bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing the benefits of hearing aids and cochlear implants in real-world listening environments
Authors: Maggs Lisa , Gradden Megan , Kan Alan , Sharma Mridula , Smith Zachary , Swanson Brett A. , Buchholz Joerg M.
Published: November 2023

Comparing outcomes between patients with bilateral hearing aids (HAs), bilateral cochlear implants (CIs), and bimodal fittings (CI + HA) are difficult because of the variations in hearing performance between the different devices and patient groups. This may impact patient counselling, device selection, and hearing outcomes for listeners with more severe hearing loss. This study seeks to identify the factors impacting the listening abilities of adults fitted with bilateral HAs, bilateral CIs, and bimodal fittings in noisy environments by comparing outcomes from commonly used clinical tests and a new task that emphasises realistic listening in background noise. By identifying these limiting factors from a variety of tests, optimising hearing aid fittings, and comparing between device configuration groups, the study will help understand where hearing aid devices no longer meet satisfactory individual outcomes, and a cochlear implant may improve long-term performance. This approach pushes toward considering real-world outcomes through realistic test measures when informing clinical counsel and device implantation or configuration recommendations. As such, adults with hearing loss can receive more tailored advice that validates their daily listening concerns and clinicians are granted a better understanding of how to improve the quality of life for their clients.
Implementation of a virtual reality-based executive function improvement system for children with ADHD using natural soundscape stimuli
Authors: Ahn Donghyun , Lee Ga Hyun , Roh Sungwon , Yoon Hyowon , Jeon Jin Yong
Published: November 2023

The aim of this study is to propose a new therapeutic approach for attention-deficit/hyperactivity disorder (ADHD) by integrating the healing elements of natural soundscapes with a virtual reality system (cave automatic virtual environment, CAVE) designed to stimulate multiple senses and enhance the functionality of individuals with ADHD. The participants, children aged 6 to 12, were selected based on the severity of their ADHD symptoms and were divided into two groups: those diagnosed with ADHD and those without. The participants were invited to partake in a CAVE/VR-based ADHD functional enhancement program, with two 40-min sessions per week over a total of 12 sessions. Biometric, cognitive, executive, and behavioral responses were measured to assess the effectiveness of the system for improving ADHD functionality. The collected data will be analyzed to identify differences in functional changes due to ADHD. Based on these findings, we expect to contribute to the development of more effective and targeted ADHD treatments in the future by better understanding the specific impacts of VR-based therapeutic interventions on the symptoms of children with ADHD.
Impact of direct-to-reverberation ratio and interaural cross-correlation on externalization in binaural audio rendering
Authors: Choe Taehun , Choi Jung-Woo
Published: November 2023

To achieve realistic binaural reproduction of spatial audio in a headphone scenario, addressing inside-the-head-locatedness is crucial, which can be accomplished through appropriate externalization techniques. Two acoustic cues, the direct-to-reverberation ratio (DRR) and interaural cross-correlation (IACC), are known to influence perceived externalization. However, the precise relationship between these cues and their combined effect has not been extensively studied. In this investigation, we aim to explore the relative contribution of DRR and IACC to externalization by examining various combinations of these two acoustic cues. To this end, participants were exposed to various binaural room impulse responses (BRIRs) synthesized to produce three distinct levels of DRRs and IACCs for two different source directions. The listening test was conducted in an anechoic chamber with participants’ eyes blindfolded to minimize the influence of room divergence effect. We also investigated the influence of head tracking by conducting experiments with and without head trackers. The correlation maps between externalization and the two acoustic cues were generated for each source direction. The study reveals that the contribution of the two acoustic cues differs with and without head tracking, and the joint contribution also varies depending on the source direction and amount of reflections included in the BRIR.
The contributions of level and near-field head-related transfer functions cues on auditory distance perception in a free field
Authors: Zhu Jun , Xie Bosun , Zhao Tong
Published: November 2023

In a free field, distance-dependent level (or loudness) and near-field HRTF (head-related transfer functions) are considered to be two primary cues for auditory distance perception. However, some recent experiments using virtual auditory display (VAD) have exhibited inconsistent or even controversial results, especially regarding with the contribution of near-field HRTF cues to distance perception. Possible reasons for the inconsistency may be that static VAD with coarse approximation of near-field HRTFs were used in these experiments, which cause poor perception of externalization and error in HRTF-related cues. To address this problem, a set of psychoacoustic experiment using dynamic VAD with accurate near-field HRTFs is conducted in present work. The perceived distances of virtual source at target distance less than 1.0 m and with or without level normalization are evaluated. The results indicate that HRTF cue alone enable distance perception in the lateral region. In contrast, HRTF cue alone is insufficient for distance perception in the front region. A collaboration of HRTF and level cue enhances distance perception in all directions. Therefore, the present experiment yields results similar to previous experiment using real source and validate the contribution of level and near-field HRTF cues to distance perception.
Low-frequency limit for binaural timing cues
Authors: Luo Jiaxin , Zeng Fan-Gang
Published: November 2023

Sound localization uses both interaural time differences (ITDs) and interaural level differences (ILDs). The ITD cue has a high-frequency boundary at 1500 Hz but is assumed to be limited only by the lowest audible frequency. We tested whether there is a low-frequency boundary for the ITD cue. Nineteen young, normal-hearing subjects participated in four experiments, in which 500-ms, 70-phon pure tones with various binaural cues were presented as a function of frequency from 62.5 to 2000 Hzin octave steps. The 70-phon level assured that audibility did not confound performance. Experiment 1 served as a control, in which a 10-dB ILD cue produced ∼90% correct lateralization at all frequencies. Experiment 2 measured lateralization accuracy with a 90-degree ITD cue, Experiment 3 measured the just-noticeable-difference from a 0-degree ITD standard, while Experiment 4 measured the binaural masking level difference in white noise. As expected, the listeners could not use the timingcue to perform these binaural tasks at 2000 Hz; Surprisingly, they showed significantly poorer performance at 62.5 Hz than mid frequencies. The band-pass characteristic result suggested a low-frequency boundary for binaural timing cues. This low boundary is not due to audibility but likely physical or physiological processes in the ear.
Design Of aesthetic acoustic metamaterials window panel based on Sierpiński triangle for sound-silencing with free airflow
Authors: Singh Sanjeet K. , Bhattacharya Shantanu
Published: November 2023

Design of high-efficiency, low frequency (<1000Hz) soundproof window or wall absorber which is transparent to airflow is presented. Due to the massive rise in human population and modernization, environmental noise has significantly risen globally. Prolonged noise exposure can cause severe physiological and psychological symptoms like nausea, headaches, fatigue, and insomnia. There has been continuous growth in building construction and infrastructure like offices, bus stops, and airports due to urban population. Generally, a ventilated window is used for getting fresh air into the room, but at the same time, unwanted noise comes along. Researchers used traditional approaches like noise barrier mats in front of the window or designed the entire window using sound-absorbing materials. However, this solution is not aesthetically pleasing, and at the same time, it is heavy and not adequate for low-frequency noise shielding. To address this challenge, we design a transparent hexagonal panel based on Sierpiński fractal triangle which is aesthetically pleasing, demonstrates normal incident sound absorption coefficient more than 0.96 around 700 Hz and transmission loss around 23 dB, while maintaining air circulation through triangular cutout. Next, we present a concept of fabrication of large acoustic panel for large-scale applications which lead to suppressing the urban noise pollution
Sound insulation design using membrane and locally resonant structure
Authors: Jang JunYoung , Song Kyungjun
Published: November 2023

In this study, we propose a design for sound insulation that utilizes a membrane and a locally resonant structure in tandem. A membrane serves as an excellent sound insulation structure in itself, but it can also be used to improve sound insulation performance by changing the dynamic characteristics of the sound insulation panel. In the case of the latter, there is an advantage of improving sound insulation performance in several bands without a large increase in weight. However, because the resonance band occurs at a relatively lower frequency than the anti-resonance band, it is difficult to block noise at frequencies below the anti-resonance band. To address this, we added a locally resonant structure that operates within the associated band. Because the anti-resonance caused by the locally resonant structure occurs at a lower frequency than the resonance, it can compensate for the deterioration band caused by the membrane-cavity. These effects have been verified through a sound transmission loss simulation of the unit structure at the normal and oblique incidence condition. Furthermore, the soundproofing bands of the product (plate and enclosure) were validated through SPL experiments.
Reconfigurable acoustic metamaterial chamber for low-frequency noise mitigation
Authors: Lee Heow Pueh , Chen Zhenyu , Chong Yung Boon , Lim Kian Meng
Published: November 2023

In this study, a new reconfigurable sonic crystal metamaterial chamber is proposed for noise mitigation. Each element of the sonic crystal is made on non-circular cross-section with built-in Helmholtz resonators. Numerical and experimental investigation of a single unit cell and the whole acoustic metamaterial chamber highlights the reliability and feasibility of the proposed sonic-crystal based meta-structure. Highly efficient sound insertion loss can be captured with a simple and easily accessed resonator. By carefully designing rotation support in each unit cell and manufacturing a 3-D printed base with periodic holes, the assembled resonators can be easily rotated, and the finite acoustic metamaterial chamber can be tuned to another configuration without the need of reprinting and redesigning the whole structure. By changing the configuration of the full chamber, the device can keep the insertion loss at a high level, while exhibiting a better ventilation ability. The reconfigurable, scalable, feasible, and controllable system can be easily applied to several practical scenarios like the silent zone in the city center, the ventilated noise isolate device for the machines, and the fully optically transparent ventilation sound-insulating structures.
Categorization and discrimination of Mandarin lexical tones by naïve English listeners
Authors: Li Yanping , Tyler Michael , Burnham Denis , Best Catherine
Published: November 2023

Unlike tone languages such as Mandarin, English lacks tones at the sub-lexical level. Accordingly, English listeners have difficulty perceptually assimilating tones as categorized or uncategorized native segments (Perceptual Assimilation Model, PAM: Best, 1995). While English listeners can categorize the four lexical tones of Mandarin, i.e., level contour, rising, dipping, and falling, when given question, statement, exclamation, and uncertainty intonations as category choices (So & Best, 2011, 2014), this does not address tone assimilation at the segmental level. We reasoned that they might assimilate tones as non-assimilable nonspeech patterns if given visual icons as tone category choices (flat, rising, dipping, and falling lines, respectively), with no reference being made to English intonation categories. Accordingly, 76 monolingual English listeners (M age = 24.85 years, 50 females) were set two tasks: to use visual icons to categorize Mandarin tones in naturally produced tone-words (/ga, ti, tu, pu/ × 4 tones) and to discriminate all six pairwise tone contrasts. All tone pairs showed ceiling-level discrimination, and listeners split their categorizations of falling and level stimuli between the falling and flat icons, suggesting that when given visual icons, tone-naïve English listeners perceive Mandarin tones as nonspeech acoustic patterns, which is consistent with PAM’s non-assimilation predictions.
Manipulation of affective speech and hemoglobin changes: A case study
Authors: Oh Chorong
Published: November 2023

Despite the wide use of functional near-infrared spectroscopy (fNIRS) in various cognitive research, it is under-investigated whether fNIRS can offer neural evidence of emotion vocalization, especially in older adults. In this study, an 74-year-old male participant without a cognitive or physical difficulty completed two speech tasks while an fNIRS device recorded Changes in Oxy-hemoglobin (HbO) and total hemoglobin (HbT) levels in the pre-frontal cortex. The three speech tasks were (1) affective speech (i.e., talking about happy and sad life events) and (2) neutral speech (i.e., explaining how to make a peanut butter and jelly sandwich). The speech tasks were audio recorded which was acoustically analyzed using Praat for frequency and amplitude measures. In general, the frequency measures were highest when talking about sad life event while amplitude measures were highest when producing neutral speech. The HbO and HbT levels were positive and highest during the happy speech manipulation. During the other two speech tasks, the HbO levels were all negative with neutral being the lowest. The HbT levels showed a more complex change. More data are needed to confirm the pre-frontal lobe (de)activation associated with manipulation of affective prosody. This case study will facilitate future research in this line.
Dialect perception in song versus speech
Authors: Walter Maddy , Bengtson Grace , Maitinsky Marcell , Islam Md Jahurul , Gick Bryan
Published: November 2023

Investigations into style-shift in singing led to the proposal of genre-specific musical sociolects [Coupland, 2011, J. of Soc. 15]. Gibson [2019, Univ. of Canterbury Dissertation] demonstrated that style-shift in popular music is automatic. Additionally, Mageau et al. [2019, Phonetica 76] found non-native English speakers have a less perceptible foreign accent while singing than speaking. These findings provide possible behavioral analogues to the differential processing of speech and song. Gibson [2019, UofCanterbury Dissertation] accounts for this using Todd et al’s [2019, Cognition 185] exemplar theory, emphasizing the role of sung and spoken contexts in perception. We investigate the role of musical context in accent identification. 24 participants completed a dialect-identification task of 32 musical clips from two genres with strong sociocultural associations: country and reggae. 16 clips contained the original instrumental-removed vocals, and 16 different clips from the same songs additionally underwent monotonization and rhythm-normalization. Responses to the manipulated stimuli were more varied than the original vocals. Listeners’ judgements may be more closely tied to country and reggae’s sociocultural associations than speech information itself. These findings counter Mageau et al., illuminating a more complex relationship between accent perception, music, and genre. Future work will investigate this for dialect-nonspecific genres and adjust approaches to stimuli manipulation.
Speech enhancement for helicopter headsets: Simulation and implementation on an FPGA platform
Authors: Timmermann Johannes , Ernst Florian , Sachau Delf
Published: November 2023

Clear and effective communication is crucial for the safe operation of aircraft. In helicopters, high levels of noise are generated by the engine, gears, and aerodynamics, which negatively impact speech intelligibility. To address this issue, modern aircraft headsets utilize active noise control (ANC) to reduce noise levels for both the crew and passengers. However, the speech signals captured by these headsets often contain high levels of background noise, thereby hindering internal and external flight communication. This paper introduces a dual microphone dual stage speech enhancement algorithm that combines basic spectral subtraction with a Wiener Filter, enhanced by the a priori and a posteriori signal-to-noise ratio. Audio data from within a helicopter cabin were recorded during a test flight. In a series of simulations, the Wiener Filter implementation is compared to other algorithms based only on spectral subtraction methods. The results are evaluated using established performance measures for speech quality. The Wiener Filter implementation results in the highest speech quality and is, therefore, implemented on an FPGA-platform for validation in a laboratory experiment. The simulations and measurements demonstrate significant improvements in speech quality and, consequently, enhance speech intelligibility using the proposed method.
Vibration damping by maximizing the reactive power of an inertial shaker
Authors: Karl Tim , Sachau Delf
Published: November 2023

Passive and active vibration control is required to reduce noise, prevent damage, or maintain the stability of a structure. Active measures are of particular importance due to their narrowband performance. They use inverted or phase shifted signals to shift the kinetic energy of the vibrating structure to frequency bands where it does not have a negative effect on the sound emission and auditory sensation. In this paper, an active-mass-damper is realized by an inertial shaker as actuator by controlling its current. The power that the active-mass-damper transmits to the vibrating structure is measured by the transmitted force and the acceleration of the point of force application. The control system maximizes the reactive power and, therefore, acts as an active-mass-damper to minimize the vibration of a structure. An arbitrary structure represented by a single DOF mass-spring-damper system which is excited by a modal shaker. An electromechanical model of the inertial shaker is formulated, and a control system is designed. The simulation is validated with laboratory experiments. The experimental results show that the vibration of the structure can be minimized by increasing the reactive power transmitted by the active-mass-damper to the structure.
Simulation of active vibration control of a moving stage
Authors: Guo Zimu , Zhao Sipei , Halkon Benjamin J. , Clemon Lee
Published: November 2023

Active vibration control (AVC) has gained considerable interest due to its inherent adaptability and cost-effectiveness, with its ability to suppress vibrations in the controlled system across various applications. Existing studies focus on the AVC of non-moving systems and usually assume that the vibration signal to be controlled is known and can serve as the ideal reference signal in feedforward control systems. However, in many practical applications, the ideal reference signal is not accessible, and a sensor must be used to detect the reference signal. This can degrade the AVC performance, especially for a moving system. This study, therefore, aims to explore the potential application of piezoelectric stack actuators (PSA) to control the vibration of a moving stage driven by a stepper motor. The secondary path was estimated offline, and vibration data were collected at different moving speeds. The effects of the location of the reference sensor were initially investigated. Then, extensive simulations were conducted to evaluate the performance of different adaptive control algorithms regarding vibration reduction, convergence speed, computational complexities, etc. This research underlines the potential of integrating PSA within a moving system to effectively control its vibration.
Enhancing generalization performance of anomaly detection-based active sonar classifier
Authors: Kim Geunhwan , Hwang YoungSang , Shin Sungjin , Choo Youngmin
Published: November 2023

It is critical to automatically discriminate between target and clutter in developing future unmanned underwater surveillance systems. However, due to similar physical experiences between target echoes and clutter, active sonar classification remains a challenging problem. Recently, a novel anomaly detection-based active sonar classifier, bi-sphere anomaly detection (BiSAD), was proposed, demonstrating improved generalization performance over conventional supervised learning-based approaches. In the present study, we provide a brief overview of active sonar datasets and the BiSAD. Then, we explore modifications to BiSAD, aiming at further improving its generalization capabilities. Through examination using in situ active data, we validate the efficacy of these modifications, showing superior generalization performance compared to conventional supervised learning-based classifiers and the original BiSAD.
Estimation of seabed properties from ocean ambient noise in shallow water: A review
Authors: Ayub Md , Zhang Zhiyong , Boettger Daniel
Published: November 2023

Ocean ambient noise is the sound persisting in the ocean, which includes contributions from natural and anthropogenic sources, such as rain, wind, shipping, and marine mammals. Multiple interactions of the sound with the surface and bottom in shallow water affect the spatial characteristics of ambient noise. Thus, the spatial noise properties, coherence, and directionality of ambient noise depend on the characteristics of the shallow water environment, such as depth, sound speed profile, and seabed sediment properties. Acoustic properties of seafloor sediments can be extracted from ambient noise based on these noise properties using various types of noise data and geo-acoustic inversion methods. This paper presents a review of literature concerning investigations into available methods, the implementations of these methods, and their verification and validation. The efficacy and the applicability of these inversion methods for a wide range of ocean noise data are also examined in this review.
Measurements of Scholte and Stoneley waves in the seabed
Authors: Miller James H. , Potty Gopu R. , Schneider Cecilia , Lin Ying-Tsong
Published: November 2023

As a part of the Seabed Characterization Experiment carried out in May 2022 in the New England Mud Patch, Scholte and Stoneley waves in the seabed were generated by the interface wave sediment profiler (iWaSP), a piezoelectric bender beam transducer. The iWaSP was deployed four times during in May. These waves were received at ranges of 40–100 m by bottom-mounted ocean bottom recorders (OBXs) each equipped with a three-axis geophone and hydrophone. Miller et al. (2023) found the speeds of these interface waves to range from 39 to 133 m/s in the first of the four deployments. This paper described the results of the following three deployments. Following the classification suggested by Wilson (P. Wilson, personal communication, July 15, 2023), the layers consist at least four distinguishable sediment layers. The upper-most is a relatively thin, fluid-like layer (1) of mud. Below that lies more rigid mud (2). Below the mud is a sand layer (3) with a thickness of 10 m. Finally, there lies a half-space layer (4) with a higher density and faster compressional and shear speeds. We conclude that the Scholte waves traveled on the 1–2 interface and the Stoneley waves propagated on the 2–3 interface. [Work supported by ONR Code 322OA.]
If “variable acoustics” are an essential element in the long term success of a venue, how do we instill the importance of both making the appropriate alterations for different programs, and in addition, optimally maintaining these systems – both to management as well as operators?
Authors: Barbar Steve
Published: November 2023

The pandemic has revealed “versatility” as a significant asset for both venues, as well as performers and musicians. The ability to successfully alter and optimize venue acoustics to accommodate a wider range of programming has become an important consideration in the design of performing arts venues. The responsibility of making the changes, however, falls to the venue management—who may not have been included in meetings that determined how such systems should be utilized. Even when management and operators are trained on best deployment, personnel can change over time. If the “worth” of these systems is not conveyed to incoming personnel, they may be underutilized, thus compromising design goals. We will discuss some real world examples of both good and “not so good” deployments of variable acoustics.
Time reversal acoustic focusing in a reverberant room: Elongating a focus, and the effect of head-scattering
Authors: Beringer Peter J. , Cabrera Densil , Lu Shuai
Published: November 2023

Time reversal acoustics (TRA) has tremendous potential for focusing, or sound concentration, in reverberant architectural environments. While TRA provides an inherently simple means of achieving a high degree of spatiotemporal focusing, its appropriateness for listening applications in the built environment is challenged by the need to accommodate a person within a sufficiently large focal area. At its simplest, a reciprocal time reversal focusing system for audible range sound will produce a focus with a spatial spread corresponding to one-eighth of the wavelength, which is inconveniently small for speech frequencies. However, an elongated focus is introduced by deploying a directional impulse response, which can be created with a directional microphone, or synthesized by time-delay-mixing of multiple omnidirectional impulse responses. This paper reports on results of physical experiments conducted in a reverberant room, complemented by finite-different time-domain simulations in which the effect of introducing a head-sized scatterer was investigated.
Assessing Northern Gulf of Mexico Sperm Whale’s (Physeter macrocephalus) time budget using passive acoustic monitoring
Authors: Mathew Naomi , Sidorovskaia Natalia
Published: November 2023

A time budget empirically measures species-specific behavior regarding the time periods spent engaging in a certain behavior. Sperm whales emit phonations categorized as either foraging or socializing, making it straightforward when creating their time budget based on acoustic observations alone. Understanding regional time budgets can help assessing habitat uses, prey availability, as well as identifying short and long-term trends across the population. Furthermore, sperm whales exhibit both high sexual dimorphism as well as sexually regulated group structures. Individualized multi-pulse echolocation click structure allows total body length as well as sex to be estimated. Apart from a case study conducted by McDonald et al., 2017, a long-term time budgets for sperm whales have not been investigated in the Northern Gulf of Mexico (NGoM). The analysis of multi-year archival acoustic data from the NGoM using a sperm whale click detector as well as CABLE software [Beslin et al., JASA (2018)] is presented to infer sperm whale’s time budget and group structures. [Data acquisition for this research was made possible in part by grants from The Gulf of Mexico Research Initiative and BOEM.]
Using the Soundscape Code to compare coastal marine habitats in the Gulf of Maine
Authors: Milne Grant A. , Miksis-Olds Jennifer , Stasse Alyssa , Lee Bo-Young , Wilford Dylan , Baruah Shaurya , Brown Bonnie
Published: November 2023

Identifying similarities and differences in soundscape properties among coastal marine habitats is valuable for determining indicators of habitat composition, assessing functional connectivity among habitats, and informing management decisions regarding the soundscapes of these habitats. The “Soundscape Code,” proposed and developed by Dylan Wilford, enables rapid calculation of values for four salient soundscape properties: amplitude, impulsivity, periodicity, and dissimilarity. This enables multivariate statistical analyses to quantitatively compare soundscapes in different habitat types and geographic regions. The objective of the current work was to determine whether geographic region or habitat type accounts for more variability in coastal soundscape properties. Passive acoustic recordings were acquired in three different habitat types (sand, macroalgae, and eelgrass dominated substrates), in each of four different geographic locations along the New Hampshire/Maine coastline, to compare the soundscapes of habitats with varied biological and geophysical substrate composition. Results indicate that geographic location accounted for more variability in the soundscapes than habitat type, suggesting that habitats’ local connectivity outweighs acoustic and biological uniformity of the same habitat type over broader spatial scales. Future analyses will incorporate metagenomic data for predictive modeling of habitat composition through the combined use of passive acoustic monitoring and metabarcoding of seawater samples.
Natural soundscape variation appears to influence the structure of stereotypic calls and repertoires in killer whales
Authors: Yurk Harald , O'Neill Caitlin , Quayle Lucy S. , Vagle Svein , LeBlond Holly T.
Published: November 2023

Underwater soundscapes show dynamic variations in natural ambient sound levels at different locations and water depths and levels can vary over a course of a day. This soundscape dynamicity may pose a vocal challenge for highly mobile marine mammals whose habitat overlaps with many dynamic soundscapes. The most prominent communication tool of killer whales is a pulsated often multicomponent call which can be detected at more than 15 kilometers under quiet conditions. Social learning of call structure is a driver for stereotypic long lasting group- or population-specific call repertoires. Here we describe the potential vocal adaptations of killer whales to reduce the influence of sound propagation loss (PL) on their calls. Reliable propagation to identify groups and populations at considerable distances is important. In experimental field trials, the PL of killer whale calls and that of tones and sweeps was examined to determine if call component PL differs among soundscapes. PL is positively correlated with spatial and temporal ambient noise level variation. Furthermore, the use of burst pulses, a common feature of calls increased propagation distances at higher noise levels. We conclude that noise variation is one of the drivers of call structure and may also influence the call repertoire size.
Deep clustering analysis for data exploration and anomaly detection in distributed acoustic sensing (DAS) systems
Authors: Jenkins William F. , Chien Chih-Chieh , Gerstoft Peter
Published: November 2023

Distributed acoustic systems (DAS) offer a unique opportunity to sense seismic and acoustic waves at high sampling rates and spatial resolutions using fiber optic cables. The prevalence of fiber optic cables crossing seabeds around the world make them particularly attractive sensors of opportunity for acoustical and geophysical applications. However, the high spatial and temporal resolutions of these systems pose significant challenges to efficient data processing and analysis. To overcome this, we propose a two-step exploratory analysis procedure in which the dimensionality of the data is first reduced into a latent space containing its salient information, and then perform clustering analysis of the data in the latent space. Spectrograms of detected events are encoded into the latent space using a convolutional autoencoder, and clustering is performed using Gaussian mixture model clustering. We demonstrate our technique on experimental data collected from a DAS array deployed at a geothermal energy research site. With this technique, we show a data-driven approach to exploratory data analysis, enabling identification of dominant types of detections in the data and identification and removal of anomalous detections due to instrument noise.
Cerebral microvascular markers of intracranial pressure in acute and subacute porcine hydrocephalus model
Authors: Le David Q. , Zhang Zeng , Karmacharya Mrigendra B. , Sultan Laith , Kilbaugh Todd , Katz Joseph , Hwang Misun
Published: November 2023

Hydrocephalus affects 1.1% of infants, resulting in abnormal accumulation of cerebrospinal fluid and elevated intracranial pressure (ICP). Elevated ICP can occur prior to detectable morphological changes using computed tomography, resulting in delayed diagnosis and treatment. To improve early diagnosis, we propose vascular imaging using ultrasound localization microscopy (ULM) and ultrafast Doppler to measure cerebral blood flow changes due to acute to subacute elevations in ICP. We performed a pre-clinical study on a neonatal porcine model with 30 min, 8 h, 12 h, and 24 h ICP elevations while performing brain ultrasound measurements in hourly intervals. Ultrafast plane-wave ultrasound imaging was implemented using the Verasonics Vantage-256 and GE IC59D curved array probe at 400Hz frame rate. Lumason contrast agent was infused into each animal, providing tracers for ULM and enhancing the ultrafast Doppler imaging. Based on preliminary analysis, ultrafast Doppler showed reduced total cerebral blood volume after acute ICP elevation. ULM showed highly correlated parabolic reductions in cortical microcirculation with increasing ICP. Drastic reductions in cerebral microcirculation but less so in microcirculation accompanied microdialysis evidence of brain ischemia. Additionally, there were spatiotemporal changes in cerebral microvascular flow with varying ICP durations that warrant additional investigations using ultrafast ultrasound imaging.
Developing a focused ultrasound treatment for tendinopathies in a large animal model
Authors: Wood Grace , Elliott Jacob , Simon Julianna
Published: November 2023

Current treatments for tendinopathies produce mixed success rates, with 0-84% of patients showing improvement. Our prior work in rats suggests mild microdamage induced by focused ultrasound (fUS) may perform better than traditional treatments for tendinopathies, like dry needling. Here, we work to scale our work in rats to larger animal models and develop treatment monitoring. Ex vivo bovine digital flexor tendons were obtained and injected with collagenase to induce chronic tendinopathy. One day later, tendons were treated with focused ultrasound at 1.1–3.68 MHz, with 1–10ms pulses at pressures up to p +  = 127 MPa/p− = 35 MPa repeated at 0.2–1 Hz for up to 20 min. Treatments were monitored with passive cavitation detection (PCD; Sonic Concepts Y-107) and Philips/ATL L7-4 controlled by the Verasonics research ultrasound system in passive cavitation imaging (PCI) mode. Samples were collected for histological analysis. Preliminary results suggest that lower pulse repetition frequencies produce mild mechanical microdamage with no evidence of thermal necrosis. PCI and PCD results show no consistent trends to indicate the intended mechanical microdamage bioeffect has been achieved. Work is continuing to determine the treatment parameters that produce the intended bioeffects in the smallest time and to develop a means to monitor treatment progress. [Work supported by NIHR01EB032860.]
Advanced numerical techniques for predicting frequency response functions
Authors: Wu Kuangcheng
Published: November 2023

Numerical methods have been widely used to predict Frequency Response Functions (FRF) of structures. The FRF can be used to characterize structural dynamics and support sound and vibration control. Generally, frequency sweep is conducted in the FRF calculations to identify damping and resonant frequencies of structures under excitations. However, as numerical models are getting complex and larger, the demands for computational resources (e.g., CPU time, memory, disk space) are greatly increased. Lately, high performance computing (HPC) at the DoD HPC center has been used with advanced numerical techniques to reduce the overall computational time. Those advanced numerical techniques include Krylov subspace and Galerkin Projection (KGP) and Pade Approximation. Significantly CPU time reduction has been demonstrated for relatively smaller FE models. This paper will further discuss adaptive KGP by automating the frequency sweep process via calculated relative residues, then combine with Finite Element Tearing and Interconnecting (FETI) to solve for FRF of a large FEM model in the order of 60M DOF. A flat plate with viscoelastic layer will serve as an example to demonstrate accuracy and efficiency of AKGP with FETI. The benefits of using HPC with advanced numerical techniques to solve for large FEM models are clearly displayed.
Fast and accurate boundary element methods for large-scale computational acoustics
Authors: van 't Wout Elwin , Haqshenas Reza , Gélat Pierre , Saffari Nader
Published: November 2023

The boundary element method (BEM) is a powerful algorithm to solve the Helmholtz equation for harmonic acoustic waves. The explicit use of Green’s functions avoids domain truncation of unbounded regions and accurately models wave propagation through homogeneous materials. Furthermore, fast multipole and hierarchical compression techniques provide efficient computations for dense matrix multiplications. However, the convergence of the iterative linear solvers deteriorates significantly when frequencies are high or materials have large contrasts in density or speed of sound. This talk presents several algorithmic improvements of the BEM. First, a preconditioner based on on-surface radiation conditions drastically reduces the iteration count of linear solvers at high frequencies. Second, anovel boundary integral formulation remains well-conditioned for high-contrast transmission problems. We used our fast and accurate BEM implementation to simulate focused ultrasound propagation in the human body, which can be translated to important biomedical applications such as the non-invasive treatment of liver cancer and neuromodulation of the brain. We validated the methodology within the benchmarking exercise of the International Transcranial Ultrasonic Stimulation Safety and Standards (ITRUSST) consortium. As a second application, we simulated the collective resonances of water-entrained arrays of air bubbles. Finally, we implemented all functionality in our open-source Python library, OptimUS.
Multi-fidelity models based on Gaussian processes in acoustic applications
Authors: Gurbuz Caglar , Eser Martin , Marburg Steffen
Published: November 2023

Accurate predictions are generally accompanied with high costs and expenses. As a conesquence, system observations can only be generated for a few samples. The idea of multi-fidelity modeling aims to merge observations from different models of varying complexities and costs. This contribution introduces multi-fidelity models applied to acoustic problems. Therefore, we deploy models with different fidelity levels to treat the frequency-dependent Helmholtz equation. While the spatial solution is acquired with the boundary element method, Gaussian processes are used as surrogates to approximate the system’s response in the frequency dimension. This way, multi-fidelity models are adopted to efficiently approximate the solution of the Helmholtz equation for a certain frequency range. For validation purposes, the low frequency booming noise problem occurring in vehicle cabins is treated. Our findings demonstrate that multi-fidelity models yield an accurate approximation. In addition, the computational costs are reduced when compared with the high-fidelity solution at each frequency. In the sense of a Bayesian technique, multi-fidelity models based on Gaussian processes allow to consider uncertainties. Beyond fast and accurate predictions, the proposed method paves the way for accelerated decision-making processes in early design stages, where uncertainties due to limited information on the model or simplifying assumptions are omnipresent.
Investigating sound absorption in rail tunnels using wave decomposition
Authors: Sepehrirahnama Shahrokh , Oberst Sebastian , Croft Briony E. , Hanson David
Published: November 2023

Acoustic noise in trains is a more prevalent problem in tunnels as compared to open track scenarios. This is mainly due to less acoustic radiation relative to increasing contributions of reflections and reverberation. Sound absorbing panels on a tunnel wall and in the track four-foot perform better above 1 kHz with absorption coefficients larger than 0.8. To investigate sound absorption below 1 kHz, we employ wave decomposition into incidence, reflection and absorption components for a section of a given underground tunnel design. A Finite Element (FE) 2D model of a carriage and tunnel is developed, representing a tangent portion of a rail track and including the noise power spectra from the rail-wheel interactions for three different roughness scenarios. The FE model, compared to a Ray Tracing one, provides precisely imposed boundary conditions and the pressure field of the entire tunnel interior. Our results can identify the performance of current panels, absorbing significantly less noise power in the lower frequency range, especially within the 0.3–0.5 kHz interval. The insights from wave decomposition analysis can lead to solutions to increase absorption by changing the reflection pattern below 1 kHz band, improving the passenger comfort during a longer train ride.
Experimental evaluation of bilateral Ambisonics-based binaural room transfer function synthesis with application to personal sound zones
Authors: Qiao Yue , Choueiri Edgar
Published: November 2023

This study experimentally evaluates the bilateral Ambisonics method for synthesizing binaural room transfer functions (BRTFs) and explores its application in generating personal sound zones (PSZs) around listeners’ ears. Bilateral Ambisonics is proposed for improving the spatial sound reproduction accuracy at a limited Ambisonics order, by shifting the origin of Ambisonics representation from the head center to the two ears. While numerical simulations have demonstrated its superiority over traditional Ambisonics, little attention has been given to validating its usability for reproduction in realistic environments with loudspeakers. Experiments are conducted wherein the BRTFs of a dummy head listener are first synthesized by combining the spatial room transfer functions (SRTFs) measured with a spherical Ambisonics microphone array at the ear position and the corresponding head-related transfer functions (HRTFs), and then compared with the actual in situ measured ones. Furthermore, the quality of the synthesized BRTFs is examined in the context of an in-house PSZ system, by objectively evaluating the performance of PSZ filters designed with such BRTFs in terms of acoustic isolation metrics. The application of synthesized BRTFs to PSZ systems circumvents the need for in-situ BRTF measurements, making it highly feasible to deploy such systems while achieving high acoustic isolation.
Optimizing acoustic contract control target for sound zones in an enclosed space
Authors: Zhu Qiaoxi , Zhao Sipei
Published: November 2023

Acoustic contrast control is fundamental to achieving the highest sound energy difference between listening and quiet zones within a space. While extensively studied in simulations and laboratories, its real-world application has been confined to engineered applications, for example, acoustically treated rooms. However, for a broader application, we notice significant degradation in acoustic contrast performance from the laboratory prototype to the actual room application. To mitigate this disparity, we propose a physically optimized target to enhance room acoustic contrast control. The proposed method is evaluated by offline simulations using real-world room impulse responses.
Active attenuation of free field noise in a spatial domain using neural networks inferred controller
Authors: Kila Ramy , Amirkulova Feruza
Published: November 2023

In this talk, we explore the application of deep neural networks (DNNs) to infer the decoupling of an incoming acoustic array, distinguishing between the signal of interest and noise components. The objective is to leverage this decoupling information to develop an effective controller that can attenuate the noise, thereby improving the quality of the desired signal. The decoupled noise is then fed into a specially designed controller to attenuate the noise while preserving the desired signal. The controller leverages the DNN's predictions to adaptively adjust its parameters, allowing it to adapt to changing noise conditions and improve noise reduction performance. The approach is evaluated using simulations and real-world acoustic array measurements. The results demonstrate the performance of the DNN-based decoupling and noise attenuation system in reducing noise while preserving the quality of the desired signal. The proposed system offers effective adaptive solutions for enhancing the quality of desired signals in the presence of noise, with potential applications in areas such as speech recognition, audio communication systems, and environmental noise suppression.
Investigating the sonic characteristics of New Zealand’s Indigenous instruments: taonga pūoro and miheke oro (Māori and Moriori musical instruments)
Authors: Cattermole Jennifer
Published: November 2023

This paper investigates the sonic characteristics of taonga pūoro from a performer’s perspective, as well as on how the instruments’ construction and materials affect their sound. It also presents findings from two recent projects that involved making 3D printed models of Indigenous instruments. The first included taonga pūoro from the Otago Museum, and the second the only two known Moriori flutes (held in the Bishop and Canterbury museums). These were CT scanned, and that data used to create digital models, which were printed. The first project utilized one type of print media, whereas the second utilized several. Because playing the museum instruments is not permitted, other instruments have been used as controls to test the prints’ sonic properties – a kōauau (a type of Māori flute) held by the University of Otago in the first project, and replicas of Moriori flutes made from albatross bone (the flutes’ original material) in the second. Recorded.wav files of both the original and printed replica instruments were compared using the application Izotope Rx5. This application enables sound files to be viewed as spectrograms, allowing for the harmonic and resonant content of the recordings to be compared visually.