bluuebunny/crossref_metadata_2025 huggingface dataset:
How do children combine visual speech with other auditory grouping cues?
Authors: Halverson Destinee , Lalonde Kaylah
Published: November 2021

Adults use visual speech to help perceptually group talkers into separate objects and to attend to the target talker. As a result, they benefit more from visual speech in the presence of a two-talker speech masker than in speech-spectrum noise and benefit less from visual speech when other cues are available to support auditory grouping. Recent studies demonstrated that children’s visual speech benefit was similar for a noise masker and a two-talker speech masker, suggesting that children may not use visual speech as a grouping cue. The current study further examined whether children use visual speech as a grouping cue by testing whether 40 seven- to nine-year-old children’s visual speech benefit decreased in the presence of other cues known to promote auditory grouping in children, namely carrier phrases and perceived spatial separation. Children completed an adaptive closed-set speech recognition task in a two-talker speech masker, in auditory-only and audiovisual conditions, and in the presence or absence of one of the auditory grouping cues. Preliminary analyses suggest that children’s visual speech benefit did not decrease when other auditory grouping cues were present. These results provide converging evidence that children in this age range may not use visual speech as a grouping cue.
Variational Bayesian inference for beamforming
Authors: Park Yongsung , Meyer Florian , Gerstoft Peter
Published: November 2021

A variational Bayesian method for beamforming is presented. The proposed method aims at estimating the time-varying directions of arrivals (DOAs) of source signals. Sequential estimation is performed based on a random process representation of the unknown DOAs. Since calculating the posterior probability density functions (pdfs) of the individual DOA variables is intractable, we utilize variational Bayesian inference to analytically approximate these posterior pdfs. A von Mises representation enables closed-form integration over approximate DOA pdfs. The proposed algorithm iteratively estimates DOAs, source amplitudes, number of sources, and model parameters. Furthermore, it is grid-less, promotes sparse solutions, and provides an uncertainty characterization for estimated DOAs. For an improved time-varying DOA tracking performance, inference results from previous time steps can be used as prior information for sequential processing. We evaluate the proposed method using simulated data and acoustic data from an underwater source localization experiment.
On underwater acoustic particle velocity channels: Some experimental results
Authors: Zhang Erjian , Abdi Ali
Published: November 2021

Studies have shown that acoustic particle velocity channels, in addition to the acoustic pressure channel, can be beneficial for underwater acoustic communication [A. Abdi and H. Guo, “A new compact multichannel receiver for underwater wireless communication networks,” IEEE Trans. Wireless Commun. 8, 3326–3329 (2009); A. Abdi, et al., “An overview of underwater acoustic communication via particle velocity channels: Channel modeling and transceiver design,” Proc. Meetings Acoust. 9, 070002 (2010)]. In this paper, we use experimentally measured acoustic particle velocity and acoustic pressure channels, using transmitted linearly frequency modulated (LFM) signals, to investigate and compare various signal and noise characteristics of these channels. Examples include signal and noise powers and ratios, delay spreads of the channels, temporal and spatial auto and cross covariance functions for the particle velocity and acoustic pressure noise components, and frequency responses of the acoustic particle velocity and acoustic pressure channels. Understanding these signal and noise characteristics allows a system designer to design and implement reliable and efficient underwater acoustic communication systems that employ multiple acoustic particle velocity channels, together with the acoustic pressure channel. [The work is supported in part by the National Science Foundation (NSF), Grant IIP-1500123.]
Tidal pressure as a mechanism to explain the steep rise in ambient infrasound below 0.1 Hz at Eleuthera reported by Nichols in 1981
Authors: McBeth Michael S. , Korde Umesh A.
Published: November 2021

R. H. Nichols reported measurements of ambient ocean noise made off Eleuthera Island [J. Acoust. Soc. Am. 69, 974–981 (1981)]. Nichols was unable to identify a mechanism to explain the steep rise of 20 dB per octave from 0.02–0.1 Hz in spectrum levels obtained with hydrophones at depths of 300 and 1,200 m. Here we show that a tidal pressure signal modeled as a ramp pulse waveform through an octave bandpass filter results in spectrum levels increasing about 12 dB per octave with decreasing frequency below 0.1 Hz. If the infrasound noise levels continue to follow the 6 dB per octave increase with decreasing frequency down to 0.02 Hz as they do from 0.1–1Hz, the tidal pressure signal will dominate the infrasound. After a crossover point the infrasound noise signal becomes dominant with increasing frequency. This proposed tidal pressure mechanism could be tested by correlation of observed spectrum levels with the tides just as measurements of surface wind speeds have been shown to correlate with increased infrasound spectrum levels.
The soundscape of restaurants part 4 analysis and practical design directions
Authors: Siebein Keely M. , Siebein Gary W. , Paek Hyun , Roa Marylin , Miller Jennifer , Vetterick Matthew
Published: November 2021

This paper addresses important sonic issues in restaurants and how they can be addressed from an architectural acoustic perspective. Restaurants have complex sound fields composed of many sound sources, listeners and paths. Some of these sound paths are useful, and others are not. Sound paths from one person speaking to another across a table are typically useful (Near), as diners want to hear each other and converse with those at their table and the waiter. Direct and reflected sound paths that travel from a person speaking to non-intended listeners across the room (Far) are not useful. Speech Transmission Indices were measured for “near” and “far” listeners in restaurants. This idea is illustrated with recent case studies. They are also examined with the C50 metric. It is desirable to have higher near STI and lower far STI, when the background and residual noise levels in the space are considered. This study presents the results along with practical design recommendations on how to improve the STI of near sound paths and reduce the STI of far sound paths, such as spatial separation, part height dividers, strategically placed absorbent material, groupings of tables, subdivision of room, and background music among other strategies.
Classification of simulated two-highlight echoes based on time separation in the bottlenose dolphin (Tursiops truncatus)
Authors: Accomando Alyssa W. , Mulsow Jason , Houser Dorian , Finneran James J.
Published: November 2021

Previous studies have suggested that dolphins perceive echo spectral features on both large (macrospectrum) and small (microspectrum) scales. The current study was based on a finding that these percepts are—to some degree—dependent on the dolphin’s ∼250-μs “critical interval” of echolocation. Two dolphins were trained to provide a behavioral response upon detecting a passively presented, simulated two-highlight echo. This “target” had consistent spectral features according to a 120-μs inter-highlight interval (IHI). The target was presented among distractor echoes with various macrospectra and IHIs from 50 to 500 μs (i.e., various microspectra). Following acquisition of this discrimination task, probe stimuli with the macrostructure of the target but IHIs from 50 to 500 μs were presented. Both dolphins responded more frequently to probes with IHIs of 80 to 200 μs during initial presentations. Response strategies diverged, however, with increasing probe presentations: one dolphin progressively responded to a narrower range of probe IHIs, while the second increased response rates for probes with IHIs >250 μs. These results support previous conclusions that perception of macrostructure for complex echoes is non-constant as echo IHI decreases below approximately 80 μs, but results near 250 μs (i.e., the critical interval upper limit) were more ambiguous. [Work funded by ONR.]
Ocular biomechanics and glaucoma
Authors: Sit Arthur J. , Kazemi Arash , Zhang Xiaoming
Published: November 2021

Glaucoma is the leading cause of irreversible blindness worldwide. Ocular biomechanical properties have been implicated in glaucoma pathogenesis, but existing commercial devices cannot determine changes in specific tissues. We recently performed a study to compare corneal wave speed (a measure of corneal elasticity) and ocular rigidity (a whole eye measurement of ocular biomechanics) between glaucomatous and normal eyes. Twenty glaucomatous eyes from 10 patients and 20 normal eyes from 13 controls, matched for age, intraocular pressure (IOP), and axial length were included. Ocular rigidity was calculated based on the difference in supine IOP by pneumatonometry with and without a 10-g weight. Corneal wave speed was determined by ultrasound surface wave elastography in which a small, 0.1 s harmonic vibration at 100 Hz was generated through the closed eyelids. Wave propagation was captured by an ultrasound transducer, and wave speed was determined from the phase change with distance. No significant differences in corneal wave speed between glaucomatous and normal eyes were detected (P = 0.17). However, ocular rigidity was significantly lower in glaucomatous eyes (0.0218 ± 0.0033 vs 0.0252 ± 0.0050 μl−1, P = 0.01). While lower ocular rigidity is consistent with altered biomechanics in glaucoma, the lack of a difference in corneal wave speed suggests that corneal tissue may not be significantly affected, and scleral changes likely play a more important role.
High performance computing and inverse problems in acoustics and structural acoustics
Authors: Bunting Gregory , Miller Scott , Dohrmann Clark , Walsh Timothy
Published: November 2021

Engineering applications in acoustics and structural acoustics commonly require finite element models with large numbers of degrees of freedom. Examples include applications with infinite and semi-infinite domains, as well as problems at high frequency (e.g., ultrasound) where the number of wavelengths in the domain becomes large. The finite element solution of such problems, and their inclusion inside an optimization loop for inverse problems, inevitably involves large numbers of degrees of freedom and systems of equations. Modern high-performance computing is enabling numerical solutions of acoustics applications that were previously intractable. In this talk, we will present an overview of massively parallel acoustic and structural acoustic solution capabilities in Sandia’s Sierra-SD (Structural-Dynamics) software. Sierra-SD is a massively parallel finite element application for structural dynamics and acoustics, having recently demonstrated the implicit solution of models with over 2 × 109 degrees of freedom and running on up to one hundred thousand distributed memory cores. Domain decomposition and MPI parallelism are used to split a large domain into many small domains that can be solved in parallel. Large-scale applications in ship shock loading and vibration of reentry bodies will be shown as demonstrations. [SNL is managed and operated by NTESS under DOE NNSA Contract DE-NA0003525.]
One engineer’s approach to audio system design
Authors: Rasp Olen
Published: November 2021

Designing and implementing a complete audio system presents a unique set of challenges and relies upon a broad range of disciplines: covering acoustical, mechanical and electrical systems. This session will cover one approach to designing small, mass-produced, self-contained audio systems by describing key steps and explaining why they’re important. Topics to be covered include: simulation, measurement and tuning.
Circular microphone array beamforming to improve speech recognition for virtual agents
Authors: Elko Gary W. , Meyer Jens , Teutsch Heinz , Gaensler Tomas
Published: November 2021

Under funding from an NIH NIDCD SBIR phase 1 and phase 2 grant, mh acoustics built a 16-element concentric circular microphone array using both analog and digital MEMS microphones. The circular microphone array design was trademarked as the EigenEar® microphone array and the unique beamforming processing is covered by U.S. patent 8903106. The presentation aims at showing that a circular third-order differential beamformer is capable of improving the recognition rate of popular voice recognition services used by a number of commercially available virtual assistants. These services offer an API to a client allowing speech data to be uploaded, analyzed, and returned in text form to the client. Experiments were done to compare the recognition accuracy from two separate audio streams. The EigenEar microphone array has two output channels and one channel contained the output of one omnidirectional microphone in the array and the other channel contained the output of the beamformer. The two audio streams are time synchronous so both streams presented to the virtual assistant are time aligned. The talk will describe the EigenEar circular microphone array and how the experiment was setup and the ASR results obtained from the virtual agents.
Transient oscillations in steelpan drums tracked via machine learning
Authors: Hawley Scott H. , Morrison Andrew C.
Published: November 2021

Applying a machine learning based object detector to high-speed videos of Caribbean steelpan drums illuminated by laser electronic speckle pattern interferometry (ESPI), we can track the development of sympathetic vibrations in response to drum strikes. This object detector was trained on a dataset of crowdsourced human-annotated images obtained in the Steelpan Vibrations Project on the Zooniverse platform. When the model is used to supply annotations to thousands of unlabeled video frames, we measure visual oscillations at frequencies consistent with audio recordings of these drum strikes. In this talk we share early physics results such as the unanticipated phenomenon of sympathetic oscillations of higher-octave notes that significantly precede the rise in sound intensity of the corresponding second harmonic tones; the mechanism responsible for this remains unidentified.
An external calibrator system for the hyperion sensors
Authors: Talmadge Carrick
Published: November 2021

The NCPA has developed an external calibrator system which is nearing maturity. This calibrator is attached as a replacement sensor lid for the Hyperion sensor, and injects the signal into the back volume of the Hyperion sensor. When the external calibrator is mated to the sensor, the integrated sensor-external calibrator package behaves as a self-calibrating sensor. The external calibrator allows the Hyperion to operate nominally and without significant change in response with the external calibrator installed. The calibrator is driven by an external signal generated by the digitizer (e.g., the CAL signal on a GEOTECH). This system is capable of producing signals with amplitudes greater than 20-Pa in the operational environment between 0.01 and 10 Hz. We report here on the performance metrics (frequency flatness, level linearity, etc.) as well as summarize the theory of operation of the device.
A Midsummer Flights’ Dream: Balloon-borne infrasound-based aerial seismology
Authors: Martire Léo , Krishnamoorthy Siddharth , Komjathy Attila , Bowman Daniel , Pauken Michael , Jacob Jamey , Elbing Brian R. , Hough Emalee , Yap Zach , Lammes Molly , Linzy Hannah , Morrison Zachary , Swaim Taylor , Vance Alexis , Simmons Payton , Cutts James
Published: November 2021

Aerial seismology (AS) consists in detecting and characterizing atmospheric infrasound induced by ground displacements. Several studies have demonstrated that seismo-acoustic infrasound is highly similar to the seismic ground motion, making it a viable alternative for seismology on planetary bodies where deploying seismometers is technologically challenging. Until recently, such experiments were restricted to artificially-generated seismic events. However, on July 22, 2019, Brissaud et al. detected for the first time the infrasonic signature of a magnitude 4.2 earthquake from a high-altitude solar-heated balloon. In order to further demonstrate the feasibility of AS, additional detections are needed. Using similar balloons and payloads, stratospheric flights were launched several times per week during the summer of 2021 over Oklahoma’s seismogenic zone. In this work, we present this campaign and its initial results. We describe the flight system, instrumentation, and details of the campaign design. We focus on the possible detections of earthquakes during the campaign using numerical simulations. For selected events, we present the balloon pressure data and extract potential arrivals. We perform full-waveform simulations using SPECFEM2D-DG to confirm those arrivals. We conclude with statistical arguments for earthquake detections and recommendations for future flights. Earthquakes are numerous in Oklahoma, but are of low and decreasing magnitudes. Nonetheless, this campaign’s dataset is unique for the development of AS.
Top-down and bottom-up expectations in the prefrontal and auditory cortices
Authors: Suriya-Arunroj Lalitta , Gold Joshua I. , Cohen Yale E.
Published: November 2021

Auditory perceptual decision-making is modulated by interactions between bottom-up (sensory-driven) and top-down (expectation-driven) processes. Despite the importance of these interactions, little is known about their underlying neural mechanisms. We investigated these mechanisms by recording neural activity in the auditory and prefrontal cortices of rhesus monkeys while they performed a challenging auditory decision-making task. The monkeys decided whether the last (“test tone”) in a sequence of tone bursts, embedded in broadband noise, was low or high frequency. Task difficulty was titrated by varying the sound level of the test tone relative to the noisy background. Bottom-up expectations were manipulated by presenting three identical low- or high-frequency tone bursts (“pre-tones”), establishing sequence regularity. Top-down processing was manipulated by presenting a visual cue that indicated the prior probability that the subsequent test-tone would be high or low frequency (“pre-cue”). The monkeys’ behavioral choices and response times were biased by both the pre-tones and the pre-cues, with stronger and more consistent effects by the pre-cues. Neural activity was modulated preferentially by the pre-tones in auditory cortex and by the pre-cues in prefrontal cortex. These findings imply functional segregation between bottom-up and top-down processing in the primate brain during auditory perceptual decision-making.
Transformation of acoustic information to sensory decisions in parietal cortex
Authors: Yao Justin , Sanes Dan
Published: November 2021

Integrating sensory information over time is fundamental for guiding perceptual decisions. This process is facilitated by the transformation of stimulus representations downstream of sensory cortex. Here, we ask how the neural representations of auditory information are transformed in the auditory-recipient parietal cortex, a region that is causally associated with sound-driven perceptual decisions. Wireless recordings of neural activity were conducted in parietal cortex while gerbils performed an alternative forced-choice (AFC) auditory temporal integration task. Gerbils were required to discriminate amplitude modulated (AM) noise at 4 vs 10 Hz across various signal durations (100–2000 ms). Task performance was poor at short AM durations (100–300 ms), improved with longer durations, and reached an optimum at ≥600 ms. During task performance, individual neurons displayed a rise in firing rate that peaked prior to the animals’ decision. Population activity from simultaneously recorded parietal cortex neurons was strongly correlated with behavior outcomes, leaving open whether parietal representation was purely motor-related or included a sensory component. Thus, we evaluated population activity during disengaged sessions, and found a representation of the acoustic stimulus. Our findings suggest that parietal cortex neurons represent both the acoustic stimulus and sound-driven decision, demonstrating the progression of auditory processing downstream of auditory cortex.
Resonator measurements and modeling of the low-frequency sound speed of seagrass leaves
Authors: Torres Nicholas A. , Wilson Nathan G. , Ballard Megan S. , Lee Kevin M. , Venegas Gabriel R. , Wilson Preston S.
Published: November 2021

Previous investigations of seagrass have revealed acoustic phenomena that depend on the material properties of the plant tissue and gas contained within the lacuna of the leaves. However, the application of predictive models to describe these observations has been limited to effective medium models that neglect both the effects of elastic properties of seagrass tissue as well as its structure. To address this, we developed a physiological model of a seagrass leaf that includes the epidermis, a continuous layer on the surface of the leaf that provides rigidity, and the aerenchyma, a soft plant tissue containing the lacuna. To validate the seagrass leaf model, acoustic resonator experiments were performed to measure the low-frequency sound speed of seagrass leaves, and the physical dimensions of the epidermis and aerenchyma were assessed through the examination of microscopic images of leaf cross sections. Using this imagery, a finite element model of the seagrass leaves was created, and COMSOL was used to simulate the resonator experiment. The comparison of the measured and modeled acoustic data provides insights into the parameters of the seagrass tissue that affect the acoustic response, specifically the shear moduli of the epidermis and aerenchyma. [Work supported by ARL IR&D and ONR.]
Attenuation of external vibrations transmitted into platforms by granular media for special applications
Authors: Tavossi Hasson M.
Published: November 2021

Mitigation of mechanical vibrations from external sources into structures by granular media is investigated to prevent transmission into the structure by surrounding granular media layers. Mechanical properties of granular media can be selected for absorption of specific frequency band of external vibrations. The absorption frequency band of the granular media can be move by design to required frequency band where scattering and dissipation of vibrational energy is maximized. Samples of granular media layers are subjected to external vibrations of different intensity and frequency. Experimental values are presented for attenuation versus frequency for different layers of selected grain sizes, at audible frequencies. The goal is to determine media properties that maximize vibration attenuation for special applications of vibration free platform for such specialized application as supports for atomic force microscopy supports and more recent gravitational-wave detectors.
Effects of phonotactic legality on gestural coordination in consonant clusters: An electromagnetic articulography study
Authors: Cheng Hung-Shao , Masapollo Matthew , Hagedorn Christina , Buchwald Adam
Published: November 2021

Cross-language studies of speech production have shown that English speakers can produce phonotactically illegal onset fricative-nasal clusters (e.g., /fn/) with high accuracy based on acoustic analyses. However, it remains unclear whether the articulatory gestures affiliated with the fricative-nasal segments are produced with comparable gestural timing to native onset clusters (e.g., /sm/, /fl/). We here used electromagnetic articulography (EMA) to investigate whether the production of non-native /fn/ onset clusters exhibits a comparable amount of consonant-vowel gestural overlap to native onset clusters (i.e., /sm/ and /fl/) in nonwords. Previous articulatory investigations have demonstrated that native English onset clusters exhibit an increase in gestural overlap between the vowel-adjacent consonant and the vowel (e.g., SMAGDEEP) when compared to the corresponding singleton (MAGDEEP). We controlled for the vocal tract configuration (e.g., jaw position) by comparing each onset cluster to heterosyllabic sequences consisting of the same consonant sequences (e.g., /sm/ vs /s#m/). While the data collection is still ongoing, the preliminary results (n = 3) suggest that when the complexity of the onset increased, vowel-adjacent consonantal gestures showed greater temporal overlap with vocalic gestures for phonotactically legal sequences (SMAGDEEP versus MAGDEEP) but not illegal sequences (FNAGDEEP versus NAGDEEP).
Gestural timing and stability in hausa implosives
Authors: Oh Miran , Goldstein Louis , Byrd Dani
Published: November 2021

Articulatory dynamics of glottalic consonants—ejectives and implosives—show strictly different intergestural timing patterns that those of pulmonic consonants. For example, oral constriction and vertical larynx gestures in Hausa have been shown to be sequentially produced for glottalic consonants and simultaneously produced for their pulmonic counterparts (Oh et al., ASA 2018, PaPE 2019). In the present work, we predict that glottalic consonants will exhibit tighter, more stable intergestural coordination than pulmonic consonants, due to the superordinate aerodynamic goal in glottalics—namely, that to generate a rapid oral air pressure change the vertical larynx action must begin during the oral closure interval. The current study examines data from three Hausa speakers producing voiced implosives and voiced plosives, using real-time MRI to obtain kinematic information on the oral constriction and the vertical larynx action. A region-of-interest analysis quantifies oral constrictions and a centroid analysis tracks vertical larynx actions. Findings confirm that intergestural timing patterns are contrastive between implosives and voiced stops. Moreover, results on relative timing stability, indexed by token-to-token variability and covariance relations between timing lags and gestural durations, indicate that the intergestural timing for implosives is more stable than for voiced stops. [Work supported by NIH and NSF.]
Muscle strain analysis from diffusion tractography and dynamic magnetic resonance imaging of the moving tongue
Authors: Xing Fangxu , Liu Xiaofeng , Reese Tim , Stone Maureen , Wedeen Van , Prince Jerry L. , El Fakhri Georges , Woo Jonghye
Published: November 2021

Strain estimation of a deforming human tongue is an important task in motor control studies. Various magnetic resonance imaging (MRI) modalities provided versatile acquisition tools, facilitating accurate strain computation and quantitative analysis. We report a method that combines data from diffusion and dynamic MRI to yield strain values along internal tongue muscle fiber directions. Dynamic MRI provides spatiotemporal muscle motion. Diffusion tractography provides muscle fiber geometry. Since the two datasets exist in different physical spaces and tractography is susceptible to numerical errors if spatially transformed, we transformed only muscle motion fields from the dynamic MRI space to the diffusion MRI space using diffeomorphic registration. Strain tensors were then computed and projected onto the fiber directions. Masks were used to extract strain of individual muscles. Three tongue motions while pronouncing two utterances and making a forward protrusion were processed. Resulting strain patterns on seven internal muscles showed that some muscles stayed stretched or compressed over all motion time while other muscles switched between stretches and compressions depending on specific tongue shapes. The proposed method enables accurate assessment of variations in muscle strains, which potentially reveals muscle activation patterns and provides insights into the tongue's detailed mechanics in speech motor control.
Prediction of vocal roughness using measures of temporal envelope fluctuation obtained from an auditory model
Authors: Park Yeonggwang , Ozmeral Erol J. , Anand Supraja , Shrivastav Rahul , Eddins David A.
Published: November 2021

Vocal roughness often is present in many voice disorders, but the assessment of roughness mainly depends on the subjective auditory-perceptual evaluation and lacks unique acoustic correlates. This study aimed to apply the concept of roughness in general sound quality perception to vocal roughness assessment and to characterize the relationship between vocal roughness and temporal envelope fluctuation measures obtained from a biologically inspired auditory processing model. Ten /ɑ/ recordings with a wide range of roughness were selected from an existing database. Ten listeners evaluated perceived roughness using a single-variable matching task. Temporal envelope fluctuations of the recordings were analyzed with an auditory processing model of amplitude modulation based on a modulation filterbank tuned to different modulation frequencies. Pitch strength and the smoothed cepstral peak prominence (CPPS) also were computed for comparison. Individual simple regression models yielded envelope standard deviation from a modulation filter with a low center frequency (64.3 Hz) as a statistically significant predictor of vocal roughness with a strong coefficient of determination (R2 = 0.81). Pitch strength and CPPS were not significant predictors of roughness. These results support the utility of envelope fluctuation measures from an auditory model as objective correlates of vocal roughness. [Work supported by NIH R01DC009029.]
Seeking the source of vocal fold lesions towards measuring contact pressures during phonation with a pressure-sensing-matrix at hemi-larynx experiments
Authors: Scheible Florian , Veltrup Reinhard , Schaan Casey , Lamprecht Raphael , Semmler Marion , Staggl Manuel , Sutor Alexander
Published: November 2021

During phonation, the vocal folds execute a complex movement. Related to the subglottal pressure and tension of the vocal folds themselves, this movement may differ, furthermore depending on the kind of phonation a collision between both vocal folds may occur. If the vocal folds are overstrained, this can cause lesions. To gain knowledge about the vocal folds movements and the way of their collisions, a high-speed evaluation unit for a pressure-mapping sensor was developed. The sensor brings along a local resolution of 27.6 measure points per square centimeter and with the developed unit an adjustable framerate up to 1 kHz can be realized. Due to a sensor thickness of about 0.2 mm, an integration into hemi-larynx flow experiments is quite simple without vigorous changes on the setup. Because of an unrestricted field of view it is possible to record the movements with a high-speed camera. These recordings will be correlated with contact pressures in the post processing. During these experiments, different flowrates of the excitation air and various abduction and elongation steps on the hemi-larynx are obtained to study the effect of those manipulations.
Acoustic and aerodynamic aspects of nasality in Guarani
Authors: Demasi Rita , Demolin Didier
Published: November 2021

Guarani presents some interesting characteristics for nasality: nasalization of voiceless and voiced fricatives and long nasal spans in which two types of nasals (strong and weak) are observed. This study is based on recordings made with 4 native Guarani speakers from Paraguay (1 woman and 3 men) using synchronized acoustic and aerodynamic (oral and nasal airflow) recordings. Data show that voiced fricatives lose their frication when nasalized ṽ > ʋ̃ [1]. For voiceless fricatives some nasal airflow can be observed, but no acoustic effects are observed below a certain threshold. Above this threshold, the acoustic spectrum is damped and the frication noise intensity is reduced, creating acoustically predictable phonetic variants s̃  > θ; x̃  > h. Thus, perceptually oral segments can be produced with a velopharyngeal port opening during voiceless fricatives, letting weak nasal airflow passing through (0.1–0.2 dm3/s). Two types of nasals are observed in nasal spans: strong and weak [2]. Strong nasals occurring after voiceless obstruents have a sharp nasal airflow peak, up to 2 dm3/s, after the oral constriction. This shows that the velum closure is achieved after the oral closure. Weak nasals occur in the environment of sonorants and vowels with weaker nasal airflow values. [1] J. J. Ohala and M. Ohala (1993). [2] E. Gregores and J. A. Suarez (1967).
Reflection matrix approach in a multiple scattering regime: Application to the tracking of a sinking sphere in quicksand
Authors: Le Ber Arthur , Bureau Flavien , Jia Xiaoping , Tourin Arnaud , Fink Mathias , Aubry Alexandre
Published: November 2021

Conventional ultrasound imaging generally relies on a single scattering assumption. Assuming a homogeneous speed of sound, a one-to-one correspondence is actually found between each scatterer position and the time-of-flight of the associated echoes. However, in strongly scattering media such as granular media, multiple scattering (MS) cannot be neglected beyond a few scattering mean free paths ls, the typical distance between two scattering events. A conventional image is then no longer a satisfying estimator of the medium reflectivity. Here, we propose an original solution relying on a matrix formalism to cope with MS and image deeper than the conventional MS limit. As a proof-of-concept, our experiment consists in the acquisition of a reflection matrix associated with a 2D ultrasound probe (1024 elements −3 MHz central frequency) of a steel sphere sinking in fluidized glass beads immersed in water (ls ≈ Ø600 μm). As expected, we show that the target echo vanishes into the MS background when it goes deeper than a few ls. Interestingly, an iterative time-reversal analysis of the reflection matrix is proposed to compensate for the phase distortions induced by the gap between the effective medium properties and our beamforming model. The target can then be tracked at larger penetration depths than the usual MS limit.
Underwater acoustic intensity characterization of anechoic panels in laboratory tank
Authors: Dobbs Corey E. , Fronk Gabriel H. , Neilsen Tracianne B. , Vongsawad Cameron T.
Published: November 2021

Acoustic vector intensity contains more information about sound propagation than standard pressure measurements. This fact motivates the characterization of sound propagation in an acrylic rectangular water tank with dimensions of 3.6 × 1.2 m2 and a maximum depth of 0.91 m, contained in the Underwater Acoustics Lab at Brigham Young University. With the acquisition of an M20-040 Particle Motion Sensor from GeoSpectrum Technologies Inc, comparisons are made between the p-p and the p-u methods of calculating intensity as a function of frequency and source-receiver range. In addition, the decrease in intensity is quantified when Apltile SF5048 anechoic panels made by Precision Acoustics are used to line the side of the tank. This work helps characterize the impact of panels on sound propagation in the tank. The continuation of research on acoustic vector intensity will also allow for future research collaboration with biologists at BYU to make important measurements relating to the effects of sound intensity on the auditory responses of fish.
Observation of variable-order Lévy statistics in atomizing microscale capillary wave dynamics
Authors: Orosco Jeremy , Friend James
Published: November 2021

When excited with very small amplitude [O(≤10−9) m], very high ultrasonic frequency [O(≥106) Hz] vibrations, an otherwise quiescent small volume [O(10−6) μl] of water will exhibit oscillations at its ambient interface that are visible by eye [O(10−2) m and O(101) Hz]. Recent experimentation has shown that this remarkable behavior occurs in the absence of any classically predicted originating mechanisms such as Faraday instabilities, so that the physics of ultrasonically vibrated microscale water volumes remains enigmatic, lacking detailed theoretical characterization. In this talk, we present recently acquired, high-speed holographic time-dependent measurements of the ambient interface of a microscale water volume subject to acoustic forcing in the MHz regime. We show that the statistical distribution of surface oscillations—capillary waves—is a continuously variable function of the input amplitude, varying from near Gaussian at small powers to Lévy α-stable at higher powers. The relationship between this statistical observation and near-atomization physics is discussed and potential modalities for low-dimensional mathematical characterization of the system are presented.
Using neural networks to estimate the probability density function of transmission loss in ocean environments with a database-driven model of uncertainty
Authors: Lee Brandon M. , Johnson Jay R. , Dowling David R.
Published: November 2021

The prediction of transmission loss (TL) in the ocean depends on the relevant environmental characteristics, such as sound speed field, bathymetry, and bottom properties. These characteristics are often uncertain as they are commonly not all measured in situ, and are instead estimated from available databases. Thus, the resulting predictions of TL are uncertain, and this uncertainty can be quantified via the probability density function (PDF) of TL. Given a model for the environmental uncertainty, Monte Carlo techniques and thousands of realizations of the environment can be used to estimate the PDF of TL, but this method is computationally costly. A variety of alternative uncertainty-estimation techniques have been proposed, including a machine learning approach which uses neural networks trained on large Monte Carlo-produced TL datasets. The resulting neural network inherits the limitations of its training datasets and their underlying model of environmental uncertainty. A new environmental uncertainty model is described here which uses higher-resolution databases. A revised neural network approach to predicting PDFs of TL is developed and tested on ∼4.5 × 106 examples across 300 environments with the new, more realistic model of uncertainty at ranges up to 100 km for source frequencies between 50 and 600 Hz. [Sponsored by an NDSEG Fellowship.]
Force chains, creep and acoustic reflection in marine sediments
Authors: Chotiros Nicholas P.
Published: November 2021

Marine sediments are water-saturated granular media. A feature of granular media is that the stress is not uniformly distributed but concentrated in force chains. Several force chains acting in parallel transmit external stresses through the medium. A force chain is a chain of particles through which the external stresses are concentrated and transmitted. Given that the contact stiffness between particles may be approximated as a Maxwell element, i.e. a spring in series with a damper, then the stiffness of any force chain may be modeled as several Maxwell elements in series. It is known that any number of springs and dampers in series may be reduced to just one spring and one damper in series, i.e., one equivalent Maxwell element. Therefore, several force chains in parallel may be modeled as parallel Maxwell elements. However, parallel Maxwell elements may not be reduced to one Maxwell element. The stiffness of a distribution of parallel Maxwell elements falls under the generalized creep model. This model is used to represent the skeletal frame of a larger porous medium model. The inversion of model parameters from the reflection coefficient is explored in the context of a muddy sediment. [Work supported by ONR, Ocean Acoustics Program.]
Deep-learning exploration of the acoustic granularity of bat habitats
Authors: Zhang Liujun , Farabow Andrew , Singhal Pradyumann , Müller Rolf
Published: November 2021

Many bat species are able to find their way through densely vegetated habitats and select their microhabitats to suit their respective needs. This raises the question as to how granular the natural habitats of bats are when sensed through the echoes triggered by the animals' biosonar pulses. To investigate this question, a portable biomimetic sonar head has been used to collect about 40 000 foliage echoes across a natural forest site on the Virginia Tech campus that was approximately 250 × 140 m2 in size. Each recorded echo was assigned a spatial location that was estimated from the outputs of a concurrently operated GPS receiver. These spatial locations were then used to cluster the echoes into a varying number of compact patches using a k-means clustering algorithm. To determine whether these spatial patches could be determined from the echoes, a convolutional neural network based on the ResNet50 architecture was trained to classify the echoes with respect to their spatial labels. Even based on just a single echo, up to 100 different spatial patches could be distinguished in this way with accuracies greater than 95%. These results demonstrate that bat biosonar can capture sensory information for small-scale navigation in natural forest habitats.
Investigating the acoustic directionality of mouse ultrasonic vocalizations
Authors: Ma Yichong , Warren Megan R. , Neunuebel Joshua P.
Published: November 2021

Across the animal kingdom, ultrasonic vocalizations (USVs) are used as a means of communication, navigation, and predation, and in some species (e.g., echolocating bats and whales), the directionality of the signal facilitates these processes. The utility and characteristics of mouse USVs, however, are less clear. Using an 8-channel microphone array, we recorded, localized, and assigned USVs to individual mice that were in isolation (n = 28) or socially interacting (male-female dyads, n = 13; 4-mouse, mixed-sex groups, n = 11). Males emitted a total of 3675 (100%), 22 268 (84.48%), and 73 488 (82.05%) of the assigned vocalizations when in isolation, interacting with a female, or socializing in a group. By examining the relationship between the USV sound intensity on the eight microphones and the head directions of the mice, we observed that male mice consistently produced directional USVs across each of the three behavioral contexts. Specifically, USV intensity was strongest in the direction that the mouse was facing and weakest in the opposite direction. Overall, these findings directly demonstrate that male mouse USVs are directional and may provide insight into the communicative function of mouse vocalizations.
High-frequency quantitative ultrasound to assess chemical crosslinking induced changes in the posterior sclera
Authors: Hoerig Cameron , McFadden Sally , Hoang Quan V. , Mamou Jonathan
Published: November 2021

Myopia alters the collagen microstructure of the sclera which changes the tissue biomechanical properties. Although most forms of myopia are mild, progression of the disease to high or pathologic myopia can lead to significant weakening of the sclera and greatly increase the risk for the formation of a posterior staphyloma, a sight-threatening condition. Potential treatments to counteract effects of myopia on the sclera include chemical crosslinking (CXL). Formaldehyde releasing agents like sodium hydroxymethylglycinate (SHMG) are an attractive option for the posterior sclera because they increase tissue stiffness and require no light activation. Previous research has demonstrated that high-frequency quantitative ultrasound (QUS) is sensitive to the microstructural changes in the sclera caused by myopia. In this study, we investigate the ability of QUS to monitor microstructural changes caused by CXL. Ex vivo pig eyes were immersed in a 26.5 mM SHMG solution and scanned by an 80MHz ultrasound transducer at regular time intervals. RF echo data were analyzed to compute QUS parameters from the backscatter coefficient, normalized power spectrum, and echo envelope statistics. Correlations between QUS parameters and immersion time were investigated to evaluate the efficacy of QUS for monitoring CXL treatment. Results of this study demonstrate the capability to high-frequency QUS to assess changes in tissue microstructure caused by CXL with SHMG.
Non-invasive ultrasound stimulation on the retina and visual cortex for visual restoration
Authors: Lu Gengxi , Qian Xuejun , Li Runze , Thomas Biju , Humayun Mark S. , Zhou Qifa
Published: November 2021

Nearly 30% of the U.S. population aged over 75 have age-related macular degeneration and retinitis pigmentosa. 10% of them may become legally blind. Currently, blindness cannot be cured and patients’ living quality can be compromised severely. Electrical visual prostheses are used as the best near-term strategy. However, they have challenges including invasive devices, complex implantation surgeries, and limited resolution. Non-invasive ultrasonic neuromodulation can be a promising technology for non-invasive visual prostheses. Our work showed that direct ultrasound stimulation on the retina can evoke neuron activities in either normal-sighted or retinal degenerated blind rats in vivo, indicating a promising future of ultrasound stimulation as a novel and non-invasive visual prosthesis for translational applications in blind patients. For patients with damaged optic nerves, retinal prostheses are not effective. Thus, we also investigated the feasibility of transcranial focused ultrasound for non-invasive stimulation of the visual cortex to develop a non-invasive cortical visual prosthesis. Besides stimulations, ultrasound has been used to non-invasively monitor brain activity by imaging cortical blood flow. Our study shows that ultrasound-induced visual responses can be monitored by ultrasound flow imaging of the brain, constructing an ultrasound stimulation-recording closed-loop system.
The noise dose range of the X-59 estimated from propagation simulations
Authors: Doebler William , Loubeau Alexandra
Published: November 2021

NASA’s X-59 aircraft will soon be flown in a series of low-boom community noise surveys across the USA. Community test experimental designs will include noise dose schedules, which require an estimate of the noise dose range that X-59 can produce. To determine the dose range, propagation simulations using NASA’s PCBoom code were completed using CFD-generated X-59 C612A near-field pressure data for an on-design condition (Mach 1.4 at 53 200 ft) and two off-design conditions (Mach 1.4 at 46 000 ft and Mach 1.3 at 43 000 ft). Near-field data at four cardinal aircraft headings were propagated through one year of realistic atmospheric profiles from the Climate Forecast System Version 2 database at several USA locations. Statistics of the mean and range of the Perceived Level (PL) of the booms in the inner 40 km of each carpet as well as the carpet width were computed. Results indicate the typical inner carpet mean PL is approximately 70–87dB depending on the aircraft condition. The typical PL range across the inner carpet is 6–8 dB (on-design) and 5–13 dB (off-designs). The carpet widths ranged from 32–55 km. Understanding these quantities for various flight and atmospheric conditions is important for planning X-59 community noise surveys.