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    Wyświetlanie 1-13 z 13
    Tytuł:
    Investigation of the statistical method of time delay estimation based on conditional averaging of delayed signal
    Autorzy:
    Kowalczyk, A.
    Hanus, P.
    Szlachta, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/220429.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    time delay estimation
    random signals
    conditional averaging
    cross-correlation
    Opis:
    This paper presents the results of the theoretical and practical analysis of selected features of the function of conditional average value of the absolute value of delayed signal (CAAV). The results obtained with the CAAV method have been compared with the results obtained by method of cross correlation (CCF), which is often used at the measurements of random signal time delay. The paper is divided into five sections. The first is devoted to a short introduction to the subject of the paper. The model of measured stochastic signals is described in Section 2. The fundamentals of time delay estimation using CCF and CAAV are presented in Section 3. The standard deviations of both functions in their extreme points are evaluated and compared. The results of experimental investigations are discussed in Section 4. Computer simulations were used to evaluate the performance of the CAAV and CCF methods. The signal and the noise were Gaussian random variables, produced by a pseudorandom noise generator. The experimental standard deviations of both functions for the chosen signal to noise ratio (SNR) were obtained and compared. All simulation results were averaged for 1000 independent runs. It should be noted that the experimental results were close to the theoretical values. The conclusions and final remarks were included in Section 5. The authors conclude that the CAAV method described in this paper has less standard deviation in the extreme point than CCF and can be applied to time delay measurement of random signals.
    Źródło:
    Metrology and Measurement Systems; 2011, 18, 2; 335-342
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of sine-wave frequency estimation methods in respect of speed and accuracy for a few observed cycles distorted by noise and harmonics
    Autorzy:
    Borkowski, J.
    Kania, D.
    Mroczka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/220583.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    DFT spectrum interpolation
    short-time frequency estimation
    statistical analysis
    Prony LS
    TLS
    ESPRIT
    Opis:
    The paper deals with frequency estimation methods of sine-wave signals for a few signal cycles and consists of two parts. The first part contains a short overview where analytical error formulae for a signal distorted by noise and harmonics are presented. These formulae are compared with other accurate equations presented previously by the authors which are even more accurate below one cycle in the measurement window. The second part contains a comparison of eight estimation methods (ESPRIT, TLS, Prony LS, a newly developed IpDFT method and four other 3-point IpDFT methods) in respect of calculation time and accuracy for an ideal sine-wave signal, signal distorted by AWGN noise and a signal distorted by harmonics. The number of signal cycles is limited from 0.1 to 3 or 5. The results enable to select the most accurate/fastest estimation method in various measurement conditions. Parametric methods are more accurate but also much slower than IpDFT methods (up to 3000 times for the number of samples equal to 5000). The presented method is more accurate than other IpDFT methods and much faster than parametric methods, which makes it possible to use it as an alternative, especially in real-time applications.
    Źródło:
    Metrology and Measurement Systems; 2018, 25, 2; 283-302
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of Heart Rate Variability Fluctuations by Wavelet Transform
    Autorzy:
    Popov, A.
    Karplyuk, Y.
    Fesechko, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/226306.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    heart rate variability
    HRV fluctuations
    HRV wavelet analysis
    time-dependent HRV estimation
    wavelet transform
    Opis:
    Technique for separate estimation of fast and slow fluctuations in the heart rate signal is developed. The orthogonal dyadic wavelet transform is used to separate the slow heart rate changes in approximation part of decomposition and fast changes in detail parts. Experimental results using the recordings from persons practicing Chi meditation demonstrated the applicability of estimation heart rate fluctuations with the proposed approach.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 3; 395-400
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Regular design equations for the continuous reduced-order Kalman filter
    Autorzy:
    Hippe, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/229993.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    optimal estimation
    polynomials
    multivariable systems
    continuous-time systems
    Opis:
    Reduced-order Kalman filters yield an optimal state estimate for linear dynamical systems, where parts of the output are not corrupted by noise. The design of such filters can either be carried out in the time domain or in the frequency domain. Different from the full-order case where all measurements are noisy, the design equations of the reduced-order filter are not regular. This is due to the rank deficient measurement covariance matrix and it can cause problems when using standard software for the solution of the Riccati equations in the time domain. In the frequency domain the spectral factorization of the non-regular polynomial matrix equation does not cause problems. However, the known proof of optimality of the factorization result also requires a regular measurement covariance matrix. This paper presents regular (reduced-order) design equations for reduced-order Kalman filters in the time and in the frequency domains for linear continuous-time systems. They allow to use standard software for the design of the filter, to formulate the conditions for the stability of the filter and they also prove that the existing frequency domain solutions obtained by spectral factorization of a non-regular polynomial matrix equation are indeed optimal.
    Źródło:
    Archives of Control Sciences; 2011, 21, 4; 349-361
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Regular design equations for the discrete reduced-order Kalman filter
    Autorzy:
    Hippe, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/229814.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    optimal estimation
    polynomials
    multivariable systems
    discrete-time systems
    Opis:
    In the presence of white Gaussian noises at the input and the output of a system Kalman filters provide a minimum-variance state estimate. When part of the measurements can be regarded as noise-free, the order of the filter is reduced. The filter design can be carried out both in the time domain and in the frequency domain. In the case of full-order filters all measurements are corrupted by noise and therefore the design equations are regular. In the presence of noise-free measurements, however, they are not regular so that standard software cannot readily be applied in a time-domain design. In the frequency domain the spectral factorization of the non-regular polynomial matrix equation causes no problems. However, the known proof of optimality of the factorization result requires a regular measurement covariance matrix. This paper presents regular (reduced-order) design equations for the reduced-order discrete-time Kalman filter in the time and in the frequency domains so that standard software is applicable. They also allow to formulate the conditions for the stability of the filter and to prove the optimality of the existing solutions.
    Źródło:
    Archives of Control Sciences; 2012, 22, 2; 161-174
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Theoretical geodesy
    Autorzy:
    Borkowski, A.
    Kosek, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/145440.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    M-estimation
    robust estimation
    reliability
    time series
    polar motion
    niezawodność
    szeregi czasowe
    estymacja
    Opis:
    The paper presents a summary of research activities concerning theoretical geodesy performed in Poland in the period of 2011-2014. It contains the results of research on new methods of the parameter estimation, a study on robustness properties of the M-estimation, control network and deformation analysis, and geodetic time series analysis. The main achievements in the geodetic parameter estimation involve a new model of the M-estimation with probabilistic models of geodetic observations, a new Shift-Msplit estimation, which allows to estimate a vector of parameter differences and the Shift-Msplit(+) that is a generalisation of Shift-Msplit estimation if the design matrix A of a functional model has not a full column rank. The new algorithms of the coordinates conversion between the Cartesian and geodetic coordinates, both on the rotational and triaxial ellipsoid can be mentioned as a highlights of the research of the last four years. New parameter estimation models developed have been adopted and successfully applied to the control network and deformation analysis. New algorithms based on the wavelet, Fourier and Hilbert transforms were applied to find time-frequency characteristics of geodetic and geophysical time series as well as time-frequency relations between them. Statistical properties of these time series are also presented using different statistical tests as well as 2nd, 3rd and 4th moments about the mean. The new forecasts methods are presented which enable prediction of the considered time series in different frequency bands.
    Źródło:
    Geodesy and Cartography; 2015, 64, 2; 261-279
    2080-6736
    2300-2581
    Pojawia się w:
    Geodesy and Cartography
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation and correction of gain mismatch and timing error in time-interleaved ADCs based on DFT
    Autorzy:
    Guo, L.
    Tian, S.
    Wang, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/221135.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    correction
    estimation
    gain mismatch
    time-interleaved analog-to-digital converter
    timing error
    Opis:
    Time-interleaved analog-to-digital converter (ADC) architecture is crucial to increase the maximum sample rate. However, offset mismatch, gain mismatch, and timing error between time-interleaved channels degrade the performance of time-interleaved ADCs. This paper focuses on the gain mismatch and timing error. Techniques based on Discrete Fourier Transform (DFT) for estimating and correcting gain mismatch and timing error in an M-channel ADC are depicted. Numerical simulations are used to verify the proposed estimation and correction algorithm.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 3; 535-544
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    State estimation of networked control systems over limited capacity and dropout channels
    Autorzy:
    Liu, Qingquan
    Ding, Rui
    Chen, Chunqiang
    Powiązania:
    https://bibliotekanauki.pl/articles/229800.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    linear time-invariant systems
    limited capacity
    observability
    state estimation
    networked control
    data rate
    Opis:
    This paper investigates state estimation of linear time-invariant systems where the sensors and controllers are geographically separated and connected over limited capacity, additive white Gaussian noise (AWGN) communication channels. Such channels are viewed as dropout (erasure) channels. In particular, we consider the case with limited data rates, present a necessary and sufficient condition on the data rate for mean square observability over an AWGN channel. The system is mean square observable if the data rate of the channel is larger than the lower bound given. It is shown in our results that there exist the inherent tradeoffs among the limited data rate, dropout probability, and observability. An illustrative example is given to demonstrate the effectiveness of the proposed scheme.
    Źródło:
    Archives of Control Sciences; 2019, 29, 4; 687-697
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Observer-based fault estimation for linear systems with distributed time delay
    Autorzy:
    Filasova, A.
    Gontkovič, D.
    Krokavec, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/229173.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    adaptive fault estimation
    distributed time delay systems
    Lyapunov-Krasovskii functional
    integral partitioning technique
    time delay segmentation
    linear matrix inequalities
    Opis:
    The paper is engaged with the framework of designing adaptive fault estimation for linear continuous-time systems with distributed time delay. The Lyapunov-Krasovskii functional principle is enforced by imposing the integral partitioning method and a new equivalent delaydependent design condition for observer-based assessment of faults are established in terms of linear matrix inequalities. Asymptotic stability conditions are derived and regarded with respect to the incidence of structured matrix variables in the linear matrix inequality formulation. Simulation results illustrate the design approach, and demonstrates power and performance of the actuator fault assessment.
    Źródło:
    Archives of Control Sciences; 2013, 23, 2; 169-186
    1230-2384
    Pojawia się w:
    Archives of Control Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Geodesy: General theory and methodology 2015–2018
    Autorzy:
    Borkowski, Andrzej
    Kosek, Wiesław
    Ligas, Marcin
    Powiązania:
    https://bibliotekanauki.pl/articles/145489.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    niezawodność
    szereg czasowy
    szacowanie
    robust estimation
    reliability
    time series
    polar motion
    least squares collocation
    Opis:
    The summary of research activities concerning general theory and methodology performed in Poland in the period of 2015–2018 is presented as a national report for the 27th IUGG (International Union of Geodesy and Geophysics) General Assembly. It contains the results of research on new or improved methods and variants of robust parameter estimation and their application, especially to control network analysis. Reliability analysis of the observation system and an integrated adjustment approach are also given. The identifiability (ID) index as a new measure for minimal detectable bias (MDB) in the observation system of a network, has been introduced. A new method of covariance function parameter estimation in the least squares collocation has been developed. The robustified version of the Shift-Msplit estimation, termed as Shift-M*split estimation, which enables estimation of parameter differences (robustly), without the need of prior estimation of the parameters, has been introduced. Results on the analysis of geodetic time series, particularly Earth orientation parameter time series, geocenter time series, permanent station coordinates and sea level variation time series are also provided in this review paper. The entire bibliography of related works is provided in the references.
    Źródło:
    Geodesy and Cartography; 2019, 68, 1; 145-162
    2080-6736
    2300-2581
    Pojawia się w:
    Geodesy and Cartography
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Damped Zero-Pseudorandom Noise OFDM Systems
    Autorzy:
    Esmaiel, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/225983.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    time reversal
    TR
    channel estimation
    CE
    compressed sensing
    CS
    orthogonal frequency division multiplexing
    OFDM
    Opis:
    This paper proposed a new OFDM scheme called damped zero-pseudorandom noise orthogonal frequency division multiplexing (DZPN-OFDM) scheme. In the proposed scheme, ZPN-OFDM non-zero part is damped to reduce its energy, thus the mutual interference power in-between the data and training blocks with conservative the pseudo-noise conventional properties required for channel estimation or synchronization. The motivation of this paper is the OFDM long guard interval working in wide dispersion channels, whereas a significant energy is wasted when the conventional ZPN-OFDM is used as well as the BER performance is also degraded. Moreover, the proposed scheme doesn’t duplicate the guard interval to solve the ZPN-OFDM spectrum efficiency loss problem. Both detailed performance analysis and simulation results show that the proposed DZPNOFDM scheme can, indeed, offer significant bit error rate, spectrum efficiency and energy efficiency improvement.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 4; 433-438
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of task completion times with the use of the PERT method on the example of a real construction project
    Szacowanie czasów realizacji zadań z wykorzystaniem metody PERT na przykładzie konkretnej realizacji
    Autorzy:
    Plebankiewicz, E.
    Juszczyk, M.
    Malara, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/230964.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    przedsięwzięcie budowlane
    metoda PERT
    zadanie
    czas realizacji
    szacowanie
    construction project
    PERT method
    task
    completion time
    estimation
    Opis:
    The article presents briefly several methods of working time estimation. However, three methods of task duration assessment have been selected to investigate working time in a real construction project using the data collected from observing workers laying terrazzo flooring in staircases. The first estimation has been done by calculating a normal and a triangular function. The next method, which is the focus of greatest attention here, is PERT. The article presents a way to standardize the results and the procedure algorithm allowing determination of the characteristic values for the method. Times to perform every singular component sub-task as well as the whole task have been defined for the collected data with the reliability level of 85%. The completion time of the same works has also been calculated with the use of the KNR. The obtained result is much higher than the actual time needed for execution of the task calculated with the use of the previous method. The authors argue that PERT is the best method of all three, because it takes into account the randomness of the entire task duration and it can be based on the actual execution time known from research.
    W artykule przedstawiono kilka metod szacowania czasu pracy: metoda delficka, COCOMO II, Use Case Points, PERT, Katalogi Nakładów Rzeczowych i matematyczne funkcje rozkładu prawdopodobieństwa. We wstępie teoretycznym po krótce omówiono podstawy każdej z nich. Metoda delficka jest metodą heurystyczną, opartą na doświadczeniach ekspertów. Przewidywana prognoza prawdopodobieństwa realizacji zadania określona zostaje na podstawie serii ankiet. COCOMO II jest modelem służącym do oszacowania nakładu pracy. Wyniki zostały opracowane na podstawie analizy ponad 60 projektów. Metoda Use Case Points pochodzi z metody punktów funkcyjnych. Przy wykorzystywaniu tej metody bierze się pod uwagę czynniki środowiskowe, czynniki złożoności technicznej projektów, osoby realizujące projekt w zestawieniu z rzeczywistymi pomiarami. Wśród metod sieciowych opisanym przypadkiem jest PERT (Program Evaluation and Review Technique). Należy ona do grupy deterministycznych, opartych na znalezieniu ścieżki krytycznej (podobnie jak wCPM), a następnie ustaleniu parametrów rozkładu prawdopodobieństwa: optymistycznego czasu zakończenia zadania (a), najbardziej prawdopodobnego czasu zakończenia zadania (m) i pesymistycznego czasu zakończenia zadania (b). Z uwagi na jej charakter można z łatwością stosować metody statystyczne do oceny ryzyka dotrzymania terminu realizacji zadań. Ostatnią omówioną metodą szacowania czasów realizacji są Katalogi Nakładów Rzeczowych.
    Źródło:
    Archives of Civil Engineering; 2015, 61, 3; 51-62
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Comparison of Various Overhead Arrangements for Massive MIMO-OFDM Channel Estimation
    Autorzy:
    Sure, P.
    Bhuma, C. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/226978.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Massive MIMO-OFDM
    time domain synchronous
    comb type with cyclic prefix
    grid type with cyclic prefix
    denoising threshold
    LS channel estimation
    Opis:
    Massive multi input multi output (MIMO) systems incorporate orthogonal frequency division multiplexing (OFDM) technology to render high data rate services for future wireless communication applications. The channel estimator (CE) employed by a reliable massive MIMO-OFDM system requires huge amount of overhead in the form of known and null data transmissions, hence limiting the system spectral efficiency (SE). Often, CE design is a tradeoff between SE and system reliability. In this paper, CE with three different overhead arrangements, namely time domain synchronous (TDS), comb type with cyclic prefix (CTCP), 2D grid type with cyclic prefix (GTCP) are investigated and a GTCP based CE is proposed which offers both high SE and improved system reliability. The proposed CE uses autocorrelation based denoising threshold for channel impulse response (CIR) estimation and does not require any knowledge of channel statistics (KCS). A416 MIMO-OFDM system is simulated in a rayleigh fading channel environment with U-shaped doppler spectrum. From the bit error rate (BER) performance results in WiMax SUI-4, Advanced Television Technology Center (ATTC) and Brazil A channel environments, it is verified that the proposed CE with GTCP overhead and proposed denoising scheme, indeed improves both SE and system reliability. Hence it is suitable for application in all massive MIMO-OFDM systems.
    Źródło:
    International Journal of Electronics and Telecommunications; 2014, 60, 2; 173-179
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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