bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic and photoacoustic imaging of spheroids
Authors: Kolios Michael C. , Berndl Elizabeth S. , Wirtzeld Lauren C. , Strohm Eric M. , Czarnota Gregory J.
Published: May 2013

Acoustic and photoacoustic high frequency imaging (50–100 MHz) can be used to generate images of cell constructs and spheroids with good spatial resolution and contrast. Here we demonstrate how co-registered acoustic and photoacoustic imaging can be used for imaging spheroids. Spheroids are widely used in cancer research and biology since they emulate a three-dimensional environment such as that experienced in tumors. Spheroids were made by the hanging-drop method using the MCF-7 cancer cell line. To generate photoacoustic contrast, MCF-7 cells were incubated with optical absorbing nanoparticles (e.g., gold nanorods, 780 nm absorption) for 24 h and mixed with native MCF-7 cells prior to spheroid formation. The spheroids were between 0.5 mm and 1mm in diameter. Imaging was performed with the VisualSonics VEVO 770 (25–55 MHz) and a high-resolution SASAM acoustic/photoacoustic microscope for frequencies over 80 MHz (Kibero GmbH, Germany). The spheroid was imaged first using pulse echo ultrasound, then with photoacoustics immediately after. The necrotic core of the spheroid had a 20 dB increase in ultrasound backscatter compared the viable cells surrounding the core, and the ultrasound/photoacoustic images of the spheroid were co-registered showing the distribution of the optical absorbing agents.
High-frame-rate retrospective imaging of mouse-embryo cardiac function using annular array and Doppler-derived gating
Authors: Ketterling Jeffrey A. , Filoux Erwan , Aristizabal Orlando , Mamou Jonathan
Published: May 2013

A high-frequency (HF) imaging system based on a custom 5-element, 40 MHz annular array has been used to study the cardiovascular development of mouse embryos. High-frame-rate imaging of the heart dynamics was achieved using a retrospective reconstruction method based on Doppler-derived electrocardiogram (ECG) waveforms and respiratory gating was used to suppress motion artifacts. The ECG signals were obtained by measuring blood-flow velocities in major arteries of in-vivo mouse embryos using a custom HF Doppler apparatus made from two 20 MHz, single-element, PZT transducers with a Doppler sample volume of 15 mm. Co-registered M-mode data were acquired from the annular array excited with a 5-channel pulser/receiver. A synthetic-focusing (SF) algorithm was used to improve spatial resolution (<100 µm), depth-of-field (>10 mm) and signal-to-noise ratio (>45 dB). This technique was used on embryos aged from 11.5 to 14.5 days and provided high-resolution, morphologically correct B-mode cine-loops of the heart chamber dynamics at frame rates of 1 kHz. The ultra-fine temporal resolution (1 ms) allowed for precise quantification of the mean cardiac cycle length and detailed visualization of fast events such as opening and closing of the mitral valve. The speckle characteristics of the high-resolution images could be used to assess blood flow and to quantify myocardial strain at each developmental stage of the embryonic heart.
Quantitative ultrasound evaluation of tumor cell death response in locally advanced breast cancer patients to chemotherapy treatment administration
Authors: Czarnota Gregory , Sadeghi-Naini Ali , Papanicolau Naum , Falou Omar , Dent Rebecca , Verma Sunil , Trudeau Maureen , Boileau Jean-Francois , Spayne Jacqueline , Iradji Sara , Sofroni Ervis , Lee Justin , Lemon-Wong Sharon , Yaffe Martin , Kolios Michael
Published: May 2013

A clinical study was undertaken investigating the efficacy of ultrasound to quantify cell death in tumor responses with cancer treatment. Patients (n = 25) with locally advanced breast cancer received anthracyline and taxane-based chemotherapy treatments over four to six months. The majority of patients went on to have a modified radical mastectomy and correlative whole mount histopathology. Data collection was carried out using an Ultrasonix-RP and an L15-5 6 cm transducer pulsed at 10 MHz with RF data collected five times during neoadjuvant chemotherapy. Data indicated increases of approximately 9 dBr (+/−1.67) maximally in ultrasound backscatter in patients who clinically responded to treatment. Patients assessed as responding poorly demonstrated significantly lower increases (2.3 +/− 1.7 dBr). Increases in 0-MHz intercept followed similar trends while increases in spectral slope were observed locally from tumor regions demonstrating increases in tissue echogenicity. This study demonstrates the potential of ultrasound to quantify changes in tumors in response to cancer treatment administration in a clinical setting. The results indicate that such responses can be detected early during a course of chemotherapy and should permit ineffective treatments to be changed to more efficacious ones potentially leading to improved treatment outcomes.
Radial shear strain elastography imaging of carotid atherosclerotic plaques in a porcine model
Authors: Cloutier Guy , Majdouline Younes , Garcia Damien , Allard Louise , Lerouge Sophie , Ohayon Jacques , Soulez Gilles
Published: May 2013

The objective is to show the feasibility of shear strain elastography (SSE) in vivo with intravascular ultrasound (IVUS) radio-frequency data acquired at 20 MHz in carotid arteries of pigs. We previously proposed the Lagrangian Speckle Model Estimator (LSME) to estimate the strain tensor including the shear strain that could be involved in atherosclerotic plaque hemorrhage, inflammation, and rupture mechanisms. However, the LSME performance to compute SSE had never been validated. Atherosclerotic pigs with significant plaques on carotids were studied. To induce atherosclerosis, pigs were put on an atherogenic diet and partial ligations of common carotid arteries were performed. Diabetes was induced by selective intra-arterial injection of streptozotocin. IVUS acquisitions were performed before sacrifice and histologic analysis were realized on fixed dissected carotids. SSE maps at end diastole were estimated with a new implementation of the LSME and matching with histology sections was realized. SSE clearly identified all plaques; reported figures show SSE mapping characterized by cohabitation of high positive and high negative shear values in the specific region of the plaque. This study demonstrates the performance of the LSME implementation to estimate accurately the shear strain distribution, and the feasibility of SSE to highlight atherosclerotic plaque vulnerability characteristics.
Hepatitis fibrosis characterization by a multiparametric study
Authors: Meziri Mahmoud , Bouzitoune Razika , Remita Naamane , Machado Christiano , Pereira Wagner.C. A , Padilla Frédéric
Published: May 2013

The ultrasonic tissue characterization (UTC) is primarily based on radio-frequency (RF) signals’ analysis. The processing of these signals allowed the estimation of different quantitative ultrasonic parameters (backscattered coefficients—ICB-, velocity—SoS, etc). It is known that the RF contains information that can be used to noninvasively characterize the structural and mechanical properties of tissue. Scatterer diameter (or size) from ICB measurements have been already used to discriminate fibrosis from normal tissue. From these findings, our goal was to evaluate the scatterer diameter to test its potential in the discrimination of fibrosis groups (F0, F1, F2, F3, and F4, METAVIR scale) from 20 in-vitro human liver samples, explored at 20 MHz. The mean scatterer diameters (µm) measured were: 42.14–4.90 (F0), 40.18–10.51 (F1), 38.82–6.05 (F3), and 40.30–2.22 (F4). The Kolmogorov-Smirnov test has shown a non-significant level (p > 0.05) indicating that the scatterer size estimation alone cannot differentiate between all fibrosis groups; an obvious overlap between groups appears. However, for the two different combinations (ICB, Size) and (ICB, Size, SoS), the discriminant analysis has correctly classified 75% and 85%, respectively, of liver samples at a significant level (p < 0.00005). The multiparametric study could play an important role to aid in the diagnostic of liver fibrosis.
Acoustical imaging of internal spheroid structures at a variety of frequencies
Authors: Berndl Elizabeth S. , Kolios Michael C.
Published: May 2013

We have previously shown that ultrasound is capable of identifying apoptosis in individual cells and cell pellets due to changes in the ultrasound attenuation, speed of sound, and backscatter. Spheroids can be used to more accurately model non-vascularized tumors due to their three-dimensional growth pattern, cell-cell interaction, disorganized growth, and development of a necrotic core when grown to sufficiently large sizes. To examine cell death in spheroids due to necrosis or chemotherapy, quantitative ultrasound methods were used on the ultrasound backscatter power spectrum throughout the spheroid. MCF7 spheroids ranging in size from 100 to 1000 μm were probed at 25 and 55 MHz using a VEVO770 high frequency ultrasound machine, and at 80 and 200 MHz using an acoustic microscope. Changes in spheroid structure as the necrotic core develops, and after it is exposed to chemotherapeutic agents were recorded and analyzed. An increase in the ultrasound backscatter amplitude from necrotic cells within the core of the spheroid versus the viable cells around the core was observed. Changes in the ultrasound backscatter were also observed for spheroids treated with chemotherapeutics to induce apoptosis. This work furthers our understanding of non-invasively identifying the viability of cancerous tumors, and the efficacy of chemotherapeutic treatments.
Using inter-individual standard deviation of hearing thresholds as a criterion to compare methods aimed at quantifying the acoustic input to the human auditory system in occluded ear scenarios
Authors: Blau Matthias , Sankowsky-Rothe Tobias , Köhler Simon , Schmidt Jan-Henning
Published: May 2013

Occluded ear scenarios are found in many applications, e.g., hearing aids or insert ear phones. Unfortunately, the correct quantification of the acoustic input delivered to the auditory system in such a scenario is complicated by the individual character of our outer ear anatomy. For instance, one can easily observe inter-individual differences in ear drum pressure level of up to 30 dB at 10 kHz with one and the same sound source. We may thus ask: (1) Is the sensitivity of our auditory system at threshold adapted to our outer ear anatomy? and (2) what is the best method to quantify the acoustic input? We propose to use the inter-individual standard deviation of hearing thresholds as a means to answer these questions: The quantity that is best suited to describe the input to the auditory system should result in the lowest inter-individual standard deviation of thresholds. Preliminary results based on tests with custom ear shells and with foam ear plugs show that up to 6 kHz, there are no significant differences between the methods tested, whereas in the 6–9 kHz frequency range, individual estimates of the sound pressure at the ear drum yield a significantly lower inter-individual standard deviation than, e.g., the ear simulator pressure.
Effect of the middle ear cavity on the response of the human auditory system
Authors: Garcia-Gonzalez Antonio , Gonzalez-Herrera Antonio
Published: May 2013

The effect of the acoustic cavities on the response of the auditory system has been usually focused on the influence of the external ear canal (EEC). The presence of the middle ear cavity (MEC) has been ignored. Experimental difficulties to obtain information inside this cavity without altering the whole system make difficult its study. In order to explore the influence of this cavity, a numerical study is made. This is made by means of a complete finite element (FE) model including the tympanic membrane, ossicular chain, and acoustic cavities. Different FE models are used to analyze the influence of each component. By means of different calculations removing these components from the model, their relative effects can be distinguished. At low frequencies (below 2 kHz) the influence of the MEC is negligible. Piston-like motion is dominant. Nevertheless, at higher frequencies a new resonant peak appears at a frequency of 4 kHz. This is due to the presence of the MEC. It combine with the pressure gain due to the ear canal (at a frequency of 3 kHz) increasing the response of the system in terms of Umbo velocity. This effect is observed in different published experimental results.
Estimation of ideal open-cavity middle-ear responses from responses with partial cavity opening
Authors: Maftoon Nima , Funnell W. Robert J. , Daniel Sam J.
Published: May 2013

An important step in developing mathematical models of the middle ear is the validation of simplified models without the middle-ear air cavity. However, open-cavity experimental results are often collected with only a partial opening of the middle-ear cavity, due to experimental limitations. The partial opening introduces an anti-resonance that obscures features of the frequency response in its neighborhood. In this study, we suggest a numerical method for estimating ideal open-cavity responses from experimental results with partial openings. We fit rational-fraction polynomials to portions of the response in order to parametrically identify the transfer function associated with the anti-resonance. The ideal open-cavity response is then estimated by dividing the experimentally measured frequency response by the identified anti-resonance transfer function. The method has been validated against synthesized transfer functions with features similar to those caused by partial opening of the cavity and against responses calculated using models of the middle ear with a partially open cavity.
Finite-element modeling of the newborn ear canal and middle ear
Authors: Motallebzadeh Hamid , Gariepy Brian , Maftoon Nima , Funnell W. Robert J. , Daniel Sam J.
Published: May 2013

Available hearing-screening procedures cannot distinguish clearly between conductive and sensorineural hearing loss in newborns, and the results of available diagnostic tests in very young infants are difficult to interpret. Admittance measurements can help to detect conductive losses but do not provide reliable results for newborns, where the ear is anatomically different from the adult ear. Finite-element models of the newborn ear canal and middle ear were developed and their responses were studied for frequencies up to 2000 Hz. Material properties were taken from previous measurements and estimates, and the sensitivities of the models to these different parameters were examined. The simulation results were validated through comparison with previous experimental measurements. Simulations indicate that at frequencies up to 250 Hz the admittance of the canal wall is comparable to that of the middle ear in the newborn. Above 250 Hz, the canal-wall admittance remains almost constant but for the middle ear there is a clearly defined resonance peak, which produces an admittance much larger than that of the canal wall. These results suggest that admittance measurements in the vicinity of the middle-ear resonance frequency can provide clinically useful information about the newborn middle ear.
Enhancing noise control in a cavity using Helmholtz resonators
Authors: Reddi Ch. Surya Narayana V. , Padmanabhan Chandramouli
Published: May 2013

In this paper, it is shown that there is a decrease in sound levels, not only when a resonator is tuned exactly to a cavity mode, but also when it is tuned to a frequency slightly different from the natural frequency of the chosen cavity mode. The finite element (FE) method is used for numerical modeling of the coupled Helmholtz resonator-cavity system. To validate the FE model prediction, a boundary element (BE) analysis is performed by specifying an impedance boundary condition on the element where the resonator is mounted. This impedance has been calculated, from a BE model of the resonator alone, using a plane wave excitation, over a range of frequencies around the cavity mode of interest. Numerical experiments have been performed in a cavity with two close modes (155 and 173 Hz) and it is observed that when a resonator is tuned to a frequency slightly lower than the first cavity mode, the performance of the resonator is much better than when it is tuned exactly to the first cavity mode or tuned to a slightly higher frequency. A detailed parametric study has been carried out and guidelines for tuning resonators for superior noise control is proposed.
Acoustical impedance characterization of liners using a Bayesian approach
Authors: Buot de l'Epine Yorick , Chazot Jean-Daniel , Ville Jean-Michel
Published: May 2013

Acoustic liners composed of perforated plates and honeycomb layers are used in several applications. These liners are used for example in aerospace as acoustic treatments for aircraft nacelles. To describe their behavior, empirical models or standing wave tube experiments can be employed. However, the resulting impedance is not always accurate to describe the real behavior of the liner when submitted to several planes waves at various angles (higher order modes in the duct), or when submitted to a grazing flow. In this paper, an inverse method based on a Bayesian approach is presented in order to characterize acoustic liners in real conditions. An analytical solution and experimental data are used to calculate the likelihood function of the estimated impedance. The posterior probability density function can then be obtained by adding the prior information. Finally, an evolutionary Markov Chain Monte Carlo method (eMCMC) is implemented to explore the probability density space. This inverse method is first validated on simulated data. Then experimental data are used.
Pressure mapping system based on guided waves reflection
Authors: Quaegebeur Nicolas , Masson Patrice , Beaudet Nicolas , Sarret Philippe
Published: May 2013

In this paper, guided wave interaction is used to develop a pressure mapping system for medical and touch-screen applications. The principle is based on interaction of guided waves in the presence of an added local mass and in the presence of a local pressure. For this purpose, piezoceramics are used for injecting guided waves into a thin structure and to measure the reflected waves due to the presence of an added mass or pressure. SHM imaging algorithms, based on time-of-flight (EUSR) or correlation (Excitelet), are implemented in order to obtain cartography of the reflections and deduce the presence, localization, and intensity of local contact spots. Analytical and numerical models are first derived to assess the critical parameters in order to maximize the reflection of guided waves (first order modes A0 and S0). It is shown that the sensitivity of the guided waves with respect to an added mass and pressure is highly related to the Young’s modulus of the host structure. Validation on a 0.5 mm thick plane aluminum plate prototype is addressed using 4 sensor/actuator pairs. It is observed that imaging of single pressure spot and multiple or extended pressure spots can be achieved using S0 mode around 300 kHz with a resolution of 0.5 mm.
Sound generation using photoacoustic effect
Authors: Yamabe Kaoru , Oikawa Yasuhiro , Yamasaki Yoshio
Published: May 2013

It is highly important to generate sound sources in mid air for several applications such as virtual realty and rigorous acoustic measurement. One possible solution for generating sound sources in mid air is photoacoustic effect that generates sounds from the alternate-current component of air expansion due to the heat generated by light absorption of materials when the materials are radiated light modulated with acoustic signal. Our previous research confirmed that audible sound could be generated by radiating light modulated with acoustic signal to charcoal, which has high absorptive power. Therefore, it is possible to generate point sound source in mid air by applying this method to molecule of gases in mid air. However, gases are difficult to absorb light since gases have low density of molecule. Thus in this paper, as the preliminary step applying photoacoustic effect to gas molecule, it is discussed to generate audible sound by radiating light modulated with acoustic signal to liquid phase of H2O and solid phase of CO2. These molecules of greenhouse gases can absorb infrared light that is safer than ultraviolet light that is absorbed by monatomic molecules such as N2 and O2.
How can we deduce playing frequencies from measured resonance frequencies for trumpets?
Authors: Caussé René E. , Eveno Pauline , Gilbert Joël , Petiot Jean-François
Published: May 2013

Lip-type valve (“striking outwards” type) is responsible for sound production for brass instruments. The operation of the valve is controlled by feedback from a passive resonator. The purpose of this study is to compare experimentally how far the resonance frequencies of instrument, taken from their input impedance (which does not involve the intervention of the player's lips) are able to give informations about the playing frequencies. A family of three trumpets made from a basic instrument for which the lead pipe will be slightly modified for each model, were considered for the experiment. Four expert musicians were asked to play the first five playable notes, for four different fingerings and for three nuances. This exercise was repeated three times. All these notes allow to make a quantitative assessment of the relation between the resonance frequencies and the playing frequencies, using in particular statistical methods. Several results will be presented: the influence of the player on the overall intonation, the effect of nuances on the pitch and the relation between small changes of geometry and playing frequencies. Functions made from the input impedance, such as the « sum function » proposed by Wogram, do not bring more relevant informations than the input impedance itself.
Comparing steady-state and transient phenomena in brass instruments
Authors: Hoekje Peter L.
Published: May 2013

Input impedance and radiation patterns are well-known examples of important brass instrument characteristics measured under steady state conditions. Transient phenomena are less studied, but potentially as important to the player and listener. For example, the heights and harmonicity of the peaks of the instrument's input impedance affect its steady-state playing response, which the player might describe on a range from “stuffy” to “open” or “free-blowing.” However, the player also wants an instrument that will facilitate clean and reliable attacks. The development of the instrument's pressure spectrum during the onset transient can serve as an additional diagnostic tool to reveal information about the instrument response under playing conditions. The contribution of the instrument body vibrations to the radiated sound field is small and generally imperceptible under steady-state conditions. However, the bandwidths of the body vibration resonances are generally much narrower than those of the air column resonances and accordingly their transient responses are much longer. This leads to a time signature that enhances their detection by the listener. A complete picture requires consideration of both the steady-state and transient phenomena.
Nonlinear wall vibration and wave steepening contributing to tonal metallicness and brassiness in a horn
Authors: Ebihara Takayasu , Yoshikawa Shigeru
Published: May 2013

It is well known that wave steepening and shock-wave formation due to nonlinear propagation through the bore are responsible for tonal brassiness of brass instruments. On the other hand, penetrating metallic tones are produced by hand-stopping the French horn. The present study demonstrates that the mechanism account for tonal metallicness of the French horn is nonlinear wall vibration of the bell. The measured waveforms of radiated pressure of the stopped tones indicate rapidly corrugating changes, which are not observed in brassy tones. Also, their spectra show much larger amplitudes of higher harmonics than those in normal mezzo-forte playing. The measurement of the wall vibration at the bell in hand stopping demonstrates similar characteristics. These results suggest that the bell wall vibration is responsible for the radiated tone color. Excitation experiments on the bell are carried out to elucidate the mechanism how the higher harmonic vibration is generated in hand stopping. They indicate that wall vibrations over 3 kHz are excited by the superharmonic generation derived from the geometrical nonlinearity of the bell. Moreover, for a direct support to our inference above, sound pressure of the stopped tone radiated when the horn bell is heavily damped will be examined.
Effects of reverberation and noise on speech comprehension by native and non-native English-speaking listeners
Authors: Peng Zhao , Wang Lily M. , Lau Siu-Kit , Steinbach Adam M.
Published: May 2013

Previous studies have demonstrated the negative impact of adverse signal-to-noise-ratios on non-native English-speaking listeners’ performance on speech recognition using recall tasks, as well as implied that comprehension skills were more impaired than recognition skills under reverberation and noise. The authors have themselves previously conducted a pilot study on three native and three non-native English-speaking listeners to examine the effects of reverberation and noise using speech comprehension tasks. Those results suggested that speech comprehension performance is worse under longer reverberation times (RT), and that a longer RT is more detrimental to speech comprehension by non-native listeners than native listeners. This paper reports on the refined full study, in which a larger number (up to 30) of each group was tested. Each participant was exposed to 15 acoustic conditions, created from combinations of five RTs (0.4 to 1.2 s) and three background noise levels (RC-30, 40, and 50). Speech comprehension performance under each condition was recorded. Confounders related to general speech comprehension abilities were screened for, including listening span, oral comprehension abilities, and English verbal skills. Results are presented and compared between native and non-native listeners. [Work supported by a UNL Durham School Seed Grant and the Paul S. Veneklasen Research Foundation.]
General nonlinear acoustical equation of relaxing media and its stationary solutions
Authors: Molevich Nonna , Galimov Rinat N. , Makaryan Vladimir G. , Zavershinskii Dmitriy I. , Zavershinskii Igor P.
Published: May 2013

During previous years, the conditions for the negative second (bulk) viscosity existence were found in a large number of nonequilibrium media. The media with negative viscosity possess a number of new properties including acoustical activity. In the present paper, we investigate the nonlinear stage of acoustical perturbation evolution in acoustically active nonequilibrium media using three models: the vibrationally excited gas with the exponential model of relaxation, the chemical active two component mixture with a nonequilibrium reaction and media with the general heat-loss function. The general nonlinear acoustical equation describing stationary density profiles behind the shock wave front in these media is obtained and solved. Its low- and high- frequency limits correspond to the Kuramoto-Sivashinsky equation and the Burgers equation with a source, respectively. Stationary structures of general equation, the conditions of their establishment and all their parameters are found analytically and numerically. In acoustically active media, it is predicted the existence of the stationary solitary pulse. Unstable weak shock waves disintegrate into the sequence of solitary pulses. Their amplitude, form, and speed are rigidly defined by the nonequilibrium degree and do not depend on the initial weak perturbation amplitude. For weak nonequilibrium degree, this solitary pulse is described analytically.
Perturbation methods for the spectral analysis of a weakly nonlinear acoustic field generated by a transient insonation
Authors: Khelladi Hassina , Rahmi Fahim
Published: May 2013

In this study an infinite plane piston is considered which oscillates with finite amplitude in unbounded homogeneous fluid. To illustrate the shape of the weakly nonlinear acoustic field generated by a transient insonation, the function defined by Funch/Muller representing a damped sinusoid is used to simulate the temporal waveform of the piston vibration. The acoustic transient wave generates harmonic components as result of nonlinearities in the material properties of the fluid and in the convective terms of the propagation equation. The mathematical approach is based upon the generalized Burgers’ equation, which is a good approximation of the exact equation for the nonlinear propagation when diffraction effects are assumed to be negligible. The pressure amplitude of the fundamental is considered large enough to produce the second harmonic wave. Under the quasi-linear approximation, an analytical description of the fundamental and the second harmonic waves is elaborated. To simulate the spectrum of the weakly nonlinear acoustic field, the pressure field is written in a perturbation series where the first term is the linear acoustic field that results from an infinitesimal oscillation of the piston and the second term contains the first nonlinear contribution to the acoustic field due to the finite amplitude effects.
Hysteresis of mode transitions with varying cavity length of bottle-shaped thermoacoustic prime movers
Authors: Andersen Bonnie , Pease David , Wright Jacob
Published: May 2013

Transition regions to higher resonant modes of a bottle-shaped thermoacoustic prime mover (neck: 5.39 cm long, 1.91 cm ID; variable cavity with a sliding piston: up to 38 cm long, 4.76 ID) were studied. The neck and cavity regions behave as coupled resonators. A variable cavity with a sliding piston was constructed to study the nature of the device as the cavity length is varied. The dominant mode of operation depends on the length of the cavity, favoring successively higher modes as the cavity length increases, occurring roughly where the higher mode overlaps with the fundamental frequency of the neck region. As the cavity length is increased, the transition of the dominant frequency from the fundamental to the first overtone occurs. However, when the length is then shortened, transition back to the fundamental does occur at the same piston position, revealing hysteresis. Three transitions to higher modes were observed. The hysteresis was studied as a function of input power (12.0–16.5 W) and stack volume filling factor (3.0–4.9%). Preliminary results indicate that the transition region occurs shallower in the cavity and the hysteresis widens as the input power is increased. Decreasing the stack mass causes an increase of the hysteresis width, but has no strong effect on the hysteresis depth.
Modeling music perception in impaired listeners
Authors: McKinney Martin , Fitz Kelly , Kalluri Sridhar , Edwards Brent
Published: May 2013

We employ computational models of loudness and pitch perception to better understand the impact of sensorineural hearing loss on music perception, with the aim of guiding technology development for hearing-impaired listeners. Traditionally, hearing aid development has been geared towards improving speech intelligibility and has largely failed to provide adequate restoration of music to those with hearing loss. One difficulty with trying to improve music perception in impaired listeners is the absence of a good quantitative measure of music reception, analogous to speech reception measures like word-recognition rate. Psychoacoustic models for loudness and pitch allow us to guage quantitative parameters relevant to music perception and make predictions about the type of deficits listeners face. We examine the impact of hearing loss to predicted measures of loudness, specific loudness, pitch, and consonance and make suggestions on possible methods for restoration.
A model-based hearing aid: Psychoacoustics, models, and algorithms
Authors: Ewert Stephan D. , Kortlang Steffen , Hohmann Volker
Published: May 2013

In hearing aids, amplification and dynamic range compression typically aim at compensating the deficits associated with outer-hair cell (OHC) loss. Nevertheless, success shows large inter-individual variability and hearing-impaired listeners generally still have considerable problems in complex acoustic communication situations including noise and reverberation. These problems could be related to inner-hair cell (IHC) damage and reduced frequency selectivity resulting in a loss of spectro-temporal coding fidelity. Here a model-based, fast-acting dynamic compression algorithm which aims at approximating the normal-hearing BM input-output function in hearing-impaired listeners is suggested. The algorithm is fitted by estimating low-level gain loss (OHC loss) from adaptive categorical loudness scaling data and audiometric thresholds based on Ewert and Grimm [Proc. ISAAR (2012)] and Jürgens et al. Hear. Res. 270, 177 (2011)]. Aided speech intelligibility was measured in stationary and fluctuating noise and related to the estimated OHC loss. To improve diagnostics of OHC and IHC loss, a series of five psychoacoustic measurements was conducted aiming at a direct quantification of IHC damage in a group of six young and elderly normal-hearing and 12 hearing-impaired listeners. A model is suggested to account for the temporal fine-structure detection and discrimination data. [Work funded by BMBF 01EZ0741 and DFG FOR1732.]
Modal active control applied to simplified string musical instrument
Authors: Benacchio Simon , Mamou-Mani Adrien , Chomette Baptiste , Ollivier François
Published: May 2013

This study aims to control the vibrational eigenmodes of soundboards in order to modify the timbre of string instruments. These structures are wooden plates of complex shape, excited by a string through a bridge. Their modal parameters are first identified using modal analysis algorithms on experimental measurements. Then a digital controller is designed using these parameters and classic active control methods. The effects of this controller are first studied thanks to time simulation. Prior to applying experimentally this controller, an optimization procedure is carried out to determine the quantity, dimensions and positions of sensors and actuators needed for the control. These best possible specifications are obtained according to the controllability, observability and other optimization criteria. Finally, a real time system using the control procedure is tested on a simplified musical instrument. The experiment is conducted on a rectangular spruce plate, clamped at its boundary and excited by means of a single string. This simple case study is presented here and its results are discussed in terms of eigenmodes modifications.
Imaging crack orientation using the time reversed elastic nonlinearity diagnostic with three component time reversal
Authors: Anderson Brian E. , Ulrich Timothy J. , Le Bas Pierre-Yves
Published: May 2013

The time reversed elastic nonlinearity diagnostic (TREND) is a method to allow one to nondestructively evaluate a sample by locating nonlinear scatterers. In the TREND method one creates a localized focus of energy using time reversal at each point of interest. The localized nature of the focus, which is at a higher energy level relative to the wave field nearby thereby amplifying the potential nonlinear signature of the focal location, allows one to image localized nonlinearities. It has also been shown that a focus of energy may be individually created in each of the three independent vector components of vibration using time reversal. Here we show that the use of TREND scans in each of the three vector component directions allows imaging of a crack’s orientation. This work is conducted on steel samples, each with cracks at known orientations that were created in a controlled manner. The scaling subtraction method is also used at each scan point to classify the nonlinearity. [Work supported by Institutional Support (LDRD) at the Los Alamos National Laboratory.]
Intentionality and categories in speech motor control
Authors: Mitsuya Takashi , Munhall Kevin G.
Published: May 2013

Actions are organized around goals or intentions. In speech production, there has been no agreement on how best to discuss speech goals. However, the auditory feedback perturbation methodology provides a window into the nature of speech goals. To the extent that subjects are sensitive to variation in an acoustic attribute, this attribute must be part of the controlled intention of articulation. In this presentation, we will review a series of studies that speak to this issue. In one study, we examined how intentionality of speech production influences compensatory formant production by instructing subjects to use a cognitive strategy in order to make the feedback sound consistent with the intended vowel. In other studies, we have explored the specificity of vowel formant compensation by comparing cross-language differences. The results indicate that speech goals are (1) very specific, defined by a phonemic category and its relationship with neighboring categories, and (2) multivariate. We will discuss these results by contrasting compensatory behaviors in reaching and limb movements to those observed in speech studies. The presence of a system of categories in speech may result in differences in the way speech goals are represented.
Exploring auditory-motor interactions in normal and disordered speech
Authors: Tourville Jason A. , Cai Shanqing , Guenther Frank H.
Published: May 2013

Auditory feedback plays an important role in speech motor learning and in the online correction of speech movements. Speakers can detect and correct auditory feedback errors at the segmental and suprasegmental levels during ongoing speech. The frontal brain regions that contribute to these corrective movements have also been shown to be more active during speech in persons who stutter (PWS) compared to fluent speakers. Further, various types of altered auditory feedback can temporarily improve the fluency of PWS, suggesting that atypical auditory-motor interactions during speech may contribute to stuttering disfluencies. To investigate this possibility, we have developed and improved Audapter, a software that enables configurable dynamic perturbation of the spatial and temporal content of the speech auditory signal in real time. Using Audapter, we have measured the compensatory responses of PWS to static and dynamic perturbations of the formant content of auditory feedback and compared these responses with those from matched fluent controls. Our findings indicate deficient utilization of auditory feedback by PWS for short-latency online control of the spatial and temporal parameters of articulation during vowel production and during running speech. These findings provide further evidence that stuttering is associated with aberrant auditory-motor integration during speech.
The role of auditory feedback in speech development: A study of compensation strategies for a lip-tube perturbation
Authors: Menard Lucie , Perrier Pascal , Aubin Jerome
Published: May 2013

The role of auditory feedback in speech development was investigated through a study of compensation strategies for a lip-tube perturbation. Acoustic, articulatory, and perceptual analyses of the vowels /i/, /y/, and /u/ produced by ten 4-year-old French speakers and ten adult French speakers were conducted under two conditions: normal and with a 15-mm-diameter tube (for /y/ and /u/) or a 5-mm-diameter tube (for /i/) inserted between the lips. Ultrasound and acoustic recordings of isolated vowels were made in normal condition before any perturbation (N1), for each of the 20 trials in the perturbed condition (P), and in normal condition after the perturbed trials (N2). Data reveal that adult participants moved their tongue in the P condition more than children subjects, to compensate for F1 and F2 alteration induced by the tube. Except for /y/, the perturbation was generally at least partly compensated during the perturbed trials in adults and children, but children did not show a typical learning effect. Results are analyzed from the perspective of (i) goal specification in speech production in the acoustic and/or somatosensory domain, and (ii) the maturity of representations of the motor apparatus in the brain.
Perceptual integration of indexical information in bilingual speech
Authors: Vaughn Charlotte , Brouwer Susanne
Published: May 2013

The present research examines how different types of indexical information, namely talker information and the language being spoken, are perceptually integrated in bilingual speech. Using a speeded classification paradigm [Garner (1974)], variability in characteristics of the talker (gender in experiment 1 and specific talker in experiment 2) and in the language being spoken (Mandarin vs. English) was manipulated. Listeners from two different language backgrounds, English monolinguals and Mandarin-English bilinguals, were asked to classify short, meaningful sentences obtained from different Mandarin-English bilingual talkers on these indexical dimensions. Results for the gender-language classification (Exp. 1) showed a significant, symmetrical interference effect for both listener groups, indicating that gender information and language are processed in an integral manner. For talker-language classification (Exp. 2), language interfered more with talker than vice versa for the English monolinguals, but symmetrical interference was found for the Mandarin-English bilinguals. These results suggest both that talker-specificity is not fully segregated from language-specificity, and that bilinguals exhibit more balanced classification along various indexical dimensions of speech. Currently, follow-up studies investigate this talker-language dependency for bilingual listeners who do not speak Mandarin in order to disentangle the role of bilingualism versus language familiarity.
Prosodic correlates of smiled-speech
Authors: Émond Caroline , Laforest Marty
Published: May 2013

Smiling is a visible expression and an audible one too when it is synchronous with speech. Very few studies have documented the perceptual prosodic cues associated with perceived smiling speech. The first aim of this paper is to study the perception of smiled-speech according to the listeners’ gender. The reaction time and the intensity of the perceived smiled-speech were also investigated. The second aim is to identify a combination of prosodic parameters which would allow a phonetic description of smiled-speech. 140 utterances were extracted from spontaneous data (Montréal 1995 corpus) and used as stimuli for a perception test administered to 40 Québec French listeners (20 men, 20 women). Results show that men and women do not perceived smiled-speech in the same way, and women are quicker than men to make their decisions. Moreover, reaction times are faster for utterances perceived as smiling with a high degree of intensity, for both men and women, than those with lower intensity. Perceived prosodic parameters related to pitch height, pitch range, rhythm, and speech rate in relation to smiled-speech and its intensity are also discussed.
Vowel production in Mandarin accented English and American English: Kinematic and acoustic data from the Marquette University Mandarin accented English corpus
Authors: Ji An , Berry Jeffrey J. , Johnson Michael T.
Published: May 2013

Few electromagnetic articulography (EMA) datasets are publicly available, and none have focused systematically on non-native accented speech. We introduce a kinematic-acoustic database of speech from 40 (gender and dialect balanced) participants producing upper-Midwestern American English (AE) L1 or Mandarin Accented English (MAE) L2 (Beijing or Shanghai dialect base). The Marquette University EMA-MAE corpus will be released publicly to help advance research in areas such as pronunciation modeling, acoustic-articulatory inversion, L1-L2 comparisons, pronunciation error detection, and accent modification training. EMA data were collected at a 400 Hz sampling rate with synchronous audio using the NDI Wave System. Articulatory sensors were placed on the midsagittal lips, lower incisors, and tongue blade and dorsum, as well as on the lip corner and lateral tongue body. Sensors provide five degree-of-freedom measurements including three-dimensional sensor position and two-dimensional orientation (pitch and roll). In the current work we analyze kinematic and acoustic variability between L1 and L2 vowels. We address the hypothesis that MAE is characterized by larger differences in the articulation of back vowels than front vowels and smaller vowel spaces compared to AE. The current results provide a seminal comparison of the kinematics and acoustics of vowel production between MAE and AE speakers.
Articulatory parameterization in Trique tone production: Distinguishing co-production from coarticulation
Authors: DiCanio Christian , Nam Hosung
Published: May 2013

The production of a tone in a tonal language is typically influenced by adjacent tonal targets. Within the literature, all such influences on F0 are considered part of tonal coarticulation. Yet, conflating all these effects under “coarticulation” results in an assortment of different processes within a tone language which lack a common motivating principle. In this talk, we present original tone production data from Itunyoso Trique (Oto-Manguean). The data consists of five repetitions of 24 sentences spoken at two speech rates (fast/normal) by eight native speakers. The medial target word was one of four tones (/45/,/4/,/32/,/2/), while the adjacent words were one of six tones (/45/,/43/,/32/,/3/,/2/,/1/). F0 data was extracted and time-normalized. Two patterns were observed. First, adjacent tones influenced F0 at the onset and offset of target tones. Second, global changes in F0 contour occurred for certain tones. All such effects were stronger during fast speech rate. We argue that these effects, often grouped together as coarticulation, have distinct explanations within an Articulatory Phonology framework. Transitional effects at tonal onsets and offsets are modeled by temporally modulating gestural activation intervals, resulting in articulatory undershoot between tones, whereas global changes in F0 contour are modeled by modulating gestural target parameters.
Effect of speech variable rate on the coarticulation in the right vocalic context of Arabic utterances VCV
Authors: Falek Leila , Teffahi Hocine , Djeradi Amar
Published: May 2013

Our study consists of analysing Arabic utterances VCVα in brief vocalic context with Vα and speech rate as variables in order to observe the impact of the “right” context and speech rate on the coarticulation. Thus, we have to look for some invariance in the speech signal explaining the coarticulation phenomenon related to speech rate. So, we have analyzed the formant tracking of the arabic pharyngeal / / (or (ɛ) in arabic) in vocalises contexts /a/, /u/ and /i/ with variables speech rates (normal, fast and slow) in interrogative sentences. That is in order to confirm the anticipatory phenomenon and observed the influence of speech rate variation on the vocal tract in articulation. The observed results have shown in our case the existence of anticipatory articulation and that it depends on speech rate. (Non existence in slow rate, however, with more prominence in normal or fast rate.)