Katalog Czasopism

• Seafloor relief reconstruction from side scan sonar data

  Publikacja

  • Z. Łubniewski
  • K. Bikonis

  - HYDROACOUSTICS - Rok 2007

  Side scan sonar is one of the most widely used imaging systems in the underwater environment. It is relatively cheap and easy to deploy, in comparison with more powerful sensors. Although side scan sonar does not provide seafloor bathymetry directly, its records are directly related to seafloor images. In the paper, the method for 3D seafloor relief reconstruction from side scan sonar data is presented. The method is based on the...

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• On statistical linear inverse problems in fishery acoustic

  Publikacja

  • M. Moszyński

  - HYDROACOUSTICS - Rok 2007

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• Application of Maximum-Length Sequences to impulse response measurement of hydroacoustic communications systems

  Publikacja

  • R. Mazurek
  • H. Lasota

  - HYDROACOUSTICS - Rok 2007

  There is a growing interest in digital transmission of telemetry data on ultrasonic waves. The dependence of signal attenuation on squared frequency, specific to the hy-droacoustic systems, induces problems that do not exist in monochromatic, narrowband radio communications systems. For adapting the transmission parameters to current propagation conditions, a precise knowledge of instantaneous changes of channel performances is...

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• development of an open source software to transform acoustic data for classification of benthic habitat

  Publikacja

  • N. Sanchez-Carnero
  • M. Moszyński

  - HYDROACOUSTICS - Rok 2007

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• High accuracy hydroacoustic system to study codend model parameters

  Publikacja

  • J. Marszal
  • J. Schmidt
  • A. Schmidt
  • A. Jedel
  • W. Leśniak
  • Z. Wojan
  • K. Zachariasz

  - HYDROACOUSTICS - Rok 2008

  Ważnym zadaniem projektantów narzędzi połowowych jest stworzenie efektywnych narzędzi połowowych działających selektywnie poprzez optymalizacje ich geometrii. Hydroakustyczny system pomiaru geometrii modeli worków dorszowych opisany w artykule został zaprojektowany dla opracowania konstrukcji worka dorszowego na potrzeby rybołówstwa na Morzu Bałtyckim.System składa się z 10 par przetworników ultradźwiękowych, mikroprocesorowego...

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• Modeling of the finite amplitude plane wave propagation in non-dissipative medium

  Publikacja

  • A. Baranowska

  - HYDROACOUSTICS - Rok 2008

  Praca prezentuje wyniki analizy teoretycznej zagadnienia propagacji fali płaskiej o skończonej amplitudzie w ośrodku wodnym bez dyssypacji. Przedstawiono model matematyczny i przykładowe wyniki obliczeń numerycznych. Model matematyczny zbudowano w oparciu o jednowymiarowe równania mechaniki płynów. Do rozwiązania zagadnienia zastosowano metodę różnic skończonych. Analizowano zmiany ciśnienia i zmiany widma. Badano zbieżność i dokładność...

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• Acoustic signal processing in passive sonar system with towed array

  Publikacja

  • M. Rudnicki
  • A. Raganowicz
  • J. Schmidt

  - HYDROACOUSTICS - Rok 2008

  W referacie opisano przetwarzanie sygnałów akustycznych w pasywnym systemie hydrolokacyjnym. W pojęciu ''przetwarzanie sygnałów akustycznych'' mieszczą się wszelkie operacje wykonywane na sygnałach analogowych tj. wzmacnianie, filtracja i próbkowanie, jak również operacje na sygnałach cyfrowych uzyskanych w procesie próbkowania. Do operacji cyfrowych wykonywanych w systemie zalicza się synchronizację, konwersję, sortowanie, wytwarzanie...

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• Compression algorithms for multibeam sonar records

  Publikacja

  • A. Chybicki
  • M. Moszyński
  • P. Pocwiardowski

  - HYDROACOUSTICS - Rok 2008

  Jednym z najczęściej używanych urządzeń służących do szeroko rozumianego telemonitoringu morskiego są sonary wielowiązkowe (ang. Multibeam systems MBS). Ich wysoka wydajność w tworzeniu informacji o obiektach znajdujących się pod wodą skutkuje w dużych ilościach danych pozyskiwanych podczas rejsów badawczych i pomiarowych. W tym kontekście, proces przechowywania i zarządzania takim magazynem danych staje się istotnym problemem...

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• Modelling of acoustic backscattering by southern Baltic herring

  Publikacja

  • J. Idczak
  • N. Gorska

  - HYDROACOUSTICS - Rok 2016

  Assessment of Baltic herring abundance can be carried out using acoustic techniques. Analysis of the relationship between the Baltic herring individual target strength, TS, and the total fish length, L, important for the acoustic assessment, showed the relationship to be dependent on the location of the study area. This finding motivated a detailed analysis of the relationship for the herring occurring in the southern Baltic...

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• Study of swimbladder morphometry of Baltic herring and sprat (development of measurement methodology)

  Publikacja

  • J. Idczak
  • N. Gorska
  • B. Arciszewski

  - HYDROACOUSTICS - Rok 2011

  Effective management of Baltic clupeids, which are valuable commercially and ecologically,requires the biomass control. The acoustical techniques are recognized as effective in fishstock assessment. The study of Baltic herring and sprat individual backscatteringcharacteristics is required for the accurate biomass estimation using acoustical techniques.The previous measurements demonstrated significant...

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• On the acoustic backscattering by Baltic herring and sprat

  Publikacja

  • N. Gorska
  • J. Idczak

  - HYDROACOUSTICS - Rok 2010

  Accurate abundance estimate of Baltic clupeids, herring and sprat, is required for theirsustainable exploitation. The understanding the sound backscattering of individual fish isimportant for employing the acoustical techniques, which are widely used in the estimation.The previous studies demonstrated that the improvement of the understanding is critical forthe Baltic herring and sprat. It was the main...

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• Backscattering properties of southern Baltic herring

  Publikacja

  • J. Idczak
  • N. Kniaź-Kubacka

  - HYDROACOUSTICS - Rok 2012

  Reliable TS(L) relationship is required to improve acoustic algorithms of abundanceestimation of Baltic herring. The relationships, empirically obtained in different parts of theBaltic Sea, produce up to 8 dB – difference in the herring TS. In order to develop an accurateTS(L) relationship, it is important to analyze factors controlling the TS variability. Thepossible impact of the regional difference...

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• Chirp-rate estimation of FM signals in the time-frequency domain

  Publikacja

  • K. Czarnecki

  - HYDROACOUSTICS - Rok 2014

  Novel dynamic representations of a complex signal in the time-frequency domain including: a channelized instantaneous complex frequency (CICF), a complex local group delay (CLGD) and a channelized instantaneous chirp-rate (CICR) are introduced. The proposed approach is based on the use of the gradient of the short-time Fourier transform complex phase. An interpretation of the newly-introduced distributions especially of the CICR...

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• RADIATION OF HIGH INTENSITY SOUND BY CIRCULAR DISC BY MEANS OF THE NUMERICAL METHOD

  Publikacja

  • G. Grelowska
  • E. Kozaczka

  - HYDROACOUSTICS - Rok 2014

  The main goal of this paper is to find sound pressure distribution radiated by the circular piezoelectric disc that vibrates with the finite amplitude. There has been presented the pressure distribution close to the radiating surface. Also it is shown the sound pressure distribution in the 3D form. The mathematic modeling was carried out on the base of the nonlinear acoustic equation with the proper boundary condition. The axial...

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• INVESTIGATION OF BOTTOM SEDIMENT STRATIFICATION

  Publikacja

  • G. Grelowska
  • E. Kozaczka

  - HYDROACOUSTICS - Rok 2014

  The main goal of this paper is to find a method to assess remotely the type of sediments on the basis of the signal received using the parametric echosounder. The images of the sea bottom sediments taken by a parametric echosounder show the fine structure of the upper layer of the bottom sediments. The depth of penetration depends on the type of sediment, in fact on the attenuation of acoustic wave. In the paper the method of distinguishing...

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• Ultrawideband transmission in physical channels: a broadband interference view

  Publikacja

  • H. Lasota
  • I. Kochańska
  • R. Mazurek

  - HYDROACOUSTICS - Rok 2014

  The superposition of multipath components (MPC) of an emitted wave, formed by reflections from limiting surfaces and obstacles in the propagation area, strongly affects communication signals. In the case of modern wideband systems, the effect should be seen as a broadband counterpart of classical interference which is the cause of fading in narrowband systems. This paper shows that in wideband communications, the time- and frequency-domain...

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• The Doppler effect in a bistatic system for determining the position of moving targets

  Publikacja

  • Z. Ostrowski

  - HYDROACOUSTICS - Rok 2014

  The article presents the theoretical analysis and the results of numerical calculations of the Doppler effect it occurs in a system designed to determine the position and speed of a moving target. The transmitter is the source of the signal and it emits a sinusoidal, acoustic and continuous wave. Signal reflected off a moving target is received by four hydrophones. Based on the signals, four Doppler shifts are determined and inserted...

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• Reliable underwater communication system for shallow coastal waters

  Publikacja

  • J. Schmidt

  - HYDROACOUSTICS - Rok 2014

  This paper presents a reliable and robust low data rate spread spectrum approach which is implemented in the acoustic underwater communication system for shallow coastal waters. It shows operation assumptions of spread spectrum techniques based on the wellknown Shannon equation. It describes two methods of spread spectrum: frequency hopping spread spectrum and direct sequence spread spectrum; their block diagram and their characteristics...

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• The hydrodynamic pressure field of the ship Zodiak, measurements and calculations

  Publikacja

  • J. Bielański

  - HYDROACOUSTICS - Rok 2014

  The article presents the results of measurements of the slowly changing hydrodynamic pressure field HPF generated by the movement of the ship, Zodiak, in the Bay of Gdansk. The measurement results have been obtained in the framework of the program of the work in Siramis, under the auspices of the European Defence Administration of the EU, by the research team of the Naval Academy in Gdynia. The measurement results were compared with...

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• Reconstruction Methods for 3D Underwater Objects Using Point Cloud Data

  Publikacja

  • M. Kulawiak
  • Z. Łubniewski

  - HYDROACOUSTICS - Rok 2015

  Existing methods for visualizing underwater objects in three dimensions are usually based on displaying the imaged objects either as unorganised point sets or in the form of edges connecting the points in a trivial way. To allow the researcher to recognise more details and characteristic features of an investigated object, the visualization quality may be improved by transforming the unordered point clouds into higher order structures....

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