bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity to AM incoherence is affected by center frequency and modulation rate
Authors: Whiteford Kelly L. , Oxenham Andrew J.
Published: April 2019

Fine-grained sensitivity to frequency modulation (FM) at slow rates and low-frequency carriers is thought to be due to auditory-nerve phase locking (time code). Alternatively, a unitary code for FM at all rates and carrier frequencies could be based on cochlear conversion of FM to amplitude modulation (AM) (place code). One weakness of the place-coding theory is it cannot readily explain rate- and carrier-dependent trends in FM sensitivity. This study asked whether FM trends could potentially be explained by sensitivity to two AM envelopes that are out of phase (incoherent AM) at separate cochlear locations, thereby simulating the effects of FM. AM discrimination was assessed for two-component complexes centered at low (500 and 1500 Hz) and high (7000 Hz) frequencies, spaced 2/3 or 4/3 octaves apart, and modulated at slow (2 Hz) and fast (20 Hz) rates. Coherent and incoherent two-component AM detection was assessed for the same conditions. Preliminary results show that sensitivity to AM incoherence is best at low center frequencies and slow rates, consistent with trends traditionally found in FM detection that have been attributed to time coding. Findings suggest time coding may not be necessary to explain trends in FM sensitivity. [Work supported by NIH Grant R01DC005216.]
Harmonicity aids detection of speech and other sounds in noise
Authors: McPherson Malinda J. , McDermott Josh
Published: April 2019

Acoustic grouping cues, such as the tendency of frequencies to be harmonic, are used to segregate multiple sounds, as when listening to one of several concurrent speakers. However, we often must listen to sound sources in noise. Here we investigate the role of traditional acoustic grouping cues in detecting sound sources in noise. We measured detection thresholds for several types of sounds embedded in noise: speech, musical instruments, and synthetic complex tones. In each case the sounds were resynthesized with harmonic and inharmonic carrier frequencies to test the importance of harmonic frequency structure for hearing in noise. We found that harmonic signals were consistently easier to detect in noise than otherwise similar inharmonic signals. This harmonic advantage persisted even when the phases of harmonic components were randomized, such that the advantage is unlikely to reflect differences in the depth of modulation (from beating). Near threshold, harmonic signals were readily audible in conditions where inharmonic signals could not be heard. These results suggest that harmonicity is critical for detecting real-world signals in noise, demonstrating its relevance to another important aspect of auditory scene analysis.
Does lateral position explain release from informational masking arising from interaural time and level differences?
Authors: Freyman Richard L. , Milkey Casey D. , Buss Emily , Zurek Patrick
Published: April 2019

Spatial release from masking (SRM) is known to arise from the interaural time and level differences (ITDs and ILDs) produced by spatially separated signal and masker sources. In some situations, SRM might be augmented considerably by the differing spatial perceptions created by the signal and masker, which could help alleviate confusions between them. Using headphone presentation, the present study investigated this hypothesized perceptual component of SRM. Maskers were binaural click trains of approximately 2-s overall duration with inter-click intervals (ICIs) varying randomly between 50 and 150 ms. The ITD or ILD of the masker clicks was manipulated across listening blocks. The listeners’ task was to identify the number of signal clicks, identical to the masker clicks except for their ITD/ILD, inserted during masker inter-click intervals. Preliminary testing with a fixed masker ICI demonstrated that the signal clicks were easily audible, strongly suggesting that difficulty during the main identification task was due to confusions from the randomized ICI. The study explored whether performance counting signal clicks in the randomized ICI conditions could be explained by the differences in intracranial spatial perception created by combinations of ITD and ILD cues. [Work supported by NIDCD R01 01625.]
Revisiting superoptimal perceptual integration for pitch at high frequencies
Authors: Gockel Hedwig E. , Carlyon Robert P.
Published: April 2019

In a frequency discrimination task, Lau et al. [J. Neurosci. (2017)] reported superoptimal integration of information from individual components in a very high frequency region, where phase locking to the temporal fine structure is presumably absent, when the components were combined into a harmonic complex. We tried to replicate this finding using stimuli identical to those of Lau et al., with some additional conditions. Using an adaptive two-alternative forced-choice procedure, we measured fundamental frequency difference limens (F0DLs) for complex tones containing harmonics 6–10 with F0s of 280 and 1400 Hz, and frequency difference limens (FDLs) for each harmonic of the complex presented alone. Stimulus duration was 210 and 1000 ms. All tones had random phases, a ±3 dB level rove, and were presented in a continuous threshold-equalizing noise that was either diotic or dichotic. Observed DLs were lower overall than in the study of Lau et al. As in their study, for the low F0, observed F0DLs were worse than predicted assuming optimal combination of frequency information from the individual harmonics and assuming that performance is limited by peripheral noise. However, for the high F0, observed and predicted F0DLs did not differ significantly, in contrast to the finding of Lau et al.
A harmonic-cancellation-based model to predict speech intelligibility against a harmonic masker
Authors: Prud'homme Luna , Lavandier Mathieu , Best Virginia
Published: April 2019

This study aimed at predicting speech intelligibility in the presence of harmonic maskers. Contrary to a noise signal, these maskers have a harmonic structure that allows for a segregation of the competing sounds based on a difference of their fundamental frequency (F0). This F0 segregation could be due to spectral glimpsing or harmonic cancellation. It is unclear what the relative contributions of these two mechanisms are. In this work, we have modified the model of Collin and Lavandier [J. Acoust. Soc. Am. 134, 1146–1159 (2013)] in order to take into account both mechanisms. Different implementations of the model were compared and applied to two data sets: SRTs measured for monotonous harmonic maskers that varied in their F0s and degree of harmonicity; SRTs measured for monotonous and intonated harmonic maskers that varied in their mean F0, F0 contour, temporal envelope and spatial position. Comparison of data and model predictions will allow us to establish how to implement harmonic cancellation in our model framework, to evaluate to what extent the model can predict F0 segregation for harmonic maskers, and to determine the relative roles of spectral glimpsing and harmonic cancellation suggested by the model.
Pre-trial and post-trial cueing of masker location in a localization-in-noise task
Authors: Simpson Brian , Gilkey Robert H. , Wang Michelle , Spencer Nathaniel , Thompson Eric R.
Published: April 2019

Localization accuracy for a target presented in a simultaneous masker, whose location varies randomly from trial to trial, improves when a preview of the masker location is provided (by playing a sound from that location) prior to the target + masker interval (i.e., a pre-trial cue) [B. Simpson, Ph.D. dissertation (Wright State University, 2011)]. One explanation is that knowing the masker location allows a listener to establish a “spatial attention filter” at the masker location. The present study compares the effect of such a pre-trial cue to the case in which the cue comes after the target + masker interval (post-trial cueing). That is, the cue is presented either 500 ms prior to the onset of a 60-ms, 100-Hz click-train target embedded in a 60-ms broadband masker, or 500 ms subsequent to the offset of the target + masker stimulus. The data indicate that both cue types lead to similar improvements in performance over the no-cue condition, with the greatest improvement from cueing (~6 dB) seen for localization in the left/right dimension. While these data are roughly consistent with previous results, they cannot be explained by a simple spatial filter hypothesis.
Spatial external noise and detection
Authors: Pastore M. Torben , Yost William
Published: April 2019

In vision, a change in target position can cause an otherwise stationary target to perceptually “pop out,” thereby increasing its detectability. Previous work in this lab and others has shown that there is no corollary effect for auditory detection. The explanation most often given for this “null result” is that, while vision is encoded spatiotopically, audition is encoded tonotopically, and therefore changes in sound source position should not be expected to impact auditory detection in the way that target movement affects visual detection. This argument assumes that detection is largely a peripheral task. However, Green, Watson, and others have shown that auditory detection is affected by listener uncertainty about the frequency of presented target tones—this “external noise,” in terms of frequency, suggests that detection involves processing at higher levels beyond the periphery (e.g., attention). It therefore stands to reason that auditory target stimuli may be less detectable when sound source location is randomized—a spatial manifestation of external noise. We will present data testing this hypothesis.
Evaluation of metamaterial unit cell analysis techniques
Authors: Hanford Amanda , Beck Benjamin , Stearns Aaron J. , Wixom Andrew S.
Published: April 2019

The field of acoustic metamaterials has produced novel materials in a wide variety of applications. An important step in designing a metamaterial is unit cell analysis with subwavelength geometry. There are several techniques used for unit cell analysis when designing acoustic properties of interest for metamaterial applications. Such techniques include, but are not limited to, band diagrams, effective material properties, or half-space homogenization. This talk discusses the challenges and tradeoffs between analysis techniques and types of structures that lend to one method or another. Unit cell analysis methods will be evaluated to perform trade space exploration, including validation and parametric studies for metamaterial design.
A Lagrangian formulation of metamaterial homogenization
Authors: Muhlestein Michael B.
Published: April 2019

Many metamaterials may be well described as multi-scale systems where the large scale is represented by the wavelength and the small scales are represented by inhomogeneity lengths. The effective material properties of a metamaterial of this sort may be derived by considering the averaged behavior of material elements that are considered “infinitesimal” relative to the wavelength but is on the order of the inhomogeneity lengths. The averaging of the small-scale features enables a straightforward process to describe the metamaterial mechanics in terms of a Lagrangian formalism, and the macroscopic constitutive equations may be obtained by deriving the Euler-Lagrange equations for the macroscopic field quantities. This energetic approach to homogenization may be used to estimate both linear and nonlinear material properties. This talk describes this homogenization method for one-dimensional systems and compares the resulting effective material properties with other homogenization methods.
Measurement of additively manufactured anisotropic three-dimensional underwater pentamode materials
Authors: Cushing Colby W. , Wilson Preston S. , Haberman Michael R. , Su Xiaoshi , Norris Andrew
Published: April 2019

Pentamode (PM) materials are three-dimensional (3D) elastic lattice materials that can be designed to match the acoustic impedance of water while also minimizing shear modulus of the sample over wide frequency ranges. Further, the lattice structure provides the degrees of freedom necessary to produce strongly anisotropic stiffness that is useful for transformation acoustics [Su et al., J. Acoust. Soc. Am. 141(6) (2017)]. In the current work, anisotropic sub-wavelength 3D metallic PM samples were fabricated using additive manufacturing for measurement of their effective material properties. The samples were distributed uniformly in a one-dimensional, water-filled resonator tube. An electrodynamic shaker excited the system and the system response was recorded using a hydrophone positioned near the top of the tube. The resulting resonance frequencies were then used to infer the phase speeds for each mode in the fluid-filled elastic waveguide. Two effective medium models were used to infer the PM-water mixture properties: (i) Wood-Mallock mixture law and (ii) a self-consistent micromechanical model that explicitly considers material anisotropy. Experimental results are compared with simulations and observations are drawn on material property extraction using the resonance tube technique when elastic anisotropy is present. [Work supported by ONR.]
ManyBabies1 part 2: Influences of language experience on infant-directed speech preference
Authors: Soderstrom Melanie , Byers-Heinlein Krista
Published: April 2019

ManyBabies1, our first effort at a large scale collaborative infant experimental study, provided a conceptual replication of the well-known phenomenon of infant preference for the characteristics of Infant-directed speech (IDS). One important question that has largely been unanswered by extant literature is how much the IDS preference is dependent on experience with a specific language. How do infants respond to IDS that is in a non-native variety, and how does their listening affect this preference? ManyBabies 1 used a consistent stimulus set of North-American English (NAE), which allowed us to answer this questions using two approaches. First, because participating ManyBabies 1 labs were located around the world, we were able to compare monolingual infants from a range of native-language backgrounds. We found that the preference for North American English IDS was larger for infants whose native language was NAE than for infants who had a different native language. Second, we conducted a sister project, ManyBabies 1 Bilingual, which tested infants from a variety of bilingual backgrounds. Bilinguals have similar total language experience and maturation as monolinguals, but their experience is divided across two or more languages. Planned analyses will examine monolingual-bilingual differences, and “dose-response” effects of exposure to NAE.
Effects of hearing loss and amplification device on infants’ perception of infant-directed speech
Authors: Bergeson Tonya , Wang Yuanyuan , Houston Derek
Published: April 2019

Caregivers typically speak to their infants in a speech register known as motherese or infant-directed speech (IDS; Fernald and Simon, 1984; Snow, 1977). Infants also prefer to listen to IDS over adult-directed speech (ADS) (Cooper and Aslin, 1990; Fernald, 1985; Singh et al.). Moreover, mothers adjust their IDS to factors such as infant age (e.g., Kitamura and Burnham, 2003; Newman and Hussain, 2006). Another factor that could potentially affect mother-infant interactions is infant hearing loss. Studies have shown that mothers adjust their speech based on infants’ hearing experience (e.g., Bergeson et al., 2006; Kondaurova and Bergeson, 2011; Wieland et al., 2015). Do infants with hearing loss pay attention to IDS? Two recent studies suggest that infants who use hearing aids or cochlear implants demonstrate increased attention to IDS over both ADS and silent trials (Wanget al., 2017; 2018). One feature that might regulate infant attention, namely target word repetition, is correlated with vocabulary skills in later childhood (Wang et al., in preparation). In this talk, we will address infants’ attention to speech and the role IDS serves in both cognitive-social and linguistic development for typically hearing infants and those with hearing loss.
Daylong acoustic recordings of family and child speech using the HomeBank database
Authors: VanDam Mark , De Palma Paul , Soderstrom Melanie , Casillas Marisa , Cristia Alex , Bergelson Elika , Warlaumont Anne , Olds Daniel , MacWhinney Brian
Published: April 2019

HomeBank (https://homebank.talkbank.org/) is an online database of multi-hour, naturalistic audio recordings of child and family everyday experiences. Corpora in the database include (1) raw audio recordings; (2) corpus metadata including for example social details, standardized test scores, disability reports and status, family data such as number and quantity of siblings, orthographic transcriptions, output of diarization or automatic-speech recognition processing; and (3) tools for analyzing the data (https://github.com/homebankcode/) in a variety of domains. There are currently over a dozen corpora representing over 1100 multi-hour (often daylong) audio recordings. Use of the database is increasing in the scientific community, including researchers of speech, language, computer science, digital signal processing, automatic speech recognition, health sciences, and human development. The utility and extensibility of HomeBank is demonstrated in this talk with several current and ongoing projects that make critical use of the data. We discuss diarization and automatic speech processing techniques, speech and language use in pre-industrial families and groups, early perception and processing in infants, family speech and language dynamics in families of children with disorders, and database management. We are actively soliciting both users and contributors to the database.
Temporal coordination of vocal turn taking between mothers and their children with hearing loss
Authors: Kondaurova Maria V. , Smith Nicholas A. , Zheng Qi , Reed Jessa , Fagan Mary K.
Published: April 2019

Normal-hearing (NH) infants participate in social exchanges soon after birth. What does vocal turn-taking look like in children with hearing loss after cochlear implantation? The study examined the prevalence and temporal structure of vocal turns during spontaneous interactions between mothers and their children with cochlear implants (CIs) over the first year after implantation compared to interactions between mothers and children with normal hearing. Mothers’ play with children with CIs (n = 12) were recorded at 3 (mean age 18.3 mo) and 9 (mean age 27.5 mo) months post CI. Mothers with age-matched hearing children (n = 12) were recorded at the corresponding time points. The CI group initially differed from the NH group in several ways (i.e., fewer vocal turns, more simultaneous speech, and longer between-speaker pauses) but progressed to NH levels by 9 months post CI, demonstrating the positive effects of CIs. Dyadic effects were also observed in the timing of mothers’ responses, which were related to those of their children. However, children with CIs continued to show an atypical pattern in the relative timing of between- vs within-speaker pauses across both test sessions, indicating a potentially protracted time course for the influence of CIs on dyadic interactions.
Performance weighted blending of nested array processors
Authors: Tucker Jeff , Wage Kathleen E.
Published: April 2019

Nested arrays consist of two uniform subarrays: a short aperture array with half-wavelength spacing and a long aperture array with greater than half-wavelength spacing. Two approaches for estimating the scanned response require computing either the product or the minimum of the subarray responses in each look direction. In multi-source environments, the multiplicative and min scanned responses may be corrupted by cross terms [Wage, Acoustics Today (2018)]. When the sources are uncorrelated, snapshot averaging is often used to mitigate cross term interference. The min processor's response can contain cross terms that do not decay with snapshot averaging. Alternatively, the multiplicative processor’s response contains cross terms that decay, though large numbers of snapshots may be required for the cross terms to fall below the level of those in the min processor. This talk proposes a performance weighted combination of the two processors based on Buck and Singer's (IEEE, 2018) blended dominant mode rejection beamformer. The same performance weighting function can be used to combine the nested multiplicative and min processors. The resulting universal processor adjusts the weighting in each look direction as the number of snapshots increases to favor the multiplicative processor as its cross terms average out. [Work supported by ONR]
Post-processing for underwater active detection and experimental results
Authors: Ma Lin , Zhao Anbang , Ge Chunsha
Published: April 2019

In practical engineering, the target echo signals are commonly corrupted by noise and strong interferences that severely degrade the active detection performance. In the presence of noise and interferences in the detection results, the target trajectory cannot be easily recognized. A post-processing method is proposed to cancel the noise and interferences and to make the target trajectory better to be characterized. In accordance with the difference between noise and signal, a width discriminator is used to filter out some fake peaks appeared in the detection output. Considering the environmental effects, the format-based method is used to reduce the stationary interferences, for instance, reverberation due to rocks on the bottom. The post-processing method is employed and investigated in a target underwater detection experiment. The experimental results indicate that the post-processing is effective in active detection for an engineering application.
Use of frequency-difference beamforming for scatterer localization
Authors: Douglass Alexander S. , Markley Kely J. , Dowling David R.
Published: April 2019

Acoustic fields interacting with discontinuities or environmental variations lead to secondary scattered fields superimposed onto incident fields. As a result, the signal measured at a remote receiving array will be modified by the scatterer’s presence. Prior work has shown that the effects of strong random scattering are reduced using frequency-difference beamforming to downshift the analysis to a below-band frequency known to be less impacted by scattering. In some applications, information about a scatterer is desired, such as location, shape, or composition. However, a relatively weak scattered field from a single scatterer is difficult to detect when the incident field dominates the measurements, as both conventional and frequency-difference beamforming ambiguity surfaces primarily provide the incident field’s source information. Here, a subtraction-based algorithm is implemented with frequency-difference beamforming to locate the position of a single scatterer near a source. Simulations and water tank experiments with a 110 kHz center frequency signal are considered for incident and scattered fields with a 4 cm diameter spherical scatterer, where the scattered field’s received energy is roughly 2% that of the incident field. The ability to downshift the frequency demonstrates a more robust implementation of subtraction-based algorithms for locating weak scatterers without prior location knowledge. [Work supported by ONR.]
Statistical characterization of cross terms in snapshot-averaged multiplicative processors
Authors: Chavali Vaibhav , Wage Kathleen E.
Published: April 2019

Multiplicative processors generate spatial spectrum estimates for sparse arrays, such as nested and coprime arrays, by multiplying the beamformed outputs of two interleaved subarrays. Nested and coprime arrays achieve significant sensor savings compared to dense Uniform Linear Arrays (ULAs) since one or both subarrays are undersampled. Chavali et al. show that careful design of the subarrays and proper selection of beamformer weights can guarantee power pattern performance (response to single planewave source) comparable to a conventional ULA processor [JASA (2018)]. The multiplicative processors’ response to multiple sources contains cross terms that appear as erroneous sources in the spectral estimate. The height of cross term peaks in the spectrum depends on the subarray design, beamformer weights, and signal powers. Ksienski and Pedinoff show that averaging the multiplicative processor output over snapshots reduces the power of uncorrelated cross terms [IEEE (1962)], though they do not explore how much averaging is required. This talk derives the statistics of the averaged cross terms assuming complex Gaussian planewave signals and noise. The statistical model is used to predict the number of snapshots required to eliminate uncorrelated cross term peaks from the multiplicative spectra. Analytical predictions show excellent agreement with planewave simulations. [Work supported by ONR.]
Nested sensor array extension factors required to match the peak sidelobe height of a uniform linear array
Authors: Elsaadawy Hossam , Houte Kayla M. , LeBlanc Camille , Slezak James M. , Adhikari Kaushallya
Published: April 2019

Nested sensor arrays (NSAs) are a type of non-uniform linear array (NULA) that reduce the total number of sensors used for a given aperture and retain the same resolution of a uniform linear array (ULA) [Pal and Vaidyanathan, 2010]. The peak sidelobe (PSL) height fails to fall below the acceptable standard of -13 dB associated with ULAs for basic NSA configurations. The basic NSA can be extended by a factor to improve the PSL height. Coprime sensor arrays, a related NULA design, have established sensor extension factors that have been found to reduce the PSL height to this -13 dB standard [Adhikari et al., 2014]. For NSAs, such an extension factor has not been established. This research finds the parameters required to extend an NSA to adequately reduce the PSLs. NSAs can significantly reduce the number of sensors required to yield a satisfactory beampattern, as low as twenty-five percent of the total aperture for some cases. Considering various array apertures, certain configurations successfully use a distinctly small aperture but require a higher percentage of those to be active. To verify our results, we construct a sixty-four sensor microphone array with which we test the optimal configurations. [Work supported by Louisiana Tech University.]
Improving autonomous vehicle safety—Using acoustic source localization to influence the decision making capabilities of an autonomous vehicle
Authors: Iglesias Digno , Matriss Anthony , Tatoglu Akin , King Eoin A.
Published: April 2019

The manner in which autonomous vehicles (AVs) and other vehicles will coexist, and communicate with one another, is still unclear, especially during the prolonged period of mixed vehicles sharing the road. During this time, it will be important that AVs are equipped to respond to acoustic alerts in urban environments. Consider the case of an emergency vehicle in a city. In this situation, a visual perception system alone will not suffice, as it requires a direct view of the source. The goal of this ongoing project is to define a new set of audio-visual detection and localization tools to identify the location of an unexpected rapidly approaching emergency vehicle. In particular, this paper focuses on the localization of a sound source in a complex environment by combining a ray tracing approach with a direction-of-arrival algorithm. This algorithm reports a number of source directions, arising from multiple reflections in the environment. Results are combined with a three-dimensional map, acquired live from a mobile robot equipped with digital sensors including LiDAR, and a reverse ray tracing approach is used to triangulate the likely position of the source.
The real-time dynamics of child-directed speech: Using pupillometry to evaluate children’s processing of natural pitch contours
Authors: Nencheva Mira L. , Piazza Elise A. , Lew-Williams Casey
Published: April 2019

Young children prefer child-directed speech (CDS) to adult-directed speech (ADS) (Cooper and Aslin 1990), and its structural and prosodic features are known to facilitate learning (Thiessen et al., 2005; Graf Estes and Hurley, 2013). However, little is known about how the real-time dynamics of CDS prosody affect young children’s engagement and learning. In Experiment 1, we evaluated moment-to-moment processing of pitch variation using measures of pupil size synchrony across children (Kang and Wheatley, 2017). 24-to-30-month-old children listened to a story in CDS and ADS, and we found that pupil synchrony was higher for CDS than ADS. Next, using hierarchical clustering, we uncovered 4 main word-level pitch contours from a natural CDS corpus and identified contours (specifically, U- and inverted-U-shaped contours), which elicited lower vs. higher synchrony, respectively. In Experiment 2, we found that children learned novel words better when they were presented in higher- vs. lower-synchrony contours. Importantly, synchrony for a novel word during training significantly predicted learning for the same word at test. By revealing a physiological response that is sensitive to the real-time dynamics of prosody, this investigation yields a new subsecond framework for understanding children’s engagement with a signal known to support early language learning.
Separability of infant-directed from adult-directed speech is affected by number of channels in cochlear-implant simulated speech
Authors: Arjmandi Meisam K. , Dilley Laura , Wang Yuanyuan , Svirsky Mario , Lehet Matt , Houston Derek
Published: April 2019

Many studies have demonstrated benefits of infant-directed speech (IDS) over adult-directed speech (ADS) for language development. For deaf children who use cochlear implants (CIs), a variety of factors might reduce the advantage of IDS in language development. We hypothesized that spectral degradation due to the number of channels in CI processing negatively affects acoustic separability of IDS and ADS, potentially reducing benefits for language development of IDS in early childhood. 493 sentences spoken in two speaking styles (IDS and ADS) were processed using 4, 8, 12, 16, 22, and 32 channels noise-vocoders to simulate the spectral degradation caused by CIs. The sentences were partitioned into frames of 30 ms and represented by Mel-frequency cepstral coefficients. The Mahalanobis distance was used to calculate the acoustic distance across speaking styles (ID versus AD) and processing condition (4, 8, 12, 16, 22, and 32 channels). The results show that spectral degradation imposed by CI processing has significant negative effects on separation of IDS from ADS. These findings suggest that the spectral information in speech received by infants with CIs is substantially degraded, which can weaken the facilitative link between IDS and language development in this at-risk population. [Work supported by NIH grant R01DC008581.]
Logging while drilling shear sonic logging in very large boreholes
Authors: Blyth Matthew , Sakiyama Naoki , Yamamoto Hiroaki , Oshima Atsushi , Saenz Eduardo
Published: April 2019

As LWD sonic tools have become more advanced, they have become more routine in use and are now commonly used in multiple hole sections, with the results having applications across a wide range of problems in well construction. The acquisition of quadrupole shear measurements in large boreholes and slow formations is highly challenging however, due to the borehole conditions, the very slow formation shear values and the effects of the drilling fluid. This paper will discuss the limits of the measurement under these conditions, using both modeled data and real well examples and the effect on measurement quality as a result of these conditions will be shown. The modeling studies shown indicate the importance of understanding the drilling mud properties (slowness and density) was well as the formation and borehole properties when attempting to derive robust shear information under these conditions. The results show that, although the acquisition of reliable shear data in these conditions is challenging, it is not impossible, provided that the LWD tool is correctly designed, the physics are understood and suitable processing applied.
Borehole sonic array processing and the group versus phase velocity debate
Authors: Assous Said , Linnett Laurie , Elkington Peter
Published: April 2019

We consider the impact of processing method on the ability to differentiate between group and phase velocity in dipole sonic log data. A new array processing method is used to demonstrate that the choice of processing algorithm could lead to confusion. We emphasise the importance of knowing the limitations of the processing method used before interpreting results and applying them to the calculation of elastic rock properties. The proposed method addresses the confusion and clarifies that what is computed from the array waveforms can be either group or phase velocity depending on the algorithm used and the formation properties in the given situation. We demonstrate the effectiveness of the approach versus conventional processing methods on synthetic examples.
Time warping and acoustic characterization of the seafloor in horizontally inhomogeneous ocean
Authors: Godin Oleg A. , Katsnelson Boris , Tan Tsu Wei , Malykhin Andrey
Published: April 2019

Time-warping transform is increasingly employed in shallow water acoustics to separate the field due to a compact, broadband sound source or the two-point cross-correlation function of diffuse noise into their normal mode components, and to measure mode travel times as a function of frequency. The time-warping transform was developed for range-independent waveguides, while physical parameters of the ocean are never quite constant in the horizontal plane. Bathymetry variations are typically responsible for the bulk of the waveguide’s range dependence as well as horizontal refraction of sound in the coastal ocean. Simple, exactly solvable models of shallow-water waveguides are used in this paper to illustrate the effects that the range dependence and horizontal refraction have on the performance of the warping transform and on the inferred geoacoustic parameters. Horizontal refraction due to generic bathymetric variations is addressed in the adiabatic approximation using perturbation techniques. Theoretical predictions are verified using numerical simulations. It is found that moderate bottom slopes can lead to large errors in retrieved geoacoustic parameters and cause positive bias in bottom sound speed estimates if horizontal refraction is ignored. [Work supported, in part, by NSF and BSF.]
The acoustic world of odontocete biosonar and technical sonar
Authors: Roan Michael J. , Müller Rolf , Lee Hyeon
Published: April 2019

Bats, toothed whales (odontocetes), and man-made sonar all use the same acoustical principles of echo-location. The fundamental components of these systems include transmitter frequency response, tailored waveforms, properties of a propagation medium, clutter, background noise, target strength, and receiver properties. Across all of these elements, there are very large differences (i.e., underwater versus in-air propagation). This gives rise to several interesting questions about the performance of these sonar systems. For example, given the bandwidth and duration of transmitted signals for bats and odontocetes, what are the relative target strengths/maximum imparted Doppler shifts for common prey types? How does the ambiguity function of the echo compare to these target sizes and relative Doppler shifts? What effect does the medium has and how do these systems adapt to clutter, interferers, and noise? This talk will focus on the underwater aspects of these systems which include (i) the properties of the underwater propagation medium, (ii) the geometry and material of the boundaries that limit the underwater propagation channel (this includes targets of interest and clutter), and (iii) the time-frequency and spatial properties of the underwater sources.
Discrimination of ripple spectra in a bottlenose dolphin in quiet and after noise exposure
Authors: Nechaev Dmitry , Popov Vladimir , Supin Alexander , Tarakanov Mikhail , Sysueva Evgeniya
Published: April 2019

The frequency resolving power (FRP) of hearing in quiet and after noise exposure was measured in a bottlenose dolphin using rippled-spectrum test stimuli and noninvasive recording of rhythmic evoked responses (the rate following response, RFR) to ripple phase reversals. Both the test signal and noise had band-limited spectra with the same central frequency; however, the noise had a non-rippled spectrum. The noise level was from -20 to 10 dB re test signal level. The baseline ripple density resolution depended on signal level and was the highest at levels from 80 to 100 dB re 1 μPa. At signal levels both above (up to 130 dB re 1 μPa) and below (down to 80 dB re 1 μPa) the optimal level, the ripple density resolution decreased. The impact of noise was different for different test signal levels. For low test signal levels (70 to 100 dB re 1 μPa), noise decreased RFR magnitude and resolution, whereas for high test signal levels (110 to 130 dB re 1μPa), low-level noise increased RFR magnitude and resolution. [Work supported by the Russian Science Foundation (Project 17-74-20107) awarded to E.V.S.]
Penguin vocalization classifications
Authors: Parshall Alexandra M. , Scheifele Peter M.
Published: April 2019

The present study researches five different penguin species vocalizations who currently residing at the Newport Aquarium in Newport, KY. These penguins—while different species—coexist in the same habitat at the Newport Aquarium. It was purposed that the different species do not “speak the same language” and therefore do not respond to different species of penguin’s calls, despite sharing the same enclosure. Therefore, this study aimed at collecting and categorizing the different species’ calls and then proceeding to analyze the vocal data to see if any of the species shared similar vocal spectrum similarities. Once collected, the aim of this data is twofold: primarily to classify the different penguin species calls—especially during specific events (i.e., defending a nest, distress, calling for a mate, etc.) and secondarily to analyze the vocal spectral energy of the different species to see if similarities exist.
Photoacoustic imaging in cancer medicine and research: Systems, results and future directions
Authors: Bamber Jeffrey C.
Published: April 2019

This paper reviews selected previous work in photoacoustic imaging conducted at the Institute of Cancer Research or with collaborators and considers directions for future research. For flexible introduction as an additional mode to clinical freehand ultrasound scanning, a multispectral epiphotoacoustic system was built by adapting a Zonare z.oneUltra™. Early clinical findings from photoacoustic imaging of breast tumours were consistent with contrast MRI although also provided evidence that photoacoustic image interpretation and penetration were limited by clutter generated by photoacoustic emissions from regions at or near the skin surface. Schemes for improving photoacoustic signal-to-clutter ratio were therefore explored. These have included deformation compensated averaging, spatial coherence processing, photoacoustic contrast agents, and localised vibration tagging (LOVIT). LOVIT (implemented using acoustic radiation force) was particularly successful, tripling penetration depth in breast-mimicking phantoms. It has also been implemented on a Verasonics™ platform and extended using a 3 + 3 interleaved comb-push method, which further reduces the clutter and improves the frame rate. Multidimensional and other extensions to LOVIT remain possible. Meanwhile, work at other institutions has explored various propagation model-based schemes. Most of the clutter reduction methods are complementary in nature, and a combined approach therefore represents a worthwhile direction for the future work.
Finite difference time domain ray-based modelling of acoustic scattering for target identification and tracking
Authors: Eastland Grant
Published: April 2019

The Finite Difference Time Domain (FDTD) method has provided a powerful technique for modelling and simulation of solutions of a variety of acoustics problems. The purpose of this investigation is to present work on the development of time-domain models of acoustic scattering from targets near a flat pressure-release boundary for use in identification and tracking from a moving receiving platform. The timing from the acoustic source to reception is dependent on the location dependent sound speed profile and the specular scattering points on the target. There can be multiple specular points revealed on the target because of interactions with the flat boundary, each can be modelled with the FDTD method and providing the correct path corrections using the same method to account for the variation in propagation path brought on by the sound speed profile of the propagating environment.
Temporally weighting a time varying noise field to improve Green function retrieval
Authors: Weaver Richard , Yoritomo John
Published: April 2019

We consider the retrieval of Green functions G from the correlations of non-stationary non-fully diffuse noise incident on an array of sensors. Multiple schemes are proposed for optimizing the time-varying weights with which correlations may be stacked. Using noise records created by direct numerical simulation of waves in a two-dimensional multiply scattering medium, cases are shown in which conventional stacking does a poor job and for which the proposed schemes substantially improve the recovered G, rendering it more causal and/or more symmetric, and more similar to the actual G. It is found that the schemes choose weights such that the effective noise field is close to fully diffuse, with little direction dependence to its intensity.
Case study on the use of Comsol Multiphysics for undergraduate aeroacoustic research
Authors: Jasinski Christopher
Published: April 2019

The aerodynamic drag imposed by acoustic liners for commercial aircraft is a growing area of research. With the next generation of aircraft being designed for quietness and fuel-efficiency, this is expected to be a continued hot topic for the foreseeable future. There is substantial motivation to use computational techniques to evaluate the acoustic liner system, but the finite element analysis tools necessary are often inaccessible to undergraduates. Many of the mechanical engineering students at the University of Hartford learn the basics of COMSOL Multiphysics simulation software through their coursework in fluid mechanics, and this study aims to leverage this skill into more advanced research. As part of a senior capstone project, a pair of University of Hartford undergraduates will be using COMSOL to determine the acoustic impedance for various liner types and assess methods of determining the skin friction coefficient of the liner. These results will be compared to experimental work conducted over the last few years at the University of Notre Dame and NASA Langley Research Center. Experimental results, including direct drag and more detailed flow measurements, will be presented along with the computational results from COMSOL and a reflection on the ease of use for undergraduate researchers.
Using measured data to enhance and extend vibro-acoustic performance predictions
Authors: Clot Arnau , Langley Robin S. , Meggitt Joshua , Hawes David , Elliott Andy S. , Moorhouse Andy
Published: April 2019

Modern industries usually need to ensure that their manufactured products meet certain vibro-acoustic requirements. Therefore, they have a clear need for models that can predict the broadband dynamic response of structural components at the design stage. The use of a hybrid deterministic-statistical formulation has been shown to be a suitable solution for predicting the response of a complex system in the mid-frequency range. This work explores two potential uses of experimental data to enhance and extend the applicability of the hybrid deterministic-statistical approach. Measured data are used to represent, first, complex vibration sources and, second, junctions between different structural components. The proposed uses are tested in a case study consisting of a deterministic source structure coupled to a statistical plate receiver. The approach is validated by comparing the predicted vibration response of the receiver plate to the one obtained by experimentally randomising the plate. The results show that a good agreement is obtained, both for the statistics of the receiver response and for the dynamic properties related to a point junction. It is concluded that the use of measured data can clearly extend the applicability hybrid models.
Perception of complex tones in noise
Authors: Hots Jan , Badel Gloria-Tabea , Verhey Jesko L.
Published: April 2019

We are often surrounded by technical sounds that contain tonal components, which usually are generated by rotating parts of machinery. Tonal components commonly reduce the pleasantness of a sound, i.e., these sounds are perceived as less pleasant compared to equal-level sounds without tonal components. To consider the influence of tonal components on noise pollution, different standards include sections dedicated to this effect. For single tonal components, previous data showed that tone adjustments calculated on the basis of the German standard 45681 account quite well for the reduced pleasantness. However, the standard is limited to single tonal components only. It was also shown that the partial loudness of the tonal portion corresponds to the perceived magnitude of tonal content (also known as tonalness or tonality). The present study investigated the perception of complex tones in noise. To this end, the loudness of the tonal portion of the sound is determined for sounds containing a single tone or a complex tone with two or four components at different levels above the masked threshold. It is shown that an increase in components results in an increase in the magnitude of the tonal content. This likely also affects the pleasantness of the sound.
Nonlinear response of a flanged fastened joint due to acoustical sine sweep excitation
Authors: Jerome Trevor W. , Shepherd Micah R. , Hambric Stephen
Published: April 2019

Fastened joints can significantly complicate the prediction of damping and resonance frequencies of built-up systems. This complexity often leads to over-designing for safety, which drives up manufacturing and operational costs. To improve understanding of the dynamic response of fastened joints, impact hammer and acoustically driven excitation of fastened plates at a flange have been measured. These findings add experimental data that are not well represented in the literature for such joints. The structure was excited acoustically, and acceleration was measured at multiple locations on the flange and plate. Backbone curves were generated with sinusoidal sweeps of acoustic input energy. These curves highlight the nonlinearity of the system, which varies according to fastener preload. Generally, as preload torque values decrease, nonlinearity increases with shifts observed in damping, stiffness, and resonance frequency. Data presented will be used to create a model for better predicting the global dynamic properties of built-up structures.