Contents of issue 3, vol. 28 (2003)

  1. W.A. Barbosa, A. Lenzi, P.H.T. Zaninin, Parameter analysis of vibratory energy flow in a hermetic compressor by statistical energy analysis, Archives of Acoustics, 28, 3, 151-159
  2. T. Boczar, S. Wolny, Application of statistical analysis in result repeatability evaluation of acoustic emission measurements generated by partial discharges, Archives of Acoustics, 28, 3, 161-179
  3. J. Lemańska, A.P. Sęk, W. Rybicka, Masking in the modulation rate domain, Archives of Acoustics, 28, 3, 181-189
  4. S. Weyna, Identification of reflection, diffraction and scattering effects in real acoustic flow fields, Archives of Acoustics, 28, 3, 191-203
  5. Chronicle, The Fiftieth Open Seminar on Acoustics (OSA 2003), Archives of Acoustics, 28, 3, 205-248
  6. Chronicle, The Fiftieth Open Seminar on Acoustics - Satellite Workshop "Speech Analysis, Synthesis and Recognition in Technology, Linguistics and Medicine", Archives of Acoustics, 28, 3, 249-262
  7. Chronicle, In Memoriam - Professor Zygmunt Kleszczewski, Archives of Acoustics, 28, 3, 263-265
  8. Chronicle, In Memoriam - Professor Zbigniew Kaczkowski, Archives of Acoustics, 28, 3, 267-268
  9. Chronicle, Dissertation, Archives of Acoustics, 28, 3, 269
W.A. Barbosa*, A. Lenzi**, P.H.T. Zaninin*, Parameter analysis of vibratory energy flow in a hermetic compressor by statistical energy analysis
*Laboratório de Acústica Ambiental - Departamento de Engenharia Mecânica
Universidade Federal do Paraná
81531990 Curitiba - PR, Brasil
e-mail: zannin@demec.ufpr.br
**Laboratório de Vibraçoes e Acústica - Departamento de Engenharia Mecânica
Universidade Federal de Santa Catarina
88040-900 Florianópolis - SC, Brasil
e-mail: arcanjo@emc.ufsc.br
This work deals with the problem of vibratory energy flow from the internal electrical motor-compressor assembly (kit) to the shell of a hermetic compressor. The theoretical model is based on Statistical Energy Analysis. Shell and body vibratory energies have been measured at a standard operation condition, and the coupling loss factor thus obtained agreed well with predicted values calculated from impedance data. Several parameters, such as body and shell impedance, spring and shell loss factor, and model of the spring (tension and compression) were varied and their effects upon the compressor noise analyzed. Good agreement between theoretical and experimental results was observed.


T. Boczar, S. Wolny, Application of statistical analysis in result repeatability evaluation of acoustic emission measurements generated by partial discharges
Department of Electrical Engineering and Automatic Control
Technical University of Opole
K. Sosnkowskiego 31, 45-272 Opole, Poland
The subject matter of this paper deals with the improvement of the acoustic emission (AE) method in diagnostics of insulation systems of power appliances. The paper presents the results of the statistical analysis of the AE pulses generated by the setups modeling basic partial discharge (PD) forms that can occur in oil insulation systems. Especially, the results of parametric and non-parametric tests of quality of fit are presented that were carried out in order to determine the probability distribution of the AE pulses measured, to test the repeatability of the frequency analysis results obtained, and to check the influence of the factors that can disturb this repeatability. The statistical analyses were carried out based on the values of three descriptors, i.e. shape coefficient, peak coefficient and median frequency, which make the identification of basic PD forms occurring in insulation oil possible.


J. Lemańska, A.P. Sęk, W. Rybicka, Masking in the modulation rate domain
Institute of Acoustics, Adam Mickiewicz University
Umultowska 85, 60-615 Poznań, Poland
e-mail: lema@amu.edu.pl; oleksek@amu.edu.pl; rywi@amu.edu.pl
This study examines the amplitude modulation (AM) detection in the presence of a masking modulating signal. The detection thresholds of sinusoidal amplitude modulation were measured for a 4 kHz sinusoidal carrier. The masking modulators were a 16 Hz tone, a bandwidth of a low-noise noise centered at 16 Hz with a bandwidth of 2 or 8 Hz, and the gaussian noise centered at 16 Hz with a 8 Hz bandwidth. A 3AFC procedure was used. The results obtained suggest the existence of a masking effect in the modulation rate domain. This form of masking is the most effective one when the modulation frequency of the masking signal is close to the masker or, in the spectral range of masking, to the modulation signal. These results are consistent with experimental data, which suggest the existence of frequency selectivity and tuning in the amplitude modulation domain. The results obtained are consistent with the idea of a second stage of filtering in the auditory system by means of so-called modulation filters. It seems that the auditory system performs a limited resolution spectral analysis of the signal amplitude envelope. However, it is necessary to stress that the frequency selectivity in the amplitude modulation domain is not so evident as the selectivity in the audio frequency domain.


S. Weyna, Identification of reflection, diffraction and scattering effects in real acoustic flow fields
Department of Applied Vibroacoustics
Technical University of Szczecin
Al. Piastów 41, 71-065 Szczecin, Poland
e-mail: stefan.weyna@ps.pl
In contrast to the classically described acoustical fields with acoustical pressure distributions (scalar effects), the graphical presentation of the acoustic energy flow in real-life acoustic fields as a vector mapping, can explain many particulars concerning the areas in which it is difficult to make a theoretical analysis (direct and near field, vortex flow, effects of scattering on obstacles, reflection on partitions, efficiency of acoustics barrier, etc.). With the experimental application of the sound intensity (SI) measurement method in real-life fields as well as the technique of presentation the results in a 2D and a 3D graphical form, numerous examples illustrate the results of applying the SI measurement for practical problems presented in the article. Concerning the intensity vector distribution of the real near and fare field, the paper presents the paths of the acoustic energy flow over the barriers and the form of the acoustical radiation field of vibrating structures. This type of information enriches the knowledge about vector acoustic fields and the mechanism of the acoustic energy flux through the real partitions.


Chronicle: The Fiftieth Open Seminar on Acoustics (OSA 2003)
Gliwice - Szczyrk, Poland, September 22-27, 2003
The most important conference of Polish acousticians is the annual Open Seminar on Acoustics. The seminar provides researchers with an opportunity to present their accomplishments and share knowledge gained in carrying out investigations. On most occasions the conference is attended not only by Polish acousticians but also by prominent foreign experts in the field of acoustical research.
This year the meeting will have a very special character since we shall celebrate the 50-th edition of the Open Seminar on Acoustics. Moreover, this Golden Jubilee Seminar coincides with the 40-th anniversary of the foundation of the Polish Acoustical Society.
The organizers have received over 100 abstracts of lectures to be presented during the 2003 Golden Jubilee OSA. We are grateful to all authors for their generous response to our call. In keeping with the adopted practice, the submitted abstracts have been grouped into special interest sections. The lectures subsequently forwarded will be assessed by reviewers and if approved shall be published in the Proceedings of the Fiftieth Open Seminar on Acoustics. Below are listed the particular research-field categories applied to classify the abstracts and papers submitted for presentation:
  • Acoustic Signal Processing
  • Active Methods and Vibroacoustics
  • Biomedical Acoustics
  • Computer Acoustics
  • Electroacoustics
  • Environmental Acoustics
  • Hydroacoustics
  • Musical Acoustics
  • Physical Acoustics
  • Speech and Hearing

  • Chronicle: Satellite Workshop "Speech Analysis, Synthesis and Recognition in Technology, Linguistics and Medicine"
    Szczyrk, Poland, September 22-27, 2003
    The Satellite Workshop "Speech Analysis, Synthesis and Recognition in Technology, Linguistics and Medicine", organized by the Polish Phonetic Association and Accompanying the 50-th Open Seminar in Acoustics (Szczyrk, September 2003), offered us an opportunity to present and discuss papers related to speech and language technology. The meeting was intended to focus on the progress in this field achieved by Polish researchers and for the Polish language, but more general topics were also included and some prominent guests from abroad were invited.
    The Polish Phonetic Association PPA (PTFon - Polskie Towarzystwo Fonetyczne) conducts and coordinates research in linguistic, technological and medical phonetics with special reference to Polish speech. The linguistic research concentrates on descriptive and historical phonetics; medical-phonetic investigations largely fall in the domain of phoniatrics; technological phonetic concerns acoustic analysis, synthesis, and recognition, as well as speech translation. A large body of results obtained so far have been reported at the research seminars and conferences organized by PPA in the 80-ies and 90-ies. They were mostly published in seven volumes of Speech and Language Technology (1997-2003). They were also presented at the international conference on speech prosody organized in Kraków (2000). The Association has three regional branches in Poznań, Kraków, and Warszawa. More information can be obtained at http://main.amu.edu.pl/~fonetyka

    In Memoriam - Professor Zygmunt Kleszczewski
    Professor Zygmunt Kleszczewski

    On May 7th, 2003 Prof. dr hab. Zygmunt Kleszczewski, an outstanding scientist and academic teacher, for many years actively engaged member of the Polish Acoustical Society, has left us for ever.
    Professor Kleszczewski was born on January 5th, 1943, in Ciążkowice. In the year 1966 he graduated from the Faculty of Mathematics and Physics at the University of Warsaw (specializing in nuclear physics). On September 1st of this same year he started work at the Chair of Physics, Faculty of Electrical Engineering at Silesian University of Technology in Gliwice. When in 1969 the Faculty of Mathematics and Physics was established, he became one of its staff, to which he belong until his death. At the Silesian University of Technology in Gliwice he passed all the levels of his academic career, viz. assistant (1966-1972), adjunct (1972-1981), assistant professor (1981-1997), professor (1997-1999) and full professor (1999-2003).


    In Memoriam - Professor Zbigniew Kaczkowski
    Professor Zbigniew Kaczkowski

    Professor Kaczkowski was born on March 26, 1932. In 1956 he completed his study in the field of Telecommunication at the Technical University of Warsaw. In 1964 he got the doctoral degree in Technical Sciences and in 1972 - the habilitation doctoral degree at the Institute of Fundamental Technological Research of the Polish Academy of Sciences in Warsaw, where he was active in the Department of Electronics in the period 1954-1966. Next he passed with this Department to the Institute of Physics of the Polish Academy of Sciences.
    He was a modest, good, joyful and understanding person. He often entertained the members of scientific symposia with his witty short poems. He was the member of the Committee on Acoustics of the Polish Academy of Sciences and, in the period 1990-1993, the chairman of the Warsaw Section of the Polish Acoustical Society.
    Professor Zbigniew Kaczkowski died on April 23, 2003. We will miss him very much.


    Chronicle, Doctor's thesis: Perceptual filtration of audio signals with the use of intelligent decision algorithms
    by Rafał Królikowski Gdańsk University of Technology
    Supervisor: Prof. Andrzej Czyżewski
    Abstract: The research presented in the disseratation addresses the problem of non-stationary acoustic noise reduction in audio recordings. Its objective was to develop and to test new methods of audio restoration, which would employ psychoacoustics and intelligent decision systems. For this purpose a few novel approaches were proposed. The first one, perceptual filtration, employs some properties of the human hearing system in order to mask the parasite interfering noise and exploits various mathematical models of the auditory system. The second method refers to the estimation of parameters of non-stationary noise. It is based on parametrisation and quantisation of interfering noise, and additionally employs the following decision systems: neural networks and rough set-based inference system. Furthermore, some algorithmic solutions based on the mentioned above methods were proposed along with exemplary implementations. The obtained results of the experiments and the detailed discussion have also been included in the Ph.D. dissertation.

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