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    Tytuł:
    The North Sea Bicycle Race ECG project : time-domain analysis
    Autorzy:
    Długosz, D.
    Eftestøl, T.
    Królak, A.
    Wiktorski, T.
    Ørn, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/384850.pdf
    Data publikacji:
    2018
    Wydawca:
    Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
    Tematy:
    ECG
    principal Component Analysis
    silhouette analysis
    clustering
    EKG
    analiza głównych składowych
    grupowanie
    klastering
    Opis:
    Analysis of electrocardiogram and heart rate provides useful information about health condition of a patient. The North Sea Bicycle Race is an annual cycling competition in Norway. Examination of ECG recordings collected from participants of this race may allow defining and evaluating the relationship between physical endurance exercises and heart electrophysiology. Parameters reflecting potentially alarming deviations are to be identified in this study. This paper presents results of a time-domain analysis of ECG data collected in 2014, implementing K-Means clustering. A double stage analysis strategy, aimed at producing hierarchical clusters, is proposed. The first phase allows rough separation of data. Second stage is applied to reveal internal structure of the majority clusters. In both steps, discrepancies driving the separation could stem from three sources. Firstly, they could be signs of abnormalities in electrical activity of the heart. Secondly, they may allow discriminating between natural groups of participants – according to sex, age, physical fitness. Finally, some deviations could result from faults in data extraction, therefore serving in evaluation of the parameters. The clusters were defined predominantly by combinations of features: heartbeat signals correlation, P-wave shape, and RR intervals; none of the features alone was discriminative for all the clusters.
    Źródło:
    Journal of Automation Mobile Robotics and Intelligent Systems; 2018, 12, 1; 23-32
    1897-8649
    2080-2145
    Pojawia się w:
    Journal of Automation Mobile Robotics and Intelligent Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The time domain analysis of interactions in the wheel - rail contacts due to discontinuous time periodic loads
    Autorzy:
    Trzaska, M.
    Trzaska, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/246731.pdf
    Data publikacji:
    2012
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    railway transport
    wheel-rail contact
    discontinuous time periodic forces
    energy absorbed by rail
    strength susceptibility
    Opis:
    In this paper, we present Fourier series less approaches for determining the energy produced by discontinuous time periodic forces in the wheel-rail contacts of the railway track systems. The vehicle system model used in this study consists of a quarter car supported on a bogie, while the side frame is supported on two wheel sets. The main advantage of the presented method is the total elimination of frequency analysis, which in effect introduces important simplifications in the identification of the energetic effects in the contact. Fundamental properties of contact displacements of the rail surface have been considered on the basis of the newly established method. The contact zone between railway wheels and the rail surfaces made of bulk materials is perceived as strong enough to resist the normal (vertical) forces introduced by heavy loads and the dynamic response induced by track and wheel irregularities. The analysis is carried out for a wheel running on an elastic rail rested on sleepers arranged on completely rigid foundation. The established model of the wheel-rail contact dynamics has been applied to that same roll plane, but with taking into account a nonlinear characteristic of the sleeper with respect to the ground. Attention then is focused completely on the modelling of the energy absorbed by the rail. The applied method employs the energy state variables as time functions leading to determine the susceptibility of a given contact on the strength induced by the rail roll.
    Źródło:
    Journal of KONES; 2012, 19, 2; 531-542
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation on the applicability of the time domain analysis of discharges in gases for the defect identification at AC voltage
    Autorzy:
    Lühring, U.
    Wienold, D.
    Jenau, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/136164.pdf
    Data publikacji:
    2017
    Wydawca:
    EEEIC International Barbara Leonowicz Szabłowska
    Tematy:
    AC voltage
    contact noise
    corona discharge
    pulse shape
    surface discharge
    time domain analysis
    Opis:
    The partial discharge diagnosis is an established instrument for the condition assessment of high voltage insulations and equipment. Under AC voltage stress the phase resolved pattern is of great significance in order to become aware of the type of fault. As a result of the inapplicability for DC voltage stress, approaches for alternative interpretation techniques such as the time domain analysis of partial discharges were identified in recent investigations. In these different types of fault are taken into account as well as different insulating media. The purpose of this paper is to investigate whether an analysis of the pulse shape is also applicable for the defect identification under AC voltage stress. By focussing on gaseous insulating media, contact noise and surface discharges are emulated in ambient air, whereas corona discharges are emulated in ambient air and oxygen. A method for analysing discharges, occurring in the negative and the positive half-wave of the test voltage, is proposed and discussed.
    Źródło:
    Transactions on Environment and Electrical Engineering; 2017, 2, 1; 34-41
    2450-5730
    Pojawia się w:
    Transactions on Environment and Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time and frequency domain analysis of partial discharges using electrical method
    Autorzy:
    Kunicki, M.
    Cichoń, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/973070.pdf
    Data publikacji:
    2016
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    partial discharges
    electrical method
    IEC 60270
    frequency domain
    time domain
    Opis:
    Partial discharge (PD) measurement results with particular consideration of time domain and frequency domain analysis of pulses generated by PD model sources are presented in the paper. Three different PD generation model sources are selected for the research: surface type, point to point and multi-point to plate. All measurements are proceeded under laboratory conditions using electrical method of a PD detection, according to the IEC60270 standard. Various amplitude and power density spectrum descriptors are proposed, as well as PD source type identification abilities on grounds of the selected descriptors are considerated. Electrical power transformers on-line PD detection and evaluation systems improvement and development are the main purpose of the presented research. Laboratory experiment results gives a solid base for further research focused on verification of the proposed methodology on a real life apparatus.
    Źródło:
    Measurement Automation Monitoring; 2016, 62, 2; 72-77
    2450-2855
    Pojawia się w:
    Measurement Automation Monitoring
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ nurkowania na stan autonomicznego układu nerwowego paraplegików określony za pomocą analizy czasowej zmienności rytmu zatokowego serca. Doniesienie wstępne
    The diving influence on the autonomic nervous system of the paraplegics measured by the heart rate variability time domain analysis. Preliminary results
    Autorzy:
    Graczyk, D.
    Jethon, Z.
    Magiera, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/366437.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Medycyny i Techniki Hiperbarycznej
    Tematy:
    nurkowanie
    zmienność rytmu zatokowego
    paraplegia
    nurkowanie osób niepełnosprawnych
    diving
    heart rate variability
    disabled divers
    Opis:
    Nurkowanie staje się coraz powszechniej dostępne, również dla niepełnosprawnych. Za pomocą analizy zmienności rytmu zatokowego serca można określić jak nurkowanie wpływa na autonomiczny układ nerwowy. Przebadano 19 mężczyzn z paraplegią podczas nurkowania rekreacyjnego i z zadaniami. Oba rodzaje nurkowania powodują wzrost aktywności cześci współczulnej, inaczej niż u pełnosprawnych. Nie jest to korzystna zmiana dla osób z uszkodzeniem rdzenia kregowego.
    The diving is becoming very popular, also for disabled persons. Heart Rate Variability can define how diving influence on autonomic nervous system. 19 men with paraplegia has been examined during 2 dives: recreational and task. Both kinds of dives induce sympathetic nervous system hyperactivity, otherwise than among healthy divers. It's not good for divers with spinal cord injury
    Źródło:
    Polish Hyperbaric Research; 2008, 3(24); 35-43
    1734-7009
    2084-0535
    Pojawia się w:
    Polish Hyperbaric Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    High-efficiency carrier frequency estimation algorithm for real-time multi-domain communication signal analysis
    Autorzy:
    Wang, Q.
    Yang, X.
    Yan, X
    Qin, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/221239.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    carrier frequency estimation
    multi-domain communication
    signal analysis
    Opis:
    Based on real-time multi-domain communication signal analysis architecture, a high-efficiency blind carrier frequency estimation algorithm using the power spectrum symmetry of the measured modulated signal is presented. The proposed algorithm, which utilizes the moving averaged power spectrum achieved by the realtime spectrum analysis, iteratively identifies the carrier frequency in according to the power difference between the upper sideband and lower sideband, which is defined and revised by the estimated carrier frequency in each iteration. When the power difference of the two sidebands converges to the preset threshold, the carrier frequency can be obtained. For the modulation analysis, the measured signal can be coarsely compensated by the estimated result, and the residual carrier frequency error is eliminated by a following carrier synchronization loop. Compared with previous works, owing to the moving averaged power spectrum normalization and the smart iterative step variation mechanism for the two sidebands definition, the carrier frequency estimation accuracy and speed can be significantly improved without increasing the computational effort. Experimental results are included to demonstrate the outstanding performance of the proposed algorithm.
    Źródło:
    Metrology and Measurement Systems; 2014, 21, 2; 281-292
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zaawansowane metody analiz w pomiarach jakości energii elektrycznej
    Advanced signal analysis methods in power quality measurements
    Autorzy:
    Górecki, K.
    Szmajda, M.
    Zygarlicki, J.
    Zygarlicka, M.
    Mroczka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/157311.pdf
    Data publikacji:
    2011
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    jakość energii elektrycznej
    częstotliwościowe analizy sygnałów
    czasowo-częstotliwościowe analizy sygnałów
    power quality
    frequency domain signal analysis
    time-frequency domain signal analysis
    Opis:
    W artykule przedstawiono problematykę pomiarów jakości energii elektrycznej oraz zaprezentowano najważniejsze metody analizy zakłóceń występujących w sieciach elektroenergetycznych, jakie rozwijane są w zespole zajmującym się jakością energii elektrycznej w Instytucie Automatyki i Informatyki Politechniki Opolskiej. Przedstawiono systematykę metod analiz sygnałów oraz określono metody wykorzystywane obecnie w pomiarach sygnałów elektrycznych. Ponadto zaprezentowano metody alternatywne do transformacji Fouriera umożliwiające precyzyjną analizę częstotliwościową (analiza Prony'ego) oraz lokalizację zakłóceń za pomocą metod czasowo-częstotliwościowych (transformacja Falkowa, dyskretna transformacja Falkowa, dystrybucja Wignera-Ville'a i jej odmiany, transformacja Gabora-Wignera).
    The issue of measuring power quality parameters and the most important analyses of disturbances occurring in the power network are presented in the paper. These subjects are developed by a power quality and signal analysis group, working at the Faculty of Electrical Engineering, Automatic Control and Informatics. The basic classification of signal analysis methods is given in the paper (Fig. 1). Moreover, the methods currently used in power quality measurement systems are described. In most cases the analyses are based on Fourier Transformation [2-4]. The methods, due to 10-cycles measurement period, cause significant computational errors in case of existence of short duration harmonics in a signal. Moreover, very precise synchronization of the sampling frequency and real power wave-form frequency is needed. Therefore other kinds of analyses in power quality measurement systems are currently investigated. The alternative to Fourier Transformation methods allowing precise estimation of the signal spectrum is Prony analysis [5]. The analysis enables extracting frequency components on the basis of a much shorter measurement window than FFT [6-10]. For localizing the power disturbances, linear (Short-Time Fourier analysis STFT, Gabor Transform GT [12, 13], Wavelet Transform [14, 15, 16]) and bilinear (Wigner-Ville WVD, Pseudo-WVD [17,18]) time-frequency analyses are performed. The combination of both groups of methods (Gabor-Wigner Transform GWT [19,20]) is also presented in the paper. Application of image processing algorithms [21, 22] is also considered in the paper.
    Źródło:
    Pomiary Automatyka Kontrola; 2011, R. 57, nr 3, 3; 284-286
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Diagnostyka rdzenia transformatora elektroenergetycznego z wykorzystaniem zmodyfikowanej metody wibroakustycznej
    Diagnosis of power transformer core using the modified vibroacoustic method
    Autorzy:
    Borucki, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/153865.pdf
    Data publikacji:
    2011
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    transformator elektroenergetyczny
    rdzeń
    diagnostyka
    analiza czasowo-częstotliwościowa
    drgania
    metoda wibroakustyczna
    power transformer
    core
    diagnosis
    time and frequency domain analysis
    vibration
    vibroacoustic method
    Opis:
    Genezę podjętych w artykule prac stanowi problem skutecznej oceny stanu technicznego konstrukcji mechanicznej rdzeni transformatorów elektroenergetycznych. W publikacji zaprezentowano wyniki wskazujące na możliwość opracowania nowej i bezinwazyjnej metody diagnostycznej rdzeni z wykorzystaniem zaproponowanej przez autora tzw. zmodyfikowanej metody wibroakustycznej (MVM). Zamieszczone w artykule oryginalne rezultaty badań uzyskano podczas prób laboratoryjnych z wykorzystaniem transformatora olejowego o mocy 200 kVA.
    The problem of effective assessment of the technical condition of power transformer core mechanical structure originated the research work discussed in this paper. The investigation results show the possibility of developing a new and non-invasive diagnostic method for the transformer magnetic circuit. The method developed is based on time-frequency analysis of measured mechanical vibrations of the device monitored. The recording of vibrations is performed during the monitored transformer no-load operation. The paper characterises the power object under study (Fig. 1), the measuring system applied and discusses the new methodology for assessing the core technical condition using the modified vibroacoustic method (MVM). The original measurement results presented in the paper were obtained during switching on a 200 kVA transformer under laboratory conditions. The analysis of the signals measured was carried out for three operating conditions of the transformer under study: with the core pressed by a manufacturer; with the core with loose screws fixing the upper yoke (Fig. 2a) and with the core with loose screws fixing the upper and lower yokes (Fig. 2b). The research results (Figs. 3-5) obtained from this experiment show a potential possibility of developing a non-destructive and effective method for assessing the technical condition of the core mechanical structure of transformer units operating in the electric power system, especially the ones of a strategic character.
    Źródło:
    Pomiary Automatyka Kontrola; 2011, R. 57, nr 4, 4; 331-334
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improved algorithm for periodic steady-state analysis in nonlinear electromagnetic devices
    Autorzy:
    Sobczyk, T. J.
    Radzik, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/201260.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    electromagnetic devices
    steady-state analysis
    periodic solutions
    analysis in time domain
    discrete differential operator
    iterative algorithms
    Opis:
    This paper presents the improved methodology for the direct calculation of steady-state periodic solutions for electromagnetic devices, as described by nonlinear differential equations, in the time domain. A novel differential operator is developed for periodic functions and the iterative algorithm determining periodic steady-state solutions in a selected set of time instants is identified. Its application to steady-state analysis is verified by an elementary example. The modified algorithm reduces the complexity of steady-state analysis, particularly for electromagnetic devices described by high-dimensional nonlinear differential equations.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 5; 863-869
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Algorithm for determining two-periodic steady-states in AC machines directly in time domain
    Autorzy:
    Sobczyk, T.J.
    Powiązania:
    https://bibliotekanauki.pl/articles/141171.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    AC machines
    steady state analysis
    two-periodic solutions
    analysis in time domain
    discrete differential operator
    iterative algorithms
    Opis:
    This paper describes an algorithm for finding steady states in AC machines for the cases of their two-periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain despite of the fact that two-periodic waveforms are not repeated in any finite time interval. The basis for such an algorithm is a discrete differential operator that specifies the temporary values of the derivative of the twoperiodic function in the selected set of points on the basis of the values of that function in the same set of points. It allows to develop algebraic equations defining the steady state solution reached in a chosen point set for the nonlinear differential equations describing the AC machines when electrical and mechanical equations should be solved together. That set of those values allows determining the steady state solution at any time instant up to infinity. The algorithm described in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.
    Źródło:
    Archives of Electrical Engineering; 2016, 65, 3; 575-583
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Algorytm określania stanów ustalonych w maszynach prądu przemiennego bezpośrednio w dziedzinie czasu
    Algorithm determining steady-states for ac machines directly in time domain
    Autorzy:
    Sobczyk, T. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1367658.pdf
    Data publikacji:
    2015
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Napędów i Maszyn Elektrycznych Komel
    Tematy:
    maszyny prądu przemiennego
    analiza stanów ustalonych
    rozwiązania prawie-okresowe
    analiza w dziedzinie czasu
    dyskretny operator różniczkowania
    periodic steady-state solution
    analysis in time domain
    discrete differentiating operator
    Opis:
    The main aim of consideration is to find relations for direct determination in time domain of periodic steady-state solutions for differential equations. Consideration starts from a case of a set of linear periodic differential equations having periodic steady-state solution, for which that solution can be find in frequency domain by harmonic balance method. Required equations have been find using relations between Fourier coefficients and values of periodic function in time, which has been done in the matrix form. A new discrete operator of differentiating has been defined. As a result a set of algebraic equations has been written. Base on it an algorithm for nonlinear differential equations has been proposed. Numerical tests have been done both for a new discrete operator and for steady-state analysis in a simply electromechanical converter.
    W pracy opisano algorytm wyznaczania stanów ustalonych w maszynach elektrycznych prądu przemiennego dla przypadków ich dwu-okresowego charakteru. Algorytm umożliwia określenie rozwiązań ustalonych bezpośrednio w dziedzinie czasu pomimo, że przebiegi dwu-okresowe są niepowtarzalne w żadnym skończonym przedziale czasu. Bazą dla rozważań jest dyskretny operator różniczkowania określający chwilowe wartości pochodnej funkcji dwu-okresowej w wybranym zbiorze punktów na podstawie wartości funkcji w tym zbiorze. Umożliwia on zapisanie równań algebraicznych określających wartości rozwiązania ustalonego w tym zbiorze punktów, a na ich podstawie określenie wartości rozwiązania ustalonego w dowolnej chwili nieskończonego przedziału czasu. Algorytm opisany w pracy jest konkurencyjny w stosunku do znanych w literaturze równań wyznaczających takie stany ustalone w dziedzinie częstotliwości metodą bilansu harmonicznych.
    Źródło:
    Maszyny Elektryczne: zeszyty problemowe; 2015, 3, 107; 1-5
    0239-3646
    2084-5618
    Pojawia się w:
    Maszyny Elektryczne: zeszyty problemowe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of novel discrete differential operator of periodic function to study electromechanical interactions
    Autorzy:
    Sobczyk, T. J.
    Radzik, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/201412.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    electromechanical system
    steady state analysis
    periodic solutions
    analysis in time domain
    discrete differential operator
    iterative algorithms
    system elektromechaniczny
    analiza stanu ustalonego
    rozwiązania okresowe
    analiza w dziedzinie czasu
    dyskretny operator różniczkowania
    algorytm iteracyjny
    Opis:
    This paper investigates an algorithm for finding steady-states in electromechanical systems for the cases of their periodic nature. The algorithm enables to specify the steady-state solution identified directly in time domain. The basis for such an algorithm is a discrete differential operator that specifies the values of the first derivative of the periodic function in the selected set of points on the basis of the values of that function in the same set of points. It creates algebraic equations describing the steady-state solution for the nonlinear differential equations describing electromechanical systems. In this paper, the direct time-domain approach is tested for the simple converter considering. The algorithm used in this paper is competitive with respect to the one known in literature an approach based on the harmonic balance method operated in frequency domain.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 5; 645-653
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fabrication of a test rig for gearbox fault simulation and diagnosis
    Autorzy:
    Dubaish, Asaad Abdulhussein
    Jaber, Alaa Abdulhady
    Powiązania:
    https://bibliotekanauki.pl/articles/2203635.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    fault detection
    vibration analysis
    time-domain signal
    gearbox
    LabVIEW
    wykrywanie uszkodzeń
    analiza drgań
    przekładnia
    Opis:
    Gearboxes are one of the most important and widely exposed to different types of faults in machines. Therefore, manufacturers and researchers have made significant efforts to develop different fault detection and diagnostic approaches for gearboxes. However, many research foundations, such as universities, are currently working on developing different gearbox test rigs to understand the failure mechanisms in gearboxes. As a result, in this article, a gearbox testing rig was proposed and fabricated to evaluate gear performance under lowspeed working conditions. It describes the primary mechanical apparatus and the measurement tools used during the experimental analysis of a multistage gearbox transmission system. The data-gathering equipment used to acquire the observed vibration data is also discussed. LabVIEW software was used to build a data acquisition platform using an accelerometer and a NI DAQ device. Then different vibration tests were conducted under different operating conditions, when the gearbox was healthy and then faulty, on this test rig, and the gathered vibration data were analyzed based on time domain signal analysis. The preliminary results are promising and open the horizon for simulating different gearbox test scenarios.
    Źródło:
    Diagnostyka; 2023, 24, 2; art. no. 2023204
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time Domain Measurement Representation in Computer System Diagnostics and Performance Analysis
    Autorzy:
    Wideł, S.
    Flak, J.
    Gaj, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/384100.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    Time Domain Measurement Representation
    Computer System Diagnostics
    Opis:
    Time analysis is a common approach for testing and detecting methods for the performance analysis of computer systems. In the article it is shown, that measuring and identifying performances based on a benchmark is not sufficient for the proper analysis of the computer systems behavior. The response time of the process is often composed of the execution of many subprocesses or many paths of execution. Under this assumption, it is presented, that both convolution and deconvolution methods can be helpful in obtaining time distributions and modeling of complex processes. In such a modeling the analysis of measurement errors is very important and was taken into consideration. The example of using the methods in buffering process is also discussed.
    Źródło:
    e-Informatica Software Engineering Journal; 2013, 7, 1; 53-64
    1897-7979
    Pojawia się w:
    e-Informatica Software Engineering Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis and Modeling of Domain Registration Process
    Autorzy:
    Arabas, P.
    Jaskóła, P.
    Kamola, M.
    Karpowicz, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/309217.pdf
    Data publikacji:
    2012
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    domain market
    domain registration
    forecasting
    time series modeling
    Opis:
    The paper presents analysis of the domain name reservation process for the polish .pl domain. Two models of various time scale are constructed and finally combined to build long range high resolution model. The results of prediction are verified using real data.
    Źródło:
    Journal of Telecommunications and Information Technology; 2012, 2; 63-73
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of the electromagnetic response of complex dispersive material with the single-step wideband finite element method
    Autorzy:
    Butryło, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/141234.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    propagation of electromagnetic pulse
    dielectric dispersion
    frequency selective materials
    broadband time-domain simulation
    finite element time-domain method
    Opis:
    The paper describes the formulation and implementation of the broadband finite element time domain algorithm. The presented formalism is valid to analysis of electromagnetic phenomena in linear, frequency selective materials. The complex profile of permittivity of materials is approximated using a set of the Lorentz resonance models. The solution of the integro-differential second order equation is obtained using a singlestep integration scheme and a recursive convolution algorithm. The discussed formulation enables to adopt the structure of the narrowband part as well as the phase of calculation of the convolution equations for the subsequent components. The properties of the algorithm are validated using a finite difference broadband algorithm.
    Źródło:
    Archives of Electrical Engineering; 2013, 62, 1; 111-122
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The wave transformer – analysis and application of time digital filters and the integral-derivative operators of ½ order
    Autorzy:
    Siwczyński, M.
    Drwal, A.
    Żaba, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/141515.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wave transformer
    integral-derivative operators of fractional order
    convolution operators
    time domain
    digital filters
    Opis:
    In this paper the way of modeling phenomena occurring during the voltage and current waves passing through a point connection of two lines, with different wave impedance operators, is presented. This connection point is called „the wave transformer”. The analyzes and the resulting formulas concern not the frequency domain, but the time domain. The appropriate transition matrices of waves through the wave transformer are defined. This matrices are the convolution integral-derivative operators of fractional order (the digital filters). For a lossless line the wave transition matrices through the wave transformer become number type instead of operator type. All matrix multiplications occurring in the formulas should be understood in convolution way.
    Źródło:
    Archives of Electrical Engineering; 2013, 62, 3; 497-504
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling and analysis of fibre microlenses with ray-tracing and finite-difference methods
    Autorzy:
    Śliwak, Adam
    Jeleń, Mateusz
    Patela, Sergiusz
    Powiązania:
    https://bibliotekanauki.pl/articles/2063899.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
    Tematy:
    Finite-difference time-domain method
    knife-edge method
    microlens
    raytracing
    Opis:
    Fibre optic microlenses are small optical elements formed on the end-faces of optical fibres. Their dimensions range from a few tens to hundreds of micrometres. In the article, four optical fibre microlenses are modelled and analysed. Microlenses are used for light beam manipulation and quantitative metrics are needed to evaluate the results, for example, the size of focusing spot or intensity distribution. All four lenses tested are made of rods of the same refractive index; they were welded to a single-mode fibre. Two modelling methods were used to analyse the lenses: ray-tracing and finite-difference time-domain. The ray-tracing algorithm moves rays from one plane to another and refracts them on the surfaces. Finite-difference time-domain consists of calculating Maxwell’s equations by replacing spatial and temporal derivatives by quotients of finite differences. In this paper, the results of the microlenses analyses obtained from ray-tracing and finite-difference timedomain methods were compared. Both mets of analysis showed the presence of undesirable side lobes related to lens design, namely rods too long for lens fabrication. The test results were compared with the measurements made with the knife-edge method. The use of a single tool to determine parameters of an optical fibre lens does not allow for precise determination of its properties. It is necessary to use different tools and programs. This allows a complete analysis of the beam parameters, letting us find the causes of technical issues that limit the performance of the lenses.
    Źródło:
    Opto-Electronics Review; 2022, 30, 1; 1--9
    1230-3402
    Pojawia się w:
    Opto-Electronics Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of Transients in a Three-Level DC–DC Flying Capacitor Converter. Time Domain Approach
    Autorzy:
    Reznikov, Boris
    Ruderman, Alexander
    Galanina, Valentina
    Powiązania:
    https://bibliotekanauki.pl/articles/1193695.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    three-level DC–DC converter
    flying capacitor
    transient
    natural balancing
    Opis:
    The paper considers a discrete state-space model for transients in a three-level flying capacitor DC–DC converter. A transition matrix is obtained for a pulse width modulation (PWM) period. The matrix elements are expanded into a power series using a selected small parameter. The matrix eigenvalues that determine the natural balancing dynamics transients are presented in the form of power series as well. Four separate transients are constructed based on four possible PWM period initial states (topologies). Inductor current and capacitor voltage transients are found for the voltage source power-up as the arithmetic average of the four separate transients. The discrete solutions are replaced by continuous ones. The resulting transients that are elementary functions of the circuit parameters, PWM period, and voltage reference demonstrate good agreement with the simulation results.
    Źródło:
    Power Electronics and Drives; 2019, 4, 39; 33-45
    2451-0262
    2543-4292
    Pojawia się w:
    Power Electronics and Drives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Using FDTD method to the analysis of electric field intensity inside complex building constructions
    Autorzy:
    Choroszucho, Agnieszka
    Stankiewicz, Jacek Maciej
    Powiązania:
    https://bibliotekanauki.pl/articles/378245.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
    Tematy:
    finite-difference time-domain method (FDTD)
    wireless communications
    systems
    electromagnetic wave propagation
    building materials
    Opis:
    The aim of this article is to make a detailed analysis of the influence of the reinforcement diameter, the number of rows of reinforcing bars and the spacing between them for the values of the electric field intensity. The subject of the research is a model containing a wall made of concrete (dielectric) and reinforcement (conductor). Four reinforcement systems commonly used in building construction have been analysed. In addition, the influence of symmetry and asymmetry in the structure of bars on the values of field intensity determined for non-homogeneous material structures (reinforced concrete) was considered. For comparison, a concrete wall, without reinforcement (homogeneous material) was also analysed. Using FDTD method, the maximum electric field values generated by the Wi-Fi operating at the f = 2.4 GHz were calculated.
    Źródło:
    Poznan University of Technology Academic Journals. Electrical Engineering; 2019, 97; 39-48
    1897-0737
    Pojawia się w:
    Poznan University of Technology Academic Journals. Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An analysis of Chosen Image Formation Algorithms for Synthetic Aperture Radar with FMCW
    Autorzy:
    Okoń-Fąfara, M.
    Serafin, P.
    Kawalec, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/227061.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    signal processing
    synthetic aperture radar
    time domain correlation
    range-Doppler algorithm
    range migration algorithm
    Opis:
    The modelling of FMCW SAR systems, due to long signal duration time, commonly used start-stop approximation for pulsed radars causes errors in the image. Continuous motion of the radar platform results in additional range-azimuth couplings and range walk term that should be considered in processing of signal from this type of radar. The paper presents an analysis of the following algorithms: Time Domain Correlation (TDC), Range Doppler Algorithm (RDA), and Range Migration Algorithm (RMA). The comparison of the algorithms is based on theoretical estimation of their computation complexity and the quality of images obtained on the basis of real signals of FMCW SAR systems.
    Źródło:
    International Journal of Electronics and Telecommunications; 2016, 62, 4; 323-328
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of Transients in a 4-Level Flying Capacitor Converter: Time Domain Approach. Part 2: Small Normalised Voltage Command
    Autorzy:
    Reznikov, Boris
    Ruderman, Alex
    Galanina, Valentina
    Powiązania:
    https://bibliotekanauki.pl/articles/1193863.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    4-level DC–DC converter
    flying capacitor
    natural balancing
    transients
    Opis:
    A 4-level flying capacitor converter (FCC) operation is considered on a base of discrete state-space model. A transition matrix is obtained for a pulse width modulation (PWM) period for small normalised voltage command values [0, 1/3]. The transition matrix elements are expanded into power series by small parameters. The matrix eigenvalues are presented in the form of power series as well. Six separate transients are constructed for six possible initial FCC states on a PWM period. Inductor current and capacitors’ voltage transients are found for the voltage source power-up as the arithmetic average of the six separate transients. Finally, the discrete solutions are replaced by equivalent continuous ones. Simple and accurate formulas for inductor current and capacitors’ voltage transients demonstrate good agreement with simulation results.
    Źródło:
    Power Electronics and Drives; 2020, 5, 40; 41-57
    2451-0262
    2543-4292
    Pojawia się w:
    Power Electronics and Drives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of Transients in a 4-Level Flying Capacitor Converter: Time Domain Approach. Part 1: Large Normalised Voltage Command
    Autorzy:
    Reznikov, Boris
    Ruderman, Alex
    Galanina, Valentina
    Powiązania:
    https://bibliotekanauki.pl/articles/1193906.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    4-level DC-DC converter
    flying capacitor
    natural balancing
    transients
    Opis:
    A 4-level flying capacitor converter (FCC) operation is considered on a base of discrete state-space model. A transition matrix is obtained for a pulse width modulation (PWM) period for large normalised voltage command values [1/3, 1). The transition matrix elements are expanded into power series by small parameters. The matrix eigenvalues are presented in the form of power series as well. Six separate transients are constructed for six possible initial FCC states on a PWM period. Inductor current and capacitors’ voltage transients are found for the voltage source power-up as the arithmetic average of the six separate transients. Finally, the discrete solutions are replaced by equivalent continuous ones. Simple and accurate formulas for inductor current and capacitors’ voltage transients demonstrate good agreement with simulation results.
    Źródło:
    Power Electronics and Drives; 2020, 5, 40; 27-40
    2451-0262
    2543-4292
    Pojawia się w:
    Power Electronics and Drives
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Active Transient Sound Radiation Control from a Smart Piezocomposite Hollow Cylinder
    Autorzy:
    Hasheminejad, S. M.
    Rabbani, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/177572.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    active structural acoustic control (ASAC) thick cylindrical shells
    exact elasto-acoustic analysis
    time-domain solution
    intelligent system
    sound field attenuation
    Opis:
    The linear 3D piezoelasticity theory along with active damping control (ADC) strategy are applied for non-stationary vibroacoustic response suppression of a doubly fluid-loaded functionally graded piezolaminated (FGPM) composite hollow cylinder of infinite length under general time-varying excitations. The control gain parameters are identified and tuned using Genetic Algorithm (GA) with a multi-objective performance index that constrains the key elasto-acoustic system parameters and control voltage. The uncontrolled and controlled time response histories due to a pair of equal and opposite impulsive external point loads are calculated by means of Durbin’s numerical inverse Laplace transform algorithm. Numerical simulations demonstrate the superior (good) performance of the GA-optimized distributed active damping control system in effective attenuation of sound pressure transients radiated into the internal (external) acoustic space for two basic control configurations. Also, some interesting features of the transient fluid-structure interaction control problem are illustrated via proper 2D time domain images and animations of the 3D sound field. Limiting cases are considered and accuracy of the formulation is established with the aid of a commercial finite element package as well as comparisons with the current literature.
    Źródło:
    Archives of Acoustics; 2015, 40, 3; 359-381
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analiza metod pomiarów zaburzeń przewodzonych EMC z wykorzystaniem pakietu Mathematica
    Analysis of EMC measuring methods for conducted interference with use of Mathematica package
    Autorzy:
    Duzinkiewicz, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/157946.pdf
    Data publikacji:
    2012
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    pomiary w dziedzinie czasu i częstotliwości
    EMC
    zaburzenia przewodzone
    transformata Fouriera
    okno czasowe
    measurements in time and frequency domain
    conducted interferences
    Fourier transform
    time window
    Opis:
    W artykule przedstawiono pozanormatywne metody pomiarów zaburzeń przewodzonych EMC na przykładzie zasilacza impulsowego AC/DC. Wykonano analizę porównawczą znormalizowanych pomiarów kompatybilności elektromagnetycznej zaburzeń przewodzonych wykonywanych specjalizowanym odbiornikiem pomiarowym EMC z badaniami pozanormatywnymi wykonanymi w dziedzinie czasu za pomocą oscyloskopu cyfrowego. Do obliczeń numerycznych i wizualizacji wyników pomiarów wykorzystano pakiet Wolfram Mathematica 8. Przeprowadzona analiza wykazała porównywalne wyniki pomiarów obu metod.
    This paper presents the comparative analysis of measurements of conducted interferences taken with an EMI test receiver [5] (Fig. 1) according to norm [4] (PN-EN 55014) and non-normative measurements made by means of a digital oscilloscope (Fig. 2) in time domain. The investigations were carried out on an AC/DC supplying converter, commonly used in a low power chip TNY266 [6] (Fig. 4). Section 2 describes the measurement tests performed with the digital oscilloscope. Section 3 presents analytical transformations of signals from the time domain (Fig. 5) into the frequency domain (Fig. 6). Section 4 deals with a mathematical model of transforming [8] the sinusoidal signal with a third harmonic (Fig. 7) to the form of the frequency spectrum by means of a time window (Fig. 9). Use of time windows in real signal transformations is shown in Section 5 (Fig. 10). The signal frequency spectrum in electromagnetic compatibility research [1, 2] determines one of the most important ways of describing the level of disturbances emitted by electric and electronic equipment. Therefore the analysis results are shown on the same diagram (Fig. 11) in the frequency domain: the signal frequency spectrum of interferences measured with the EMI test receiver as well as the signal frequency spectrum obtained analytically. Numerical calculations and visualization of the measurement results were made with Wolfram Mathematic 8 packet. The analysis results show that there are slight differences between those two methods.
    Źródło:
    Pomiary Automatyka Kontrola; 2012, R. 58, nr 9, 9; 801-804
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Czy proces depolimeryzacji celulozy wpływa na odpowiedź dielektryczną układu izolacyjnego papier-olej?
    Does the process of cellulose depolymerization affect the dielectric response of oil-paper insulation?
    Autorzy:
    Gielniak, J.
    Graczkowski, A.
    Mościcka-Grzesiak, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/153847.pdf
    Data publikacji:
    2011
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    izolacja celulozowa
    stopień polimeryzacji
    odpowiedź dielektryczna
    pomiary w dziedzinie czasu
    analiza w dziedzinie częstotliwości
    cellulose insulation
    polymerization degree
    dielectric response
    time domain measurements
    frequency domain analysis
    Opis:
    Celem pracy jest ocena wpływu stopnia polimeryzacji celulozy DP na odpowiedź dielektryczną układu izolacyjnego papier-olej. Obiektami badań były próbki preszpanowe nowe i starzone o stopniu polimeryzacji odpowiednio 1435 i 406. Badano odpowiedź dielektryczną w dziedzinie czasu i częstotliwości. Badania wykazały, że charakterystyki odpowiedzi dielektrycznej próbek nowych i zestarzonych, o identycznej zawartości wody są bardzo zbliżone. Ich różnice mieszczą się w granicach rozrzutu.
    Up to now the controversial and unsolved problem up has been evaluation of insulation ageing, using the dielectric response method. Figs. 1 and 2 show the influence of aging of oil impregnated paper samples on the dielectric response. However, it is not clear yet if these changes are caused by reducing DP or by ageing of by-products such as acids formed during the ageing [7, 8, 9, 10]. The purpose of this work is to evaluate the influence of the cellulose polymerization degree (DP) on the dielectric response. The research objects were new and aged press-board samples of the polymerization degree 1435 and 406, respectively (Tab. 2). The authors investigated the dielectric response in the time and frequency domains. Results concerning the frequency analysis are presented in Figs. 3 and 4. It can bee seen that increase in moisture from 0.5 % to 3.3 % causes a large shift of the dielectric response characteristics. On the other hand, decrease in DP from 1435 to 406 causes a small change of the characteristic shape. Figs. 5, 6 and 7 show investigation results of the recovery voltage. In this case, also the shift of the characteristics corresponding to the samples of different DP values is very small. From the presented investigations it follows that DP does not affect the quantities characterizing the recovery voltage, which are used in practice most often. The research showed that the dielectric response characteristics of new and aged samples, of different DP and identical water content are very close. Their differences are within the limits of statistical dispersion.
    Źródło:
    Pomiary Automatyka Kontrola; 2011, R. 57, nr 4, 4; 397-400
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Applications and Comparison of Continuous Wavelet Transforms on Analysis of A-wave Impulse Noise
    Autorzy:
    Qin, J.
    Sun, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/177117.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    continuous wavelet transform (CWT)
    impulse noise signal processing
    time-frequency domain
    temporal and spectral resolutions
    noise-induced hearing loss
    A-wave impulse noise
    Opis:
    Noise induced hearing loss (NIHL) is a serious occupational related health problem worldwide. The A-wave impulse noise could cause severe hearing loss, and characteristics of such kind of impulse noise in the joint time-frequency (T-F) domain are critical for evaluation of auditory hazard level. This study focuses on the analysis of A-wave impulse noise in the T-F domain using continual wavelet transforms. Three different wavelets, referring to Morlet, Mexican hat, and Meyer wavelets, were investigated and compared based on theoretical analysis and applications to experimental generated A-wave impulse noise signals. The underlying theory of continuous wavelet transform was given and the temporal and spectral resolutions were theoretically analyzed. The main results showed that the Mexican hat wavelet demonstrated significant advantages over the Morlet and Meyer wavelets for the characterization and analysis of the A-wave impulse noise. The results of this study provide useful information for applying wavelet transform on signal processing of the A-wave impulse noise.
    Źródło:
    Archives of Acoustics; 2015, 40, 4; 503-512
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of the influence of the complex structure of clay hollow bricks on the values of electric field intensity by using the FDTD method
    Autorzy:
    Choroszucho, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/140952.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    building materials
    electromagnetic waves propagation
    finite-difference time-domain method (FDTD)
    wireless communication systems
    Opis:
    The study presents the analysis of the effects occurring at the propagation of electromagnetic waves within an area containing non-ideal, non-homogenous and absorbing dielectric. The analysed models are connected with housing constructions and include single and double-layered walls made of clay hollow bricks. The influence of the size of holes, the contained clay mass percentage and conductivity of brick on the distribution of electric field is presented. Double-layered wall causes more heterogeneity in distribution of electric field and numerous maxima and minima to compare with singlelayered construction. The presented results refer to the electromagnetic field generated by a wireless communication system (Wi-Fi), operating within the standard frequencies (2.4 GHz and 5 GHz). A FDTD method was used to the analysis of electric field distribution. Also in this paper all formulations of difference method (FDTD) is presented. The possibilities of modifying the described method are indicated too. The obtained values of electric field intensity allow to determining the attenuation coefficient for different variants of the walls. Detailed analysis of influence of different types of building construction will make it possible to better understand the wave phenomena and counteract local fading at planning of wireless networks systems.
    Źródło:
    Archives of Electrical Engineering; 2016, 65, 4; 745-759
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analiza numeryczna i doświadczalna propagacji pola elektromagnetycznego w badaniach metodą georadarową
    Numerical and experimental analysis of electromagnetic field propagation for ground penetrating radar inspection
    Autorzy:
    Rucka, M.
    Lachowicz, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/390887.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
    Tematy:
    fale elektromagnetyczne
    georadar
    badania doświadczalne
    metoda różnic skończonych
    electromagnetic waves
    ground penetrating radar
    experimental investigations
    finite difference time domain method
    Opis:
    W pracy przedstawiono badania doświadczalne metodą georadarową oraz analizę numeryczną propagacji pola elektromagnetycznego. Przedmiotem badań eksperymentalnych była konstrukcja podłogi. Pomiary wykonano za pomocą georadaru o częstotliwości emitowanej fali równej 2 GHz. W artykule opisano także sposób numerycznego modelowania elektromagnetycznego pola falowego za pomocą metody różnic skończonych w dziedzinie czasu. Przedstawiono wyniki propagacji fali elektromagnetycznej w próbce żelbetowej dla przypadku jednowymiarowego.
    This paper presents experimental tests by using the GPR method and numerical analysis of electromagnetic field propagation. The object of the experimental research was a ground floor structure. An antenna of frequency of emitted waves equal to 2 GHz was used for measurements. The paper also describes the numerical modelling of electromagnetic field with the use of the finite difference time domain method. Results of propagation of electromagnetic waves in a one-dimensional reinforced concrete specimen were presented.
    Źródło:
    Budownictwo i Architektura; 2014, 13, 2; 307-315
    1899-0665
    Pojawia się w:
    Budownictwo i Architektura
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Manoeuvring areas to adapt ACAS for the maritime domain
    Autorzy:
    Baldauf, M.
    Mehdi, R.
    Deeb, H.
    Schröder-Hinrichs, J. U.
    Benedict, K.
    Krüger, C.
    Fischer, S.
    Gluch, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/135052.pdf
    Data publikacji:
    2015
    Wydawca:
    Akademia Morska w Szczecinie. Wydawnictwo AMSz
    Tematy:
    situation-dependent analysis
    risk assessment
    risk of collision
    collision probability
    prediction of manoeuvring areas
    potential areas of water
    fast time simulation
    Opis:
    Rapidly increasing numbers of ships and ship sizes pose an ever-growing challenge to the maritime industry. Although statistics indicate improved levels of safety in the industry which carries 90% of the world’s trade, the risk of navigational accidents, among other issues, remains a prime concern and priority (EMSA, 2010; 2014). In order to address these concerns, the authors turned to another high-risk industry for inspiration. Specifically, they turned to the aviation industry, which has often been used as a source of comparisons and ideas by researchers in the maritime domain. Keeping up with the trend, the authors of this paper turn to a tried-and-tested system used widely in modern aviation: the Airborne Collision Avoidance System (ACAS). The prime idea behind ACAS is to construct two virtual 3D zones around an aircraft. These zones are dynamic, and depend on the manoeuvring characteristics of a given aircraft. If the system detects an “intruder” (another aircraft) in either of the two well-defined virtual zones, it provides warnings and/or instructions to pilots of both aircraft to take certain precautionary or emergency measures. In the current paper, the authors explore whether or not such a system is feasible for use in the maritime domain and, if so, how. The paper provides a detailed analysis of the potential benefits and drawbacks of using an ACAS-like system onboard vessels. It also discusses possible means of implementation and integration with current equipment, and explores how the introduction of e-navigation may impact the proposed solution.
    Źródło:
    Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2015, 43 (115); 39-47
    1733-8670
    2392-0378
    Pojawia się w:
    Zeszyty Naukowe Akademii Morskiej w Szczecinie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-30 z 30

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