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1
Huang, Yang, Sipei Zhao e Jing Lu. "Acoustic contrast control with a sound intensity constraint for personal sound systems". Journal of the Acoustical Society of America 155, n. 2 (1 febbraio 2024): 879–90. http://dx.doi.org/10.1121/10.0024617.
Testo completoAbstract (sommario):
Personal sound systems have received significant research interest in the past two decades due to their promising applications in a variety of scenarios. Various methods have been proposed to generate personal sound zones, most of which are based on sound pressure manipulation in both the acoustically bright and dark zones. Since sound intensity is closely related to human perception of sound localization, this paper proposes an acoustic contrast control method with a sound intensity constraint to increase the spatial planarity in the bright zone. In the proposed method, the sound intensity in the bright zone is projected to a specific direction while the sound pressure level in the dark zone is minimized. Simulations and experiments are carried out to compare the proposed method with the existing planarity control and pressure matching methods in terms of acoustic contrast, array effort, and planarity. The results demonstrate that the proposed method improves the planarity in the bright zone compared to existing planarity control method, while exhibitig a higher acoustic contrast and a lower array effort than the pressure matching method.
2
Lee, Hsiao Mun, Heow Pueh Lee e Zhiyang Liu. "Acoustical Environment Studies in the Modern Urban University Campuses". Acoustics 4, n. 1 (7 gennaio 2022): 14–25. http://dx.doi.org/10.3390/acoustics4010002.
Testo completoAbstract (sommario):
The quality of the acoustic environments at Xi’an Jiatong-Liverpool University (XJTLU) and Soochow University (Dushuhu Campus, SUDC) in Suzhou City were investigated in the present work through real-time noise level measurements and questionnaire surveys. Before commencing the measurements and surveys, these two campuses’ sound sources were summarized and classified into four categories through on-site observation: human-made, machinery, living creatures, and natural physical sounds. For the zones near the main traffic road, with a high volume of crowds and surrounded by a park, sound from road vehicles, humans talking, and birds/insects were selected by the interviewees as the major sound sources, respectively. Only zone 3 (near to a park) at XJTLU could be classified as A zone (noise level < 55 dBA) with an excellent quality acoustical environment. All other zones had either good or average quality acoustical environments, except zone 1 (near to main traffic road) at XJTLU, with a fair-quality acoustical environment.
3
Jeong, Jeong-Ho. "Prediction and Evaluation of Emergency Broadcasting Sound and Speech Intelligibility for Safety Zones in High-rise Buildings". Fire Science and Engineering 34, n. 6 (31 dicembre 2020): 37–43. http://dx.doi.org/10.7731/kifse.91d2fd5b.
Testo completoAbstract (sommario):
As construction of high-rise buildings is increasing, the installation of a fire safety zone for the safe evacuation of residents has become mandatory. Even for building complexes with an underground connection between 30 and 49 stories, a fire safety zone must be installed when the residential density exceeds 1.5 people per square meter. In the fire safety zone, an automatic fire detection system and a system to assist radio communication must be installed. In addition, an emergency broadcasting system must be installed to announce the fire situation and to guide the safe evacuation of the residents. The fire safety zone was constructed with non-combustible material to minimize flames or smoke and was furnished to maintain a very low fire load. However, non-combustible materials have very low sound absorption characteristics; therefore, they usually reflect the sound energy into the spaces. In spaces consisting of sound reflective materials, the emergency broadcasting sounds reverberated, making it difficult to understand the meaning of the broadcasted sound. In this study, the room acoustics characteristics for fire safety zones in a high-rise building, represented as reverberation time and speech transmission index, were predicted using a certified room acoustics simulation method and evaluation of speech intelligibility. As a result of predicting the acoustic characteristics of the safety zone, it was found that the space had quite long reverberation and speech intelligibility was low, making it difficult to clearly transmit the emergency broadcast sound. When a safety zone was set up in a part of the machinery room, it was confirmed that it was difficult to clearly transmit the emergency broadcast sound, even when the background noise level was louder than 70 dB(A). To deliver a clear emergency broadcast sound in the safety zone, it is necessary to use inorganic sound-absorbing materials and to properly block noise in the machine room. In addition, it is necessary to establish guidelines for regulation of the speech transmission index for emergency broadcasting systems.
4
Wen, Xin, Haijun Wu, Yilong Fan e Weikang Jiang. "A multizone sound field reproduction method based on modal domain analysis". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, n. 5 (30 novembre 2023): 3916–21. http://dx.doi.org/10.3397/in_2023_0559.
Testo completoAbstract (sommario):
Multizone sound field reproduction for synthesizing desired sound fields over multiple spatial zones has been widely studied. In the traditional multizone sound field reproduction modal domain method, the final loudspeaker weights required to reproduce the desired sound field are obtained by translating the optimal equivalent global modal domain coefficients, which is susceptible to the characteristics and location of the loudspeakers and reduces the reproduction performance. This paper investigates a multizone sound field reproduction in modal domain for directly obtaining the reproducing loudspeaker weights. The optimization model is formulated to the objective of reproducing a desired sound field within the bright zone and with constraints on acoustic energy in the dark zone. The loudspeaker weights for reproducing the desired sound field are solved by the CVX toolbox. The numerical simulation results indicate that the proposed method is superior to the acoustic contrast control method and the mode matching method in terms of the accuracy of the reproduction desired sound field in the bright zone and the acoustic contrast between the bright and dark zones.
5
Kim, Deliya, Eldad Jitzhak Avital e Touvia Miloh. "Sound Scattering and Its Reduction by a Janus Sphere Type". Advances in Acoustics and Vibration 2014 (18 settembre 2014): 1–11. http://dx.doi.org/10.1155/2014/392138.
Testo completoAbstract (sommario):
Sound scattering by a Janus sphere type is considered. The sphere has two surface zones: a soft surface of zero acoustic impedance and a hard surface of infinite acoustic impedance. The zones are arranged such that axisymmetry of the sound field is preserved. The equivalent source method is used to compute the sound field. It is shown that, by varying the sizes of the soft and hard zones on the sphere, a significant reduction can be achieved in the scattered acoustic power and upstream directivity when the sphere is near a free surface and its soft zone faces the incoming wave and vice versa for a hard ground. In both cases the size of the sphere’s hard zone is much larger than that of its soft zone. The boundary location between the two zones coincides with the location of a zero pressure line of the incoming standing sound wave, thus masking the sphere within the sound field reflected by the free surface or the hard ground. The reduction in the scattered acoustic power diminishes when the sphere is placed in free space. Variations of the scattered acoustic power and directivity with the sound frequency are also given and discussed.
6
Erbe, Christine, David Peel, Joshua N. Smith e Renee P. Schoeman. "Marine Acoustic Zones of Australia". Journal of Marine Science and Engineering 9, n. 3 (19 marzo 2021): 340. http://dx.doi.org/10.3390/jmse9030340.
Testo completoAbstract (sommario):
Underwater sound is modelled and mapped for purposes ranging from localised environmental impact assessments of individual offshore developments to large-scale marine spatial planning. As the area to be modelled increases, so does the computational effort. The effort is more easily handled if broken down into smaller regions that could be modelled separately and their results merged. The goal of our study was to split the Australian maritime Exclusive Economic Zone (EEZ) into a set of smaller acoustic zones, whereby each zone is characterised by a set of environmental parameters that vary more across than within zones. The environmental parameters chosen reflect the hydroacoustic (e.g., water column sound speed profile), geoacoustic (e.g., sound speeds and absorption coefficients for compressional and shear waves), and bathymetric (i.e., seafloor depth and slope) parameters that directly affect the way in which sound propagates. We present a multivariate Gaussian mixture model, modified to handle input vectors (sound speed profiles) of variable length, and fitted by an expectation-maximization algorithm, that clustered the environmental parameters into 20 maritime acoustic zones corresponding to 28 geographically separated locations. Mean zone parameters and shape files are available for download. The zones may be used to map, for example, underwater sound from commercial shipping within the entire Australian EEZ.
7
Merzenich, Michael. "Seeing in the sound zone". Nature 404, n. 6780 (aprile 2000): 820–21. http://dx.doi.org/10.1038/35009174.
Testo completo
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Westervelt, Peter J. "Scattering of sound by sound within the interaction zone". Journal of the Acoustical Society of America 96, n. 5 (novembre 1994): 3320. http://dx.doi.org/10.1121/1.410764.
Testo completo
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Du, Bokai, e Qun Yan. "Multizone sound field reproduction based on equivalent source decomposition". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, n. 8 (30 novembre 2023): 880–89. http://dx.doi.org/10.3397/in_2023_0140.
Testo completoAbstract (sommario):
Multizone sound field reproduction attempts to recreate a desired sound field on the bright zone and reduce sound field energy on the dark zone. Conventional pressure-matching based multizone reproduction method is only able to control sound pressures at limited number of measurement points on the bright zones which are equal to target sound field recording points number. The reproduction performance is strongly affected by the number of recording points. In this paper, a reproduction method based on the sparse plane wave decomposition method is proposed to improve the reproduction performance when the target sound field is generated by one or a small number of sources. The recorded target sound field is decomposed into a group of plane waves. Loudspeaker weights are calculated as a summation precalculated corresponding plane waves weights. A simulation is conducted in a room to verify the performance of the proposed method. Compared with the conventional method, the proposed method achieves better sound field reproduction accuracy on the bright zone and similar acoustic contrast performance.
10
Lin, Yi-Wei, e Gee-Pinn James Too. "A Parametric Study of Sound Focusing in Shallow Water by Using Acoustic Contrast Control". Journal of Computational Acoustics 22, n. 04 (18 settembre 2014): 1450012. http://dx.doi.org/10.1142/s0218396x1450012x.
Testo completoAbstract (sommario):
Acoustic contrast control is a sound focusing technique applied to personal audio system devices to provide the optimal sound contrast for increasing or decreasing the potential sound energy of a specific area. In this study, acoustic contrast control was developed for sound focusing in shallow water. The advantage of this technique is the establishment of two zones: a bright zone around the user and a dark zone for other regions. In the acoustic contrast control process, computational ocean acoustics are used to calculate the Green's function between the source point and the field point. The effects of environmental parameters, which comprised the number of control sources, transmission frequency, control distances between sources and control zone of a geometric location were simulated. The results show that acoustic contrast control is an effective approach for sound focusing in shallow water that can increase the potential sound energy of a specific area. Employing this technique can also enhance underwater communications by using frequency-shift keying modulation for cross-talking applications.
11
Rui, Guo, Lei Liu, Sheng Zhen-Xin e Song Pu. "A three-dimensional bistatic reverberation model of underwater explosion by interface scattering at variable sound speeds". Journal of Low Frequency Noise, Vibration and Active Control 38, n. 2 (12 dicembre 2018): 427–40. http://dx.doi.org/10.1177/1461348418816458.
Testo completoAbstract (sommario):
Underwater reverberation is a main limitation of the sonar performance and thereby the reverberation level estimation becomes crucial. In this study, based on the Lambert law and ray theory, a model for predicting 3D bistatic reverberation performance by interface scattering at linear sound speed profile is established and then verified through the underwater explosion experiments. The Influences of source and receiver positions, and relative sound speed gradient on reverberation performance are further investigated. The results indicate that: (1) the proposed model can predict the short-range mean reverberation level effectively, with the deviation 2–4 dB and describe the whole reverberation level distribution in some details; (2) at the early reverberation phase, the interference effects between the interface scattering sounds are considerable and a dominating interface exists; the counterbalance between the losses by scattering, spreading and medium absorption results in the local high-intensity zones close to corresponding interfaces, respectively; (3) as the sound source moves towards some interface, associated local high-intensity zone gradually expands, while the other one shrinks; if the sound speed approaches are constant, an extra local high-intensity zone will appear between the previous two but with a lower magnitude.
12
Okamoto, Takuma. "Multilingual sound sopt synthesis systems". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, n. 3 (30 novembre 2023): 5861–65. http://dx.doi.org/10.3397/in_2023_0842.
Testo completoAbstract (sommario):
Localized sound zone synthesis, which can generate acoustically bright and dark zones using loudspeakers, is gaining attention as one of important acoustic communication techniques. By superposing multiple localized sound zones, multiple sound spot synthesis can simultaneously deriver different sound signals at different zones using a loudspeaker array. Additionally, it can be implemented as a user interface for real-time speech translation by combining multilingual speech synthesis technology. This paper introduces multilingual sound spot synthesis systems based on spatial Fourier transform implemented by using compact circular array of 16 loudspeakers and linear array of 64 loudspeakers combined with multilingual neural speech synthesis.
13
Qiao, Yue, Léo Guadagnin e Edgar Choueiri. "Isolation performance metrics for personal sound zone reproduction systems". JASA Express Letters 2, n. 10 (ottobre 2022): 104801. http://dx.doi.org/10.1121/10.0014604.
Testo completoAbstract (sommario):
Two isolation performance metrics, inter-zone isolation (IZI) and inter-program isolation (IPI), are introduced for evaluating personal sound zone (PSZ) systems. Compared to the commonly used acoustic contrast metric, IZI and IPI are generalized for multichannel audio and quantify the isolation of sound zones and of audio programs, respectively. The two metrics are shown to be generally non-interchangeable and suitable for different scenarios, such as generating dark zones (IZI) or minimizing audio-on-audio interference (IPI). Furthermore, two examples with free-field simulations are presented and demonstrate the applications of IZI and IPI in evaluating PSZ performance in different rendering modes and PSZ robustness.
14
Li, Ziyang, Shengchun Piao, Minghui Zhang e Lijia Gong. "Influence of Range-Dependent Sound Speed Profile on Position of Convergence Zones". Remote Sensing 14, n. 24 (13 dicembre 2022): 6314. http://dx.doi.org/10.3390/rs14246314.
Testo completoAbstract (sommario):
Based on the Wentze–Kramers–Brillouin approximation, we derive formulae to calculate the position of convergence zones in a range-dependent environment with sound speed profiles varying in linear and ellipsoidal Gaussian eddy cases. Simulation results are provided for the linear and ellipsoidal Gaussian eddy cases. Experiment data are used for calculations considering linearly varying sound speed, and the findings suitably agree with the simulation results. According to the evaluated environment, the influence of the range-dependent sound speed profile on the position of the upper and lower convergence zones for different source depths is analyzed through simulations. The corresponding results show that the influence of the sound speed profile on the position of the upper convergence zone is greater for a shallower source. In contrast, the position of the lower convergence zone for large-depth reception is less affected.
15
Tamariska ; Roni Sugiarto, Livie. "THE DYNAMICS OF SOUNDSCAPE CONNECTION WITH ARCHITECTURAL ELEMENTS ON TERAS CIKAPUNDUNG BANDUNG". Riset Arsitektur (RISA) 2, n. 03 (5 luglio 2018): 249–63. http://dx.doi.org/10.26593/risa.v2i03.2945.249-263.
Testo completoAbstract (sommario):
Abstract- In architecture of public space, the experience of place plays an important role in the making of the good quality of public spaces. The experience of the space is multi-sensory, so architecture should emphasize its attention also on the architectural space approach through auditory experience. The study was conducted to determine the dynamics connection of soundscape experience and Terrace Cikapundung architecture.The research method is qualitative and descriptive analysis. Quantitative measurements are made to complement the qualitative data. The analysis is done through questionnaire distribution, field observation, analysis, and by relating it with the study of theories about public space architecture, soundscape, sacred sounds, sense of place, intention of architecture, and perception theory.In Terrace Cikapundung are found quite a lot of natural sounds, which are considered as sounds that improve the quality of the people spatial experience. The natural sounds that are found there are the sound of birds, wind, and water flow. While the dominant voice heard is the sound of motor vehicle, which is considered as disturbing sound for the audiences in particular “man-made zone” (zone that borders the highway). This indicates that there are some architectural elements that have not been able to work optimally, especially the design of bordering element between the site with the main sound source (Jalan Siliwangi). Furthermore, the concave physical topology and the zonation of “man-made zone” and “natural zone” is well designed, based on the variety characterictic of function, location, and order of architectural elements, that will give us the study and example of spatial making and good experience of place.Through design that concern in the multi-sensory aspects of experience, especially in auditory experience, the experience of space can be felt thoroughly and the quality of a public space can be increased. Key Words: soundscape, architectural element, open public space
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Tamariska ; Roni Sugiarto, Livie. "THE DYNAMICS OF SOUNDSCAPE CONNECTION WITH ARCHITECTURAL ELEMENTS ON TERAS CIKAPUNDUNG BANDUNG". Riset Arsitektur (RISA) 2, n. 03 (5 luglio 2018): 248–63. http://dx.doi.org/10.26593/risa.v2i03.2945.248-263.
Testo completoAbstract (sommario):
Abstract- In architecture of public space, the experience of place plays an important role in the making of the good quality of public spaces. The experience of the space is multi-sensory, so architecture should emphasize its attention also on the architectural space approach through auditory experience. The study was conducted to determine the dynamics connection of soundscape experience and Terrace Cikapundung architecture.The research method is qualitative and descriptive analysis. Quantitative measurements are made to complement the qualitative data. The analysis is done through questionnaire distribution, field observation, analysis, and by relating it with the study of theories about public space architecture, soundscape, sacred sounds, sense of place, intention of architecture, and perception theory.In Terrace Cikapundung are found quite a lot of natural sounds, which are considered as sounds that improve the quality of the people spatial experience. The natural sounds that are found there are the sound of birds, wind, and water flow. While the dominant voice heard is the sound of motor vehicle, which is considered as disturbing sound for the audiences in particular “man-made zone” (zone that borders the highway). This indicates that there are some architectural elements that have not been able to work optimally, especially the design of bordering element between the site with the main sound source (Jalan Siliwangi). Furthermore, the concave physical topology and the zonation of “man-made zone” and “natural zone” is well designed, based on the variety characterictic of function, location, and order of architectural elements, that will give us the study and example of spatial making and good experience of place. Through design that concern in the multi-sensory aspects of experience, especially in auditory experience, the experience of space can be felt thoroughly and the quality of a public space can be increased. Key Words: soundscape, architectural element, open public space
17
Cadavid, José, Martin B. Møller, Søren Bech, Toon van Waterschoot e Jan Østergaard. "Spatial sampling versus acquisition time of room impulse responses for low-frequency sound zones". Journal of the Acoustical Society of America 154, n. 4_supplement (1 ottobre 2023): A164. http://dx.doi.org/10.1121/10.0023140.
Testo completoAbstract (sommario):
Sound zone methods aim to create multiple listening areas within a room, allowing independent playback of different audio content. Achieving this requires a loudspeaker array, multiple microphones per sound zone, and a set of control filters, which design involves the room impulse responses (RIRs) between loudspeakers and microphones. Under certain acoustic conditions, acquiring these RIRs is possible using very short acquisition times. At lower frequencies, longer wavelengths enable spatial sampling of the sound zones with fewer points, reducing the number of microphone positions required and amount of data to process. This study exploits this characteristic to render and evaluate low-frequency sound zones in two real rooms, with few spatial sampling points. We assess the performance by objectively evaluating multiple spatial sampling configurations and RIR acquisition times. Furthermore, we evaluate the system's ability to control sound beyond the sampled regions by assessing the sound field over wider areas. For sound zones roughly the size of a human head, satisfactory performance is achieved in low reverberation conditions with at least two microphones per ear, even for RIR acquisition times as short as 150 μs. Conversely, the performance degradation in highly reflective environments cannot be compensated using additional microphones nor longer acquisition times.
18
Denney, Dennis. "Environmentally Sound Transition-Zone Marine Vibrator". Journal of Petroleum Technology 51, n. 01 (1 gennaio 1999): 73–75. http://dx.doi.org/10.2118/0199-0073-jpt.
Testo completo
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Wang, Ran, Xiaolin Wang, Jingwei Liu e Jun Yang. "Dual-Zone Active Noise Control Algorithm". Applied Sciences 10, n. 1 (18 dicembre 2019): 4. http://dx.doi.org/10.3390/app10010004.
Testo completoAbstract (sommario):
When active noise control (ANC) is applied to acquire a ‘quiet zone’, it may produce an increase in the sound power outside the quiet zone and a change in the primary sound field, which are undesirable in anti-detection and personal audio. To obtain a large noise reduction in the control zone and a small increase of sound power outside the control zone, three wideband ANC algorithms are proposed based on the acoustic contrast control (ACC), least-squares (LS), and least-squares with acoustic contrast control (SFR-ACC) algorithms. With a loudspeaker array as the secondary source, dual-zone ANC with directivity, which realizes noise reduction in one zone without changing the sound power in the other zone, is achieved. Compared with the traditional LS algorithm, the three algorithms proposed in this paper can not only realize that the sound power outside the control zone is increased by less than 1 dB, but also reduce the noise in the control zone by more than 10 dB, which provides a new solution to multi-zone ANC research.
20
Chen, Xiaoyang, Zhuocheng Diao, Siyan He, Guo Zheng e Qingkang Yu. "Amplification Characteristics of Fresnel Zone Plate Acoustic Lens". STEM Fellowship Journal 3, n. 1 (1 febbraio 2017): 15–22. http://dx.doi.org/10.17975/sfj-2017-003.
Testo completoAbstract (sommario):
This paper aims to determine the effects of a Fresnel Zone Plate on the intensity of sound waves upon their interaction. To observe these effects, a prototype Even Fresnel Zone Plate, composed of four concentric rings, was made from an acrylic sheet with the dimensions 60.0cm x n60.0cm x 3.13mm. The exact dimensions of the prototype were calculated using the selected focal length and working frequency in order to optimize for the constructive interference of sound waves. After a sound wave at the selected frequency is produced, a small region of highly amplified sound is formed and studied. It was discovered that the amplification of sound waves is highly dependent on the frequency of sound, as well as the location at which the sound intensity level is measured.
21
ZHAO, Huanqi, Kean CHEN, Liang YAN, Bing ZHOU, Jiangong ZHANG, Jun ZHANG, Yunyun DENG, Han LI e Hao LI. "Suppression and analysis on annoyance of motor vehicle noise using water sound injection". Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 40, n. 3 (giugno 2022): 560–67. http://dx.doi.org/10.1051/jnwpu/20224030560.
Testo completoAbstract (sommario):
Different from the traditional noise control approaches based on sound energy reduction, this study focuses on the annoyance suppression of motor vehicle noise based on audio injection. Firstly, eight motor vehicle noises were selected as the target sounds and three different controllable sounds were used to overlap with different signal-to-noise ratios. Then absolute threshold and combined sound annoyance subjective evaluation experiment were carried out to obtain absolute threshold range and the existence zone of "destructive effect" for combined noise annoyance. Next the influencing factors of the destructive effect are analyzed. The results of the study found that the identifiability of the target sound and the controllable sound is important to the selection of the controllable sound. For most target sounds with high identifiability, the controllable sound with high identifiability and high SNR should be selected. For most target sounds with low identifiability, the controllable sound with low identifiability and low SNR should be selected. Moreover, after the addition of optimal controllable sound, the descend value of the annoyance degree of the target sound with high identifiability is lower than that of the target sound with low identifiability. The results will also provide guidance for the research on audio injection effects, physical mechanisms, the controllable sound selection and optimization design.
22
Zhao, Sipei, e Ian S. Burnett. "Evolutionary array optimization for multizone sound field reproduction". Journal of the Acoustical Society of America 151, n. 4 (aprile 2022): 2791–801. http://dx.doi.org/10.1121/10.0010309.
Testo completoAbstract (sommario):
Multizone sound field reproduction aims to generate personal sound zones in a shared space with multiple loudspeakers. Traditional multizone sound field reproduction methods have focused on optimizing the source strengths given a preset array configuration. Recently, however, various methods have explored optimization of the loudspeaker locations. These can be categorized into sparse regularization and iterative methods with existing studies based on numerical simulations and mostly aiming at single-zone sound field reproduction. In this paper, unique experiments compare the state-of-the-art loudspeaker placement optimization methods by selecting a smaller number of loudspeakers from the candidates uniformly placed along a circle. An evolutionary array optimization scheme is proposed and shown to outperform the best existing methods in terms of mean square error in the bright zone and acoustic contrast between the bright and dark zones at frequencies below 1 kHz. The proposed evolutionary optimization scheme is simple, flexible, and can be extended to broadband optimization and other cost functions.
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Westervelt, Peter J. "Scattering of sound by sound within the interaction zone: Approximate solutions". Journal of the Acoustical Society of America 97, n. 5 (maggio 1995): 3375. http://dx.doi.org/10.1121/1.413007.
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Parnum, Iain M., Adrian Flynn, David M. Donnelly e Michael Clarke. "Underwater acoustic surveys in the eastern Clarion Clipperton Zone". Journal of the Acoustical Society of America 154, n. 4_supplement (1 ottobre 2023): A275. http://dx.doi.org/10.1121/10.0023511.
Testo completoAbstract (sommario):
A drifting, underwater sound recording system was developed and deployed for acoustic surveys of vocalizing marine mammals in the eastern Clarion Clipperton Zone (CCZ), Northern Tropical Pacific. The system was designed to position an Ocean Instruments Sound Trap 500HF recorder and hydrophone at a depth of 450 m. A depressor vane was inserted halfway along the drop line, with shock cord, to minimize hydrodynamic noise. The surface line included a Spotter V2 buoy that provided real-time tracking of the location of the surface line. The recording system was deployed ten times in the CCZ, between November 2020 and October 2021. Deployment length was between two and seven days. All deployments were set to continuously record underwater sound with a sample frequency of 288 kHz. Acoustic data were analyzed using the CHORUS software to manually review recordings, and an FM signal detector (in MATLAB) was used to detect potential biological sounds. A variety of marine mammals were detected, including Delphinidae species, Physeter macrocephalus (sperm whales); and clicks likely to be from Ziphiidae species (beaked whales). Beaked whales have been previously visually sighted in the CCZ, but to our knowledge these might be the first acoustic recordings of them in the CCZ.
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Li, Shenghao, Zhenglin Li, Wen Li e Yanxin Yu. "Three-Dimensional Sound Propagation in the South China Sea with the Presence of Seamount". Journal of Marine Science and Engineering 9, n. 10 (1 ottobre 2021): 1078. http://dx.doi.org/10.3390/jmse9101078.
Testo completoAbstract (sommario):
Seamounts have important effects on sound propagation in deep water. A sound propagation experiment was conducted in the South China Sea in 2016. The three-dimensional (3D) effects of a seamount on sound propagation are observed in different propagation tracks. Ray methods (BELLHOP N×2D and 3D models) are used to analyze and explain the phenomena. The results show that 3D effects have obvious impacts on a sound field within a horizontal refraction zone behind the seamount because some sound beams cannot reach the receiver for the horizontal refraction effects, which impacts the sound field within a certain angle range behind the seamount. The arrival structure results show that the eigenrays after horizontal reflection will arrive at the receiver earlier than those obtained from the two-dimensional (2D) model within the horizontal refraction zone behind the seamount. This means that the horizontal reflection effect of a seamount will cause the shortening of sound propagation paths. Finally, in the reflection zone in front of the seamount, the 2D and 3D TL results show that the shape of the reflection zone is similar to an “arch” type, and the horizontal refraction of sound waves has little effect on the TLs in the reflection zone of a seamount.
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Monazzam, Mohammad Reza, Elham Karimi, Parvin Nassiri, Lobat Taghavi e Samaneh Karbalaei. "Outdoor Noise Pollution Mapping Case Study: A District of Tehran". Fluctuation and Noise Letters 13, n. 04 (20 ottobre 2014): 1450027. http://dx.doi.org/10.1142/s0219477514500278.
Testo completoAbstract (sommario):
The main objective of this study was to investigate the noise levels at different land uses of District 14 in Tehran. For this purpose, a total number of 91 sampling stations were selected. Afterwards, the equivalent sound pressure level in each station was measured at three occasions of morning (7–9 am), noon (12–3 pm), and evening (5–8 pm). Based on the conformability requirement of each land uses, noise levels was divided in three zones wherein the land uses are exposed to different noise levels was estimated. The obtained results indicated that 8.79% of 78 land uses (residential, recreational and medical) in the Zone 1 were exposed to acceptable range of sound pressure level while the rest suffers from unacceptable noise levels. Among 10 land uses of Zone 2 (commercial–residential), 2.19% were within the acceptable range and 8.78% were in unacceptable range. None of the three land uses in Zone 3 were within the acceptable range. Accordingly, the Zone 3 was recognized to be in a critical condition. In other words, about 88.99% of the total and uses in the Zone 3 is exposed to unaccepted able noise level. Comparing with the standard equivalent sound pressure level of 55 dB(A) presented, the residential land use with the equivalent sound pressure level of 19.27 dB(A) accounted for the highest standard deviation. This is due to proximity of most of the residential areas to the crowded highways and streets.
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Zhong, Jiaxin, Tao Zhuang, Ray Kirby, Mahmoud Karimi, Haishan Zou e Xiaojun Qiu. "Quiet zone generation in an acoustic free field using multiple parametric array loudspeakers". Journal of the Acoustical Society of America 151, n. 2 (febbraio 2022): 1235–45. http://dx.doi.org/10.1121/10.0009587.
Testo completoAbstract (sommario):
This paper investigates the feasibility of remotely generating a quiet zone in an acoustic free field using multiple parametric array loudspeakers (PALs). A primary sound field is simulated using point monopoles located randomly in a two-dimensional plane, or three-dimensional (3D) space, whereas the secondary sound field is generated by multiple PALs uniformly distributed around the circumference of a circle sitting on the same plane as the primary sources, or on the surface of a sphere for 3D space. A quiet zone size is defined as the diameter of the maximal circular zone within which the noise reduction is greater than 10 dB. The size of this quiet zone is found to be proportional to 0.19 λN for N secondary sources with a wavelength λ when the primary and secondary sources are in the same plane, whereas it is found to be 0.55 λN1/2 for the 3D case. The size of the quiet zones generated by PALs is similar to that observed with traditional omnidirectional loudspeakers; however, the effects of using PALs on the sound field outside the target zone is much smaller due to their sharp radiation directivity and slow decay rate along the propagation distance. Experimental results are also presented to validate these numerical simulations.
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Nystuen, Jeffrey A., e Ali R. Kolaini. "Exploring the surf zone using ambient sound". Journal of the Acoustical Society of America 102, n. 5 (novembre 1997): 3103. http://dx.doi.org/10.1121/1.420514.
Testo completo
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Sammelmann, Gary, Grant Deane, Svein Vagle e David Farmer. "Propagation of sound in the surf zone". Journal of the Acoustical Society of America 111, n. 5 (2002): 2460. http://dx.doi.org/10.1121/1.4778491.
Testo completo
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Fang, Xiaoyue, Yun Wu, Junjie Song, Hang Yin, Liang Zhou, Qiude Zhang, Zhaohui Quan, Mingyue Ding e Ming Yuchi. "Zone-Shrinking Fresnel Zone Travel-Time Tomography for Sound Speed Reconstruction in Breast USCT". Sensors 20, n. 19 (28 settembre 2020): 5563. http://dx.doi.org/10.3390/s20195563.
Testo completoAbstract (sommario):
Many studies have been carried out on ultrasound computed tomography (USCT) for its potential application in breast imaging. The sound speed (SS) image modality in USCT can help doctors diagnose the breast cancer, as the tumor usually has a higher sound speed than normal tissues. Travel time is commonly used to reconstruct SS image. Raypath travel-time tomography (RTT) assumes that the sound wave travels through a raypath. RTT is computationally efficient but with low contrast to noise ratio (CNR). Fresnel zone travel-time tomography (FZTT) is based on the assumption that the sound wave travels through an area called the Fresnel zone. FZTT can provide SS image with high CNR but low accuracy due to the wide Fresnel zone. Here, we propose a zone-shrinking Fresnel zone travel-time tomography (ZSFZTT), where a weighting factor is adopted to shrink the Fresnel zone during the inversion process. Numerical phantom and in vivo breast experiments were performed with ZSFZTT, FZTT, and RTT. In the numerical experiment, the reconstruction biases of size by ZSFZTT, FZTT, and RTT were 0.2%~8.3%, 2.3%~31.7%, and 1.8%~25%; the reconstruction biases of relative SS value by ZSFZTT, FZTT, and RTT were 24.7%~42%, 53%~60.8%, and 30.3%~47.8%; and the CNR by ZSFZTT, FZTT, and RTT were 67.7~96.6, 68.5~98, and 1.7~2.7. In the in vivo breast experiment, ZSFZTT provided the highest CNR of 8.6 compared to 8.1 by FZTT and 1.9 by RTT. ZSFZTT improved the reconstruction accuracy of size and the relative reconstruction accuracy of SS value compared to FZTT and RTT while maintaining a high CNR similar to that of FZTT.
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Wang, Shuping, Qiaoxi Zhu, Jiancheng Tao e Xiaojun Qiu. "Acoustic contrast control in two regions in car cabins". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 268, n. 3 (30 novembre 2023): 5452–58. http://dx.doi.org/10.3397/in_2023_0770.
Testo completoAbstract (sommario):
Personal audio systems that generate different sound zones in different regions have received much interest recently, especially in car cabins. The feasibility of creating a listening zone at the driver's seat and a quiet zone at the passenger's seat with the headrest speakers, door loudspeakers, and the combination of them is investigated in this manuscript. A finite element model of a car interior is created in COMSOL Multiphysics to obtain the acoustic transfer functions and the acoustic contrast control performances of 4 different speaker configurations are compared with each other. It is found that the 4 headrest speakers achieve better acoustic contrast control performance than the door speakers at low frequencies, while the sound pressure level distribution tends to be more uniform in the bright zone when using the door speakers.
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Covey, E. "Response properties of single units in the dorsal nucleus of the lateral lemniscus and paralemniscal zone of an echolocating bat". Journal of Neurophysiology 69, n. 3 (1 marzo 1993): 842–59. http://dx.doi.org/10.1152/jn.1993.69.3.842.
Testo completoAbstract (sommario):
1. Connectional evidence suggests that the dorsal nucleus of the lateral lemniscus (DNLL) and the paralemniscal zone (PL) function as centers for binaural analysis interposed between the superior olivary complex and the midbrain. In addition, the DNLL is known to be a major source of inhibitory input to the midbrain. The aim of this study was to characterize the response properties of neurons in DNLL and PL of the echolocating bat Eptesicus fuscus, a species that utilizes high-frequency hearing and that might be expected to have a large proportion of neurons responsive to interaural differences in sound level. 2. Auditory stimuli were presented monaurally or binaurally to awake animals, and responses of single units were recorded extra-cellularly with the use of glass micropipettes. 3. Below the ventrolateral border of the inferior colliculus is a region that contains large gamma-aminobutyric acid-positive neurons. On the basis of its immunohistochemical reactivity, this entire region could be considered as DNLL. However, within the area, there was an uneven distribution of binaural responses. Caudally, binaural neurons made up 84% (41/49) of those tested, but rostrally only 29% (6/21). For this reason the rostral area is considered as a separate functional subdivision and referred to as the dorsal paralemniscal zone (DPL). PL is located ventral to DPL and medial to the intermediate and ventral nuclei of the lateral lemniscus; in PL 88% (14/16) of neurons were binaural. 4. Most neurons responded only to a contralateral stimulus when sounds were presented monaurally. Out of 49 neurons in DNLL, 42 responded only to a contralateral sound, 1 responded only to an ipsilateral sound, and 6 responded to sound at either ear. In the DPL, all of the 21 neurons tested responded to a contralateral sound and none to an ipsilateral sound. Out of 16 neurons in the PL, 11 responded only to a contralateral sound, 1 responded only to an ipsilateral sound, and 4 responded to sound at either ear. 5. When sounds were presented at both ears simultaneously, several different patterns of binaural interaction occurred. The most common pattern was suppression of the response to sound at one ear by sound at the other ear. In DNLL, 57% (28/49) of neurons showed this type of binaural interaction. Another 10% (5/49) showed facilitation at some interaural level differences and suppression at others, and another 10% (5/49) showed facilitation at some interaural level differences but no suppression.(ABSTRACT TRUNCATED AT 400 WORDS)
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Cheng, Jiazheng, Hao Gao, Keyu Pan, Xuelei Feng e Yong Shen. "Multi-objective optimization for generation of personal sound zone". Journal of the Acoustical Society of America 153, n. 1 (gennaio 2023): 149–58. http://dx.doi.org/10.1121/10.0016822.
Testo completoAbstract (sommario):
Personal Sound Zone (PSZ) allows listeners to enjoy their individual sound without being disturbed by sound from other zones. Acoustic contrast, signal distortion, and array effort are the most frequently used metrics for measuring the performance of a PSZ system. However, usually, the three metrics cannot be optimized at the same time. A trade-off between the three metrics has to be made when designing a PSZ system. In this paper, two generalized methods based on multi-objective optimization are proposed for dealing with all possible trade-off problems between the three metrics in PSZ. Optimality analysis of the two proposed methods is taken, and the relationship between the two proposed methods is investigated. Numerical simulations are presented to validate the efficacy and flexibility of the two proposed methods.
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Zhao, Sipei, e Qiaoxi Zhu. "Comparative study of loudspeaker position optimization techniques for multizone sound field reproduction". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, n. 4 (1 agosto 2021): 2486–93. http://dx.doi.org/10.3397/in-2021-2150.
Testo completoAbstract (sommario):
Mutlizone sound field reproduction aims to generate personal sound zones in a shared space with multiple loudspeakers. Conventionally, loudspeakers are placed to form a regular pattern such as circular, arc or linear array, which are empirical rather than optimal mainly for the convenience of physical placement. Recently, several algorithms have been proposed to select a fixed number of loudspeaker locations from a large set of candidate positions, such as the sparse regularization (i.e. Lasso and Elastic Net) methods, the Constrained Match Pursuit (CMP) method, the Gram-Schmidt Orthogonalization (GSO) method etc. Most of these methods were investigated for single-zone rather than mulit-zone sound field reproduction based on the pressure matching techniques. This paper compares the performance of the state-of-the-art techniques for loudspeaker position optimization in a multizone sound field reproduction system in terms of reproduction error, acoustic contrast and array effort. Simulation results demonstrate that the CMP-LS method shows the best performance in terms of lower MSE and higher AC while the Lasso method needs the lowest AE.
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Wang, Jiarui, Thushara Abhayapala, Jihui (Aimee) Zhang e Prasanga N. Samarasinghe. "Multizone reproduction by matching the velocity vectors". Journal of the Acoustical Society of America 154, n. 4_supplement (1 ottobre 2023): A208. http://dx.doi.org/10.1121/10.0023300.
Testo completoAbstract (sommario):
This paper proposes a velocity-based multizone reproduction method, which reproduces the velocity vectors throughout each listening zone. Velocity vectors are related to the localization of sound below 700 Hz. Previous work considered reproducing the velocity vectors at sweet spots or on the listening zone’s boundary, and usually involved measurements using multiple velocity sensors. In this paper, in each listening zone, the velocity vectors are calculated from the spherical harmonic coefficients of the pressure, which are obtained by a spherical microphone array. The calculation of the velocity vectors is based on the sound field translation formula. Moreover, by reproducing the desired velocity vectors throughout each listening zone, listener's movement within each zone is allowed. To enlarge the size of the listening zone, the sound field in each listening zone is expressed by a sparse distribution of plane waves that results in the same velocity vectors. The pressure transfer functions between each loudspeaker and each listening zone are measured by placing a spherical microphone array at multiple spatial sampling points within each listening zone. The loudspeaker driving functions are calculated by matching the velocity vectors due to the sparse distribution of plane waves in each listening zone.
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Liang, Yan, Zhou Meng, Yu Chen, Zemin Zhou e Mo Chen. "Vertical Correlation and Array Gain Analysis for Vertical Line Array in Deep Water". Applied Sciences 10, n. 14 (8 luglio 2020): 4709. http://dx.doi.org/10.3390/app10144709.
Testo completoAbstract (sommario):
Array gain (AG) is significant in evaluating the detection performance of the vertical line array, which is directly determined by the correlation of signal and noise, respectively. In this paper, we analyze the vertical correlation for a 16-element vertical line array experimented in the deep ocean in 2016. The ray interference theory is utilized to interpret the mechanism of the vertical correlation of the sound field in different zones. In the direct-arrival zone, the direct rays and once-surface-reflected rays are two dominated components, whose arrival time difference for each element are nearly the same, and the vertical correlation is high. In the shadow zone, the sound field is mainly dominated by bottom-reflected rays and the vertical correlation decreases due to different grazing angles and arrival times of each ray. Different from the previous assumption of noise independence, the effect of noise correlation on the AG is analyzed through the measured marine environmental noise. Results indicate that the noise correlation coefficients in two zones are low but not 0. In the direct-arrival zone, AG is about 10 dB, very close to the ideal value of 10 log M . AG even exceeds it when NG is negative. Moreover, AG in the direct-arrival zone is higher than the one in the shadow zone.
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A. Ahire, Bhawana, e Sachin R. Sakhare. "Sound Prohibited Zone for Smart Cities using IoT". Tehnički glasnik 15, n. 1 (4 marzo 2021): 92–97. http://dx.doi.org/10.31803/tg-20210205091148.
Testo completoAbstract (sommario):
One of the dominant causes of noise pollution is the disruptive honking while traveling on a road and is particularly problematic as well as resulting in irritating sound. This results in many effects that need to be addressed taking into consideration stress, depression, mental and physical illnesses. The proposed system comprises of an embedded module that will be of great benefit to citizens of society adjacent to heavily populated roads, students studying in schools near crowded roads, patients admitted to roadside hospitals, etc. Noise Armor's alternative approach needs immense expenditure and personnel for both repair and surveillance as there is the need for expensive noise absorbers. By developing a real-time (smart) honking device that automatically allows vehicles on the road to reduce the volume of horn near conscious areas such as schools , hospitals, old-age homes, baby care centers and other organizations that are adversely damaged, our research aims to develop an effective solution for excessive honking.
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Wang, Song, e Cong Zhang. "A Stable Sound Field Control Method for a Personal Audio System". Applied Sciences 13, n. 22 (10 novembre 2023): 12209. http://dx.doi.org/10.3390/app132212209.
Testo completoAbstract (sommario):
A personal audio system has a wide application prospect in people’s lives, which can be implemented by sound field control technology. However, the current sound field control technology is mainly based on sound pressure or its improvement, ignoring another physical property of sound: particle velocity, which is not conducive to the stability of the entire reconstruction system. To address the problem, a sound field method is constructed in this paper, which minimizes the reconstruction error in the bright zone, minimizes the loudspeaker array effort in the reconstruction system, and at the same time controls the particle velocity and sound pressure of the dark zone. Five unevenly placed loudspeakers were used as the initial setup for the computer simulation experiment. Simulation results suggest that the proposed method is better than the PM (pressure matching) and EDPM (eigen decomposition pseudoinverse method) methods in the bright zone in an acoustic contrast index, the ACC (acoustic contrast control) method in a reconstruction error index, and the ACC, PM, and EDPM methods in the bright zone in a loudspeaker array effort index. The average array effort of the proposed method is the smallest, which is about 9.4790, 8.0712, and 4.8176 dB less than that of the ACC method, the PM method in the bright zone, and the EDPM method in the bright zone, respectively, so the proposed method can produce the most stable reconstruction system when the loudspeaker system is not evenly placed. The results of computer experiments demonstrate the performance of the proposed method, and suggest that compared with traditional methods, the proposed method can achieve more balanced results in the three indexes of acoustic contrast, reconstruction error, and loudspeaker array effort on the whole.
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La Manna, Gabriella, Marta Picciulin, Alessia Crobu, Francesco Perretti, Fabio Ronchetti, Michele Manghi, Alberto Ruiu e Giulia Ceccherelli. "Marine soundscape and fish biophony of a Mediterranean marine protected area". PeerJ 9 (15 dicembre 2021): e12551. http://dx.doi.org/10.7717/peerj.12551.
Testo completoAbstract (sommario):
Background Marine soundscape is the aggregation of sound sources known as geophony, biophony, and anthrophony. The soundscape analysis, in terms of collection and analysis of acoustic signals, has been proposed as a tool to evaluate the specific features of ecological assemblages and to estimate their acoustic variability over space and time. This study aimed to characterise the Capo Caccia-Isola Piana Marine Protected Area (Italy, Western Mediterranean Sea) soundscape over short temporal (few days) and spatial scales (few km) and to quantify the main anthropogenic and biological components, with a focus on fish biophonies. Methods Within the MPA, three sites were chosen each in a different protection zone (A for the integral protection, B as the partial protection, and C as the general protection). In each site, two underwater autonomous acoustic recorders were deployed in July 2020 at a depth of about 10 m on rocky bottoms. To characterise the contribution of both biophonies and anthrophonies, sea ambient noise (SAN) levels were measured as sound pressure level (SPL dB re: 1 μ Pa-rms) at eight 1/3 octave bands, centred from 125 Hz to 16 kHz, and biological and anthropogenic sounds were noted. Fish sounds were classified and counted following a catalogue of known fish sounds from the Mediterranean Sea based on the acoustic characteristic of sound types. A contemporary fish visual census had been carried out at the test sites. Results SPL were different by site, time (day vs. night), and hour. SPLs bands centred at 125, 250, and 500 Hz were significantly higher in the daytime, due to the high number of boats per minute whose noise dominated the soundscapes. The loudest man-made noise was found in the A zone, followed by the B and the C zone, confirming that MPA current regulations do not provide protection from acoustic pollution. The dominant biological components of the MPA soundscape were the impulsive sounds generated by some invertebrates, snapping shrimps and fish. The vast majority of fish sounds were recorded at the MPA site characterized by the highest sound richness, abundance, and Shannon-Wiener index, coherently with the results of a fish visual census. Moreover, the acoustic monitoring detected a sound associated with a cryptic species (Ophidion spp.) never reported in the study area before, further demonstrating the usefulness of passive acoustic monitoring as a complementary technique to species census. This study provides baseline data to detect future changes of the marine soundscapes and some suggestions to reduce the impact of noise on marine biodiversity.
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Amorim, M. C. P., J. M. Simões e P. J. Fonseca. "Acoustic communication in the Lusitanian toadfish, Halobatrachus didactylus: evidence for an unusual large vocal repertoire". Journal of the Marine Biological Association of the United Kingdom 88, n. 5 (24 giugno 2008): 1069–73. http://dx.doi.org/10.1017/s0025315408001677.
Testo completoAbstract (sommario):
The Lusitanian toadfish Halobatrachus didactylus (Bloch & Schneider) (Batrachoididae) is a well-known sound producer that has an unusual large acoustic repertoire for fish. This repertoire consists so far of five distinct sound categories: boatwhistles, grunt trains, croaks, double croaks and a mixed grunt–croak call. Sixteen males that spontaneously occupied artificial concrete nests placed in the intertidal zone of the Tagus estuary (Portugal) were recorded over 8 days in June/July 2006. During the analysis of the recordings new sound emissions were found. Long grunt trains that sounded to the human ear like a running engine were heard. These sounds differ from the normal grunt trains by having a lower amplitude, a much longer duration (tens of seconds versus <1 second) and more grunts per call. Other new sound emissions (e.g. triple croaks) were also registered but were heard less frequently. The incidence of the various sound types is given.
41
Hu, Meiling, Haishan Zou, Jing Lu e Mads Græsbøll Christensen. "Maximizing the acoustic contrast with constrained reconstruction error under a generalized pressure matching framework in sound zone control". Journal of the Acoustical Society of America 151, n. 4 (aprile 2022): 2751–59. http://dx.doi.org/10.1121/10.0010256.
Testo completoAbstract (sommario):
In sound zone control, the pressure matching (PM) algorithm is generally considered to achieve relatively low acoustic contrast (AC) regardless of the desired sound field. In this paper, we propose a generalized PM framework to generate a desired sound field with variable AC. The framework indicates that the choice of the desired sound field solely determines the AC performance of PM when the physical setting and acoustic environment remain unchanged. In the extreme, PM obtains the same AC as the acoustic contrast control method, which is widely accepted as the algorithm leading to the maximum AC. Based on the proposed framework, we design a variant coordinate descent algorithm to adjust the desired sound field by maximizing the AC under the constraint of the reconstruction error. Simulation results validate the efficacy and flexibility of the proposed framework in constrained sound zone control.
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Bhatt, EeShan C., Arthur B. Baggeroer e Robert A. Weller. "Overflow waters in the western Irminger Sea modify deep sound speed structure and convergence zone propagation". Journal of the Acoustical Society of America 155, n. 2 (1 febbraio 2024): 1216–29. http://dx.doi.org/10.1121/10.0024350.
Testo completoAbstract (sommario):
Deep sound speed structure in the western Irminger Sea is found to be highly dynamic in comparison to the adiabatic (uniform) sound speed gradient underpinning data assimilation and modeling efforts around the globe. A beamed source parabolic equation model is used to illustrate how the resulting non-uniform sound speed structure at 1 to 1.5 km in depth and sound speed inversion near the seafloor produce observable effects on acoustic signals between a shallow source and shallow vertical line array at convergence zone ranges. Beamforming analysis shows that a uniform sound speed gradient leads to “ideal” interference patterns that do not capture or represent modeled convergence zone properties, such as location, strength, and sharpness. Overall findings suggest that in situ information about sound speed below 1 km is necessary for low frequency, long-range propagation studies, particularly in areas of complex thermohaline circulation.
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Wu, Yushen, Jixing Qin, Shuanglin Wu, Zhenglin Li, Mengyuan Wang, Yiming Gu e Yang Wang. "Mesoscale Eddy Effects on Vertical Correlation of Sound Field and Array Gain Performance". Remote Sensing 16, n. 11 (23 maggio 2024): 1862. http://dx.doi.org/10.3390/rs16111862.
Testo completoAbstract (sommario):
To solve the problem of array detection performance in environments with mesoscale eddies, this study utilizes the Gaussian eddy model to describe the sound speed structure disturbed by eddies. Through numerical simulations, the corresponding sound field is obtained, and the transmission loss influenced by the eddy is analyzed. Furthermore, to investigate the relation between the array gain and spatial correlation in the eddy environments, the differences in vertical correlation at different positions and their effects on the vertical array gain of conventional beamforming (CBF) are studied. When the source is around the eddy center, the conclusions drawn are as follows: (1) The presence of an eddy changes the turning-point depth and the sound field distribution, significantly affecting the direct sound region and the first convergence zone, while having a minor impact on the first shadow zone. (2) In different eddy-induced environments, the first convergence zone maintains a high vertical correlation, but the vertical correlation of the direct sound region is greatly influenced by the eddy. (3) The array gain of CBF is consistent with the vertical correlation. When the correlation between each element of the sound field is great, the array gain increases with the number of array elements.
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Bhaladhare, Prof Dr P. R. "Innovative System for Metropolitan Sound Pollution Management". International Journal for Research in Applied Science and Engineering Technology 9, n. VI (14 giugno 2021): 914–18. http://dx.doi.org/10.22214/ijraset.2021.35116.
Testo completoAbstract (sommario):
According to population Reference Bureau, the current world population is 7.4 Billion. At present, a total number of the vehicle is 1.2 Billion according to survey and it will be 2 Billion up to 2035. Cars and trucks turn out pollution throughout their life, as well as pollution get emit throughout the vehicle operation, refuelling, producing, and disposal. Due to heavier traffic and powerful engines, noise level in cities is rapidly increasing. Our proposed system provides the solution to these problems. Our system Monitor the noise pollution created by vehicle and if any vehicle crosses its threshold value then it will get reported on the LCD and generate notification for municipal corporation. In this project we are using GPS for getting current location of vehicle & software panel checks that whether it is in no honking zone or not, if it is no honking zone then software panel informs Arduino (microcontroller) to control the horn. If user is out of honking zone then horn will reset to its original value.
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Van Renterghem, Timothy, e Kirill Horoshenkov. "Turbulent scattering in upwardly refracting atmospheres : towards a practical approach". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, n. 4 (1 febbraio 2023): 3972–77. http://dx.doi.org/10.3397/in_2022_0566.
Testo completoAbstract (sommario):
Neglecting turbulent scattering when modelling sound propagation in an upwardly refracting atmosphere leads to unrealistically low levels. Engineering models then typically impose a distance independent constant value for the sound pressure level relative to free field propagation. However, such an approach neglects the strong temporal variability in level one might observe in such an acoustic shadow zone, depending on whether the atmospheric boundary layer is either strongly or weakly scattering. In this work, a modelling framework is presented to account for the effect of such changing scattering contributions, showing that level variations might be as large as 20 dB in such zones. This work contributes to predicting more accurate long-term sound pressure level distributions e.g. near wind turbines.
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Kushlyk, Oksana. "Дериваційний потенціал дієслів-ономатопів на позначення супровідного звуковияву у процесі споживання". Theoria et Historia Scientiarum 20 (26 giugno 2024): 79–109. http://dx.doi.org/10.12775/ths.2023.004.
Testo completoAbstract (sommario):
The article highlights the role of the stem as a typologizing factor in studying Ukrainian and Polish word formation. The object of attention is sound-imitating verbs that stand for the accompanying sounds produced in the act of food intake as a daily physiological human need. Based on the word-formation-paradigmatic principle of systematizing the factual material, adequate to the base-centric aspect of derivatology development in Slavic languages, the author structures deverbative found in both languages by morphological zones, clarifies the continuum of semantic positions realized by deverbatives within substantive morphological zone, determines a set of word-forming means as explicators of these semantic positions, motivates the nature of semantic relations between the semantic structure of the stem and derived words in order to predict the further development of the semantic structure of the stem, identifies the factors that activate or, conversely, slow down the word-forming capacity of top verbs, and on this basis establishes the word-forming potential of sound imitating verbs that indicate the accompanying sounds produced in the act of food intake and appraises the degree of functional correspondence of the described word-forming phenomena in Ukrainian and Polish as genetically related languages.
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AlSaleem, Saleem S., Abdulbasit Almhafdy, Umberto Berardi, Amal A. Al-Shargabi e Ahmed AbdelMonteleb M. Ali. "Field Measurements and Human Perception to Remediate Noise Pollution in the Urban Public Parks in Saudi Arabia". Sustainability 15, n. 13 (23 giugno 2023): 9977. http://dx.doi.org/10.3390/su15139977.
Testo completoAbstract (sommario):
The deleterious effects of noise pollution on public health have been well documented, with traffic noise being identified as a significant contributor to stress and adverse impacts on the human body and mind. In this study, sound levels at 12 different points in Al-Oqailat Park in Buraydah, Saudi Arabia, were measured using a sound level meter (SLM), with the study’s primary objective being to conduct this measurement. The experimental results were then compared with perception measurements collected from users who frequently visited Al-Oqailat park. Sound measurements were taken in four different zones (A, B, C, and D) during rush hours between 1:30 p.m. and 5:20 p.m. It was found that noise levels at point A1 peaked at 79 dBA at 4:40 p.m., while the lowest level recorded was 41.1 dBA at point D2 at 2:35 p.m. The range of noise levels varied between 79 and 41 dBA, with a rate of decline of 48.10%. Zones A and B seemed to have the highest noise levels during rush hours, since they were located closest to King Fahd Road and Al-Adl Street, while zone D exhibited the lowest noise levels due to its location as a parking lot for Buraydah Court. An intermediate noise level was found in zone C, in the middle of Al-Oqailat park. The people perception results, completed by 84 park visitors, showed that zone A was identified as having exceptionally high noise levels compared to the other zones, with zone D having the lowest levels. These results were consistent with the experimental findings and reflected that the points along King Fahd Road and Al-Adl Street had the highest noise levels. Overall, the research highlighted the dominance of car traffic and horns as the primary sources of noise pollution in and around Al-Oqailat Park, emphasizing the significance of meticulous site selection for parks in urban areas.
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Wang, Song, e Cong Zhang. "Two Sound Field Control Methods Based on Particle Velocity". Electronics 11, n. 14 (21 luglio 2022): 2275. http://dx.doi.org/10.3390/electronics11142275.
Testo completoAbstract (sommario):
In recent years, a variety of sound field control methods have been proposed for the generation of separated sound regions. Different algorithms control the physical properties of the generated sound field to different degrees. The existing methods mainly focus on sound pressure restoration and its related improvement. When the loudspeaker array is non-uniformly placed, the reconstruction system is not stable enough. To solve this problem, this paper proposes two sound field control methods related to particle velocity. The first method regulates the reconstruction error of particle velocity in the bright zone and the square of particle velocity in the dark zone; the second method regulates the reconstruction error of sound pressure and particle velocity in the bright zone and the square of sound pressure and particle velocity in the dark zone. Five channel and twenty-two channel non-uniform loudspeaker systems were used for two-dimensional and three-dimensional computer simulation testing. Experimental results show that the two proposed methods have better tradeoffs in terms of acoustic contrast, reproduction error and array effort than traditional methods, especially the second proposed method. In the two-dimensional experiment, the maximum reductions of the average array efforts generated by the proposed methods were about 10 dB and 11 dB compared with the average array efforts generated by two traditional methods. In the three-dimensional experiment, the maximum reductions of the average array efforts generated by the proposed methods were about 8 dB and 2 dB compared with the average array efforts generated by two traditional methods. The smaller the array effort, the more stable the loudspeaker system. Therefore, the reconstruction systems produced by the proposed methods are more stable than those produced by the traditional methods.
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Calvo, David C., Abel L. Thangawng, Michael Nicholas e Christopher N. Layman. "Thin Fresnel zone plate lenses for focusing underwater sound". Applied Physics Letters 107, n. 1 (6 luglio 2015): 014103. http://dx.doi.org/10.1063/1.4926607.
Testo completo
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Yuan, Jing. "Quiet zone tuning in a non-ideal sound field". Mechanical Systems and Signal Processing 24, n. 1 (gennaio 2010): 281–88. http://dx.doi.org/10.1016/j.ymssp.2009.06.001.
Testo completo