bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement and simulation of the sound field in a concrete grain silo
Authors: Helboe Daniela T.
Published: October 2018

This paper presents impulse response measurements of a concrete grain silo and results from simulations of the measured sound field. The purpose of the measurement and simulations has been to assess the validity of the evaluation tools used for the acoustic design of an art museum, a project comprising the renovation of an existing reinforced concrete grain silo building from 1935 into a space for exhibition of art. The architects' concept involves cutting the lower half of the silos to create a central space (approximate volume 6500 m3, height 28 m) and exhibition spaces (approximate volume 2600 m3, average height 12 m), while keeping the upper half of the cylinders with an open end to these spaces. This paper presents how the measurements and simulations of a single concrete grain silo (approximate volume 450 m3, height 30 m) were used to adjust relevant settings in the acoustic simulations. Uncertainties related to the simulation tools are presented and acoustical challenges imposed by the geometry of the proposed architectural concept are discussed.
Public lobby reverberation control using modelling software design
Authors: Buchan Ellen R. , Moquin Philippe
Published: October 2018

A public lobby with high ceilings and hard surfaces is often found to be an excessively reverberant space. Sound-absorbing finishes to ensure a good acoustic environment are required. This case study examines the acoustical analysis of the public lobby and adjacent corridors at the Edmonton Law Courts. Improving the acoustics of this workplace/public space is important to create comfortable working conditions, and minimize noise disturbances in the nearby courtrooms. Design parameters included reverberation time and sound pressure level (SPL). ODEON Auditorium software was used to determine the optimum sound-absorbent finishes required. An array of acoustical ceiling panels and wall panels were installed in the Lobby from this simulation. The results of acoustical measurements conducted after the acoustical renovation and the ODEON Modelling predictions are discussed and compared.
Sonar signal analysis: Biological consequences of out-of-band acoustic signals from active sonar systems
Authors: Lepper Paul A. , Risch Denise
Published: October 2018

Within the aquatic environment acoustic monitoring systems are widely used to monitor and assesses anthropogenic noise sources and potential impacts on many aquatic species. Passive acoustic studies are, however, often limited to acoustic observation of changes in the species vocalization. Changes in vocalizations such as vocal calls or use of echolocation signals can be interpreted as both presence/absence, i.e., the animals have moved away or a change in acoustic behaviours, for example, not vocalizing as before. Active sonar systems can offer an attractive alternative in behavioural response studies potentially providing high-resolution spatial and temporal tracking of non-vocalizing or currently “quite” species. The main frequency of the sonar signal chosen to be outside the hearing range of the species of interests. The potential, however, exists for signal generation away from the design frequency of the sonar based on both the transducer/electronics as well as the pulsed nature of the signal. These signals might be perceived by the species of interest and therefore alter the behavioural response under study. Typical active sonar signals are analysed and compared to known hearing and integration periods for a range of species and the potential biological consequences of this out-of-band energy evaluated.
Determining spectral properties of Bowhead whale vocalizations through automated methods
Authors: Caero Thomas V. , Thode Aaron , Verlinden Christopher M.
Published: October 2018

Determining spectral properties of whale vocalizations is valuable to the study of marine mammal behavior. However, manually measuring these properties is tedious, which motivates the search for automated methods. Linear regression and Radon transform methods were developed to automatically measure the slope of Bowhead whale frequency-modulated (FM) sweeps from spectrogram data. The Radon transform method was further expanded to include classification of whale vocalizations to aid in further analysis. The data collected using these methods were used to study the acoustic dispersive nature of marine mammal vocalizations in an ocean waveguide. Possible relationships were explored between the change in slope of the whale vocalization and range between each animal and the receiver.
Ray identification and ranging issues in deep water
Authors: Boyle John , Heaney Kevin D.
Published: October 2018

Ocean acoustic positioning systems require accurate measurements of travel time from several acoustic beacons. When receiver position is unknown, the uncertainties in the sound speed, source position, currents, internal waves, and tides must be addressed and bounded. High travel time accuracy has been achieved in the deep ocean in ocean acoustic tomography experiments via a combination of long-duration acoustic arrival time-series, accurate source/receiver positioning, and comprehensive, post-experiment ocean modeling and data assimilation. For offline autonomous underwater positioning, those are not available. Strategies to reduce acoustic forward model uncertainties and improve acoustic ranging in deep water will be discussed.
Effect of the wind-generated bubble layer on forward scattering from the ocean surface
Authors: Fan Yuzhe , Li Haisen , Xu Chao
Published: October 2018

Wave scattering from pressure release surfaces is a classical subject with a long history. The standard approach which treat the surface probabilistically has been well developed. Over the last decade, some problems are more effectively solved with the deterministic approach. However, the complexities of upper ocean affect acoustic scattering from the ocean surface, and wind-generated bubbles are one of the most important complexities. In this paper, the effect of wind-generated bubble layers on forward scattering from the ocean surface is studied. The extended Hall-Novarini model is used to describe the population spectral density of the bubble layer. The time-domain Helmholtz-Kirchhoff integral is used to describe the acoustic scattering from pressure release surfaces. The free-field Green’s function for an inhomogeneous medium is formulated using ray method. The advantages of such conjunction are as follows: (1) the geometric shadowing effects generally neglected in the H-K integral can be handled by ray method; (2) the Helmholtz-Kirchhoff integral can provide a correct solution even in caustics zones. The numerical simulation reveals that, for large wind speeds, the amplitude of scattering signal is negligible in contrast to the amplitude of direct path signal. In such situation, the reverberation will be dominated by volume scattering of wind-generated bubbles.
The arrival time of mode one in a stochastic ocean
Authors: Baggeroer Arthur B.
Published: October 2018

The travel time for end of the final finale is often used is in inversion algorithms for acoustic tomography experiments when there is impreciseness due to ship and mooring positions and/or motions. The rationale is the first mode has the maximum slowness and higher order ones must arrive earlier, so the finale must solely be composed of energy from the first mode. This places a constraint on the tomographic sections, e.g., on the summation of the ray path or mode group slownesses. In a two papers Dozier and Tappert (JASA, 1978) examined the re population of the mode space for signals propagating in a stochastic ocean described by a Garrett & Munk model for internal waves. In the limit of an energy conserving ocean, i.e. no loss through boundaries, the limit of the population goes to an equipartition population density which was verified by numerical experiments. For more realistic oceans with boundary losses, the limit is a race between loss and scattering. This complicates what can be well identified as mode one at long ranges at low SNR's. We perform a numerical experiment by spatial filtering for mode one along the range dependent path to select just its energy in the finale. Earlier NUMERICAL studies by the author, (JASA, 1998) suggests just five percent of the energy remained at one megameter ranges with a 1/2 Garrett/Munk ocean. [Work supported by ONR.]
Focusing ultrasound into the kidney using 3D patient models
Authors: Abbas Magda , Coussios Constantin , Cleveland Robin
Published: October 2018

The incidence of kidney cancer worldwide is on the rise particularly in older patients. The current gold standard of treatment is surgical resection, which has significant morbidity. HIFU is an attractive candidate for treatment of kidney tumours, as there is acoustic access and it has fewer risks then resection. However, clinical trials have had disappointing outcomes with intervening layers of fat identified as a significant obstacle. Here CTs from three patients treated in a clinical trial were segmented into different tissue types. Then acoustic simulations were undertaken using the k-Wave Matlab toolbox for a single element 0.95 MHz transducer as was used in clinical trials. Similar to previous reports we find that refraction due to fat layers results in fragmentation of the focal volume, in some but not all patients. The fragmentation was found to be sensitive to transducer placement. Therefore, a planning step was introduced where a virtual source was placed at the target location and then the predicted acoustic field outside the body was used to determine the best position for the transducer based on the received phase and amplitude. After optimal placement of the transducer there was up to 25% increase in the focal gain.
Analysis of a dual aperture approach and standing wave suppression pulse sequences for controlled transvertebral focused ultrasound delivery in ex vivo human thoracic vertebrae
Authors: Fletcher Stecia-Marie P. , O'Reilly Meaghan A.
Published: October 2018

Focused ultrasound (FUS), in conjunction with microbubbles (MB), can open the blood-brain barrier to aid therapeutic delivery. Its feasibility for blood-spinal cord barrier opening (BSCBO) has been demonstrated in small animals. Controlled transvertebral delivery of FUS to the human vertebral canal requires low frequencies to penetrate thick vertebral bone. The resulting focal depth of field (DoF) is comparable to the size of the canal, promoting the formation of standing waves (SW) and potentially compromising treatment safety. Through k-Wave simulations and experimental acoustic field scans, a confocal, dual aperture approach was investigated in combination with SW suppressing pulses (linear chirp, short bursts and random phase shift keying (PSK)) to simultaneously reduce DoF and mitigate SWs. Two transducers (470/530 kHz, angle 90°) reduced the DoF by 85% compared to a single transducer (500 kHz). While all modified pulses reduced SWs relative to a 30 cycle sinusoid, short bursts performed significantly better than longer burst methods such as linear chirps (p = 0.03, (59±15) vs (34±11)% reduction). In combination with PSK, short bursts implemented in the dual aperture configuration mitigated SWs, while producing a uniform focal spot. The feasibility of using confocal, dual-aperture FUS to create a controlled focus within ex vivo vertebrae has been demonstrated. Next steps will include investigating MB emissions under short burst, PSK exposures, and characterizing spectral content associated with BSCBO and tissue damage.
Passive elastography monitoring of a high intensity ultrasound treatment: A study of feasibility in in vitro liver
Authors: Giammarinaro Bruno , Barre`re Victor , Melodelima David , Catheline Stefan
Published: October 2018

High intensity focused ultrasound (HIFU) is a non-invasive modality of intervention allowing thermal ablation in soft tissues by locally increasing temperature. Thermal lesions can be observed as a change in tissue elasticity properties, and so in shear wave velocity, by elastography. Most of studies based on ultrasound imaging used shear waves created by acoustic radiation force. Some of these studies presented elasticity measurements during a treatment in tissues like livers. They demonstrated that the elasticity increases during the treatment and so that the lesion becomes progressively harder than the original tissue. Acoustic radiation force method still presents some difficulties to obtain elasticity in deep tissues. However, in the human body, a natural noise due to cardiac activity or arterial pulsatility can be used to characterize the elasticity in using noise correlation techniques, it corresponds to passive elastography. This method depends on the imaging technique and so can image deep tissues. The objective is so to study the feasibility of using passive elastography technique during a treatment. Here, experiments are performed in in vitro porcine and bovine livers, heated with an acoustic transducer till 80°C and imaged with a high framerate ultrasound imaging device.
Stress reduction effects using deep breathing rhythm pattern based on speech utterance system
Authors: Bae Seonggeon , bae myungjin
Published: October 2018

A breathing with a certain pattern plays an important role in heart breathing, and it is very important for daily life by relieving physical tension and finding psychological stability. In order to verify this, we analyzed the phonetically evoked organs and studied the appropriate method. In the general study, a reliable effect of 83% was confirmed in 200 experimental groups. In the future, we will perform many studies from the viewpoint of speech signal processing using these features.
A study on voice enhancement using palm reflections
Authors: Park Hyung Woo , bae Myungjin
Published: October 2018

Peoples communicates with others using voice that is essayist way. Voice is a means of conveying your opinions or thoughts. In complex social life, voices become rough and tone changes due to various causes such as condition, stress, singing, effect of drugs and changing the pitch due to changes in the numerical value of hormones. This will result in the other party not being able to communicate. In order to solve this treatment from the hospital. In this paper, we introduce the phenomenon of improving the clarity of human voice by utilizing the reflected sound waves of the palm. In previous research, We proposed the methods that using voice recorded or a solid surface mug. In this study, we propose method that peoples own voice reflected from the palm of their vocal organ. Speak the voice for “ah,” “e,” “o”, “ooo” for a minute and make a sound wave in each mouth and massage it. The reflected voice from the palm stimulates delicate massage of the skin cells of the mouth, further enhancing the original voice enhancement function.
Using Navier-Stokes modeling to design a better recorder
Authors: Thacker Jared W. , Giordano N.
Published: October 2018

We use the Navier-Stokes equations to model how air flows in the mouthpiece region of the recorder. Different geometrical designs for this region are investigated, and the effect of these modifications on the tonal properties are studied. We find that simple changes from the standard mouthpiece geometry can have large effects on the resulting spectra which we have traced to changes in the vortex patterns near the labium. Our modeling results have been tested by using 3D printing to make instruments suggested to be most promising. The modeling results also reveal how subtle changes in features like the sharpness of the labium can have a profound effect on the behavior. [Work supported by NSF grant PHY1513273.]
Direct aeroacoustic simulation of acoustic radiation in recorders with different windway geometries
Authors: Onogi Kimie , Yokoyama Hiroshi , Iida Akiyoshi , Shoji Tetsuro
Published: October 2018

To clarify the effects of the windway geometry on the aeroacoustic feedback in the jet fluctuations in recorders, direct aeroacoustic simulations were performed along with experiments. The simulations were based on the compressible Navier-Stokes equations to predict the fluid-acoustic interactions. The volume penalization method was used to reproduce the flow and acoustic fields around the complex shape of the recorders. Two recorders with straight and arch-shaped windway were explored. The occurrence of mode change was observed at the higher velocity for an arch-shaped windway model compared with the straight windway model. The modified formulation of the negative displacement model (N.H.Fletcher et al., 1976, J. Acoust.) was proposed based on the predicted jet fluctuations, where the jet fluctuations were divided into hydrodynamic and acoustic components. The ratio of the hydrodynamic component to the acoustic component near the windway exit was lower in the arch-shaped windway model than that in the straight windway model, whereas the amplification factor of the jet fluctuations was larger in the arch-shaped windway model. The relevance of these results and the mode change along the jet velocity is to be discussed.
Derivation of network-wide surface condition corrections for rail noise modelling
Authors: Croft Briony , Balding Tasia , Everton Pascal , Stein Jasen
Published: October 2018

Noise modelling and mapping techniques are increasingly being used to understand noise impacts to communities across large geographic areas. Rail transit noise around a network can vary considerably with factors such as track type, train speed, rail roughness/surface condition, among others. Reference source levels for a particular rolling stock type are normally derived by measurement at a particular location or locations, and applied around the network. When modelling noise network wide, it is important to understand how variable rail roughness can affect predicted noise levels at locations other than those used for measurements. With elevated guideway, it can also be difficult to access appropriate external measurement locations. This study describes a study undertaken for the Vancouver SkyTrain network using the Nord2000 rail noise prediction algorithm. Variations in rolling noise level of the order of 15 dB were identified and attributed to rail surface condition. Noise measurements inside a test train were used to determine frequency dependent train speed coefficients and corrections to apply for rail condition around the network. This paper describes the approach used and the outcomes in relation to this city-wide rail noise mapping project.
Soundscape approach integrating noise mapping in Namsan Promenade
Authors: Yoo Jisu , Ki Kyong Seok , Ryu Hunjae , Kim Ji Suk , Chang Seo I.
Published: October 2018

Namsan is a 262 m high mountain located in the center of Seoul. Its easy accessibility and tourist attractions such as a cable car and a tall tower on the top allure native and foreign people. It functions as a park rather than a mountain and has a 7.5 km promenade around it with a moderate slope where even the old and the weak enjoy walking. Some parts of the promenade are surrounded by trees and flowing waters but other parts are influenced by shuttle buses, roundabout road-traffic and various machines etc. Noise maps for the sources were generated to find the spatial distribution of the noise over the mountain including the promenade. By observation along the promenade, natural sound including mainly birdsong and water streaming sound were identified and sound maps were generated. To collect individual responses from 4 acousticians and 6 non-acoustic people about an on-site questionnaire of the sound environment along the promenade, a total of 37 spots were selected apart from each other by approximately 200 m. The responses were used to generate soundscape maps. Separate and combined analyses of the three acoustic maps were performed to propose some measures to improve sound quality of the promenade.
Sound grade classification with sound mapping of national park trails in South Korea
Authors: Ryu Hunjae , Ki Kyong Seok , Yoo Jisu , Chang Seo I. , Kim Bo-Hyun
Published: October 2018

Most of the national parks in South Korea are exposed to noise pollution caused by urban noise from adjacent cities. Especially, the road-traffic noise from the roads passing through or surrounding the parks has increased the exposure. In addition, the military and tele-communication facilities located in ecologically sensitive highlands are noise sources and affect nearby ecosystems. Therefore, it is important to preserve and maintain a comfortable sound environment to ensure the quality of the park trails for visitors and the habitat of animals and plants. The purpose of this study is to map a sound environment of national parks in South Korea and to classify sound grades of park trails. The park trails were categorized into 5 different groups based on acoustic factors such as noise level, loudness, sharpness, roughness, and tonality, and environmental factors such as land-use, ground coverage, vegetation type, and relative location which can be obtained from biotope map and GIS DB. This classification was based on factor analysis and cluster analysis. It is expected that this sound grade classification of the national park trails meets the right of visitors to know the sound environment, and that the managers of national parks can use it as a guideline to create a positive sound environment.
Strongly focused vortex beams by using flat Fresnel-spiral lenses
Authors: Jiménez Noé , Romero-Garcìa Vicente , García-Raffi Lluis M. , Camarena Francisco , Staliunas Kestutis
Published: October 2018

We report geometrically-optimal diffraction gratings for sharp vortex beam focusing using Fresnel-spiral curves. The lenses are built based on the Fresnel-spiral, a spiral curve that combine the focusing properties of Fresnel zone plates and the phase dislocations produced by spiral gratings. On the one hand, the constructive and destructive interferences between open and opaque zones in the grating, in analogy to the Fresnel zone plate, allow sharp beam focusing. On the other hand, the spiral shape of the grating retains the helicity, rotating the phase of the diffracted waves and creating a phase dislocation along the axis. This allows the generation of geometrically optimal focused vortex beams, enhancing the field intensity at the focus up to 170 times. In particular, this system offers a tunable topological charge of the vortex beam by using different arms in the Fresnel-spiral diffraction grating, being the topological charge equal to the number of arms. Two different Fresnel-spiral diffraction gratings with topological charge of 1 and 5 are experimentally tested showing excellent agreement with theory and simulations. These diffraction gratings will allow the design of effective wave-matter interaction systems, with direct applications in industry and biomedical engineering.
Bessel beam superposition for analyzing off-axial scattering, forces, and torques
Authors: Zhang Likun
Published: October 2018

Illumination of an arbitrary-order Bessel beam on an off-axial object is expanded as illuminations of a series of Bessel beam components of different orders on an axially centered object [L. Zhang, J. Acoust. Soc. Am. 143(5), 2796–2800 (2018)]. The expansion follows from a parallel-axis relation that is derived as a generization of Graf's addition theorem of Bessel functions. The off-axial Bessel beam expansion enables to understand the off-axial scattering, forces, and torques in terms of superposing that in the on-axial illuminations by the series of beam components. The superposition reveal negative axial radiation force and negative radiation torque in terms of contributions of different beam components in the on-axial configuration. The exact locations of the object for torque direction reversal are analytically identified for a small particle. The superposition also reveals that the off-axial radiation torque on a small particle exists even for higher-order vortex beams or vortices.
Three-dimensional acoustical radiation forces in the view of momentum conservation
Authors: Zhang Likun
Published: October 2018

Analysis of acoustic radiation forces is essential for tailoring parameters for desired manipulations or for interpreting special force conditions. Previous theoretical derivation for acoustic radiation forces was from integration of stress tensor of the total fields. Given that the force is a second-order effect, interactions between the incident and scattered fields or between different beams contribute to the forces and complicate the analysis. Here the three-dimensional forces exerted by an arbitrary field is presented in the framework of momentum conservation where force superposition is possible for flexible analysis. The force is related to momentum transfers by ingoing and outgoing spherical waves and to momentum transfers associated with extinction and scattering. Superposition of forces based on orthogonality of momentum and insight into force dependence on beam and scattering parameters for special manipulations are addressed.
Insights from individual differences: Uncovering the code for frequency modulation
Authors: Whiteford Kelly L. , Kreft Heather A. , Oxenham Andrew J.
Published: October 2018

Perceiving changes in frequency (frequency modulation; FM) and amplitude (amplitude modulation; AM) are essential for human and animal communication. Our goal was to utilize individual differences in sensitivity for FM and AM to better understand how FM is represented in the auditory system. Previous studies suggest that FM of low-frequency carriers (fcs < ~4 kHz) at slow modulation rates (fm < 10 Hz) is coded by precise, phase-locked spike times in the auditory nerve (time code). The same fcs at faster rates may utilize a tonotopic (place) code, whereby FM is converted to AM through cochlear filtering. We measured FM and AM detection for a low fc at slow (fm = 1 Hz) and fast (fm = 20 Hz) rates across three large groups: Young, normal-hearing (NH) listeners (n = 100), NH listeners varying in age (n = 85), and listeners varying in degree of sensorineural hearing loss (SNHL; n = 49). Results from all groups show high multicollinearity amongst FM and AM tasks. Data from SNHL but not NH listeners show strong correlations between the fidelity of cochlear place coding (frequency selectivity) and FM detection at both rates. Overall, the evidence suggests a unitary place code for FM. [Work supported by NIH Grant No. R01 DC005216.]
Tinnitus related to physiological changes in the auditory nerve in chronically noise-exposed mice
Authors: Screven Laurel A. , Burke Kali , Lauer Amanda , Xu-Friedman Matthew A. , Dent Micheal L.
Published: October 2018

Tinnitus is a pervasive auditory dysfunction affecting up to 10% of the adult population. The perception of ringing or hissing in the absence of a physical stimulus in one or both ears can be caused by acoustic trauma and other factors. Mice are a commonly used model for auditory disorders in humans, although the behavioral examination of tinnitus in mice has primarily been limited to reflexive measures involving inhibition of the acoustic startle by gaps in noise. Using an identification paradigm, we behaviorally tested whether mice show symptoms of tinnitus following long-term moderate noise exposure. Tinnitus was demonstrated by a shift in categorizing silence as narrowband noise. This experiment demonstrated that tinnitus can be induced in mice using noise exposure, similar to that caused by salicylate. Physiological and anatomical experiments reveal synaptic changes including response facilitation, increased reliability, increased synaptic terminal area, and increased number of release sites in mice housed in chronic background noise compared to standard-housed controls. These mice show normal auditory brainstem responses and a normal complement of peripheral auditory nerve synapses. This combination of behavioral and physiological methodologies enables researchers to examine both the behavioral manifestations and the underlying physiological mechanisms of tinnitus.
Relations between speech perception in noise, high-frequency audiometry, and physiological measures of cochlear synaptopathy
Authors: Guest Hannah , Munro Kevin , Plack Christopher J.
Published: October 2018

Cochlear synaptopathy, a loss of synapses between inner hair cells and auditory nerve fibers, is associated with age and noise exposure in animal models. However, the functional consequences of synaptopathy for humans are unclear. We pooled data from two recent studies to answer the question: are the common physiological measures of cochlear synaptopathy related to speech-perception-in-noise (SPiN) performance? Eighty-three audiometrically normal participants (ages 18–39) took part. Measures of synaptopathy were as follows: auditory brainstem response (ABR) wave I amplitude (102 dB peSPL click); ABR wave I:V amplitude ratio; envelope following response (EFR) amplitude (4 kHz carrier, 105 Hz modulation frequency); EFR amplitude growth with stimulus modulation depth; and middle ear muscle reflex threshold (1–4 kHz elicitors). We also conducted extended high-frequency (EHF) audiometry (10 and 14 kHz), suggested as a marker for synaptopathy in lower frequency regions. SPiN performance was assessed using the coordinate response measure with spatial maskers. None of the physiological measures of synaptopathy correlated significantly with SPiN. There was a significant correlation between EHF thresholds and SPiN, although it is unclear whether this is due to a direct relation between EHF hearing and SPiN, or whether elevated EHF thresholds are a marker for hidden damage at lower frequencies.
Olivocochlear system plasticity in response to chronic noise
Authors: Villavisanis Dillan F. , Schrode Katrina M. , Javaid Hamad A. , Muniak Michael , Odedoyin Omobolade , Gellatly Victoria , Xu-Friedman Matthew A. , Lauer Amanda
Published: October 2018

Plasticity in the medial and lateral olivocochlear (MOC and LOC) systems in response to chronic exposure to background noise was investigated. Three different age-groups of young mice were exposed to the same chronic moderate noise conditions with either immediate tissue harvest or harvest following restoration to quiet conditions, with age matched controls. Cochleae were dissected and standard immunohistochemistry protocols were used to label hair cells with antibodies against myosin 6 and olivocochlear synaptic terminals with synaptic vesicle protein 2 (SV2). Specimens were imaged using confocal microscopy, and density of SV2 labeling was quantified. There was no statistically significant difference in MOC SV2 density between mice raised in noise and age matched controls for any group. However, there was a statistically significant increase in LOC SV2 density for adult mice raised in noise, particularly at higher frequency regions. This could suggest a protective upregulation of the efferent system against chronic moderate noise exposure. The increase in LOC innervation persisted for juvenile mice raised in noise with subsequent restoration to quiet conditions. These data suggest that the LOC system demonstrates sound-dependent plasticity, but that synaptic morphology may be altered for a substantial time period after exposure to noise ceases.
Reliability and interrelations of seven proxy measures of cochlear synaptopathy
Authors: Plack Christopher J. , Guest Hannah , Munro Kevin
Published: October 2018

Investigations of cochlear synaptopathy in living humans rely on proxy measures of auditory nerve function. Numerous procedures have been developed, typically based on the auditory brainstem response (ABR), envelope-following response (EFR), or middle-ear muscle reflex (MEMR). Some metrics correlate with synaptic survival in animal models, but translation between species is not straightforward; measurements in humans likely reflect greater error and greater variability from non-synaptopathic sources. The present study assessed the reliability of seven measures, as well as testing for correlations between them. Thirty-one normally hearing young women underwent repeated measurements of ABR wave I amplitude, ABR wave I growth with level, ABR wave V latency shift in noise, EFR amplitude, EFR growth with stimulus modulation depth, MEMR threshold, and an MEMR difference measure. Intraclass correlation coefficients indicated good-to-excellent reliability for the raw ABR and EFR amplitudes, and for both MEMR measures. The ABR and EFR difference measures exhibited poor-to-moderate reliability. No significant correlations, nor any consistent trends, were observed between measures, providing no indication that the between-subject variability in responses are due to the same underlying physiological processes. Findings suggest that proxy measures of cochlear synaptopathy should be regarded with caution, at least when employed in young, normally hearing adults.
Intervocalic consonant voicing vs. lengthening in two Athabaskan languages
Authors: Hargus Sharon L.
Published: October 2018

For over a century, various authors have described intervocalic consonants in Athabaskan languages as being long (e.g., Sapir 1914 on Chasta Costa, Cook 2004 on Dene Sųɬiné (Chipewyan), McDonough and Ladefoged 1993 on Navajo). Such descriptions, even if instrumental, have generally not been very detailed, and have not adequately investigated the factors which may influence lengthening, such as stress and position in word. In this presentation, I first present results of an investigation of effects of position and stress on the duration of consonants with internal cues to duration (fricatives and consonantal sonorants) in two Athabaskan languages, Deg Xinag and Kwadacha Tsek'ene. Results show that intervocalic consonants are longer before stressed than unstressed syllables. Next, I present results of an instrumental study of [t] which shows that a competing and antagonistic process to intervocalic lengthening, intervocalic voicing, is also found in both languages. Intervocalic stops are voiced through approximately 80% of their closure duration before unstressed vowels in both languages. Intervocalic voicing of stops has been reported for Tahltan (Bob 1997) and Dene Sųɬiné (McDonough and Wood 2008) but generally not for other Athabaskan languages except for those in which nasals have evolved into voiced obstruents (e.g., Jicarilla Apache, Tuttle 2000).
The rhythm of Hul’q’umi’num’
Authors: Marshall Mackenzie , Bird Sonya
Published: October 2018

This research explored the linguistic rhythm of Hul’q’umi’num’, a dialect of the Coast Salish Hul’q’umi’num’-Halq'eméylem-həəmiə language, and initiated phonetic documentation of it. Rhythm was analyzed from an audio file of an Elder telling a story. The story was segmented and phonetically transcribed using acoustic analysis software (Praat), and rhythm was measured based on the segmentation. Rhythm metrics demonstrated that consonantal intervals of Hul’q’umi’num’ patterned like no other documented language (according to ΔC and VarcoC). In terms of vocalic intervals (%V, ΔV, and VarcoV), Hul’q’umi’num’ patterned in the same rhythmic category as English (“stress-timed”). Interestingly, several differences emerged between the segmentation-based phonetic transcription and the transcription provided by language experts, such as consonant cluster elisions, loss of glottal stops, and vowel alternations. Further investigation of their systematicity and effects on Hul’q’umi’num’ rhythm as a whole is needed to understand what components of the language give it its unique rhythm.
Acoustic properties of singleton and geminate ejective stops in Tsova-Tush
Authors: Hauk Bryn G.
Published: October 2018

Tsova-Tush, also known as Batsbi, is an underdescribed Northeast Caucasian language spoken by a few hundred people in Zemo Alvani, Georgia. The Tsova-Tush phoneme inventory includes four geminate stops that contrast with singletons at the same place of articulation: /tʰː t'ː qʰː q'ː/. The existence of geminate ejective stops is particularly interesting, as such phonemes are cross-linguistically rare, having been reported in only 13 of the 2,155 phoneme inventories sampled by PHOIBLE (http://phoible.org/). The present study characterizes these stops in Tsova-Tush based on high-quality audio recordings of four Tsova-Tush speakers producing a list of 65 target words in a carrier sentence. The following measures were statistically compared: closure duration, VOT, duration of the preceding vowel, and f0 and H1*-H2* in the following vowel. Preliminary results from three speakers suggest that ejectives are characterized by shorter VOT, a shorter preceding vowel, and a difference in both f0 and H1*-H2* in the following vowel, with marked interspeaker variation in the latter measures. This study provides the first detailed description of this typologically interesting two-by-two contrast (singleton aspirates, geminate aspirates, singleton ejectives, geminate ejectives) at two places of articulation (dental and uvular) in an underdescribed language.
An acoustic and articulatory investigation of the Mauritian vowel inventory
Authors: Myers Samantha , Henri Fabiola , Berkson Kelly
Published: October 2018

While there have been a decent amount of morphosyntactic and sociolinguistic studies on Mauritian, a “French-based” creole spoken by most of the population of Mauritius (e.g. Baker 1972, Alleesaib 2012, Henri 2010, Miller 2015, Syea 2013), phonetic or phonological description on the language hardly exists. Pudaruth (1993) proposes a phoneme inventory consisting of 19 consonants and 8 vowels, intuitively noting that rhotics preceding vowels are weakened, almost unpronounced. In the present work, we empirically investigate the vowel inventory of Mauritian using acoustic and articulatory data. In addition to presenting basic acoustic measures (e.g. vowel spaces), we investigate the rhotic and report acoustic measures which suggest strong variation between the orthographic “a” that precedes “r” and that which precedes all other written consonants. Ultrasound imaging confirms that the pre-rhotic “a” differs from other “a”s articulatorily.
Variation in Scottish Gaelic preaspirated stops: Across speech styles and in connected speech
Authors: Klein Maya
Published: October 2018

This paper examines variation in preaspiration in Scottish Gaelic, an endangered language spoken in Scotland. Previous studies (Clayton 2011; Nance & Stuart-Smith 2013) have examined Gaelic preaspiration in careful speech. The present study investigates whether 1. Preaspiration patterns similarly in casual speech as previously attested in careful speech and 2. If variation in preaspiration resembles processes of stop reduction, or sound change in progress. Preaspiration is examined in casual speech across speakers, and across different speech styles within one speaker. Preaspiration is measured for duration, as well as band-pass filtered zero crossing rates, developed by Gordeeva & Scobbie (2010) and adapted for Scottish Gaelic by Nance & Stuart-Smith (2013). Results confirm that variation in preaspiration pattern similarly to previous studies: preaspiration is longer and has higher change in zero crossings for /k/ and in words with a preceding short vowel. This study contributes to the existing literature in that it shows that preaspiration is shortest in words that are phrase medially. This study shows that preaspirated stops are not heavily reduced, and that variation in preaspiration patterns like an ongoing sound change. This study highlights the importance of carefully investigating variation in typologically rare phenomena in endangered languages.
F0 of the verbal nasal prefix in Medumba
Authors: Liu Yadong
Published: October 2018

Both tone-bearing unit (TBU) and non-TBU syllables can exist in a tonal language [Roberts 2003, Cahiers voltaïques/Gur Papers 6, 95]. The verbal nasal prefix bears a high tone in many Bamileke languages [Voorhoeve 1974, Stud. Afr. Ling. 5: 205]; in Medumba, however, anecdotal evidence suggests that the nasal prefix may be a non-TBU [Keupdjio 2018, PC] in which case it cannot bear a high tone. The present study investigates the F0 contour of the verbal N-prefix and its surrounding TBUs (e.g., vowels in the preceding auxiliary verb and the following main verb) in various contexts in Medumba. Acoustic results show that the F0 contour of the nasal prefix itself is largely determined by the F0 trend of the preceding vowel, and no F0 change is observed at the onset of the nasal prefix, confirming that the verbal N-prefix is a non-TBU in Medumba. However, the nasal prefix appears to induce a raised F0 at the onset of the following TBU, indicating that, although the N-prefix itself does not express tone, it nevertheless “bears” a high tone. Implications for theories of TBUs will be discussed.
Comparative analysis of South Korean and North Korean vowels: A pilot study
Authors: Lee Jungah , Idemaru Kaori , Vaughn Charlotte
Published: October 2018

This study investigates cardinal vowels of standard North Korean and South Korean. Prior reports have suggested that North and South Korean vowels have undergone changes after decades of relative isolation. This poster reports a pilot study investigating the ways in which the language standards of North and South Korea are similar and different by examining the speech of newscasters from each country. Acoustic analysis of the speech data suggested that North Korean vowels [ɛ] and [æ] were produced in the higher position relative to the South Korean counterparts, and the back vowels [ʌ] and [o] showed overlapping formant values unlike the South Korean counterparts. The perception experiment suggested that South Korean listeners could not accurately identify the North Korean [ʌ] and [o]. These results indicate that there may be interesting differences across North Korean and South Korean vowels.
On the non-universality of intonation: Evidence from Triqui
Authors: DiCanio Christian , Hatcher Richard
Published: October 2018

Languages with large lexical tone inventories typically involve less freedom for suprasegmental properties to be manipulated for pragmatic meaning or phrasal constituency (Connell 2017). However, such languages may still use F0 to a limited degree for marking information structure or utterance finality (DiCanio et al. 2018, Xu 1999). We present results from three field experiments with 11 speakers where we investigated information structure and prosody in Itunyoso Triqui, an Otomanguean language (Mexico). Itunyoso Triqui possesses nine lexical tones (/4, 3, 2, 1, 43, 32, 31, 13, 45/), fixed final stress, and contrastive phonation type. In experiment 1, we examined tone production in words in broad and narrow focus contexts. Words under narrow focus were lengthened slightly (13-14%) but no general effect of focus on F0 levels or contours was found. In experiment 2, we examined tones in utterance non-final and final contexts. Words were lengthened in utterance-final position relative to non-final position, but no F0 differences were found. In experiment 3, we investigated F0 declination in sentences consisting of only level tones and found no F0 change across utterances. The results from these experiments suggest that Itunyoso Triqui does not use F0 to encode information structure or prosodic boundaries.
The Suzhou Chinese “apical” and “fricative” vowels: Uniformity and idiosyncrasy
Authors: Faytak Matthew
Published: October 2018

“Fricative” and “apical” vowels have been variously described as syllabic voiced fricatives, syllabic approximants, or high vowels, often based on impression. To better characterize their articulatory and acoustic nature, ultrasound video and acoustic data on the production of the “fricative” and “apical” vowels were collected from 43 speakers of Suzhou Chinese, along with the vowels [i, y, æ, u] and the fricatives [s, ɕ]. Analysis reveals substantial interspeaker variation, largely idiosyncratic, which may contribute to the range of descriptions given to “fricative” and “apical” vowels. This variation, however, obscures the fact that the “fricative” vowels are curiously uniform in tongue posture with the alveolopalatal fricatives for most speakers. The “apical” vowels are consistently produced with a tongue posture similar to the alveolar fricatives and affricates, such as [s], that they obligatorily follow. The “fricative” vowels, on the other hand, are phonotactically freer, and speakers exhibit a wider range of articulatory strategies. Individuals’ favored articulations can be situated on a continuum between lamino-postalveolar, or [ɕ]-like, and dorso-postalveolar, akin to an advanced [i]; most speakers favor the lamino-postalveolar strategy. Acoustic analysis suggests that speakers also vary in whether they favor production of fricative noise during both the “fricative” and “apical” vowels.
Review of directional sensors for low frequency underwater acoustic applications
Authors: McConnell James A. , Rorick Timothy P.
Published: October 2018

In this review, we present some of the more common embodiments directional sensors take on for use in low-frequency underwater acoustic applications. Sensors that fit within this paradigm are typically substantially smaller than an acoustic wavelength and can form first- or second-order cardioid beams at frequencies well below 10 kHz. A mathematical treatment of scalar, vector, and dyadic acoustic fields is presented as it pertains to understanding the phenomenology the sensors are required to measure. Cardioid beam-forming and directivity index are explained to provide context of using directional sensors in aperture constrained situations. The electro-acoustic performance of various sensor concepts is presented using lumped parameter models. Packaging concepts for high-fidelity operation, low self-noise, and low electronic noise in the seawater environment are shown. Special problems such as using directional sensors in deep water or near impedance boundaries is also covered.
Inferring low-frequency compressional sound speed and attenuation in muddy sediments from long-range broadband sound propagation
Authors: Wan Lin , Badiey Mohsen , Knobles David P. , Wilson Preston S.
Published: October 2018

While researchers have successfully applied many geo-acoustic inversion methods, involving normal mode analysis or matched field processing, to invert seabed parameters in sandy bottoms, inferring low-frequency compressional sound speed and attenuation in mud is still a challenging problem, especially for a marine sediment where a mud layer overlies a sandy bottom. Recent studies show that there is an ambiguity between the low-frequency attenuation of mud and sand in three different inversion algorithms based on (1) modal amplitude, (2) transmission loss, and (3) spatial coherence measurements [JASA 143, 1798 (2018)]. An increase (decrease) of mud attenuation can be compensated by decreasing (increasing) the attenuation in the sandy basement. In this paper, an inversion method combining these three inversion algorithms and statistical inference techniques (e.g., Bayesian-Maximum Entropy, [JASA 138, 3563–3575 (2015)]) is utilized to analyze the long-range broadband acoustic signals measured by several vertical and horizontal line arrays during the Seabed Characterization Experiment 2017 conducted in the New England Mud Patch. Reliable estimates of the low-frequency mud properties are obtained by removing the ambiguity. Finally, the inverted results are compared with historical experimental data and theoretical predictions. [Work supported by ONR Ocean Acoustics.]