących podczas walcowania blach na zimno
    Autorzy:
    Świątoniowski, A.
    Bar, O.
    Powiązania:
    https://bibliotekanauki.pl/articles/351698.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    rolling stand
    self-excited vibrations
    high-frequency vibrations
    Timoshenko beam mode
    walcowanie blach
    drgania samowzbudne
    drgania wysokoczęstotliwościowe
    model wiązki Timoshenko
    Opis:
    The study explores the model of high-frequency vibrations during the continuous rolling processes, the underlying assumption being that vibrations are self-excited. The effects of rolling stand and rolling process parameters on the nature and intensity of vibrations are investigated. The appearance of darkened streaks occurring on the metal sheet is explained. The results are compared with the data quoted in literature on the subject.
    W pracy przedstawiono model opisujący drgania o wysokiej częstości, występujące w trakcie ciągłego walcowania blach. Model ten jest oparty na założeniu samowzbudności procesu. Zbadano wpływ parametrów klatki oraz procesu walcowania na charakter i intensywność drgań. Wyjaśniono również zjawisko powstawania na powierzchni blachy zaciemnionych pasków. Otrzymane wyniki porównano z wynikami badań.
    Źródło:
    Archives of Metallurgy and Materials; 2013, 58, 4; 1085-1091
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling of non-linear losses in an integrated contactless power supply for magnetically levitated elevator systems using discrete circuit elements
    Autorzy:
    Putri, A. K.
    Appunn, R.
    Hameyer, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/141742.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    contactless energy transmission
    electromagnetic guiding system
    equivalent circuit model
    ferromagnetic material at high frequency
    magnetically levitated elevator
    modelling of non-linear losses
    Opis:
    A contactless energy transmission system is essential to supply onboard systems of electromagnetically levitated vehicles without physical contact to the guide rail. One of the possibilities to realise a contactless power supply (CPS) is by integrating the primary actuator into the guide rail of an electromagnetic guiding system (MGS). The secondary actuator is mounted on the elevator car. During the energy transmission, load dependent non-linear losses occur in the guide rail. The additional losses, which are caused by the leakage flux penetrating into the guide rail, cannot be modelled using the classical approach of iron losses in the equivalent circuit of a transformer, which is a constant parallel resistance to the mutual inductance. This paper introduces an approach for modelling the load dependent non-linear losses occurring in the guide rail using additional variable discrete circuit elements.
    Źródło:
    Archives of Electrical Engineering; 2015, 64, 2; 177-187
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An approach to suppress high-frequency resonance using model predictive and selective harmonic elimination combined strategy
    Autorzy:
    Chen, Sitong
    Chen, Xiaoqiang
    Wang, Ying
    Xiong, Ye
    Powiązania:
    https://bibliotekanauki.pl/articles/1841300.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    CRH5 EMUs and traction power supply coupled system
    high-frequency oscillation
    high speed railway
    model predictive control (MPC)
    selective harmonic elimination pulse-width modulation (SHEPWM)
    CRH5 EMU i system sprzężony z zasilaniem trakcyjnym
    oscylacja wysokiej częstotliwości
    kolej dużych prędkości
    kontrola predykcyjna modelu (MPC)
    selektywna eliminacja harmoniczna modulacja szerokości impulsu (SHEPWM)
    Opis:
    High-frequency resonance is a prominent phenomenon which affects the normal operation of the high-speed railway in China. Aiming at this problem, the resonance mechanism is analyzed first. Then, model predictive control and selective harmonic elimination pulse-width modulation (MPC-SHEPWM) combined control strategy is proposed, where the harmonics which cause the resonance can be eliminated at the harmonic source. Besides, the MPC is combined to make the current track the reference in transients. The proposed control has the ability to suppress the resonance while has a faster dynamic performance comparing with SHEPWM. Finally, the proposed MPC-SHEPWM is tested in a simulation model of CRH5 (Chinese Railway High-speed), EMUs (electric multiple units) and a traction power supply coupled system, which shows that the proposed MPC-SHEPWM approach can achieve the resonance suppression and shows a better dynamic performance.
    Źródło:
    Archives of Electrical Engineering; 2021, 70, 2; 415-430
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies