bluuebunny/crossref_metadata_2025 huggingface dataset:
Harnessing rotational geometry to design reconfigurable dispersion and refractive index in nonlinear acoustic metamaterials
Authors: Fang Lezheng , Leamy Michael
Published: May 2022

We investigate 1D and 2D monatomic lattice structures composed of in-plane rotators coupled by angled elastic linkages and explore their reconfigurable dispersion, negative refraction, amplitude-dependent dynamics, and acoustoelastic effect. At small amplitude, the linear band structure can be configured to be either acoustic or optical in nature by changing the connecting locations on the rotators, which corresponds to positive and negative refractive index. An interface problem between two rotator lattices with opposite dispersion type is modeled, and illustrates negative refraction in numerical simulations—experimental measurements are in progress. Its frequency–transmission relation matches the linear theory. At higher amplitude, the hardening nonlinearity shifts the dispersion and induces amplitude-dependent transmission. A novel nonlinear phenomenon–amplitude saturation (a constant far-field transmission independent of input amplitude) is observed when the transmitted wave falls in the nonlinear stopband and simultaneously the linear passband of the receiving lattice. We analyze the nonlinear effects via perturbation methods and propose a framework for evanescent-specific nonlinear waves to explain the saturation phenomenon. Additionally, we observe a strong acoustoelastic effect in chiral-patterned rotator lattices, where a static stretch can shift the equilibrium positions of the rotators and morph the band structure from acoustic to optical.
Dispersion in lattices with patterns of hardening and softening stiffness nonlinearity
Authors: Fronk Matthew D. , Konarski Stephanie G. , Sieck Caleb F. , Ikei Alec K. , Guild Matthew D.
Published: May 2022

Recent focus has been given to analytically predicting amplitude-dependent dispersion in periodic structures with weak stiffness nonlinearity. These dispersion relationships may inform devices such as amplitude-dependent filters, waveguides, and diodes. However, attention is generally restricted to either spatially uniform nonlinearity or mutually exclusive distributions of hardening or softening stiffness. This study investigates dispersion in lattices with spatial modulations in stiffness nonlinearity. Special attention is given to modulations consisting of both hardening and softening nonlinear terms. A multiple scales perturbation analysis reveals that patterns of hardening and softening stiffness enable both lifting and lowering of a passband’s frequencies. In such cases, passbands contain discrete frequency and wavenumber pairs that prevent amplitude-dependent dispersion shifting. Numerical integration of the lattice equations of motion are carried out to confirm the analytically predicted dispersion behavior. A design of experiment is proposed in which strength and sign of nonlinearity can be tuned with the initial angle of additively manufactured grounding springs. [Work supported by the Office of Naval Research.]
Inverse design of non-periodic nonlinear metamaterials for nonlinear ultrasonics
Authors: Ghodake Pravinkumar R.
Published: May 2022

Previous work by the author gives an idea about the effective design of linear and phononic “periodic” metamaterial using shape optimization to suppress the system-generated 2nd harmonics of a longitudinal wave during nonlinear ultrasonic testing [Ghodake, J. Acoust. Soc. Am. 150, A149 (2021)]. That work considers only the geometric nonlinearity of the layered materials and sinusoidal waves as an input short pulse. The present work implements a shape optimization technique to obtain the optimal design parameters of the “non-periodic” metamaterial by considering both material and geometric nonlinearities of the layered materials present in the phononic crystal as this assumption is close to the real experimental situations. Gaussian short input pulses are considered in this study with two different objectives such as only reducing the amplitude of the 2nd harmonics and reducing the amplitude of 2nd harmonics, maximizing the amplitude of 1st harmonics as well as maintaining the Gaussian shape of the output pulse which makes this inverse problem challenging. This study demonstrates the applicability of the non-periodic metamaterial in practical situations and the importance of the proposed inverse design approach in linear and nonlinear elastic wave propagation applications such as ultrasonic waves and seismic waves.
Speaker sincerity influences F0-coupled head motion in spontaneous monologues
Authors: Tiede Mark , Chen Wei-Rong , Whalen D. H.
Published: May 2022

Movements of the head during speech serve multiple communicative purposes, including perceptual enhancement of prosodic F0 contours. However, it remains uncertain how much of any correlation between head movement and F0 may be due to physiological coupling mechanisms exerting effects on glottal tension. In this work, six native speakers of American English (3F) were videorecorded during production of spontaneous monologues lasting 90 seconds. Each speaker extemporized twice on two topics chosen from a list (e.g., "video games waste time"). One of these they agreed with ("sincere"), and the other they pretended to agree with ("insincere"). Speaker head movements were quantified as displacement/rotation of a six DOF rigid body from the videos using OpenFace (Baltrušaitis, 2018). F0 for each speaker was converted to semitones relative to the median value for that speaker. Results show larger semitone excursion range but smaller head movement range for the sincere condition, with no significant differences in syllable rate across conditions. LME models predicting absolute semitone changes from head displacement show significant positive slopes for main effects of movement and sincerity, and an additive interaction for sincere productions. These differences suggest that, while head movement correlates with F0 overall, speaker sincerity can interact with the relation.
Quantifying multiplex mergers in progress between moving targets
Authors: Freeman Valerie
Published: May 2022

Pillai scores are becoming popular for quantifying degree of overlap, separation, or shift between two vowel distributions in F1 x F2 space (Nycz & Hall-Lew, POMA, 2013). However, some changes in progress involve more than two shifting vowels, multiple target locations, or variable directions of shift, making them difficult to quantify with single measures. An example are back/central pre-lateral mergers in Oklahoma, where /ʌl/ shifts toward /ol/ dull-dole and /ʊl/ shifts toward /ol/ or /ul/ pull-pole or pull-pool. This presentation compares several methods of numerically describing the location of /ʊl/ pull in relation to /ol, ul/, which tend to be separate but do not necessarily back to the same degree. They can serve as targets or “anchors” for the more variable /ʊl/, but without stable locations themselves, some sort of rotation, geometric transformation, or dimensional reduction is necessary. New methods under consideration include proportional locations between anchors, ratios of Pillai scores with each anchor, and areas of triangles between vowels. All will be evaluated for their specific usefulness to the example merger and for their applicability to less complicated shifts, like dull-dole in the same speakers, and differently complex shifts like three-way prevelar merger (bag-beg-bagel) in Pacific Northwest English.
Syllable-wide distribution of acoustic cues to coda voicing
Authors: Arzbecker Lian J. , Jacewicz Ewa , Goebel Riley , Fox Robert A.
Published: May 2022

In English, the strongest acoustic cues to preserving the voicing contrast in coda stops are in the preceding vowel: a voiced coda is associated with a longer vowel and a voiceless coda with a shorter vowel. Our recent work (Jacewicz et al., 2021) examining structured variability in stop voicing implementation in female productions showed that the cues to stop coda voicing extended to the syllable initial stop. In running speech, the /b/-closure in “bad” was shorter when coda was voiced, and it was longer when coda was voiceless (“bat”). Here, we test the hypothesis that voicing contrast cueing the “bad-bat” distinction is reinforced syllable-wide and involves specific long-distance timing relationships between closures of both stops, the extent of their closure voicing, vowel duration, and positive VOT. The current dataset consists of 2610 productions by 45 adult males, who are also diversified by dialect. Preliminary analyses confirmed that segmental voicing information is distributed over long domains (here, a monosyllabic word) and that cues to coda voicing are available in the syllable onset. These findings imply that temporal relationships among acoustic phonetic detail cueing lexical distinctions can potentially enhance the perceptual dimensions of perceived syllable- or word-wide voicelessness and voicing.
The time course of first formant movement in normal and loud speech
Authors: Koenig Laura , Fuchs Susanne
Published: May 2022

Louder speech tends to be slower than typical speech. For some vowels (viz., low and lax ones), louder speech may also be associated with higher first formant frequencies (F1s) at vowel midpoint. Possibly, increased duration allows speakers more time to reach a lower jaw position, thus a higher value of F1, in loud speech. In earlier work, we found that some loudness differences appeared at 25% and 75% of vowel durations, i.e., they were seen for much of the vowel. The current study presents data from 11 German-speaking women producing naturally elicited typical and loud speech. Target words included high, low, tense, and lax vowels with surrounding consonantal place controlled. We will present full vowel trajectories, i.e., from preceding to following consonants, to assess the time course of F1 differences across vowel types and loudness conditions. F1 will also be considered within normalized time intervals to control for durational differences between conditions. We expect that F1 formant trajectories will show minimal loudness differences throughout the vowel for high tense vowels, but time-varying differences will be more apparent for low and lax vowels, and appear rather early in the vowel.
Acoustic effects of syllable position of /s/ in American English: Is there a “dark” [s]?
Authors: Lombardo Danilo A. , Whalen D. H. , Chen Wei-Rong , Shadle Christine H.
Published: May 2022

The effect of syllable position on the acoustic structure of speech sounds has been studied for different consonants. A well-known example is the lateral approximant /l/ in American English (AE), whose spectral properties vary between initial and final position, as characterized by the light–dark [l] distinction, as in [l]eaf versus fee[ɫ]. Spectral differences between initial and final /l/ have been widely reported, with final [ɫ] displaying a higher concentration of acoustic energy in the low-frequency range. /l/ shares articulatory properties with the alveolar fricative /s/, and both sounds display similar trajectories of diachronic change at initial versus final position. However, it is unknown whether syllable position modulates the acoustic properties of /s/ in a way similar to that observed for /l/. We explored the AE /s/ in initial and final position using sVC and CVs words with symmetrical contexts. Acoustic parameters were computed from multitaper spectra. Preliminary results show that the amplitude at higher frequencies is less intense in final than initial [s]. Moreover, the frequency of the main spectral peak was lower in final [s]. It appears that similarities between /s/ and /l/ extend to the effect of syllable position on spectral properties.
Phonation in verbal tics and true words is distinguishable on the basis of voice quality
Authors: Llorens Mairym , Goldstein Louis
Published: May 2022

Adults with Tourette syndrome produce vocal tics that mimic true words and phrases. These verbal tics often occur while the ticcer is actively engaged in speaking. By virtue of their isomorphism with true words, co-speech verbal tics can introduce unintended meanings into a talker's utterances. How does the ticcer-talker compensate for the presence of intrusive verbal tics that threaten to confuse their interlocutor? In the present study, the acoustics of phonation in naturalistic co-speech ticcing by four adult speakers of English was examined. Six acoustic parameters previously identified as indices of the distinction between falsetto and modal voice were extracted from ticced and spoken stressed vowel and whole-word intervals. For all participants, at least three out of the six markers of falsetto were observed in verbal tics and were absent in true words. Furthermore, transitions into and out of falsetto were concomitant with transitions across speech-tic and tic-speech junctures, respectively. These results suggest that phonation tasks for verbal tics are aimed at achieving falsetto mode of laryngeal vibration, in contrast to phonation in spoken English, which is largely modal. Findings are interpreted in terms of a discourse-level task that organizes ticced and spoken vocalizations in the service of clear communication.
Towards a process description of acoustic uncertainty in the upper ocean
Authors: Colosi John A. , MacKinnon Jennifer
Published: May 2022

The upper ocean is a region that hosts the worlds largest biomass, is the boundary layer mediating the exchange of momentum, energy, heat, gasses, etc. between the air and sea, and it is a region of critical Naval tactical importance. Acoustic modalities are important tools for sensing this region as evidenced by the ground-breaking results of bio-acousticans monitoring whales, fish, zooplankton, and other marine organisms. But while the significance of upper ocean acoustics has been long appreciated, the understanding of key ocean acoustic processes is lacking. Here, we define upper ocean as the region of the water column where the impacts of winter mixing are evident, usually two to three times the depth of the maximum mixed layer. The classical view of the thermohaline structure posits a combination of mostly one-dimensional mixing processes, slow mesoscale stirring and advection, and subsequent subduction towards the main thermocline. However, a number of recent studies points to an important role played by three-dimensional, small-scale, rapidly evolving, submesoscale fronts and their potential interaction with internal waves. A few observational highlights will be reviewed with an emphasis on sound-speed and spice distributions, and implications for deterministic and stochastic sound propagation effects will be discussed.
Time frequency investigation and representation of acoustic backscatter signatures
Authors: Newcomb Wendy N.
Published: May 2022

Observation of an object’s structural acoustic response, considered in the aspect-dependent frequency response domain, is a data representation used for characterizing the target strength of an object. Geometric and elastic wave features in the angle-frequency domain are difficult to distinguish. Time varying characteristics such as attenuation are lost with a single frequency transform across the entire time collection of the acoustic return. Research in the aspect angle-frequency domain primarily applies the fast Fourier transform to an entire time series collection for a single ping cycle. This work aims to extend the dimensional space of analysis for the acoustic backscatter representation by investigating time-frequency resolution across aspect angle for acoustic elastic responses of an object. Empirical analysis of the data is presented with application of various time frequency transforms. These methods are assessed using time frequency localization metrics to quantify their performance with the AirSAS dataset. This exploratory work will develop the intuition regarding how the time frequency distribution can be localized, measured, and vary among objects of differing compositions. The ways in which time frequency localization can support distinguishing features of the acoustic return beyond the traditional aspect angle-frequency domain will be discussed as well.
The holographic signal processing for the estimation of sound mode parameters in shallow water
Authors: Pereselkov Sergey A. , Kuz'kin Venedikt , Kaznacheeva Elena , Kaznacheev Ilya
Published: May 2022

The holographic method for estimation of the broadband sound field modes parameters by using a single receiver in shallow water is presented in the paper. The holographic method of signal processing is based on the two-dimensional Fourier transform (2D-FT) of the source moving in the shallow water waveguide. The sound field creates in waveguide a stable interference pattern (interferogram) in the frequency-time domain. The result of the 2D-FT of the interferogram is called the Fourier-hologram (hologram). It is shown in the paper that different sound field modes create different focal spots in the hologram domain. The filtering focal spots and applying the inverse 2D-FT to them allows restoring the field of the selected mode. In relation to the time-warping operator, the proposed method of signal processing provides a smaller error in the mode group velocity estimation. The results of the numerical simulation as well as the sound mode parameters estimation are presented and discussed in the paper. [Work supported by the RFBR (19-29-06075) and МК-6144.2021.4.]
A multi-frequency sonochemical reactor utilizing a cylindrically focused acoustic wavefield for improved sonochemical efficiency
Authors: Raymond Jason L. , Roy Ronald A. , Kwan James
Published: May 2022

Sonochemistry involves several steps. First, an acoustic wave must be generated with sufficient energy to nucleate cavitation. This cavitation event must then be energetic enough to produce radicals through the sonolysis of the gas or vapor molecules in the bubble. Finally, these radical species must survive long enough to react with other chemical species to yield the desired product. The sonochemical efficiency (SE) is thus defined as the ratio of the product yield to the input acoustic power. Here, we put forward a novel approach to enhancing the SE by designing a multi-frequency (0.25 to 1MHz) sonochemical reactor that reflects a cylindrically spreading acoustic wave 180°. The reflected wave converges to cylindrically shaped high-intensity “hot zone” positioned along the axis of the reaction vessel. At modest power input, we detected noise with a passive cavitation detector in air-saturated water, suggesting the direct nucleation of cavitation. Using the Weissler reaction to determine the production of hydroxyl radicals, we determined the SE of our sonochemical reactor at various operation conditions. We also compared these values to conventional bath, horn, and plate sonochemical reactors. The comparison suggested that our reactor design had a better sonochemical efficiency for the Weissler reaction.
Phonetic alignment to regional variants in interaction
Authors: Eijk Lotte , Schriefers Herbert , Ernestus Mirjam
Published: May 2022

Alignment is the process of adapting speech to another interlocutor’s speech. We set out to explore whether speakers align phonetically to regional variants since no clear evidence has been reported (Gessinger et al., 2019; Earnshaw, 2021) and if so, what the driving mechanism is (local versus global context). We investigated phonetic alignment to two regional variants of a Dutch phoneme, known as the “hard g” or “soft g.” Participants interacted with two confederates differing in their regional variants in a sentence completion task (total of 268 sentences). In a pre-test, participants completed sentences by themselves. They then interacted with Confederate 1 (Round 1), with Confederate 2 (Round 2), and again with Confederate 1 in Round 3, and lastly by themselves again in the post-test. We investigated the duration and Centre of Gravity of the 15 085 fricatives of 36 participants. We examined three different predictors testing for differences between short-term and long-term alignment effects. None of these predictors showed significant effects of alignment. Descriptive analyses showed tremendous variation among speakers. We conclude that phonetic alignment of regional variants is not as clear as phonetic alignment previously demonstrated in less ecologically valid studies.
Triggering and spreading of lateral tongue posture
Authors: Liu Yadong , Gick Bryan
Published: May 2022

Lateral bracing is a tongue posture that is pervasively maintained during speech across languages (Liu et al., in press), released only for a few English sounds ([l] and occasional low vowels; Gick et al., 2017). While bracing is required for many (e.g., coronal) sounds, it is unclear why bracing is maintained during non-lingual sounds (e.g., labial/glottal consonants). Specifically, it is unknown whether bracing is maintained during non-lingual sounds because it is a pervasive default posture for speech (i.e., turned “on” unless actively suppressed, e.g., for /l/) or whether an unbraced posture can be maintained during extended periods. We collected coronal cross-section ultrasound imaging of the dorsal tongue while participants said “hubba-bubba” (a four-syllable sequence of non-lingual consonants and low vowels) in two contexts: surrounded by mandatorily braced sounds (e.g., /s/) versus unbraced sounds (e.g., /l/). Preliminary results show that the lateral tongue stayed in a lowered position throughout “hubba-bubba” when surrounded by unbraced sounds compared to braced sounds. Results suggest the lateral tongue may be held in one of at least two distinct postures whose activation is controlled by “trigger” events. [Work supported by NIH and NSERC.]
An ultrasound study of high vowel devoicing in Tokyo Japanese: Evidence for the vowel gesture retention
Authors: Iwasaki Rion , Roon Kevin D. , Shaw Jason A. , Tiede Mark , Whalen D. H.
Published: May 2022

High vowels in Tokyo Japanese are typically devoiced between voiceless obstruents, but controversy remains over whether vowel gestures persist when devoiced or are instead deleted. A previous ultrasound study (Iwasaki et al., 2020) showed that the lingual articulation of the release burst of /kV/ differs by vowel context even when the vowels are devoiced. This study uses tongue surface contours derived from midsagittal ultrasound images to investigate the effects of vowel devoicing on changes in quantified tongue shape over time. Native speakers of Tokyo Japanese produced word pairs (/C1VC2e/) that contrasted in the voicing of V, which was either /i/ or /u/. Tongue shape was characterized by Fourier transforming tangent angles along each contour (Dawson et al., 2016). Time-normalized trajectories over the /C1VC2e/ sequence were compared by vowel context (/i/ versus /u/) and voicing environment (devoiced versus voiced). Preliminary results show that the real component of the first Fourier coefficient is sensitive todetecting evolving shape differences between the two vowel contexts over the sequence, not just when the vowels are voiced, but also when they are devoiced. Based on these results, the high vowel contrast persists even in the devoiced environment, suggesting that devoiced vowels are not deleted.
Enhancing secondary voicing cues in words with minimal pairs
Authors: Bai Justin , Scarborough Rebecca
Published: May 2022

Lexical competition conditions phonetic variation. For example, words with more phonological neighbors are produced with more hyperarticulated vowels than words with fewer neighbors, and /p,t,k/-initial words with voiced stop minimal pairs have longer VOT. Such effects enhance contrastive features and may be aimed at improving perceptibility of more potentially confusable words. Secondary features may also help distinguish words, as with lengthened vowels that cue coda consonant voicing in English. Our study investigates whether secondary features are enhanced in the production of lexically confusable words, comparing vowel duration in words with final voiced consonants between words with and without minimal pair competitors (e.g., bag with minimal pair back vs. gag with no pair gack). Fifteen American English speakers produced 30 monosyllabic English words with voiced final consonants, half with minimal pair competitors and half without (matched for frequency and neighborhood density). Pre-voiced vowels were found to be longer in minimal pair words than in non-minimal pair words; interactions indicate that the effect is stronger for some vowels. These findings show that it is not just contrastive features, but secondary features too that are subject to enhancement in lexical competition contexts, since they too can contribute to successful lexical perception.
New England Shelf Break Acoustic (NESBA) experiment: Stochastic acoustic prediction
Authors: Stevens Bill , Siderius Martin , Carrier Matthew
Published: May 2022

Sonar performance prediction has been a topic of interest for decades. Predictions are based on acoustic propagation modeling that is typically deterministic, i.e., lacking quantified confidence or uncertainty bounds. While this may be adequate in some locations, in oceanographically complex regions it can result in misleading predictions and conclusions that sonar performance predictions are unreliable. A better approach includes explicit calculations of the underlying source, receiver, and environmental uncertainties to provide a prediction confidence level. In oceanographically complex areas, the resulting uncertainties are likely to be high; however, knowledge of this allows uncertainties to be managed. The NESBA Signals and Noise experiment was conducted in April–May 2021. The goal of the experiment was to assess the potential for sonar prediction effectiveness gains given improved environmental awareness. This talk addresses the NESBA sub-goal of demonstrating that high-resolution ocean modeling with ensemble forecasts (in this case, Regional NCOM) could be leveraged for stochastic acoustic predictions, resulting in increased accuracy in performance predictions with quantified uncertainty bounds. NESBA results will be presented leveraging the high-resolution ocean model forecasts with ensembles run concurrently with NESBA and the numerous temperature/salinity profiles taken during the experiment. [Work supported by the Office of Naval Research.]
Acoustic droplet vaporization and gas embolotherapy
Authors: Bull Joseph L.
Published: May 2022

We present an overview of our research group’s work in acoustic droplet vaporization and gas embolotherapy, including bubble and droplet dynamics, bioeffects, targeting of droplets, localized drug delivery, and selective occlusion of blood flow to tumors. In these applications, transvascular liquid perfluorocarbon droplets are injected intravenously and, subsequently, vaporized with ultrasound to selectively form vascular micro- and nano-bubbles that are used for therapy. The resulting bubbles are approximately 125 times the volume of the droplets from which they originate. Embolization of tumors with this methodology involves droplets that are sufficiently large to produce bubbles that will lead to occlusion. Drug-loaded droplet may be used without occlusion if they are sufficiently small. We have used a combination of theoretical, computational, and experimental approaches to elucidate the behaviors and mechanisms involved in acoustic droplet vaporization. In a murine model of hepatocellular carcinoma, we have demonstrated that the combination of gas embolization and chemotherapy can result in complete tumor regression.
In-group identity of a video narrator has no effect on instructional persuasiveness for undergraduates at a minority-serving technical university
Authors: Elliott Taffeta , Sharma Susmi
Published: May 2022

Identifying with upperclassmen may help undergraduates transition towards effective academic skills in college. We statistically compared two identity-related models of how video instruction could support students in adopting advantageous study habits in core math, science, and engineering programs. Each model relied on the same video animation and script about evidence-based study strategies for efficient learning (SSEL), presented in a first-semester required Composition class. SSEL in the in-group model were endorsed by a STEM-major upperclassman who introduced her experience improving her studies at the institution, before she narrated the video. The expert model version of the video was narrated by a trained voice actor who declared that cognitive psychologists espoused the same SSEL based on research. Volunteer participants were 136 undergraduates at a public technical 4-year Hispanic-Serving Institution (HSI). Video models were randomly assigned to each fall 2021 Composition class. Study habits were assessed on a 19-item pretest survey in the 4th week, just before students watched the video. They were assessed again using a parallel survey as a post-test in the antepenultimate week of the semester. Students reported significantly more SSEL in the posttest versus pretest. There was no significant effect of model, possibly due to student interest in science.
Experimenting with technologies in introductory musical acoustics classes
Authors: Dostal Jack A.
Published: May 2022

I have relied on a variety of programs and platforms to teach my introductory Physics of Music course online. Now that my students are back in person, some of the online/hybrid course modifications still work well for in-person delivery. I will describe the changes that managed to “stick” as well as some that did not. These include ways I have used conferencing platforms, free/open source programs, course learning management systems (LMS), and streaming services in my class.
Regression analysis of meteorological, aircraft trajectory, and ambient effects on sonic boom metric variability
Authors: Durrant J T. , Gee Kent L. , Anderson Mark C. , Cook Mylan R. , Loubeau Alexandra , Doebler William
Published: May 2022

NASA’s Low-Boom Flight Demonstration mission is a major step toward commercial, overland supersonic flight. Certifying low-boom aircraft will require accurate measurements, including understanding uncertainty due to variations in meteorology, aircraft trajectory, and measurement environment. This work builds on preliminary work done with Least Absolute Shrinkage and Selection Operator (LASSO) regression [Durrant et al., J. Acoust. Soc. Am. 150, A259 (2021)] to analyze the variability present in NASA’s Quiet Supersonic Flights 2018 (QSF18) dataset. With the variability quantified and several factors having been identified as potential contributors through LASSO regression, least-squares regression is used on sets of these potential contributors to determine coefficient weights for each factor, including meteorological, aircraft trajectory, and ambient noise. Sonic boom metrics are then predicted using the results and the accuracy is compared to PCBoom predictions. Because the ambient noise is significant, the same regression techniques are used to examine which variables from a geographic information systems (GIS) dataset are correlated with the ambient noise. These techniques are likely to be useful for noise monitor placement planning and data interpretation during community testing of low-boom aircraft. [Work supported by NASA Langley Research Center through National Institute of Aerospace.]
Aging effects on listening effort in cochlear-implant users
Authors: DeRoy Milvae Kristina , Abramowitz Jordan C. , Kuchinsky Stefanie E. , Goupell Matthew J.
Published: May 2022

Cochlear-implant (CI) users often report that listening to speech can be exhausting. Greater listening effort can occur with a degraded acoustic signal even in individuals with normal hearing, but age-related changes in auditory processing and individual differences in cognitive abilities may exacerbate the effort required to process a degraded signal. Therefore, we examined the effects of aging and individual differences in cognitive abilities on listening effort (measured with pupillometry) in two experiments. In the first experiment, we measured how changes in signal degradation (spectral resolution) affect listening effort in younger and older adults with normal hearing recalling CI-simulated (vocoded) sentences. In the second experiment, we examined how memory load and cognitive abilities (individual differences in working memory scores) affect listening effort in CI users recalling digit strings. It was hypothesized that increased effort would be observed with greater signal degradation, memory load, and age, and that individual differences would relate to working memory scores. Preliminary results are consistent with the hypothesized effects. These results support the clinical relevance of listening effort in older CI users and provide motivation for development of clinical practices to reduce listening effort in this population.
Phononic crystal with rigid scatterers: Infinite density versus infinite elasticity
Authors: Shymkiv Dmitrii , Krokhin Arkadii
Published: May 2022

Models involving materials with extreme parameters, while usually unreachable in practice, play important role in different areas of physics, for example, black body and ideal gas in thermodynamics, perfect conductor, and ideal diamagnetic in electrodynamics. In acoustics, the concept of rigid (or hard) scatterer is widely used to study propagation of sound in heterogeneous media with high-acoustic contrast between the constituents. Here, we report the results obtained for band structure calculations of phononic crystals with rigid scatterers. A scatterer with infinite acoustic impedance is modeled by approaching either the mass density (ρ) or the elastic modulus (λ) to infinity. It is shown, using the plane-wave expansion method, that in both cases the dispersion equation contains singular matrices with elements related to the form factor of the crystal lattice. However, this singularity does not affect calculations of the band structure in the case λ → □. Unlike this, in the limiting case of infinite density, the dispersion equation becomes meaningless. We explain the mathematical reason of this drastic difference and propose a regularization numerical procedure. Our general results are illustrated by a particular case of elastic superlattice when the dispersion relation is available analytically.
Perception in context: How racialized identities impact speech perception
Authors: Kutlu Ethan
Published: May 2022

When available, listeners use visual cues in speech perception [Zheng and Samuel (2017)]. However, it is not clear whether racialized identities impact listeners’ judgments, and if so, to what extent everyday experiences contribute to this. American, British, and Indian English varieties were paired with white and South Asian faces to test whether listeners’ intelligibility and accentedness judgments vary as a function of the faces that they saw and the varieties that they were listening to. A prior norming study was used to assess that sentences in all varieties had similar intelligibility. Listeners in a low-diverse environment (i.e., Gainesville, USA) versus a high-diverse environment (i.e., Montreal, Canada) were recruited. Racial diversity in listeners’ social network and their language diversity [i.e., language entropy, Gullifer and Titone (2020)] were measured. Results showed that listeners’ ability to transcribe sentences (i.e., intelligibility) decreased and their accentedness judgments increased for all English varieties when speech was paired with South Asian faces. Furthermore, these effects were modulated by participants’ social network diversity and their geographic context [Kutlu et al. (2021); (2022)]. We discuss the holistic impacts of the racialization of different language varieties and the role of multilingual and diverse context effects on speech perception.
The role of perceived ethnicity in speech processing: Insights from diverse populations and methods
Authors: Hanulikova Adriana
Published: May 2022

In this talk, I will discuss behavioral and electrophysiological studies that examine the extent to which perceived talker identity influences speech comprehension and evaluation. Two frequently discussed theoretical accounts lead to different predictions. Bias-based accounts assume conscious misunderstanding of a standard variety in the case of a speaker classification as nonnative, resulting in negative ratings and poorer comprehension. Exemplar-based models suggest that such effects arise only when a contextual cue to the social identity is misleading, i.e., when ethnicity and speech clash with listeners’ expectations. To address these accounts, and to assess ethnicity effects across different groups and methods, diverse non-university populations (172 monolinguals, 58 bilinguals, age range 12–92) were primed with photographs of Asian and white European women and asked to repeat and rate utterances spoken in three accents (Korean-accented German, a regional German accent, standard German), all embedded in background noise. In three electrophysiological studies, students (106 monolinguals, age range 18–30) passively listed to utterances in two accents (Turkish-accented and standard Dutch) and were either primed or not with photographs of a Turkic or a Dutch woman. The findings suggest that theoretical contradictions are a consequence of methodological choices, which reflect distinct aspects of social information processing.
Race, racialization, and racism in speech perception: Past, present, and future
Authors: Munson Benjamin , Tripp Alayo
Published: May 2022

Individuals make inferences about people’s race from the way they speak [Purnell et al. (1999)]. Moreover, people’s assumptions about individuals’ race shape the way that they perceive the form and content of the messages that people produce [Rubin (1992); Staum Casasanto (2008); McGowan (2015)]. In this talk, we step back from empirical studies on this topic and consider what it means to perceive a person’s race. Our work situates the perception of talker race in the framework developed by Tripp and Munson (2021) to explain social perception and language perception more generally. We argue that racialization involves distinguishing groups of persons, which are abstractly defined, with perception measures depending upon the racial categories participants believe are perceptible, real, desirable, powerful and normative. The parsing of individuals into different imaginary person-kinds emerges from beliefs about the significance of differences between body-minds. Individuals’ perception reveals an interplay among personally held ideologies, identities, and awareness of societally dominant narratives. We speculate on how these processes might have been at play in previous studies on the influence of race on speech perception. We provide a research agenda for robustly assessing the perception of person-kinds when studying how perceived race interacts with the perception of speech.
Sonar acoustic feature interpretation using braid manifolds
Authors: Sen Gupta Ananya , Kubicek Bernice , Christensen Andrew J. , Linhardt Timothy , Kirsteins Ivars
Published: May 2022

Autonomous target recognition has been a long-standing problem with complementary techniques based on classic subspace-based methods and recent machine cognition techniques proposed across several decades. Despite some success in both approaches, robust detection and meaningful interpretation of target features stay an open challenge. The primary bottleneck is the entanglement of multi-dimensional spectral features, some of which are intrinsic to target composition and geometry, and others originate from environmental reverberation and background clutter. This challenge is further compounded by unpredictable non-linear overlap between target features, which may themselves morph as a function of experimental conditions such as ping angle, range, frequency, and other factors. Furthermore, there is a compelling need to represent target features in a compact representation that lends itself to meaningful physical interpretation by a domain expert as well as robust interface with popular machine learning architectures. In this light, we will provide a broad overview of our recent and continuing work with braid manifolds, a morphological construct based on topological continuity of target features, that bridges this gap between physical model-based target representation and autonomous machine-learnt representation of target features. Representative results based on experimental field data on different target sizes and experimental conditions will be presented.
Broadband echolocation: From dolphins to drones
Authors: Andersen Lars N.
Published: May 2022

Broadband echolocation signals can be used to obtain detailed information about the underwater environment. The work performed by Whitlow W. L. Au on characterizing broadband clicks used by dolphins, studying the capabilities of the dolphin echolocation system, and exploring processing of the reflected signals has been and continues to be an important inspiration to the development and exploration of new echo sounder systems used by scientists world-wide to explore the oceans. This presentation will contain examples on Whit’s invaluable inspiration.
Is broad angular coverage necessary for echolocation-based discrimination involving aspect-dependent targets?
Authors: Lee Wu-Jung , Ladegaard Michael , Buck John R. , Madsen Peter T. , Beedholm Kristian , Tyack Peter
Published: May 2022

Building on the foundation of Dr. Whitlow Au’s pioneer and extensive work on the sonar of dolphins, recent research has illuminated the dynamic nature of echolocation involving free-swimming toothed whales. The sophisticated orchestration of movements and biosonar outputs by toothed whales is particularly relevant in the context of developing agile autonomous sonar-guided underwater vehicles. In this study, we test the hypothesis that broad angular coverage, which provide comprehensive echo information of aspect-dependent objects, is necessary for target discrimination via echolocation. We trained a harbor porpoise to actively approach and select a sphere against a spheroid in a two-alternative forced-choice target discrimination task in a net pan. Two spheroids of different aspect ratios representing two overall difficulty levels were used with each presented at diverse orientations when paired with the sphere. We show that the porpoise can discriminate these targets without acquiring aspect-dependent spheroid echo information over broad ranges of angles. Instead, focused, rapid sampling via buzzes appears to aid discrimination in more challenging scenarios. These results suggest that echolocation-based discrimination involving aspect-dependent objects is possible based on subsets of echo signatures without more extensive angular sampling that could build toward an understanding of the target identity. [Work supported by ONR.]
WAU! Identifying complex objects with an acoustic flashlight?
Authors: Harley Heidi E.
Published: May 2022

A Hawaiian bunker, a bearded and barefoot entrepreneur, some dolphins, and an electrical engineer: A starter recipe for one of the most productive dolphin biosonar researchers in world history? Sound unlikely? Overstated? Apocryphal? And yet… Thirty years with Whit inspired us to investigate a dolphin’s use of wholistic shape matching versus “flashlight” object-parts-focused matching. Our stimuli were 3 3-object sets (Sets W, A,U). Objects within sets varied on shape alone made with identical PVC parts, but PVC parts varied between sets. In Condition Shape, experienced dolphin Calvin matched objects based on shape within sets (matching W1Snail to W1Snail) in a 3-alternative echoic matching-to-sample task: mean accuracy across 12 18-trial sessions/set: Set W: 37%, Set A: 44%, Set U: 39%, chance = 33%. In Condition Parts/NoShape, Calvin performed untrained transfer tests with same-parts/different-shape objects as sample-match pairs within alternative arrays of objects from different sets with different parts (sample W1Snail matched to W2StingRay with alternatives A2Trumpet and U2Whale). Mean accuracy in ten transfer sessions/set (WAU1 to WAU2: 47%, WAU2-WAU3: 48%, WAU3-WAU1: 39%) was above-chance and comparable to Condition Shape even though shape information was absent for matching in this parts-focused condition. Calvin’s narrow echolocation beam may have emphasized object parts versus wholistic shape.
A novel ultrasound-assisted laser technique to remove atherosclerotic plaques
Authors: Singh Rohit , Yang Xinmai
Published: May 2022

Atherosclerosis is a medical condition in which arteries hardens and narrows due to the buildup of fat, cholesterol, calcium, and other substance. It can affect arteries of heart, brain, arms, legs, pelvis, and kidney, resulting in ischemic heart disease, carotid artery disease, peripheral artery disease, and chronic kidney disease. Laser based treatment techniques like laser angioplasty and carotid artery laser endarterectomy can be used to treat most common atherosclerosis disease like ischemic heart disease and carotid artery disease. Excimer laser coronary angioplasty (ELCA) is a clinical technique to remove the arterial plaque. However, the use of ELCA remains low due to higher risk of complication and its low efficacy in removing plaques as compared with balloon angioplasty. In this study, we developed a novel technology that uses ultrasound along with laser to assist the removal of atherosclerotic plaque. Spatio-temporally synchronized pulsed laser and ultrasound was used. The preliminary experiments were performed on pig belly fat sample to find the optimal ultrasound and laser parameters. The final experiment was performed on the plaque samples collected from patient during carotid endarterectomy procedure. Our results show that the addition of ultrasound can effectively reduce the needed laser power, which could result in improved treatment safety and efficiency.
Optical breakdown in holmium:YAG laser lithotripsy
Authors: Pishchalnikov Yuri A. , Behnke-Parks William M. , Stoller Marshall L.
Published: May 2022

Optical breakdown produces shock waves and cavitation and is typically observed with the Q-switched lasers. In contrast, the free-running mode holmium:YAG laser lithotripters produce long (>150 μs) laser pulses that were reported to break urinary stones via thermal decomposition of stones and explosive vaporization of interstitial water without optical breakdown. Here, we show evidence of optical breakdown in holmium:YAG laser lithotripsy using fine temporal and spatial resolution of ultrahigh-speed video microscopy. Images were collected with a Shimadzu HPV-X2 camera at rate up to 10 million frames per second. Infrared- and visible-light photodetectors (10-ns rise time) resolved temporal profiles of infrared laser pulses and visible sparks indicative of optical breakdown. Hydrophone measurements showed shock waves produced by optical breakdown and subsequent collapses of vapor bubbles, capable of breaking glass microscope slides with a single laser pulse. Optical breakdown was observed with the laser fiber tip in contact with synthetic and whole surgically retrieved urinary stones. These observations suggest that the previously unappreciated optical breakdown with holmium:YAG lasers can be an additional acoustic mechanism of action in laser lithotripsy, currently the most used treatment modality for urinary stones, and in other laser procedures. [Work supported by NIDDK of NIH under Award No. R43DK129104.]