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Tytuł:
Monitoring of ocean current perturbations using acoustic phase variations
Autorzy:
Zieliński, A.
Butowski, M.
Kraeutner, P.
Powiązania:
https://bibliotekanauki.pl/articles/332840.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
ocean current perturbations
acoustics phase variations
hydroacoustics
Opis:
In this paper, we review an acoustic method for measuring both average ocean current speed and sound speed along an acoustic path. The method requires two or more stations on the sea floor, synchronized through a connecting underwater electric cable, that can transmit and receive an acoustic signal and The method is based on reciprocal acoustic transmissions to determine time of flight in both the forward and reverse directions. A specific implementation of this method is proposed. We also consider a novel method for monitoring ocean current perturbations through acoustic phase measurements. In simplest form, a continuous sinusoidal signal is transmitted from one station to a second station. Any variations in ocean current speed will introduce a phase shift in the received signal proportional to the time derivative of the current speed. This effect has been demonstrated through ultrasonic in-air experiments. Finally, the two methods are combined into a single system that continuously measures small-scale ocean current velocity changes.
Źródło:
Hydroacoustics; 2009, 12; 237-248
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydroacoustics waves direct-of-arrival estimation using music algorithm - simulations results
Autorzy:
Żak, A.
Powiązania:
https://bibliotekanauki.pl/articles/332842.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
music algorithm
hydroacoustics waves
hydroacoustics
Opis:
Paper presents simulations results of hydroacoustics waves' direction-of-arrival estimation using MUSIC algorithm. Firstly, the research problem is formulated by general description of studied case and release of simplifying assumption. Next the used to direct-of-arrival estimation MUSIC algorithm was discussed. The mathematical formulations, algorithm of calculation and some computational issues were presented. At the end of the paper the simulations results of estimation of direction-of-arrival using MUSIC algorithm for hypothetical situation were presented.
Źródło:
Hydroacoustics; 2009, 12; 249-256
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
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
Tytuł:
SLAM – Based Approach to Dynamic Ship Positioning
Autorzy:
Wróbel, K. A.
Powiązania:
https://bibliotekanauki.pl/articles/116689.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Dynamic Ship Positioning
Simultaneous Localization and Mapping (SLAM)
Dynamic Positioning (DP)
Reference System
SLAM Method
SLAM Post-Processing
Doppler Velocity Log (DVL)
Hydroacoustics
Opis:
Dynamically positioned vessels, used by offshore industry, use not only satellite navigation but also different positioning systems, often referred to as ‘reference’ systems. Most of them use multiple technical devices located outside the vessel which creates some problems with their accessibility and performance. In this paper, a basic concept of reference system independent from any external device is presented, basing on hydroacoustics and Simultaneous Localization and Mapping (SLAM) method. Theoretical analysis of its operability is also performed.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2014, 8, 1; 21-25
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
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:
Sound and vibration analysis for 70 m supply vessel in aspect of underwater noise reduction
Autorzy:
Weryk, M.
Kusmirek-Ochrymiuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/331657.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
underwater noise reduction
hydroacoustics
vessel
Opis:
The underwater noise and on-board noise measurement analysis, for 70 m supply ship, are presented in the paper, as well as the noise data for main machinery installed on-board. The results were completed by vibration measurements, then comparative analysis and identification of main sources of sound were executed. The main aim for this project was to analyse noise propagation and identify main noise excitation components resulting in underwater noise propagation. Some preliminary proposals of underwater noise reduction are put forward in the paper.
Źródło:
Hydroacoustics; 2008, 11; 431-440
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low- and high-frequency elastic scattering analysis of fluid-filled, flat-endcapped cylindrical shells proud on a sandy seabed
Autorzy:
Tesei, A.
Groen, J.
Powiązania:
https://bibliotekanauki.pl/articles/331639.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
sandy seabed
at-sea scattering data
hydroacoustics
Opis:
This work presents the analysis of at-sea scattering data by a man-made target which supports the excitation of strong structural waves or resonances, not only at low but even at high frequency (ka>100). The object is a water-filled, flat-endcapped, 2m-long, steel cylindrical shell, measured both at low frequency (2-10 kHz) and at high frequency (120 kHz), where different elastic phenomena are supported and identified. In particular, in the high-frequency sonar images obtained with an AUV-mounted synthetic aperture sonar, significant elastic effects clearly appear, which are interpreted as echoes of a shear wave travelling axially along the cylindrical shell. For interpretation of sonar images it is crucial to understand and predict these supplementary scattering mechanisms.
Źródło:
Hydroacoustics; 2008, 11; 388-400
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examination of the co-operation between echosounder and motion sensor during sea trials
Autorzy:
Szymczak, W.
Buszman, K.
Powiązania:
https://bibliotekanauki.pl/articles/332836.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
echosounders
sea trials
Opis:
Sea trials with parametric echosounder SES-2000 Compact needs precise information about sounded area of the seafloor. Because of narrow beam both in horizontal and vertical surface each change of antenna position have high influence for results and analyze of measured data. Vessel has to be equipped with a special device, such as multibeam echosounder, to obtain more information about seafloor sounding which is an addition for basic measurements units. Information about bottom topography, from where sounding pulse comes, may give many useful data necessary to correct analyze by echosounder user. There are also parameters such as roll, pitch and heave, which have to be complied. These variables have an influence for shape and echo level. The last parameter analyzed in this article is a difference between vessels heading and bearing. This information comes from heading sensor and GPS receiver.
Źródło:
Hydroacoustics; 2009, 12; 217-226
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation and measurements of resonance scattering on the gas filled polymer microspheres
Autorzy:
Secomski, W.
Klimonda, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332832.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
polymer microspheres
gas filled
hydroacoustics
Opis:
The gas filled polymer spheres are used either as an ultrasonic contrast agents or controlled drug delivery microcapsules. The power spectrum of the ultrasonic backscattered signal was calculated from the resonance scattering theory for the gas bubbles surrounded by elastic shield. The size distribution of the measured microspheres was included in the calculations. In experiment, the backscattered power spectrum of measured sample was recorded by Siemens Antares ultrasonic scanner. Radio frequency (RF) data was recorded for 2.5 - 6.7 MHz transmitted ultrasonic frequencies. The backscattered spectra were calculated by Matlab software and subtracted from the transmitter spectrum, recorded as an echo from the perfect reflector. The particle size in measured sample was 12 µm mean š 8 µm sd. The resonance frequency, measured under the microscope, was 0.60 MHz for 45 µm diameter microsphere which corresponds to 2.25 MHz for 12 µm sphere. The sample volume was 10cm? and the mean quantity of scatterers was 6ź103/cm?. In conclusion, measured spectra matched those calculated from theory. The use of ultrasonic scanner with RF data output and the high sensitivity, wide bandwidth ultrasonic transducer allows to measure backscattered signal from the very small quantity of resonance scatterers with satisfactory results at 40 dB signal to noise ratio.
Źródło:
Hydroacoustics; 2009, 12; 201-208
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:
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:
Zastosowanie metod akustycznych i magnetycznych w poszukiwaniu obiektów archeologicznych na przykładzie jeziora Lednica
The use of acoustic and magnetic methods in the search for archaeological objects through the example of Lednica lake
Autorzy:
Pydyn, Andrzej
Hac, Benedykt
Popek, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/532028.pdf
Data publikacji:
2019
Wydawca:
Muzeum Pierwszych Piastów na Lednicy
Tematy:
archeologia podwodna
geofizyka
magnetometr
hydroakustyka
profilograf osadów dennych
sonda wielowiązkowa
średniowiecze
most
wyspa Ledniczka
jezioro Lednica
underwater archaeology
geophysics
magnetometer
hydroacoustics
subbotto
profilers
multibeam probe
Middle Ages
a bridge
Ledniczka island
Lednica lake
Opis:
Noninvasive surveys and prospections are a new dynamic trend in contemporary archaeology. They represent a trend of multidisciplinary analyses of cultural heritage. Due to limited access to technology, these methods are still not widely used in underwater archaeology, in particular in inland reservoirs. For this reason a team from the Department of Underwater Archaeology of the Institute of Archaeology at Nicolaus Copernicus University in Toruń in cooperation with the Maritime Institute in Gdańsk, the Museum of the First Piasts at Lednica and the Scientific Association of Polish Archaeologists (Warsaw branch), planned and completed a project Kolebka Piastów — archeologiczne prospekcje podwodne w rejonie jeziora Lednickiego in 2017. The project was financed by the Ministry of Culture and National Heritage under the following programme: Cultural heritage, priority: The protection of archaeological monuments. In the course of the project a multibeam probe, a subbottom profiler and a magnetometer were used to conduct surveys. If the conditions and assumptions of the project allowed, a direct underwater verification was conducted. Due to multibeam sonar it is possible to obtain a reliable spatial picture of a lake bottom in high resolution, e.g. 100 or more measurement points for each m2 of the bottom, which enables one to conduct a detailed overview of a surface of the research area and objects lying on it. This method turned out to be the most effective during verification and resulted in the localization of a new medieval bridge in Lednica lake. Using a subbottom sediment profiler is at the moment the only noninvasive method of searching for non-magnetic objects sunk into the bottom. After applying it on a recognized object, such as the Poznań bridge, and after receiving the positive results, it may be assumed — with high probability — that this technology will succeed in the search for other wooden archaeological structures located in subbottom sediments. Magnetometric measurements are the next technology which was used in the researched reservoir. They are indispensable when noninvasive large scale searches of metal objects with magnetic signatures are conducted e.g. the objects made of iron or steel. In the area of Lednica lake several objects with a magnetic signature were localized. In the course of research in Lednica, three types of noninvasive prospections were applied: hydroacoustics (a multibeam probe), seismology (subbottom sediment profiler) and magnetics (Caesium magnetometer). Each of these methods helps to localize other objects and gives very interesting results; however, only after all three have been used is it possible to obtain a precise picture of the bottom of the lake together with anomalies, which to a large extent can have anthropogenic origins. It seems that the future of underwater archaeology is closely related to the described noninvasive surveys. Unfortunately it will be more difficult to achieve in shallow inland reservoirs than in sea waters, where these technologies have already been introduced for some time now.
Źródło:
Studia Lednickie; 2019, 18; 179-193
0860-7893
2353-7906
Pojawia się w:
Studia Lednickie
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:
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
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