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Wyświetlanie 1-8 z 8
Tytuł:
Neural Classifiers of Vibroacoustic Signals in Implementation on Programmable Devices (FPGA) - Comparison
Autorzy:
Dąbrowski, D.
Cioch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1504200.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
45.80.+r
46.40.-f
Opis:
The research includes comparative analysis of the effect of the recording of weight vectors and input data of selected neural classifiers with fixed-point numbers. Research has been conducted due to insufficient literature on the influence of such a recording on the correct classification of vibroacoustic signals by neural networks. This current issue was brought up in authors' earlier researches, concerning realization of neural classifiers on programmable logical devices field programmable gate array, with the application of fixed-point processor. During the analysis, three types of neural classifiers were compared in the tests: classifier based on neural network - length vector quantization, classifier using radial neural networks - radial basis functions, and third - counter propagation neural network. The problem stated was to recognize technical state of gear transmission DMA-1 in variable operating conditions. Vectors, based on estimates derived from processed vibroacoustic signals were used as teaching material.
Źródło:
Acta Physica Polonica A; 2011, 119, 6A; 946-949
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Signals Pre-processing Algorithm in Case οf Hardware and Software Implementation οn Diagnostic Programmable Device PUD-2
Autorzy:
Dąbrowski, D.
Cioch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1400077.pdf
Data publikacji:
2013-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.80.+j
46.40.-f
Opis:
In the paper, two-stage signal pre-processing algorithm based on the filtration is presented. The developed algorithm is dedicated for the diagnostic programmable device PUD-2. The PUD-2 is the real-time analyzer based on programmable logic devices FPGA, as well as on ARM processor. Application of FPGA programmable devices and ARM processors allows to merge advantages of hardware and software implementations. Further, analysis of digital filters parameters in case of its efficient realization on the FPGA is presented. The aim of the study is to select digital-filter parameters in such way that the available resources of FPGA are used efficiently and filter characteristics meet established criteria. In the study, low pass finite impulse response and infinite impulse response filters are compared. For the first stage of the signal pre-processing algorithm, hardware implementation of the infinite impulse response filter is proposed, contrary to the second stage, where software realization of the finite impulse response filter is suggested. Combination of hardware and software filtration algorithms allows for fast and efficient realization of signal pre-processing algorithm used in analysis carried out on the PUD-2.
Źródło:
Acta Physica Polonica A; 2013, 123, 6; 1020-1023
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardware Implementation of Artificial Neural Networks for Vibroacoustic Signals Classification
Autorzy:
Dąbrowski, D.
Jamro, E.
Cioch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1537403.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
45.80.+r
46.40.-f
Opis:
This paper studies the architecture of a neural classifier designed to identify technical condition of machines, based on vibroacoustic signals. The designed neural network is optimized for implementation on Field Programmable Gate Arrays (FPGA) programmable devices. FPGA allows massive parallelism and thus real-time classification as each neuron can execute arithmetic operations simultaneously. The classifier of vibroacoustic signals was designed and tested for the self - organized neural network. The teaching vectors are based on estimates derived from processed vibroacoustic signals generated by rotary machines. The created classifier was applied for recognizing technical state of demonstrative toothed gear DMA1 in variable operating conditions.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 41-44
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of the Gears Based on Multibody System and Its Validation by Application of Non-Contact Methods
Autorzy:
Dąbrowski, D.
Batko, W.
Cioch, W.
Plascencia-Mora, H.
Powiązania:
https://bibliotekanauki.pl/articles/1400076.pdf
Data publikacji:
2013-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.80.+j
45.40.-f
Opis:
In the paper an application of laser measurements for validation of the gears dynamic model have been presented. The model of the gears was compared with an experimental data in case of diagnostics of manufacturing failures. The comparison was done on the basis of vibration signals generated by the model and the real object. In the experiment correct work as well as incorrect one of the gears was studied. Purpose of the paper is to compare the model with the experimental data; to this end, the Multibody model of the gears was build in MSC ADMS software. The model consists of two gears and two shafts, with both gears and shafts treated as rigid bodies, but contact surfaces between them are flexible. To conclude, in the study comparison of acceleration signals estimates behavior due to other gears faults in the experiment and in the model has been presented. For optimal model validation, laser measurements on the shaft in the experiment were conducted.
Źródło:
Acta Physica Polonica A; 2013, 123, 6; 1016-1019
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prenematic Self-Assembling of Mesogenic Molecules in Isotropic Liquid and Orientational Order in Nematic Phase
Autorzy:
Wolarz, E.
Bauman, D.
Jadżyn, J.
Dąbrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1493609.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
61.30.Gd
77.22.Ch
Opis:
Dielectric relaxation study of nematogenic 4-n-alkyl-4'-cyanobiphenyls (nCB, n = 5, 6), 4-(trans-4'-n-alkylcyclohexyl)isothiocyanatobenzenes (nCHBT, n = 6, 8), 4-cyanophenyl-4'-n-alkylbenzoates (nCPB, n = 6, 8), 4-cyano-3-fluorophenyl-4'-n-octyloxybenzoate (8OCFPB), and 4-cyanophenyl-4'-n-octyloxy-3'-fluorobenzoate (8OCPFB) was performed in the frequency range from 50 kHz to 100 MHz in the nematic and isotropic phases. The static permittivity and the relaxation process related to the rotation of molecules around their short axis was analyzed. For some of these liquid crystals anomalous temperature dependence of static permittivity in the pretransitional region of the isotropic phase was observed. Based on the Meier-Saupe-Martin model of molecular diffusion in nematics, the orientational order parameter 〈$P_2$〉 was determined from dielectric relaxation times and retardation factor. The values of 〈$P_2$〉 calculated from the dielectric relaxation data were compared with the results obtained from measurements of polarized electronic absorption. Correlations between the magnitude of the dielectric pretransitional effect and the orientational order in the nematic phase were discussed.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 447-454
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric Properties of Ferroelectric Liquid Crystals with Diversified Molecular Structure
Autorzy:
Czerwiec, J.
Dąbrowski, R.
Żurowska, M.
Ziobro, D.
Wróbel, S.
Powiązania:
https://bibliotekanauki.pl/articles/1538235.pdf
Data publikacji:
2010-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.84.Nh
78.15.+e
64.70.M-
Opis:
Mesomorphic, thermodynamic, electro-optic and dielectric properties of three homologues of fluorosubstituted esters are described. Full chemical names of these compounds are as follows: (S)-(+)-4-(1-metyl-hepty-loksy)benzoate-(6-penta-fluoro-propano-ynloxyhex-1-oxy)-biphenyl-4-yl (in short 2F6BBiOC8), (S)-(+)-4-(1-metyl-hepty-loksy)benzoate-(6-nona-fluoro-pentano-yloxyhex-1-oxy)-biphenyl-4-yl (in short 4F6BBiOC8), (S)-(+)-4-(1-metyl-hepty-loksy)benzoate-(6-trideca-fluoro-heptano-yloxyhex-1-oxy)-biphenyl-4-yl (in short 6F6BBiOC8). The compounds exhibit ferroelectric smectic C* phase between crystalline and isotropic phase. Only one compound (6F6BBiOC8) shows antiferroelectric phase $(SmC_{A}^\ast)$ observed by dielectric spectroscopy, but the range of this phase is narrow of about 2°. All three compounds exhibit in the SmC* phase Goldstone mode and Maxwell-Wagner relaxation hidden in the conductivity contribution at low frequencies, whereas in the $SmC_{A}^\ast$ phase two anti-ferroelectric modes (AFM1) and (AFM2) contribute to the dielectric spectrum. The compounds were studied using differential scanning calorimetric, frequency domain dielectric spectroscopy, and reversal currents method to determine spontaneous polarization.
Źródło:
Acta Physica Polonica A; 2010, 117, 4; 553-556
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of New Antiferroelectric Liquid Crystal Based on Quantum-Chemical Model
Autorzy:
Tomczyk, W.
Marzec, M.
Juszyńska, E.
Dąbrowski, R.
Ziobro, D.
Wróbel, S.
Massalska-Arodź, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399016.pdf
Data publikacji:
2013-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.84.Nh
64.70.M-
Opis:
Physical properties of new thermotropic antiferroelectric liquid crystal have been studied. Experiments were done by use of complementary methods such as differential scanning calorimetry, polarizing optical microscopy and X-ray powder diffractometry. Acquired data from X-ray powder diffractometry was examined under application of quantum chemical approach. It has been found that compound studied exhibits stable enantiotropic antiferroelectric SmC_{A}* phase in the wide temperature range while ferroelectric phase SmC* is very narrow.
Źródło:
Acta Physica Polonica A; 2013, 124, 6; 949-953
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photonic Liquid Crystal Fibers with Polymers
Autorzy:
Woliński, T.
Tefelska, M.
Mileńko, K.
Siarkowska, A.
Budaszewski, D.
Domański, A.
Ertman, S.
Orzechowski, K.
Rutkowska, K.
Sierakowski, M.
Nowinowski-Kruszelnicki, E.
Dąbrowski, R.
Mergo, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399416.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.81.Wg
02.60.Cb
42.70.Qs
Opis:
Photonic liquid crystal fibers with polymers constitute a new solution based on liquid crystals and microstructured polymer optical fibers opening up new areas in innovative sensing and photonic devices applications. Compared with their silica-based microstructured fibers, it is easier to fabricate exotic microstructured polymer optical fibers by extrusion or drilling at low temperature; their nonlinearity is potentially stronger, the range of available polymers that may be drawn is more diverse and the biocompatibility of polymers is often better. Liquid crystals due to their attractive properties i.e., the high birefringence, high electro-optic and thermo-optic effects are a very good candidate for microstructured polymer optical fiber infiltration to obtain tunable all-in-fiber innovative photonic devices. The paper will discuss basic properties and possible applications of the polymer photonic liquid crystal fibers that will arise from their high optical tunability with external and internal factors. Current research effort is directed towards two main solutions: photonic crystal fibers and microstructured polymer optical fiber-based structures, both infiltrated with liquid crystals of tailored optical properties.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 613-616
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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