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Wyświetlanie 1-7 z 7
Tytuł:
Wave Intensity Distributions in Complex Structures
Autorzy:
Tanner, G.
Chappell, D.
Maksimov, D.
Powiązania:
https://bibliotekanauki.pl/articles/1492500.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.40.Dx
43.20.Dk
43.20.Rz
Opis:
The vibro-acoustic response of mechanical structures can in general be well approximated in terms of linear wave equations. Standard numerical solution methods comprise the finite or boundary element method in the low frequency regime and statistical energy analysis in the high-frequency limit. Major computational challenges are posed by the so-called mid-frequency problem - that is, composite structures where the local wavelength may vary by orders of magnitude across the components. Recently, a new approach towards determining the distribution of mechanical and acoustic wave energy in complex built-up structures improving on standard statistical energy analysis has been proposed. The technique interpolates between statistical energy analysis and ray tracing containing both these methods as limiting cases. The method has its origin in studying solutions of wave equation with an underlying chaotic ray-dynamics - often referred to as wave chaos. Within the new theory - dynamical energy analysis - statistical energy analysis is identified as a low resolution ray tracing algorithm and typical statistical energy analysis assumptions can be quantified in terms of the properties of the ray dynamics. We have furthermore developed a hybrid statistical energy analysis/finite element method based on random wave model assumptions for the short-wavelength components. This makes it possible to tackle mid-frequency problems under certain constraints on the geometry of the structure. Dynamical energy analysis and statistical energy analysis/finite element method calculations for a range of multi-component model systems will be presented. The results are compared with both statistical energy analysis results and finite element method as well as boundary element method calculations. Dynamical energy analysis emerges as a numerically efficient method for calculating mean wave intensities with a high degree of spatial resolution and capturing long range correlations in the ray dynamics.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-172-A-177
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Sound Source Directivity on Acoustics Parameters Distribution in Kraków Opera House
Autorzy:
Gołaś, A.
Suder-Dębska, K.
Filipek, R.
Powiązania:
https://bibliotekanauki.pl/articles/1537421.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.55.Ka
43.20.Dk
43.40.Rj
Opis:
Determining of Kraków Opera House's basic acoustics parameters by using numerical simulations is presented in the paper. Parameters have been obtained by using numerical simulation methods. Sound sources have been created by means of FEA, however acoustic field distributions have been analysed by geometrical methods. Apart from the room parameters definition, it is necessary to determine sound source parameters like acoustic power level and directivity pattern. In the simplest case, the sound source can be assumed as omni-directional point source. However it does not reflect most real-live sources precisely. When the literature and databases do not contain any information about the sound source directivity pattern, it can be obtained numerically using FEA. First, the sound source model is created, and then results from its spherical boundary are used to define the source in a program based on geometrical methods. Here have been analysed several distributions of acoustic parameters like: Direct Energy, Sound Pressure Level (SPL), Clarity index (C80) etc. The results indicate that influence of sound source directivity on acoustics parameters changes is essential.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 62-65
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability Influence of Input Parameters οn Result of Room Acoustic Calculation
Autorzy:
Mleczko, D.
Wszołek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1537528.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.20.Dk
43.50.Jh
43.55.Ka
Opis:
For a long time there is a need in industry of acoustical modeling of rooms. Modeling is necessary for new production room design, the exchange of existing machinery, modernization or expansion of production rooms, changes in production profile or acoustical room adaptation for acoustical work conditions improvement. in such cases modeling quality is essential and thanks to uncertainty analysis it is possible to quantitatively estimate the effect that input parameters value variation has on model behavior. The article presents general rules for sound pressure level prediction uncertainty calculation in a room. By partial uncertainty calculation analysis of input parameters influence on uncertainty prediction an effort was taken to find parameters with biggest influence on the prediction process. As an example an industrial production room is presented which was modeled to predict noise level on a work stands after it was expanded.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 128-130
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Changes in Position of Sound Source and Microphone on Acoustic Measurements in Small Rooms. A Case Study
Autorzy:
Mleczko, D.
Wszołek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1359909.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.20.Dk
43.50.Jh
43.55.Ka
43.58 Ta
43.55.-n
43.55.+p
Opis:
Results of computer simulations and measurements in real interior for varying location of sound source and microphone are shown in the paper. A small room with a volume of 47 $m^3$ was used for this purpose. The objective of measurements and calculations was to determine the sound pressure level and other parameters derived from the room impulse response ($T_{30}$, EDT, $C_{80}$, STI) followed by the sensitivity analysis of those parameters to changing the location and orientation of the sound source and the receiver. In order to determine these parameters, the room impulse response was measured using MLS method. Experimental studies have been used to verify the acoustic room model built with use of enhanced radial method algorithms and its sensitivity. That allowed complementary and extended simulation studies on the room acoustic characteristics and finally determination of sensitivity of output parameters to changes of location and orientation of the measurement channel elements.
Źródło:
Acta Physica Polonica A; 2014, 125, 4A; A-131-A-134
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of the Impulse Response of the Transmission Path in a Selected Area of the Sound Field
Autorzy:
Czajka, I.
Suder-Dębska, K.
Gołaś, A.
Powiązania:
https://bibliotekanauki.pl/articles/1400094.pdf
Data publikacji:
2013-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.55.Ka
43.20.Dk
43.40.Rj
43.55.-n
43.55.+p
43.55.Jz
43.58.Ta
Opis:
Providing appropriate sound field parameters in the listening area is very important. It often determines the possibilities of being able to use a facility. Assuming that the sound system is a linear object, it can be described by the impulse response. Unfortunately, it is not possible to designate a single impulse response for such a facility because it is a continuous system. Thus each path between the transmitter and the receiver has its own impulse response. Therefore, the authors have made an attempt to synthesize the impulse response for transmitter-receiver paths with suitable parameters of the sound field in the neighbourhood of the receivers. A technical implementation of the presented synthesis will take place through introduction of additional sources. An experimental determination of the impulse response is relatively simple. The transient response can be numerically determined by using, for example, the finite element method or the boundary element method. Unfortunately, determining the impulse response through simulation of, e.g., planned objects, is much more difficult due to the high computational cost and the lack of precise data on the properties of the materials. For this reason, the authors used an energetic analogue of the impulse response, the echogram.
Źródło:
Acta Physica Polonica A; 2013, 123, 6; 1072-1077
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of EGNOS-Augmented GPS Receiver Positioning Accuracy
Autorzy:
Skorkowski, A.
Topór-Kamiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/1417964.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.10.Pr
89.20.Hh
06.20.Dk
07.05.Hd
Opis:
This study presents the operation basis of GPS global positioning system and augmentation systems used to increase positioning accuracy. Furthermore, selected measurement results for an EGNOS-augmented GPS receiver positioning are included along with an analysis of GIS measurements accuracy, performed using differential corrections. This analysis takes into consideration the impact of the number of measurement series and satellite constellation on the accuracy of positioning achieved in praxis using the EGNOS system.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 821-824
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected Methods of Measuring the Delay in Data Transmission Systems with Wireless Network Interfaces
Autorzy:
Topor-Kaminski, T.
Żurkowski, R.
Grygiel, M.
Powiązania:
https://bibliotekanauki.pl/articles/1493274.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.10.Pr
89.20.Hh
06.20.-f
06.20.Dk
07.05.Hd
Opis:
The article presents the concept of creating model of delays occurring in telecommunication system taking into account all sources of delays generated during data transmission between the source and destination nodes. Proposed model takes into account the existence of intermediary network devices that play a significant role in the general delay budget. The paper presents two measurement systems used to measure delays in 802.11 g based wireless networks and ones using ZigBee standard. Both systems were built based on the authors' concepts of hardware and software allowing measurement of delays by using additional connection for the synchronization of internal clocks. Described measurement systems selected amount of experiments was performed for varied network structures.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 748-754
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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