bluuebunny/crossref_metadata_2025 huggingface dataset:
Convolutional neural networks for signal identification and extraction and seabed classification
Authors: Olson Wesley E. , Neilsen Tracianne B. , Knobles David P. , Sagers Jason D. , Wilson Preston S.
Published: July 2024

Sound underwater source (SUS) charges can be used for seabed characterization experiments. Many SUS were deployed during experiments in the New England MudPatch during 2017 and 2022. The goal of this work is to automatically detect and extract SUS signals in the dataset and then perform seabed classification on the extracted SUS signals. A binary classifier CNN is trained on simulated SUS charges and measured ambient noise to detect if a SUS signal is present in one minute pressure waveforms. The trained CNN model is then used to identify and extract the SUS signals from the measured data on the 52-channel PROTEUS L-array deployed by Applied Research Laboratories, University of Texas at Austin. This automated extraction process expedites the identification and time alignment of hundreds of SUS signals. The extracted signals will then be input to a ResNet-18 network trained on synthetic signals to perform seabed classification using a catalog of 34 seabeds. Lessons learned from the automated identification and extraction process will be presented as well as a statistical analysis of the seabed classification results. [Work supported by the Office of Naval Research, Grant N00014-22-12402.]
Evaluating the measurement of the velocity level difference for building constructions which combine Type A and Type B elements
Authors: Mahn Jeffrey , Mueller-Trapet Markus , Skoda Sabrina , Cunha Iara B.
Published: July 2024

The standard ISO 12354 outlines a method of predicting the transmission of structure-borne noise in buildings based on data measured in a laboratory or in the field, measured in part according to the standard ISO 10848. The ISO 10848 standard describes procedures for the measurement of both the normalized flanking level difference and the velocity level difference of flanking paths through different building constructions and the junctions between them. Both the normalized flanking level difference and the velocity level difference were measured for a hybrid construction of a cross-lamented timber floor (Type A element) connected to lightweight timber walls (Type B elements) in the National Research Council Canada’s four room flanking facility. The predicted normalized level differences are compared against the measured values to evaluate the prediction method for constructions that mix Type A and Type B elements.
A meta-analysis of sound isolation properties of various modular prefabricated wall systems
Authors: Latour Jean-François
Published: July 2024

The current meta-analysis focuses on airborne sound isolation performances for modular prefabricated wall panels. As many properties may be varied in prefabricated wall assemblies, relying only on measurements either on prototypes in a lab or in situ tests would require a significant amount of resources. Understanding the precision and limitations of theoretical evaluation methods is, therefore, a must. A comparison of theoretical predictions with lab and field measurements (as per ASTM E90 or E336) is performed on multilayer systems up to a double wall panel system which incorporates four layers (two panels each composed of two layers). This allows a better appreciation of theoretical predictions of modular prefabricated wall systems.
Robust 3D localization of anomalies in reverberation time measurements using the sound field scanning method
Authors: Rittenschober Thomas , Karrer Rafael
Published: July 2024

Reverberation time measurements form the basis for room acoustic optimizations of existing building structures. During the verification of the achieved room acoustic improvements, anomalies may appear in the reverberation time signal which may be hard to spatially localize, especially in spaces with demanding acoustic requirements such as large, open workspaces, or concert halls. This contribution focuses on the application of the Sound Field Scanning technology to the fast spatial localization of room reflections. In this process, an omnidirectional sound source is positioned at an observation point in the room and periodically excited with band-limited pulses. At the same observation point, an acoustic camera system consisting of a rotating linear microphone array is oriented towards the preferred spatial direction. The emitted pulses and associated room reflections are captured on the measurement surface of the rotating microphone array. Acoustic images with high depth resolution are generated in parallel planes to the measurement surface. In complex situations, the task of spatially localizing anomalies in the reverberation time signal can be reduced to a few measurements from different viewing angles, thus, significantly accelerating the problem-solving process with high confidence. The method is exemplarily described through the room acoustic analysis of a University Lecture Hall.
Real-time assessment of focused ultrasound-induced bioeffects in elastic tissues
Authors: Elliott Jacob C. , Wood Grace M. , Simon Julianna C.
Published: July 2024

Highly elastic tissues have proven resistant to fractionation via focused ultrasound (fUS); however, our previous work in rat tendon has demonstrated a small window of parameters conducive to mild mechanical disruption. For therapeutic applications, there is a need to assess the extent of fUS-induced mechanical bioeffects in real time in order to avoid over- or under-treatment. Here, elastic collagen hydrogels (TeloCol®-10), as well as healthy and collagenase-soaked ex vivo bovine tendons, were exposed to fUS at 1.1–3.68 MHz (p + ≤ 127 MPa, p− ≤ 35 MPa) using 10-ms pulses repeated at 1 Hz. Cavitation signals were collected using simultaneous passive cavitation imaging (PCI) and passive cavitation detection (PCD) to monitor fUS treatment in real time. Preliminary data in polyacrylamide hydrogels and ex vivo bovine tendon show no consistent trends between simultaneous PCI and PCD signals; this is potentially due to different orientations of the receiving transducers, which we will further investigate. However, neither PCI nor PCD trends were consistently linked to a mechanical bioeffect. Therefore, we are exploring the addition of Doppler ultrasound to PCI/PCD to help link the fUS exposure to the desired bioeffect. [Work supported by NIHR01EB032860]
A spectral Doppler ultrasound method for estimation of skeletal muscle velocity
Authors: Suitor Elizabeth L. , Jin Yichu , Cerasi Sofia , Howe Robert D. , Walsh Conor J.
Published: July 2024

Skeletal muscle velocity is a key indicator of neuromuscular function, and monitoring its changes plays important role in tracking the progression of musculoskeletal diseases, injuries, and fatigue. However, existing methods for non-invasive estimation of skeletal muscle velocity primarily use B- mode ultrasound, often with processing methods that are time-consuming or computationally expensive, with varying accuracy based on tissue structure. Here, we propose a spectral Doppler envelope estimation method designed for skeletal muscle measurements. When compared to the modified signal noise slope intersection (MSNSI) method, our method reduces the overall mean absolute error by 13.9% and the mean absolute zero error by 82.1%. We validated our method using a portable ultrasound system on a benchtop setup that mimics the acoustic properties, measurement angles, and velocity patterns of skeletal muscles. Ex vivo and in vivo muscle velocity estimates of parallel and pennate muscles will be compared to those obtained using the MSNSI method and manual tracking of B-Mode images. Our proposed method could enable automated estimation of skeletal muscle velocities during dynamic activities in unconstrained environments, providing new insight into neuromuscular function and movement biomechanics, with potential applications in monitoring fatigue, disease progression, or injury recovery. [Work supported by the National Science Foundation.]
Nonlinear imaging-based bubble cloud size estimates compared with histotripsy treatment zone: An in vitro study
Authors: Trivedi Vishwas , Bader Kenneth B. , Shekhar Himanshu
Published: July 2024

Volterra filtering combined with subharmonic imaging was previously reported to enhance the visualization of the histotripsy bubble cloud. In this study, we compared the bubble cloud size obtained by imaging to the histotripsy ablation region using receiver operating characteristic (ROC) analysis. Histotripsy was performed in a red blood cell (RBC)-doped agarose phantom using a 1 MHz transducer. Ultrasound imaging data was acquired using a C5-2V probe and chirp-coded excitation (bandwidth: 2–5 MHz). These ultrasound acquisitions were then processed by subharmonic (SH) matched filtering alone, SH with quadratic Volterra filtering, and SH with cubic Volterra filtering. The therapy pulse and imaging sequence were interleaved (N = 100 frames), and a video camera was used to visualize the damaged region. A mean bubble cloud image was generated across all treatment sequences and co-registered with the camera image. A ROC curve was formed using binary classification of the mean bubble cloud versus the ablation zone, and the area under the ROC curve was determined. Filtering by quadratic and cubic Volterra filters reduced artifacts significantly [over 20 and 30 dB contrast-to-tissue enhancement (p < 0.01), respectively], along with achieving a high area under the ROC curve (0.97). These findings highlight the potential of Volterra filtering for histotripsy guidance.
Reconstruction methods for super-resolution imaging with PSF modulation
Authors: Lu Jian-yu
Published: July 2024

Recently, a super-resolution imaging method called the PSF (point spread function) modulation method was developed (Lu, IEEE TUFFC 2024). In this method, the amplitude, phase, or both of the PSF of a linear shift-invariant (LSI) imaging system is modulated so that the modulated PSF has a higher spatial frequency than that of the original PSF to reconstruct super-resolution images. The modulator can be produced and manipulated remotely by methods such as radiation force or it can be a physical particle such as micro- or nano-particle manipulated by an external force such as electrical and electromagnetic force. In principle, the super-resolution imaging method can be applied to any LSI imaging system, such as ultrasound, optical, photoacoustic, electromagnetic, underwater, nondestructive evaluation (NDE), and magnetic resonance imaging (MRI) system. These include pulse-echo ultrasound imaging, transmission imaging, wave source/field imaging, acoustical camera, and optical bright-field microscope. To optimize the quality of the images, methods for the reconstruction of pulse-echo and wave source/field super-resolution images are studied and the results will be presented. These methods include the uses of an analytic envelope of radio-frequency (RF) signals with and without windowing, “I” (in-phase) and “Q” (quadrature) signals, and the DC (direct current) component removal.
Use of metamaterials to reduce underwater noise generated by ship machinery
Authors: Vulliez Mathis , Guy Marc-André , Kesour Kamal , Marquis Jean-Christophe G. , Catapane Giuseppe , Petrone Giuseppe , Robin Olivier
Published: July 2024

Reducing underwater noise pollution from ship machinery is a significant challenge. Ship machinery usually operates at fixed speeds and emits tonal noise with large amplitudes at low frequencies. Conventional soundproofing materials are inadequate for absorbing tonal noise and require large thicknesses at low frequencies. Quarter-wavelength resonators effectively absorb sound at their fundamental frequency and odd harmonics. Still, the applicability of this solution is nevertheless limited by its length requirement, which becomes cumbersome at low frequencies and, thus, large wavelengths. This study explores different structured metamaterial designs based on labyrinth, coiled quarter-wavelength resonators, and hybrid configurations combining glass wool and coiled resonators. Analytical, numerical calculations, and experimental tests are carried out under normal plane wave incidence (using an impedance tube) and a diffuse acoustic field (in a small reverberant cabin). In particular, a numerical optimization based on a periodic unit cell model is used to optimize the hybrid configuration and analyze its behavior under variable plane wave incidence angles. Preliminary tests conducted in a water basin using a small, straightforward aluminum box equipped with some proposed designs indicate reductions in underwater noise levels. The proposed solutions offer limited-cost and compact solutions for mitigating machinery noise and, potentially, the preservation of marine ecosystems.
Sound designing classical guitars through metamaterials
Authors: Bader Rolf , Kontopidis Patrick
Published: July 2024

An approach is presented to alter the sound of a classical guitar using a metamaterial structure. By adding additional masses using magnets in a row between the bridge and the soundhole, a bandgap of around 300 Hz appears. Alternation of magnet masses and placement determine the location and strength of the bandgap. A similar approach was presented with a frame drum [R. Bader, J. L. Fischer, M. Münster, and P. Kontopidis, “Metamaterials in musical acoustics: A modified frame drum,” JASA 145(5), 3086–3094 (2019)]. There, the lower and upper limits of the bandgap are caused by the relations between the frequency wavelength and the magnet distances. With the guitar, the bandgap is caused by a shifting and attenuation of modes. Interestingly, the added masses cause a decrease in the guitar top plate mode frequencies, which is similar to membrane behavior and contrary to the expectancy of a plate. Such a guitar sound is unique due to the strong bandgap and cannot be achieved with typical alternations of changed fan bracing or top plate thickness. Magnets can easily be applied by guitarists within minutes and, therefore, qualify as a guitar sound design chosen by players.
Experimental assessment of playability limits during bowed string attacks
Authors: Lampis Alessio , Mayer Alexander , Chatziioannou Vasileios
Published: July 2024

The playability limits in the bow force and bow acceleration parameter space (usually visualized as a Guettler diagram) define the conditions for establishing Helmholtz motion during bowed attacks in bowed-string instruments. Despite few theoretical and numerical studies, there is little empirical validation of these limits. The experimental scanning of a Guettler diagram is a tedious process, as it requires the use of a bowing machine to control the bowing parameters. This study proposes a method for collecting and analyzing data to produce measured Guettler diagrams. Experiments were conducted using a cello string in a monochord arrangement with fixed terminations. The string was excited using a robotic arm that allows control of the playing conditions by changing the bow force and bow acceleration. Each set of measurements contains more than 900 data points to obtain high-resolution Guettler diagrams. In addition, the measurements are repeated in reverse order and after dismounting and remounting the string. The results are compared with existing literature, with particular attention to theoretical limits. The experimental results suggest that the static and dynamic friction coefficients vary with bow force and acceleration, modifying the playability limits. [Work supported by the Austrian Science Fund (FWF) (P34852-N).]
Towards reproducing bowed-string instrument transients using physical modeling
Authors: Matusiak Ewa , Chatziioannou Vasileios
Published: July 2024

Physical models of bowed-string instruments can forecast various aspects of bow-string interaction. However, accurately replicating transient waveforms of string oscillations remains a challenge. In this work, measured transient behavior of the bowed string is compared with predictions from a simulation model. Fixed boundary conditions are assumed and a finite-width bow, bow-hair compliance, torsional string motion, and an elasto-plastic friction model are incorporated. The latter links relative velocity and friction force through a differential equation, and therefore, exhibits hysteresis behavior. Simulated Guettler diagrams are then compared to measured ones obtained from a robot bowing a monochord. The general shape of the playability region is successfully predicted, but some details in the measured time-domain waveforms are not reproduced by the model. Employing inverse modeling, parameter values for the elasto-plastic friction model are derived, demonstrating the ability to generate reliable reconstructions of the measured transient signals. These results emphasize the need to account for variable friction coefficients in order to reproduce measured signals. This observation aligns with prior findings indicating that static and dynamic friction coefficients vary with bow force and bow acceleration. [Work funded in whole or in part by the Austrian Science Fund (FWF) (P34852-N).]
Variation of Falcon 9 noise at far-field recording sites
Authors: Pulsipher Noah , Moats Levi T. , Gee Kent L. , Hart Grant W. , McCullah-Boozer Megan R. , Hall Lucas K.
Published: July 2024

The rapid launch cadence of SpaceX’s Falcon 9 rocket provides the opportunity to study the relative consistency of far-field noise propagation. Acoustical measurements of several Falcon 9 launches have been made on and near Vandenberg Space Force Base at a far-field location 8.4–14 km from the pad. This paper compares collocated measurements from different Falcon 9 missions to begin to understand data variability as a function of launch and environmental conditions at far-field locations. The 8.4 km location has been measured over 10 times, whereas other locations span subsets of launches. This comparative analysis includes time-varying levels, spectra, and waveform statistics, such as the pressure derivative skewness. Time periods of particular interest are liftoff, peak noise, and late into the launch when the vehicle is significantly downrange. [Work supported by USACE.]
Variation of Falcon 9 noise in the mid-field
Authors: Moats Levi T. , Pulsipher Noah , Gee Kent L. , Hart Grant W. , McCullah-Boozer Megan R. , Hall Lucas K.
Published: July 2024

The rapid launch cadence of SpaceX’s Falcon 9 rocket provides the opportunity to study the relative consistency of noise radiation. Acoustical measurements of several Falcon 9 launches have been made on and near Vandenberg Space Force Base within 1 km of the launch pad. This paper compares collocated mid-field measurements from different Falcon 9 missions to begin to understand data variability as a function of launch and environmental conditions. One location 395 m from the pad has been measured over 5 times. This comparative analysis includes time-varying levels, spectra, and waveform statistics such as the pressure derivative skewness. Time periods of particular interest are liftoff, peak noise, and late into the launch when the vehicle is significantly downrange. [Work supported by USACE.]
Designing an acoustical test fixture to evaluate the objective occlusion effect
Authors: Doutres Olivier , Luan Yu , Cyr-Desroches Marc-Olivier , Carillo Kévin , Richert Robin , Sgard Franck
Published: July 2024

Earplugs are commonly used to prevent noise-induced hearing loss. However, their effectiveness is often hindered by the discomfort they cause, impacting consistent and correct use. An important acoustical discomfort, known as the occlusion effect, arises from an increased perception of bone-conducted physiological sounds (such as one's own voice, breathing, and chewing) when the ear canal is occluded. To objectively assess this discomfort, the study proposes the use of an acoustical test fixture (ATF) that avoids direct measurements on human participants. The ATF employs an anatomically realistic truncated outer ear, incorporating soft tissues, cartilage, and bone components to replicate the outer ear's bone conduction path, crucial for occlusion effect assessments. The study demonstrates that the proposed ATF can replicate key effects observed in objective ccclusion effect (OE) measurements on human participants, including significant OE at low frequencies diminishing with increasing frequency, reduction of OE with greater insertion depths, and distinctions among various earplug types—especially noticeable at deeper insertions. Furthermore, a computationally efficient finite element method-based virtual tester for the ATF is developed and validated.
Influence of reference transducer location on hearing protector attenuation metrics for impulse noise
Authors: Murphy William J. , Tasko Stephen M. , Flamme Gregory , Deiters Kristy K. , Meinke Deanna K. , Finan Donald S. , Lankford James E. , Stewart Michael
Published: July 2024

The ANSI/ASA S12.42-2010 standard can be used to estimate the attenuation for impulsive noises between 130 and 170 decibels peak sound pressure level (dB pSPL). The ANSI/ASA S12.42 method uses a complex transfer function between the signal received in the ear of an acoustic test fixture (ATF) and a reference transducer. The reference transducer is at the same radial distance from the impulse source and at less than 30 degrees from the ATF angle. The reference transducer is specified as a pencil-type pressure (> 40.6 cm long). The maximum angle and the minimum pencil probe dimensions could be incompatible near the source, or may introduce artifacts or hazards. In this study, several hearing protectors were evaluated with two rifles (A-Bolt .300 Winchester Magnum and Colt AR-15 5.56 caliber), two ATFs (GRAS 45CB), and five transducers (four ¼” microphones and one surface mount microphone). The ATFs were on opposite sides of the gun at distances for field levels between 180- and 140-dB pSPL. For each location and rifle, S12.42 metrics were calculated for all 20 combinations of ATF ear and reference transducer. Results indicated that S12.42 metrics were minimally affected by the locations of the reference transducers.
Tubes among us: Analog attack on automatic speaker identification
Authors: Fawaz Kassem , Ahmed Shimaa
Published: July 2024

Recent years have seen a surge in the popularity of acoustics-enabled personal devices powered by machine learning. Yet, machine learning has proven to be vulnerable to adversarial examples. A large number of modern systems protect themselves against such attacks by targeting artificiality, i.e., they deploy mechanisms to detect the lack of human involvement in generating the adversarial examples. However, these defenses implicitly assume that humans are incapable of producing meaningful and targeted adversarial examples. In this paper, we show that this base assumption is wrong. In particular, we demonstrate that for tasks like speaker identification, a human is capable of producing analog adversarial examples directly with little cost and supervision: by simply speaking through a tube, an adversary reliably impersonates other speakers in the eyes of ML models for speaker identification. Our findings extend to a range of other acoustic-biometric tasks such as liveness detection, bringing into question their use in security-critical settings in real life, such as phone banking.
The infrasonic choir: Decoding songs to inform decisions
Authors: McComas Sarah
Published: July 2024

The world around us is continuously evolving due to the actions of Mother Nature and anthropogenic activities, which impacts the decisions made on how we interact with the environment. Many of these changes are observable by listening to the infrasonic choir around us everyday. The voices of the infrasound choir include a wide variety of both natural (e.g., surf and volcanic activity) and man-made ( e.g., explosions and infrastructure) sources. Understanding how to exploit the infrasonic song to make sense of the environment in near-real-time is the focus of ongoing research. An example of this is listening to infrastructure (bridges and dams) for insights into structural health, which can be utilized to prioritize limited resources after a natural disaster (hurricane or earthquake). This presentation explores operationalizing this capability, such as how to monitor source rich urban spaces, re-envisioning sensing in these environments with the development of lightweight/low-cost sensors and mobile arrays, and developing detection, classification, and localization methods for near-real-time processing. When successful, continuous monitoring of the infrasonic choir can provide a method for understanding the environment to inform decisions. Permission to publish was granted by the Director, Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center.
Infrasound analysis of the 2018-Dec-18 49 kiloton Bering Sea bolide: Misassociations and celerity-range models
Authors: Grant Bethany , Nippress Alexandra , Green David N.
Published: July 2024

Automatic detections at the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) are often misassociated. This occasionally leads to single events being split into multiple events. Infrasound signals generated from a large bolide over the Bering Sea on 2018-Dec-18 were recorded on more than 15 of the CTBTO International Monitoring System (IMS) stations. The bolide was also reported by the Center for Near Earth Object Studies (http://cneos.jpl.nasa.gov/fireballs) with a calculated total impact energy value of 49 kt. Signals from this bolide were automatically detected and associated at the IDC, into two different events, with the origin time differing by approximately 7.5 minutes and location by ∼125 km. To investigate why detections from this bolide event were misassociated in the automatic bulletins, we analyze infrasound observations from the IMS infrasound arrays and compare our arrival time observations to the automatic detections from the IDC. We use the Bayesian Infrasonic Source Localisation method and employ different celerity-range models, to investigate signal association for this event. Through comparison with the associations based on IDC detections, we aim to improve our understanding of the causes of misassociations and identify potential improvements to future event association algorithms.
Incorporating minority perspectives into study design
Authors: O'Neill Erin , Wu Walter Yueh-Hsun , Nelson Peggy
Published: July 2024

The vast majority of auditory research in the field of hearing loss is conducted by scientists and clinicians with normal hearing sensitivity. As a result, well-intentioned study and survey designs often miss the mark in representing the disabled experience and quantifying outcomes that are meaningful to those with sensory loss. This underscores the importance of supporting the development and inclusion of scientists with sensory loss in academia. In this talk, we will give examples of studies from vision and hearing loss that were designed by disabled researchers. We will focus on how they differ from those designed by non-disabled scientists in the same field. These examples will highlight how the lived experience of scientists with sensory loss influences the types of research questions asked and metrics used to answer these questions. We will also share methods and data from studies that have successfully incorporated the perspectives of hearing- and vision-impaired individuals into their design process.
The collapse of the Tacoma Narrows bridge-- Why?
Authors: Unruh William
Published: July 2024

In 1940, a new bridge over the Tacoma Narrows south of Seattle went into violent oscillation for over an hour and then collapsed, with the loss of one dog's life. The bridge satisfied all of the engineering standards but the first windy day doomed it. What happened? A variety of explanations have been advanced, but the cause turned out to be quite simple, though unexpected. (It was not resonance.) There are many similarities between it and the fundamental playing behaviour of wind instruments, a positive feedback mechanism coupling the bridge to the wind. (It was not resonance.) In 2006, Daniel Green and I, using a finite element program of G. Morgenthal, showed what triggered this positive feedback mechanism in the case of the bridge, and this talk will discuss the features of our explanation
Learning from failure: An analysis of a flawed nonlinear acoustic metamaterial design
Authors: Muhlestein Michael B. , Dunn Kyle G. , Ochi Gordon M. , Swearingen Michelle E.
Published: July 2024

Acoustic metamaterials (AMMs) are structured systems designed to exhibit specific, often exotic, effective material properties for acoustic wave motion. Most research on AMMs prioritize linear wave behavior, but a growing body of work has focused on nonlinear phenomena. While the primary approach to enhancing the nonlinear response of a system has been to place highly nonlinear inclusions in the system (such as bubbles, cracks, or buckling beams), an alternative approach is to control the linear material properties to enhance the relative strength of the nonlinearity. For example, one may reduce the shock formation distance of a system by reducing the effective mass density and wave speed even if the coefficient of nonlinearity is left unchanged. However, due to the nature of nonlinear waves, developing a practical design to accomplish this control can be challenging. We recently designed and built an experimental nonlinear AMM and found it to be fundamentally flawed. In this paper we discuss the thought process that led to the flawed design and present the lessons learned from an unsuccessful experiment.
The effects of delay on task-based interactive conversation
Authors: Masters Benjamin , MacDonald Ewen
Published: July 2024

Previous studies have found that, in the presence of noise, the distribution of floor transfer offsets (FTO) broadens and shifts to the right, and it has been suggested that this is due to increased listening effort. The present study investigates if speakers are sensitive to the timing of the start of a partner's turn during interactive conversation. By manipulating the delay on the channel between two talkers on a turn-by-turn basis, the floor transfer offset (FTO) distribution can be modified to simulate what has been observed in more challenging conversational settings. Talkers were seated in different rooms but could communicate via headset microphones and headphones with gains fixed such that the levels would simulate the two talkers sitting in the same room. Conversations where pairs of talkers solved the DiapixUK spot-the-difference task were conducted in both quiet and noise, both with and without added delay. Measures of speech production (e.g., speech level, articulation rate, etc.) and conversation behavior (FTO, turn length, etc.) are compared across the conditions.
Sound insights: The potential of hearables for early detection and continuous monitoring of Alzheimer’s disease
Authors: Boutros Miriam , Niemczak Christopher , Bouserhal Rachel
Published: July 2024

Early identification using non-invasive biological markers is crucial for detecting and treating Alzheimer's disease (AD). Hearables are intra-aural wearable devices equipped with in-ear microphones capable of capturing inner body signals, including heartbeat, breathing, and blinking. These non-verbal audio events give valuable insight into the individual's physiological state, offering a unique method to detect and monitor subtle changes in the body, which holds the potential for early disease detection. Central auditory (CA) tests, such as understanding speech in background noise, have shown promise in tracking AD’s effects on the central nervous system. They also provide sensitive, quantitative, and repeatable assessments over time. Therefore, this study will assess physiological signals captured by a hearable during central auditory assessment. Thirty-five participants with AD and mild cognitive impairment will be recruited, in addition to age-matched control participants. Hearables will be used to capture physiological data and perform CA tests such as hearing in noise test, triple digits test, dichotic digits test, and dichotic sentence identification test. Moreover, a picture description task, where participants will have to produce coherent speech that holds potential for tracking the decline in cognitive abilities, will be administered. The data collected will be used to build an open-access database serving as the foundation of future research on early detection and monitoring of AD using hearables.
The role of gradient speech categorization in accent perception
Authors: Kutlu Ethan , Peters Emerson , Chiu Samantha , McMurray Bob
Published: July 2024

A key question in speech perception research is how listeners categorize highly varied signals into discrete units. The long-held assumption was that listeners discard variation and focus on the category itself (categorical perception, Liberman et al., 1957). However, listeners often encounter highly varied speech signals (e.g., processing unfamiliar accents). In such cases, discarding variation can be detrimental for listeners and can lead to more processing difficulty. Here, in an ongoing online study (n = 80), we measure English-speaking adult listeners’ speech categorization patterns with a continuous measure (the Visual Analogue Scaling Task: Kutlu et al., 2022; Apfelbaum et al., 2022) to see whether they are more susceptible to phonetic variation in their language environments. We index adults’ language exposure with an extensive social network survey which quantifies the extent to which they are exposed to varied accents on a regular basis and what those accents are. We then asked participants to recognize spoken sentences from a diverse set of unfamiliar accents. We predict that adults who are more gradient in their speech categorization are more accurate in transcribing sentences with a diverse set of accents.
Contribution of positive affect in infant directed speech: what do amplitude modulations patterns suggest?
Authors: Moradi Samin , Polka Linda
Published: July 2024

Speech perception relies heavily on cortical entrainment of amplitude modulations in speech, which occur at different rates. Following a study by Leong et al. (2017) showing slower modulations have higher power than faster modulations in infant directed speech (IDS), we hypothesized that positive emotions in IDS might drive this pattern. Using the same analyses (spectral amplitude modulation phase hierarchy method and phase synchronization index (PSI) (Leong and Goswami, 2015)), we compared the power of isolated modulation rates (synchronous with neural oscillations) and the synchrony between them in IDS and adult directed speech (ADS), using English stimuli from Many Babies Consortium (Frank et al., 2020). We repeated the same analyses comparing happy and neutral ADS using stimuli of four native English speakers (Pell et al., 2009). Our analysis did not uncover significant power differences between IDS and ADS. However, it revealed happy ADS has higher power at slower rates, with the reversed pattern for neutral ADS (p < 0.001). PSI was higher for two faster rates in neutral ADS (p < 0.0001), as reported by Leong et al. comparing IDS versus ADS. These findings reveal novel acoustic features of vocal emotions that might be important in attracting infant attention to IDS.
The effect of age of acquisition on listening effort: Pupillometry and subjective measures
Authors: Carraturo Sita , Van Engen Kristin J.
Published: July 2024

Bilinguals typically perform worse on speech-perception-in-noise relative to monolinguals, and bilinguals who learned the language later typically perform worse than those who learned it earlier. This decrement in performance has largely been attributed to the fact that both bilingualism and later acquisition result in comparatively less exposure to a language than monolingualism and earlier acquisition do. Though this effect of age of acquisition has been well-documented for speech recognition accuracy, less is known about how it affects listening effort. This study quantifies listening effort using three measures (pupil dilation, subjective effort ratings, and subjective fatigue ratings) for four listening conditions (quiet, easy, moderate, and hard). We collect these measures from four groups of participants: monolinguals, simultaneous bilinguals, early sequential bilinguals, and late bilinguals. Data collection is ongoing for a target sample size of 128 (32 per group). Based on related work, we expect greater listening effort for listeners with later ages of acquisition (e.g., late bilinguals relative to simultaneous bilinguals), and for that effect to increase with worsening acoustic quality (i.e., the hard relative to the easy condition). Preliminary results (N = 56) support these hypotheses. These data provide foundational insights into the relationship between bilingualism and listening effort.
An asymptotically exact estimate of the median noise eigenvalue of sample covariance matrices
Authors: Zhuang Yongjie , Anchieta David C. , Buck John R. , Singer Andrew C.
Published: July 2024

The Dominant Mode Rejection beamformer [Abraham & Owsley (1990)] averages the noise subspace eigenvalues of the sample covariance matrix (SCM) to estimate the background noise power. This noise power estimate from snapshot deficient SCMs can be unreliable for large arrays in time-varying environments with limited snapshots. Median filtering offers robustness to outliers and subspace mismatch for these challenging problems. Recent numerical experiments [Campos Anchieta & Buck (2022)] identified a simple regression relating the median sample eigenvalue to the true background power for snapshot deficient SCMs. However, the complicated expression of the Marchenko-Pastur (MP) distribution for the noise eigenvalues of the SCM thwarted prior attempts to find a closed form estimator for the MP distribution median. This talk exploits a coordinate transform to obtain a closed-form median of the MP distribution that is exact for the leading term in the power series expansion of the distribution. The new median estimator is more accurate than the previous numerical regression when the ratio of sensors to snapshots is 2 or more. Given the central role of SCM eigenvalues in principal component analysis and constant false alarm rate detectors, the new median expression should find application in other data science algorithms for underwater acoustics. [Work supported by ONR Code 321US.]
Trampolines and insulation and data, Oh My!
Authors: Keefe Joseph
Published: July 2024

This presentation will discuss sound and vibration data gathered for two separate and unrelated acoustical consultations. The first is a consultation for an adventure park facility (trampolines, arcade games, ball pits, etc.) planned on the upper level of an existing mall; acoustical concerns included vibration from jumping on trampolines and noise from amplified music to adjacent tenant spaces. The second is a comprehensive set of sound level reduction measurements in accordance with ASTM E336 / ASTM E2235, as well as ASTC calculations in accordance with ASTM E413; these results facilitated an investigation of the effect of complete versus partial cavity insulation within partitions.
A primer on terrestrial passive acoustic monitoring data management: Best practices and guidelines
Authors: Clink Dena J. , Pelkie Chris , Charif Russell A. , Klinck Holger
Published: July 2024

Recent advances in recording technology and data storage capabilities have revolutionized how we monitor vocal animals and their habitats. Recently, there has been an explosion of interest in the use of terrestrial passive acoustic monitoring (PAM) which relies on autonomous acoustic recording units (ARU), but terrestrial PAM studies are limited by a lack of standardized protocols for data collection, analysis, and archiving. Here, we draw on collective experiences of recording, analyzing, and archiving, hundreds of years of PAM data to provide guidelines and recommendations for PAM practitioners. First, we highlight some of the major pitfalls in field data collection, including inappropriate recording settings for the research question and incomplete metadata. We then provide recommendations for data management, including suggestions for backing up, compressing, and archiving the data. Our goal is to provide the community with standardized working guidelines that will help facilitate comparative, large-scale terrestrial studies using PAM.
From sounds to science on public lands: Using emerging tools in terrestrial bioacoustics to understand national park soundscapes
Authors: Balantic Cathleen
Published: July 2024

The National Park Service manages over 400 units across the United States, each with unique resource protection needs. Many parks have natural resource conservation priorities that include the protection of natural soundscapes and the sound-producing species who contribute to them. It is challenging, however, to translate terabytes of raw audio into applied information for the diverse research and management questions posed by individual parks. Recent advances in terrestrial bioacoustics are making this process more tractable, particularly as BirdNET has emerged as an extensible off-the-shelf tool equipped to detect diverse assemblages of sound-producing species across varied park ecosystems. We illustrate the applied utility of using and adapting this emerging tool in combination with open code and visualizations to answer multi-taxa questions about occurrence, phenology, and wildlife responses to management. This work demonstrates both the iterative nature and challenges inherent to keeping a federal agency astride the leading edge in a rapidly progressing, data-heavy field, amid a backdrop of global change.
Kauai Beacon receptions and analysis with open-access hydrophones in the North Pacific Ocean
Authors: Ragland John , Durofchalk Nicholas , Dall'Osto David , Gemba Kay L. , Abadi Shima
Published: July 2024

The Kauai Beacon began regularly transmitting a 75 Hz, maximum length sequence encoded, signal that has been received by hydrophones as far as 4000 km from the source. The received signal, which has travelled across the entire ocean basin, contains integrated environmental information about the full path between the transmitter and the receiver. This allows us to simultaneously understand how the environment effects long-range acoustic propagation, and to use the long-range acoustic propagation to estimate environmental variables such as path-averaged ocean temperature. In this talk, we present continued work to analyze the receptions of the Kauai Beacon using open-access ambient sound data recorded in the North Pacific Ocean. We present long-term trends of acoustic arrival times, the spread of the acoustic energy, and frequency shift of the signal due to mooring motion, or ocean state fluctuation. [Work supported by ONR.]
Mid-frequency acoustic tracking of breaking waves
Authors: Saenger Ryan , Lenain Luc , Kuperman William , Hodgkiss William
Published: July 2024

Large surface wave breaking events in deep water are acoustically detectable by beamforming at 5-6 kHz with a mid-frequency planar array located 130 m below the surface. Due to the array's modest 1 m horizontal aperture, wave breaking events cannot be conveniently tracked by beamforming alone. However, their trajectories can be estimated by splitting the array into left-right and upper-lower sub-array pairs, beamforming each sub-array toward the source, and computing the left-right and upper-lower beam cross-correlations. The cross-correlations can be used to estimate the relative time delay between sub-arrays of noise generated by breaking waves. The time delays map to a source location on the surface that can be tracked over time. Source tracks estimated from the sub-array cross-correlations match the trajectories of breaking waves that are visible in aerial images of the ocean surface above the array. [Work supported by the Office of Naval Research.]
Acoustic observations of individual bubble release events from melting glacier ice in an arctic fjord
Authors: Johnson Hayden A. , Deane Grant B. , Glowacki Oskar , Stokes M. Dale , Chitre Mandar , Vishnu Hari , Weidner Elizabeth
Published: July 2024

Melting below the waterline of marine-terminating glaciers and ice sheets has the potential to remove ice that is holding back land-based ice upstream, and increase the rate of global mean sea level rise. It is difficult to observe this melting directly, and the physical processes involved remain an active area of study. As glacier ice melts, the air bubbles trapped in the ice are released into the water. The air bubbles are often at greater pressure than the surrounding hydrostatic pressure in the water, causing them to be released explosively and generate sound through resulting monopole oscillations. Studying this sound at the level of individual bubbles provides an opportunity to learn more about the role of the bubbles in affecting heat flux across the ice-water boundary layer. It is also essential for proposed efforts to use acoustic emissions as a tool to quantify glacier-scale submarine melting. We will present and discuss observations made at the ice-water interface of floating pieces of glacier ice in an Arctic fjord. These observations included measurements of the water thermal structure, velocity, and salinity, as well as ablation of the ice face, made concurrently with acoustic measurements of bubble release pulses from a 2-element hydrophone array.
Differentiable beamforming for adaptive ultrasound imaging
Authors: Hyun Dongwoon
Published: July 2024

Differentiable beamforming (DB) is a powerful new approach to image reconstruction that optimizes the beamforming algorithm to the given imaging target via autodifferentiation. In DB, the beamformer is expressed as a function of some unknown parameters, e.g., the sound speed throughout the medium, the shape of a flexible transducer, or the position and orientation of a swept transducer. Gradient descent is then used to find the parameters that optimize the focusing quality of the beamformer. With the appropriate choice of focusing criterion, the optimal beamforming parameters coincide with the ground truth. We demonstrate DB in applications of ultrasound autofocusing and sound speed imaging, flexible array shape estimation for wearable applications, and sensorless freehand swept synthetic aperture imaging.
Optimization of propellers under consideration of aeroacoustic and aerodynamic goals and installation effects
Authors: Schmähl Michael , Hornung Mirko
Published: July 2024

Advanced Air Mobility (AAM) vehicles like air taxis and cargo unmanned aerial vehicles (UAVs) operate close to urban areas. Therefore, it is necessary to keep the noise footprint of such aerial vehicles at a minimum to gain societal acceptance for AAM vehicle operations. Cargo UAVs are typically highly integrated in terms of functions leading to a high extent of aerodynamic interactions between propellers and the airframe. As a result of these installation effects, unsteady loading noise can become the dominant part of the aerial vehicle noise emissions which leads to a situation, where classical propeller noise reduction measures like blade tip Mach number reduction do not necessarily lead to a reduction in the overall noise emissions. Overcoming these uncertainties in propeller design necessitates propeller noise optimization on an aircraft configuration level. In this work, an existing propeller optimization framework for isolated propellers was extended accordingly: Consideration of propeller inflow velocity perturbations due to installation in the blade element momentum theory-based propeller performance prediction and utilization of a blade element method code (BEM) to consider the scattering of propeller noise on the airframe accounts for configuration noise aspects. Optimization results of a pusher propeller UAV configuration conclude this work.