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Wyszukujesz frazę "Hydroacoustics" wg kryterium: Temat


Tytuł:
Acoustic tomography of a turbulent water jet
Autorzy:
Gavrilenko, V.
Didenkulov, I.
Kustov, L.
Martyanov, A.
Nechayeva, M.
Vyugin, P.
Pronchatov-Rubtsov, N.
Powiązania:
https://bibliotekanauki.pl/articles/331748.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic tomography
turbulent water
hydroacoustics
Opis:
Measurement of parameters of flowing liquid is one of problems, which have many applications. in the present paper we describe linear and nonlinear acoustic tomography methods for reconstruction of parameters of a turbulent water jet with gas bubbles. Experiments on both techniques are described. in the linear acoustic method it was measured fluctuations of acoustic signal passed through the jet. In the nonlinear acoustic technique it was measured spectra of combination scattering signals in the jet. Experiments were done in a water tank with a submerged water jet. The results of the work demonstrate the possibility of the tomography of flowing bubble liquids.
Źródło:
Hydroacoustics; 2003, 6; 91-100
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive telecommunications modems techniques for use in underwater communication systems
Autorzy:
Budzińska, I.
Lasota, H.
Mazurek, R.
Powiązania:
https://bibliotekanauki.pl/articles/331551.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
underwater communication systems
data transmission
Opis:
Underwater channel data transmission is one of telecommunications most difficult problems. One way to optimise the transmission may be by adapting transmission techniques used in telecommunications modems. The articles presents two ITU-T standards: V.34 and G.992.1, known as ADSL. The possibilities and limitations of these techniques for underwater communication systems are discussed. The ADSI standard using the DMT modulation seems to be the best.
Źródło:
Hydroacoustics; 2003, 6; 285-292
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Autonomous hydroacoustic sound velocity profiler
Autorzy:
Jedel, A.
Marszal, J.
Ostrowski, Z.
Kilian, L.
Powiązania:
https://bibliotekanauki.pl/articles/332093.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
sound velocity profiler
Opis:
The paper presents the autonomous hydroacoustic sound velocity profiler collaborating with ordinary PC by small box included interface & battery charger. The measurement and calibration methods and block diagram of the meter are presented as well as principles of operation, data collection, selection and transmission. There are described three versions of this meter - dropped from "normal" ships, installed in the light hull of submarines and casings in the hulls of variable depth sonar antennas.
Źródło:
Hydroacoustics; 2003, 6; 261-266
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostic of intense proton beams by hydroacoustic means
Autorzy:
Albul, V. I.
Bychkov, V. B.
Gusev, K. B.
Demidov, V. S.
Demidova, E. V.
Kurchanov, A. F.
Lukijashin, V. B.
Vasilijev, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/332338.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
proton beam
Opis:
Detecting and parameters' measurement of intense beams of charged particles in accelerators' laboratories is possible to make in water volumes, using conventional measuring hydrophones with applying of new means and algorithms of hydroacoustic signals' processing. The new experimental results is given and discussed.
Źródło:
Hydroacoustics; 2003, 6; 293-294
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Principles of computing and displaying the results of detection by underwater systems as part of sound velocity measurements
Autorzy:
Raganowicz, A.
Kilian, L.
Salamon, R.
Powiązania:
https://bibliotekanauki.pl/articles/331744.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
underwater systems
hydrolocation
hydrocommunication systems
Opis:
The paper presents the upgraded system for measurements of sound velocity profiles and for computing and imaging the terms of detection in different hydrolocation and hydrocommunication systems. Three types of computations made by the system's processors are discussed. The most interesting task is to link the propagation routes and ray density with the parameters of the hydroacoustic system to obtain the desired display of the conditions to detect the signal from the background noises. Presented discussion of methodology of determining detection conditions using different forms of range equation gives a more detailed description of this task. In the next part of this paper the software's display function and necessary settings are specified and discussed. In the end two examples of computed detection conditions images (for active and passive sonar) are shown.
Źródło:
Hydroacoustics; 2003, 6; 267-274
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitivity of echo envelope fractal dimension to bottom type and bottom depth - numerical results
Autorzy:
Łubniewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332051.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic
seafloor
hydroacoustics
Opis:
The presented results are a part of those obtained within the author's latest work on application of normal incidence methods in acoustic seafloor characterisation. The work included both theoretical and experimental studies on selection of appropriate methods of seafloor echo processing and feature extraction for characterisation of the bottom type, especially, the study of the usefulness of several echo parameters like fractal dimension or statistical moments of the echo envelope. In this paper, the simulation results of the echo envelope fractal dimension dependence on bottom type and bottom depth are presented. They show that to same extent, fractal dimension of an echo may be useful for bottom identification even in a case of varying depth, however, more detailed, theoretical as well as experimental studies are needed.
Źródło:
Hydroacoustics; 2003, 6; 195-198
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical problems of the wideband sonar time-spatial filtration
Autorzy:
Janowski, T.
Kotłowski, A.
Porosińska, E.
Powiązania:
https://bibliotekanauki.pl/articles/331819.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
wideband sonar
hydroacoustics
Opis:
The paper presents the synthesis of the time-spatial matched filtration algorithm. First part specifies base for the algorithm-input data. Successively, the matched filtration for continuous junction is depicted. This leads to the canonical form of the time-spatial filter. Consecutively, the decomposition into series connection of the matched and spatial filtration is realized. The next step is the signals approximation by Fourier series due to equivalence between approximation and interpolation on uniformly distributed discrete sampIes. The equation of the spatial filtration - in frequency domain - results from this mathematical operations. Application of the Bluestein's method to solve this equation provides to the final algorithm version. Advantages of the developed algorithm are presented in conclusions.
Źródło:
Hydroacoustics; 2003, 6; 221-228
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of hydro-acoustic waves emitted from floating units during mooring tests
Autorzy:
Kozaczka, E.
Domagalski, J.
Grelowska, G.
Gloza, I.
Powiązania:
https://bibliotekanauki.pl/articles/260463.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
identification
propagation
hydroacoustics
Opis:
Measurements of hydro-acoustic noise emitted from vessels are a.o. a subject of the tests carried out in the control measurement ranges of the Navy. The measurements are performed both on anchored and floating vessels. Acoustic field of vessels is changing along with their speed changing and is associated with acoustic activity of wave sources installed in vessel’s hull (main engines, electric generating sets, reduction gears, pumps, shaft-lines, piping, ventilating ducts etc) as well as hydro-dynamic sources such as screw propellers and water flow around the hull [5, 7]. Vibration energy generated by the onboard devices is transferred through ship structural elements to water where it propagates in the form of hydro-acoustic waves of a wide frequency band.
Źródło:
Polish Maritime Research; 2007, 4; 40-46
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A review of acoustic techniques for habitat mapping
Autorzy:
Blondel, P.
Powiązania:
https://bibliotekanauki.pl/articles/331523.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic techniques
habitat mapping
hydroacoustics
Opis:
Habitat mapping has become an increasingly important application of remote sensing. Active and passive acoustic techniques have greatly improved in the last decade, and their use extends into other spheres to show their economic, legal, political and environmental benefits. This paper reviews the current status of acoustic techniques for habitat mapping. Traditional techniques include echosounders, multibeam systems and sidescan sonars. Passive techniques are also presented, along with geoacoustic inversion and acoustic daylight imaging. The developments in new techniques such as non-linear acoustics, synthetic aperture and interferometry are reviewed. Some emerging techniques are showing increasing potential for habitat mapping, and bistatic sonar, parametric SAS and 3-D chirp profiling are briefly reviewed. Leading international programmes are now making use of these techniques, most often in combination, and their results inform the recommendations for future uses and desired technological developments.
Źródło:
Hydroacoustics; 2008, 11; 29-38
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active control of a submerged circular plate
Autorzy:
Wiciak, J.
Powiązania:
https://bibliotekanauki.pl/articles/331655.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
shipboard noise
hydroacoustics
ICSV
Opis:
Structure vibrations and structure borne sound may be reduced by passive and active isolation, by passive and active vibration and sound absorbers or by active control. The experiment presented in this paper is a part of an ongoing research project connected with the structural acoustic control in fluid loading structures. The paper presents the opportunity of active control of vibrations and sound through the application of a circular plate containing distributed piezoelectric actuators and sensors. The plate is supported on the edges in a rectangular enclosure and is loaded on one side by heavy fluid (sweet water) and on the other side has contact with a gaseous medium (air). Piezoelectric elements are arranged in sets, each containing four elements located on two concentric circles with different radii.
Źródło:
Hydroacoustics; 2008, 11; 441-448
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compression algorithms for multibeam sonar records
Autorzy:
Chybicki, A.
Moszyński, M.
Poćwiardowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/331502.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
compression algorithms
sonar records
hydroacoustics
Opis:
Operational requirements of multibeam sonar systems result in very large volumes of datasets stored on local hard drives of operator's station. In this context, the process of archiving acquired data becomes a crucial problem. The paper investigates various lossy and lossless compression methods that can be applied to multibeam sonar data to reduce the size of acquired files without loosing relevant information. The specific character of MBS data allows applying various signal, image and video compression methods to achieve better results than when using standard compression tools. Various techniques of reordering the data were analyzed to achieve best possible compression ratio.
Źródło:
Hydroacoustics; 2008, 11; 55-62
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Contribution of the IMS global network of hydroacoustic stations for monitoring the CTBT
Autorzy:
Bitnner, P.
Jonathan, E.
Villarroel, M.
Powiązania:
https://bibliotekanauki.pl/articles/331513.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
CTBT
IMS
hydroacoustics
Opis:
The International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) Preparatory Commission, in Vienna operates a global network of 321 monitoring stations and 16 radionuclide laboratories that monitors the earth for evidence of nuclear explosions within the atmosphere, underwater and underground. The IMS uses a network of four verification technologies: seismic, hydroacoustic, infrasound and radionuclide. All the data recorded by the IMS network are transmitted to the International Data Centre (IDC) of the CTBTO in Vienna. The data are then received, processed, resulting data and products distributed and archived by the IDC. This study will give an overview of the contribution of the IMS hydroacoustic network and will highlight that for areas not well covered with the seismic network this part of the IMS can be very valuable for detecting events, improving the location obtained from the seismic network and providing information about the nature of sources.
Źródło:
Hydroacoustics; 2008, 11; 19-26
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kohonen networks as ships classifier
Autorzy:
Żak, A.
Powiązania:
https://bibliotekanauki.pl/articles/331686.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
Kohonen networks
hydroacoustics
ships classifier
Opis:
The paper presents the technique of artifficial neural networks used as classifier of hydroacoustic signatures generated by moving ship. In the paper firstly the method of feature extraction from hydracoustic signatures using calculation of Mel-Frequency Cepstral Coefficients was discussed. Next the mathod of feature matching using for purpose of object classification basing on hydroacoustic signatures was described. The technique of artificial neural networks especially Kohonen networks which belongs to group of self organizing networks where chosen to solve the research problem of classification. the choice was caused by some advantages of mentioned kind of neural networks for example they are ideal for finding relationships amongst complex sets of data, they have possibility to self expand the set answers for new input vectors. To check the correctness of classifier work the research in which the number of right classification for presented and not presented before hydroacoustic signatures were made. some results of research were presented on this paper.
Źródło:
Hydroacoustics; 2008, 11; 467-476
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł

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