Journal articles: 'Reverberation Impact'

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Nowoświat, Artur. "Impact of Temperature and Relative Humidity on Reverberation Time in a Reverberation Room." Buildings 12, no. 8 (August 21, 2022): 1282. http://dx.doi.org/10.3390/buildings12081282.

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Changes in acoustic parameters measured in a room may depend on the location and orientation of the sound source and microphones or on the reverberation conditions of the room. As was found in the research presented in this publication, reverberation in a room is also influenced by thermo-hygrometric conditions. The article presents an experimental analysis involving the impact of temperature and relative air humidity in a room on reverberation time. Since it is very difficult to control the temperature and relative humidity in real conditions, the tests were carried out both in laboratory conditions and with the use of simulations. For this purpose, the results of the reverberation time measurements in the reverberation chamber for various thermo-hygrometric conditions were obtained. Then, the reverberation chamber was modeled in the ODEON Version 11.0 program, and after the validation of the model, a series of simulations were performed, demonstrating the changes in the reverberation time as a function of temperature and relative air humidity. The results are presented in both a two-dimensional and three-dimensional version, i.e., the dependence of the reverberation time as a function of two variables: air temperature and relative humidity.

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Hung, Alex Ling Yu, Edward Chen, and John Galeotti. "Weakly- and Semisupervised Probabilistic Segmentation and Quantification of Reverberation Artifacts." BME Frontiers 2022 (March 1, 2022): 1–15. http://dx.doi.org/10.34133/2022/9837076.

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Objective and Impact Statement. We propose a weakly- and semisupervised, probabilistic needle-and-reverberation-artifact segmentation algorithm to separate the desired tissue-based pixel values from the superimposed artifacts. Our method models the intensity decay of artifact intensities and is designed to minimize the human labeling error. Introduction. Ultrasound image quality has continually been improving. However, when needles or other metallic objects are operating inside the tissue, the resulting reverberation artifacts can severely corrupt the surrounding image quality. Such effects are challenging for existing computer vision algorithms for medical image analysis. Needle reverberation artifacts can be hard to identify at times and affect various pixel values to different degrees. The boundaries of such artifacts are ambiguous, leading to disagreement among human experts labeling the artifacts. Methods. Our learning-based framework consists of three parts. The first part is a probabilistic segmentation network to generate the soft labels based on the human labels. These soft labels are input into the second part which is the transform function, where the training labels for the third part are generated. The third part outputs the final masks which quantifies the reverberation artifacts. Results. We demonstrate the applicability of the approach and compare it against other segmentation algorithms. Our method is capable of both differentiating between the reverberations from artifact-free patches and modeling the intensity fall-off in the artifacts. Conclusion. Our method matches state-of-the-art artifact segmentation performance and sets a new standard in estimating the per-pixel contributions of artifact vs underlying anatomy, especially in the immediately adjacent regions between reverberation lines. Our algorithm is also able to improve the performance of downstream image analysis algorithms.

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Didier, Paul, Cédric Van hoorickx, and Edwin Reynders. "Numerical study of the impact of reverberation room design and test parameters on sound absorption measurements." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 4 (August 1, 2021): 2372–83. http://dx.doi.org/10.3397/in-2021-2120.

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The measurement of sound absorption in reverberation rooms following the ISO 354:2003 standard relies on Sabine's equation to derive absorption coefficients from reverberation times. This equation assumes perfect diffusivity, i.e. the sound field is composed of many statistically independent plane waves with uniformly distributed spatial phases, themselves uncorrelated to the corresponding amplitudes. In this work, both existing and fictitious reverberation rooms are numerically modelled using the finite element method. Finite porous absorbers are introduced in the rooms as equivalent fluid models. Standardized sound absorption measurement are simulated in the rooms through the determination of reverberation times. The respective effects of the sample size, sample placement, source positioning, and presence of finite panel diffusers are investigated. The resulting absorption coefficients are then confronted to the theoretical values in a perfectly diffuse sound field, that interacts with a baffled, finite-sized absorber, as obtained with a hybrid deterministic-statistical energy analysis model. The process notably underlines the strong, yet often disregarded, beneficial effect of panel diffusers at low frequencies in highly regularly-shaped rooms. Another conclusion of this work is that reverberation room design represents a crucial factor that can influence sound absorption measurements at low frequencies.

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Prodi, Nicola, and Chiara Visentin. "Impact of Background Noise Fluctuation and Reverberation on Response Time in a Speech Reception Task." Journal of Speech, Language, and Hearing Research 62, no. 11 (November 22, 2019): 4179–95. http://dx.doi.org/10.1044/2019_jslhr-h-19-0180.

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Purpose This study examines the effects of reverberation and noise fluctuation on the response time (RT) to the auditory stimuli in a speech reception task. Method The speech reception task was presented to 76 young adults with normal hearing in 3 simulated listening conditions (1 anechoic, 2 reverberant). Speechlike stationary and fluctuating noise were used as maskers, in a wide range of signal-to-noise ratios. The speech-in-noise tests were presented in a closed-set format; data on speech intelligibility and RT (time elapsed from the offset of the auditory stimulus to the response selection) were collected. A slowing down in RTs was interpreted as an increase in listening effort. Results RTs slowed down in the more challenging signal-to-noise ratios, with increasing reverberation and for stationary compared to fluctuating noise, consistently with a fluctuating masking release scheme. When speech intelligibility was fixed, it was found that the estimated RTs were similar or faster for stationary compared to fluctuating noise, depending on the amount of reverberation. Conclusions The current findings add to the literature on listening effort for listeners with normal hearing by indicating that the addition of reverberation to fluctuating noise increases RT in a speech reception task. The results support the importance of integrating noise and reverberation to provide accurate predictors of real-world performance in clinical settings.

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Mi, Huan, Gavin Kearney, and Helena Daffern. "Impact Thresholds of Parameters of Binaural Room Impulse Responses (BRIRs) on Perceptual Reverberation." Applied Sciences 12, no. 6 (March 9, 2022): 2823. http://dx.doi.org/10.3390/app12062823.

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This paper presents a study on the perceived importance of different acoustic parameters of Binaural Room Impulse Response (BRIR) rendering. A headphone-based listening test was conducted with twenty expert participants. Three BRIRs generated from simulations of three different rooms were convolved with a dry speech signal and used as reference audio samples. Four BRIR parameters, Initial Time Delay Gap (ITDG), Forward Early Reflections (FER), Reverse Early Reflections (RER) and Late Reverberation (LR) were systematically altered and convolved with a speech signal to generate the test conditions. A staircase method was used to obtain the threshold at which each BRIR parameter was perceived as different from the reference audio sample. The average perceived impact threshold of each parameter was then calculated across the twenty participants. Results show that RER removal and ITDG extension have a clear impact on the perceptual reverberation of speech audio. Subjects were less sensitive to FER removal. The effect of LR removal on perceptual reverberation is hard to distinguish. Therefore, RER and ITDG are of particular importance when designing artificial reverberation algorithms, whilst more research is needed to understand the perceptual contribution of LR. Minor changes in FER and LR are less significant.

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Jeong, Jeong Ho, Jeong Uk Kim, and Jae Gun Jeong. "Floor Impact Sound Pressure Level Characteristics by the Change of Reverberation Time in a Reverberation Chamber." Transactions of the Korean Society for Noise and Vibration Engineering 23, no. 3 (March 20, 2013): 274–81. http://dx.doi.org/10.5050/ksnve.2013.23.3.274.

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Hefner, Brian T., Jie Yang, and Dajun Tang. "Environmentally constrained modeling of mid-frequency transmission loss and reverberation measured during the Target and Reverberation Experiment 2013." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A138—A139. http://dx.doi.org/10.1121/10.0010908.

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The goal of the Target and Reverberation Experiment (TREX13) was to make contemporaneous measurements of mid-frequency (1.5–4 kHz) transmission loss and reverberation with extensive environmental measurements so detailed model/data comparison can be achieved and important environmental factors can be identified for different applications. APL-UW collaborated with ARL-Penn State, led by John R. Preston, to deploy the Five Octave Research Array (FORA) on a “clothesline” about 2.1 m above the seafloor. This fixed-source/receiver configuration helped eliminate uncertainties from the motion of a towed array and allow reverberation measurement along a narrow, 7-km-long section of seafloor. The experiment site had a fairly complex spatial distribution of both sediment type and sediment scattering properties and keeping the FORA in a fixed position was instrumental in understanding and modeling the reverberation. While soft sediments make up only 27% of the sediments by area at the site, it is necessary to account for this spatial dependence so that both transmission loss and reverberation can be modeled using a consistent set of environmental inputs. These models and their implications for our understanding of the environmental factors which most impact mid-frequency reverberation will be discussed. [Work supported by the U.S. Office of Naval Research.]

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Kathleen Bandt, S., and Ralph G. Dacey. "Reverberation index: a novel metric by which to quantify the impact of a scientific entity on a given field." Journal of Neurosurgery 127, no. 3 (September 2017): 694–98. http://dx.doi.org/10.3171/2016.7.jns152387.

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The authors propose a novel bibilometric index, the reverberation index (r-index), as a comparative assessment tool for use in determining differential reverberation between scientific fields for a given scientific entity. Conversely, this may allow comparison of 2 similar scientific entities within a single scientific field. This index is calculated using a relatively simple 3-step process.Briefly, Thompson Reuters' Web of Science is used to produce a citation report for a unique search parameter (this may be an author, journal article, or topical key word). From this citation report, a list of citing journals is retrieved from which a weighted ratio of citation patterns across journals can be calculated. This r-index is then used to compare the reverberation of the original search parameter across different fields of study or wherever a comparison is required.The advantage of this novel tool is its ability to transcend a specific component of the scientific process. This affords application to a diverse range of entities, including an author, a journal article, or a topical key word, for effective comparison of that entity's reverberation within a scientific arena. The authors introduce the context for and applications of the r-index, emphasizing neurosurgical topics and journals for illustration purposes. It should be kept in mind, however, that the r-index is readily applicable across all fields of study.

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de Carolis, Daniele. "The Reverberation Effect of the EU Notion of Abuse of Law on the Italian Tax Legal System: Towards an Enhanced Horizontal Interaction Among National General Anti-Abuse Rules?" Intertax 45, Issue 2 (February 1, 2017): 169–74. http://dx.doi.org/10.54648/taxi2017013.

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In the preface to the seminal book ‘Prohibition of Abuse of Law – A New General Principle of EU Law?’1prof. de la Feria relies on the metaphor of ‘reverberation’ in order to account for the creation and development of an EU principle of abuse of law and its impact on the different Member States’ national legal systems. Building on this idea, this article shows how the reverberation metaphor can effectively be used to explain the impact of the EU notion of abuse of law on the Italian tax legal system and the horizontal interaction of this latter system with other Member States’ legislations. On this reading, the first section illustrates the main features of the reverberation process; the second examines the impact of this process on the Italian tax legal system with particular reference to the process of codification of a national General Anti-Abuse Rule (GAAR); finally, the third section attempts a comparison between the Italian and the English anti-abuse provisions in order to work out an example of possible horizontal interaction between the two national systems.

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Spratford, Meredith, Elizabeth A. Walker, and Ryan W. McCreery. "Use of an Application to Verify Classroom Acoustic Recommendations for Children Who Are Hard of Hearing in a General Education Setting." American Journal of Audiology 28, no. 4 (December 16, 2019): 927–34. http://dx.doi.org/10.1044/2019_aja-19-0041.

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Purpose Classrooms including children who are hard of hearing (CHH) may be modified to manage noise and reverberation and improve speech perception. Little is known about the acoustic characteristics of contemporary general education classrooms that include CHH compared to classrooms of typical peers. We proposed the following research questions about the acoustic environment of general education classrooms including CHH: (a) How reliable are acoustic measurements collected using an iOS device, application, and external microphone? (b) What proportion of classrooms meet the American National Standards Institute's standards for unoccupied noise levels and reverberation? Method A smartphone application was used to measure sound levels, reverberation, and clarity for 164 general education classrooms including CHH. Linear mixed models were used to examine the following: (a) reliability of acoustic measures made using an application and external microphone and (b) predictors of sound levels, reverberation, and clarity for elementary classrooms including CHH. Results Results indicate the application reliably measures classroom acoustics. Classrooms exceeded the American National Standards Institute's recommended noise levels, but met reverberation time guidelines. Grade; heating, ventilation, and air conditioning status; and room volume predicted classroom acoustics. Conclusions As a screening tool, the application was shown to be effective in reliably measuring reverberation and classroom noise levels. The high levels of noise in unoccupied classrooms indicate a need for increased use of noise abatement strategies and the use of remote-microphone systems, especially in classrooms where noise levels cannot feasibly be reduced. Using an application may be a cost-effective method for monitoring important acoustic features that impact children's ability to understand speech in the classroom.

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Dahlen, Unn, Nils Ryden, and Andreas Jakobsson. "Damage identification in concrete using impact non-linear reverberation spectroscopy." NDT & E International 75 (October 2015): 15–25. http://dx.doi.org/10.1016/j.ndteint.2015.04.002.

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Yue, Han, Jorge C. Castellanos, Chunquan Yu, Lingsen Meng, and Zhongwen Zhan. "Localized water reverberation phases and its impact on backprojection images." Geophysical Research Letters 44, no. 19 (October 3, 2017): 9573–80. http://dx.doi.org/10.1002/2017gl073254.

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Cucharero, Jose, Tuomas Hänninen, and Tapio Lokki. "Influence of Sound-Absorbing Material Placement on Room Acoustical Parameters." Acoustics 1, no. 3 (August 7, 2019): 644–60. http://dx.doi.org/10.3390/acoustics1030038.

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The reverberation of a room is often controlled by installing sound absorption panels to the ceiling and on the walls. The reduced reverberation is particularly important in classrooms to maximize the speech intelligibility and in open-plan offices to make spaces more pleasant. In this study, the impact of the placement of the absorption material in a room was measured in a reverberation room and in a mockup classroom. The results show that absorption material is less efficient if it is mounted to the corners or on the edges between the walls and ceiling, if the sound field is more or less diffuse. If the room modes dominate the sound field, the most efficient location for the sound-absorbing material was found at one of the surfaces causing the modes. The results help acoustical consultants to place the absorption material in optimal locations and, generally, minimize the amount of material and save costs.

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Bandiera, R., N. Bucciantini, J. Martín, B. Olmi, and D. F. Torres. "Reverberation of pulsar wind nebulae (I): impact of the medium properties and other parameters upon the extent of the compression." Monthly Notices of the Royal Astronomical Society 499, no. 2 (September 28, 2020): 2051–62. http://dx.doi.org/10.1093/mnras/staa2956.

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ABSTRACT The standard approach to the long-term evolution of pulsar wind nebulae (PWNe) is based on one-zone models treating the nebula as a uniform system. In particular for the late phase of evolved systems, many of the generally used prescriptions are based on educated guesses for which a proper assessment lacks. Using an advanced radiative code, we evaluate the systematic impact of various parameters, like the properties of the supernova ejecta, of the inner pulsar, as well of the ambient medium, upon the extent of the reverberation phase of PWNe. We investigate how different prescriptions shift the starting time of the reverberation phase, how this affects the amount of the compression, and how much of this can be ascribable to the radiation processes. Some critical aspects are the description of the reverse shock evolution, the efficiency by which at later times material from the ejecta accretes on to the swept-up shell around the PWN, and finally the density, velocity, and pressure profiles in the surrounding supernova remnant. We have explicitly treated the cases of the Crab Nebula, and of J1834.9−0846, taken to be representatives of the more and the less energetic pulsars, respectively. Especially for the latter object, the prediction of large compression factors is confirmed, even larger in the presence of radiative losses, also confirming our former prediction of periods of superefficiency during the reverberation phase of some PWNe.

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Jeong, Jeong-Ho, and Jeong-Ok Park. "Repeatability Evaluation of Rubber Ball Impact Sound in a Reverberation Chamber." Transactions of the Korean Society for Noise and Vibration Engineering 29, no. 1 (February 20, 2019): 75–82. http://dx.doi.org/10.5050/ksnve.2019.29.1.075.

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Canning, David, Adrian James, and Bridget M. Shields. "Essex experimental study: The impact of reverberation time on working classrooms." Journal of the Acoustical Society of America 132, no. 3 (September 2012): 2045. http://dx.doi.org/10.1121/1.4755518.

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Kressner, Abigail Anne, Adam Westermann, and Jörg M. Buchholz. "The impact of reverberation on speech intelligibility in cochlear implant recipients." Journal of the Acoustical Society of America 144, no. 2 (August 2018): 1113–22. http://dx.doi.org/10.1121/1.5051640.

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Berg, Soren. "Impact of Reduced Reverberation Time on Sound-Induced Arousals During Sleep." Sleep 24, no. 3 (May 2001): 289–92. http://dx.doi.org/10.1093/sleep/24.3.289.

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Olechowska, Marcelina, Artur Nowoświat, Jan Ślusarek, and Mateusz Latawiec. "The influence of the distribution of sound absorbing materials on the estimation of reverberation time in rooms." E3S Web of Conferences 49 (2018): 00078. http://dx.doi.org/10.1051/e3sconf/20184900078.

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Reverberation time in rooms depends on many factors, e.g. cubature, surface of envelopes, sound absorption coefficient of materials used for the construction of the envelopes, geometry of rooms or the distribution of sound absorbing materials. The arrangement of sound absorbing materials in rooms has an impact on the dispersion of acoustic field, yet theoretical calculation models do not take into account this impact. According to these models, regardless of the arrangement of sound absorbing materials, the reverberation time in a room will remain unchanged. The present paper investigates the above problem by means of computer simulations. For the needs of the simulation, three rooms with different dimensions were adopted, i.e. type 'p' - a cuboidal room with a square base, type 'd' - a cuboidal room (with one side of the 'p' room lengthened), type 'w' - a cuboidal room (with the height of the room lengthened 'p'). During the simulation, the way of acoustic field dispersion was being changed and its influence on the reverberation time in the rooms was being determined. The authors investigated two situations. The first one involved a non-dampened room, in which the sound absorbing material was being arranged differently. The second one involved a welldampened room, and the dispersion of sound field was analyzed depending on the location of the reflecting material.

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Zhu, Xiangdong, Jian Kang, and Hui Ma. "The Impact of Surface Scattering on Reverberation Time in Differently Shaped Spaces." Applied Sciences 10, no. 14 (July 16, 2020): 4880. http://dx.doi.org/10.3390/app10144880.

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In terms of the overall diffusion sound field, the inherent diffusion state of the space and the scattering coefficient of indoor surfaces work jointly to diffuse sound energy. This study has investigated the impact of surface scattering on reverberation time in differently shaped spaces. First, 10 spaces with the same volume but different shapes were calculated using a computer simulation; Next, two typical spaces were selected to calculate 10 states, in which the volume was multiplied. The calculations results show that the impact of surface scattering on reverberation time in differently shaped spaces follows three laws: in a group of spaces with the same variation pattern, T20 varies with scattering coefficients at a similar rate. In a group of spaces with different variation patterns, there is a difference of more than 5% in the change rate of T20 with scattering coefficients; in imperfect diffusion spaces, decay curves vary in accordance with scattering coefficients. If the scattering coefficients are the same, T20 varies with spatial shapes; when the volume of rectangular spaces and trapezoidal space ranges from 3000 to 30,000 m3, the change rate of T20 is less than 5%. In the present study, spaces were classified by the position combination of shape surfaces. On this basis, we proposed and then graded the concept of “morphology diffusivity”.

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Andersen, Jørgen Bach, Kin Lien Chee, Martin Jacob, Gert Frølund Pedersen, and Thomas Kurner. "Reverberation and Absorption in an Aircraft Cabin With the Impact of Passengers." IEEE Transactions on Antennas and Propagation 60, no. 5 (May 2012): 2472–80. http://dx.doi.org/10.1109/tap.2012.2189700.

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Catalina, Tiberiu, Alexandra Ene, and Andreea Biro. "Visual and acoustic performance of shading devices – real scale laboratory measurements." E3S Web of Conferences 111 (2019): 06072. http://dx.doi.org/10.1051/e3sconf/201911106072.

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There are several physical parameters that are taken into consideration when determining the level of agreeability of an enclosed space. For instance, when choosing the louvers for a room there are a multitude of criteria that might be considered such as colour, material or the degree of opacity. However, these apparently small fixtures may have a significant impact also on other apparently unimportant factors like the sound pressure level and the reverberation time. This paper aims to present different types of devices used to control the way daylight enters a room, from both the illuminance level and the acoustical point of view. During the experimental campaign, five of the most common types of louvers were examined regarding their main role of blocking the light and moreover their influence on the reverberation time and sound pressure level in the analysed chamber.

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Ljunggren, Fredrik, Christian Simmons, and Maria Pettersson. "Uncertainty of in situ low frequency reverberation time measurements from 20 Hz – An empirical study; Part II: Impulse response method." Noise Control Engineering Journal 70, no. 3 (May 1, 2022): 298–308. http://dx.doi.org/10.3397/1/377024.

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An important part of evaluating impact sound insulation is to measure the reverberation time in the receiving room. The increasing trend of using wooden structures for residential buildings has made it increasingly important to have control of the measurement procedure at low frequencies. The present ISO standards do not give any specific guidelines for how to deal with frequencies below 50 Hz. It cannot be taken for granted that the present guidelines developed for higher frequencies are also appropriate for lower frequencies. This paper includes an empirical study of the spatial variation of reverberation time, measured from 20 Hz in two different rooms, with about 100 microphone positions in each room. The results from two alternative methods are compared, based upon the impulse response and the interrupted noise respectively. The accuracy of an intended normal measurement procedure is estimated with respect to the number of microphone positions.

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Ryden, Nils, Unn Dahlen, Per Lindh, and Andreas Jakobsson. "Impact non-linear reverberation spectroscopy applied to non-destructive testing of building materials." Journal of the Acoustical Society of America 140, no. 4 (October 2016): 3327. http://dx.doi.org/10.1121/1.4970601.

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Yeon, Jun Oh, Hye Kyung Shin, Kwan Seop Yang, and Kyoung Woo Kim. "Evaluation of Reduction Performance of Floor Impact Sound on Floor Covering in the Reverberation Chamber." Applied Mechanics and Materials 851 (August 2016): 685–89. http://dx.doi.org/10.4028/www.scientific.net/amm.851.685.

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In order to reduce floor impact sound in apartment houses, 30 types of floor coverings were chosen to evaluate a performance of reduction in impact sound in the reverberation chamber. In the test of performance of reduction in impact sound using bang machine, a performance of impact sound reduction can be ensured at a low frequency band of 63 Hz and 100 Hz. However, impact sound was amplified at a band of 80 Hz and 125 Hz except for some floor coverings. In the test of performance of reduction in impact sound using a rubber ball drop at a height of 100 cm, a performance of reduction in impact sound was improved from a band of 50 Hz up to 400 Hz. In the test of rubber ball drop at a height of 40 cm, which was similar to the impact of children's running, a performance of reduction in impact sound was improved from a band of 80 Hz and 160 Hz up to 400 Hz.

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Holland, Charles W., and Peter Nielsen. "Ocean acoustic boundary characterization multi-national experiments." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A138. http://dx.doi.org/10.1121/10.0010907.

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The condition of the sea surface and seabed boundaries of the ocean often significantly affect the characteristics of acoustic signal propagation, reverberation and noise particularly in shallow water. A series of collaborative experiments were conducted from 2000 to 2009 to better understand the impact of ocean boundary characteristics on ocean acoustic signals in the frequency range of 100 – 5000 Hz. Acoustic measurements included long-range (waveguide) propagation, reverberation, and clutter as well as measurements of local boundary reflection and scattering. These were supported by oceanographic, geophysical and geologic measurements. Experimental locations included the Tyrrhenian Sea, Straits of Sicily, the New Jersey shelf, and the Scotian shelf with collaborators from NATO-STO CMRE and national laboratories and institutions from Italy, Canada, France, and the US. This talk will provide an overview of some of the main results from these experiments. [Research sponsored by CMRE(NATO), ONR(US), NUWC(US), INGV(IT), SHOM(FR), DRDC(CA), Italian Navy(IT).]

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Gheller, Flavia, Elisa Lovo, Athena Arsie, and Roberto Bovo. "Classroom acoustics: Listening problems in children." Building Acoustics 27, no. 1 (November 14, 2019): 47–59. http://dx.doi.org/10.1177/1351010x19886035.

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The acoustic quality of classrooms is crucial for children’s listening skills and consequently for their learning. Listening abilities in kids are still developing, and an environment with inadequate acoustic characteristics may create additional problems in speech perception and phonetic recognition. Background noise or reverberation may cause auditory processing problems and greater cognitive effort. There are also other elements which can make difficulty in listening and understanding in noisy environments an even more serious problem, such as learning disabilities, mild to severe hearing loss or bilingualism. Therefore, it is important to improve the acoustic quality of the classrooms, taking into account the specific needs of children in terms of signal-to-noise ratio and reverberation time, in order to ensure a proper quality of listening. The aim of this work is to analyse, through the review of previous studies, the impact that the acoustic of classrooms has on children’s listening skills and learning activities.

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Korista, K. T., and M. R. Goad. "Quantifying the impact of variable BLR diffuse continuum contributions on measured continuum interband delays." Monthly Notices of the Royal Astronomical Society 489, no. 4 (August 23, 2019): 5284–300. http://dx.doi.org/10.1093/mnras/stz2330.

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ABSTRACT We investigate the contribution of reprocessed continuum emission (1000–10 000 Å) originating in broad-line region (BLR) gas, the diffuse continuum (DC), to the wavelength-dependent continuum delays measured in AGN disc reverberation mapping experiments. Assuming a spherical BLR geometry, we adopt a Local Optimally emitting Cloud (LOC) model for the BLR that approximately reproduces the broad emission-line strengths of the strongest UV lines (Ly α and C iv) in NGC 5548. Within this LOC framework, we explore how assumptions about the gas hydrogen density and column density distributions influence flux and delay spectra of the DC. We find that: (i) models which match well measured emission-line luminosities and time delays also produce a significant DC component, (ii) increased $\rm {\mathit{ n}_H}$ and/or $\rm {\mathit{ N}_H}$, particularly at smaller BLR radii, result in larger DC luminosities and reduced DC delays, (iii) in a given continuum band the relative importance of the DC component to the measured interband delays is proportional (though not 1:1) to its fractional contribution to the total light in that band, (iv) the measured DC delays and DC variability amplitude depend also on the variability amplitude and characteristic variability time-scale of the driving continuum, (v) the DC radial surface emissivity distributions F(r) approximate power laws in radius with indices close to −2 (≈1:1 response to variations in the driving continuum flux), thus their physics is relatively simple and less sensitive to the unknown geometry and uncertainties in radiative transfer. Finally, we provide a simple recipe for estimating the DC contribution in disc reverberation mapping experiments.

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Czyż, Anna, and Magdalena Ciechowska. "AUDITORY SYSTEM AIDING DEVICES AND SCHOOL ENVIRONMENT." Educational Discourse: collection of scientific papers, no. 9(11-12) (December 27, 2018): 57–68. http://dx.doi.org/10.33930/ed.2018.5007.9(11-12)-5.

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The paper deals with the problem of hearing loss in the context of condition of society and statistics determining the need for a discussion regarding the school functioning hard of hearing people. The conditions of the acoustic environment were analyzed, including the impact of: noise, reverberation, volume and absorbency of school rooms, on the communication process. Means of modern hearing devices have been analyzed in context of the speech perception supporting.

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Cammin, Christoph, Dmytro Krush, Dirk Krueger, and Gerd Scholl. "IO-Link Wireless Sensitivity Testing Methods in Reverberation Chambers." Electronics 11, no. 17 (September 3, 2022): 2775. http://dx.doi.org/10.3390/electronics11172775.

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Communication reliability is a challenging requirement, which implies the need for over-the-air (OTA) testing. Reverberation chambers (RCs) are widely used for OTA tests in various fields. Due to their properties, such as inherent radio channel emulation or the arbitrary orientation of the equipment under test (EUT) in the test volume, they can be used as advantageous test environments for wireless products in the field of industrial manufacturing automation, such as for the IO-Link Wireless (IOLW) standard. In this paper, the different OTA sensitivity test procedures total isotropic sensitivity (TIS), average fading sensitivity (AFS) and mean channel packet error (MCPE) method, which is based on the fundamental channel model of the wireless standard, are described and evaluated in various variants. A core aspect of the proposal is the impact of the possible use of frequency hopping of the wireless equipment under test. The respective advantages and disadvantages are shown. Overall, TIS proves to be a suitable alternative for IOLW OTA sensitivity testing.

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Poutanen, Juri. "Impact of reverberation in flared accretion discs on temporal characteristics of X-ray binaries." Monthly Notices of the Royal Astronomical Society 332, no. 2 (May 2002): 257–70. http://dx.doi.org/10.1046/j.1365-8711.2002.05272.x.

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Koumura, Takuya, and Shigeto Furukawa. "Do Speech Contexts Induce Constancy of Material Perception Based on Impact Sound Under Reverberation?" Acta Acustica united with Acustica 104, no. 5 (September 1, 2018): 796–99. http://dx.doi.org/10.3813/aaa.919226.

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Tavares, J. León, V. Chavushyan, A. Lobanov, E. Valtaoja, and T. G. Arshakian. "The link between broad emission line fluctuations and non-thermal emission from the inner AGN jet." Proceedings of the International Astronomical Union 10, S313 (September 2014): 43–47. http://dx.doi.org/10.1017/s1743921315001842.

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AbstractAGN reverberate when the broad emission lines respond to changes of the ionizing thermal continuum emission. Reverberation measurements have been commonly used to estimate the size of the broad-line region (BLR) and the mass of the central black hole. However, reverberation mapping studies have been mostly performed on radio-quiet sources where the contribution of the jet can be neglected. In radio-loud AGN, jets and outflows may affect substantially the relation observed between the ionizing continuum and the line emission. To investigate this relation, we have conducted a series of multi-wavelength studies of radio-loud AGN, combining optical spectral line monitoring with regular VLBI observations. Our results suggest that at least a fraction of the broad-line emitting material can be located in a sub-relativistic outflow ionized by non-thermal continuum emission generated in the jet at large distances (> 1 pc) from the central engine of AGN. This finding may have a strong impact on black hole mass estimates based on measured widths of the broad emission lines and on the gamma-ray emission mechanisms.

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Zhang, Yong Xiang, Bo Liang, Jun Li, and Wei Ke. "Blind Source Separation for Impact Force Induced by Piston Slaps in Diesel Engines." Advanced Materials Research 681 (April 2013): 93–98. http://dx.doi.org/10.4028/www.scientific.net/amr.681.93.

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The diesel engine vibration induced by piston impact force (also known as slaps) presents us very important information about piston-and-cylinder clearance and engine performance. However it is notorious difficult formaking an accurate measurement for the piston slaps due to the enormous interferences, reverberation, and complicated vibration responses. This paper presents an application of blind source separation technique to solve the problem. The method is based on one novel algorithm which uses blind source de-convolution algorithm. It can overcome the conventional blind source separation calculation drawbacks like local minimization value problems occurred with the fixed step response algorithm.The simulation and experiment results have indicated it can recover the corrupted signals and obtain the accurate piston slap signals at the measurement point.

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Shin, Hyunho, Sanghoon Kim, and Jong-Bong Kim. "Stress Transfer Mechanism of Flange in Split Hopkinson Tension Bar." Applied Sciences 10, no. 21 (October 28, 2020): 7601. http://dx.doi.org/10.3390/app10217601.

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To reveal the stress transfer mechanism of the flange in a split Hopkinson tension bar, explicit finite element analyses of the impact of the hollow striker on the flange were performed across a range of flange lengths. The tensile stress profiles monitored at the strain gauge position of the incident bar are interpreted on a qualitative basis using three types of stress waves: bar (B) waves, flange (F) waves, and a series of reverberation (Rn) waves. When the flange length (Lf) is long (i.e., Lf > Ls, where Ls is the striker length), the B wave and first reverberation wave (R1) are fully separated in the time axis. When the flange length is intermediate (~Db < Lf < Ls, where Db is the bar diameter), the B and F waves are partially superposed; the F wave is delayed, then followed by a series of Rn waves after the superposition period. When the flange length is short (Lf < ~Db), the B and F waves are practically fully superposed and form a pseudo-one-step pulse, indicating the necessity of a short flange length to achieve a neat tensile pulse. The magnitudes and periods of the monitored pulses are consistent with the analysis results using the one-dimensional impact theory, including a recently formulated equation for impact-induced stress when the areas of the striker and bar are different, equations for the reflection/transmission ratios of a stress wave, and an equation for pulse duration time. This observation verifies the flange length-dependent stress transfer mechanism on a quantitative basis.

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Felis, Józef, Artur Flach, and Tadeusz Kamisiński. "Testing of a Device for Positioning Measuring Microphones in Anechoic and Reverberation Chambers." Archives of Acoustics 37, no. 2 (June 29, 2012): 245–50. http://dx.doi.org/10.2478/v10168-012-0032-5.

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AbstractThis paper presents a mechanical positioning system for a measuring microphone designed for acoustic studies in anechoic and reverberation chambers at the Department of Mechanics and Vibroacoustics, AGH. The results are discussed in the context of mechanical positioning and its impact on the outcome of the execution of individual measurement procedures. Moreover, areas for research were identified and solution concepts shown for further development of the automation of acoustic measurements in different research rooms in order to reduce the human involvement in them.

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Ondrejka, Vojtěch, Tomáš Gergeĺ, Anna Danihelová, Martin Čulík, Dagmara Bednárová, Marián Schwarz, and Miroslav Němec. "THE IMPACT OF ACOUSTIC OF SELECTED SPACES ON PERCUSSION INSTRUMENTS." Akustika, VOLUME 37 (December 15, 2020): 37–85. http://dx.doi.org/10.36336/akustika20203772.

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The results of the investigation of the room acoustic properties influence on the perception of the sound of percussion musical instruments are presented in the paper. At first, the acoustic properties of two rooms were determined without musical instrument. Subsequently, the acoustic properties of the rooms were determined during the presentation of cajon music. On the base of reverberation time (EDT, T30), Clarity C80, Definition D50 and bass index BI) we can conclude that the room of the Hron cinema is more suitable for musical presentation, but it cannot be considered as ideal one. The Royal Hall of Zvolen Castle has a smaller influence on the sound of a percussion instrument. The influence of room acoustic properties on the resulting sound of the instrument was evaluated only on the base of results obtained with using the objective methods by the physical quantities measurement. Finally, the design of these rooms modification is presented to achieve a better sound quality of percussion instruments.

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Venkataraman, Rajesh, Jeethu M. Mathai, Linu Thomas, and Mathew James. "IMPACT OF DEMOGRAPHIC VARIABLES ON BLOOD PRESSURE AND GLYCEMIC CONTROL." Asian Journal of Pharmaceutical and Clinical Research 11, no. 10 (October 7, 2018): 179. http://dx.doi.org/10.22159/ajpcr.2018.v11i10.25599.

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Objective: This study was designed to analyse the impact of demographic variables on blood pressure and glycaemic levels in patients with diabetes and hypertension.Methods: A community-based prospective observational study was conducted over a span of six months in the rural villages of Nagamangala Taluk, Mandya Dist, Karnataka.Results: Among 320 subjects, 285 patients had been enrolled in the study. The demographic variable such as age was found to be significantly correlated with random blood sugar and blood pressure level. Whereas gender was significantly correlated to the RBS level, while negatively correlated to blood pressure level. Even though the economic status was not significant, educational status was significant to both RBS and blood pressure level.Conclusion: This inquest portrayed that educational stature brings out an immense reverberation on glycemic and blood pressure control apart from other demographic variables. So this study confers an insight that, strategies for educating patients especially in rural areas thereby making them aware of long-term complications leads to augment overall health outcome.

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Kanka, Simon, Luca Fredianelli, Francesco Artuso, Francesco Fidecaro, and Gaetano Licitra. "Evaluation of Acoustic Comfort and Sound Energy Transmission in a Yacht." Energies 16, no. 2 (January 10, 2023): 808. http://dx.doi.org/10.3390/en16020808.

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After being neglected for a long time, in the last years, ships have been recognized and studied as sound emitters. The sound energy they generate impacts the outside, but it can also affect the indoor quality of life if the environments are not properly designed. In fact, acoustic comfort plays a pivotal role, particularly in recreational crafts. In the present work, room acoustics and acoustic camera measurements were performed, inside a 50 m length overall yacht, chosen as a case study in order to evaluate the acoustic comfort. The Italian classification procedure UNI 11367:2010 for buildings was applied, and results have been compared to other international comfort classes. However, all of these are based on prescription for standard buildings, and the present work highlights that they do not account for the effective ship’s acoustic issues: sound energy transfer from impacts over ceilings and sound energy leakage. While attention of shipbuilders in acoustic comfort is shown in the measured good reverberation times, the acoustic camera revealed sound energy leakages corresponding to hidden escape ways that have been poorly insulated. This compromises the standardized sound difference between contiguous compartments and also the thermal insulation, as leakage involves air passages. The present work attempts to evolve the classification procedure by also including, for the first time, the reverberation time, but future studies focused on finding correct standardized impact level noise for ship cases are needed. In fact, their values were very high and not comparable with those measured in actual buildings and for which reference values have been designed.

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Araújo, Francisco Jonathan de Oliveira, Ligia Samara Abrantes de Lima, Pedro Ivo Martins Cidade, Camila Bezerra Nobre, and Modesto Leite Rolim Neto. "Impact Of Sars-Cov-2 And Its Reverberation In Global Higher Education And Mental Health." Psychiatry Research 288 (June 2020): 112977. http://dx.doi.org/10.1016/j.psychres.2020.112977.

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Liu, Chunchuan, and Fengming Li. "Impact transient response in lattice sandwich panels under various boundaries using reverberation ray matrix method." Composite Structures 125 (July 2015): 239–46. http://dx.doi.org/10.1016/j.compstruct.2015.01.035.

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Vehovszky, Balázs, István Horváth, Karl Slenczka, Martin Schuster, and Tamás Jakubík. "Vibration Damping Measurement on Car Windshields." Periodica Polytechnica Mechanical Engineering 63, no. 1 (November 13, 2018): 1–6. http://dx.doi.org/10.3311/ppme.11559.

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Knowledge of the damping properties of a windshield is a fundamental element of the acoustical characterization of a car. The measuring method of damping for a windshield is presented in the paper. The damping loss factor – as a basic measure of mechanical damping – was determined experimentally by two means: the reverberation time from impact hammer testing as well as the modal behavior from 3D laser scanning vibrometer measurements. The results proved that the modal shapes have a fundamental effect on the measured damping values.

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Dong, Wayland, John Lo Verde, and Samantha Rawlings. "Sound pressure-based ratings are preferred for evaluation of insitu sound isolation." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A34. http://dx.doi.org/10.1121/10.0010572.

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The International Building Code has recently been revised to explicitly specify the ratings to use for field ( in situ) measurements of airborne and impact sound isolation in residential properties. We review the differences between the various ratings, which (on the surface) are defined by their normalization procedure. Two normalization options are defined in current ASTM and ISO standards: a standard reverberation time of 0.5 s, and a standard amount of absorption of 10m2. It is not always appreciated that the choice of normalization is a choice of the type of measurement being performed. Normalization to a standard reverberation time is based on sound pressure and hence is a measurement of the acoustic isolation between spaces, while normalization to a standard amount of absorption is based on apparent sound power and hence is a measurement of the performance of the separating assembly. It is sometimes assumed the sound power-based ratings are representative of the sound isolation experienced by occupants, but they often provide an inaccurate assessment of the resultant isolation. Analysis and examples are presented, and it is demonstrated that the sound pressure-based ratings are preferred.

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Redonnet, Stéphane. "Theoretical Study of the Acoustic Installation Effects in Closed-Vein Wind Tunnels for the Experimental Characterization of Trailing Edge Noise." Applied Sciences 11, no. 20 (October 18, 2021): 9718. http://dx.doi.org/10.3390/app11209718.

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This study focuses on the acoustic installation effects that may occur during typical aeroacoustic experiments when the latter are conducted in a closed-vein wind tunnel. More precisely, in regard to the specific problem of airfoil trailing edge noise, an analytical model is derived, which allows predicting the wall-induced reverberation effects that such a noise shall be subjected to, when radiating within a closed-vein, hard-wall, wind tunnel. These effects are then assessed through a parametric investigation so as to characterize their impact on in situ acoustic measurements that would be performed using flush-mounted microphones located on the vein’s walls. From a phenomenological perspective, the study highlights how important the reverberation effects by the vein can be. In particular, results reveal how their impact on the noise measurements may greatly vary, depending on the trailing edge noise source location (i.e., the airfoil incidence) and, to a lesser extent, its frequency. The outcomes allow identifying these locations where the installation effects are least, i.e., where to better position a flush-mounted microphone, should in situ noise measurements be conducted. From a methodological viewpoint, the study showcases how the proposed formalism could constitute a simple albeit useful diagnosis tool for mitigating the experimental biases weighing on airfoil trailing edge noise tests to be conducted within closed-vein facilities, whether this would be done a priori by flush-mounting the microphone(s) where these biases are minimal or a posteriori by de-biasing the noise measurements accordingly.

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Herstein, Peter D., Bernard F. Cole, Kerry E. Brown, Eugene M. Podeszwa, and David G. Browning. "The impact of backscatter angular dependency on reverberation levels in shallow water under downward refracting conditions." Journal of the Acoustical Society of America 93, no. 4 (April 1993): 2300. http://dx.doi.org/10.1121/1.406466.

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Choi, Jung-Hwan, Jee-Hoon Lee, and Seong-Ook Park. "Characterizing the Impact of Moving Mode-Stirrers on the Doppler Spread Spectrum in a Reverberation Chamber." IEEE Antennas and Wireless Propagation Letters 9 (2010): 375–78. http://dx.doi.org/10.1109/lawp.2010.2049331.

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Wróbel, Jakub, and Damian Pietrusiak. "Noise Source Identification in Training Facilities and Gyms." Applied Sciences 12, no. 1 (December 22, 2021): 54. http://dx.doi.org/10.3390/app12010054.

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This paper deals with noise problems in industrial sites adapted for commercial training venues. The room acoustics of such an object were analyzed in the scope of the reverberation time and potential acoustic adaptation measures are indicated. Identification and classification of noise sources in training facilities and gyms was carried out based on the acoustic measurements. The influence of rubber padding on impact and noise reduction was investigated in the case of chosen noise-intensive exercise activities performed in a previously described acoustic environment. Potential noise reduction measures are proposed in the form of excitation reduction, vibration isolation, and room acoustics adaptation.

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Guo, Qian, Xinglin Tong, Cui Zhang, Chengwei Deng, Baolin Zhang, Qiao Xiong, and Chaoran Zhou. "Method for Detecting the Inside of Coke Drum Using Acoustic Signals." Journal of Sensors 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/2816461.

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A distance and acoustic intensity reverberation (DAIR) physical model is developed that can be successfully applied to the signal processing of the hydraulic decoking process online monitoring. In this model, the transmission characteristics of acoustic signals generated by a moving sound source in a dynamic confined space are first analyzed using data recursion and correction according to the coordinate continuity in adjacent area and adjacent time. The results show that the nondetection zone of acoustic signals generated directly by the impact of water is eliminated, and the surface distribution of coke in the drum can be mapped in real time.

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Prodi, Nicola, and Matteo Marsilo. "On the Effect of Domed Ceiling in Worship Spaces: A Scale Model Study of a Mosque." Building Acoustics 10, no. 2 (June 2003): 117–33. http://dx.doi.org/10.1260/135101003768965979.

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Though the importance of domes in worship buildings has been recognised since ancient times, their acoustic effects have not been entirely addressed by acoustics researchers. In addition to the known detrimental effects of late reflections and echoes, more complicated behaviour can be expected as a result of the coupling of the dome volume to the rest of the room. This investigation is focused on the impact of a dome on reverberation time. This is done using a scale model study of a typical mosque. The results show how the parameter is affected and indicate how the phenomenon might be quantified.

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Emetere, Moses Eterigho. "A modified approach to estimating thermodynamic impact on buildings." Journal of Engineering, Design and Technology 17, no. 1 (February 4, 2019): 115–35. http://dx.doi.org/10.1108/jedt-04-2017-0028.

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Purpose Managing the urban housing plan of a very fast-growing city may be difficult if the scientific input, i.e. thermodynamic architecture and the climate change challenges, is not factored into its initial framework. Recent building plan in some parts of a growing city located in a developing country was adopted for the purpose of this research. The purpose of this study is to investigate the impact of poor urban planning on humans. Design/methodology/approach The reverberation time analysis was carried using the Ecotect software. In total, 15-year surface temperature data were obtained (1999-2013) from the Global Land Data Assimilation System. Thermal distributions were calculated using beta probability and Gaussian distribution. Also, the parametric study of the solar constant was accomplished using possible mathematical outcomes. Findings It was discovered that irrespective of the fabrics of building, air properties and materials within a building, the total heat and sound absorptions are high for the life form. Necessary recommendations were made for further study. Research limitations/implications Only the outdoor impact was calculated. Practical implications There should be more proactive measures by the urban planning authorities. Social implications There would be wide spread of diseases and very low thermal comfort. Originality/value This paper illustrates on the most ignored parameter in environmental architecture.

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Journal articles on the topic 'Reverberation Impact'

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