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Wyświetlanie 1-15 z 120
Tytuł:
A Novel Method for Determining Optimum Dimension Ratios for Small Rectangular Rooms
Autorzy:
Meissner, M.
Powiązania:
https://bibliotekanauki.pl/articles/177897.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
room acoustics
small room
optimum dimension ratios
room impulse response
frequency room response
Opis:
A new method for determining optimum dimension ratios for small rectangular rooms has been presented. In a theoretical model, an exact description of the room impulse response was used. Based on the impulse response, a frequency response of a room was calculated to find changes in the sound pressure level over the frequency range 20-200 Hz. These changes depend on the source and receiver positions, thus, a new metric equivalent to an average frequency response was introduced to quantify the overall sound pressure variation within the room for a selected source position. A numerical procedure was employed to seek a minimum value of the deviation of the sound pressure level response from a smooth fitted response determined by the quadratic polynomial regression. The most smooth frequency responses were obtained when the source was located at one of the eight corners of a room. Thus, to find the best possible dimension ratios, in the numerical procedure the optimal source position was assumed. Calculation results have shown that optimum dimension ratios depend on the room volume and the sound damping inside a room, and for small and medium volumes these ratios are roughly 1 : 1.48 : 2.12, 1 : 1.4 : 1.89 and 1 : 1.2 : 1.45. When the room volume was suitably large, the ratio 1 : 1.2 : 1.44 was found to be the best one.
Źródło:
Archives of Acoustics; 2018, 43, 2; 217-225
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic Characterization of a Room : Study Case Between Simulation and a Portable Method
Autorzy:
Ibarra-Zarate, David
Padilla-Ortiz, Ana Laura
Powiązania:
https://bibliotekanauki.pl/articles/176728.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
architectural acoustics
acoustical parameters of room
room acoustics
mobile devices
Opis:
Large venues and auditoriums are commonly associated with their astounding architecture. Their acoustic quality is an essential factor in its qualification as a great and functional, or a badly designed place. However, acoustics is often overlooked during the design stage of a building due to the complexity and high cost of the measurements involved. For this reason, it is important to explore more accessible ways to implement acoustics evaluations. The aim of this work is to compare typical experimental measuring methods and the use of mobile devices to assess the acoustic quality of a room. These measurements are contrasted with the software simulation of the same acoustical space. The results show that the mobile system can be used for professional measurements with low restrictions in the frequency range of interest of this study (90 Hz to 4000 Hz).
Źródło:
Archives of Acoustics; 2020, 45, 1; 153-163
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Decay Times from Noisy Room Responses with Pure-Tone Excitation
Autorzy:
Meissner, M.
Powiązania:
https://bibliotekanauki.pl/articles/177891.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
room acoustics
reverberation
decay times
room response
background noise
coupled rooms
Opis:
Reverberant responses are widely used to characterize acoustic properties of rooms, such as the early decay time (EDT) and the reverberation times T20 and T30. However, in real conditions a sound decay is often deformed by background noise, thus a precise evaluation of decay times from noisy room responses is the main problem. In this paper this issue is examined by means of numerical method where the decay times are estimated from the decay function that has been determined by nonlinear polynomial regression from a pressure envelope obtained via the discrete Hilbert transform. In numerical experiment the room responses were obtained from simulations of a sound decay for two-room coupled system. Calculation results have shown that background noise slightly affects the evaluation of reverberation times T20 and T30 as long as the signal-to-noise ratio (SNR) is not smaller than about 25 and 35 dB, respectively. However, when the SNR is close to about 20 and 30 dB, high overestimation of these times may occur as a result of bending up of the decay curve during the late decay.
Źródło:
Archives of Acoustics; 2013, 38, 1; 47-54
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustics of Orthodox Churches in Poland
Autorzy:
Małecki, P.
Wiciak, J.
Nowak, D.
Powiązania:
https://bibliotekanauki.pl/articles/176358.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
orthodox churches
room acoustic
Opis:
An Orthodox church as a building expresses the Eastern Orthodox spirituality – all the details and general aspects have a deep and philosophical meaning. The architecture, being an illustration of the character of the Orthodox Church liturgy, has become a natural component of the cultural landscape of Poland and Eastern Europe. Acoustic research into Orthodox churches has so far been marginalized. Up to now, only a few churches of this type have been studied. The article is a review of the acoustic environment of churches in Poland. Churches, differing in terms of size, architectural style and other quantities, were chosen and acoustic measurements were made. The results of the measurements have been analyzed and collated. In particular, a detailed analysis and comparison was made for reverberation time as a function of frequency, due to the largest differences in this parameter between the rooms.
Źródło:
Archives of Acoustics; 2017, 42, 4; 579-590
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computing Impulse Response of Room Acoustics Using the Ray-Tracing Method in Time Domain
Autorzy:
Alpkocak, A.
Sis, M. K.
Powiązania:
https://bibliotekanauki.pl/articles/177974.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
room acoustics
acoustics simulation
Opis:
This paper proposes a new approach for calculating the impulse response of room acoustics. Impulse response provides unique characterization of any discrete lineartime invariant (LTI) systems. We assume that the room is a linear time-invariant system and the impulse response is calculated simply by sending a Dirac Impulse into the system as input and getting the response from the output. Then, the output of the system is represented as a sum of time-shifted weighted impulse responses. Both mathematical justifications for the proposed method and results from simulation software developed to evaluate the proposed approach are presented in detail.
Źródło:
Archives of Acoustics; 2010, 35, 4; 505-519
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing the Acoustical Climate of Underground Stations
Autorzy:
Nowicka, E.
Powiązania:
https://bibliotekanauki.pl/articles/90611.pdf
Data publikacji:
2007
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
room acoustics
long enclosure
Opis:
Designing a proper acoustical environment—indispensable to speech recognition—in long enclosures is difficult. Although there is some literature on the acoustical conditions in underground stations, there is still little information about methods that make estimation of correct reverberation conditions possible. This paper discusses the assessment of the reverberation conditions of underground stations. A comparison of the measurements of reverberation time in Warsaw’s underground stations with calculated data proves there are divergences between measured and calculated early decay time values, especially for long source–receiver distances. Rapid speech transmission index values for measured stations are also presented.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2007, 13, 4; 427-431
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Operating tasks scheduling system in engine room - mathematical foundations
Autorzy:
Kamiński, P.
Powiązania:
https://bibliotekanauki.pl/articles/247746.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
engine room
managing
scheduling
Opis:
The work contains the proposal to solution of one aspect of the marine power plant management problem with o, which is the allotment of operating tashs to operators in engine room. Frequent causes of ship detentions by port authorities are abnormalities of marine power plant functioning. Each extended ship lay time inport results in a was te of ship operating time thus costs rise to ship owners. This is connected with improper marine power plant management. In order to avoid this, a ship engineer should have at his disposal a computer aided system supporting him in managing the marine power plant. Such a system can be worked out on the condition that a mathematical model, which represents the decision - making proces s ofan engineer has been built. This workpresents approach to the problem ofone aspect in engine room managing what is operating task scheduling for the staff. The chief engineer is responsible for all engine room operating processes. He must make the plan for all activities to secure his correct operation. The use separately of several mathematical methods is not so effective, as then, when they are the put-upon in frames in coherent system and conduct as a consistent procedure. The main problem In this paper was create the mathematical model of system to assigning operational tasks in engine room, which would permitted to choice the optimum variant of tasks schedule.
Źródło:
Journal of KONES; 2010, 17, 4; 221-227
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Subjective Assessment of Concert Halls: a Common Vocabulary for Music Lovers and Acousticians
Autorzy:
Giménez, A.
Cibrian, R. M.
Cerda, S.
Powiązania:
https://bibliotekanauki.pl/articles/176648.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
room acoustics
subjective evaluation
Opis:
In recent years we have interviewed members of the audience after musical performances and asked them to evaluate the acoustics of the concert halls. A group of "music lovers" (with a high level of musical training and experience) and "acousticians" (with a wide knowledge of the physical characteristics of sound transmission) also attended each performance and answered the same questions as the general public. This group thereby served as a control group when evaluating surveys of the general public. In this paper, the results obtained when analyzing these control group surveys are presented. This analysis shows that a common vocabulary exists between music lovers and acousticians when rating a hall, although the grouping of the questions for each factor depends on the training of the respondents.
Źródło:
Archives of Acoustics; 2012, 37, 3; 331-340
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Reverberant Properties of Enclosures via a Method Employing a Modal Representation of the Room Impulse Response
Autorzy:
Meissner, M.
Powiązania:
https://bibliotekanauki.pl/articles/177946.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
room acoustics
indoor reverberation
room impulse response
modal expansion method
decay times
Opis:
A theoretical method has been presented to describe sound decay in enclosures and simulate the room impulse response (RIR) employed for prediction of the indoor reverberation characteristics. The method was based on a solution of wave equation with the form of a series whose time-decaying components represent responses of acoustic modes to an impulse sound source. For small sound absorption on room walls this solution was found by means of the method of variation of parameters. A decay function was computed via the time-reverse integration of the squared RIR. Computer simulations carried out for a rectangular enclosure have proved that the RIR function reproduces the structure of a sound field in the initial stage of sound decay sufficiently well. They have also shown that band-limitedness of the RIR has evident influence on the shape of the decay function and predicted decay times.
Źródło:
Archives of Acoustics; 2016, 41, 1; 27-41
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Wall Impedance Phase Angle on Indoor Sound Field and Reverberation Parameters Derived from Room Impulse Response
Autorzy:
Meissner, Mirosław
Zieliński, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/31340118.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
room acoustics
complex wall impedance
indoor sound field
room impulse response
reverberation parameters
Opis:
Accurate definition of boundary conditions is of crucial importance for room acoustic predictions because the wall impedance phase angle can affect the sound field in rooms and acoustic parameters applied to assess a room reverberation. In this paper, the issue was investigated theoretically using the convolution integral and a modal representation of the room impulse response for complex-valued boundary conditions. Theoretical considerations have been accompanied with numerical simulations carried out for a rectangular room. The case of zero phase angle, which is often assumed in room acoustic simulations, was taken as a reference, and differences in the sound pressure level and decay times were determined in relation to this case. Calculation results have shown that a slight deviation of the phase angle with respect to the phase equal to zero can cause a perceptual difference in the sound pressure level. This effect was found to be due to a change in modal frequencies as a result of an increase or decrease in the phase angle. Simulations have demonstrated that surface distributions of decay times are highly irregular, while a much greater range of the early decay time compared to the reverberation time range indicates that a decay curve is nonlinear. It was also found that a difference between the decay times predicted for the complex impedance and real impedance is especially clearly audible for the largest impedance phase angles because it corresponds approximately to 4 just noticeable differences for the reverberation metrics.
Źródło:
Archives of Acoustics; 2022, 47, 3; 343-353
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concert Hall Sound Clarity: A Comparison of Auditory Judgments and Objective Measures
Autorzy:
Miśkiewicz, A.
Rogala, T.
Rościszewska, T.
Rudzki, T.
Fidecki, T.
Powiązania:
https://bibliotekanauki.pl/articles/177211.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound clarity
room acoustics
psychoacoustics
Opis:
The purpose of the study was to compare auditory judgments of sound clarity of music examples recorded in a concert hall with predictions of clarity made from the impulse response signal recorded in the same hall. Auditory judgments were made with the use of two methods: by rating sound clarity on a numerical scale with two endpoints, and by absolute magnitude estimation. Results obtained by both methods were then compared against the values of clarity indices, C80 and C50, determined from the impulse response of the concert hall, measured in places in which the microphone was located during recording of music examples. Results show that auditory judgments of sound clarity and predictions made from the C80 index yield a similar rank order of data, but the relation between the C80 scale and perceived sound clarity is nonlinear. The data also show that the values of C80 and C50 indices are in very close agreement.
Źródło:
Archives of Acoustics; 2012, 37, 1; 41-46
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inflammatory tumor of the base of the tongue as a clinical presentation of HIV infection
Autorzy:
Zwierzyńska, Klaudyna
Gotlib, Tomasz
Niemczyk, Kazimierz
Powiązania:
https://bibliotekanauki.pl/articles/1398944.pdf
Data publikacji:
2021
Wydawca:
Index Copernicus International
Tematy:
emergency room
HIV
tongue tumor
Opis:
Introduction: AIDS is a fatal disease that impairs the immunity, increasing the risk of developing opportunistic infections. Case report: We present a case of a 47-year-old patient from the ER, with bleeding from a tongue tumor. The patient reported that he had lost 25 kg in about six months and complained of swallowing disorders. HIV infection was confirmed in the patient during the diagnosis. The inflammatory tumor of the tongue was the only manifestation of HIV infection.
Źródło:
Polski Przegląd Otorynolaryngologiczny; 2021, 10, 1; 62-64
2084-5308
2300-7338
Pojawia się w:
Polski Przegląd Otorynolaryngologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Virtual Acoustics at the Service of Music Performance and Recording
Autorzy:
Woszczyk, W.
Ko, D.
Leonard, B.
Powiązania:
https://bibliotekanauki.pl/articles/177293.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
virtual acoustics
active acoustic architecture
room acoustics
room impulse respons
low-latency convolution
performer-room interaction
music recording
acoustic enhancement
active acoustics
Opis:
Virtual or active acoustics refers to the generation of a simulated room response by means of elec- troacoustics and digital signal processing. An artificial room response may include sound reflections and reverberation as well as other acoustic features mimicking the actual room. They will cause the listener to have an impression of being immersed in virtual acoustics of another simulated room that coexists with the actual physical room. Using low-latency broadband multi-channel convolution and carefully measured room data, optimized transducers for rendering of sound fields, and an intuitive touch control user in- terface, it is possible to achieve a very high perceived quality of active acoustics, with a straightforward adjustability. The electroacoustically coupled room resulting from such optimization does not merely produce an equivalent of a back-door reverberation chamber, but rather a fully functional complete room superimposed on the physical room, yet with highly selectable and adjustable acoustic response. The utility of such active system for music recording and performance is discussed and supported with examples.
Źródło:
Archives of Acoustics; 2012, 37, 1; 109-113
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examination of the Effect of a Sound Source Location on the Steady-State Response of a Two-Room Coupled System
Autorzy:
Meissner, M.
Powiązania:
https://bibliotekanauki.pl/articles/177058.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coupled room system
steady-state room response
potential and kinetic energy densities
localization of modes
Opis:
In this paper, the computer modelling application based on the modal expansion method is developed to study the influence of a sound source location on a steady- state response of coupled rooms. In the research, an eigenvalue problem is solved numerically for a room system consisting of two rectangular spaces connected to one another. A numerical procedure enables the computation of shape and frequency of eigenmodes, and allows one to predict the potential and kinetic energy densities in a steady-state. In the first stage, a frequency room response for several source positions is investigated, demonstrating large deformations of this response for strong and weak modal excitations. Next, a particular attention is given to studying how the changes in a source position influence the room response when a source frequency is tuned to a resonant frequency of a strongly localized mode.
Źródło:
Archives of Acoustics; 2011, 36, 4; 761-775
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Speech Intelligibility Test for Polish Language – Relation to the Acoustic Properties of Classrooms and Comparison to Other Languages
Autorzy:
Radosz, J.
Powiązania:
https://bibliotekanauki.pl/articles/177319.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
speech intelligibility
classroom
school
room acoustics
Opis:
Numerous studies have shown that teachers often speak louder in classrooms because of the acoustic properties of the spaces. To improve the acoustics in classrooms, it is necessary to develop relevant acoustic criteria. Existing evaluation scales for parameters of room acoustics have been developed on the basis of studies of adults for a variety of languages (e.g. Dutch and English). One of the issues still not fully recognized is the effect of the respondents’ language and age on the results of speech intelligibility tests. The aim of the study was to recognize the possibility of applying some international guidelines for room acoustics developed on the basis of adult studies to classrooms in Polish schools. This paper presents a study of the speech intelligibility of Polish-speaking children (10–13 years old) in conjunction with parameters of room acoustics. It also compares studies of speech intelligibility for other languages. The study confirmed a relationship between the results of speech intelligibility tests and speech transmission index STI for classrooms with varied acoustics. It also showed that the results of Polish word test are similar to results of English tests (Anderson, Kalb, 1987; Jacob et al., 1990).
Źródło:
Archives of Acoustics; 2018, 43, 1; 129-135
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 120

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