bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of co-occurrence restriction on perception of laryngeal contrast in Seoul Korean and East Kyungsang Korean
Authors: Hwang Hyun Kyung
Published: November 2016

This study investigates dialect differences between Standard Korean and East Kyungsang Korean with respect to the role of co-occurrence restriction on perception of laryngeal contrast in stops and fricatives. The results obtained from the identification test first confirm that the laryngeal contrast is present only in the stops, but not in the fricatives in East Kyungsang Korean. In order to further explore the role of laryngeal co-occurrence restriction in the two varieties of Korean, identification tests using nonce compounds were conducted. The results provide experimental evidence of the laryngeal co-occurrence restriction; Both Seoul and East Kyungsang speakers’s perception of laryngeal contrast in stop consonants is conditioned by laryngeal specification of the preceding consonant. With respect to the perception of laryngeal contrast in fricatives, however, only Seoul Korean speakers exhibit the effect of the co-occurrence restriction. These results lead to the conclusion that the co-occurrence restriction plays a crucial role in the perception of laryngeal contrast both in stops and fricatives in Seoul Korean, while the laryngeal features are phonologically irrelevant for fricatives in East Kyungsang Korean. 
Perception of place of articulation of assimilated nasal and oral stops: What do response times and eye fixations tell us?
Authors: Mohaghegh Mercedeh , Chambers Craig
Published: November 2016

Two forced-choice identification and two visual world eyetracking experiments examined perception of the place of articulation (PoA) of word-final nasal and oral stops either in canonical (coronal) or assimilated form (coronal-to-labial place assimilation, e.g., ‘phonem /batp button’). Listeners’ response times (RT) and eye fixations were measured as they heard and, using a screen-based paradigm, identified assimilated or unassimilated words presented auditorily either in isolation (excised from recorded sentences) or with the assimilation-triggering context present (next word began with a labial consonant). Listeners were slower to identify isolated words ending in nasals, especially when words were assimilated. When the triggering context was present, RTs were overall faster and no longer different between nasal and oral stops. The eye fixation data further showed an early sensitivity to PoA cues carried by vowel transitions for assimilated oral stops. For words ending in assimilated nasal stops, however, fixation patterns only showed sensitivity to the PoA cues at a later point where the assimilation-triggering context was heard. These findings indicate a distinction in terms of perceptual uptake of acoustic cues between nasal and oral stops. The results also suggest the precise mechanisms involved in compensation for assimilation may vary across sound classes (nasal vs. oral stops).
Perceptual adaptation to nonnative speech by school-aged children
Authors: Bent Tessa , Frye Julianne
Published: November 2016

With training, listeners can improve their understanding of speech in adverse listening conditions, including those stemming from the environment (e.g., competing noise) and the talker (e.g., unfamiliar accents). For example, listeners can increase their ability to understand a specific nonnative talker and, when trained with multiple talkers with the same nonnative accent, can generalize their learning to novel talkers with that accent. The current study extends these findings by investigating children’s perceptual adaptation to nonnative speech. School-aged children can retune specific speech sound category boundaries, but little is known about their abilities to adapt to naturally produced nonnative speech. To assess children’s adaptation to nonnative speech, 6- and 9-year-old children were presented with sentences produced by multiple Mandarin-accented talkers and repeated what they heard (training condition) or were not given training (control condition). A posttest assessed their understanding of sentences produced by a novel Mandarin-accented talker. Performance on the posttest was more accurate for children in the training condition than those in the control condition, which may have resulted from task learning or perceptual adaptation. In addition to phonetic category retuning, the results suggest that children may be able to improve their decoding of nonnative speech.
Understanding the relationship between acoustics and articulation of nasal and oral vowels
Authors: Barlaz Marissa , Johnson Sarah , Shosted Ryan , Carignan Christopher , Fu Maojing , Liang Zhi-Pei , Sutton Brad
Published: November 2016

While real-time magnetic resonance imaging (rt-MRI) provides high spatiotemporal resolution for speech research, the associated audio is noisy, presenting a challenge for research on the relationship between articulation and the acoustic signal and solving the articulatory inversion problem. Using state-of-the-art denoising methods, the current study denoised rt-MRI audio associated with nasal and oral French vowels produced by one speaker, and extracted F1-3 from the midpoints of each vowel for /a, o, e/ and their nasal counterparts. Oblique images were taken of the velopharyngeal port at 25 frames/second, and average pixel intensity (API) in the velopharyngeal region was taken from images corresponding to the vowel midpoint. General additive models showed a significant relationship between API and F1 for oral and nasal vowels. (Lower API indicates a wider velopharyngeal opening.) F1 of /ã/ was lower than /a/, while F1 was higher in the nasal /õ/ and /ẽ/ than their oral counterparts, all of which are expected effects of naso-pharyngeal coupling. These results show that the acoustic recordings produced during rt-MR imaging can be used to explore the relationship between articulation and acoustics, and can give insight into the articulatory effects of nasality, something difficult to understand through acoustics alone.
Investigating patterns of vowel production using real-time magnetic resonance imaging
Authors: Proctor Michael I.
Published: November 2016

Characteristic tongue postures of 21,478 vowels produced by four speakers of General American English were compared in lexically stressed and unstressed positions to examine patterns of articulation and reduction. Image frames capturing midsagittal vocal tract configurations were reconstructed at the acoustic midpoint of each vowel produced in a 3,450 word forced-aligned transcribed speech corpus (Narayanan et al. 2014). Sixty image sets were constructed, consisting of all exemplars of each contrastive vowel quality of American English, as produced by each speaker: up to 1049 tokens of the most frequent vowel /i/, and 48 tokens of the least frequent vowel /ɔɪ/. Image frames were cropped to a region of interest centred on the tongue dorsum, and linearized into one-dimensional vectors in which pixel intensity corresponds to presence of soft tissue. Principle components analysis was applied to each set of image vectors to examine the distribution and variability of tongue tissue associated with each vowel posture. “Eigentongues” were constructed from the most significant components in each image set (Sirovich & Kirby 1987; Hueber et al. 2007), resulting in a set of images characterizing each speakers’ vowel space, produced in both lexically stressed and unstressed positions.
Physiological features of geminate depending on the speaking rate
Authors: Sakakibara Ken-Ichi , Yamakawa Kimiko , Imagawa Hiroshi , Goto Takao , Yamauchi Akihito , Maki Katsuhiro , Amano Shigeaki
Published: November 2016

In this study, we examined the physiological and acoustic characteristics of plosive- and fricative-type geminates, three each of minimal pairs for the plosive- and fricative-type geminates were recorded in different speaking rates, with there ranges are from 3 to 13 mora /s. Physiological analysis showed that (1) an opened duration of vocal folds depends on a speaking rate; (2) a closing duration of vocal folds depends on a speaking rate but an opening duration does not. Acoustical analysis showed that, when a speaking rate increases, (1) logarithm of closure and fricative durations linearly decrease; and (2) a ratio of the duration of a singleton to a geminate decreases.
Post-focus compression: All or nothing?
Authors: Huang Ting , Hsieh Feng-fan
Published: November 2016

Post-focus compression (PFC) has been claimed to be a “hard-to-evolve,” inherent prosodic feature that may have a single historical origin (Proto-Nostratic). This study explored the distribution of PFC in two sub-dialects of Malaysian Hokkien (Southern Min Chinese), i.e., Penang Hokkien (PH) and Melaka Hokkien (MH), using novel experimental designs and statistical techniques (SS ANOVA). Specifically, in addition to the conventional nasal onset-only contexts, stop and fricative onset-only contexts were taken into consideration. We analyzed F0 and duration of the constituents in question under three focus conditions (Initial vs. Medial vs. Final focus in the Subject-Verb-Object frame). The results are (a) the presence of PFC may be dependent on different segmental contexts: in MH, PFC is attested in the stop onset-only environments but absent elsewhere and (b) the absence of PFC “induces” Post-focus shortening in the nasal and fricative-only contexts in MH and in all data in PH. The findings suggest that PFC may not be an “inherent” feature because MH and PH are closely related sub-dialects and both have had language contact with the same language, Malay. Finally, global F0 raising is found for the first time in Final focus (Object) in both MH and PH.
Just noticeable differences for pitch height and pitch contour for Chinese and American listeners
Authors: Jongman Allard , Qin Zhen , Zhang Jie , Sereno Joan
Published: November 2016

Previous studies suggest that Chinese listeners may be more sensitive to pitch direction while American listeners primarily attend to pitch height. The present study sought to establish JNDs for pitch discrimination using a three-interval, forced-choice procedure with a two-down, one-up staircase design (cf. Liu, JASA 2013). We manipulated a high rising and a high falling Mandarin tone produced by a female speaker. Specifically, for pitch height, a standard contour rising from 200 Hz at tone onset to 230 Hz at tone offset was paired with deviants that were parallel to the standard but started (and ended) at lower and higher f0 values (onsets ranging from 185 to 215 Hz in 1 Hz steps). Likewise, a standard contour falling from 200 Hz at tone onset to 170 Hz at tone offset was paired with parallel deviants whose onsets ranged from 215 to 185 Hz. For pitch direction, standard rising and falling contours were paired with deviants with either steeper or shallower slopes, again varying in 1 Hz steps. Results indicate that, overall, Chinese listeners are more sensitive to pitch direction and American listeners to pitch height. However, these effects are modulated by both the direction (falling/rising) and steepness of the contours.
Spatial congruence in multimodal speech perception
Authors: Keough Megan , Schellenberg Murray , Gick Bryan
Published: November 2016

A growing literature provides evidence for the importance of synchronicity of cross-modal information in speech perception [e.g., audio-visual, Munhall et al. 1996, Perception & Psychophysics 58: 351-362; audio-aerotactile, Gick et al. 2010, JASA 128: 342-346; visual-aerotactile, Bicevskis et al. submitted ms]. While considerable work has investigated this role of temporal congruence, no research has directly explored the role of spatial congruence (i.e., co-directionality) of stimulus sources. If perceivers are picking up a localized distal speech event [e.g., Fowler 1986, Status Report of Speech Research: 139-169] cross-modal sources of information are predicted to be more likely to integrate when presented codirectionally than contradirectionally. An audio-aerotactile pairing lends itself well to this question as both modalities can easily be presented laterally. The current study draws on methodology from previous work [Gick & Derrick 2009, Nature 462: 502-504] to ask whether cross-modal integration persists when cross-modal cues are spatially incongruent. Native English perceivers were presented with syllables contrasting in aspiration and embedded in noise, with some tokens accompanied by inaudible air puffs applied to the neck; aerotactile source locations either matched or opposed the spatial direction of the acoustic signal. Implications of results for multimodal integration theories will be discussed. [Funded by NIH Grant DC-02717 and NSERC.]
Plasticity of the internal model for speech sounds: Articulatory changes during intensive visual biofeedback treatment
Authors: Vick Jennell C. , Mental Rebecca L. , Carey Holle , Schreiber Nolan T. , Barnes Andrew , Lee Gregory S.
Published: November 2016

Visual biofeedback, commonly delivered by a display of ultrasound of tongue position, has demonstrated effectiveness for treating residual speech errors in older children and adults. It can be challenging to make kinematic measures during treatment without the use of a head stabilizing system, however, and it is likewise not possible to measure the changes in speech motor control that accompany improvements in speech sound production. Opti-Speech, a visual biofeedback treatment software that uses EMA to provide positional data, has the benefit of providing a steady stream of position data throughout baseline and treatment sessions. In this study, Opti-Speech treatment was provided with an intensive schedule (2x/day for 5 days) to two adolescent males with persistent speech errors (i.e., lateralized /s/). Marked improvements in /s/ accuracy and quality were noted over the course of treatment and are reported in another paper (Mental et al., this meeting). Kinematic measures were made of tongue position throughout the course of the three baseline and 10 treatment sessions, including peak velocity, duration, and measures of token-to-token variability. The covariance of changes in these measures with increasing accuracy and quality of /s/ productions will be reported.
Historical, current, and legal bases for forensic speaker identification
Authors: Yonovitz Al , Joe Herbert , Yonovitz Joshua
Published: November 2016

It is of great interest to the legal system to identify individuals by their voice. Controversy in this area has continued for nearly seven decades with states divided with regard to the merits and standards used for forensic voice identification. Forensic speaker identification and admissibility of expert testimony has always been questionable, and is meeting more legal and scientific criticism. A number of methodologies have evolved that provide different approaches to speaker identification. These methods will be contrasted with a systematic review. In addition, the legal qualifications to testify as an expert witness in state or Federal courts—regardless of specialty, including in civil or criminal cases have evolved since the landmark 1923 Frye case, as well as the more sweeping 1993 Daubert case, and continue to evolve. This presentation discusses the history of the qualifications, an overview of different jurisdictional requirements, and the legal requirements of a speaker identification voice expert. The enigma of speaker identification for use in forensic applications will be illustrated by utilizing actual cases applying various methods of speaker identification or elimination.
Digital acoustic communications through solids
Authors: Scarton Henry A. , Saulnier Gary , Wilt Kyle , Cunningham Michael
Published: November 2016

Digital acoustic communication solid channels make it possible to send data through metallic barriers with up to very high rates while also transferring power and with lower complexity, lower size and power. This paper presents different techniques for achieving this including data transfer rates up to sever kilobits per second (kbps) using simple switching technique to many megabits per second through thick steel. Modulation techniques include Chirp-On-Off Keying (C-O-OK) to Orthogonal Frequency Division Multiplexing (OFDM) and even Multiple-Input Multiple -Output (MIMO) approaching 700 Mbps. Frequencies up to 4 MHz are used with piezoelectric elements propagating longitudinal waves or transversely polarized shear waves serving as the sending and receiver sensors.
Wave physics of the frequency difference autoproduct: Bilinear time-frequency analysis
Authors: Worthmann Brian M. , Dowling David R.
Published: November 2016

Frequency difference beamforming (Abadi et al., 2012, JASA, 132, 3018-3029) and matched field processing (Worthmann et al., 2015, JASA, 138, 3549-3562) are array signal processing techniques that determine acoustic ray-path directions and source locations, respectively, from sparse array recordings by shifting the signal processing to a lower, out-of-band, difference-frequency bandwidth. This frequency down-shift is accomplished through the use of the frequency difference autoproduct (Δf-AP), a quadratic product of complex frequency-domain acoustic field amplitudes at two different frequencies. In this presentation, the physical and mathematical underpinnings of this quadratic product are discussed. Specifically, in the branch of applied mathematics termed bilinear time-frequency analysis, this Δf-AP is actually one of four quadratic time-frequency functions, each inter-related through forward and inverse Fourier transforms. The other three functions are the time-domain autoproduct, the Wigner distribution, and the ambiguity function. These four functions and several of their interesting properties are reviewed, including their relationship to the Wiener-Khintchine Theorem, and the spatial and spectral coherence and correlation functions. Additionally, the behavior of these functions when evaluated from simulated acoustic recordings from ideal single-path and multi-path acoustic environments is shown and compared. [Sponsored by ONR and NSF.]
The investigation of the method for measuring the low-frequency radiated sound power in a reverberation tank
Authors: Zhang Yi-ming , Tang Rui , Li Qi , Shang Da-jing
Published: November 2016

In order to measure the low-frequency radiated sound power of the underwater sound source in a reverberation tank, the measuring method based on the characteristic acquisition of the testing sound field is proposed. Based on the normal-mode theory, the spatial averaging properties of the reverberation sound field with the ideal boundaries is firstly derived, of which the sound field transfer relationship from the reverberation field to the free field is obtained. In addition, for the purpose of obtaining the characteristic of the testing sound field with the general boundaries, the numerical method based on the ACTRAN software is utilized. According to obtaining the characteristic of the testing sound field in advance, the low-frequency radiated sound power can be got by measuring the square pressure in a reverberation tank. The proposed method is checked by the experiment measurement. The test results show that by utilizing the proposed method, the low-frequency radiated sound power of the underwater sound source has been accurately measured in the glass tank below the Schroeder cut-off frequency, of which the radiated sound power level deviation is less than 2 dB compared with the free field.
A comparison between direct measurements and inference results from an acoustic propagation experiment in Currituck Sound
Authors: Ballard Megan S. , Sagers Jason D. , Lee Kevin M. , McNeese Andrew R. , Wilson Preston S. , Muir Thomas G. , Costley R. D.
Published: November 2016

An acoustic propagation experiment was conducted in Currituck Sound to characterize low frequency propagation in a very shallow-water environment with water depths of only a few meters. Signals from a Combustive Sound Source (CSS) were recorded on bottom mounted geophones and a vertical array of hydrophones. The CSS produces a broadband signal with significant low frequency energy, and the analysis presented in this paper focuses on frequencies below 2.5 kHz. A statistical inference method was applied to obtain an estimate of the sediment sound-speed profile as a function of depth in the seabed. During the experiment, in situ measurements of compressional and shear wave speed and attenuation were also collected 30 cm below the sediment-water interface. Bimorph bender elements were employed to generate and receive horizontally polarized shear waves in the frequency range from 200 Hz to 1 kHz. Compressional waves were measured using cylindrically shaped piezoelectric elements operated in the 5 kHz to 100 kHz frequency band. Sediment acoustics models were fit to the in situ wave speed and attenuation measurements to enable comparison with the inferred low frequency sound speeds. [Work supported by ERDC, ARL:UT, and ONR.]
Numerical study of three-dimensional sound reflection from corrugated surface
Authors: Choo Youngmin , Song Heechun , Seong Woojae
Published: November 2016

When a sound wave propagates in a water medium bounded by a smooth surface wave, reflection from a wave crest can lead to focusing and result in rapid variation of the received waveform as the surface wave moves [J. Acoust. Soc. Am. 125, 66-72 (2009)]. In prior work, propagation paths have been constrained to be in a plane parallel to the direction of corrugated surface waves, i.e., a two-dimensional (2-D) propagation problem. In this paper, the azimuthal dependence of sound propagation as a three-dimensional (3-D) problem is investigated using an efficient, time-domain Helmholtz-Kirchhoff integral formulation. When the source and receiver are in the plane orthogonal to the surface wave direction, the surface wave curvature vanishes in conventional 2-D treatments and the flat surface simply moves up and down, resulting in minimal temporal variation of the reflected signal intensity. On the other hand, the 3-D propagation analysis reveals that a focusing phenomenon occurs in the reflected signal due to the surface wave curvature formed along the orthogonal plane, i.e., out-of-plane scattering.
Toward a test of the existence of the Biot slow wave in sand using layer resonances
Authors: Bonomo Anthony L. , Venegas Gabriel R. , Isakson Marcia J. , Wilson Preston S.
Published: November 2016

Geoacoustic models based on Biot's theory of poroelasticity have found some success in predicting the interaction of underwater sound with sandy sediments. One of the unique features of Biot theory is its prediction that poroelastic media can support two types of compressional waves—the conventional compressional wave, referred to as the “fast wave,” and an additional, slower compressional wave due to the out-of-phase motion of the saturating fluid with respect to the solid frame dubbed the “slow wave.” While Biot-based sand models have been shown to accurately fit measured compressional sound speed and attenuation data, shear wave sound speed and attenuation data, bottom loss data, and backscattering strength data, the so-called slow wave has not been directly measured in sand. Rather than attempt to directly measure the slow wave, it is the goal of this work to confirm or disprove the slow wave's existence from the resonances it causes in thin sand layers. It is expected that these resonances would be apparent in measurements of normal-incidence bottom loss. Finite element models are used to demonstrate the possible effectiveness of this approach. Experimental design and preliminary measurements are also considered. [Work supported by ONR, Ocean Acoustics.]
Room acoustic measurement techniques for large venues (greater than 10,000 cubic meters) in 2016
Authors: Duty Jason R. , Decker Jeremy L. , Holst Peter K.
Published: November 2016

From sine sweeps to maximum-length sequence (MLS) type signals, balloon explosions to the yachting cannon, options to measure room acoustics in large venues have increased over the past couple of decades. There are new developments by academia and equipment manufacturers, as well as improvements on older methods. What are these new methods? What acoustical characteristics can one measure with each method? This presentation describes the different source options to measure room acoustical characteristics in larger spaces.
Subjective acoustical quality in healthcare office facilities
Authors: Hodgson Murray
Published: November 2016

Health-care facilities include many non-clinical office spaces for administrative staff; the role of acoustics in these spaces has been underexplored. This paper discusses the acoustical part of a study of indoor environmental quality (IEQ) in 17 healthcare office facilities. A subjective survey assessed office worker perceptions of their environments in general, and satisfaction with the acoustics. Self-reported productivity, well-being, and health outcomes were also captured. Satisfaction was lower with acoustics than with other aspects of IEQ. Satisfaction results were related to room type (e.g., open plan vs. shared vs. private office) and the absence or presence of a sound-masking system. Acoustics was the most important aspect of IEQ in predicting occupant satisfaction and well-being. Regression models were developed to predict workplace satisfaction, well-being, and job satisfaction from survey responses. Results of physical acoustical measurements showed very low correlations with subjective responses. The knowledge gained from this study informs the decision-making of designers and facilities management for upgrades and future design projects.
Potential for broadband acoustics to improve stock assessment surveys of midwater fishes
Authors: Bassett Christopher , Weber Thomas C. , Wilson Chris , De Robertis Alex
Published: November 2016

Acoustic-trawl surveys rely on a combination of backscatter measured with echosounders and species composition data from trawls to apportion the backscatter to different species and size classes. Narrowband echosounders have been widely used in this context for decades. Multi-frequency analysis of narrowband echosounder data has been shown to be effective for discriminating between diverse taxa (e.g., euphausiids vs. swimbladdered fishes) but distinguishing morphologically similar species (e.g., swimbladdered fishes) remains a major challenge. Previous work indicates that broadband backscatter techniques have the potential to improve such acoustic target characterizations by exploiting nearly continuous frequency spectra, but these methods have not been widely applied in fisheries surveys. The recent commercial availability of broadband transceivers is accelerating the evaluation of this technology. We present operational data from two broadband acoustic scattering systems: (1) 14-160 kHz and (2) 3-10 kHz used during surveys of walleye pollock (Gadus chalcogrammus) in the Gulf of Alaska and Eastern Bering Sea. The presentation focuses on the potential for: 1) discrimination among common species in the area and 2) utilization of swimbladder resonance to estimate the dominant size class in single-species fish aggregations. The implications for fish stock assessment surveys are considered.
Application of scanning acoustic and photoacoustic microscopes in orthopedic surgery
Authors: Hagiwara Yoshihiro , Saijo Yoshifumi
Published: November 2016

Demands for orthopedic surgery, decreasing pain and disabilities, are increasing in developed countries with older nations. Together with increasing number of patients, its cost is now rising. Among modalities for noninvasive diagnosing techniques, such as plain X-rays, computed tomography, magnetic resonance imaging (MRI), and ultrasonography (US), MRI is a powerful tool for evaluating anatomical abnormalities. However, location and economic limitations for routine use remain. US is quick and inexpensive with a higher resolution than MRI. US plays an important role in assessing musculoskeletal soft tissues. A scanning acoustic microscope (SAM) characterizes biological tissues by estimating the elastic parameters based on sound speed. Biomedical photoacoustic (PA) imaging has the unique capability of combining high optical contrast and high ultrasound resolution in a single modality. Osteoarthritis and frozen shoulder are the major problems in musculoskeletal diseases. Osteoarthritis is a degenerative joint disorder characterized by the progressive degeneration of articular cartilage, osteophyte formation, and subsequent joint space narrowing. Further, frozen shoulder is characterized with severe pain and a decrease in shoulder motion, which is caused by joint capsular stiffness. We applied SAM and PA to animal models for assessing.
Cumulative effect in the chronotropic effect in rat hearts caused by pulsed ultrasound
Authors: Coiado Olivia C. , O'Brien William D.
Published: November 2016

This study investigated the cumulative effect of a decreasing sequence of pulse repetition frequencies (PRFs) on the chronotropic effect via the application of 3.5-MHz pulsed ultrasound (US) on the rat heart. Two 3-mo-old female rat groups (n = 4 ea) were studied: control (US off) and PRF decrease. Rats were exposed to transthoracic ultrasonic pulses at ~0.25% duty factor at 2.0-MPa peak rarefactional pressure amplitude. Three PRF sequences were applied. The PRF started greater than that of the rat’s heart rate and was decreased sequentially in 1-Hz steps every 10 s (i.e., 6, 5 and 4 Hz—one sequence) for a total duration of 30 s. The total US exposure was 90 s (3-sequences). For the PRF decrease group, the ultrasound application resulted in an ~8% significant negative chronotropic effect after the first PRF sequence, ~9% significant negative chronotropic effect after the second PRF sequence, and ~10% significant negative chronotropic effect after the third PRF sequence. No significant changes were observed for the control group. The ultrasound application caused a negative chronotropic effect after US exposure for the PRF decrease group and a slight cumulative effect was observed. [Support: NIH Grant R37EB002641.]
A novel numerical simulation of acoustic Doppler effect using CIP-MOC method
Authors: Sonobe Takuro , Okubo Kan , Tagawa Norio , Tsuchiya Takao
Published: November 2016

Utilizing the Doppler effect (the Doppler frequency shift) is an effective method to detect the speed of the moving object; in particular, the measurement of the acoustic Doppler effect might be an important for recognition of the surrounding environment in the automatic operation and robot technology. To date, many researchers investigated acoustic numerical simulation methods. However, a numerical simulation considering acoustic Doppler effect has not been sufficiently developed yet. In this study, we employ the constrained interpolation profile (CIP) method, one of the methods of characteristics (MOC). A noticeable feature of the CIP method is that it allows analyses not only of sound fields on grid points, but also analyses of their spatial derivatives on grid points, whereas the CIP-MOC method adopts the co-located grid system. That is, sound field components (air pressure and vertical velocity) and their derivatives are located on the same grid, so that we can model accurate interface between different media. This feature is valuable for stable and low-dispersive computation of acoustic Doppler effect. In present study, we first perform some numerical simulations by the CIP-MOC method for sound propagation involving the Doppler effect and then demonstrate the effectiveness of this scheme.
Comparative study of a low frequency emergency siren to traditional siren technology
Authors: Angione Frank , Novak Colin , Imeson Chris , Lehman Ashley , Merwin Ben , Pagliarella Tom , Samardzic Nikolina , D'Angela Peter , Ule Helen
Published: November 2016

This study measures and compares the acoustic characteristics of a traditional electronic emergency siren and an innovative low frequency Rumbler siren technology. The Rumbler siren’s low frequency emissions can travel further and have a greater ability to penetrate and induce structure-bone excitation in nearby vehicle cabins compared to other siren technology. The result is a better ability to warn both nearby vehicles and pedestrians thus lessening the potential of emergency vehicle collisions. The siren technologies were evaluated using three measurement scenarios to determine acoustic localization characteristics, drive-by effectiveness, and the ability to overcome the problem shadowing phenomenon typical at congested intersections. A comparative analysis of the acoustical characteristics of the standalone siren and the addition of The Rumbler system provided insight in regards to the relative effectiveness of each siren mode. The siren system equipped with The Rumbler technology gave a noticeable increase in sound pressure level for each of the three test scenarios. Through analysis of the measured data, the overall performance of the emergency siren system with the Rumbler technology was shown to be a more effective emergency notification device compared to the standalone electronic siren.
Numerical simulations of detecting perforated slim hole length in formation with an acoustic method
Authors: Yang Shubo , Che Xiaohua , Qiao Wenxiao
Published: November 2016

Water-jet deep penetrating perforation, which utilizes high pressure water-jet to penetrate reservoirs, is a new well interference technology for increasing deliverability. The length of water-jet hole is a key parameter for evaluating water-jet effect. We simulated and compared acoustic fields both inside and outside water-jet hole in different conditions with the time-domain finite difference method. The water-jet hole in the modeling is 3 cm in diameter and 10 m in length. Based on the simulation results, we analyzed the feasibility to detect the length of water-jet hole mainly by adopting low frequency source. Simulation results show that the high frequency source can excite multiple waves inside the water-jet hole, including refraction P and S waves, pseudo-Rayleigh waves, and Stoneley waves. Thus, the signals received in borehole are complex. On the contrary, the low frequency source excites few modes inside the water-jet hole. Specifically, there are only Stoneley waves when the source frequency is lower than 1 kHz. The Stoneley wave velocity is approximately equal to the P wave velocity of the fluid. As a result, we can utilize the arrival time and the velocity of Stoneley waves to calculate the length of water-jet hole.
Numerical study of mean flow effect on sound propagation through an aerosol
Authors: Arslan Ersen , Özyöruk Yusuf , Caliskan Mehmet
Published: November 2016

Previous studies on the sound attenuation and dispersion in an aerosol consisting of air and water droplets have been extended to accommodate mean flow effects. A numerical methodology based on solution of one dimensional, linearized Euler equations in the frequency domain has been developed. The interactions between the fluid and particle phases have been considered to be through Stokesian drag force. First, the verification of the numerical code has been shown for the zero mean flow case with comparative evaluation of results available in literature. Next, the attenuation and dispersion results of both upstream and downstream flows have been presented. The comparison of results suggests that significant deviations exist for attenuation values between the stationary and the mean flow cases at the same frequencies. Keywords: Suspension Acoustics, Finite Difference in Frequency Domain (FDFD), Mean Flow Effect
Study on the principle of sound resonance in human whistling using physical models of a human vocal tract
Authors: Mori Mikio
Published: November 2016

The principle behind sound production in human whistling is relatively unknown. A good understanding of this principle would be beneficial to both trainer and trainee. Rayleigh identified whistling frequency as being determined by the mouth cavity and pointed out that earlier ideas that relate the sound-producing mechanism to the vibration of the lips are inaccurate. Wilson et al. reported that the human whistling resonant frequency is close to the Helmholtz resonant frequency, and through some physical-model-based experiments, they determined that the resonator can be excited by a flow through the smooth-edged orifices bounding the resonant cavity. Thus, the principles of whistling in terms of articulation have been reported to be based on the Helmholtz resonance. However, some whistlers can produce high-pitched sounds by blowing harder without changing the capacity of the resonance chamber, which is similar to a high-pitched sound produced by a wind instrument by air-column resonance. This work studies the principle of sound production during human whistling using physical models of a human vocal tract, which is obtained from an X-ray computed tomography image during whistling. We have demonstrated that the principle of resonance in human whistling includes not only the Helmholtz resonance but also an air-column resonance.
Numerical study on acoustic intensity of edge tone with change of jet velocity
Authors: Sho Iwagami , Kobayashi Taizo , Takahashi Kin’ya , Hattori Yuji
Published: November 2016

To understand the sounding mechanism of “air-jet” instruments we numerically study the acoustic intensity of edge tone, i.e., the sound source of “air-jet” instruments, with compressible LES and DNS comparing with experimental results. The edge tone is aerodynamic sound and we need to investigate the sound generation based on Lighthill’s theory. According to Lighthill’s theory, the acoustic intensity increases the eighth power of fluid velocity in transonic and subsonic ranges, but it may obey different rules in a range less than the subsonic. Indeed, we find with compressible LES that the edge tone has three stages, in each of which a different increasing rate is observed. In particular, the fundamental and second modes obey the second-power law in the second stage. The same result was obtained by an experiment provided by YAMAHA Corporation. To clarify the radiation mechanism of the edge tone, which exhibits the three stage, we have to calculate Lighthill’s sound source with high accuracy. So, we will show our effort in this direction: improving the calculation with compressible LES together with DNS, which gives very accurate results at low Reynolds numbers.
Measurement and numerical simulation of two-dimensional vibration of a single piano string
Authors: Naganuma Daisuke , Nomura Hideyuki , Kamakura Tomoo
Published: November 2016

A piano string begins to vibrate vertically as soon as a hammer strikes it. After the vertical vibration has begun, the string then starts to rotate owing to the generation of horizontal vibration. The rotation direction changes several seconds later, which suggests that the frequencies of the vertical and horizontal components of the vibration are slightly different. We previously reported an equivalent mechanical circuit model for physically elucidating such two-dimensional movements of the string. In this presentation, we show the verification and validation of the equivalent model by comparing with experiments. The movements of a string in low frequencies were observed using a high-speed camera and a mirror. In order to increase the measurement accuracy of displacement, interpolation technique was applied to the correlation of recorded images. It was noted that the frequency of a partial vibration of the string in the vertical direction is higher or lower than that in the horizontal direction to the soundboard. The rotation directions and the rotation change periods suggest how the soundboard acts on the generation of the partial vibration as mass-dominated or stiffness-dominated control at the string end, and to what extent does the soundboard affect the partial vibration of the string.
Evaluation of lateral attenuation for aircraft flyover and ground operation noise in airport noise modeling
Authors: Shinohara Naoaki , Hanaka Kazuyuki , Yamada Ichiro
Published: November 2016

At the side of flight path, especially on the side of runway, noise level observed greatly changes dependent on the effects of excess ground attenuation and meteorological conditions (in particular, vector wind and temperature gradient). Thus, taking account of appropriate adjustment for lateral attenuation in airport noise modeling leads to an increase in the reliability of predictions. This paper makes a review of equations for lateral attenuation such as SAE/AIR 1751, SAE/AIR 5662, and our equation 1751M, which is a modified equation we proposed based on AIR/1751 and is applicable under various meteorological conditions. It is also described with further issues related to the examining of lateral attenuation for aircraft flyover noise. In Japan, it is obligatory to take into account noise contributions of aircraft ground operations such as APU operation, taxiing, and engine run-up in airport noise modeling. However, we have not yet fully examined whether we can evaluate lateral attenuation of such ground noise similarly to flyover noise. It is not yet solved how to calculate excess ground attenuation under the effects of sound shielding by barriers or embankment. This paper also discusses how to evaluate lateral attenuation for noise due to aircraft ground operations.
Study of lateral attenuation for aircraft noise modeling based on field measurements near the airport
Authors: Hanaka Kazuyuki , Shinohara Naoaki , Yoshioka Hisashi
Published: November 2016

It is essential to appropriately evaluate effects of lateral attenuation in predicting aircraft noise at the side of flight path near the airport. About fifteen years ago, we examined the validity of existing equations of lateral attenuation, but noise characteristics of aircraft and engines have changed very much. Especially, in case of horizontal sound propagation over ground such as aircraft rolling on the runway, it is necessary to take into account that meteorological conditions may strongly affect lateral attenuation. Thus, we carried out field measurements of aircraft noise repeatedly on the side of runway at several airports including Narita Airport and examined the actual situation of lateral attenuation. As a result, it was found that lateral attenuation greatly changes dependent on meteorological conditions and that calculations from existing equations of lateral attenuation did not match measurements of lateral attenuation. Additionally, considering actual situation of land use around the airport, it is not always realistic to assume that the ground surface is flat and uniform as well as acoustically soft. It is sometimes necessary to assume that acoustic property of the ground changes. It is also necessary to evaluate lateral attenuation on conditions that the sound propagates over urbanized city area.
Numerical determination of parameter sensitivity of transmission loss in atmospheric sound propagation above a general ground surface
Authors: Hubbard Seth D. , Lechner David , Vignola Joseph F. , Ryan Teresa J. , Hall Melissa , Judge John A. , Turo Diego
Published: November 2016

A transmission loss model, similar to the sonar equation, is used to study the transmission loss in atmospheric sound propagation over ground. The model takes into account contributing factors from spreading loss, absorption, wind, temperature gradient, and ground impedance. Numerical predictions obtained with the Crank-Nicolson Parabolic Equation implementation are used to quantify the effects of these factors. The transmission loss sensitivity to these parameters will be presented. These sensitivity findings will be compared to a set of field measurements. An acoustic source is placed in an open field and six horizontally aligned microphones are used to record the signal. Microphones were spaced at regular intervals up to approximately 400 m away from the source and 1 meter above the ground. Temperature, atmospheric pressure, and relative humidity measurements were made concurrent with the acoustic recordings.
De-Dopplerization of acoustic signatures
Authors: Mobley Frank S. , Davis Brian S.
Published: November 2016

Shifting energy within and between adjacent fractional octave bands removes Doppler shifting in overflight measurements of acoustic signatures without complex resampling techniques and stationary requirements. Analyzing acoustic measurements with Fourier transforms to obtain spectral information requires complex resampling to overcome stationary signal requirements. A simple shifting of band energy obtained from fractional octave digital filters generates a de-Dopplerized spectrum without complex algorithms. A numerical equation is developed based on the fractional octave center frequency to define the amount of energy shifting required. This equation is applied to a numerical simulation and an overflight measurement to remove the Doppler effect in spectral data. The de-Dopplerization through application of energy shifting accurately removes vehicle motion effects from acoustic measurements without complex resampling.
Focus control of a nematic liquid crystal cell using ultrasound vibration
Authors: Shimizu Yuki , Koyama Daisuke , Taniguchi Satoki , Emoto Akira , Nakamura Kentaro , Matsukawa Mami
Published: November 2016

Nematic liquid crystals used in optical devices such as liquid crystal displays are controlled by the electric fields. Although indium tin oxide (ITO) is generally employed as the transparent electrode material to apply the electric field, it includes the rare metal indium and needs complicated processes such as sputtering deposition method. Our group has been investigating control techniques of molecular orientation of liquid crystals using ultrasound. In this study, we have applied these techniques to optical variable-focus lenses and the optical characteristics were examined. The ultrasonic liquid crystal cell has a simple structure with no transparent electrodes; it consists of has an annular ultrasound PZT transducer (inner diameter: 30 mm; thickness: 2 mm) and a liquid crystal cell in which a nematic liquid crystal layer (thickness: 25 μm) was formed between two glass substrates (thickness: 0.7 mm) and orientational films. The concentric flexural vibration modes could be generated on the cell at the several resonance frequencies, and the liquid crystal molecular orientation was changed by the acoustic radiation force. The transmitted light through the liquid crystal cell was focused, and the focal length could be controlled by the input signal.
Performance analysis of finite-difference time-domain schemes for acoustic simulation implemented on multi-core and many-core processor architectures
Authors: Imai Ryo , Suzuki Yukihisa , Okubo Kan , Katori Yuta , Kawada Naoki
Published: November 2016

There have been many discussions about hardware-accelerations for the large-scale finite-difference time-domain (FDTD) method to deal with various wave dynamics in scientific and engineering computations. Recently, there is growing interest in many-core based parallel computing with graphics processing unit (GPU) or many integrated Core (MIC) accelerators. Therefore, it is worth applying those to large-scale and long-time acoustic simulation for FDTD methods. In this paper, performance analyses are performed for three types of acoustic FDTD schemes, which are FDTD(2,2), FDTD(2,4) and wave equation FDTD (WE-FDTD)(2,2), implemented on GPU, Intel MIC, and multi-core central processing unit (CPU). Here, FDTD(T, S) denotes Tth-order accuracy for the time derivative and Sth-order accuracy for the spatial derivative, respectively. The parallelized FDTD schemes are implemented with Compute Unified Device Architecture (CUDA) and OpenACC, respectively, on GPU, and OpenMP for MIC and multi-core CPU. As a method for performance analysis, we employ the modified roofline model which adds the concept of cache hit ratio to operational intensity. The analysis provides performance comparison results of attainable performance and measured performance for each FDTD scheme and each processor. We performed software optimizations for MIC based on the performance analysis and achieved 78%-91% of attainable performance on MIC.