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 "Borkowski, J." wg kryterium: Autor

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-13 z 13
    Tytuł:
    Systematic errors of the LIDFT method: analytical form and verification by a Monte Carlo method
    Autorzy:
    Borkowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/221176.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    LIDFT
    multifrequency signal
    interpolated DFT
    spectrum estimation
    zero padding
    unit circle
    approximation by polygon
    Opis:
    This paper derives analytical formulas for the systematic errors of the linear interpolated DFT (LIDFT) method when used to estimating multifrequency signal parameters and verifies this analysis using Monte-Carlo simulations. The analysis is performed on the version of the LIDFT method based on optimal approximation of the unit circle by a polygon using a pair of windows. The analytical formulas derived here take the systematic errors in the estimation of amplitude and frequency of component oscillations in the multifrequency signal as the sum of basic errors and the errors caused by each of the component oscillations. Additional formulas are also included to analyze particular quantities such as a signal consisting of two complex oscillations, and the analyses are verified using Monte-Carlo simulations.
    Źródło:
    Metrology and Measurement Systems; 2012, 19, 4; 673-684
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Continuous and discontinuous linear approximation of the window spectrum by least squares method
    Autorzy:
    Borkowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/221777.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    data window
    spectrum approximation
    interpolated DFT
    LIDFT
    spectrum estimation
    zero padding
    Opis:
    This paper presents the general solution of the least-squares approximation of the frequency characteristic of the data window by linear functions combined with zero padding technique. The approximation characteristic can be discontinuous or continuous, what depends on the value of one approximation parameter. The approximation solution has an analytical form and therefore the results have universal character. The paper presents derived formulas, analysis of approximation accuracy, the exemplary characteristics and conclusions, which confirm high accuracy of the approximation. The presented solution is applicable to estimating methods, like the LIDFT method, visualizations, etc.
    Źródło:
    Metrology and Measurement Systems; 2011, 18, 3; 379-390
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Minimization of maximum errors in universal approximation of the unit circle by a polygon
    Autorzy:
    Borkowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/221779.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    unit circle
    approximation by polygon
    LIDFT
    interpolated DFT
    zero padding
    Opis:
    This paper presents a universal approximation of the unit circle by a polygon that can be used in signal processing algorithms. Optimal choice of the values of three parameters of this approximation allows one to obtain a high accuracy of approximation. The approximation described in the paper has a universal character and can be used in many signal processing algorithms, such as DFT, that use the mathematical form of the unit circle. One of the applications of the described approximation is the DFT linear interpolation method (LIDFT). Applying the results of the presented paper to improve the LIDFT method allows one to significantly decrease the errors in estimating the amplitudes and frequencies of multifrequency signal components. The paper presents the derived formulas, an analysis of the approximation accuracy and the region of best values for the approximation parameters.
    Źródło:
    Metrology and Measurement Systems; 2011, 18, 3; 391-402
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Interpolated-DFT-Based Fast and Accurate Amplitude and Phase Estimation for the Control of Power
    Autorzy:
    Borkowski, J.
    Kania, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/221570.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    control of power
    grid signal
    amplitude and phase estimation
    renewable energy
    interpolated DFT
    maximum decay side-lobes windows
    Opis:
    Quality of energy produced in renewable energy systems has to be at the high level specified by respective standards and directives. One of the most important factors affecting quality is the estimation accuracy of grid signal parameters. This paper presents a method of a very fast and accurate amplitude and phase grid signal estimation using the Fast Fourier Transform procedure and maximum decay side-lobes windows. The most important features of the method are elimination of the impact associated with the conjugate’s component on the results and its straightforward implementation. Moreover, the measurement time is very short ‒ even far less than one period of the grid signal. The influence of harmonics on the results is reduced by using a bandpass pre-filter. Even using a 40 dB FIR pre-filter for the grid signal with THD ≈ 38%, SNR ≈ 53 dB and a 20‒30% slow decay exponential drift the maximum estimation errors in a real-time DSP system for 512 samples are approximately 1% for the amplitude and approximately 8.5・10‒2 rad for the phase, respectively. The errors are smaller by several orders of magnitude with using more accurate pre-filters.
    Źródło:
    Metrology and Measurement Systems; 2016, 23, 1; 13-26
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of A/D quantization in an interpolated DFT based system of power control with a small delay
    Autorzy:
    Borkowski, J.
    Kania, D.
    Mroczka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/221386.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    photovoltaic system
    frequency estimation
    signal processing
    A/D converter
    control of power system
    Opis:
    Fast and accurate grid signal frequency estimation is a very important issue in the control of renewable energy systems. Important factors that influence the estimation accuracy include the A/D converter parameters in the inverter control system. This paper presents the influence of the number of A/D converter bits b, the phase shift of the grid signal relative to the time window, the width of the time window relative to the grid signal period (expressed as a cycle in range (CiR) parameter) and the number of N samples obtained in this window with the A/D converter on the developed estimation method results. An increase in the number b by 8 decreases the estimation error by approximately 256 times. The largest estimation error occurs when the signal module maximum is in the time window center (for small values of CiR) or when the signal value is zero in the time window center (for large values of CiR). In practical applications, the dominant component of the frequency estimation error is the error caused by the quantization noise, and its range is from approximately 8×10-10 to 6×10-4.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 3; 423-432
    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:
    Theoretical and experimental research of anti-tank kinetic penetrator ballistics
    Autorzy:
    Motyl, K.
    Magier, M.
    Borkowski, J.
    Zygmunt, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/200983.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hypersonic projectile
    mathematical model
    simulation of flight
    pocisk militarny
    model matematyczny
    Symulacja lotu
    Opis:
    A mathematical-physical model of the hypersonic anti-tank kinetic subcalibre projectile for 120 mm munition was built. Computer simulations of the projectile flight were performed for any angle of shooting, from 0° to 90°. Trajectories of projectile flights were determined considering all angles of shooting. Theoretical calculations were verified by experimental measurement of the projectile velocity in time while shooting on a test range. Some conclusions with regard to safety during hypersonic projectile shooting on the test range were formulated.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 3; 399-404
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of Salmonella enteritidis recombinant heat shock protein 60 production
    Autorzy:
    Rainczak, K.
    Bajzert, J.
    Galli, J.
    Selera, A.
    Wieliczko, A.
    Borkowski, J.
    Stefaniak, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/31046.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    HSP60 protein
    Salmonella enteritidis
    heat shock protein
    host
    Escherichia coli
    Opis:
    The aim of the study was to optimize conditions for producing Salmonella Enteritidis recombinant heat shock protein 60 (rHsp60). Seven Escherichia coli host strains (Rosetta, Turner, C41, C43, Origami, BL21pLys, Rosetta pLys) were transformed by a recombinant plasmid containing Hsp60 gene from Salmonella Enteritidis, and then cultured and induced by isopropyl-β-D-thiogalactopyranoside (IPTG). The highest S. Enteritidis rHsp60 yield was obtained using E. coli strain C41. Induction of this strain using IPTG allowed the yield 400 μg of S. Enteritidis Hsp60 protein/2L of culture, but by autoinduction the yield exceeded 800 μg/2L.
    Źródło:
    Polish Journal of Veterinary Sciences; 2011, 14, 1
    1505-1773
    Pojawia się w:
    Polish Journal of Veterinary Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Description of matrix converter in frequency domain
    Autorzy:
    Borkowski, D.
    Sobczyk, T. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/140584.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    harmonic balance method
    atrix converter
    requency domain
    Opis:
    The paper presents abilities and advantages following from the use of the harmonicbalance method for analysis of steady state of a multiphase system with switching devices on example of a matrix converter. Switching elements are modelled as resistances with step-wise variable parameters, what allows to describe the converter by a linear infinite set of equations. The analysis in frequency domain is presented on example of the one-periodic control strategy. External systems were also added using the Thevenin method approach. The numerical calculation results of a linear equations set were verified by the variable structure method in a time domain and the numerical convergence was confirmed. Furthermore, the exemplary complex system was analysed using the cascade method and current waveforms were obtained.
    Źródło:
    Archives of Electrical Engineering; 2013, 62, 3; 387-400
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of commutation conditions on steady states in matrix converter
    Autorzy:
    Borkowski, D.
    Sobczyk, T. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/141341.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    przekształtnik macierzowy
    regulacja przepływu mocy
    metoda bilansu harmonicznych
    matrix converter
    power flow control
    harmonic balance method
    Opis:
    The paper investigates a significant influence of transients on steady states in a matrix converter with the one-periodic control strategy. Proposed controller can be used as an interconnection device within a power system for a power flow control. However, the presence of inductances in external systems has the significant influence on steady state of a matrix converter operation. The special current injection method has been developed to ensure a proper operation of a matrix converter. Presented analysis of steady states is carried out in a frequency domain using the harmonic balance method. Obtained numerical results, which are confirmed by a time domain analysis, prove the effectiveness of the proposed method.
    Źródło:
    Archives of Electrical Engineering; 2011, 60, 1; 77-83
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sulphate and arsenate minerals as environmental indicators in the weathering zones of selected ore deposits, Western Sudetes, Poland
    Autorzy:
    Parafiniuk, J.
    Siuda, R.
    Borkowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/139438.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    sulphates
    arsenates
    Slavikite
    zýkaite
    kaňkite
    pitticite
    fosforany
    arseniany
    zýkait
    kaňkit
    pitticit
    Opis:
    The results of a complex investigation of the sulphate and arsenate assemblages forming in the weathering zone of selected ore deposits in the Sudetes are presented. The development of the weathering zone has been characterised in the polymetallic ore deposits at Miedzianka–Ciechanowice and Radzimowice, and the pyrite deposit at Wieściszowice, which differ in the chemical compositions of the ore and barren minerals and the hydrological conditions. Secondary sulphate and arsenate mineral assemblages vary significantly among the ore deposits under study. Their crystallization is discussed, taking into consideration the stability of particular minerals and the paths of their transformation. It is shown that these minerals have great potential as indicators of weathering processes. A significant role for microorganisms in the formation of the weathering zone of the ore deposits under study is also proven.
    Źródło:
    Acta Geologica Polonica; 2016, 66, 3; 493-508
    0001-5709
    Pojawia się w:
    Acta Geologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fe analysis of a steam turbine HP rotor blade stage concerning material effort, dynamic properties and creep damage assessment
    Analiza MES wysokoprężnego stopnia turbiny parowej dotycząca wytężenia materiału, własności dynamicznych i oceny trwałości ze względu na pełzanie
    Autorzy:
    Borkowski, P.
    Głowacki, D.
    Nowakowska, A.
    Pawlicki, J.
    Zwoliński, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/139804.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    steam turbine
    structural analysis
    creep analysis
    modal analysis
    finite element method
    FEM
    turbina parowa
    analiza strukturalna
    analiza pełzania
    analiza modalna
    metoda elementów skończonych
    MES
    Opis:
    This paper is concerned with the 1st stage of HP rotor blade assembly steam turbine TK 120. The methodology was focused on the selection of mechanical properties and the way of the rotor disc modeling and estimating the degree of damage caused by creep. Then the dynamic interference between the frequencies of excitation and the natural frequencies was assessed. Static calculations were performed for the cyclic sectors consisting of the disc, disc blades, spacers and shrouding, including loads as temperature, mass forces from the angular velocity and the pressure on the blades. Then, the creep analysis using a Norton’s model and the modal analysis were performed. Static analysis gave information concerning the distributions of displacements, stress and strain components. In the creep analysis, the creep displacements and stress relaxation versus time were determined and the estimated degree of damage caused by creep was evaluated at each part of the rotor disc. In the modal analysis, the natural frequencies and modes of vibrations corresponding to the nodal diameters were found. The results of modal analysis were shown in the SAFE graph. Numerical calculations have shown that the rotor disc was a well-designed structure and did not reveal any dynamic interference.
    Praca dotyczyła pierwszego stopnia wysokoprężnej części wirnika turbiny parowej TK 120. Przedstawiono metodykę doboru właściwości mechanicznych, sposobu modelowania wirnika, szacowania stopnia zużycia spowodowanego pełzaniem oraz oceny interferencji dynamicznych pomiędzy częstościami wymuszeń a częstościami drgań własnych. W obliczeniach statycznych modelu tarczy wirnika z łopatkami, przekładkami i bandażem wykorzystano cykliczną symetrię, z uwzględnieniem temperatury, sił masowych od wirowania i ciśnienia na łopatkach. Następnie przeprowadzono analizę pełzania według modelu Nortona oraz analizę modalną. W obliczeniach statycznych wyznaczono rozkłady przemieszczeń, odkształceń i naprężeń. W analizie pełzania wyznaczono przemieszczenia pełzania i relaksację naprężeń w czasie oraz oszacowano stopień zużycia ze wzgledu na pełzanie w poszczególnych częściach wirnika turbiny. W analizie dynamicznej wyznaczono częstości i postacie drgań własnych odpowiadajace poszczególnym średnicom węzłowym. Wyniki analizy modalnej przedstawiono na wykresie SAFE. Obliczenia numeryczne wykazały, że wirnik jest konstrukcją dobrze zaprojektowaną i nie wykazującą interferencji dynamicznych.
    Źródło:
    Archive of Mechanical Engineering; 2016, LXIII, 1; 163-185
    0004-0738
    Pojawia się w:
    Archive of Mechanical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nanocrystalline Ag-Re Composite as a Potential Material for Electric Contacts Fabrication
    Autorzy:
    Kołacz, D.
    Księżarek, S.
    Woch, M.
    Karwan-Baczewska, J.
    Staszewski, M.
    Rudnicki, K.
    Borkowski, P.
    Sienicki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/354356.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    electric contact
    composite
    nanocrystalline
    contact materials
    arc erosion
    examination methods
    electric properties
    Opis:
    A new silver-based composite material with an addition of 1 and 10 mass % of rhenium, for prospective application in the production of electric contacts, has been presented. The paper shows results of the research and experimental works aimed at developing technology for fabrication of semiproducts (wires and bimetallic contacts) by classical powder metallurgy methods and by a method enabling production of nanocrystalline composite. At each stage of the processes involved, physical, mechanical and technological properties of the materials were investigated. Particular attention was given to final products and semiproducts prepared in a form of bimetallic contacts. It was found that the composite with nanocrystalline structure may be a good material for ecological electric contacts.
    Źródło:
    Archives of Metallurgy and Materials; 2016, 61, 4; 1847-1852
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

      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