bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal ablation by high-intensity-focused ultrasound using a toroidal transducer for the treatment of colorectal liver metastases during an open procedure. Clinical results
Authors: Melodelima David , Vincenot Jeremy , Chen Yao , Dupre Aurelien , Rivoire Michel , Chapelon Jean-Yves
Published: May 2013

The objective of this clinical study was to validate the effectiveness, accuracy, tolerance, and safety of a HIFU treatment developed for the treatment of liver metastases. Fifteen patients were included. The transducer has a toroidal shape (diameter: 70 mm, radius of curvature: 70 mm) and was divided into 256 ultrasound emitters operating at 3 MHz. A 7.5 MHz ultrasound imaging probe was placed in the center of the device. All HIFU ablations were obtained in 40 s. The demarcation between ablated and non-ablated tissue was clearly apparent in ultrasound images and histology. In phase I (6 patients), we demonstrated that the dimensions of HIFU ablations measured on ultrasound imaging were correlated (r = 0.88) with dimensions measured during histological analysis. The average dimensions obtained from each HIFU ablation were a diameter of 21.0 ± 3.9 mm and a depth of 27.5 ± 6.0 mm. In phase II (9 patients), the HIFU ablations were centered on a target previously identified with a precision of 1–2 mm. It was demonstrated that HIFU ablations can be precisely located at 7.0 ± 2.3 mm from the target (expected distance 7.5 mm). This toroidal HIFU transducer achieved fast, selective, safe, and well-tolerated large volume liver ablation.
Investigation of vibrations of piezoelectric spherical shells with axisymmetric holes
Authors: Brown David A. , Brown Colton T.
Published: May 2013

An experimental investigation of the vibration of radially polarized thin-walled piezoelectric ceramic spherical shells with axisymmetric holes is presented. Piezoelectric spherical electroacoustic transducers having holes at their poles to permit passage of wires, cables, or structural members is of particular interest in underwater acoustics. The coupled vibrations follow three resonance branches corresponding to (0) azimuthal extensional modes, (1) bending flexural modes, and (2) meridional extensional modes. The resonances and effective electromechanical coupling coefficient for each mode as a function of the hole-to-sphere diameter ratio have been determined from admittance measurements. In the limit that the hole-to-sphere diameter ratio approaches zero, the (0) mode is dominant corresponding to the spherically symmetric breathing mode having a measured coupling coefficient of 0.546, which is consistent with the planar coupling coefficient for PZT-4 (Type I) material. In the limit that ratio approaches unity, the element in nearly cylindrical and the lowest (0) mode corresponds to the breathing mode of a ring having a coupling coefficient of about 0.33, which is consistent with the transverse (31) coupling coefficient for the material. The focus of the study is on determining the resonances and electromechanical coupling in the intermediate region and obtaining corresponding vibration mode shapes with a non-contact optical fiber displacement sensor.
Calculation of characteristics of nonlinear normal waves in plates of lithium niobate for the designing of acousto-electronic devices
Authors: Kuslyva Alina , Storozhev Valery
Published: May 2013

The research of anharmonic effects is essential for the design of nonlinear acousto-electronic devices. Such effects involve the generation of nonlinear second harmonics in propagation of normal electroelastic waves in crystal plates. Thereby the analytical and numerical technique of the analysis of small nonlinear anharmonic effects in distribution of normal electroelastic waves in the layer of a trigonal piezocrystal of lithium niobate with thin short-circuited electroсonductive coverings of sides has been developed. The research is based on the model of physically and geometrically nonlinear electroelastic deformation with finite deformations and Gibbs's function that includes quadratic and cubic components on deformations and characteristics of intensity of quasistatic electric field. The analysis of nonlinear wave effects is build on the representation of characteristics of a normal electroelastic wave in the form of the sum of summands, which are proportional to the powers of the small parameter. The analytical form has been received for the representations of functions of the elastic displacements, intensity, induction of quasistatic electric field in nonlinear second harmonics for the studied waves from the different modes of the dispersive spectrum. Quantitative estimates have been researched for the amplitude levels of second harmonics for normal electroelastic waves with variable frequencies.
Accurate determination of piezoelectric ceramic constants using a broadband approach
Authors: Perez Nicolas , Andrade Marco Aurelio B. , Carbonari Ronny C. , Adamowski Julio C. , Buiochi Flavio
Published: May 2013

Piezoceramic property values are required for modeling piezoelectric transducers. Most datasheets present large variations in such values. For precise simulations, adjustments are necessary. Recently, the authors presented a methodology to obtain the real part of ten material constants of piezoelectric disks. It comprises four steps: experimental measurements, identification of vibration modes and their sensitivity to material constants, preliminary identification algorithm, and final refinement of the constants using an optimization algorithm. Given an experimental electrical impedance curve of a piezoceramic and a first estimate for the material constants, the objective is to find the constants that minimize the difference between the experimental and numerical curves. Using a new finite element method routine implemented in Matlab, the original methodology was extended to obtain the corresponding imaginary part of all the material constants. Results of sensitivity analysis for the imaginary part and the guidelines to construct an algorithm are presented. This complex model allows adjusting the amplitude over a wide frequency range, as opposed to the models described in the literature. It is applied to 1-MHz APC850 disks with diameters of 10 and 20 mm. The methodology was validated by comparing the numerical displacement profiles with the displacements measured by a laser Doppler vibrometer.
Enriching the aural experience in audio education
Authors: Case Alex
Published: May 2013

Audio education’s essential outcome is aural. Lectures and readings on aesthetics, techniques, and technologies can never communicate audio concepts effectively without critical elucidation through sound. Quality audio education has always made frequent use of laboratories, recording sessions, and critical listening classrooms to keep sound at the center of student learning. Recently authored and published web-based multimedia and digital audio workstation self-study experiences are discussed and demonstrated. The sonic illustrations, visual reinforcement, and associated interactivity are found to provide meaningful pedagogical advancements in audio education.
Sonority in British English
Authors: Nakajima Yoshitaka , Ueda Kazuo , Fujimaru Shota , Ohsaka Yuki
Published: May 2013

Our previous study on British English speech [Nakajima et al.; Fechner Day (2012), Ottawa] was extended into the domain of phonology. Factor analyses were performed on the power fluctuations of the outputs of 19 critical-band filters, which separated British English sentences uttered by two female speakers and one male speaker into narrow-band signals. A database of British English spoken sentences [The ATR British English speech database (Campbell, 1993)] was used for the present analysis, because each identifiable speech sound was indicated in the speech waveform with a label of a phonetic symbol. About 80% of 31,663 labels were considered to represent English phonemes. Three factors appeared as in our previous research [Ueda et al.; Fechner Day (2010), Padova], and one of them corresponding to a frequency range of about 600–1800 Hz was closely related to sonority or aperture described in linguistics literature. The acoustic sonority could be related to a few phonological phenomena: (1) A sonorant consonant immediately after an obstruent can be a syllable nucleus, (2) a consonant cluster at the beginning of a word mostly begins with an obstruent, and (3) a short schwa cannot be a nucleus of a stressed syllable.
Toward the development of objective difficulty measure in technical ear training tasks
Authors: Marui Atsushi , Kamekawa Toru
Published: May 2013

Technical Ear Training is a method to improve the ability to focus on a specific sound attribute. It is also used to be able to communicate using the common language used in the industry such as Hz and dB. Although it is essential to gradually harden the task difficulty for successful technical ear training, the objective measure of the difficulty is still not known. Therefore, the tasks are decided by the teacher's own ears and experiences, leading to inefficiency when students want to train themselves in the teacher's absence. As the first step toward understanding this tacit ability of knowing the task difficulty, the authors investigated the correlation between the students' subjective ratings of the task difficulty and the physical measures calculated from the sound materials used in the training. A linear regression model (R2 = 0.629) which predicts the subjective task difficulty from residual of the linear fit through the spectra of the sound material was created. This model may provide a firm step toward the goal of developing objective difficulty measure in technical ear training.
Computational analysis of the dynamic flow in single-reed woodwind instruments
Authors: da Silva Andrey R. , Yong Shi , Scavone Gary
Published: May 2013

The dynamics of the air flow within the mouthpiece of single-reed wind instruments makes an important contribution to the acoustic behavior of this type of system, particularly during transient regimes. In this work, a two-dimensional numerical model of the mouthpiece-reed system is used to evaluate the behavior of the flow within the mouthpiece at three different frequencies within the playing range of the clarinet. The relationship between volume flow and blowing pressure, as well as the behavior of the vena contracta during one duty cycle are compared with the available analytical models and with recent experimental observations.
Physical modeling of bilabial plosives production
Authors: Delebecque Louis , Pelorson Xavier , Beautemps Denis , Laval Xavier
Published: May 2013

The context of this study is the physical modeling of speech production. The first step of our approach is to realize in vivo measurements during the production of the vowel-consonant-vowel sequence /apa/. This measurements concerns intra oral pressure, acoustic pressure radiated at the lips and labial parameters (aperture and width of the lips) derived from a high-speed video recording of the subject's face. In a second time, theoretical models from speech production literature are under investigation to describe air flow in the lips. Their prediction are compared with measurements obtained using an experimental set-up including a replica of vocal folds, which are able to self-oscillate and a rigid replica of lips. Finally, this validation allows us to achieve numerical simulations of the sequence /apa/. The comparison between the measured intra oral pressure and the simulated one leads us to take into account for the cheeks expansion in the physical modeling of bilabial plosives.
Influence of cross section shape on the outcome of a two-mass model
Authors: Wu Bo , Van Hirtum Annemie , Luo Xiaoyu
Published: May 2013

For the last decades, the two-mass model has shown its value to model the fluid-structure interaction during voiced speech production. Its main interest lies in its simplicity since it allows a quasi-analytical solution for a complex phenomenon using only a limited amount of physical meaningful parameters. Nevertheless, the use of the two mass model with respect to model speech pathologies can be questioned due to the lack of detail in the used mechanical and/or flow model. In the current paper, we focus on the influence of the cross section shape taken into account. Indeed, varying the cross section shape is likely to alter the pressure distribution due to viscous effects. The influence of the cross section shape on the flow outcome is modeled as well as experimentally assessed. Next, the influence of varying the cross section shape on phonation parameters such of the threshold pressure and fundamental frequency are addressed by considering a linear stability analysis of the two mass model.
The spectral and acoustical impact of vowel changing in choral tuning
Authors: Delvaux Bertrand , Howard David
Published: May 2013

Mixed soft/solid models of the vocal tract were moulded with a 3D rapid prototyping technique based on MRI data obtained from two male singers during the phonation of five English vowels as in hard, stern, neap, port, and food. The replicas are used to assess the interaction of several vocal tracts in different settings: twice the same singer or two different singers, singing on the same vowel or on different vowels, on a consonant or a dissonant interval. The spectral output is analyzed and the acoustical output is submitted to a listening test to evaluate the spectral and acoustical grounds for an interval/chord to perceptually sound “in tune.”
Activities of the Acoustical Society of America's subcommittee on wind turbine noise and some studies being done
Authors: Timmerman Nancy
Published: May 2013

This paper will document the activities of the Acoustical Society of America's (ASA's) subcommittee (of the Panel on Public Policy) on Wind Turbine Noise, including what technical committees are represented, what special sessions will be held in the future, and the goal to generate a policy statement on the topic. The author, who is Chair of this subcommittee, will also describe what other current studies are or have been done in Massachusetts (in the United States) and, if applicable, elsewhere.
Amplitude modulation of audible sounds by non-audible sounds: Understanding the effects of wind turbine noise
Authors: Lichtenhan Jeffery , Salt Alec
Published: May 2013

Our research has suggested a number of mechanisms by which low-frequency noise could bother individuals living near wind turbines: causing endolymphatic hydrops, exciting subconscious pathways, and amplitude modulation of audible sounds. Here we focus on the latter mechanism, amplitude modulation. We measured single-auditory-nerve fiber responses to probe tones at their characteristic frequency in cats. A 50 Hz tone, which did not cause an increase in spontaneous firing rate (i.e., was not audible to the fiber when presented alone) was used to amplitude modulate responses to the probe tone. We found that as probe frequency decreased, a lower level of the low-frequency non-audible tone was needed to achieve criterion amplitude modulation. In other words, low-frequencies that are coded in the cochlear apex require less low-frequency sound pressure level to be amplitude modulated as compared to higher-frequencies that are coded in the cochlear base. This finding was validated, and extended to lower frequencies, by amplitude modulating gross measures of onset-synchronous (compound action potentials) and phase-synchronous (auditory nerve overlapped waveforms) in guinea pigs. Our results suggest that that infrasound generated by wind turbines may cause amplitude modulation of audible sounds, which is often the basis for complaints from those living near wind turbines.
A robust numerical approach for prediction of turbofan engine noise
Authors: Habibi Kaveh , Gong Hao , Mongeau Luc
Published: May 2013

Noise from the aircraft jet engines is still the dominant source in takeoff condition. Government regulations of community noise are getting more stringent, creating significant challenges for aircraft manufacturers to meet these requirements. Expensive nature of experiments as well as accessing to powerful computers have provided new impetus for computational studies. In this paper, an efficient and robust numerical scheme, namely the Lattice Boltzmann Method was used to simulate the sound created by typical internal mixing nozzles with forced mixers. The simulation includes capturing the time-resolved flow characteristics and large scale turbulent structures. The sub grid scales were modeled using the renormalization group (RNG) forms of the standard k-ε equations. Several test cases including cold and hot core flow experiments conducted by NASA were selected for computational setup and validation purposes. The far field sound was predicted using a surface integral method. The near-field simulation results such as the jet centerline velocity decay and turbulence intensities as well as far-field sound were qualitatively in agreement with experimental results. The far-field sound analysis suggested significant low-frequency noise reduction for the lobed mixers, as well as significant reduction in overall sound pressure level (OASPL) in comparison with the simple confluent nozzle configurations.
Detached Eddy Simulation modeling and far-field trailing-edge noise estimation of a sharp-edged symmetric strut
Authors: Marshallsay Patrick G. , Brooks Laura A. , Cederholm Alex , Doolan Con J. , Moreau Danielle J. , Albarracin Cristobal
Published: May 2013

This paper presents results of a Computational Fluid Dynamic (CFD) study of a sharp-edged symmetric flat strut at Reynolds number 500,000 based on chord at zero degrees angle of attack, and the subsequent estimation of far-field noise generated at the trailing-edge. Flow field results obtained using Detached Eddy Simulation (DES) modeling and Reynolds-averaged Navier Stokes (RANS) modeling techniques are compared with empirical wind-tunnel data. The flow is observed to be physically complex in nature, exhibiting numerical solutions that are sensitive to the mesh grid and freestream turbulence intensity. Although originally developed for use specifically with RANS-generated flow data, the RANS-based Statistical Noise Model (RSNM) technique, which estimates far-field noise from mean turbulence data via an acoustic Green’s function and a statistical turbulence correlation model, is used here to estimate far-field noise spectra from both RANS and DES flow data. Far-field noise is also estimated from the DES model using the permeable surface form of the Ffowcs Williams and Hawkings (FWH) solver. The FWH estimate gives the closest match to experimental data, while the RSNM-generated noise estimate from the DES data appears to be more successful at capturing the large turbulent structures within the flow than the RANS data.
Preliminary analysis of acoustic intensity in a military jet noise field
Authors: Stout Trevor A. , Gee Kent L. , Neilsen Tracianne B. , Wall Alan T. , Krueger David W. , James Michael M.
Published: May 2013

Acoustic intensity measurements of the F-22A Raptor are analyzed as part of ongoing efforts to characterize the noise radiation from military jet aircraft. Data were recorded from a rig of microphones and an attached tetrahedral intensity probe at various locations to the sideline and aft of the aircraft. Numerical analysis of the intensity at one-third octave band center frequencies along various measurement planes and at a 23 m radius arc reveals the magnitude and directionality of the vector acoustic intensity. Differences in the trends for low-frequency and high-frequency data are discussed and, via a simple ray tracing back toward the source, interpreted in terms of source location and extent. [Work supported by ONR.]
The medial olivary complex reflex strength of children with auditory processing disorders
Authors: Kamdar Sangeeta , Jin Su-Hyun
Published: May 2013

The present investigation is designed to examine speech understanding in noise and the strength of medial olivary complex (MOC) reflex in children diagnosed with auditory processing disorder (APD). APD is a dysfunction associated with limited auditory processing of sounds. Individuals with APD do not show any peripheral hearing impairment but have difficulty understanding speech especially in the presence of noise. Recent neurophysiological studies suggest that the efferent system also make an important contribution. One of the most peripheral parts of the auditory efferent system is MOC system which projects from the auditory brainstem to the cochlea. The MOC system has been known to play an important role protecting the auditory system from intense noise and affecting tone detection or speech perception in noise [Micheyl and Collet (1996), Kumar and Vanaja (2004)]. The strength of this efferent feedback system can be assessed non-invasively through the contralateral suppression of distortion product otoacoustic emissions. It is hypothesized that children with APD show weaker MOC reflex strength compared to the normal peers. Based on the test results, possible efficient testing protocol and intervention program for this special population will be discussed.
Prolonged low-grade noise exposure induces aging-like functional and structural changes in cortical auditory pathways
Authors: Kamal Brishna , Ouellet Lydia , de Villers-Sidani Etienne
Published: May 2013

Age-related impairments in the primary auditory cortex (A1) include poor tuning selectivity, neural desynchronization, and degraded responses to low-probability or “oddball” sounds. These changes have been for the most part attributed to reduced inhibition in the aged brain. Since many of these changes can be partially reversed with auditory training, it has been speculated that they might not be purely degenerative but might rather represent negative plastic adjustments to noisy or distorted auditory inputs. To test this hypothesis, we exposed young adult rats to low-grade broadband noise for 6 weeks and then compared the effect of this exposure on several aspects of A1 function and structure. We found that the impact of noise exposure on A1 tuning selectivity and responses to oddball tones was almost undistinguishable from the effect of natural aging. These changes were paralleled by alterations in A1 inhibitory interneuron populations in the exposed group. Moreover we found that noise exposure reduced the anatomical and functional connectivity of A1 to downstream cortical fields. Most of these changes reversed after returning to a non-noisy environment. These results support the hypothesis that age-related changes in cortical auditory pathways might have a strong activity-dependent component, making them potentially preventable and reversible.
A computational model of spatial tuning in the auditory cortex in response to competing sound sources
Authors: Dong Junzi , Colburn Steven , Sen Kamal
Published: May 2013

Single neurons in the auditory midbrain are sharply tuned to preferred directions, while cortical neurons show broader tuning [King et al., Hearing Research (2007)] Recent experiments on cortical responses in birds revealed the emergence of spatial tuning to multiple competing sounds in the cortex [Maddox et al., PLoS Biol. (2012)]. In this situation, cortical neurons show broad tuning to single-location stimuli, but develop sharper spatial preference in response to a second competing noise source. We have developed a computational model to match these physiological data. The model takes binaural inputs containing sounds from two locations, and outputs cortical spike trains that emphasize one pre-defined location. In the model, sharply tuned midbrain neurons synapse onto their corresponding interneurons, which then innervate cortical neurons generating the final output. In the presence of stimulus from a pre-defined preferred location, corresponding interneurons actively suppress sources from a pre-defined non-preferred location. The model achieves spatial tuning by performing robustly when the target and masker locations match the pre-defined preferred and non-preferred directions. Looking across cortical neurons tuned to different target and masker combinations, the model provides a mechanism by which binaural inputs from a noisy environment can be separated into independent “streams” based on locations.
Interaction between resonant scaling and fundamental frequency on codings in auditory system
Authors: Matsui Toshie , Tsuzaki Minoru
Published: May 2013

It has been modeled that the auditory system encodes acoustic signals into two independent informations. One is tonotopic information reflecting the frequency response characteristics of the basilar membrane, and another is periodicity information reflecting the temporal patterns of phase-locked auditory nerve firing. Based on the previous study about size perception of sound source, a hypothesis can be proposed that the tonotopic and periodicity information are combined into an internal “two-dimensional representational plane.” The current study tested that this hypothesis by conducting an experiment to recognize the transition pattern of vowel-like sounds on the plane. Listeners were able to recognize the transition patterns on the axes of tonotopic and periodicity information exclusively. However, they were unable to follow the trajectories of sounds in the two-dimensional representational plane. The vowel-like sounds were simulated by a computational model of auditory system, AIM. While the “excitation pattern” displayed transition patterns corresponding to the manipulation of resonant scaling (RS) only, “Summary SAI” displayed both of patterns of fundamental frequency (F0) and RS. It suggests the need to confirm whether RS represented in periodicity information is used for size perception.
The effect of compression on tuning estimates in a simple nonlinear auditory filter model
Authors: Marschall Márton , MacDonald Ewen , Dau Torsten
Published: May 2013

Behavioral experiments using auditory masking have been used to characterize frequency selectivity, one of the basic properties of the auditory system. However, due to the nonlinear response of the basilar membrane, the interpretation of these experiments may not be straightforward. Specifically, there is evidence that human frequency-selectivity estimates depend on whether an iso-input or an iso-response measurement paradigm is used [Eustaquio-Martin et al. (2011)]. This study presents simulated tuning estimates using a simple compressive auditory filter model, the bandpass nonlinearity (BPNL), which consists of a compressor between two bandpass filters. The BPNL forms the basis of the dual-resonance nonlinear (DRNL) filter that has been used in a number of modeling studies. The location of the nonlinear element and its effect on the estimated tuning in the two measurement paradigms was investigated. The results show that compression leads to (i) a narrower tuning estimate in the iso-response paradigm when a compressor precedes a filter, and (ii) a wider tuning estimate in the iso-input paradigm when a compressor follows a filter. The results imply that if the DRNL presents a valid model of the basilar membrane, then compression alone may explain a large part of the behaviorally observed differences in tuning between simultaneous and forward-masking conditions.
The coda of the transient response in a sensitive cochlea
Authors: Li Yizeng , Grosh Karl
Published: May 2013

In a sensitive cochlea, the basilar membrane (BM) velocity response due to transient external acoustic excitation or to localized transient internal bipolar electrical excitation gives rise not only to a primary impulse response, but also to a coda of delayed secondary responses (sometimes called echoes or ringing) with varying amplitudes but similar spectral content around the best frequency of the measurement location. The coda is physiologically vulnerable, disappearing when the cochlea is compromised even slightly. The multicomponent sensitive response is not yet completely understood. We use a mathematical model to describe how the response at the point of excitation can be traced back to three sources. Surprisingly, the first BM response is due to a fast wave emergent from the point of excitation, reflected by the stapes and then repropagated (in amplified fashion) as a traveling wave back to the point of excitation; the second is due to a reverse, slow, traveling wave, which is likewise reflected at the stapes back to the measurement location by the stapes. The coda is also due to systematic (not random) perturbations of the organ of Corti properties. Implications for normal hearing and for the interpretation of otoacoustic emissions are discussed.
Accuracy of synchrony judgment between two pulses: Effects of variations in cochlear delay amount
Authors: Aiba Eriko , Tsuzaki Minoru , Nagata Noriko , Nakagawa Seiji
Published: May 2013

The cochlear delay shifts the arrival of lower-frequency components of an auditory signal slightly but systematically behind that of higher-frequency components. Therefore, even if all of the components of a complex tone physically begin simultaneously, their temporal relation is not preserved at the cochlear level. In our previous study, the accuracy of synchrony judgment was measured using two types of chirps (compensated and enhanced chirps) and a pulse. The compensated chirp had an increasing frequency pattern to cancel out the cochlear delay. An enhanced chirp had a delay pattern that enhances the assumed cochlear delay. The pulse had a usual cochlear delay at the auditory peripheral. As a result, the accuracy of synchrony judgment was the highest in the pulse and higher in the enhanced chirp than the compensated chirp, implying that there is an asymmetric aspect. The purpose of this study is to investigate how our auditory system processes this asymmetric aspect, and what amount of temporal collapse was tolerated. We also measured the accuracy of synchrony judgment using stimuli that reverse the cochlear delay (the higher-frequency components arrive behind the lower-frequency components), or enhance the delay of lower-frequency components up to 8 times.
Auditory evoked responses to a frequency glide following a static pure tone
Authors: Wang Wen-Jie , Tan Chin-Tuan , Martin Brett A.
Published: May 2013

In this study, we look at the auditory evoked response to a frequency glide following a static pure tone. A frequency glide is a frequency ramp with specific frequency change range (Δf) and duration (Δt). Frequency change rate (Δf/ Δt) and direction (increasing or decreasing frequency) of a glide are important cues for speech perception. P1-N1-P2 acoustic change complex (ACC) responses to increasing or decreasing frequency glides were observed in the recordings of normal hearing subjects. Subjects were also asked to behaviorally discriminate similar stimuli with a fixed Δt at 50 ms or 200 ms and a varying Δt in a separate experiment. Similar findings were obtained with glides at both 500 and 1 kHz base frequency. In these preliminary data, we observed larger N1-P2 responses with the glides of fixed Δt 50 ms at both 500 Hz and 1000 Hz base frequency. However, larger N1-P2 responses for increasing glides than for decreasing glides were only observed with glides at 500 Hz base frequency. Larger N1-P2 response at shorter Δt seems to tally with the smaller behavioral threshold of Δt difference between stimulus with a fixed Δt at 50 ms and stimulus with varying Δt.
Evidence for modulation rate specific adaptation in the frequency following response?
Authors: Gockel Hedwig E. , Krugliak Alexandra , Plack Christopher J. , Carlyon Robert P.
Published: May 2013

We used an adaptation paradigm to investigate whether the frequency following response (FFR) would show evidence for neurons tuned to modulation rate in humans, as has been previously shown in the inferior colliculus of the macaque using fMRI [Baumann et al. Nat. Neurosci. 14, 423–425 (2011)]. The FFR to a 100-ms, 75-dB SPL, target complex tone with an envelope rate of 213 Hz was measured for ten subjects. The target was preceded by a 200-ms, 75-dB SPL, adaptor complex with an envelope rate of 90, 213, or 504 Hz. All complexes contained alternating-phase harmonics from approximately 3.9 to 5.4 kHz. A “vertical” montage (+ Fz, - C7, ground = mid-forehead) was used, for which the FFR is assumed to reflect phase-locked neural activity from generators in the rostral brainstem. The results showed significant adaptation effects in the spectral magnitude of the 213-Hz envelope-related component of the FFR. However, the identical-rate adaptor did not generally produce more adaptation than the different-rate adaptors. Hence, the present results do not provide evidence for neurons tuned to modulation rate in the human brainstem. [Work supported by Wellcome Trust Grant 088263.]
Interactive behavior of internal resonators in acoustic metamaterials under impact pulse loading
Authors: Tan Kwek Tze , Sun C. T.
Published: May 2013

Acoustic metamaterials exhibit negative effective mass density when the lattice system consists of mass-in-mass microstructural units. It is found out that the effective mass density becomes frequency dependent and displays negativity for frequencies near the resonant frequency of the internal resonators. The effect of a negative mass property implies that stress wave propagation is prohibited; leading to structural applications like vibration control, impact protection, and shock wave mitigation. Under impact loading, internal resonators are revealed to effectively reduce the displacement/velocity of the overall structure, and attenuate a specifically designed range of frequency where the negative effective mass density is exhibited. However, researchers have yet to study the mutual interaction between the internal resonators. Knowing how adjacent resonators interact and response to dynamic profile of preceding resonators may lead to more efficient design for stress wave attenuation. In this paper, we performed detailed investigation on the interactive behavior of internal resonators in acoustic metamaterials under an impact pulse load. Finite element analysis results show that when internal resonators are adjacently placed, they produce a coupled resonance effect, resulting in a leakage of frequency just below the resonant frequency of the resonators. This frequency leakage can lead to energy storage and harvesting applications.
Acoustic double negativity with coupled-membrane metamaterial
Authors: Ma Guancong , Yang Min , Yang Zhiyu , Sheng Ping
Published: May 2013

Over the past decade, the emergence of acoustic metamaterials has considerably broadened the possibility of acoustic wave manipulations. Within this area, exotic effective constitutive parameters (mass density and bulk modulus) are a most hotly pursued topic, at the core of which is the realization of acoustic double negativity. Here, we show with experiments, simulations and homogenization that a single resonant structure can achieve acoustic double negativity. The metamaterial is comprised of two decorated elastic membranes, which are connected together by a rigid ring. Impedance measurement reveals that the system’s transport behavior is governed by the three eigenmode resonances in the sub-kHz regime, which are separately tunable via system parameters. Measured displacement profiles at the sample surfaces using laser vibrometer show that the system’s eigenmodes are, respectively, dipolar or monopolar in their nature. The simplicity of the metamaterial also enables us to retrieve its effective mass density and effective bulk modulus by performing homogenization. The results help explaining the physics behind the transport properties, and confirm that a double-negative passband is realized in a frequency range (around 500–800 Hz). Excellent agreement between experiments, simulations, and theory is achieved.
Conceal an acoustic sensor by using single-negative acoustic materials
Authors: Cheng Jianchun , Liang Bin , Zhu Xuefeng
Published: May 2013

A coordinate transformation scheme is proposed to make a sensor acoustically undetectable while allowing it to receive external information. The designed structure only comprises complementary media (CM) whose acoustic parameters are single-negative rather than double-negative, and are totally independent of those of the sensor and the background medium. The numerical results show that the incident wave can pass across the CM changelessly, and it is therefore reasonable to identify such a structure as an acoustic cloak which enables one to “hear without being heard.” Further, a nonlinear transformation scheme is developed, in an attempt to simplify the practical realization to the fullest extent. The designed multi-layered structure is formed by alternately arranging one single pair of CM with homogeneous isotropic single-negative parameters which are also totally independent of the sensor and background medium. The numerical results show that acoustic scattering from the sensor is suppressed considerably when the number of bilayers is large enough. The feasibility of designing acoustic cloaks by single-negative media and the flexibility in choosing the acoustical parameters of cloak may significantly facilitate the experimental realization of acoustic cloaks and promise new possibilities in a wide range of acoustics, optics, and engineering applications.
Experimental validation of the band-gap and dispersive bulk modulus behavior of locally resonant acoustic metamaterials
Authors: Reynolds Matthew , Gao Yan , Daley Steve
Published: May 2013

Over the last decade there has been significant interest in the design and production of acoustic metamaterials with physical qualities not seen in naturally occurring media. Progress in this area has been stimulated by the desire to create materials that exhibit novel behavior such as negative refraction due to negative material parameters, and band gaps in the frequency response of the material. An acoustic metamaterial is presented that consists of an acoustically transparent mesh with an array of split hollow spheres. Split hollow spheres are analogous to the split ring resonators found in many electromagnetic metamaterials and act as Helmholtz resonators providing a resonant band gap at low frequencies where achieving a Bragg gap would be impractical, and providing a dispersive effective bulk modulus that can become negative. Since an eventual goal of the work is to produce such materials on a micro-scale, the metamaterial is designed for, and produced using, 3D printing techniques (additive layer manufacturing). Results are presented for material comparing theory and experiment, and methods for increasing the bandwidth of the behavior in question are proposed, including a mixed resonator solution and the integration of active components into the material.
A meta-mass mechanical energy valve and battery---A key to vibration energy harvesting
Authors: McCoy Joh J.
Published: May 2013

A meta-mass comprised of a rigid housing element densely filled by a multiplicity of oscillators, is designed to act, when attached to a vibrating structure, as a one-way energy valve and mechanical battery. When the oscillators are joined with mechanical/electrical converters, the meta-mass becomes a vibration energy harvester that has a capacity that far exceeds harvesters comprised of a limited number of Newtonian mass elements. When viewed from the structure side of its attachment, the meta-mass device action as a one-way valve appears as an energy sink, such that when sufficiently strong initiates a transport process drawing energy from remote locations, thereby solving a fundamental aperture problem to energy harvesting, occasioned by the spatial diffuseness of the energy source. When viewed from the device side of the attachment, the meta-mass device action as a battery provides for the accumulation of mechanical energy, thereby solving a second fundamental problem to energy harvesting, occasioned by the arrival of the vibration energy as a sequence of weak packets. A meta-mass vibration energy harvester (MMVEH) is contrasted with the present art of vibration energy harvesters (VEH).
The cognitive basis of spontaneous imitation: Evidence from the visual world
Authors: Goldinger Stephen D.
Published: May 2013

It is well-established that, when people are asked to identify and quickly repeat spoken words, they show a strong tendency to spontaneously imitate the vocal and/or phonetic characteristics of the stimulus tokens. There is mixed evidence, however, regarding the underlying basis of such imitation: Does it only reflect gestural attunement (as in Direct Realism), or does it also reflect cognitive principles of word perception and memory? The gestural attunement view has face validity, as imitation seems to require tacit knowledge of other peoples’ articulatory actions. The role of memory is less obvious, although people can certainly imitate others from memory. In this talk, I will present evidence from three new experiments, pairing procedures from the “visual world” paradigm with a speech production task. Across studies, there is clear evidence that degrees of speech imitation are tightly connected to attention and memory processes that were engaged during initial exposure to spoken words. The results show clear imitation (in naming depicted objects), both with and without spoken words prompting responses, and show strong effects of competition among visual objects: Imitation increases when other potential objects have similar names, or even similar appearances. Spontaneous imitation is both a gestural and a cognitive behavior.
Phonetic convergence is not a consequence of stimulus-response compatibility
Authors: Mitterer Holger
Published: May 2013

Moving to a different region within a country/language area tends to have the same consequences all over the globe. Phonetic patterns change over time, and they change in the direction of the pattern in the environment [Harrington et al. (2000), Sancier and Fowler (1997)]. This has often been attributed to a basic stimulus-response compatibility on a gestural level [Galantucci et al. (2009)]. The experimental evidence for a gestural stimulus-response compatibility, however, invariably confounds gestural with phonological compatibility, that is, gesturally incompatible distractor stimuli are also from a different phonological category [Mitterer and Ernestus (2008)]. In this presentation, I will present three lines of evidence that question a gestural stimulus-response compatibility driving phonetic convergence. A first experiment shows that phonetic convergence does not necessarily target concrete phonetic detail, but rather more global and abstract parameters. Second, I will show that there is no relationship between the amount of phonetic stimulus-response overlap and response latency, the typical measure of stimulus-response-compatibility effects. Finally, I will present data that show that two participants in a conversation can maintain a marked phonetic difference. The combined evidence indicates that phonetic convergence is not driven by a gestural stimulus-response compatibility.
Evidence for an articulatory component of phonetic convergence from dual electromagnetic articulometer observation of interacting talkers
Authors: Tiede Mark , Mooshammer Christine
Published: May 2013

Speech audio and articulatory movements of age- and gender-matched speaker pairs have been recorded in face-to-face interaction using two electromagnetic articulometer (EMA) systems simultaneously. Speakers matched for language (AE:AE) were compared with mixed language backgrounds (AE:Spanish, AE:German). Tasks included synchronized, imitated, and spontaneous speech interspersed with repeated baseline utterances for evaluation of mutual accommodation. Euclidean distances (EDs) between vowel midpoint formant frequencies from the initial and final baseline tasks showed symmetric reductions associated with convergence which were larger for the speakers with the same language background. To test whether the observed reduction might be due to fatigue or repetition effects EDs were also calculated between AE speakers who did not participate in the same experiment. Because reduction was minimal for this comparison the possibility that convergence can be attributed to simple optimization is excluded. Kinematic and dynamic convergence was examined on coda velar gestures from the baseline tasks. EDs in peak velocity, sensor path distance, gesture amplitude, and stiffness computed between speakers all showed decreases consistent with convergence. Associated within-speaker differences showed that accommodation was effectively symmetric, and because the speakers moved towards one another the difference was not due to practice or fatigue effects. [Work supported by NIH.]
Visual enhancement of alignment to noisy speech
Authors: Dias James W. , Rosenblum Lawrence D.
Published: May 2013

Talkers imitate aspects of perceived speech; a phenomenon known as speech alignment. Previous studies have found that talkers will align not only to auditory speech, but also visual speech information. Furthermore, talkers who interact in full view of a conversational partner will align more than talkers who interact with a partner they can only hear [Dias and Rosenblum, Perception 40, 1457–1466 (2011)]. The purpose of the current investigation is to evaluate whether visual speech information increases speech alignment when the auditory speech is noisy. Participants shadowed (said out-loud) the utterances of a pre-recorded model presented under audio-alone or audiovisual conditions, either in noise (+10 db SNR) or in the clear. These shadowing tokens were then rated for their similarity (alignment) to the model’s tokens using a matching task performed by naïve raters. Despite word identification performance being the same across all conditions, participants aligned more to the model when listening to speech in the clear than speech in noise. Further, the addition of visual information enhanced alignment for words presented in noise, but not for words presented in the clear. These data suggest the availability of visual speech information can enhance speech alignment when shadowing in noise.
Reconciling diverse findings in studies of phonetic convergence
Authors: Pardo Jennifer
Published: May 2013

Phonetic convergence occurs both when individuals interact in conversation and when listeners rapidly repeat words presented over headphones. Results from multiple studies examining phonetic convergence offer an array of often confusing and disparate findings. Reconciling such diverse findings is difficult without a clear rationale for engaging in one acoustic measure over another. The current paper proposes a paradigm that models perceptual and acoustic measures together. Measures of multiple acoustic-phonetic attributes were compared with a perceptual measure of phonetic convergence in a shadowing study. Although convergence was not significant in any acoustic measure alone, the combination of acoustic attributes predicted perceived phonetic convergence on an item-by-item basis. Because perceptual measures integrate across multiple acoustic-phonetic dimensions, future studies of phonetic convergence should use perceptual tasks to calibrate the relative contribution of individual acoustic-phonetic parameters.