bluuebunny/crossref_metadata_2025 huggingface dataset:
Auditory informational masking and the Ear Club connection
Authors: Lutfi Robert
Published: November 2013

Erv Hafter has always made a special effort to promote recognition of young researchers in our field. His Ear Club of 40-plus years has provided a conversant audience for new investigators to test new ideas and his attendant hospitality has helped forge relationships valued throughout one’s career. In this talk, I will describe how my own work benefited from visits with Erv. The focus is on informational masking (IM). I will present recent work suggesting a strong connection between two major, but seemingly unrelated, factors associated with IM: masker uncertainty and target-masker similarity. Experiments involving multitone pattern discrimination, multi-talker word recognition, sound-source identification, and sound localization are described. In each case, standard manipulations of masker uncertainty and target-masker similarity (including the covariation of target-masker frequencies) are found to have the same effect on performance provided they produce the same change in the information divergence of target and masker, a measure of statistical separation between signals from information theory. The results seem to reflect a general perceptual principle that segregates signals based on differences in their statistical structure. Future plans are to test the generality of this result in a simulated-cocktail-party environment [Hafter et al. Intl. Symp. Hearing, in press].
Temporal effects when localizing targets defined by spatial consistency: Relation to Hafter’s work on “binaural adaptation”
Authors: Gilkey Robert H. , Simpson Brian D. , Thompson Eric R. , Iyer Nandini , Romigh Grffin
Published: November 2013

Simpson et al. [Proceedings of Meetings on Acoustics 19, 050140 (2013)] measured localization accuracy for sequences of noise bursts masked by simultaneous sequences of noise burst maskers (1 or 2). Targets were distinguishable from the maskers only in that all bursts within a target sequence arose from the same location, whereas each burst in a masker sequence arose from a different, randomly selected location. In this task, the spatial information extracted from each burst both helps define which element is the target (“target identification”) and where that target is located (“target localization”). Presumably, the listener is more focused on target identification early in the sequence and on target localization later in the sequence. And so, it is not surprising that localization accuracy increases dramatically as the length of the sequences is increased. This talk will compare these results to the foundational work of Hafter and his colleagues [e.g., Hafter, 1997, in Binaural and Spatial Hearing in Real and Virtual Environments, edited by R. H. Gilkey and T. R. Anderson (Erlbaum, Mahwah, NJ), pp. 211–232] investigating changes in the ability to extract binaural information during temporal sequences of sounds.
Feedback-driven corrective movements in speech in the absence of altered feedback
Authors: Niziolek Caroline A. , Nagarajan Srikantan S. , Houde John F.
Published: November 2013

Altered auditory feedback often evokes a compensatory vocal response in speakers, providing evidence that errors in speech production can be rapidly corrected online. To assess whether the same compensatory mechanism is employed in natural, unaltered speech, we carried out an acoustic analysis characterizing formant movement during single speaking trials. Subjects produced 200 repetitions each of three different monosyllabic words in the MEG scanner and, separately, in the presence of varying background noise levels. To assess corrective responses, we compared the centricity of formant values at the beginning to that at the middle of each trial. In all subjects, we found strong evidence of vowel “centering”—that is, a corrective movement mid-utterance that caused utterances at the periphery to move closer to the center of the formant distribution. Across subjects, the magnitude of vowel centering was correlated with auditory cortical suppression preceding the corrective movement, suggesting that the suppression may serve as a neural mechanism for error detection and correction. These findings suggest that less-prototypical utterances, which make up a large proportion of natural speech, are processed as potential errors, and that feedback-driven speech error correction is occurring constantly on a small scale.
Gradiency vs categoricity in the production of prosodic boundaries as reflected in different kinematic measures
Authors: Krivokapic Jelena , Mooshammer Christine , Tiede Mark
Published: November 2013

Two questions are examined in an EMA experiment: (1) are speech gestures at prosodic boundaries produced in a categorical or in a gradient manner (extending work by Krivokapic, Mooshammer, and Tiede 2013), and (2) how do different articulatory measures reflect boundary strength. Forty-eight sentences were constructed, each containing one, two, or three prosodic boundaries, for a total of 56 boundaries per sentence set. The range of predicted boundary types varied from a weak clitic boundary to a strong sentence boundary. Each boundary fell between the words “column and.” Seven subjects read six to eight repetitions of these sentences. Various temporal properties of boundaries have been examined, including the duration of the lip opening movement for [m], which is the movement closest to the boundary (and therefore most strongly reflects the boundary properties), and the duration of the jaw movement from the opening movement for the first vowel in “column” to the opening movement for the postboundary vowel (a variable which spans the boundary). These measures have been subjected to Gaussian mixture model analysis. Results show evidence for a more fine-grained structure than can be predicted by the three prosodic levels of traditional models. [Work supported by NIH DC003172-16, DC008780, DC002717].
Vowel locus equations as a measure of vowel coarticulatory aggressiveness
Authors: Chen Wei-rong , Iskarous Khalil
Published: November 2013

Studies in locus equations, a quantification of the degree to which F2 at vowel onset (or consonant place) can be predicted by F2 at vowel midpoint (or vowel place), have shown that the slope of locus equations is a reverse measure of coarticulatory resistance of consonants, in consonant-vowel (CV) sequences with C fixed and V varying. This study presents the first application of locus equations to the measure of coarticulatory properties of vowels. The locus equations analysis for vowels, on our articulatory data (collected with electromagnetic articulograph, EMA) of CV syllables from 7 Taiwan Mandarin speakers, with V fixed and C varying, shows that vowel /i/ has the greatest slope among vowels at tongue body, whereas vowel /a/ and /u/ mostly do not distinguish from each other, and at the tongue tip, the slope does not vary across the three vowels /i/, /a/ and /u/. Based on the CV model theory of gestural coordination (C-V in-phase relation) and the formula of linear regression, we claim that the slope of vowel locus equations is positively related to coarticulatory aggressiveness of vowel, which is further supported by a comparison with a well-established measure of vowel coarticulatory aggressive, based on contextual variability, on the same data.
An MRI comparison of /s/ production in four subject conditions
Authors: Pedersen Andrew D. , Hwang Jun , Woo Jonghye , Xing Fangxu , Prince Jerry L. , Stone Maureen
Published: November 2013

This study examined a control subject and three patients who had surgery to remove tongue cancer. One patient’s surgery was closed with sutures, one with a radial forearm free flap reconstruction, and one with sutures plus radiation. This study aims to ascertain the effects of these traumas on internal and surface tongue motion during speech. The flap consists of soft tissue that is vascularized, but not innervated; it increases tongue bulk, but has no direct motor control. The other two patients have missing tissue and a scar where the cut regions were sewn together. This morphological change may increase difficulty creating properly formed palatal contacts. The supplemental radiation treatment may cause additional muscle stiffness due to fibrosis. The cine and tagged datasets were recorded in axial, coronal, and sagittal orientations using identical parameters so their data could be overlaid. Each dataset was reconstructed into 3D volumes, one for each time-frame in the word. From each cine-MRI volume, the 3D tongue surface was segmented and used as a “mask” in the tagged-MRI volume. Inthe tagged-MRI volumes, 3D displacement fields were calculated to show motion of each tissue point inside the tongue mask during the speech task.
Detection performance of coprime sensor arrays
Authors: Adhikari Kaushallya , Buck John R.
Published: November 2013

Coprime sensor arrays (CSAs) achieve the resolution of a fully populated uniform linear array (ULA) with the same aperture using fewer sensors. The CSA's reduced number of sensors diminishes its ability to attenuate white noise, and consequently also reduces its array gain. Assuming narrowband independent signal and white noise, when the signal and the noise are modeled by circular complex zero mean Gaussian distributions, the detection statistic distribution for the ULA simplifies to an exponential distribution with its parameter dependent on the input SNR. The detection statistic for the CSA is the product of the output of one subarray with the complex conjugate of the output of the second subarray. Being the product of two independent complex Gaussian random variables, the CSA detection statistic has a distribution proportional to a modified zeroth order Bessel function of the second kind [O'Donoughue and Moura, IEEE Signal Process. (2012)]. Manipulating the ULA and CSA detection statistic distributions provides analytical expressions for probabilities of detection and false alarm and also mean discriminating information. Evaluating these expressions confirms that a CSA pays a detection gain penalty of about 5 dB over a wide range of SNRs and array sizes. [Work supported by ONR.]
Coprime microphone arrays for direction-of-arrival estimation
Authors: Nichols John P. , Xiang Ning
Published: November 2013

Direction-of-arrival estimation using microphone arrays is relatively simple with low signal-to-noise ratio, but precise location estimation amongst noise requires many sensors to reduce beam width. Coprime linear microphone arrays allow for narrow beams with fewer sensors. A coprime microphone array is made up of two overlapping uniform linear arrays with M and N sensors, where M and N are coprime. By applying spatial filtering with both arrays and combining their outputs, M + N sensors can yield MN directional bands. In this work, a coprime microphone array is used to estimate the location of multiple uncorrelated narrowband sources hidden in noise.
Warren Blazier—The consultant's consultant
Authors: Talaske Richard
Published: November 2013

Many acoustic consultants turned to Warren for advice or confirmation of design solutions to solve their toughest noise control design challenges, this consultant included. Spanning nearly three decades, Warren collaborated with TALASKE | Sound Thinking technically as Associated Acoustical Consultant on retainer and business-wise as a member of the Board of Directors. Insights into the expertise and personality of Warren will be provided, with added contributions by Jerry Hyde.
Deep roots and spreading branches—A shared legacy of acoustic DNA
Authors: Kirkegaard Larry , Auerbach Len
Published: November 2013

Ron McKay and Warren Blazier were part of a generation of strong would-be consultants that were drawn to Bolt Beranek and Newman in the early to mid-sixties. They brought with them broad skills, great curiosity, and a contagious spirit of collaboration. Harvard and MIT were prime sources of talent, but BBN was magnetic to talent as well as project work from around the world. To know and appreciate Ron and Warren, you must know the richness of talent that surrounded and influenced them—their professional companions. Imagine a lively discussion with input from the likes of Leo Beranek, Dick Bolt, Bob Newman, Bill Cavanaugh, Ted Schultz, David Klepper, Bill Watters, Rein Pirn, George Kamperman, Bob Hoover, Carl Rosenberg, Layman Miller, Jacek Figwer, Jack Curtis, Russell Johnson, Bob Wolff, Tom DeGaetani, Len Auerbach, Dennis Paoletti, Joel Lewitz, and Dave Conant among many others. Arm-to-arm they could reach around the world. Their legacies enrich our profession in a myriad of ways. This paper shares memories and insights into both the genius and humanness of an important generation of our colleagues.
Patterns in bioacoustic activity observed in U. S. National Parks
Authors: McKenna Megan F. , Mennitt Dan J. , Lynch Emma , Joyce Damon , Fristrup Kurt M.
Published: November 2013

The Natural Sounds and Night Skies Division of the U.S. National Park Service has collected month-long acoustic recordings at more than 300 sites in 73 park units located throughout the United States, dating back to 2000. Each monitoring session lasted 25 days or more; some sites were monitored more than once. At all sites a calibrated Sound Level Meter recorded acoustic data in one-second, one-third octave band resolution; at many sites, simultaneous continuous acoustic recordings were collected using a digital audio recorder. These data were analyzed to identify broad patterns in bioacoustic activity within one-third octave bands. These bioacoustical patterns were analyzed in relation to site characteristics, seasons, and anthropogenic noise levels to identify significant associations. The resultant model could be used to produce a map predicting bioacoustical activity throughout the coterminous United States.
Quantifying ocean noise and its spatiotemporal variability on Australia’s Northwest Shelf
Authors: Erbe Christine , Gavrilov Alexander , McCauley Robert
Published: November 2013

The Northwest Shelf is an extensive oil and gas region off Western Australia. The Centre for Marine Science and Technology at Curtin University has recorded underwater noise in this region for 14 years on behalf of industry and government. Under the Collaborative Environmental Research Initiative (CERI), this data is being shared and synthesized to quantify the marine soundscape and to describe spatiotemporal variability. Automatic software analysis tools were developed to process the data. Power spectrum density percentiles were computed for all sites on a monthly basis, and compared. Distinct spectral features were identified. Factors contributing to the observed spatiotemporal variability ranged from long-term offshore oil and gas installations to fish choruses. [Work supported by Chevron Australia.]
Ocean wave seismic and acoustic noise detected with distributed fiber optic sensor array
Authors: Hathaway Kent K. , Costley Richard D. , Smith Eric , Milburn Troy , Picucci Jennifer R.
Published: November 2013

The U.S. Army Engineer Research & Development Center installed a Fiber Optic Sensor System (FOSS) at the Field Research Facility (FRF) in Duck, NC as a test-bed for evaluating FOSS performance in measuring ambient acoustic and seismic noise in a coastal environment. The sensor system consists of a buried fiber optic cable with a length of approximately 3 km, which wends its way through the sand dunes and along the beach. An optical interrogator contains a pulsed laser which injects light into an optical fiber within the cable and receives Rayleigh backscattered signals from it. The system, which is able to detect and locate seismic activity along the entire length with a 10 m resolution, is being used to study ocean wave generated noise. The FRF also maintains and operates a real-time cross-shore directional wave array, consisting of five bottom-mounted acoustic wave gauges installed at 2 to 11 m depths. The main focus of the work presented here compares FOSS data with directional wave measurements made with the cross-shore array under a variety of conditions. Data collected with other sensor systems (e.g., vertical long-period seismometer, infrasound microphone, anemometers, rain gauges, high resolution video) were also used in this comparison.
Pulsed focused ultrasound treatment of muscle mitigates paralysis-induced bone loss in the adjacent bone: A study in a mouse model
Authors: Poliachik Sandra L. , Khokhlova Tatiana D. , Wang Yak-Nam , Simon Julianna C. , Gross Ted S. , Bailey Michael R.
Published: November 2013

Bone loss can occur following bed rest, space flight, spinal cord injury, or age-related hormonal changes. The treatment methods for this condition include pharmaceutical interventions and exercise, neither of which is particularly effective. Other technologies include low intensity pulsed ultrasound targeted to the bone, used previously to enhance fracture healing, and whole body vibration. This study attempted to mitigate paralysis-induced bone loss indirectly, by applying pulsed focused ultrasound (pFUS) to the midbelly of a paralyzed muscle. We employed a mouse model of disuse that utilizes onabotulinumtoxin A, which induces rapid bone loss in 5 days. The pFUS treatments were performed daily for four consecutive days following paralysis. A spherically focused 2-MHz transducer produced 5-microsecond pulses at pulse repetition frequency mimicking motor neuron firing rates during walking (80 Hz) or standing (20 Hz). Two different power levels were used corresponding to peak positive focal pressures of 30 and 18 MPa. The trabecular bone changes were characterized using micro computed tomography. Our results indicated that application of pFUS at pulse repetition frequency of 20 Hz and lower amplitude setting successfully mitigated paralysis-induced bone loss. The targeted muscle tissue did not display any sign of injury. [Work supported by CDMRP SCIRP (SC090510).]
High intensity focused ultrasound ablation of ethanol-treated liver tissues and cancer cells
Authors: Hoang Nguyen H. , Murad Hakm Y. , Ratnayaka Sithira H. , Chen Chong , Khismatullin Damir B.
Published: November 2013

We have investigated the combined effect of HIFU and ethanol injection on the temperature rise and cavitation in porcine liver tissues and on the viability and proliferation rate of HepG2 liver cancer cells. Tissues were injected with 95% ethanol before being subjected to the HIFU beam generated by a 1.1 MHz transducer with acoustic power ranged from 1.17 W to 20.52 W. Cavitation events and the temperature in and around the focal zone were measured by a passive cavitation detector and type K thermocouples, respectively. In the cell study, 100 μl of HepG2 cell suspension (2.7 million cells/ml) was placed in a 0.2 ml thin-wall PCR tube. Ethanol 2% or 4% in the cell growth medium was added to the cell suspension, and the cells were then exposed to HIFU for 30 s. The data of these experiments show that the pre-treatment of tissues with ethanol reduces the threshold power for inertial cavitation and increases the temperature rise. Both the viability and proliferation rate were significantly decreased in cells treated with ethanol and HIFU, as compared to individual treatments. The results of our study indicate that ethanol injection and HIFU have a synergistic effect on liver cancer ablation.
Prediction of the spatial response of a microphone capsule using scattering and lumped-element simulations
Authors: Rollow Douglas , Gorelik Vladimir , Wulkau Meike , Chafe Sebastian
Published: November 2013

When a microphone capsule is placed in an environment with surrounding structures, the electrical response of the capsule will be dictated by the capsule design and by acoustic scattering of the structures surrounding it. Lumped element models of the transducer are typically used in predicting the electrical response to the field, but when the transducer is operating at a frequency where the spatial variation of the field is significant, the simplifying assumptions used in these models no longer hold. In this work, a finite element-based scattering simulation provides blocked-port field quantities to drive a lumped element circuit model, predicting the electrical output as a function of the frequency and incident angle of an incoming plane wave. The scattering simulation allows for the inclusion of mechanical supporting structures and protective screens, and their influence on the field at the rear port of a gradient transducer. Simulated results are shown for the simplified capsule and compared to measurements of a real capsule in free field conditions as well as with surrounding structures.
Characterization of the mechanical properties of the steelpan
Authors: Bryan April , Gobin Marc , Griffith Akill , Frederick Dillon , Copeland Brian , Imbert Clement
Published: November 2013

The steelpan is a struck idiophone whose playing surface is constructed by forming the top of a fifty-five gallon steel oil drum into a sunken, nearly hemispherical surface and then raising smaller shells on the hemisphere to form notes. The completed instrument resembles an inverted turtle shell and is played by striking the notes with sticks. Although it is understood that variations in note geometry and material properties are mainly responsible for the characteristic sounds generated when the notes are struck, few studies have investigated these relationships. Previous research efforts have explored the metallurgical properties and the characteristic vibrations of the notes. Less emphasis has been placed on the relationship between the mechanical properties of the steelpan and its acoustic behavior. In this research, the variation in the mechanical properties across the playing surface of a tenor steelpan is characterized. Of the instruments in the steelpan family, this instrument has the greatest deformation and the most notes. More specifically, the variation in the residual stress, strength, Young’s Modulus, and Poisson’s ratio are determined and compared among octave sets. This characterization is important for the development of models that relate the mechanical properties to the acoustical behavior of the steelpan.
Percussion, via transducers
Authors: Case Alex
Published: November 2013

The sounds within a music recording are necessarily mediated by the microphones and loudspeakers associated with their recording and playback. The effect of microphones—type and placement—invites a unique view of musical acoustics. The necessity of loudspeaker playback motivates a range of signal processing strategies, using equalization, compression, reverberation, distortion, and more to further reshape the sound. This paper reviews the sonic influence of contemporary audio engineering craft on the sound of percussion instruments as realized in music recordings.
A perceptually motivated active noise cancellation system for hearing impaired listeners: An overview
Authors: Xu Buye , Xiao Jinjun , Zhang Tao
Published: November 2013

Nowadays most hearing impaired (HI) patients are fitted with either open-fitting or vented-fitting hearing aids (HAs) to reduce the occlusion effect. In an environment where strong low-frequency ambient noise is present, significant noise energy can directly leak into the ear canal bypassing noise reduction algorithms in the HAs and may reduce speech intelligibility and listening comfort for HA users. One way to mitigate such an issue without occluding the ear canal is to implement an active noise cancellation (ANC) system inside the ear canal. Traditional ANC systems are designed to minimize the total sound pressure level in the ear canal. However, this may not necessarily lead to an optimal solution from the perceptual perspective (e.g., loudness may be reduced instead of being minimized as a result). In this paper, a perceptually motivated feedback ANC system is presented: a spectral shaping filter is applied to the residual error signal to minimize the loudness for HI listeners. In addition, implications of the practical constraints introduced by the HAs are discussed based on acoustic simulations and experimental results.
Local and global active noise control using a parametric array loudspeaker
Authors: Tanaka Nobuo
Published: November 2013

This paper deals with local as well as global active noise control (ANC) using a parametric array loudspeaker (PAL) possessing intriguing properties: sharp directivity, low sound pressure decay by distance, capability of steering directivity, etc. After briefing some properties of a PAL necessary for ANC, this paper presents pinpoint control using a PAL for suppressing the sound pressure at a designated location, hence local control. It is shown that unlike conventional ANC in which a voice coil loudspeaker is used, the pinpoint control may achieve the sound pressure suppression without causing spillover. Using the same sound control source, PAL, this paper then refers to global control, termed trivial control in the art, enabling one to generate a global zone of quiet. The trivial control strategy falls into a category of acoustic power control based on a trivial condition requiring the collocation of a primary source and a control source. The trivial condition formerly avoided because of literally trivial may be implemented due to the property of a PAL, thereby enhancing the control effect, theoretically infinity. Two kinds of control strategy are then demonstrated with a view to fulfilling the trivial condition for global control.
Virtual mechanical impedance approach for the active structural acoustic control of panels
Authors: Berry Alain , Michau Marc , Micheau Philippe , Herzog Philippe
Published: November 2013

This work investigates harmonic Active Structural Acoustic Control of flexural panels using structural, collocated and dual actuator-sensor pairs. Two types of transducer technologies are envisioned: (1) thin piezoelectric actuators and sensors; (2) electrodynamic inertial actuators and transverse velocity sensors. The control strategy is to locally impose a complex, virtual mechanical impedance to the structure via a linear relation between the actuator input and sensor output of each pair, at each frequency of interest. This virtual impedance is optimized to minimize the sound radiation of the structure at the corresponding frequency. The approach is implemented as a two-step process: (1) the optimal virtual impedance matrix is derived from identification of the primary sound and transfer functions between the control actuators, structural sensors and far-field acoustic sensors; (2) the optimal virtual impedance matrix is imposed using a real-time, iterative controller. Numerical and experimental results are discussed to highlight the underlying physical interpretation of the virtual impedances for sound radiation or sound transmission control. The implication of the different actuator and sensor technologies in terms of sensing the global vibration and acoustic response is also discussed.
Development of radiation mode shapes for cylindrical shells
Authors: Aslani Pegah , Sommerfeldt Scott , Blotter Jonathan
Published: November 2013

For many acoustical applications, it is desirable to evaluate the radiated power. About two decades ago, a set of formulations were developed to represent the acoustic radiation in terms of radiation mode shapes. A convenient method for determining these radiation modes involves representing the radiating structure as a set of elementary simple radiators, from which the radiation can be decomposed into the set of orthogonal radiation modes. Radiation mode shapes are very useful not only for calculating the power, but also to determine which modes are the most efficient radiators. This generally allows one to achieve a rather accurate estimate of the radiated power by including only a relatively small number of the most efficient radiating modes. This concept has significant implications for an efficient strategy for implementing an active noise control system. Previous work reported in the literature has primarily focused on evaluating the radiation mode shapes of flat structures, such as beams and plates. There has not been as much reported on the radiation mode shapes for cylindrical shells. This paper focuses on implementing these concepts to determine the radiation mode shapes of cylindrical shells and using them to determine the radiated acoustic power.
Pneumatic infrasound source: Model experiment and theory
Authors: Gorhum Justin D. , Muir Thomas G. , Slack III Charles M. , Hawkins Timothy W. , Ilinskii Yurii A. , Hamilton Mark F.
Published: November 2013

In a previous presentation [J. Acoust. Soc. Am. 133, 3327 (2013)], an experimental model study of a pneumatic infrasound source that utilizes the pulsation of compressed air was discussed. The present paper discusses new measurements and theoretical modeling efforts that are currently underway. Measurements of the source level, directivity patterns, propagation loss, and frequency response are presented and analyzed. Acoustic and aerodynamic models are presented and discussed with a focus on modeling and predicting nearfield system performance using multipole (monopole, dipole, and quadrupole) representations of the sound source. Measurement techniques and engineering considerations are addressed, as are physical interpretations of the process. [Work supported by ARL:UT Austin.]
Within- and across-channel integration of information for the precedence effect
Authors: Seeber Bernhard U.
Published: November 2013

Erv Hafter has with his team investigated the spectral and temporal integration of binaural information to learn about binaural hearing in situations with multiple sounds and reflections. For these studies, the Simulated Open Field Environment (SOFE), a loudspeaker setup in an anechoic chamber, was created. Beginning with an overview of the SOFE, I will present results on the spectral density and bandwidth of long-duration complex tones needed for the precedence effect to occur, the ability to correctly locate a sound in the presence its delayed copy. The hypothesis is that the precedence effect cannot be evoked with a single low frequency tone, because the addition of its delayed copy alters the interaural phase and thus its location. A larger bandwidth is needed to stabilize localization at the lead either through integrating binaural information across frequency or through extracting information from the temporal envelope. Results show that a stable precedence effect could not be obtained at or below 1 Bark bandwidth, and that at least two tones per critical band over 2 Bark are required. The echo threshold increases with increasing bandwidth or spectral density, suggesting that within and across-channel information is combined.
A hybrid numerical model for the exterior-to-interior transmission of impulsive sound through three-dimensional, thin-walled elastic structures
Authors: Remillieux Marcel C. , Pasareanu Stephanie M. , Svensson U. Peter
Published: November 2013

Exterior propagation of impulsive sound and its transmission through three-dimensional, thin-walled elastic structures, into enclosed cavities, are investigated numerically in the framework of linear dynamics. A hybrid model was developed in the time domain by combining the advantages of two existing numerical tools: (i) exterior sound propagation and induced structural (façade) loading are computed using the image-source method for the reflected field (specular reflections) combined with an extension of the Biot-Tolstoy-Medwin method for the diffracted field, (ii) the fully coupled vibro-acoustic response of the interior fluid-structure system is computed using a truncated modal-decomposition approach. In the model for exterior sound propagation, it is assumed that all surfaces are acoustically rigid. Since coupling between the structure and the exterior fluid is not enforced, the model is applicable to the case of a light exterior fluid and arbitrary interior fluid(s). The structural modes are computed with the finite element method using shell elements. Acoustic modes are computed analytically assuming acoustically rigid boundaries and rectangular geometries of the enclosed cavities. This model is verified against finite-element solutions computed with a commercial software package for the cases of rectangular structures containing one and two cavities, respectively.
A study on structural vibration of washing machine with gyroscope
Authors: Na Gyu Sung , Park Young Jin , Park Yoon Sik , Kang Jeong Hoon
Published: November 2013

This paper is proposed about reducing the transient vibration of drum type washing machine. The vibration of washing machine is caused by unbalanced cloths in high spinning drum, and the displacement of tub is maximized at transient range about 3 Hz (180 rpm). The dynamic model of washing machine is include a diaphragm. In this study, the displacement of tub is decreased by using gyroscope system. Multibody dynamic model ofwashing machine include gyroscope is designed and the vibration of tub have been reduced by the gyroscope system.
Phonological encoding and articulatory duration in spontaneous speech
Authors: Fricke Melinda
Published: November 2013

Many studies have found that word duration is correlated with a word’s contextual predictability in conversational speech. Lindblom (1990)’s Hypo/Hyperarticulation Theory, Jurafsky et al. (2001)’s Probabilistic Reduction Hypothesis, and Aylett and Turk (2006)’s Smooth Signal Redundancy Hypothesis all suggest that such differences in duration are due to processes occurring primarily at the lexical level. The present study, however, suggests that these differences may be attributable to processes occurring at the phonological level. In this study, mixed modeling is used to examine the voice onset time and rime duration of monosyllabic /p t k/ words in spontaneous, connected speech (the Buckeye Corpus; Pitt et al., 2007). Higher contextual predictability given the previous word is found to be associated with shorter VOT, while higher contextual predictability given the following word is associated with shorter rime duration. VOT also varies according to the number and type of a word’s phonological neighbors; words with more neighbors overlapping in the rime have significantly longer VOT, while words with more neighbors overlapping in the initial CV have significantly shorter VOT. These results motivate a model of speech production that assumes both lexical-phonological feedback and positional encoding of segments (e.g., Sevald and Dell, 1994).
The effect of task difficulty on phonetic convergence
Authors: Abel Jennifer
Published: November 2013

Cognitive workload is the information processing load a person experiences when performing a task; the more difficult the task, the greater the cognitive workload. Increased task difficulty/cognitive workload has been shown to have an effect on several acoustic measures of speech such as amplitude, word/syllable/utterance duration, and f0. To date, the task difficulty-speech production link has only been studied in individuals. This study examines the effect of different levels of task difficulty on phonetic convergence within dyads collaborating on a task. Dyad members had to build identical LEGO® constructions without being able to see each other’s construction, and with each member having half of the picture-based instructions required to complete the construction. Three levels of task difficulty were created, based on the number of pieces in each step of the construction—easy (2 pieces/step), medium (3 pieces/step), and hard (4 pieces/step)—with five dyads at each level (30 participants total). Dyads were audio- and video-recorded, and completed working memory and mental rotation tests and personality questionnaires prior to the task. Acoustic analysis and AXB perception studies are underway to examine the amount and type of convergence in each dyad.
Temporal coordination of sibilants in Polish onset clusters
Authors: Pastätter Manfred , Pouplier Marianne
Published: November 2013

In this study we employ the gestural syllable model to examine cluster-vowel timing in Polish sibilant initial (SI = {/∫m-, ∫p-, sp-, sk-/}) and sibilant final (SF = {/m∫-, p∫-, ps-, ks-/}) onset clusters. In this model, the timing of a complex onset is evaluated relative to a simplex onset and it is predicted that timing relations between onset and vowel should be invariant independently of onset complexity (Browman and Goldstein, 2000). Articulatory data of three speakers show that SI clusters conform to the predicted timing pattern in terms of a globally organized onset cluster relative to the vowel (“c-center”). This is compatible with previous findings for several languages. For SF clusters, however, there are considerable timing differences between complex and corresponding simplex onsets. This suggests that SF clusters are coordinated differently (and inconsistently) to the following vowel compared to SI clusters, as also reported previously for Romanian (Marin, 2013). We investigate to which extent this difference between SI and SF clusters is related to sibilants’ high coarticulatory resistance preventing a close C-V coordination. We will present an analysis of jaw movement data to consider possible effects of jaw position constraints on the temporal coordination of clusters.
A computer assisted pronunciation training system
Authors: Cho Kwansun , Harris John G.
Published: November 2013

A computer assisted pronunciation training (CAPT) system is implemented for native Korean speakers who are learning American English. The CAPT system is designed to help a Korean adult learner improve his/her production and perception of American English front vowels (/i, I, ɛ, æ/) since these vowels are the most difficult for Korean learners due to the different phonetic systems of the two languages. The CAPT system provides a learner a learning session mimicking a live interaction between teacher and student as well as a practice session triggering a learner’s interest in continued practice. Pedagogically meaningful activities such as listen-and-repeat, minimal-pair-comparison, target-sound-isolation, and record-and-play are utilized in the learning session. During the learning session, the CAPT system analyzes a monosyllabic word including one of the target front vowels spoken by a learner and gives instantaneous personalized feedback. During the practice session, the CAPT system provides real-time games that are fun but also provide the necessary perception and articulation practice.
Measurable acoustic variants as predictors of progress in speech therapy
Authors: Siren Kathleen
Published: November 2013

Despite the availability of free, user-friendly acoustic analysis programs, acoustic documentation of speech sound change during speech therapy is rarely mentioned in speech research literature. Thus, the utility of acoustic analysis to document speech change over time in children with speech errors is unknown. A prior study documented children’s /s/ productions as they progressed through speech therapy and compared spectrographic analysis of productions to clinicians’ perceptual judgments of accuracy. Results indicated a greater number of /s/ productions were judged accurate based on visual (acoustic) analysis vs auditory (perceptual) judgment for all clients, particularly during a period of time when clients’ /s/ productions were becoming more frequently accurate. The purpose of this current investigation is to identify the measurable acoustic features of /s/ production that indicate when an individual’s /s/ production is improving even when the productions are still heard as incorrect. By comparing productions identified as correct visually but incorrect auditorily to productions identified the same both visually and auditorily, this study identifies acoustic variants that are indicative of subtle improvements in production not yet identifiable by adult listeners. These subtle, yet measurable, acoustic characteristics may identify potential acoustic markers for sound maturation in children’s disordered speech production.
Assessment of head reference placement methods for optical head-movement correction of ultrasound imaging in speech production
Authors: Roon Kevin , Jackson Eric , Nam Hosung , Tiede Mark , Whalen Doug H.
Published: November 2013

One method of quantification of tongue movement using ultrasound imaging during speech production requires determination of tongue position relative to the palate, corrected for probe and head motion so that successive frames can be meaningfully compared. This method involves placing infrared emitting diodes (IREDs) on a “tiara” attached to the participant’s head (Whalen et al., 2005). An alternative is to attach IREDs directly to the participant’s skin. In either case, the IREDs can potentially move relative to the participant’s skull. The present study examined movement with both methods for simple utterances, a read paragraph, and spontaneous speech. The amount of IRED movement observed using both methods allowed identification of regions where IREDs should be affixed on a participant’s skin to minimize movement when the direct application method is used. Results of simulations showing the effects of this IRED movement on the calculated head-movement correction of the tongue images are presented. Given the results of these simulations, guidelines are proposed for establishing thresholds that can be used to determine whether a given experimental trial should be included based on the amount of reference IRED movement. Differences in movement due to linguistic content or style will also be discussed.
Measurements of compressional wave dispersion and gradients in muddy sediments
Authors: Holland Charles W. , Dettmer Jan , Dosso Stan , Steininger Gavin
Published: November 2013

Cohesive or muddy sediments have received relatively sparse attention in the ocean acoustics community—this despite the fact that they form a non-negligible fraction of the sediments found in shallow water (roughly 25%) and by far the major sediment type in the deep ocean. Seabed reflection measurements have provided some understanding about the frequency dependence of the sound speed and attenuation in muddy sediments. The evidence is for weak dispersion from 300–200,000 Hz and an approximately linear dependence of attenuation on frequency from 300–3000 Hz. In addition, the measurements have yielded information on gradients. Surprisingly large near-surface density gradients exist that vary across the shelf. Given the large density gradients, the gradients in sound speed are curiously small, suggesting that the bulk modulus is nearly proportional to the density, at least in depth. Dispersion and gradient results are discussed for muddy sediments in various mid to outer shelf regions.
Inertial cavitation enhancement using confocal ultrasound
Authors: Fowler Robert A. , Lafond Maxime , Poizat Adrien , Mestas Jean-Louis , Chavrier Françoise , Béra Jean-Christophe , Lafon Cyril
Published: November 2013

Inertial cavitation has been shown to be useful in many therapeutic applications; thus, controlling this phenomenon is of great therapeutic interest. However, the stochastic nature of cavitation often proves problematic for predicting its location and extent. Traditional solutions to this problem are the of use dedicated detection apparatuses, or to use injectable microbubbles (MBs), which act as nuclei for the initiation of cavitation. We hypothesize here that cavitation can be reliably controlled without the use of MBs using a confocal system, which produces a lobular focal zone due to acoustic interference. This interference pattern was studied both in simulation and hydrophone measurement. Cavitation extent was confirmed chemometrically with an assay for hydroxyl radical formation, and by passive cavitation detection with a hydrophone. A high speed camera was used to image the initiation of cavitation within the focal zone, the evolution of the bubble cloud, and the subsequent bubble rebound after pulse cessation. The experiments in this work confirm that cavitation is produced more reliably in the confocal setup as opposed to a single transducer, as well as illuminating the mechanisms for this enhancement. [Work supported by the European Union through the Eurostars program (project E!6173) and Caviskills SAS.]
Validation of ultrasonic beam steering accuracy for medical applications by means of a modified Hough transform
Authors: Ploß Peter , Rupitsch Stefan J. , Lerch Reinhard
Published: November 2013

Medical applications such as ultrasonography depend on the excitation of ultrasound wave packets that propagate with a targeted orientation in the examined body. Nowadays, the wavefronts’ orientation is usually adjusted by the well-established electronic beam steering process, as compared to mechanical skewing of the ultrasound transducer. One sector scan (B-mode) is reconstructed from several A-mode acquisitions. This reconstruction process is dependent on the proper knowledge of the polar steering angles αk. From a clinical perspective, the correct reconstruction of the geometry is of great importance, since the detection of diseases (i.e., a tumor) is strongly dependent on the shape. We present a modified Hough transform that allows for analyzing acoustic pressure field distributions in order to precisely determine the direction of ultrasound propagation. The method is applicable to spatially discretized measurement and simulation data obtained either by hydrophone measurements or Finite Element Method simulations. Verification with artificial data confirmed an angular accuracy better 0.1°. This novel approach enables manufacturers of sonographic devices to verify the electronically chosen wavefront orientations by conducting measurements as well as simulations. The influence of parameters such as sampling rate, geometrical dimensions, material parameters, or apodization can be studied in a timesaving computer-aided engineering scheme.
Cyclic variation of three-dimensional geometry of the rat carotid artery bifurcation assessed by high-frequency ultrasound imaging
Authors: Jin Changzhu , Nam Kweon-Ho , Bok Tae-Hoon , Paeng Dong-Guk
Published: November 2013

The computational simulation of the interaction between blood flow and arterial wall motion during a cardiac cycle is complicated and requires high quality information of the vessel wall motion in space and time. In this study, a set of cross-sectional ultrasound images was acquired using an electrocardiogram-gated kilohertz visualization mode, which provides 1000 frame images per second, by an ultrasound imaging system (Vevo 770, VisualSonics, Canada) with a probe of 40-MHz central frequency (RMV 704). The three dimensional (3D) geometry of carotid artery bifurcation was reconstructed at systolic and diastolic phases during a cardiac cycle using the cross-sectional ultrasound images, and a block meshing method was applied to the reconstructed 3D geometry. Then, an appropriate hexahedral mesh was constructed for the computational simulation. The 3D geometry measured by high-frequency ultrasound imaging provides high temporal and spatial information on the vessel wall motion during a cardiac cycle, which is important for accurate computational simulation of hemodynamics in the bifurcation area of the carotid artery. The fluid-structure interaction simulation of blood flow in the carotid artery bifurcation during a cardiac cycle is in progress using the meshes of 3D geometry of vessel wall. [Work supported by NIPA-2013-H0401-13-1007 and 2013R1A1A2043478.]