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Wyszukujesz frazę "Hydroacoustics" wg kryterium: Temat


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:
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:
Acoustic tracking dynamic phenomena in marine ecosystem
Autorzy:
Orlowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/332782.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustic tracking
marine ecosystem
hydroacoustics
Opis:
Acoustic information, collected in the form of measurements of integrated echo energiesrelated to time and 3D space has been applied at the Sea Fisheries Institute since 1981 to examine the rough statistical relationships between clupeoids distribution in the Baltic and the relevant environmental factors. In this paper it is shown that the data collected can be also applied for very detail observation of dynamic phenomena in marine ecosystem. Two differentiated case studies were selected to show new acoustic applications in specific areas of oceanographic research. In the first case spatial characteristics of fish diel vertical migration in the southern Baltic was surveyed and analysed for the period 1994-2007, against the environmental background. In the second case acoustic sounding was applied to quantify ebullition of methane from Baltic sediments. Both phenomena are strongly dependent on climatic variability. For both cases the final characteristics of the phenomenon was given in the form of video frames, expressing the processes in time. Unique method of echo-recording transformation into video frames was described and applied to analyse the process of ebullition of methane from the seabed.
Źródło:
Hydroacoustics; 2009, 12; 167-180
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustical observation of internal waves on the shelf of the Black Sea
Autorzy:
Mikryukov, A.
Popov, O.
Serebryany, A.
Powiązania:
https://bibliotekanauki.pl/articles/332808.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
acoustical observation
Black Sea
Opis:
In October, 2007, the Acoustics Institute performed complex acoustical and oceanological studies on a fixed experimental path in the Black Sea, near the Golubaya Bay. Sound signal with linear frequency modulation were used in the experiment. The processing of the experimental records consisted in computing the envelope of the correlation function of the received and transmitted signals and the time dependence of the correlation maxima. A characteristic change in arrival times of the rays is observed for the period of the income of cold near-bottom waters on the path. The quasi-harmonic variation in the arrival times of the ray groups allows one to correctly define the parameters of short-period internal waves accompanying the bore.
Źródło:
Hydroacoustics; 2009, 12; 153-158
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:
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:
An acoustic study of zooplankton diel vertical migration in the Black Sea
Autorzy:
Pezacki, P. D.
Gorska, N.
Soloviev, V.
Powiązania:
https://bibliotekanauki.pl/articles/332185.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
backscattering
ADCP
velocity of zooplankton
Opis:
Reliable, rapid and non-invasive techniques are important for the monitoring of the ecosystem of the semi-enclosed Black Sea, especially sensitive to the human impact. Hydroacoustic techniques meet these requirements. In the study, the ADCP data (volume backscattering strength and water velocities), collected in the north-east part of the Black Sea in October 2014, were used to understand some biotic and abiotic processes in the environment. The study was motivated by the fact that the used ADCP mounted on the autonomous (moving vertically) platform provided measurements with significantly higher spatial resolution that it was in the previous hydroacoustical studies of Black Sea ecosystem. The main objective of the analysis was to determine the velocity of zooplankton diel vertical migration and understand the processes responsible for the variability of the volume backscattering strength.
Źródło:
Hydroacoustics; 2017, 20; 139-148
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of non-uniform B-Splines of 2-nd order for description vertical distribution of sound speed in water
Autorzy:
Makar, A.
Powiązania:
https://bibliotekanauki.pl/articles/332798.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
B-splines
sound speed
Opis:
Modeling of the vertical distribution of the sound speed in water is useful during determination of the depth on the basis of the acoustic method, modeling refraction phenomena and determination the trajectory of the acoustic wave. For modeling 1D functions (vertical distribution of the sound speed) and 2D (surface of the sea bottom for hydrography) uniform B-Splines was used. In this paper description of uniform B-Splines and description and application of non-uniform B-Splines have been presented.
Źródło:
Hydroacoustics; 2009, 12; 133-140
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:
Bearing errors in passive sonar stationary target location
Autorzy:
Schmidt, A.
Marszal, J.
Salamon, R.
Jedel, A.
Ostrowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332830.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
bearing errors
passive sonar
hydroacoustics
Opis:
The paper presents a method for determining the coordinates of stationary targets using passive sonar bearing. It identifies the requirements sonar movements must meet to keep the incorrect determination of coordinates to a minimum. It gives the relations, which help determine coordinate errors analytically. Numerical experiments are used to demonstrate the success of the analysis.
Źródło:
Hydroacoustics; 2009, 12; 189-200
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:
Development of a coupled numerical and experimental approach to hydrodynamic noise estimation
Autorzy:
Felicjancik, J.
Gatz, M.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175566.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hydroacoustics
URN
noise estimation methods
CFD modelling
signal processing
experimental methods
model scale tests
Opis:
The hydroacoustic signatures of ship propellers can be identified experimentally through measurements of cavitation-induced pressure fluctuations and the accompanying noise distribution at model scale. These measurements have to be performed in a cavitation tunnel at the propellers operating conditions and with sufficient accuracy. In comparison, the numerical approach can be used to present a good general idea of the predicted results. Numerical methods can provide highly accurate tools for noise level and propagation prediction, as well as giving insight into the flow field and other key aspects. They are also not influenced by signal conditioning or disturbance sources present in a physical environment. So we trade scope and precision of the results for time and cost reduction. In this paper, we described both experimental and numerical methods currently in use and present advantages and limitations of the practical application of both.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2017, 138; 89-105
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of the Effective Underwater Speaker Sound Modulated by Audible Sound Frequency Range of Large Cetaceans for Avoidance with Ship Collision
Autorzy:
Yamada, H.
Kobayashi, N.
Nakashima, T.
Kato, H.
Powiązania:
https://bibliotekanauki.pl/articles/116934.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Cetaceans
Underwater Speaker (UWS)
Underwater Speaker Sound
Audible Sound Frequency Range
Hydrofoils
Hydroacoustics
Avoidance with Ship Collision
Large Cetaceans
Opis:
The underwater speaker (UWS) has been installed on high speed vessels; hydrofoils (HF) with low-noise during their cruises, to avoid sudden collisions with large cetaceans, while its performance has remained uncertain because of the problem in quality of the produced sound. Thus, we developed a sound source for the UWS by modulating the sound based on the audible range of major large cetaceans so as to increase its utilities. To investigate the audible sound frequency range of cetacean, we tried two procedures, (1) indirect-estimation from relationship between cetaceans audibility and vocalization, and (2) indirect-estimation from measurements on the cochlear basal membrane. We also synthesized the two new sound sources which we can potentially expect an avoidance with large cetaceans. Through several field experiments with deploy the new sounds we reached a tentative conclusion that the new sound was effective in terms of inducing the cetaceans' avoidance reaction and would be also expected to be applied to other low-noise vessels.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2015, 9, 2; 213-217
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł

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