bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sea-ice parameters on acoustic propagation in different Arctic scenarios
Authors: Hope Gaute , Sagen Hanne , Hobæk Halvor
Published: October 2018

Depending on the setup and purpose of an acoustic propagation system (communication, navigation, tomography, seismic exploration) in ice covered areas, different parameters of the sea-ice are more significant in the interaction of acoustic waves with the ice. In homogeneous ice, with a source close to the surface, significant energy can be transferred to flexural waves and other ice-coupled modes. The modes in the ice are strongly dependent on the elastic parameters of the ice, as well as the thickness of the ice-plate. Additionally, discontinuities in the ice are very important to their propagation. In the inhomogeneous and fractured pack ice in the Arctic Ocean, where the cold water layer results in an acoustic surface channel, the majority of the acoustic waves will interact with the sea-ice at high incidence angles. Here, the roughness of the underside is more significant. Measurements from seismic experiments in an ice-covered fjord on Svalbard as well as long-range propagation in the ice-covered Fram Strait, together with simulations using OASES, are shown and used to gauge the effect of the different ice parameters. Although there is insufficient foundation for interpolation between the two extremes, the characteristics of the scenarios which determine the dominant ice-parameter are described.
Characteristics of the Arctic environment in the southern Beaufort Sea from Ice Exercise data
Authors: Joseph John E. , Reeder D. Benjamin , Olson Derek R.
Published: October 2018

In early March of 2016 and 2018, the Naval Postgraduate School participated in the biennial naval Ice Exercise (ICEX) conducted in the southern Beaufort Sea. Oceanographic and acoustic data sets collected near the ice camps during both events are compared. While the drift track of the ice camp during ICEX-18 was approximately one-degree south of the track in ICEX-16, there are important similarities in the oceanographic structure shown in both datasets. These characteristics have significant impacts on sound propagation in the region and may affect the performance of acoustic systems such as naval sonar and UUV navigation. Of particular interest are properties at the interface between the cold, fresh surface layer and the contrasting warm, saline Pacific Summer Water (PSW) that lays immediately below it. Sensors indicate turbulent mixing of high-spice and low-spice water occurs at this interface. PSW also sets up a stable subsurface sound channel with Pacific Winter Water and Atlantic Water layers below it. Strength of the sound channel varies from year to year; however, historical data from this region indicates an increasing trend. Other oceanographic features found in the upper 200 m of the under-ice water column in our 120-kHz echosounder dataset are discussed.
Assessment of safety zones for marine mammals at noise exposure from industrial activity in the Russian Arctic
Authors: Vedenev Alexander , Avilov Konstantin , Lunkov Andrey
Published: October 2018

E&P of hydrocarbon along with shipping are the main sources of manmade noise in the ocean. But very few information on the noise from industry activities in Arctic is currently available. Over the next decade we expect the increasing level of anthropogenic sound in the Russian Arctic due to planned large scale construction of Oil&Gas projects including the Shtokman project in the Barents Sea, one of the world's largest natural gas deposits. Noise from seismic surveying, pile driving and construction can damage hearing or disquiet marine mammals. To protect marine mammals from pulsed noise of seismic survey, pile driving and chronic continuous noise at different stages of the Shtokman project construction we estimated the sizes of safety zones with SPL thresholds of 180 dB (zone of injury) and 120 dB for continuous noise (behavior disturbance). Modeling of the transmission loss was done by Normal Mode and PDPE models based on the environmental characteristics in the Barents Sea and real spectra of noise sources—construction vessels and seismic airgun array. The results demonstrate changes in the Safety Zones footprints depending on the stage of construction, season, specific environmental conditions like ice cover interface or presence of gas saturated sedimentary layer.
Rapid prototyping for therapeutic ultrasound transducers
Authors: Hall Timothy L. , Maxwell Adam D.
Published: October 2018

Introduction: Piezoelectric materials are readily available from many suppliers at low cost. Finished ultrasound transducers, however, are significantly more expensive particularly for custom designs. Acoustics research often requires many iterations before a successful experiment design is achieved. This talk will present examples and what we’ve learned from ten years experience at the University of Michigan constructing transducers with rapid prototyping. Methods: Selective Laser Sintering, Stereolithography, and Fused Deposition Modeling techniques were all tested for transducer construction. Acoustic properties (sound speed, absorption, and impedance) were measured for various materials in each category. Ageing and degradation due to water ingress were assessed as well. Results: Housings for electrical/water isolation were successfully constructed using each technology. Professional quality machines yielded sufficient precision to create focused array structures up to 5 MHz. A majority of stereolithography materials showed very poor water compatibility degrading with exposure over time. Most materials have too low acoustic impedance for good matching layers. Particle filled stereolithography resins have increased density and sound speed that raise the impedance to more suitable values. Acoustic lenses were successfully constructed from stereolithography materials allowing focused transducers to be constructed from low cost flat piezoelectric materials.
High throughput system for preparing samples for genomic and epigenetic assays
Authors: Matula Thomas , Bomsztyk Karol , MacConaghy Brian , Maxwell Adam D.
Published: October 2018

Genomic and epigenomic therapies hold great promise for “fixing” faulty genes. In genomics, DNA is sequenced to determine the order of the nucleotides, while in epigenetics, immunoprecipitation of chromatin is used to locate specific proteins of interest. The first step for these therapies is to identify the specific sequence or gene responsible for the disease. To prepare samples for these assays, DNA or chromatin is sheared into fragments, most often using cavitation. However, standard tools such as ultrasonic horns can be highly inconsistent, leading to poor assays. In order to overcome the problems of inconsistent fragmentation, we designed and built a transducer array (free field pressures P +  = 30 MPa, P- = 12 MPa) capable of processing samples directly in 96-well microplates. An array of transducers is mounted below a microplate, coupled to a lens array that focuses acoustic energy into each well of a microplate. Intense cavitation is generated in each well. After treatment, gel electrophoresis shows that DNA and chromatin are fragmented to a range of sizes extending as low as 100 base pairs (34 nm). Importantly, this process results in consistent fragmentation that leads to consistent repeatable assays. [Funded by NIH R33CA191135, R21GM111439, R01DK103849 and Life Sciences Discovery Fund #12330479.]
Treatment monitoring for sonothrombolysis in deep vein thrombosis: Receiver array design
Authors: Acconcia Christopher , Jones Ryan M. , Hynynen Kullervo
Published: October 2018

The current treatment standard for deep vein thrombosis (DVT) is anticoagulation therapy, which does little to address long term morbidity compared to clot removal approaches. High intensity ultrasound can resolve clots by generating bubble clouds that erode thrombi. However, lack of appropriate treatment monitoring is a limiting factor in its widespread adoption. Passive cavitation imaging is capable of high frame rate, volumetric imaging, the combination of which has been shown to be important for monitoring the onset and development of bubble clouds inducing clot erosion (Acconcia et al. 2017). The results from our previous work motivated development of a device tailored to DVT with a relevant geometry (e.g., semi-cylindrical). Transmit simulations for such a device were conducted in a human thigh model (Smirnov and Hynynen 2017) with a design based on the modular transducer technology developed in our lab (Ellens et al. 2015). Here, we examine the integration of a sparse, randomly distributed receiver array within a semi-cylindrical arrangement of transmit modules for acoustic-based monitoring. Using a multi-layered propagation model, cavitation sources were localized to the femoral vessel, the accuracy of which depended on the inclusion of phase corrections. The receiver size was shown to be an important consideration with implicit trade-offs between directivity and channel SNR. Volumetric rates of ~1 MHz should be achievable with a modest number of receivers (128) in the presence of experimentally derived noise conditions.
Holographic characterization of therapeutic array transducers with assessment of measurement limitations and robustness
Authors: Kreider Wayne , Khokhlova Vera A. , Ghanem Mohamed A. , Sapozhnikov Oleg A.
Published: October 2018

Acoustic holography measurements and corresponding numerical projection methods have recently gained acceptance for characterizing the fields generated by high intensity therapeutic ultrasound (HITU) applications. To facilitate the standardization of such measurement-based simulation methods, it is important to understand how practical measurement challenges and limitations impact the results. Toward this end, holography measurements were acquired and analyzed for characterization of two therapeutic array transducers, each with 256 elements. For different focusing configurations, measurements comprised 2D holography scans as well as 1D scans used to independently quantify the focal lobe. The fields projected from holograms were compared to independent 1D scans to evaluate the impacts of hydrophone directivity, non-orthogonality of the axes of the positioner used to move the hydrophone, and overall mechanical stability of measurements. Results demonstrate that directivity effects exceeded those expected based on hydrophone size and altered focal pressures on the order of 10%. Non-orthogonality of the positioner shifted apparent focal locations by measurable distances, which could be confused with small shifts in device fixturing. However, holographic reconstruction of the ultrasound field structure near the focal lobe was robust with respect to directivity and non-orthogonality, which enables compensation by relative calibration of source output levels. [Funding support by NIH R01-EB025187, R01-EB007643, and P01-DK043881.]
Comparison of acoustic quality according to the types of flat panel display: Direct drive with exciter speaker
Authors: Park Hyung Woo , Lee SungTae , Park Kwanho , bae Myungjin
Published: October 2018

With the technological improvements in the display industry, display panel manufacturers have changed the picture quality from simple high definition to augmented reality or virtual reality. In the previous research, the sound field implementation and sound quality improvement using organic light-emitting diode (OLED) flat panel was introduced. Recently, we have developed a technology for implementing sound in a drive even on a high-quality liquid crystal display. The LED panel has a multi-layer structure, and the backlight unit has a disadvantage of the wavelength transmission structure. In this study, we proposed a method to analyze LCD more effectively through previous studies. Also, we can play left channel and right channel like analysis 2 channel flat panel speakers with one panel. This flat panel speaker consists of direct drive actuator and diaphragm and is used as the outer glass layer of OLED and multilayer LCD. In the LCD panel, we configured the enclosure and adjusted the exciter for the output powers of the exciter were controlled to ensure. Furthermore, the vibration was transmitted to the last flat sheet. We also implemented a clear-sounding direct-drive exciter speaker flat panel display.
A study on the optimal speaker position for improving sound quality of flat panel display
Authors: Lee SungTae , Park Hyung Woo , Park Kwanho , bae myungjin
Published: October 2018

As a technological improvement in display industry, flat panel manufacturers have changed the screen quality from simple high definition to 5 sensation satisfaction. The sound quality is improved, which is the easiest way to enhance the senses satisfaction. The technology, which in a previous meeting in Minneapolis, is using an exciter speaker. That is, the vibrate panel itself is used to make and play the sound for multimedia information. In this study, the optimum position of the exciter was studied to improve the sound quality of the proposed multi–channel flat–panel speaker. We studied the pattern of the acoustic energy emitted by the exciter and the position and the radiation pattern of the speaker to prevent distortion of the sound when watching the display from a distance. The panel encloses the exciter and the back plane. We also studied the method of construction.
Active control of a highly directional primary source by compact novel secondary sources
Authors: Hu Qi , Tang Shiu-Keung
Published: October 2018

The active noise control in free space for a global attenuation is always very challenging, especially for extended and complex radiators. This work focuses on a finite simple line source possessing strong directivity of multi-lobe radiation pattern as the primary source, which is frequently encountered in traffic noise control problems modelling a busy road or the train noise. Conventional secondary sources of compact size radiate the sound wave omnidirectionally, resulting in tangible pressure level increase in off-axis areas. This paper introduces a novel constructed control source, which has reasonably directional sound radiation capability even with a very compact size in low-frequency. Comparing to common directive sources, such as axially oscillating baffled pistons, the novel sources can significantly improve the active control result in a global way.
Resolvent analysis for jet noise source identification
Authors: Pickering Ethan M. , Rigas Georgios , Schmidt Oliver T. , Colonius Tim
Published: October 2018

We use resolvent analysis and spectral proper orthogonal decomposition (SPOD) to deduce the acoustic sources for an isothermal Mach 1.5 round jet. Both physics-based resolvent analysis and data-driven SPOD (using a high-fidelity, experimentally-verified, large-eddy simulation (LES) database) provide a basis for predicting the perturbation field. Singular value decomposition of the resolvent operator based upon the LES baseflow provides optimal volumetric forcing modes, or sources, and their associated linear responses. To identify physically relevant resolvent modes, comparisons are made between the highest gain responses and the highest energy SPOD modes computed directly from LES realizations. The prevalence of the associated resolvent forcing modes in the data are then assessed by projecting them onto the full LES nonlinear terms. The resulting distributions are presented and a jet noise model leveraging these forcing statistics is discussed. [This research was supported by a grant from the Office of Naval Research (Grant No. N00014- 16-1-2445). Ethan Pickering was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.]
Fundamental study on the acoustic fields caused by the interference of supersonic jet with a perforated plate
Authors: Murata Yo , Iwasa Kazutoki , Ishii Tatsuya , Okamoto Koji , KANEKO SHIGEHIKO
Published: October 2018

The supersonic jet contains intensive sound sources. It is known that when this jet collides with the perforated plate, a complicated flow field is formed on the plate and a high-amplitude sound is radiated as compared with the case without the perforated plate. Attention is paid to understanding the sound generating mechanism and proposing the measures to alleviate the sound pressure levels. In this study, two types of fundamental model tests have been carried out with a simple combination of a nozzle and a perforated plate. One is acoustic measurement in an anechoic facility. Test results indicated the amplified sound pressure levels in the forward arc of the nozzle. The aperture geometry suggested certain suppression in sound pressure levels in the arc. The other test is an optical visualization with Schlieren photographs. The photographs tried to account for reflection of high-amplitude sound waves on the plate downstream the nozzle.
Acoustic/drag interaction and its impact on future aircraft design
Authors: Jasinski Christopher
Published: October 2018

For several decades, acoustic liner technology has substantially reduced the noise created by commercial jet engines. Conventional placement of the perforate-over-honeycomb liner is in the fore and aft bypass duct of an engine nacelle; however, future aircraft design may incorporate liners on additional surfaces, such as the underside of wings and the fuselage. In order to use liner technology in novel locations, the impact of the porous facesheet and core of the liner on the aerodynamic drag of the craft must be fully understood. Work conducted at the University of Notre Dame has experimentally evaluated this drag, as well as the impact of acoustic fields on the aerodynamic drag produced by acoustic liners. Measurements of several quantities across the full boundary layer profile show this impact is substantial and quantifiable. Such results for several liner facesheets will be presented. Through further testing of the acoustic impedance of various facesheets at the University of Hartford, the goal of striking design balance between acoustic performance and aerodynamic reliability can become more clear. Fluid mechanic, acoustic, and direct aerodynamic measurements for several liner samples will be presented and discussed.
Measurements of the farfield characteristics of an automotive ultrasonic sensor with a vertical temperature gradient
Authors: Kim Sang Hyun , Ohm Won-Suk , Choi Youngsoo
Published: October 2018

With the coming of autonomous vehicles on the horizon, a variety of sensor platforms such as ultrasonic, radar, lidar, and image sensors are currently under development. Among these, ultrasonic sensors play a key role in the autonomous parking system. An ultrasonic sensor emits and receives a sound pulse (usually centered around a few dozen kHz), and computes the distance to a nearby object assuming a constant sound speed. However, the assumption of constant sound speed is often invalid because of the meteorological conditions, and could cause errors in distance estimation. In this talk, we discuss the farfield characteristics of a typical automotive ultrasonic sensor in the presence of a vertical stratification of temperature hence sound speed. The sound speed profile on a hot summer day is derived from temperature measurements with a vertical thermocouple array, and the farfield acoustic pressure is measured using a 2-D array of microphones. The measurements indicate that refraction due to the stratification of sound speed can be significant enough to alter the farfield performance of an ultrasonic sensor, and thus should be taken into account in the design of the autonomous parking system.
Standing-wave and traveling-wave thermoacoustics in solid media
Authors: Hao Haitian , Scalo Carlo , Sen Mihir , Semperlotti Fabio
Published: October 2018

Thermoacoustics is a multi-physics process in which heat and mechanical power (associated with waves) can be converted into one other. This process has been exploited to design different types of modern-day energy conversion devices, such as thermoacoustic engines (TAE) and refrigerators (Swift, 1988), since the first experimental assessment of the phenomenon by Soundhauss (1850) in the glass blowing process. To date, all the thermoacoustic devices are fluid-based, using mostly air or Helium as the working medium. Our study explores for the first time the possibility of achieving thermoacoustic energy conversion in solid media, by laying out the fundamental theory and showing numerical evidence of the existence of both standing and traveling thermoacoustic waves in solids. Consistent with established results for fluid-based TAEs, the growth-rate-to-frequency ratio of traveling waves in solids is found to be significantly higher than that of standing waves. While sold-state thermoacoustics (SSTA) share some commonalities with their fluid counterpart, some important and noteworthy distinctions are present. For example, solids have the potential to be highly engineered (e.g., metamaterials), with their properties tuned to enhance thermoacoustic energy conversions. The theoretical investigation of this mechanism may motivate novel ideas designing a new generations of ultra-compact, highly efficient thermoacoustic devices.
Suspension optimization for a hermetic compressor assembled on a refrigerator
Authors: Pescador Sarda Alexandre A.
Published: October 2018

Noise annoyance generated by hermetic compressors is evaluated based on the sound power level (SPL) parameter measured in a reverberation room or using a semi-anechoic chamber. However, when the machine is assembled on a refrigerator, the SPL can be altered depending on the new system configuration and the way the machine is assembled in the final product. The vibration generated in the electrical machine is transmitted to the refrigerator resulting in noise at the surface. The aim of this study was to model the suspension of a compressor assembled in a flexible base and minimize the vibratory power flow transmitted to the base through an optimization process, taking into account parameters such as the spring position. Decreasing the power flow to the refrigerator base results in a reduction in the global levels of noise and vibration at the base plate.
Artificial Neural Network-DeltaEC Hybrid Model for Thermoacoustic Systems: New Synergistic Approach
Authors: Abdelrahman Anas M. , Zhang Xiaoqing
Published: October 2018

Despite the wide-spread use of DeltaEC model in thermoacoustics community, intrinsic nonlinear phenomena are still hindering its applicability to real practical situations due to assumptions and limitations. In the present study, artificial neural network (ANN) as an intelligent technique is hybridized with conventional DeltaEC model to provide a new synergistic approach called (ANN-DeltaEC) hybrid model for thermoacoustic research field. The aim of this paper is to improve the prediction accuracy of single DeltaEC model by integrating it with distributed and synergistic neural networks. One application for this new approach has been conducted on one standing wave thermoacoustic heat engine based on published literature work to predict the acoustic wave parameters, namely, oscillating frequency and acoustic pressure amplitude under given design considerations of stack geometry and resonator length. The results from hybrid synergistic model had been proven to be desirable in its accuracy compared to experimental work and better than the results of DeltaEC model itself. The present work had shown the capability of the new synergistic approach in accurately predicting the outputs for any new given inputs within given range. Further applied research will be devoted in order to identify complex mappings between thermoacoustic system parameters and their corresponding responses.
Does native language temporal experience transfer to audio-visual synchrony perception?
Authors: Behne Dawn , Wang Yue
Published: October 2018

The temporal alignment of what we hear and see is fundamental for the cognitive organization of information from our environment. Research indicates that a perceiver's experience influences sensitivity to audio-visual (AV) synchrony. We theorize that experience that enhances sensitivity to speech sound distinctions in the temporal domain would enhance sensitivity in AV synchrony perception. With this basis, a perceiver whose native language (L1) involves duration-based phonemic distinctions would be expected to be more sensitive to AV synchrony in speech than for an L1 which has less use of temporal cues. In the current study, simultaneity judgment data for the syllable /ba/ were collected with 23 steps of AV alignments: from audio preceding the video (audio-lead) to the audio and video being physically aligned (synchronous) to video preceding the audio (video-lead). Two groups of participants differing in L1 experience with phonemic duration were included: native speakers of Norwegian (binary phonemic quantity distinction) and English (no phonemic quantity distinction). Preliminary results based on measures the audio-lead threshold (ALT) support the hypothesis that native language experience may influence broad mechanisms of timing, such as those moderating AV synchrony perception. Findings contribute to understanding the underpinnings of experience and AV synchrony perception.
The role of social expectation in the perception of gay speech
Authors: Bouavichith Dominique A.
Published: October 2018

Previous sociophonetic studies have characterized lengthened /s/ as one of several acoustic correlates of gay(-sounding) speech (Linville 1998; Rogers et al. 2000). It has also been shown that listeners adjust their perceptual expectations when given social information about a speaker (Strand & Johnson 1996; Nidzielski 1999; McGowan 2015). There is evidence that /s/ duration serves as a cue in the perception of a speaker’s sexual orientation, but only when paired with another acoustic cue (Levon 2007). Can a social cue serve this role instead? Given these findings, how might the timecourse of lexical activation be affected as listeners are given social information about a speaker? The present investigation addresses these questions using eye tracking in a visual world paradigm to examine the effect of social expectation on the timecourse of lexical activation. Participants (N = 22) heard /CVs/ and /CVsC/ words with digitally lengthened /s/, in two test conditions. First, participants had no social information about the speaker; second, the speaker’s sexuality was given implicitly. Gaze patterns differed based on listeners’ experience levels with gay speech, with a higher latency to response for high-experience listeners. This suggests that social expectation varies as a function of listener experience with a sociolinguistic variety.
Retention of speech sound production and perception in young international adoptees
Authors: Broersma Mirjam , Zhou Wencui , Cutler Anne
Published: October 2018

While international adoptees commonly report not remembering their birth language, studies have shown that with re-exposure they learn to perceive birth-language sounds faster (Choi et al., PNAS, 2017; Pierce et al., PNAS, 2014, Singh et al., DevSci, 2011) and to pronounce them more accurately (Choi et al., RSOS, 2017) than non-adopted controls. We assessed birth-language memories in much younger adoptees than tested before, investigating whether memories were episodic or abstract in nature and which process—imitation or perception—survived longest. Participants were (Experiment 1) 21 Cantonese and (Experiment 2) 25 Mandarin adoptees in the Netherlands and 47 Dutch control children, aged 4-11. They were trained on perception of Cantonese/Mandarin affricate and tone contrasts, and tested on perception and production (imitation; recordings assessed by native-speaker identification and rating). For perception, adoptees initially performed similar to controls but outperformed them after training, similar to findings for adoptees tested as adults. For production, however, adoptees already outperformed controls from the pre-test, in contrast to previous results for adult adoptees. Thus, while international adoptees retain abstract memories of their birth language phonology which helps them in relearning the sounds later in life, imitation ability stands the test of time better than perception ability.
English listeners categorize murmured stops based on aspiration, not prevoicing
Authors: Cavasso Luca , Yeung Henny
Published: October 2018

Previous perceptual studies of English stop voicing focus on Voice-Onset Time (VOT). Aspiration is generally subsumed into VOT, yet [1] complicates this, evincing a trading relation between intensity of aspiration noise and VOT. Our study is the first to examine the role of VOT and aspiration in English listeners’ perception of non-native plain and murmured stops. We recorded Marathi talkers producing /CVsV/ nonce words beginning with /t/, /tʰ/, /d/, /dʰ/, e.g. /dʰaːsaː/, or their velar counterparts. The following acoustic measures were taken for each token: — Duration of prevoicing — After Closure Time (ACT) [2], i.e., the interval between release and periodicity — Pre-Vocalic Interval (PVI) [3], which includes ACT and the murmured portion of the vowel — Intensity of aspiration noise Canadian English listeners rated the stops on a 6-point scale from voiced to voiceless. Only results for murmured stops are discussed here. Despite variability of prevoicing duration in these tokens (range = 200ms, sd = 43), the factor did not correlate significantly with a token’s average rating (p>0.60). However, ACT (r=.53, p<0.001), PVI (r=0.39, p<0.001), and the mean intensity of aspiration noise (r = 0.58, p<0.02) did. Thus, aspiration, not prevoicing, best accounts for perceptual differences between murmured stops. [1] Repp, “Relative amplitude of aspiration noise…,” Lang. Speech 22, 1979; [2] Mikuteit & Reetz, “Caught in the ACT…,” Lang. Speech 50, 2007; [3] Berkson, “Capturing breathy voice…,” Kans. Work. Pap. Ling. 33, 2012.
Do low intelligibility voices induce false memories?
Authors: Chung Stephanie , Bishop Sophie , Babel Molly E.
Published: October 2018

Spoken language is highly variable with phonetic variation that is attributable to multiple dimensions, including, but not limited to, differences in dialect, mood, native language, sociolinguistic dimensions, and talker-specific idiosyncrasies. Phonetic variation has documented effects on other aspects of linguistic processing. For example, Sumner and Kataoka found that phonetic variation affected semantic processing in semantic priming and false memory tasks, to which they concluding that socially dispreferred (i.e., voices or accents that are socially stigmatized or less desirable) phonetic variation received less attention in encoding, leading to a lack of priming and higher false memory rates [Sumner & Kataoka, 2013, JASA-EL, 134(6)]. In this study we compare the intelligibility and propensity to induce false memories in a between-subjects design. Intelligibility is assessed as response latency in a speeded shadowing task, and false memories are measured using standardized false memory lists where reporting of critical lure items not in the auditorily presented list are counted as false memories. The speaker set consists of five speakers of English, representing two local accents, two nonnative accents, and one native nonlocal accent. The results of this study contribute to our understanding of how phonetic variation affects word recognition and semantic processing.
Acoustic-phonetic consequences of clear speech in Cantonese vowels and lexical tones
Authors: Cooper Angela , Bradlow Ann , Wang Yue
Published: October 2018

In adverse communicative contexts, speakers will modify their speech style to enhance intelligibility, which can involve a range of acoustic and articulatory adjustments. Prior work has focused on the influence of speaking style on spectral (e.g., vowel space expansion) and temporal distinctions (e.g., voice-onset time). Thus, this study investigated the extent to which such adjustments extend to the pitch dimension, namely lexical tone. Ten native Cantonese speakers were recorded producing five monosyllables with six Cantonese tones embedded in sentence contexts in both clear and conversational speaking styles. Acoustic analyses revealed that speakers produced two distinct styles, with longer vowel durations and greater vowel dispersion in clear relative to conversational speech. However, with regards to lexical tone production, the results indicated only a marginal re-adjustment of tones within the tone space as a result of clear speech. Specific contour tones, such as the low- and high-rising tones, saw increases in their F0 offset. However, mean F0, F0 range and tonal dispersion did not differ substantially between styles. These findings indicate that speakers maintain tonal stability across speaking styles, suggesting that, relative to segments, lexical tones may not be prioritized as phonological contrasts vital to enhance the overall intelligibility of the utterance.
Computer-vision analysis shows different facial movements for the production of different Mandarin tones
Authors: Garg Saurabh , Tang Lisa , Hamarneh Ghassan , Jongman Allard , Sereno Joan A. , Wang Yue
Published: October 2018

We aim to identify visual cues resulting from facial movements made during Mandarin tone production and examine how they are associated with each of the four tones. We use signal processing and computer vision techniques to analyze audio-video recordings of 21 native Mandarin speakers uttering the vowel /ɜ/ with each tone. Four facial interest points were automatically detected and tracked in the video frames: medial point of left-eyebrow, nose tip (proxy for head movement), and midpoints of the upper and lower lips. Spatiotemporal features were extracted from the positional profiles of each tracked point. These features included distance, velocity, and acceleration of local facial movements with respect to the resting face of each speaker. Analysis of variance and feature importance analysis based on random decision forest were performed to examine the significance of each feature for representing each tone and how well these features can individually and collectively characterize each tone. Preliminary results suggest alignments between articulatory movements and pitch trajectories, with downward or upward head and eyebrow movements following the dipping and rising tone trajectories, faster lip-closing toward the end of falling tone production, and minimal movements for the level tone.
The role of gender, ethnicity, and rurality in Mississippi back-vowel fronting
Authors: Herd Wendy , Cariño Joy , Hilliard Meredith , Coggins Emily , Sherman Jessica
Published: October 2018

While tense back-vowel fronting is primarily associated with young women throughout most of the United States, it has been documented in the speech of both men and women from a wide range of ages in the South (Fridland, 2001; Clopper, Pisoni, and de Jong, 2005). However, most of the work documenting back-vowel fronting has been limited to White speakers and has not explored social variation related to ethnicity with the exception of Fridland and Bartlett (2006) who found that both White and Black speakers in Memphis exhibited back-vowel fronting. The present study uses isolated productions of beat, boot, book, boat,and bought by 73 participants from Mississippito explore the role of gender, ethnicity, and rurality in back-vowel fronting. Gender and ethnicity—but not rurality—proved significant, and a significant gender by ethnicity interaction was found. These results indicate that White speakers from Mississippi front tense back vowels more than Black speakers and that White women are currently leading back-vowel fronting in this region. These results are consistent with previous findings that men participate in back-vowel fronting in the South, but they contradict Fridland and colleagues’ findings that men lead /u/-fronting and that Black speakers are participating back-vowel fronting.
The effects of second language proficiency on speech production in noise
Authors: Kawase Saya
Published: October 2018

Speech production is a dynamic process and talkers produce variance of speech in order to maximize intelligibility and minimize articulatory efforts (cf. hyper- and hypo-articulation model). Prior research has shown that native (L1) talkers modify their speech produced in noise, such as increasing intensity, and changing formant frequency (especially F1 for vowel production). However, it is still unknown to what extent L2 talkers accommodate the environmental need. For example, speaking in noise is less familiar for L2 talkers, especially English as foreign language (EFL) learners. In addition, EFL learners lack interaction in their L2 usage, i.e., their speech may not be successfully modified considering listeners’ facilitation. The current study thus tested this with Japanese EFL learners (high and low L2 proficiency). The target stimuli were English tense/lax vowel production (/i-ɪ/ and /u-ʊ/), which is known that Japanese learners of English tend to assimilate the spectral differences and instead use the durational contrast. Our preliminary results showed that both groups of the learners produced spectral enhancement of F1. However, only the high proficiency group used the temporal modification on /i/, potentially due to their faster speaking rate. These results suggest that different modification strategies were observed based on their L2 proficiency.
Implicit biases in monolingual and bilingual speech perception
Authors: Kutlu Ethan , Wayland Ratree
Published: October 2018

Accented speech shows a great deal of variation from the “native” norms that can lead to processing difficulty. Previous research on listeners’ performance on accented speech shows that the more varieties of accented speech the listeners are exposed to, the better their processing is (Baese-Berk, Bradlow, & Wright, 2013). Since many bilingualism studies suggest that bilinguals have advantages in allocating different resources such as attention during language processing (Costa, Hernández, & Sebastián-Gallés, 2008), there is a necessity to investigate bilingual listeners' processing of accented speech. In this pilot experiment, we will measure intelligibility and perceived degrees of accentedness of Tamil and British English presented in noise among American English monolinguals, and American English and Spanish Bilinguals. We will also perform different cognitive tests as well as an Implicit Association Test to see if prior implicit biases towards South Asian individuals affect the listeners’ intelligibility and accentedness rating scores. We hypothesize that bilinguals will be more accurate in the intelligibility task compared to monolinguals due to their exposure to more than one language. However, it remains to be seen whether this advantage will be equally realized in both varieties of English accented speech.
Mandarin learners' ESL fricatives
Authors: Lin Hua , Wu Junyu
Published: October 2018

Although English interdentals have been much studied in L2 acquisition, other English fricatives have not received comparable attention. The assumption is that the other fricatives, e.g., [s] which often have L1 counterparts do not pose a problem for ESL learners. However, it is now well understood that similarity between L1 and L2 counterparts may be more problematic in perpetuating an L2 accent. To gain insights into the issue, Mandarin speakers’ production of both ESL and native fricatives and their perception of the ESL fricatives is collected and analyzed. The results show that the lack of a problem is true for perception which shows ceiling performance. Production-wise, all ESL voiceless fricatives, not just [θ], are problematic for the Mandarin speakers, judged by a native speaker and measured acoustically on spectral moments and peak. Typically, these fricatives are not on target, but are produced more or less in the L1 fashion. A surprise finding is also made that an L1 counter part may not be the choice of a match; e.g., English [s] which has a close Mandarin counterpart is found replaced with [θ] or [ʃ] by some participants. The paper also discusses the production-perception relation over the findings on the fricatives.
Perception and production of syllable-tone homophones by second language learners of Chinese
Authors: Liu Jiang , Wiener Seth
Published: October 2018

This study examined how the relatively high degree of tonal homophony in spoken Mandarin affects learners’ perception and production of new syllable-tone words. Seventeen English-speaking-learners of L2 Chinese participated in a 3-day word-learning task in which pictures were paired with spoken syllable-tone words. Stimuli included 32 monosyllabic Chinese words (e.g., yu3 “feather”). 16 words corresponded to previously learned syllable-tone homophones (e.g., yu3 “language”); 16 words were previously unlearned combinations (e.g., yu4 “jade”). Learning was assessed on day 3 using a 4-alternative-forced-choice identification task and a picture-naming task. Twelve Chinese-L1 speakers identified the learners’ productions. Learners were overall more accurate at identifying words that had no previously learned homophone (94%) than words that lacked homophones (90%). The opposite trend was observed in production: learners were overall more accurate at producing words that corresponded to previously learned homophones (77%) than words that lacked homophones (72%). Mixed-effects logistic regression models revealed no statistical difference of the log odds of correct identification or production. These results indicate that despite encountering considerable tonal homophony in speech, learners did not gain advantage in perceiving or producing new words with homophones. The phonologically marked T2-T3 contrast was produced with the lowest accuracy relative to other tonal contrasts.
Gender normalization in fricative perception: Generational differences
Authors: Munson Benjamin , Logerquist Mara , Putman Melanie
Published: October 2018

Listeners identify fricatives ambiguous between /s/ and /ʃ/ differently depending on whether they believe that the talker is a woman or a man (Strand & Johnson, 1996; Munson, 2011; Winn, Rhone, Chatterjee, & Idsardi, 2013). Recently, Munson and Logerquist (2017, J. Acoust. Soc. Am. 141, 3982) examined the influence of imputed talker gender on fricative perception across four experimental conditions in a relatively large group (n = 99) of young adults. Surprisingly, Munson and Logerquist were unable to replicate the original finding, despite using stimuli that resembled those from earlier studies very closely. In the current study, we test the hypothesis that Munson and Logerquist's failure to find an effect of imputed gender was because of generational changes in the perception of gender in speech. We do this by comparing the performance of younger, college-aged listeners in Munson and Logerquist to the performance of a new cohort of listeners aged 33–48. Data collection for the latter cohort is ongoing. A finding that these listeners show effects of gender on fricative identification similar to those in previous studies will support the idea that Munson and Logerquist's failure to replicate this finding is due to generational changes in the perception of gender through speech.
Effect of native Korean dialects on Chinese learners' perception of lexical tones
Authors: Qin Zhen
Published: October 2018

Second-language learners (L2ers) weight cues (e.g., pitch) as a function of how the cues are used in the native language. This study investigates the effect of native dialect on the use of Chinese (i.e., Mandarin Chinese) tonal information by native speakers of Seoul Korean (SK) and Kyungsang Korean (KK). While SK does not use pitch to realize lexical prosody, KK uses pitch to realize lexically contrastive words. Intermediate-to-advanced SK-speaking or KK-speaking L2ers of Chinese (at the same Chinese proficiency) completed a forced-choice tone identification task and a speeded AX tone discrimination task. In the identification experiment, participants heard natural tonal stimuli carried by multiple syllables; in the discrimination experiment, the tonal stimuli were resynthesized to model on natural citation forms of two native speakers (one male, one female), and were superimposed on the vowel /y/. Data collection, with 15 SK listeners and 15 KK listeners to be tested, is ongoing in Shanghai. KK listeners are predicted to have a higher accuracy than SK listeners in identifying tones, and to weigh pitch contour more than SK listeners in MDS analyses of RTs when discriminating tones. If our hypothesis is correct, native dialect is suggested to be considered in L2 speech perception models.
Productive pitfalls in the phonetic pursuit of psycholinguistic questions
Authors: Redford Melissa , Kallay Jeffrey , Potratz Jill
Published: October 2018

Coarticulation in adult speech spans multiple segments, including across syllable and word boundaries. Little in the way of comparable data is available for child speech, where the focus has been on within-syllable anticipatory effects. Still, the developmental studies indicate that anticipatory coarticulation within a syllable is as strong in child speech as in adult speech, and perhaps stronger. This finding is consistent with the hypothesis that words are fundamental units of production under the long-held assumption that anticipatory coarticulation reflects speech motor planning. Our current work leverages this same assumption to investigate age-related changes in the structure of the speech plan. A related goal is to characterize the development of long-distance anticipatory coarticulation. For example, we are testing the hypothesis that younger children’s plan consists of more fully individuated word-sized production units than the plan guiding older children’s and adults’ speech in sentence elicitation experiments, where the initial boundary of a production unit is operationalized as the onset of lip rounding. The work has propelled us to develop a novel psycholinguistic measure of coarticulation, and is now leading us to question the concept of a speech plan and the nature of anticipatory coarticulation. [Work supported by NIH award number R01HD087452.]
Recalibration dominated by the right ear
Authors: Scott Mark
Published: October 2018

Recalibration is a phonetic learning process by which the perceptual boundaries between speech sounds are adjusted. In a typical recalibration experiment, ambiguous sounds are paired with videos that disambiguate the ambiguous sounds to one category or another, the perceiver learns the association and, when the video is absent, continues to perceive the ambiguous sounds as the learned categories. The current experiment tests whether recalibration is stronger in the right or left ear. The right ear has a direct link to the left hemisphere, where such perceptual learning likely occurs, and so we might expect the right ear to be more susceptible to recalibration. However, the right ear is less influenced by visual information so we might expect it to be less susceptible to such visual-based recalibration. In this experiment, participants heard an ambiguous speech sound (between /b/ and /d/) which was rendered unambiguous by accompanying video of a face pronouncing one of these sounds. In each block, the audio was presented exclusively to the left or right ear. After multiple exposures, participants’ perception of the ambiguous sound (without accompanying video) was tested. Data collection is ongoing, but currently there is a strong trend towards more recalibration in the right ear.