Wyniki wyszukiwania - BazTech

1

Improving the Efficiency of UAV Communication Channels in the Context of Electronic Warfare

Semendiai Serhii, Tkach Yuliіa, Shelest Mykhailo, Korchenko Oleksander, Ziubina Ruslana, Veselska Olga

International Journal of Electronics and Telecommunications

|

2023

|

Vol. 69, No. 4

727--732

EN

The article is devoted to the development of a method for increasing the efficiency of communication channels of unmanned aerial vehicles (UAVs) in the conditions of electronic warfare (EW). The author analyses the threats that may be caused by the use of electronic warfare against autonomous UAVs. A review of some technologies that can be used to create original algorithms for countering electronic warfare and increasing the autonomy of UAVs on the battlefield is carried out. The structure of modern digital communication systems is considered. The requirements of unmanned aerial vehicle manufacturers for onboard electronic equipment are analyzed, and the choice of the hardware platform of the target radio system is justified. The main idea and novelty of the proposed method are highlighted. The creation of a model of a cognitive radio channel for UAVs is considered step by step. The main steps of modelling the spectral activity of electronic warfare equipment are proposed. The main criteria for choosing a free spectral range are determined. The type of neural network for use in the target cognitive radio system is substantiated. The idea of applying adaptive coding in UAV communication channels using multicomponent turbo codes in combination with neural networks, which are simultaneously used for cognitive radio, has been further developed.

2

Effects of harmonics and voltage unbalance on the behavior of a five-phase permanent magnet synchronous machine

Kebir Ahmed Amine, Ayad Mouloud, Kamel Saoudi

Archives of Electrical Engineering

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2022

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Vol. 71, nr 2

471--488

EN

The development in industrial systems leads to the augmentation in the consumption of the power. Therefore, this development makes use of multiphase machines. The use of multiphase machines caused several problems and defects. Electrical energy is mainly distributed in a three-phase system to provide the electrical power necessary for the electrical engineering equipment and materials. The sinusoidal aspect of the required original voltage primarily preserves its essential qualities for transmitting useful power to terminal equipment. When the voltage waveform is no longer sinusoidal, perturbations are encountered, which generate malfunctions and overheating of the receivers and the equipment connected to the same electrical supply network. The main disturbing phenomena are harmonics, voltage fluctuations, voltage unbalances, electromagnetic fields, and electrostatic discharges. This present work aims to study the effects of harmonic pollution and voltage unbalance on the five-phase permanent magnet synchronous machine using spectrum current analysis and wavelet transform.

3

Optyczna spektroskopia podczerwieni cienkich warstw FTIR - podstawy identyfikacji widm poliazometin

Hajduk Barbara, Jarka Paweł, Bednarski Henryk, Tański Tomasz, Woźniak Anna

LAB Laboratoria, Aparatura, Badania

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2021

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R. 26, nr 3

48--51

4

Determination of rheological model coefficients of pipeline composite material layers based on spectrum analysis and optimization

Bogdevičius Marijonas, Karpenko Mykola, Bogdevičius Paulius

Journal of Theoretical and Applied Mechanics

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2021

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Vol. 59 nr 2

265--278

EN

The article presents theoretical and experimental investigation on properties of a composite material based on rubber. The approach presented in this research is an experimental measurement based on spectrum analysis combined with theoretical investigation held to describe a viscous-elastic behaviour of the material. The proposed mathematical model is represented by five rheological parameters of hybrid Maxwell and Kelvin-Voigt elements and includes an optimization task for determination of the stiffness and damping coefficients. In the proposed rheological model, not only the displacements are unknown but also forces described by second-order differential equations. Validation between the experimental measurement and theoretical investigation is made based on spectrum analysis.

5

Analysis of the possibility of using markers emitting pulsating light in the task of localization

Miś Piotr, Szulim Przemysław

Applied Computer Science

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2021

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Vol. 17, no 1

26--39

EN

This work shows the possibility of using spectral analysis in order to detect characteristic points in recorded images. The specific point is a marker in the form of a diode that flashes at a certain frequency. Main assumptions of the processing algorithm are the recording of a sequence of images and treatment change of level of brightness for each pixel as a time signal. The amplitude spectrum is determined for each time signal. The result of data processing is an amplitude image whose pixels brightness corre-sponding to the intensity of source of pulsating light emitting specific frequency. This new data representation is used to detect position of markers. The algorithm was researched in order to select optimal marker colors and pulsation frequency. The results are described in a summary.

6

Spektroskopia Ramana w zakresie niskich częstotliwości w badaniach materiałów wybuchowych

Liszewska Malwina, Bartosewicz Bartosz, Budner Bogusław, Szala Mateusz, Miczuga Marcin, Kopczyński Krzysztof, Jankiewicz Bartłomiej J.

Przemysł Chemiczny

|

2020

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T. 99, nr 10

1469--1476

PL

Spektroskopia Ramana stała się w ostatnich latach jedną z ważniejszych technik analitycznych znajdujących zastosowanie w różnych sektorach gospodarki. Wynika to z braku konieczności preparowania próbek do badań, krótkiego czasu pomiaru oraz łatwej identyfikacji badanych substancji na podstawie charakterystycznych widm ramanowskich. W rejestrowanym widmie nieelastycznie rozproszonego światła można wyróżnić zakres 200–4000 cm-1, który odzwierciedla strukturę chemiczną cząsteczki (widmo oscylacyjno-rotacyjne), tzw. odcisk palca, oraz zakres 5–200 cm-1, zwany zakresem niskich częstotliwości, który dostarcza informacji o drganiach sieci krystalicznej w ciele stałym (widmo fononowe). Przedstawiono podstawowe informacje dotyczące spektroskopii Ramana w zakresie niskich częstotliwości, jej możliwości pomiarowych i aplikacyjnych oraz dokonano przeglądu literatury na temat zastosowania tej techniki w badaniach materiałów wybuchowych.

EN

Fundamentals and review with 68 refs.

7

Diagnostic benchmarks on dynamic characteristics of thin-walled marine damaged structures

Szeleziński Adam, Murawski Lech, Muc Adam

Multidisciplinary Aspects of Production Engineering

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2019

|

Vol. 2, Iss. 1

38--52

EN

Among structural health monitoring (SHM) methods of thin-walled structures, a vibrodiagnostic method is one of the most promising. The accelerometer recorded responses provide diagnostic information that requires mathematical processing to extract the essential dynamic characteristics. The authors have been looking for new parameters - diagnostic benchmarks which can be applied to non-destructive, automatic testing of thin-walled marine structures (especially their welded joints) like ship hulls. All characteristics have been based on recorded data generated during the vibration tests of welded joints with and without failures. For this purpose, the authors proposed method based on: FFT windowing analysis, benchmark with using 2D or 3D time – frequency dynamic characteristics and the determination of damping decrement in function of time. The work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds.

8

Vibroacoustic Testing of Power Transmission Units and Engines in W-3 Helicopters

Śniegóła Radosław

Journal of Mechanical and Transport Engineering

|

2019

|

Vol. 71, No 2

59--71

EN

In today's world, more and more importance is attached to the development of methods for diagnosing technical objects. Therefore, researches at the production and operation stage of machinery and equipment become increasingly important, taking into consideration the least involvement of forces and resources in the limited time for carrying out a diagnosis. It aims primarily at increasing the level of safety concerning operating technical objects, starting with individual devices up to entire systems.

PL

Wibroakustyka cieszy się coraz większym zainteresowaniem i coraz częściej wykorzystuje się ją jako metodę diagnozowania w technice, w tym również w technice lotniczej. Zastosowanie nowych metod przetwarzania sygnałów jak również coraz czulszych czujników wibroakustycznych pozwala przypuszczać, że metody związane z analizą sygnałów wibroakustycznych będą kluczowe w wielu dziedzinach techniki. Przykładem zastosowania w praktyce diagnozowania i badania obiektu technicznego z użyciem technik wibroakustycznych jest usankcjonowane biuletynami technicznymi badanie śmigłowca W-3, który - jak pokazuje praktyka eksploatacyjna - jest konstrukcją wysoce podatną i czułą wibracyjnie. Przytoczony w artykule przykład diagnostyki śmigłowca W-3 daje obraz szerokiego zastosowania tego typu metod diagnozowania, a także rozpoczyna serię prac nad stworzeniem modelu wibracyjnego tego typu statków powietrznych.

9

Light sources and their influence on vision organ

Otowski W., Lewińska G.

Technical Transactions

|

2017

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Vol. 4(114)

219--232

EN

The aim of the study was to compare light sources. The paper presents the spectrum of light intensity for natural and artificial sources. Analysis of the spectra was carried out because of their importance for the health of the eye.

PL

Celem artykułu jest porównanie źródeł światła. W pracy zostały zaprezentowane widma natężenia światła dla źródeł naturalnych i sztucznych. Przeprowadzona została analiza widm ze względu na ich znaczenie dla zdrowia narządu wzroku.

10

Deconvolution of alpha spectra from air filters applied for measurements of the short-lived radon progeny concentration

Skubacz K.

Nukleonika

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2017

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Vol. 62, No. 3

229--234

EN

The paper contains a description of a method for the analysis of the complex alpha spectra generated during the measurement of the activity of filters outside of a vacuum chamber under environmental conditions. The peaks corresponding to the energies of alpha particles emitted by the specific isotopes are particularly large on the low-energy side of the peak maximum, and the energy resolution strongly depended on the applied filters. The analysis was based on the non-linear regression to a function designed for four, six and eight parameters. Satisfactory results were obtained for each of these functions, and the best-fitting results were achieved for the eight-parameter function. In addition, the uncertainties related to the estimated parameters, as well as the signals corresponding to functions that describe the shape of the energy peak, have been evaluated. There are also examples of the implementation of the method with respect to short-lived radon progeny and thoron decay products.

11

Quality assessment of welded joints using the mean value distribution of amplitude spectrums calculated by the time window method

Szeleziński A., Muc A., Murawski L.

Journal of KONES

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2017

|

Vol. 24, No. 2

263--270

EN

In continuous monitoring systems of welded joints of thin-walled structures, a vibrodiagnostic method is the most promising. Its most important advantage is that it is effective and offers the greatest real-time research capabilities. It is used in classic NDT techniques as well as in structural health monitoring during exploitation. This work presents a measurement method of dynamic characteristics of the structure with the use of piezoelectric sensors. The article presents the assumptions concerning the evaluation of welded joints using the analysis of the mean value distribution of the amplitude spectrums calculated by the time window method. The statistical measure used in the form of the mean value is a proposed parameter. The parameter's analysis for a given welded joint may enable an unambiguous assessment of its quality. Attention was paid to the elements important for the study. A calculation algorithm as well as and the exemplary results from the proposed method used for some selected samples with different welds is included in the article. The work contains the description of the scientific apparatus to register dynamic characteristics in case of welded joints. The results of the tests show that the analysis of the distribution of mean value for amplitude spectrums calculated by the time window method indicates that they differ markedly depending on the welds, indicating their quality and defects that are associated with them.

12

Analysis concerning changes of structure damping in welded joints diagnostics

Szeleziński A., Muc A., Murawski L.

Journal of KONES

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2017

|

Vol. 24, No. 4

313--320

EN

Among non-destructive testing methods of welded joints, a vibrodiagnostic method is one of the most promising in applications intended for the continuous monitoring of the structure. The accelerometer-recorded responses provide diagnostic information that requires mathematical processing to extract the essential features typical of the tested welded joints and to evaluate their execution. For this purpose, the proposed method was based on the determination of damping decrement in function of time. Due to the complexity of the responses run, a proposed method consisted of calculating the damping decrement using the response approximation with different functions. It has been shown that the changes analysis of damping decrement applied to welded plates enables the assessment of the quality associated with the weld. Attention was also paid to the elements relevant to the study. This work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds. A scientific apparatus, which purpose was to record dynamic characteristics of welded joints was also described.

13

Metoda analizy widm mierzonych z wykorzystaniem spektrometrów OP-FTIR w monitorowaniu powietrza atmosferycznego oraz gazów w procesach przemysłowych

Cięszczyk S., Komada P., Akhmetova A., Mussabekova A.

Rocznik Ochrona Środowiska

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2016

|

Tom 18, cz. 2

218--234

EN

Open-Path Fourier Transform Infrared (OP-FTIR) can be used for monitoring of atmospheric environment. The open path technique is based on the measurement of the absorption along the atmosphere path between radiation source and spectrometer. Measurement paths used in this method have a considerable length – from tens of meters to several kilometers. The main advantage of OP-FTIR spectrometry is the possibility of continuously and simultaneously measuring concentrations of multiple compounds. Unfortunately, quantitative analysis of the spectra of such measurements is a difficult issue due to the changing atmospheric conditions and overlapping of the absorption spectra of various components. Numerous algorithms used for the interpretation of the measured spectra have been proposed. They can be classified into methods using classical chemometric calibration and iterative algorithms. Classical Least Square CLS and Partial Least Square PLS are the most commonly used methods of OP-FTIR spectrometry. Iterative methods are based on comparing measured data with synthetic spectra, that is computational models of investigated optical path transmission. For this purpose, databases such as HITRAN are used. Transmission model must take into account not only the spectral characteristics of gases, but also the measuring instrument influence on the measured spectrum. As an example of modeling the spectra of NH3 and HCl gas are used. Modeling of gas spectra with different resolution is shown. Classical methods of building a chemometric calibration model require appropriate reference samples. This is usually associated with considerable cost and time-consuming calibration process. In addition, correct calibration requires maintaining the same conditions during the calibration, as in practical measurements. This is possible only in the case of laboratory measurements. In particular, it is necessary to maintain a constant temperature and pressure of examined substances. It is connected with changes in width and intensity of gas rotational lines. In classical spectroscopy, changing environmental conditions require new calibration measurements. In the open path spectroscopy, changes in conditions occur naturally along with the changes in the examined environment (object, process). If the measurement conditions in the environment differ from those in calibration measurements, significant errors in determining the content of the ingredients may appear. Greater changes in conditions may occur in a variety of chemical or physical processes. Sometimes it is not possible to perform measurements in conditions similar to those occurring in a particular industrial facility. In such cases, synthetic spectra may be used in two ways: in an iterative process to compare with measured spectra or to form a chemometric calibration models. In the latter case, the problem of changing conditions can be solved in several ways. The simplest method is to build separate calibration models for all conditions that can occur during the measurement. However, in order to use this method, it is necessary to measure the existing conditions and choose an appropriate local model. Another method is to correct the measured spectra and to adapt them to the standard conditions. The third option is to build global models. The spectra of all the conditions that may occur during the measurement are then used for building a calibration model. Then, the effect of temperature on the determination of gas content for local calibration models is investigated. Finally, a global calibration model insensitive to temperature changes in 10-40°C range is built.

14

Mechanisms of electric arc detection based on current waveform spectrum and incremental decomposition analysis

Dołęgowski M., Szmajda M.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 11

59--62

EN

This paper presents two methods that enable arc detection, these are frequency analysis FFT and incremental decomposition of current increase in time. Both methods enable arc detection and provide additional information as compared to currently existing commercial solutions.

PL

W artykule zaprezentowano dwie metody umożliwiające wykrywanie występowania łuku elektrycznego: analizę częstotliwościową FFT oraz metodę badania rozkładu przyrostów prądu w czasie. Obydwie metody umożliwiają detekcję łuku oraz dostarczają dodatkowych informacji w stosunku do istniejących obecnie rozwiązań komercyjnych.

15

Analysis of ability to detect defects in welding structures with usage of dynamic characteristics spectrums

Szeleziński A., Murawski L., Muc A.

Journal of KONES

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2016

|

Vol. 23, No. 2

365--372

EN

Non-destructive methods of testing (NDT) welded joints are nowadays intensively developing due to their numerous advantages. The most significant of them are the possibility of objects diagnosis in the place of their work without the necessity of disassembling or long outage, lower costs of realization as well as considerably lower insalubrity for people conducting the tests. Study of dynamic characteristics of welded elements creates a good possibility for welded joints assessment in comparison to other known non-destructive testing methods. The main reasons are Fourier analysis (FFT), damping analysis, differences in signals or their answers. Presented method can be used in classical NDT tests as well as in structural health monitoring (SHM). Assumptions for quality evaluation methods of welded plates using spectrums analysis of dynamic characteristics are presented in the article. In order to provide the high quality of research, the measuring devices of Bruel & Kjaer Company are used. Both, the testing methodology and possibility of using vibration method in welded joints testing are presented. The attention is also drawn to the vital testing elements like proper selection of impact hammer ending and impact place as well as the problem of repeatability of diagnostic signals. The value of repeatability of obtained signals will be of critical importance in the comparative method, which is under development. The results of initial testing of plates with proper and faulty welded joints have been analysed. Among welding faults, the boundary bonding and crevice have been considered. The analysis of impact hammer dispersion values in correlation to the spectrum of dynamic characteristic has been conducted. Statistic methods have been used for the assessment.

16

Effect of the friction films’tribosynthesis mechanism on the antifriction properties of composite materials based on nickel

Roik T., Gavrish A., Vitsuk J.

Selected Engineering Problems

|

2015

|

nr 6

81--90

EN

In a paper the results of effect the friction films’ tribosynthesis mechanism on the antifriction properties of new composite materials based on nickel with solid lubricant CaF2 for high speed printing equipment have been presented. Paper generalizes the formation of antiscoring films, so called secondary structures, on the contact surfaces of the examined materials during friction process. Research of the friction surfaces was carried out using the method of Auger spectrum analysis. It was shown the mechanism of the antifriction films’ tribosynthesis depends on operation conditions, material and counterface chemical composition. It has been demonstrated that it is possible to predict and control the anti-friction properties of materials by technological means. To do this, it is necessary to choose a chemical composition of the friction pair, which could ensure the high functional properties, and could open a possibility purposefully to choose the operating conditions of the material in a printing equipment’s friction unit.

17

The most frequent shortcomings of Wi-Fi operators

Grenar M., Filka M.

Przegląd Elektrotechniczny

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2015

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R. 91, nr 6

129-133

EN

This paper is focused to the most frequent shortcomings of WiFi technology operators seen by monitoring of broadband data transmission in frequency bands 2.4 GHz up to 66 GHz. The used process of measuring an evaluation of measured data summarized by the devices used by Czech Telecommunication Office for inspection and supervision is performed next. The paper is concluded by real examples of various shortcomings and mistakes.

PL

W artykule analizowano najczęściej pojawiające się wady technologii WiFi występujące w paśmie 2.4 GHz - 66 GHz. Badano układy stosowane przez Czeski Urząd Telekomunikacji.

18

The approximate location of imperfection in a unit circle using the spectrum of Laplace operator as a research tool

Brzęk M., Zagórowska M., Mitkowski W.

Automatyka / Automatics

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2015

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Vol. 19, no. 1

9--15

EN

In the following article we will try to find the dependence between the location of imperfections in a closed domain and the spectrum of the Laplace operator for this region. In the theoretical part we will define the spectral problem which is solved by eigenvalues. These eigenvalues are dependent on location and size of the imperfection. However, we are interested in the inverse task which consists in localizing the imperfection of the domain on a basis of the spectrum of the operator.

PL

W artykule przeanalizowano zastosowanie widma operatora Laplace'a jako narzędzia do przybliżonej lokalizacji uszkodzeń w kole jednostkowym. W części teoretycznej zdefiniowano zagadnienie spektralne rozwiązywane za pomocą wartości własnych. Znalezione wartości zależą od położenia i rozmiaru uszkodzeń. W artykule został zdefiniowany problem odwrotny, który polega na znalezieniu miejsca uszkodzenia na podstawie znanego widma.

19

Komputerowe wspomaganie terapii logopedycznej

Kostrzewa B., Staszuk A.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2013

|

Vol. 19, nr 4

176--180

PL

Trudność wymowy głoski „r” sprawia, że dzieci uczą się jej jako ostatniej, dlatego znaczna część polskiego społeczeństwa nie wymawia tej głoski poprawnie. Powoduje to problemy w nauce (dysleksja), jak również odbija się na życiu emocjonalnymi i społecznym. Bagatelizowany problem doskwiera również w dorosłym życiu, powodując częste kompleksy, które mogą wpływać niekorzystnie na zdrowie osób cierpiących na wadę wymowy. Przyczynia się także do rozwoju chorób cywilizacyjnych, takich jak depresja czy nerwica. Aby ułatwić osobom dorosłym naukę wymowy głoski „r”, stworzono specjalną aplikację wspierającą terapię logopedyczną, zawierającą zestaw ćwiczeń do nauki wraz z filmami instruktażowymi poprawnego wykonania ćwiczeń. Zmontowano również zestaw pomagający w oszacowaniu poprawności wymawiania tej głoski. Przedstawione rozwiązanie daje pacjentowi możliwość codziennych ćwiczeń i samodzielnej oceny ich wykonania oraz stanowi alternatywę dla sesji logopedycznych, które w przypadku osób dorosłych są nierefundowane.

EN

The consonant „r” is difficult to pronounce and children rarely learn its pronunciation before their fifth year of age. A significant part of Polish society is not able to pronounce “r”, correctly. This disability causes a lot of problems with learning (dyslexia) and has an influence on emotional and social life (complexes). It contributes to the development of civilization diseases, like depression or neurosis. To help adults learn to pronounce “r” properly, a specially designed computer-aided therapy is proposed. It consists of instructional videos with selected mouth and tongue movement trainings, selected speaking words and sentences with “r” exercises on several levels, as well as a special electronic circuit, which was designed and soldered to real-time visual assessment of the pronunciation accuracy. This solution offers patients the possibility of daily exercises with visual analysis of pronunciation accuracy and is an alternative to speech therapy sessions, which in case of adults, are not reimbursed by health care insurance system.

20

Analiza częstotliwościowa drgań pionowych oddziaływujących na dzieci w fotelikach samochodowych

Więckowski D.

Prace Naukowe Politechniki Warszawskiej. Transport

|

2012

|

z. 87

117-129

PL

Artykuł dotyczy badań eksperymentalnych związanych z oddziaływaniem drgań pionowych na organizm dziecka siedzącego w foteliku podczas jazdy w samochodzie i porównaniu z oddziaływaniem takich drgań na człowieka dorosłego. Do badań wykorzystano manekiny: dziecka i osoby dorosłej. Manekin dziecka był posadowiony na dwóch typach fotelików: konwencjonalnym i z systemem ISOFIX. Dokonano pomiarów przyśpieszeń w różnych punktach. Przeprowadzono analizę w dziedzinie częstotliwości. Wyniki analizy zawarte są w tej pracy.

EN

Analysis of vertical vibration acting on child sitting in child car seat and comparison with vibration acting on adult measured during the same car drives has been done in the paper. Measurements were done using child and adult dummies. Dummy of child was seated in the two types of child car seat: with the ISOFIX system of fastening and typical standard fastening. Acceleration acting on dummies was measured in various selected points. Spectrum analysis is presented in the paper.