bluuebunny/crossref_metadata_2025 huggingface dataset:
Processing two stimuli simultaneously: Switching or sharing?
Authors: Gallun Frederick J. , Mason Christine R. , Kidd Gerald
Published: October 2013

This study explored whether listeners can perform two auditory tasks simultaneously or whether they must switch rapidly between tasks. The stimuli were two simultaneous speech streams (sentences) processed into sets of mutually-exclusive narrow frequency bands. One was presented to each ear and listeners reported either the keywords from the sentences (Task 1, recognition) or simply whether or not a sentence had been presented (Task 2, detection). For both sentences and tasks, overlapping bands of noise were presented at a level that reduced performance to below 90% correct in a single-stream reference condition. Listeners were informed of which stream to report either before or after stimulus presentation. The two tasks were either the same (Task 1 at both ears) or different (Task 1 on the right, Task 2 on the left). The effect of having the opportunity to rapidly switch between sentences was examined by presenting full sentences or only the keywords. Interference occurred primarily when the tasks were the same in both ears and was greatest when the target ear was not specified in advance. Presenting only the keywords hurt single-stream performance but did not increase interference in the different-task case, arguing against a rapid-switching explanation. [Work supported by NIH/NIDCD.]
Explaining two-tone suppression and forward masking data using a compressive gammachirp auditory filterbank
Authors: Irino Toshio , Patterson Roy
Published: October 2013

The gammatone filter was imported from auditory physiology to provide a time-domain version of the roex auditory filter and enable the development of a realistic auditory filterbank for models of auditory perception. The gammachirp auditory filter was developed to extend the domain of the gammatone auditory filter and simulate the changes in filter shape that occur with changes in stimulus level. Recently, the gammachirp was extended to explain the level-independent frequency glide of the impulse response and a large volume of simultaneous masking data quantitatively. Although this could be implemented with a static filter, we used a time-varying filter whose active component is an IIR asymmetric compensation filter. In this case, it is necessary to estimate the signal level that controls the level dependency, and explain how the level measurement produces the time course of threshold observed in forward masking experiments. In this talk, we propose a new implementation of the time-varying, compressive gammachirp auditory filterbank to explain two-tone suppression and forward masking data qualitatively. We will also show that the system can resynthesize compressed speech sounds and so provide the basis for a gammachirp analysis/synthesis filterbank. [Work supported by GASR(B)(2) No. 15300061, JSPS.]
Behavioral estimates of level-dependent shifts in the vibration pattern of the apical region of the basilar membrane
Authors: Barrios Luis F. , Lopez-Poveda Enrique A. , Alves-Pinto Ana
Published: October 2013

The best frequency of any given site on the BM shifts to a different value as the stimulus level increases. For basal sites, the shift occurs towards lower frequencies. For apical sites, however, the direction of the shift is unclear. Auditory nerve data [e.g., Rose et al., J. Neurophysiol. 34, 685–699 (1971)] suggest that shifts may not occur or may occur toward higher frequencies. The present work investigates which is the case in human. To do it, psychophysical tuning curves were measured for three normal-hearing listeners using forward masking. The level of a masker tone required to just mask a fixed, low-level probe tone was measured for different masker-probe time intervals. The duration of the interval was adjusted as necessary to obtain PTCs for the widest possible range of masker levels. Probe frequencies of 125, 250, and 500 Hz were considered. Masker frequencies ranged from 0.5 to 2.0 times the probe frequency. A clear shift toward lower frequencies occurred for all probe frequencies for one listener only. For the other two listeners, shifts were not observed for any probe frequency. No clear shifts toward higher frequencies were observed. [Work supported by Spanish FIS PI020343 and G03/203.]
The fading of auditory memory
Authors: Li Liang , Huang Juan , Kong Lingzhi , Huang Ying , Wu Xihong , Chen Jing , Huang Qiang , Yao Yuan , Qi James , Schneider Bruce
Published: October 2013

Due to auditory memory, the auditory system is capable of maintaining a detailed representation of arbitrary waveforms for a period of time, so that a broadband noise and its delayed copies can be perceptually fused. This auditory memory would be critical for perceptually grouping correlated sounds and segregating uncorrelated sounds in noisy, reverberant environments. Its fading process over time was investigated in the present study at the behavioral level, using a break in correlation (BIC, a drop of inter-sound correlation from 1.00 to 0 and then return to 1.00) between two correlated broadband noises. The results show that with the rise of inter-sound delay from 2 to 10 ms under either headphone-stimulation or loudspeaker-stimulation conditions, the shortest BIC duration necessary for listeners to correctly detect the occurrence of the BIC increased rapidly. This elevation in the duration threshold was faster under the headphone-stimulation condition than the loudspeaker-stimulation condition. Also, the listeners reaction time in response to the BIC but not that to a comparable silent gap elongated quickly with the increase in the inter-sound delay from 1 to 8 ms. Thus the auditory memory of fine structures fades rapidly after the sound waves are received. [Work supported by MSTC and NSERCC.]
Wideband reflectance in normal and otosclerotic ears
Authors: Shahnaz Navid , Bork Karin
Published: October 2013

For years immittance has been used in order to help diagnose middle ear pathologies. Specifically, multi-frequency tympanometry (MFT) is able to relate information regarding the mechano-acoustical characteristics of the middle ear system. In the past two decades a new method of middle ear measurement, wideband reflectance (WBR), has been introduced. WBR is the ratio of energy reflected from the surfaces of the ear canal and middle ear on its way to the cochlea in relation to the energy that reaches the surface, or incident energy. This ratio is known as energy reflectance. This paper adds to the limited normative data available, as well as explores whether these normative data have a clinical utility in the diagnosis of otosclerosis. Descriptive statistics were gathered from 62 (115 ears) Caucasian normal hearing adults as well as in seven patients (seven ears) with otosclerosis. All of the otosclerotic patients in this study deviated from the normative values on at least one of the four WBR parameters of power absorption, admittance, susceptance, or conductance even when their MFT results were within normal limits. Although only seven patients were tested, these results provided evidence in favor of the utility of WBR for diagnosis of otosclerosis.
Medium frequency vibration modeling of cracked plates using hierarchical trigonometric functions
Authors: Pinsonnault Jérôme , Masson Patrice , Micheau Philippe , Mrad Nezih
Published: October 2013

A modeling tool is proposed to describe the vibration behavior of pristine and damaged plates in the medium frequency range (below 10 kHz). This tool is intended to provide a platform for the development and assessment of damage detection algorithms for aircraft structural health monitoring applications. The proposed analytical model employs a Hierarchical Trigonometric Function Set (HTFS) to characterize homogeneous plates with through cracks. This approach takes advantage of the very high order of stability of the HTFS [O. Beslin and J. Nicolas, J. Sound Vib. 202, 633–655 (1997)] to approximate the effects of a small crack in a plate for all combinations of classical boundary conditions (e.g., CFSC, CCFF, FSFS). The model is first presented and then assessed for healthy and cracked CCCC plates with eigenvalues and eigenmodes presented in the literature. For a healthy square plate, numerical results provide good agreement up to the 1000th mode while, for a cracked rectangular plate, good agreement is obtained up to the 3rd mode, corresponding to the highest mode order available in the literature. Wave propagation simulation obtained from HTFS shows the scattering around the cracks in the plates. Experimental validation of the model is conducted both in frequency and time domains for healthy and cracked plates. [Work supported by the Consortium for Research and Innovation in Aerospace in Quebec (CRIAQ) and Defence R&D Canada.]
Optimal energy dissipation in a semi-active friction device
Authors: Buaka Paulin , Micheau Philippe , Masson Patrice
Published: October 2013

A semi-active device is presented for vibration control using energy dissipation by dry friction at contact surfaces. Semi-active behavior is provided by two piezoelectric stack actuators driven in real time to apply a normal force on a mobile component through two friction pads. Theoretical and experimental results show that there is an optimal constant normal force to maximize the energy dissipated for the case of a harmonic disturbance. In order to improve the energy dissipation by real time control of the normal force, two nonlinear controllers are proposed: (1) the Lyapunov method leading to a nonlinear bang-bang controller law and (2) the feedback linearization approach leading to equivalent viscous friction. The implementation of both strategies is presented and both are experimentally assessed using a clamped-free beam with the semi-active device attached to the beam. It is shown that a proper choice for the parameters of the controllers leads to an increased energy dissipation with respect to the case where the normal force is constant. This dissipation is further increased by adjusting a phase shift in the nonlinear feedback loop in order to avoid a stick-slip motion of the mobile component.
Energy sinks: Vibration absorption by an optimal set of undamped oscillators
Authors: Koç Ilker , Carcaterra Antonio , Xu Zhaoshun , Akay Adnan
Published: October 2013

This presentation offers the concept of energy sinks as an alternative to conventional methods of vibration absorption and damping. A prototypical energy sink envisioned here consists of a set of oscillators attached to, or an integral part of, a vibrating structure. The oscillators that make up an energy sink absorb vibratory energy from a structure and retain it in their phase-space. In principle, energy sinks do not dissipate vibratory energy as heat in the classical sense. The absorbed energy remains in an energy sink permanently so that the flow of energy from the primary structure appears to it as damping. This paper demonstrates that a set of linear oscillators can collectively absorb and retain vibratory energy with near irreversibility when they have a particular distribution of natural frequencies. The approach to obtain such a frequency response is based on an optimization that minimizes the energy retained by the structure as a function of frequency distribution of the oscillators in the set.
Comparison of cues in auditory selective and divided attention
Authors: Lee Jae hee , Humes Larry E.
Published: October 2013

This study investigated auditory selective and divided attention in ten normal-hearing listeners. Subjects listened to two simultaneous sentence-like utterances from the Coordinate Response Measure (CRM) speech corpus at 90 dB SPL in dichotic or monotic listening conditions. This corpus has the following format, Ready (call sign), go to (color) (number), now, with all possible combinations of call signs (8), colors (4) and numbers (8). In all conditions, the listener identified the color-number coordinates spoken by the target talker. The target talker was identified by a cue provided either prior to (selective attention) or following (divided attention) the presentation of the two simultaneous utterances. In the first experiment, either the ear or the call sign served as the cue for the target talker in monotic or dichotic listening conditions. In the second experiment, talker gender served as the cue in monotic listening conditions. Across both experiments, performance for selective attention was superior to that for divided attention. Performance for ear or gender cueing was better than for call sign. Analysis showed that 80% of errors were due to intrusions from the competing utterance, supporting an informational (attention), rather than energetic, form of masking. [Work supported, in part, by NIH R01 AG08293.]
Perceptual strategies for identifying vowels produced by speakers with dysarthria
Authors: Bunton Kate
Published: October 2013

It has been previously reported that changes to the fundamental frequency contour of vowels influences their identification [e.g., H. Traunmuller, J. Acoust. Soc. Am. 69, 1465–1475 (1981)]. Similar changes in vowel identification have been demonstrated for some listeners when the F0 contour of a dysarthric speaker has been modified (e.g., flattened or enhanced) [Bunton (2004)]. These listeners appear to rely on F0−F1 space for identification of vowel height; this strategy is consistent with a perceptual model of vowel recognition described by A. Syrdal and H. Gopal [J. Acoust. Soc. Am. 79, 1086–1100 (1986)]. Other listeners, however, appear to utilize different acoustic cues to identify a given vowel. This study focused on defining those perceptual strategies. Multi-dimensional plots of acoustic cues likely to influence vowel perception are used to illustrate perceptual strategies that may have been used by these listeners for identification of vowels in the speech of individuals with dysarthria associated with Parkinson disease. [Work supported by NIH R03 DC005902.]
Effects of hearing impairment on the perception and neural representation of time-varying spectral cues
Authors: Harkrider Ashley W. , Plyler Patrick N. , Hedrick Mark S.
Published: October 2013

Differences in phonetic boundaries versus normal controls suggest that listeners with hearing impairment (HI) have difficulty categorizing stop consonant place of articulation based solely on the dynamic spectral information present in the second formant transition (F2), even when the stimuli are amplified. This may be due to a degraded ability of the central auditory nervous system to process time-varying spectral cues despite ensuring overall audibility. However, increasing the overall level of the stimuli may not result in improved audibility of F2. To determine if spectral shaping of F2 improves performance of listeners with HI, psychometric functions and N1-P2 cortical responses were compared in 10 older listeners with normal hearing versus 10 older listeners with HI. Stimuli were synthetic consonant-vowels along a /ba/-/da/-/ga/ place-of-articulation continuum in an unshaped and shaped condition. Generally, behavioral and N1-P2 results indicate that, with shaping, categorization of /d/ and /g/ improves. These findings suggest that enhanced audibility of F2 through spectral shaping does improve perception of stop consonant stimuli. However, categorical boundaries for the individuals with HI are shifted lower in frequency with shaping for all phonemes versus normal controls, indicating that enhancing audibility improves but does not completely normalize categorization performance.
Ferret and its applications
Authors: Bedard Jacques
Published: October 2013

Ferret is an acoustic system that detects, recognizes and localizes the source and direction of small arms fire. The system comprises a small array of microphones and pressure sensors connected to a standard PC-104 computer that analyzes, displays, reports and logs the parameters of a recognized shot. The system operates by detecting and recognizing the ballistic shock wave created by the supersonic bullet, combined with the muzzle blast wave propagating from the weapon. The Canadian Land Force Test and Evaluation Unit evaluated a vehicle-mounted version of the system and recommended deployment of the system during peacekeeping missions. The system is the result of a collaborative effort between Defence R&D Canada and MacDonald Dettwiler and Associates. This presentation describes the hardware and software components of the system along with the current and future applications of the system.
Dominant source of background reverberation during the Acoustic Clutter 2003 experiment
Authors: Donabed Ninos , Ratilal Purnima , Makris Nicholas
Published: October 2013

Reverberation data from the Acoustic Clutter 2003 experiment on the New Jersey Continental shelf are analyzed to provide estimates of the background scattering strength over wide areas of the environment as a function of time. We corrected the acoustic data in the 390–440 Hz range for two-way transmission loss modeled using the range-dependent parabolic equation, the spatially varying beampattern of the receiving array, and source level to obtain estimates of the scattering strength per unit area of the environment. Data from regions of space devoid of strong clutter were statistically analyzed to provide a temporal and spatial characterization of the background scattering strength. They were then compared to scattering strength levels deduced from modeling from a variety of scatterers including schools of fish, the sea bottom, internal waves and surface waves. Analysis indicates that the dominant sources of background reverberation can be either low density fish schools or the sea bottom.
Statistical characterization of sonar-like clutter observed on the STRATAFORM during the 2003 Acoustic Clutter Experiment in the 400–1500 Hz region
Authors: Preston John , Abraham Douglas
Published: October 2013

In 2003 ONR sponsored the Acoustic Clutter Experiment to study shallow water scattering and clutter in the STRATAFORM area off New Jersey. Sources were bistatic coherent pulses from a vertical array. The receiver was the Five Octave Research Array (used horizontally). The STRATAFORM is known to have benign surface morphology but contains many buried river channels and other sub-surface horizons. MIT researchers have shown fish to be a primary source of the observed clutter and reverberation. The K-distribution’s shape and scale parameters have been shown to be useful in describing non-Rayleigh behavior. Statistical characterization is presented as a function of location. The ‘‘bandwidth’’ effect is shown where the shape parameter first decreases inversely proportional to bandwidth but then increases in a trend back toward the Rayleigh distribution at higher bandwidths. The shape parameter estimates are well fit by an elongated patch model of Abraham and Lyons. Differences between the 2003 and 2001 data taken in the same area are discussed. It is believed that the sound speed profiles in 2003 lead to more bottom interaction than in 2001 producing a larger time spread in the multipaths leading to observed differences. [Work supported by ONR Code 32, Grant N00014-05-1-0156.]
Calculation of scattering from underwater targets using the equivalent source technique
Authors: Abawi Ahmad T. , Porter Michael B.
Published: October 2013

The equivalent source technique is a method of computing scattering and radiation from a target by replacing the target by a distribution of discrete sources, whose complex amplitudes are determined by applying the boundary condition on the total field. The advantage of using this method, particularly in underwater acoustics, is that it essentially transforms the scattering and propagation problems into just a propagation problem, where the target can be treated as a distribution of sources rather than an impedance discontinuity. In this paper the equivalent source technique and different propagation models such as the normal mode, the parabolic equation and the fast field method are used to compute scattering from various target shapes/properties placed in the ocean waveguide. The results are compared with those obtained from other numerical codes. In addition, the relationship between the equivalent source technique with boundary element method (BEM) and the method of moments (MoM) is investigated.
Strain differences in auditory sensitivity in canaries bred for song and plumage
Authors: Lauer Amanda , Brittan-Powell Elizabeth , Lohr Bernard , Dooling Robert
Published: October 2013

Canaries have been domesticated for well over 100 years. They have been bred for specific characteristics such as song, plumage, or body shape. Here we measured audiograms in several canary strains using both behavioral (operant conditioning) and physiological (auditory brainstem responses) methods. Overall, there was a good correspondence between behavioral and ABR audiograms, but there were differences in audiogram shape and sensitivity between strains. Belgian Waterslager canaries bred for low-pitched song had elevated high frequency thresholds, while Spanish Timbrado canaries bred for high-pitched song had slightly better high frequency thresholds than canaries that were not bred for song. Other strains showed intermediate sensitivity. These results suggest there can be more variability in hearing within a species than previously thought and that these differences are correlated with other behavioral or morphological traits. [Work supported by DC00198, DC001372, DC04664-01A2, and DC005450.]
Computational and experimental models for sound transmission in the pulmonary system and chest to aid in medical diagnosis
Authors: Acikgoz Serhan , Royston Thomas J. , Ozer M. Bulent , Mansy Hansen A. , Sandler Richard H.
Published: October 2013

Acoustic wave propagation in the pulmonary system and torso is simulated by coupling a numerical acoustic boundary element model that predicts sound propagation throughout the solid tissues with a proven comprehensive analytical model for sound wave propagation in the airways of the bronchial tree that is valid up to at least 2 kHz. This approach enables modeling various pathologies that result in structural changes in the lung and/or changes in breath sound source and strength. The model may be also used to predict the resulting acoustic changes measured by acoustic sensors, e.g., stethoscopes, accelerometers, or other skin-contact sensors. Experimental studies in a novel lung phantom model are used to partially validate the computational model. This study focuses on low audible frequencies, i.e., less than 2 kHz. This range encompasses naturally generated respiratory sounds that have been shown to have diagnostic value, as well as externally-introduced vibro-acoustic stimuli used for diagnosis. [Work supported by NIH EB 003286-01.]
Perceptual development of phonotactic features in Japanese infants
Authors: Mugitani Ryoko , Fais Laurel , Kajikawa Sachiyo , Amano Shigeaki , Werker Janet
Published: October 2013

Acceptable phonotactics differ among languages. Japanese does not allow consonant clusters except in special contexts and this phonotactic constraint has a strong effect on adults speech perception system. When two consonants follow one another in nonsense words, adult Japanese listeners hear illusory epenthetic vowels between the consonants. The current study is aimed at investigating the influence of language-specific phonotactic rules on infants’ speech perception development. Six-, 12-, and 18-month-old infants were tested on their sensitivity to phonotactic changes in words using a habituation-switch paradigm. The stimuli were three nonsense words: ‘‘keet (/ki:t/),’’ ‘‘keets (/ki:ts/),’’ and ‘‘keetsu (/ki:tsu/).’’ ‘‘Keetsu’’ perfectly follows Japanese phonotactic rules. ‘‘Keets’’ is also possible in devoicing contexts in fluent speech, but the acceptability of ‘‘keets’’ for adult native Japanese speakers is much less than ‘‘keetsu.’’ ‘‘Keet’’ is phonotactically impossible as a Japanese word. The results indicate the existence of a developmental change. Twelve months and older infants detected a change from the acceptable Japanese word ‘‘keetsu’’ to the possible but less acceptable word ‘‘keets.’’ However, discrimination between ‘‘keets’’ and the non-Japanese ‘‘keet’’ is seen only in 18-month infants. Implications for infants’ speech perception with relation to language specific phonotactical regularities will be discussed.
Cross-modal perception of vowels, stops, and approximants using reduced-formant stimuli
Authors: Rubin Philip , Best Catherine , Ramsay Gordon , Frost Stephen , Repp Bruno
Published: October 2013

This paper explores the relationship between audio and video representations of speech, by examining how information in particular formants is complemented by facial information, for different classes of speech sounds. Specifically, we investigate whether acoustic information removed by deleting formant combinations that usually signal contrasts between vowels (F1,F2), stops (F2) and approximants (F3) can be replaced by optical information derived from the talking face. Simultaneous audio and video recordings were made of speakers uttering CVC nonsense syllables constructed from vowels, stops, and approximants exhibiting varying degrees of facial motion and varying dependence on individual formant cues. Synthetic stimuli were then resynthesized from combinations of one, two, and three formants using a parallel formant synthesizer. Subjects performed an auditory identification task with stimuli presented in an audio-only condition, followed by a separate block of stimuli presented in an audio-visual condition. Source effects were examined using an inverse-filtered source and a synthetic source with constant source characteristics. There were no differences between source conditions, but differences were obtained between the audio and audio+video conditions that reflect the relationship between facial and formant dynamics. These results complement recent research on perception of reduced video information and complete audio information [L. Lachs and D. B. Pisoni, J. Acoust. Soc. Am. 116, 507–518 (2004)]. [Work supported by NIH.]
Perception of a Japanese moraic obstruent in an identification task
Authors: Amano Shigeaki , Mugitani Ryoko , Kobayashi Tessei
Published: October 2013

Native Japanese speakers perceive a moraic obstruent when the closure duration between successive moras is longer than a normal obstruent. However, it has not been well clarified how the perception of the moraic obstruent relates to the closure and neighboring moras’ duration. To investigate this point, a perceptual experiment was conducted with stimuli consisting of two-mora nonsense syllables with a closure between the moras (/bipa/, /guku/, /kuku/, /kuto/, and /tapi/). The closure duration was shortened or lengthened in 10-ms steps. The duration of the first mora was modified by changing its vowel duration to 50%, 100%, and 150% by the STRAIGHT method. Forty native Japanese speakers identified whether the nonsense syllable contained a moraic obstruent with the 2AFC method. Results showed that the perceptual boundaries of the moraic obstruent were 182 ms (SD=13.2 ms), 204 ms (SD=14.7 ms), and 222 ms (SD=16.6 ms), respectively, with 50%, 100%, and 150% vowel durations in the first mora, and that a logistic function fits the identification ratio very well. The results indicated that the perception of a moraic obstruent depends on both closure duration and the duration of neighboring moras. They also suggest that the perception would be categorical.
Perception of a Japanese moraic obstruent in a discrimination task
Authors: Kobayashi Tessei , Mugitani Ryoko , Amano Shigeaki
Published: October 2013

Previous research with an identification task suggests that native Japanese speakers perceive a moraic obstruent categorically (Amano et al., 2005). However, it is still unclear whether the suggestion would be confirmed by other tasks. This study used an AX discrimination task to investigate whether the performance is highly sensitive around the perceptual boundaries that were obtained from the identification task. Native Japanese speakers (N=40) were presented with a pair of two-mora nonsense syllables (/bipa/, /guku/, /kuku/, /kuto/) and then required to judge whether the stimulus pair was acoustically identical. The stimulus set was produced by reducing or increasing the closure duration between the successive moras in 5-ms steps (−95 to 240 ms). Results showed that the participants discriminated more precisely around closures duration ranging from approximately 150 to 180 ms (/bipa/: 180 ms, /guku/: 160 ms, /kuku/: 155 ms, /kuto/: 175 ms). Although the results indicate, to some degree, the possibility of perceptual categorization of the moraic obstruent, the high sensitivity peak in each stimulus type was slightly shifted from the perceptual boundaries in the identification task.
Haptic information enhances auditory speech perception
Authors: Johannsdottir Kristin M. , Gibrail Diana , Bryan Gick , Yoko Ikegami , Muehlbauer Jeff
Published: October 2013

Studies of tactile enhancement effects on auditory speech perception [Reed et al., JSHR, 1978, 1982, 1989] have traditionally used experienced, pre-trained subjects. These studies have left unanswered the basic questions of whether tactile enhancement of speech is a basic component of human speech perception or a learned association [Fowler, JPhon, 1986; Diehl and Kluender, Ecol. Psych., 1989], and which aspects of the signal are enhanced through this modality. The present study focuses exclusively on tactile enhancement effects available to naive speakers. In a speech-masked environment, naive subjects were tasked with identifying consonants using the Tadoma method. Half of the stimuli were presented with tactile input, and half without. The results show that all subjects gained considerably from tactile information, although which part of the tactile signal was most helpful varied by subject. The features that contributed most to consonant identification were aspiration and voicing. [Work supported by NSERC.]
A consonant-vowel-consonant display as a computer-based articulation training aid for the hearing impaired
Authors: Meng Fansheng , Rodel Eugen , Zahorian Stephen
Published: October 2013

Computer-based visual speech training aids are potentially useful feedback tools for hearing impaired people. In this paper, a training aid for the articulation of short Consonant-Vowel-Consonant (CVC) words is presented using an integrated real-time display of phonetic content and loudness. Although not yet extensively tested with hearing-impaired listeners, real-time signal processing has been developed, flow-mode displays have been developed, and accuracy tests have been completed with a large database of CVC short words. A combination of Hidden Markov Models and time-delay neural networks are used as the primary method for the acoustic-phonetic transformations used in the display. [Work partially supported by NSF grant BES-9977260.]
Stop consonant perception in silent-center syllables
Authors: DeRuiter Mark , Ramachandran Virginia S. , Rosen Sheryl J.
Published: October 2013

Silent-center (SC) syllables are consonant-vowel-consonant syllables with the steady-state vowel portion excised from them. These syllables are appealing for research of stop-consonants because they retain the complexity, brevity, and rapid changes inherent in formant transitions while presumably eliminating temporal masking by the vowel. However, questions exist as to whether or not SC syllables are processed in the same manner as their full-vowel (FV) counterparts (i.e. are they processed as speech units or as sounds?). Data is reviewed from a series of experiments which examined listeners discrimination, labeling, and response time for synthesized consonant-vowel-consonant syllables in FV and SC conditions. Results from 3 experiments with typical listeners reveal that: (1) discrimination is significantly better in the SC condition; (2) consonant labeling on a /bab/ to /dad/ continuum is poorer in the SC condition and is significantly poorer at the category boundary; (3) discrimination response-time (RT) is significantly shorter in the SC condition. Labeling and discrimination results reveal that listeners processed the stop-consonants in these SC syllables in a less-categorical manner than in the FV syllables. Taken together with significantly different response-times, these results may indicate that listeners utilize a different mode of processing for SC syllables.
Voice F0 responses elicited by perturbations in pitch of auditory feedback during English speech and sustained vowels
Authors: Bauer Jay J. , Larson Charles R.
Published: October 2013

Twenty-one native speakers of American English were asked to repeatedly inflect the pitch of either the first or second syllable of an English speech phrase or produce non-word sustained vowels while listening to amplified auditory feedback. Brief upward and downward perturbations in pitch of auditory feedback were introduced in real time shortly after vocal onset. Resultant changes in voice F0 due to perturbations in pitch were compared across vocal conditions and perturbation direction. Data indicated that auditory feedback was used in real-time to stabilize voice F0 during both normal English speech and sustained vowels. Incomplete compensatory corrections in voice F0 due to the perturbations in pitch of auditory feedback were prevalent during both dynamic speech (gain: ∼12.7%) and static sustained vowel phonations (gain: ∼19.3%), and appear to be regulated by similar corrective mechanisms. However during dynamic speech, voice F0 was modulated across syllable boundaries in a task-dependent manner according to syllable pitch inflection. Thus, voice F0 responses appear to help maintain the underlying suprasegmental meaning of a speech phrase by delaying the onset of the voice F0 response to coincide with the pitch-inflected syllable. [Work supported by NIH Grant No. F31 DC005874.]
Optimizing multistatic sonobuoy placement
Authors: DelBalzo Donald R. , Rike Erik R. , McNeal David N.
Published: October 2013

Sonobuoy patterns for monostatic sensors were developed during the Cold War for deep, uniform underwater environments, where a simple median detection range defined a fixed inter-buoy spacing (usually along staggered lines). Oceanographic and acoustic conditions in littoral environments are so complex and dynamic that spatial and temporal variability of low-frequency signal and noise fields destroys the basic homogeneous assumption associated with standard tactical search concepts. Genetic Algorithms (GAs) have been applied to this problem to produce near-optimal, non-standard search tracks for monostatic mobile sensors that maximize probability of detection in such inhomogeneous environments. The present work describes a new capability, SCOUT (Sensor Coordination for Optimal Utilization and Tactics), to simulate multistatic distributed-sensor geometries and to optimize the locations of multistatic active sonobuoys in a complex, littoral environment. This presentation reviews the GA approach, discusses the new chromosome structure, and introduces a new target-centric geometry. The results show that (a) standard patterns are not optimal even for a homogeneous environment, (b) small distributed sensor clusters are preferred, and (c) standard patterns are grossly ineffective in inhomogeneous environments where 20% improvements in detection are achieved with SCOUT. [Work supported by NAVAIR.]
Macroscopic sonic crystals in a wave guide
Authors: Dacol Dalcio K. , Orris Gregory J. , Calvo David C.
Published: October 2013

Periodical arrays of long, parallel cylinders have been shown in the published literature to exhibit acoustical properties which are analogous to the electronic properties of certain crystalline solids. Thus there are frequency bands for which no acoustic propagation through the array is allowed, with those band gaps being directionally dependent. The properties of such arrays in wave guides are examined in this work. Particular emphasis is put in investigating the properties of those arrays in wave guides that are idealized models of shallow water oceanic wave guides. The effects of those arrays on the propagation of normal modes is investigated in detail. The possibility of using such arrays in the construction of large scale underwater devices such as filters and lenses is also discussed. [Work supported by ONR.]
Classroom acoustics: Three pilot studies
Authors: Smaldino Joseph J.
Published: October 2013

This paper summarizes three related pilot projects designed to focus on the possible effects of classroom acoustics on fine auditory discrimination as it relates to language acquisition, especially English as a second language. The first study investigated the influence of improving the signal-to-noise ratio on the differentiation of English phonemes. The results showed better differentiation with better signal-to-noise ratio. The second studied speech perception in noise by young adults for whom English was a second language. The outcome indicated that the second language learners required a better signal-to-noise ratio to perform equally to the native language participants. The last study surveyed the acoustic conditions of preschool and day care classrooms, wherein first and second language learning occurs. The survey suggested an unfavorable acoustic environment for language learning.
Acoustic environment challenges for the unique communication conditions in group learning classes in elementary school classrooms
Authors: Sutherland Louis , Lubman David , Pearsons Karl
Published: October 2013

Unlike the traditional ‘‘sage-on-the-stage’’ configuration of many K–12 classrooms, the group learning or ‘‘guide-on-the-side’’ configuration does not involve communication between a teacher in front of a seated class of 20 to 30 students. Instead, it can involve, most of the time, communication between the teacher and each of several small groups of students interacting, aurally, with each other. To maintain the desired 15 dB signal-to-noise ratio intended as the rationale for the ANSI standard, S12.60-2002 on classroom acoustics, the ‘‘noise’’ heard by participants in one of the groups is likely to include the speech levels generated by the participants in the other groups as well as the background noise in the unoccupied classroom. Thus, specification of the speech level within (i.e. the ‘‘signal’’), and between (i.e. part of the ‘‘noise’’) the learning groups, must be considered. Data available to evaluate these speech levels are reviewed and possible models considered to account for the Lombard effect for voice levels of both the teacher and the students. Some of the gaps in these data are suggested as a challenge to stimulate further studies on speech levels of teachers and students in a wide range of communication conditions.
A retrospective on hydroacoustic assessment of fish passage in Alaskan rivers
Authors: Burwen Debby , Fleischman Steve , Maxwell Suzanne , Pfisterer Carl
Published: October 2013

The Alaska Department of Fish and Game (ADFG) has enumerated fish stocks in rivers for over 30 years using a variety of acoustic technologies including single-, dual-, and split-beam sonar. Most recently, ADFG has evaluated a relatively new sonar technology at several sites in Alaska to determine its applicability to counting migrating fish in rivers. The new system, called a Dual frequency IDentification SONar (DIDSON), is a high-definition imaging sonar designed and manufactured by the University of Washington’s Applied Physics Lab for military applications such as diver detection and underwater mine identification. Results from experiments conducted in 2002–2004 indicate that DIDSON provides significant improvements in our ability to detect, track, and determine the direction of travel of migrating fish in rivers. One of the most powerful uses of the DIDSON has been to combine its camera-like images of fish swimming behavior with corresponding split-beam data. These linked datasets have allowed us to evaluate the effects of fish orientation and swimming behavior on echo shape parameters that have proven useful in the classification of certain fish species.
Observation of cavitation during shock wave lithotripsy
Authors: Bailey Michael R. , Crum Lawrence A. , Pishchalnikov Yuri A. , McAteer James A. , Pishchalnikova Irina V. , Evan Andrew P. , Sapozhnikov Oleg A. , Cleveland Robin O.
Published: October 2013

A system was built to detect cavitation in pig kidney during shock wave lithotripsy (SWL) with a Dornier HM3 lithotripter. Active detection, using echo on B-mode ultrasound, and passive cavitation detection (PCD), using coincident signals on confocal, orthogonal receivers, were equally sensitive and were used to interrogate the renal collecting system (urine) and the kidney parenchyma (tissue). Cavitation was detected in urine immediately upon SW administration in urine or urine plus X-ray contrast agent, but in tissue, cavitation required hundreds of SWs to initiate. Localization of cavitation was confirmed by fluoroscopy, sonography, and by thermally marking the kidney using the PCD receivers as high intensity focused ultrasound sources. Cavitation collapse times in tissue and native urine were about the same but less than in urine after injection of X-ray contrast agent. Cavitation, especially in the urine space, was observed to evolve from a sparse field to a dense field with strong acoustic collapse emissions to a very dense field that no longer produced detectable collapse. The finding that cavitation occurs in kidney tissue is a critical step toward determining the mechanisms of tissue injury in SWL. [Work sup ported by NIH (DK43881, DK55674, FIRCA), ONRIFO, CRDF and NSBRI SMS00203.]
Manipulating the pulse rate and resonance scale in speech and animal calls
Authors: Kawahara Hideki
Published: October 2013

A large proportion of the sound in speech and animal calls is voiced, and thus, periodic in nature. The sounds are generated by repetitive pulsive stimulations and each pulse produces a resonant response. This repetitive structure in the sounds can be interpreted as a time-frequency sampling process that provides a stream of information about the size, shape, and structure of the resonators in the vocal tract. This perspective has enabled us to develop a system, referred to as STRAIGHT, that can analyze, manipulate, and resynthesize vocal sounds. It is based on an extended pitch synchronous spectral estimation algorithm that recovers the underlying smooth time-frequency representation representing physical information on resonators. Ideally, this process removes stimulation related structure from the time-frequency representation, and thus, it should follow the same scaling laws as the physical dimensions of the resonating body. One problem is that speech sometimes contains multiple stimulations within one pitch period. This type of stimulation introduces a spectral deformation that has the same scaling laws as for the fundamental frequency (reciprocal of the repetition rate). The effects of this dual scaling and the problems of joint normalization will be discussed. [Work supported by MEXT Japan.]
Phonological systems of pediatric cochlear implant users: The acquisition of voicing
Authors: Chin Steven B. , Oglesbee Eric N. , Kirk Andrew K. , Krug Joseph E.
Published: October 2013

Although cochlear implants are primarily auditory prostheses, they have also demonstrated their usefulness as aids to speech production and the acquisition of spoken language in children. This presentation reports on research currently being conducted at the Indiana University Medical Center on the development of phonological systems by children with five or more years of cochlear implant use in English-speaking environments. Characteristics of the feature [voice] will be examined in children with cochlear implants and in two comparison groups: adults with normal hearing and children with normal hearing. Specific aspects of voicing to be discussed include characteristic error patterns, phonetic implementation of the voicing contrast, and phonetic implementation of neutralization of the voicing contrast. Much of the evidence obtained thus far indicates that voicing acquisition in children with cochlear implants is not radically different from that of children with normal hearing. Many differences between the systems of children with cochlear implants and the ambient system thus appear to reflect the children’s age as much as their hearing status. [Work supported by grants from the National Institutes of Health to Indiana University: R01DC005594 and R03DC003852.]
Alaskan river environmental acoustics
Authors: Dahl Peter H. , Pfisterer Carl , Geiger Harold J.
Published: October 2013

Sonars are used by the Alaska Department of Fish and Game (ADF&G) to obtain daily and hourly estimates of at least four species of migratory salmon during their seasonal migration which lasts from June to beginning of September. Suspended sediments associated with a river’s sediment load is an important issue for ADF&G’s sonar operations. Acoustically, the suspended sediments are a source of both volume reverberation and excess attenuation beyond that expected in fresh water. Each can impact daily protocols for fish enumeration via sonar. In this talk, results from an environmental acoustic study conducted in the Kenai River (June 1999) using 420 kHz and 200 kHz side looking sonars, and in the Yukon River (July 2001) using a 120 kHz side looking sonar, are discussed. Estimates of the volume scattering coefficient and attenuation are related to total suspended sediments. The relative impact of bubble scattering and sediment scattering is also discussed.
Modeling coherent Doppler sonar in fisheries acoustics
Authors: Tollefsen Cristina D. S. , Zedel Len
Published: October 2013

A computer model was developed to simulate the operation of a 250-kHz coherent Doppler sonar used to detect fish movements. The backscattered signal was constructed by summing contributions from many point targets. That signal was then detected and analyzed using the same method as used in the actual Doppler system. The model results reproduce predictions for the standard deviation of Doppler velocity estimates from volume backscatter based on the standard theoretical model of coherent pulse processing [Zrnic, IEEE Trans. Aerosp. Electron. Syst. AES-13, 344–354 (1977)]. However when the signal is modified to simulate the backscatter from a swimming fish (a single strong target among many weaker targets) the modeled standard deviation is 2 to 4 times lower than predicted by theory. Furthermore, the unusually low modeled standard deviations agree with laboratory and field observations. The model results confirm that the theoretical treatment used to predict the performance of Doppler measurements of current flow, blood flow, and atmospheric phenomena does not apply to the backscatter resulting from a single strong target such as a fish.