Rok 2009

• Weakly nonlinear dynamics of short acoustic waves in exponentially stratified gas

  Publikacja

  • A. Perelomova

  - Archives of Acoustics - Rok 2009

  Rozpatruje się dynamika krótkich (w porównywaniu z charakterystyczną skalą zmiany gęstości gazu atmosferycznego) fal akustycznych. Wyprowadzone nowe równanie ewolucyjne, które uwzględnia dyspersję i nieliniowy charakter propagacji tych fal. Porównuje sie liniowa i nieliniowa dynamika. Ilustracje propagacji, numeryczne wyliczione na podstawie nowych wzorów, są przedstawione. Indexed and abstracted (from vol. 32(1) 2007) in Science...

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Rok 2006

• Vowel recognition based on acoustic and visual features

  Publikacja

  • P. Dalka
  • B. Kostek
  • A. Czyżewski

  - Archives of Acoustics - Rok 2006

  W artykule zaprezentowano metodę, która może ułatwić naukę mowy dla osób z wadami słuchu. Opracowany system rozpoznawania samogłosek wykorzystuje łączną analizę parametrów akustycznych i wizualnych sygnału mowy. Parametry akustyczne bazują na współczynnikach mel-cepstralnych. Do wyznaczenia parametrów wizualnych z kształtu i ruchu ust zastosowano Active Shape Models. Jako klasyfikator użyto sztuczną sieć neuronową. Działanie systemu...

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• Visualisation forms in passive sonar with towed array

  Publikacja

  • A. Raganowicz
  • L. Kilian
  • J. Marszal
  • Z. Ostrowski
  • A. Schmidt

  - Archives of Acoustics - Rok 2006

  Artykuł dotyczy organizacji zobrazowań na monitorach modernizowanego w KSEM sonaru pasywnego z długą, holowaną za rufą okrętu, anteną akustyczną. We wprowadzeniu opisano strukturę takiego sonaru oraz sposób pozyskiwania i charakter odbieranych sygnałów jako podstawę organizowania zobrazowań efektów nasłuchu. Dalej opisano inne czynniki wpływające na organizację obrazów na monitorach sonaru tzn. zadania operatorów, organizację i...

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• Sound velocity and parameter of nonlinearity of a ternary mixture consisting of water, vapour and dry air

  Publikacja

  • A. Perelomova

  - Archives of Acoustics - Rok 2006

  Rozpatruje się własności akustyczne mieszanki trójskładnikowej zawierającej wodę, parę wodną i suche powietrze. Dokładne obliczenia pozwoliły na wyprowadzenie prędkości dźwięku i parametru nieliniowości jako funkcji koncentracji pary wodnej i powietrza przy zadanych warunkach równowagowych. Rozpatrywane są dwa typy mieszanin. Przedstawiono wzory ogólne oraz symulacje numeryczne.

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Rok 2017

• Voiceless Stop Consonant Modelling and Synthesis Framework Based on MISO Dynamic System

  Publikacja

  • G. Korvel
  • B. Kostek

  - Archives of Acoustics - Rok 2017

  A voiceless stop consonant phoneme modelling and synthesis framework based on a phoneme modelling in low-frequency range and high-frequency range separately is proposed. The phoneme signal is decomposed into the sums of simpler basic components and described as the output of a linear multiple-input and single-output (MISO) system. The impulse response of each channel is a third order quasi-polynomial. Using this framework, the...

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• Subjective and Objective Comparative Study of DAB+ Broadcast System

  Publikacja

  • P. Falkowski-Gilski
  • J. Stefański

  - Archives of Acoustics - Rok 2017

  Broadcasting services seek to optimize their use of bandwidth in order to maximize user’s quality of experience. They aim to transmit high-quality digital speech and music signals at the lowest bitrate. They intend to offer the best quality under available conditions. Due to bandwidth limitations, audio quality is in conflict with the number of transmitted radio programs. This paper analyzes whether the quality of real-time digital...

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• Standing Waves in One-Dimensional Resonator Contaning an Ideal Isothermal Gas Affected by the Constant Mass Force

  Publikacja

  • A. Perelomova

  - Archives of Acoustics - Rok 2017

  The study is devoted to standing acoustic waves in one-dimensional planar resonator which containing an ideal gas. A gas is affected by the constant mass force. Two types of physically justified boundary conditions are considered: zero velocity or zero excess pressure at both boundaries. The variety of nodal and antinodal points is determined. The conclusion is that the nodes of pressure and antinodes of velocity do not longer...

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Rok 2014

• Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter

  Publikacja

  • M. Blok
  • P. Drózda

  - Archives of Acoustics - Rok 2014

  In this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely...

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• Underwater Acoustic Imaging of the Sea

  Publikacja

  • G. Grelowska
  • E. Kozaczka

  - Archives of Acoustics - Rok 2014

  Acoustic waves are a carrier of information mainly in environments where the use of other types of waves, for example electromagnetic waves, is limited. The term acoustical imaging is widely used in the ultrasonic engineering to imaging areas in which the acoustic waves propagate. In particular, ultrasound is widely used in the visualization of human organs - ultrasonography (Nowicki, 2010). Expanding the concept, acoustical imaging...

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• Standing Waves and Acoustic Heating (or Cooling) in Resonators Filled with Chemically Reacting Gas

  Publikacja

  • A. Perelomova
  • W. Pelc-Garska

  - Archives of Acoustics - Rok 2014

  Standing waves and acoustic heating in a one-dimensional resonator filled with chemically reacting gas, is the subject of investigation. The chemical reaction of A ! B type, which takes place in a gas, may be reversible or not. Governing equations for the sound and entropy mode which is generated in the field of sound are derived by use of a special mathematical method. Under some conditions, sound waves propagating in opposite...

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Rok 2013

• UNDERWATER NOISE GENERATED BY A SMALL SHIP IN THE SHALLOW SEA

  Publikacja

  • G. Grelowska
  • E. Kozaczka
  • S. Kozaczka

  - Archives of Acoustics - Rok 2013

  Study of the sea noise has been a subject of interest for years. The first work of this scope were published at the turn of the twentieth century by Knudsen (KNUDSEN et al., 1948) and G. Wenz (WENZ, 1962). Disturbances called "shipping noise" are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are...

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Rok 2012

• Tinnitus Therapy Based on High-Frequency Linearization Principles - Preliminary Results

  Publikacja

  • T. Poremski
  • B. Kostek

  - Archives of Acoustics - Rok 2012

  The aim of this work is to present problems related to tinnitus symptoms, its pathogenesis, hypotheses on tinnitus causes, and therapy treatment to reduce or mask the phantom noise. In addition, the hypothesis on the existence of parasitic quantization that accompanies hearing loss has been recalled. Moreover, the paper describes a study carried out by the Authors with the application of high-frequency dither having specially formed...

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• Theoretical studies of nonlinear generation efficiency in a bubble layer

  Publikacja

  • A. Baranowska

  - Archives of Acoustics - Rok 2012

  Celem pracy jest teoretyczna analiza propagacji fal o dużym natężeniu w warstwie z pęcherzykami. Przedstawiono model matematyczny zjawiska w tym omówiono problem wyznaczania prędkości fazowej, współczynnika tłumienia i częstotliwości rezonansowej pęcherzyków. Badano zmiany amplitud pierwszej i drugiej harmonicznej ciśnienia fali odbitej i bieżącej w funkcji grubości warstwy oraz względnej koncentracji pęcherzyków. Rozważano pęcherzyki...

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Rok 2015

• Thermal Self-Action of Acoustic Beams Containing Several Shock Fronts

  Publikacja

  • A. Perelomova

  - Archives of Acoustics - Rok 2015

  Thermal self-action of an acoustic beam with one discontinuity or several shock fronts is studied in a Newtonian fluid. The stationary self-action of a single sawtooth wave with discontinuity (or some integer number of these waves), symmetric or asymmetric, is considered in the cases of self-focusing and self- defocusing media. The results are compared with the non-stationary thermal self-action of the periodic sound. Thermal self-action...

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• Study of Noise Propagation for Small Vessels

  Publikacja

  • M. Weryk
  • E. Kozaczka
  • G. Grelowska

  - Archives of Acoustics - Rok 2015

  The paper presents the results of the noise propagation analysis in ship structures tested in a number of AHTS (Anchor Handling Tug Supply) vessels. Statistical Energy Analysis (SEA) based on numerical model developed specially for the purpose of this numerical investigation were conducted. This numerical model enabled the analysis of both the structural elements and the acoustic spaces. For the detailed studies 47 points fixed...

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Rok 2008

• The noise-induced harmful effect assessment based on the properties of the human hearing system

  Publikacja

  • J. Kotus
  • B. Kostek

  - Archives of Acoustics - Rok 2008

  A new way of assessment of noise-induced harmful effects on human hearing system is presented in the paper. The method takes into consideration properties of the human hearing system. The pro-posed method determines the cumulative impact on hearing system produced by the excessive noise. Based on the predicted effects of the noise exposure, the new types of noise indicators were developed. The evaluation of these indicators was...

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Rok 2005

• System of speech signal processing and visualisation for linguistic purposes

  Publikacja

  • K. Wojan

  - Archives of Acoustics - Rok 2005

Rok 2011

• Study of preference for surround microphone techniques, used in the recording of choir and instrumental ensemble

  Publikacja

  • B. Kostek
  • A. Sitek

  - Archives of Acoustics - Rok 2011

  The aim of this paper is to describe the process of choosing the best surround microphone technique for recording of choir with an instrumental ensemble. First, examples of multichannel microphone techniques including those used in the recording are described. Then, the assumptions and details of music recording in Radio Gdansk Studio are provided as well as the process of mixing of the multichannel recording. The extensive subjective...

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Rok 2010

• Studies of Nonlinear Sound Dynamics in Fluids Based on the Caloric Equation of State

  Publikacja

  • A. Perelomova
  • P. Wojda

  - Archives of Acoustics - Rok 2010

  The sound speed and parameters of nonlinearity B/A, C/A in a fluid are expressed in terms of coefficients in the Taylor series expansion of an excess internal energy, in powers of excess pressure and density. That allows to conclude about features of the sound propagation in fluids, the internal energy of which is known as a function of pressure and density. The sound speed and parameters of nonlinearity in the mixture consisting...

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Rok 2016

• Standing Waves in a Rectangular Resonator Containing Acoustically Active Gases

  Publikacja

  • A. Perelomova

  - Archives of Acoustics - Rok 2016

  The distribution of perturbations of pressure and velocity in a rectangular resonator is considered. A resonator contains a gas where thermodynamic processes take place, such as exothermic chemical reaction or excitation of vibrational degrees of a molecule’s freedom. These processes make the gas acoustically active under some conditions. We conclude that the incident and reflected compounds of a sound beam do not interact in the...

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