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Acoustics, Volume 6, Issue 2 (June 2024) – 11 articles

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20 pages, 1654 KiB  
Article
Atmospheric Sound Propagation over Rough Sea: Numerical Evaluation of Equivalent Acoustic Impedance of Varying Sea States
by Andrea Vecchiotti, Teresa J. Ryan, Joseph F. Vignola and Diego Turo
Acoustics 2024, 6(2), 489-508; https://doi.org/10.3390/acoustics6020026 - 23 May 2024
Viewed by 13
Abstract
This work presents a numerical study on atmospheric sound propagation over rough water surfaces with the aim of improving predictions of sound propagation over long distances. A method for generating pseudorandom sea profiles consistent with sea wave spectra is presented. The proposed method [...] Read more.
This work presents a numerical study on atmospheric sound propagation over rough water surfaces with the aim of improving predictions of sound propagation over long distances. A method for generating pseudorandom sea profiles consistent with sea wave spectra is presented. The proposed method is suited for capturing the logarithmic nature of the energy distribution of the waves. Sea profiles representing fully developed seas for sea states 2, 3, 4, and 5 are generated from the Elfouhaily et al. (ECKV) sea wave spectra. Excess attenuation caused by refraction and surface roughness is predicted with a parabolic equation (PE) solver. A novel method for estimating equivalent effective impedance based on PE predictions at different sea states is presented. Parametric expressions using acoustic frequency and significant wave height are developed for effective surface impedances. In this work, sea surface roughness is on a scale comparable with the acoustic wavelength. Under this condition, the acoustic scattering is primarily incoherent. This work shows the limitations of using an equivalent surface impedance in such incoherent scattering cases. Full article
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19 pages, 655 KiB  
Article
Training a Filter-Based Model of the Cochlea in the Context of Pre-Trained Acoustic Models
by Louise Coppieters de Gibson and Philip N. Garner
Acoustics 2024, 6(2), 470-488; https://doi.org/10.3390/acoustics6020025 - 17 May 2024
Viewed by 392
Abstract
Auditory research aims in general to lead to understanding of physiological processes. By contrast, the state of the art in automatic speech processing (notably recognition) is dominated by large pre-trained models that are meant to be used as black-boxes. In this work, we [...] Read more.
Auditory research aims in general to lead to understanding of physiological processes. By contrast, the state of the art in automatic speech processing (notably recognition) is dominated by large pre-trained models that are meant to be used as black-boxes. In this work, we integrate a physiologically plausible (albeit simple filter-based) model of the cochlea into a much larger pre-trained acoustic model for speech recognition. We show that the hybrid system can be trained and evaluated with various combinations of fine-tuning and self-supervision. The results broadly show that the system automatically yields structures that are known to work well. Moreover, these structures lack artifacts that were apparent in (our) previous work using less sophisticated neural models. We conclude that the hybrid structure is an appropriate way to proceed in auditory research, more generally allowing the work to take advantage of larger models and databases from which it would not otherwise benefit. Full article
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31 pages, 7454 KiB  
Article
Enhancing Speaker Recognition Models with Noise-Resilient Feature Optimization Strategies
by Neha Chauhan, Tsuyoshi Isshiki and Dongju Li
Acoustics 2024, 6(2), 439-469; https://doi.org/10.3390/acoustics6020024 - 14 May 2024
Viewed by 343
Abstract
This paper delves into an in-depth exploration of speaker recognition methodologies, with a primary focus on three pivotal approaches: feature-level fusion, dimension reduction employing principal component analysis (PCA) and independent component analysis (ICA), and feature optimization through a genetic algorithm (GA) and the [...] Read more.
This paper delves into an in-depth exploration of speaker recognition methodologies, with a primary focus on three pivotal approaches: feature-level fusion, dimension reduction employing principal component analysis (PCA) and independent component analysis (ICA), and feature optimization through a genetic algorithm (GA) and the marine predator algorithm (MPA). This study conducts comprehensive experiments across diverse speech datasets characterized by varying noise levels and speaker counts. Impressively, the research yields exceptional results across different datasets and classifiers. For instance, on the TIMIT babble noise dataset (120 speakers), feature fusion achieves a remarkable speaker identification accuracy of 92.7%, while various feature optimization techniques combined with K nearest neighbor (KNN) and linear discriminant (LD) classifiers result in a speaker verification equal error rate (SV EER) of 0.7%. Notably, this study achieves a speaker identification accuracy of 93.5% and SV EER of 0.13% on the TIMIT babble noise dataset (630 speakers) using a KNN classifier with feature optimization. On the TIMIT white noise dataset (120 and 630 speakers), speaker identification accuracies of 93.3% and 83.5%, along with SV EER values of 0.58% and 0.13%, respectively, were attained utilizing PCA dimension reduction and feature optimization techniques (PCA-MPA) with KNN classifiers. Furthermore, on the voxceleb1 dataset, PCA-MPA feature optimization with KNN classifiers achieves a speaker identification accuracy of 95.2% and an SV EER of 1.8%. These findings underscore the significant enhancement in computational speed and speaker recognition performance facilitated by feature optimization strategies. Full article
(This article belongs to the Special Issue Developments in Acoustic Phonetic Research)
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26 pages, 7275 KiB  
Article
Angular Integral Autocorrelation for Speed Estimation in Shear-Wave Elastography
by Hamidreza Asemani, Irteza Enan Kabir, Juvenal Ormachea, Marvin M. Doyley, Jannick P. Rolland and Kevin J. Parker
Acoustics 2024, 6(2), 413-438; https://doi.org/10.3390/acoustics6020023 - 9 May 2024
Viewed by 471
Abstract
The utilization of a reverberant shear-wave field in shear-wave elastography has emerged as a promising technique for achieving robust shear-wave speed (SWS) estimation. However, many types of estimators cannot accurately measure SWS within such a complicated 3D wave field. This study introduces an [...] Read more.
The utilization of a reverberant shear-wave field in shear-wave elastography has emerged as a promising technique for achieving robust shear-wave speed (SWS) estimation. However, many types of estimators cannot accurately measure SWS within such a complicated 3D wave field. This study introduces an advanced autocorrelation estimator based on angular integration known as the angular integral autocorrelation (AIA) approach to address this issue. The AIA approach incorporates all the autocorrelation data from various angles during measurements, resulting in enhanced robustness to both noise and imperfect distributions in SWS estimation. The effectiveness of the AIA estimator for SWS estimation is first validated using a k-Wave simulation of a stiff branching tube in a uniform background. Furthermore, the AIA estimator is applied to ultrasound elastography experiments, magnetic resonance imaging (MRI) experiments, and optical coherence tomography (OCT) studies across a range of different excitation frequencies on tissues and phantoms, including in vivo scans. The results verify the capacity of the AIA approach to enhance the accuracy of SWS estimation and the signal-to-noise ratio (SNR), even within an imperfect reverberant shear-wave field. Compared to simple autocorrelation approaches, the AIA approach can also successfully visualize and define lesions while significantly improving the estimated SWS and SNR in homogeneous background materials and providing improved elastic contrast between structures within the scans. These findings demonstrate the robustness and effectiveness of the AIA approach across a wide range of applications, including ultrasound elastography, magnetic resonance elastography (MRE), and optical coherence elastography (OCE), for accurately identifying the elastic properties of biological tissues in diverse excitation scenarios. Full article
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5 pages, 193 KiB  
Editorial
Acoustics, Soundscapes and Sounds as Intangible Heritage
by Lidia Alvarez-Morales and Margarita Díaz-Andreu
Acoustics 2024, 6(2), 408-412; https://doi.org/10.3390/acoustics6020022 - 2 May 2024
Viewed by 788
Abstract
Since UNESCO unveiled its declaration for an integrated approach to safeguarding tangible and intangible cultural heritage in 2003 [...] Full article
(This article belongs to the Special Issue Acoustics, Soundscapes and Sounds as Intangible Heritage)
22 pages, 6153 KiB  
Article
Effect of Emotionalizing Sounds on the Estimation and Evaluation of Displayed Safety Distances
by Manuel Petersen, Deniz Yüksel and Albert Albers
Acoustics 2024, 6(2), 386-407; https://doi.org/10.3390/acoustics6020021 - 30 Apr 2024
Viewed by 574
Abstract
Musicological and traffic psychology research shows that emotions can be changed by certain tone combinations or sound characteristics and that emotions, in turn, influence our driving behavior. Nevertheless, there are no studies on how a dynamic active sound design could influence driving behavior [...] Read more.
Musicological and traffic psychology research shows that emotions can be changed by certain tone combinations or sound characteristics and that emotions, in turn, influence our driving behavior. Nevertheless, there are no studies on how a dynamic active sound design could influence driving behavior via changing the emotional state of drivers in certain driving situations. Based on a previous study, emotionalizing sounds, characterized by their capacity to evoke specific emotional responses in individuals, were created and used to investigate their effect on the perception of safety distances in an online study. To test this, participants made statements on the safety distance shown in videos of cars following scenarios combined with emotionalizing sounds. The results show a significant difference in the estimated safety distance for videos combined with sounds invoking positive emotions like light-heartedness vs. sounds invoking negative emotions like feeling threatened. The odds of the safety distance being evaluated as too small compared with appropriate were two to three times higher for some threatening sounds vs. the positive sounds. The results further suggest that threatening sounds influenced participants’ wishes to increase the depicted safety distances. The results show that emotionalizing sounds had effects on the participants, though not all were statistically significant. Full article
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12 pages, 2865 KiB  
Article
Modelling of Propagation Characteristics of Acoustic Pulse from Partial Discharge in Polymeric Insulating Materials
by Abdul Samad, Wah Hoon Siew, Martin J. Given, Igor V. Timoshkin and John Liggat
Acoustics 2024, 6(2), 374-385; https://doi.org/10.3390/acoustics6020020 - 26 Apr 2024
Viewed by 520
Abstract
The partial discharge (PD) event in high-voltage insulation releases energy, exerts mechanical pressure, and generates elastic waves. Detecting and locating these PD events through short-duration acoustic pulses is well established, particularly in gas-insulated systems and oil-insulated transformers. However, its full potential remains untapped [...] Read more.
The partial discharge (PD) event in high-voltage insulation releases energy, exerts mechanical pressure, and generates elastic waves. Detecting and locating these PD events through short-duration acoustic pulses is well established, particularly in gas-insulated systems and oil-insulated transformers. However, its full potential remains untapped in solid insulation systems, where the propagation capability of the acoustic pulse and the acoustic reflections pose fundamental challenges to the acoustic emission (AE) detection technique. This study investigates the influence of reflections and multiple paths on the propagating acoustic pulse in polymeric insulating materials using a finite element method (FEM) in COMSOL. It was observed that the reflections from the boundary influence the propagating pulse’s shape, peak magnitude, and arrival time. An analytical MATLAB model further quantifies the impact of multiple propagation paths on the shape, magnitude, and arrival time of the pulse travelling in a cylinder. Additionally, a Perfect Matched Layer (PML) was implemented in the COMSOL model to eliminate the reflections from the boundary, and it revealed that the acoustic pulse magnitude decreases with distance following the inverse square law. In essence, the models aid in measuring how reflections contribute to the observed signals, facilitating the precise identification of the source of the PD event in the tested system. Full article
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12 pages, 355 KiB  
Article
Tunnel Effect for Ultrasonic Waves in Tapered Waveguides
by Massimo Germano
Acoustics 2024, 6(2), 362-373; https://doi.org/10.3390/acoustics6020019 - 24 Apr 2024
Viewed by 534
Abstract
Traversal time in the tunneling effect for ultrasonic waves in tapered waveguides is derived considering its analogy with quantum and electromagnetic wave tunneling. If, as traversal time, the so-called phase time is considered, the ultrasonic wave packet shows the equivalent in acoustics of [...] Read more.
Traversal time in the tunneling effect for ultrasonic waves in tapered waveguides is derived considering its analogy with quantum and electromagnetic wave tunneling. If, as traversal time, the so-called phase time is considered, the ultrasonic wave packet shows the equivalent in acoustics of superluminality, i.e., the derived velocity, crosses the limit of bulk transverse ultrasonic waves in the medium of the waveguide that is the equivalent of c in the quantum and electromagnetic cases. The graphs clearly illustrating this so-called Hartman effect are obtained confirming the experimental results in the three different fields. Full article
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16 pages, 1963 KiB  
Article
A Two-Dimensional Liquid Sloshing Analysis in a Partially Filled Complicated-Shape Tank by the Schwarz–Christoffel Transformation
by Jing Lü, Xiaolong Zhu and Yang Yu
Acoustics 2024, 6(2), 346-361; https://doi.org/10.3390/acoustics6020018 - 19 Apr 2024
Viewed by 660
Abstract
The nonlinear sloshing of an incompressible fluid with irrotational flow in a complicated-shape tank due to horizontal excitation is studied with a semi-analytical method proposed in this study. In this method, the velocity potential function of a liquid in a complicated-shape tank is [...] Read more.
The nonlinear sloshing of an incompressible fluid with irrotational flow in a complicated-shape tank due to horizontal excitation is studied with a semi-analytical method proposed in this study. In this method, the velocity potential function of a liquid in a complicated-shape tank is estimated by using an approximate analytical transformation function from a complicated-shape region to a rectangular region. This function is obtained through Schwarz–Christoffel mapping and polynomial fitting. Nonlinear dynamic equations for the fluid–structure coupled system are developed based on the Hamilton–Ostrogradskiy principle. Nonlinear kinematic equations for the fluid–structure coupled system are derived based on the relationship between the liquid velocity and the free-surface equation. The Galerkin method is used to convert partial differential equations into ordinary differential equations. When tank movement is given, nonlinear models for the coupled system can be reduced to simple ones for liquid sloshing. Natural frequencies for the coupled system and liquid sloshing are analyzed, and the semi-analytical results agree with the numerical ones calculated with the software DampSlosh. Hydrodynamic forces and moments are also analyzed, and the semi-analytical results agree well with the numerical ones calculated with the Flow3D v10.1.1. Full article
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15 pages, 3723 KiB  
Article
Curvature Correction for Crack Depth Measurement Using Ultrasonic Pulse Velocity
by Dong Liu, Mengli Wu and Dimitri Donskoy
Acoustics 2024, 6(2), 331-345; https://doi.org/10.3390/acoustics6020017 - 27 Mar 2024
Viewed by 1185
Abstract
This study investigates the application of Ultrasonic Pulse Velocity (UPV) for crack depth estimation in cylindrical structures, focusing on two approaches: reference measurement and dual measurement. It addresses the challenge of applying UPV to curved surfaces, a scenario less studied than that of [...] Read more.
This study investigates the application of Ultrasonic Pulse Velocity (UPV) for crack depth estimation in cylindrical structures, focusing on two approaches: reference measurement and dual measurement. It addresses the challenge of applying UPV to curved surfaces, a scenario less studied than that of flat surfaces. The paper details the modification of UPV methodologies to account for curvature, presenting analytic solutions and numerical validations for both approaches. The findings reveal that curvature-adjusted equations yield accurate crack depth estimations, enhancing the reliability of UPV in diverse structural contexts. The study contributes to safer and more effective structural health monitoring, particularly in cylindrical infrastructures like columns and foundations. Full article
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33 pages, 9289 KiB  
Review
Research Progress on Thin-Walled Sound Insulation Metamaterial Structures
by Yumei Zhang, Jie Zhang, Ye Li, Dan Yao, Yue Zhao, Yi Ai, Weijun Pan and Jiang Li
Acoustics 2024, 6(2), 298-330; https://doi.org/10.3390/acoustics6020016 - 26 Mar 2024
Viewed by 1099
Abstract
Acoustic metamaterials (AMs) composed of periodic artificial structures have extraordinary sound wave manipulation capabilities compared with traditional acoustic materials, and they have attracted widespread research attention. The sound insulation performance of thin-walled structures commonly used in engineering applications with restricted space, for example, [...] Read more.
Acoustic metamaterials (AMs) composed of periodic artificial structures have extraordinary sound wave manipulation capabilities compared with traditional acoustic materials, and they have attracted widespread research attention. The sound insulation performance of thin-walled structures commonly used in engineering applications with restricted space, for example, vehicles’ body structures, and the latest studies on the sound insulation of thin-walled metamaterial structures, are comprehensively discussed in this paper. First, the definition and math law of sound insulation are introduced, alongside the primary methods of sound insulation testing of specimens. Secondly, the main sound insulation acoustic metamaterial structures are summarized and classified, including membrane-type, plate-type, and smart-material-type sound insulation metamaterials, boundaries, and temperature effects, as well as the sound insulation research on composite structures combined with metamaterial structures. Finally, the research status, challenges, and trends of sound insulation metamaterial structures are summarized. It was found that combining the advantages of metamaterial and various composite panel structures with optimization methods considering lightweight and proper wide frequency band single evaluator has the potential to improve the sound insulation performance of composite metamaterials in the full frequency range. Relative review results provide a comprehensive reference for the sound insulation metamaterial design and application. Full article
(This article belongs to the Special Issue Acoustic Materials)
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