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Wyszukujesz frazę "spectrum" wg kryterium: Temat


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:
Spectrum Allocation Policy in Elastic Optical Networks
Autorzy:
Olszewski, I.
Powiązania:
https://bibliotekanauki.pl/articles/227011.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
routing and spectrum allocation problem (RSA)
spectrum fragmentation
orthogonal frequency-division multiplexing (OFDM)
Opis:
The considered problem covers routing and spectrum allocation problem (RSA problem) in Elastic Optical Networks while maintaining the spectrum continuity constraints, non-overlapping spectra constraints for adjacent connections on individual links of the network and spectrum contiguity constraints of the connection. In this article the modified version of the First Fit spectrum slot allocation policy for Fixed Alternate Routing in flexible optical networks has been proposed. The Fixed Alternate Routing with proposed spectrum allocation policy rejects fewer requests, provides less bandwidth blocking probability and less spectrum fragmentation than Fixed Alternate Routing with well-known First Fit and Exact Fit spectrum allocation policies. However, the cost of improving these parameters is a higher computational complexity of the proposed allocation policy.
Źródło:
International Journal of Electronics and Telecommunications; 2017, 63, 4; 423-429
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automatic Test Bench for Selected Transmission Parameters of Power Line Conductors
Autorzy:
Chruszczyk, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/227032.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LabVIEW
power line measurements
power line communication
amplitude spectrum
phase spectrum
crosstalk measurement
Opis:
This paper presents automatic test bench used for measurement of selected high frequency parameters of a power copper line. The aim is fast estimation of line behavior in context of Power Line Communication (PLC). The hardware interface uses sinusoidal waveform generator, digital oscilloscope and a PC-class computer. The software interface created in LabVIEW environment performs signal processing and data presentation.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 1; 59-65
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Standard deviation in the simulation of statistical measurements
Autorzy:
Przystupa, Krzysztof
Kolodiy, Zenoviy
Yatsyshyn, Svyatoslav
Majewski, Jacek
Khoma, Yuriy
Petrovska, Iryna
Lasarenko, Serhiy
Hut, Taras
Powiązania:
https://bibliotekanauki.pl/articles/2203365.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
standard deviation
measurement
relaxation time
energy spectrum
Opis:
Is this article simulation of statistical measurements is performed on the basis of which the analysis of the standard deviation of the obtained results is carried out. It is shown that the standard deviation is minimum and independent from measurement duration while an object is in the state of equilibrium. For objects in a stationary non-equilibrium state the standard deviation depends on the duration measurements and the parameters of the state. The influence of these factors on the standard deviation is assessed with equation which includes the relaxation time. The value of the relaxation time is determined by approximating the energy spectrum of the studied signals. The analysis of energy spectra showed that the spectrum of white noise is inherent in objects in equilibrium; the flicker component of the spectrum occurs when the state of the object deviates from equilibrium.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 17--30
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Velocity measurement using the FDOA Method in ground-based radio navigation system
Autorzy:
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/221491.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radio navigation
spread spectrum
velocity estimation
FDOA
Opis:
Velocity is one of the main navigation parameters of moving objects. However some systems of position estimation using radio wave measurements cannot provide velocity data due to limitation of their performance. In this paper a velocity measurement method for the DS-CDMA radio navigation system is proposed, which does not require full synchronization of reference stations carrier frequencies. The article presents basics of FDOA (frequency difference of arrival) velocity measurements together with application of this method to an experimental radio navigation system called AEGIR and with some suggestions about the possibility to implement such FDOA measurements in other kinds of asynchronous DS-CDMA radio networks. The main part of this paper present results of performance evaluation of the proposed method, based on laboratory measurements.
Źródło:
Metrology and Measurement Systems; 2014, 21, 2; 363-376
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Experimental Study of Conducted EMI Mitigation on the LED Driver using Spread Spectrum Technique
Autorzy:
Yanuar, M. H.
Hidayat, R.
Firmansyah, E.
Powiązania:
https://bibliotekanauki.pl/articles/226428.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LED driver
conducted
EMI
luminance
spread spectrum
Opis:
LED driver has the potential to interfere the system of electronic devices if the voltage and current change rapidly. Several previous studies presented various solutions to overcome this problem such as particular converter design, component design, electromagnetic interference (EMI) filters, and spread-spectrum techniques. Compared to other solutions, the spread-spectrum technique is the most potential way to reduce the EMI in LED applications due to its limited cost-size-weight. In this paper, the effectiveness of conducted EMI suppression performance and the evaluation of its effect on LED luminance using spread-spectrum techniques are investigated. Spread-spectrum is applied to the system by modifying the switching frequency by providing disturbances at pin IADJ. The disorder is given in the form of four signals, namely square, filtered-square, triangular, and sine disturbance signals. The highest level of the EMI suppression of about 31.89% is achieved when the LED driver is given 800 mVpp filtered-square waveform. The highest reduction power level occurs at fundamental frequency reference, when it is given 700 mVpp square disruption signal, is about 81.77% reduction. The LED luminance level will reduce by 85.2% when it is given the four waveforms disruption signals. These reductions occur as the switching frequency of the LED driver does not work on a fixed frequency, but it varies in certain bands. LED brightness level has a tendency to generate a constant value of 235 lux when it is given the disruption signals. This disturbance signal causes the dimming function on the system that does not work properly.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 3; 293-299
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Centralized Spectrum Sharing and Coordination Between Terrestrial and Aerial Base Stations of 3GPP-Based 5G Networks
Autorzy:
Bechta, Kamil
Powiązania:
https://bibliotekanauki.pl/articles/1844695.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
5G
spectrum sharing
unmanned aerial vehicle
Opis:
The objective of this paper is to estimate performance of a new approach for spectrum sharing and coordination between terrestrial base stations (BS) and On-board radio access nodes (UxNB) carried by Unmanned Aerial Vehicles (UAV). This approach employs an artificial intelligence (AI) based algorithm implemented in a centralized controller. According to the assessment based on the latest specifications of 3rd Generation Partnership Project (3GPP) the newly defined Unmanned Aerial System Traffic Management (UTM) is feasible to implement and utilize an algorithm for dynamic and efficient distribution of available radio resources between all radio nodes involved in process of optimization. An example of proprietary algorithm has been described, which is based on the principles of Kohonen neural networks. The algorithm has been used in simulation scenario to illustrate the performance of the novel approach of centralized radio channels allocation between terrestrial BSs and UxNBs deployed in 3GPP-defined rural macro (RMa) environment. Simulation results indicate that at least 85% of simulated downlink (DL) transmissions are gaining additional channel bandwidth if presented algorithm is used for spectrum distribution between terrestrial BSs and UxNBs instead of baseline soft frequency re-use (SFR) approach.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 2; 301-308
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assignability of numerical characteristics of time-varying systems
Autorzy:
Babiarz, A.
Czornik, A.
Klamka, J.
Powiązania:
https://bibliotekanauki.pl/articles/201070.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
assignability
controllability
Lyapunov spectrum
linear time-varying systems
Opis:
The main aim of this article is to survey and discuss the existing state of art concerning the assignability by a feedback of numerical characteristics of linear continuous and discrete time-varying systems. Most of the results present necessary or sufficient conditions for different formulation of the Lyapunov spectrum assignability problem. These conditions are expressed in terms of various controllability types and optimalizability of the controlled systems and certain properties of the free system such as: regularity, diagonalizability, boundness away, integral separation and reducibility.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 6; 1007-1022
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling the One Channel Systems of a Delivery of Goods Provided by Unmanned Aerial Vehicles
Autorzy:
Kvyetnyy, Roman N.
Kulyk, Yaroslav A.
Knysh, Bogdan P.
Ivanov, Yuryy Yu.
Smolarz, Andrzej
Mamyrbaev, Orken
Burlibayev, Aimurat
Powiązania:
https://bibliotekanauki.pl/articles/226728.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal processing
window transformation
multi-window spectrum estimation
Opis:
In this article is revealed the systems of a good delivery witch implement unmanned aerial vehicles during providing the service. the one channel systems of a goods delivery are a goal of this research work. the close analysing of their functional features, the classification, the types and parameters of different systems from this band are presented. in addition, the modelling of the different types of the one channel systems of goods delivery are has done.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 3; 487-492
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stimulus with limited band optimization for analogue circuit testing
Autorzy:
Golonek, T.
Jantos, P.
Rutkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/221641.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analogue circuit testing
faults isolation
evolutionary computations
amplitude spectrum
Opis:
The paper presents an analogue circuit testing method that engages the analysis of the time response to a nonperiodic stimulus specialized for the verification of selected specifications. The decision about the current circuit diagnostic state depends on an amplitude spectrum decomposition of the time response measured during the test. A shape of the test excitation spectrum is optimized with the use of a differential evolution algorithm and it allows for achieving maximum fault coverage and the optimal conditions for fault isolation. Genotypes of the evolutionary system encode the amplitude spectrum of candidates for testing stimuli by means of rectangle frequency windows with amplitudes determined evolutionarily.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 73-84
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Employing a Savitzky-Golay Filtering Stage to Improve Performance of Spectrum Sensing in CR Applications Concerning VDSA Approach
Autorzy:
Angrisani, L.
Capriglione, D.
Cerro, G.
Ferrigno, L.
Miele, G.
Powiązania:
https://bibliotekanauki.pl/articles/220369.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cognitive radio
smoothing filter
VDSA
spectrum sensing
spectral measurements
Opis:
In this paper, a filtering stage based on employing a Savitzky-Golay (SG) filter is proposed to be used in the spectrum sensing phase of a Cognitive Radio (CR) communication paradigm for Vehicular Dynamic Spectrum Access (VDSA). It is used to smooth the acquired spectra, which constitute the input for a spectrum sensing algorithm. The sensing phase is necessary, since VDSA is based on an opportunistic approach to the spectral resource, and the opportunities are represented by the user-free spectrum zones, to be detected through the sensing phase. Each filter typology presents peculiarities in terms of its computational cost, de-noising ability and signal shape reconstruction. The SG filtering properties are compared with those of the linear Moving Average (MA) filter, widely used in the CR framework. Important improvements are proposed.
Źródło:
Metrology and Measurement Systems; 2016, 23, 2; 295-308
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal Spectrum Utilization and Flow Controlling In Heterogeneous Network with Reconfigurable Devices
Autorzy:
Hashmi, S. S.
Sattar, S. A.
Soundararajan, K.
Powiązania:
https://bibliotekanauki.pl/articles/226380.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rate-inference optimization
heterogeneous network
flow control
spectrum utilization
Opis:
Fairness provisioning in heterogeneous networks is a prime issue for high-rate data flow, wherein the inter-connectivity property among different communication devices provides higher throughput. In Hetnet, optimal resource utilization is required for efficient resource usage. Proper resource allocation in such a network led to higher data flow performance for real-time applications. In view of optimal resource allocation, a resource utilization approach for a reconfigurable cognitive device with spectrum sensing capability is proposed in this paper. The allocation of the data flow rate at device level is proposed for optimization of network fairness in a heterogeneous network. A dynamic approach of rate-inference optimization is proposed to provide fairness in dynamic data traffic conditions. The simulation results validate the improvement in offered quality in comparison to multi-attribute optimization.
Źródło:
International Journal of Electronics and Telecommunications; 2017, 63, 3; 269-277
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simulation for Detecting Nonlinear Echoes from Microbubbles Packets
Autorzy:
Ali, M. G. S.
Elsayed, N. Z.
Eid, E. A.
Powiązania:
https://bibliotekanauki.pl/articles/177697.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microbubbles packets
harmonic component
acoustic
radial dynamic
pressure spectrum
Opis:
This work presents a simulation of the response of packets of microbubbles in an ultrasonic pulse-echo scan line. Rayleigh-Plesset equation has been used to predict the echo from numerically obtained radial dynamics of microbubbles. Varying the number of scattering microbubbles on the pulse wave form has been discussed. To improve microbubble-specific imaging at high frequencies, the subharmonic and second harmonic signals from individual microbubbles as well as microbubbles packets were simulated as a function of size and pressure. Two different modes of harmonic generation have been distinguished. The strength and bandwidth of the subharmonic component in the scattering spectrum of microbubbles is greater than that of the second harmonic. The pressure spectra provide quantitative and detailed information on the dynamic behaviour of ultrasound contrast agent microbubbles packet.
Źródło:
Archives of Acoustics; 2015, 40, 2; 151-157
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reconstruction of Strains with a Non-smooth Distribution and Temperature Using Optical Fiber Bragg Grating
Autorzy:
Detka, Małgorzata
Kaczmarek, Cezary
Powiązania:
https://bibliotekanauki.pl/articles/2124758.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fiber Bragg grating
non-smooth strain distribution
reflection spectrum
Opis:
This paper presents a simulation study of the simultaneous reconstruction of the non-smooth strain distribution of an optical fiber Bragg grating and its temperature, which is based on the reflection spectrum of the reflected beam of the grating. The transition matrix method was used to model the reflection spectrum of the grating, and the nonlinear NelderMead optimization method was used to simultaneously reconstruct the strain distribution along the grating and its temperature. The results of simulations of simultaneous reconstruction of the strain profile and temperature indicate good accord with the strain profiles and temperature set. The reconstruction errors of the strain profiles are less than 1.2 percent and the temperature change errors are less than 0.2 percent, with a noise level of 5 percent.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 3; 535--540
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving the Consistency and Continuity of MODIS 8 Day Leaf Area Index Products
Autorzy:
Kandasamy, S.
Neveux, P.
Verger, A.
Buis, S.
Weiss, M.
Baret, F.
Powiązania:
https://bibliotekanauki.pl/articles/227345.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
iterative caterpillar singular spectrum analysis
MODIS
LAI
gap-filling
smoothing
Opis:
Time Series Analysis of Leaf Area Index (LAI) is vital to the understanding of global vegetation dynamics. The LAI time series derived from satellite observations are usually not complete and noisy due to cloud contamination and uncertainties in the retrieval techniques. In this paper, the continuity and consistency of the MODIS 8 day LAI products are improved using a method based on Caterpillar Singular Spectrum Analysis. The proposed method is compared with other standard methods: Savitzky-Golay filter, Empirical Mode Decomposition, Low Pass filtering and Asymmetric Gaussian fitting. The experiment demonstrates the smoothing and gapfilling ability of the developed method, which is more robust across the biomes both in terms of root mean square error metrics and bias metrics as compared to the standard methods.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 2; 141-146
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł

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