bluuebunny/crossref_metadata_2025 huggingface dataset:
Forced Response Analysis of a Mistuned, Compressor Blisk Comparing Three Different Reduced Order Model Approaches
Authors: Salas Mauricio Gutierrez , Bladh Ronnie , Mårtensson Hans , Petrie-Repar Paul , Fransson Torsten , Vogt Damian M.
Published: November 2016

Accurate structural modeling of blisk mistuning is critical for the analysis of forced response in turbomachinery. Apart from intentional mistuning, mistuning can be due to the manufacturing tolerances, corrosion, foreign object damage, and in-service wear in general. It has been shown in past studies that mistuning can increase the risk of blade failure due to energy localization. For weak blade to blade coupling, this localization has been shown to be critical and higher amplitudes of vibration are expected in few blades. This paper presents a comparison of three reduced order models (ROMs) for the structural modeling of blisks. Two of the models assume cyclic symmetry, while the third model is free of this assumption. The performance of the reduced order models for cases with small and large amount of mistuning will be examined. The benefits and drawbacks of each reduction method will be discussed.
Design of Compressor Endwall Velocity Triangles
Authors: Auchoybur Kiran , Miller Robert J.
Published: November 2016

The operating range of a compressor is usually limited by the rapid growth of three-dimensional (3D) separations in the endwall flow region. In contrast, the freestream region is not usually close to its diffusion limit and has little effect on overall range. In light of these two distinct flow regions, this paper considers how velocity triangles in the endwall region should be designed to give a more balanced spanwise failure across the span of a blade row. In the first part of this paper, the sensitivity of 3D separations in a single blade row to variations in realistic multistage inlet conditions and endwall geometry is investigated. It is shown that a blade's 3D separation size is largely controlled by the dynamic pressure within the incoming endwall “repeating stage” boundary layer and not the detailed local geometry within the blade row. In the second part of this paper, the traditional design process is “flipped.” Instead of redesigning a blade's endwall geometry to cope with a particular inlet profile into the blade row, the endwall region is redesigned in the multistage environment to “tailor” the inlet profile into downstream blade rows, giving the designer a new extra degree-of-freedom. This extra degree-of-freedom is exploited to balance freestream and endwall operating range, resulting in a compressor having an increased operating range of ∼20%. If this increased operating range is traded with reduced blade count, it is shown that a design efficiency improvement of ∼0.5% can be unlocked.
Parameter Identification of Permanent Magnet Synchronous Machine Based on an Adaptive Mutation Dynamic Differential Evolution
Authors: Wu Lianghong , Liu Zhao-Hua , Wei Hua-Liang , Zhong Qing-Chang , Xiao Xiao-Shi
Published: November 2016

The problem of parameter estimation of permanent-magnet synchronous machines (PMSMs) can be formulated as a nonlinear optimization problem. To obtain accurate machine parameters, it is necessary to develop easily applicable but efficient optimization algorithms to solve the parameter estimation models. This paper proposes a novel dynamic differential evolution with adaptive mutation operator (AMDDE) algorithm for the multiparameter simultaneous estimation of a nonsalient pole PMSM. The dynamic updating of population enables AMDDE to responds to any improved changes of the population immediately and thus generates better optimization solutions compared with the static mechanism used in original differential evolution. Two mutation strategies, namely DE/rand/1 and DE/best/1, are adaptively employed to balance the global exploration and local exploitation. The effectiveness of the proposed AMDDE is demonstrated on the multiparameter estimation for a nonsalient pole PMSM. Experimental results indicate that the proposed method significantly outperforms the existing peer algorithms in efficiency, accuracy, and robustness. Furthermore, the new algorithm can be potentially realized in digital microcontroller due to its simple structure and lower memory requirement. The proposed algorithm can also be applied to other parameter estimation and optimization problems.
Experimental constructions of binary matrices with good peak-sidelobe distances
Authors: Michel Jerod
Published: November 2016

Skirlo et al., in “Binary matrices of optimal autocorrelations as alignment marks” [J. Vac. Sci. Technol., B 33, 1 (2015)], defined a new class of binary matrices by maximizing the peak-sidelobe distances in the aperiodic autocorrelations and, by exhaustive computer searches, found the optimal square matrices of dimension up to 7 × 7, and optimal diagonally symmetric matrices of dimensions 8 × 8 and 9 × 9. The authors make an initial investigation into and propose a strategy for (deterministically) constructing binary matrices with good peak-sidelobe distances. The authors construct several classes of these and compare their distances to those of the optimal matrices found by Skirlo et al. Our constructions produce matrices that are near optimal for small dimension. Furthermore, the authors formulate a tight upper bound on the peak-sidelobe distance of a certain class of circulant matrices. Interestingly, binary matrices corresponding to certain difference sets and almost difference sets have peak-sidelobe distances meeting this upper bound.
Higher order acoustoelastic Lamb wave propagation in stressed plates
Authors: Pei Ning , Bond Leonard J.
Published: November 2016

Modeling and experiments are used to investigate Lamb wave propagation in the direction perpendicular to an applied stress. Sensitivity, in terms of changes in velocity, for both symmetrical and anti-symmetrical modes was determined. Codes were developed based on analytical expressions for waves in loaded plates and they were used to give wave dispersion curves. The experimental system used a pair of compression wave transducers on variable angle wedges, with set separation, and variable frequency tone burst excitation, on an aluminum plate 0.16 cm thick with uniaxial applied loads. The loads, which were up to 600 με, were measured using strain gages. Model results and experimental data are in good agreement. It was found that the change in Lamb wave velocity, due to the acoustoelastic effect, for the S1 mode exhibits about ten times more sensitive, in terms of velocity change, than the traditional bulk wave measurements, and those performed using the fundamental Lamb modes. The data presented demonstrate the potential for the use of higher order Lamb modes for online industrial stress measurement in plate, and that the higher sensitivity seen offers potential for improved measurement systems.
Improvement of the noisy speech recognition using method of thresholds and emphasizing wavelet coefficients for clean speech
Authors: Midorikawa Yoichi , Akita Masanori
Published: November 2016

In recent years, speech recognition under the noisy environment is one of the very important technologies. This study improves a speech recognition method for the signals under the noisy environment using method of thresholds and emphasizing wavelet coefficients for clean signal data. Noisy speech recognitions are extremely difficult problem. To analyze noise problem, in general, the majority of people have used the Fourier analysis. But the Fourier transform reveals only the frequency information. The general noise filters reduce specific frequency band contained both signal and noise. It is difficult to eliminate only noise component from a signal containing noise components. To overcome this difficulty, we applied the wavelet analysis. In this study, we improve the speech recognition under the noisy environment by bringing it close to reference data and noisy input data by modifying the spectrum by the wavelet transform using thresholds and emphasizing methods for reference clean speech data. We apply this method using wavelet transform to the modification of spectral envelope shape. As a result, noisy speech recognition rate is improved by this method using wavelet transform for clean speech data.
Investigation of vibration and noise characteristics in axial flux permanent magnet synchronous motor with different magnet shapes
Authors: Deng Wenzhe , Zuo Shuguang , Lin Fu , Wu Shuanglong
Published: November 2016

This paper investigates the vibration and noise characteristics of axial flux permanent magnet (AFPM) motor with different magnet shapes. A multiphysics model is developed to predict electromagnetic vibration and noise of AFPM motor which contains three steps. In the first step, nodal force exerted on the surface of stator tooth is calculated using 3D finite element method (FEM). Then, structural analysis is performed to investigate the structure natural characteristics and the nodal force calculated is mapped into structural model as the excitation in the second step. In the third step, the vibration and noise of AFPM motor are calculated through modal superposition method (MSM) and boundary element method (BEM) respectively. Vibration and noise characteristics of AFPM motor with different magnet shapes are investigated based on the multiphysics model. The results reveal that AFPM motor with sine-shaped magnet demonstrates lower noise level compared to AFPM motor with sector- or cylinder-shaped magnet.
Analysis of low frequency ocean ambient noise induced by internal wave in sand dune region of northern South China Sea
Authors: Wei Ruey-Chang , Chien Kuo-Feng , Chiu Linus Y.S. , Chen Chi-Fang
Published: November 2016

Most powerful internal waves in oceans were found in South China Sea, which were generated in Luzon Strait and mainly driven by tides. In past decades, researches of internal wave’s effects on ocean processes have been concentrated on the slope of continental shelf, where transformations of internal waves were significant, so were the induced phenomena. In recent years, large groups of underwater sand dunes were discovered along the upper continental slope, whose formation was speculated to be related to internal wave’s energy. In 2014, acoustical and oceanographic moorings were deployed in the sand dune region to study acoustical fluctuations due to the coupled effects of internal waves and sand dunes. Ocean ambient noise data were collected by four SHRUs (Several Hydrophone Recording Unit) and one VLA (Vertical Line Array) at different depths, analysis, and comparison of noise during internal wave events were presented in this study. Low frequency noises were generated by the passing of internal wave, in forms of agitations of sea surface, dramatic fluctuations of water column, and also strumming of mooring structure. Directivity of induced noise helps to identify the mechanism of source, and in addition spatial variation can show the influences from the topography of sand dune.
4-D ultrafast ultrasound imaging: in vivo quantitative imaging of blood flows and tissue viscoelastic properties
Authors: Pernot Mathieu , Correia Mafalda , Provost Jean , Papadacci Clement , Tanter Mickael
Published: November 2016

Very high frame rate ultrasound imaging has enabled the development of novel imaging modalities such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few. We present here the extension of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. High contrast and resolution were achieved while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32X32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 4-D Ultrafast Doppler Imaging, and 4D vector flow imaging. These results demonstrate the potential of 4-D Ultrafast Ultrasound Imaging for the volumetric real-time mapping of stiffness, tissue motion and flow in humans in vivo and promises new clinical quantitative applications of ultrasound with reduced intra- and inter-observer variability.
Pilot evaluation of histotripsy treatment for Peyronie’s disease
Authors: Wang Yak-Nam , Maxwell Adam D. , Brady Lynda , Schade George R. , Yasser Haider , Lee Franklin , Ledoux William R. , Bailey Michael R. , Wessells Hunter
Published: November 2016

Peyronie’s disease (PD) is a debilitating scarring disorder of the penis which can cause significant curvature, pain, and psychological distress. Intra-lesional injection of specialized drugs to break down the fibrous matrix demonstrates modest results and is extremely expensive; surgery remains the gold standard for PD despite possible complications. We evaluated the feasibility of using histotripsy to disrupt the fibrous plaque and alter the mechanical properties as a novel non-invasive treatment. Freshly excised Peyronie’s plaques (n = 5) were separated into individual samples for histotripsy treatment or control tissue. Treatments were conducted using a 1.0 MHz custom-built therapy transducer delivering pulses with repetition frequency of 1000 Hz, duty cycle 0.5%, and peak focal pressures of (98/-17 MPa) under ultrasound guidance. Tissue was either formalin fixed for histological evaluation or frozen for mechanical testing. Histotripsy induced disruption of collagen and elastin fibrils was evident in all fibrous portions of plaques. Histotripsy treatment produced decreased mean modulus, ultimate tensile strength, maximum load, and toughness vs. untreated control samples on mechanical testing. Additionally, the displacement to maximum load ratio was greater in treated vs. untreated control samples. [Work supported by NIH grants K01 DK104854, DK043881, EB007643, NSBRI through NASA NCC 9-58, and VA RR&D grant A9243C.]
Piezoelectric particle counter using the resonance vibration modes of a circular plate
Authors: Hayashi Masatoshi , Koyama Daisuke , Matsukawa Mami
Published: November 2016

In the field of environmental measurements, robust and simple sensors with no electric power supply are required. In the river, the size distributions of sand and small stones in river-bed are important factor for river disaster prevention. In this report, a passive piezoelectric sensor for measurement of the particle distribution in flow was investigated. The sensor consists of an aluminum circular plate (diameter: 50 mm; thickness: 2 mm) and an annular piezoelectric transducer (inner radius: 5 mm; outer radius: 10 mm). Alumina spheres with several diameters (φ = 3, 5, and 8 mm) were employed as small particles. When the particles hit the surface of the sensor, the flexural vibration is excited on the circular plate and the electric power is generated through the piezoelectric effect. Two main peaks at 16.3 and 66.7 kHz appeared in the output signal, and the ratio of these peaks depended on the particle size. From the finite element analysis, it was found that these frequencies of 16.3 and 66.7 kHz correspond with the fundamental and second resonance vibration modes. These results indicate that the particle size can be determined from the frequency spectrum of the output signal.
Time domain simulations of a novel lingual organ pipe construction
Authors: Rucz Péter , Nagy Nóra M. , Angster Judit , Augusztinovicz Fülöp , Miklós András
Published: November 2016

In a traditional pipe organ, the dynamic range of both labial (flue) and lingual (reed) pipe ranks are strictly limited as each rank is tuned and voiced to a nominal windchest pressure. Changing this pressure not only affects the amplitude of the radiated sound but both the pitch and the timbre of the pipes. A new pipe construction with a blown open free tongue was proposed recently to overcome this limitation. Prototype pipes of the new construction were built and measurements were carried out on them at different blowing pressures. It was found that the new construction provides a pleasing stability of the pitch and a broad range of playable amplitudes; however, the timbre of the pipes changes significantly with the blowing pressure. To improve the design in the latter aspect, a physical model of the pipes needs to be established first. In this contribution the sound generation of the experimental pipes is simulated by time domain computations. The resonator and its interaction with the vibration of the tongue are simulated using both the truncated impedance model and the reflection function approach. Results of the temporal simulations and their comparison with measurements are presented.
End-to-end music transcription using a neural network
Authors: Smaragdis Paris
Published: November 2016

We present various neural network models that learn to produce music transcriptions directly from audio signals. Instead of employing commonplace processing steps, such as frequency transform front-ends or temporal smoothing, we show that a properly trained neural network can learn such steps on its own while being trained to perform note detection. We demonstrate two models that use raw audio waveforms as input and produce either a probabilistic piano roll output or text in music notation format that can be directly rendered into a score.
Nestled in nature but near to noise—The Ford Amphitheatre
Authors: Hoover K. Anthony
Published: November 2016

The historic Ford Amphitheatre was relocated in 1920, from what would later become the location of the Hollywood Bowl, across the Hollywood Freeway, into an arroyo with a dramatic natural backdrop. The original wood structure was destroyed by a brush fire in 1929, and rebuilt in concrete in 1931. In the meantime, the freeway has become increasingly noisy. The current renovation to this 1200 seat outdoor amphitheatre includes an expanded “sound wall” that will help to mitigate freeway noise while providing optimal lighting and control positions. The remarkably uniform distribution of ambient noise throughout the seating area, the significantly reverberant character of this outdoor space, and the apparent contributions by the arroyo will be discussed, along with assorted design and construction challenges.
Impact of drift on the vehicle liftoff acoustic environments
Authors: Giacomoni Clothilde , Kenny R. Jeremy
Published: November 2016

During liftoff, a vehicle can drift due to wind, nozzle gimbaling, fly away maneuver, etc. This drift can cause the exhaust plumes to impinge on the deck and cause the noise levels experienced by the vehicle to increase. A small increase in the plume impingement can have a dramatic effect on the noise levels when the vehicle is only a few nozzle diameters from the deck. As the vehicle lifts off the deck the increase in noise levels lessens as the plume impingement increases. Several scale model acoustic tests have been undertaken at Marshall Space Flight Center which had test cases that were used to define the relationship between drift and the noise levels experienced by the vehicle.
Experimental validation of the underwater sound focusing properties of a pentamode gradient index metamaterial lens
Authors: Cushing Colby W. , Haberman Michael R. , Wilson Preston S. , Su Xiaoshi , Norris Andrew N.
Published: November 2016

A gradient index (GRIN) acoustic lens is a material slab with spatially varying properties that refracts an incident acoustic wave to produce a desired transmitted field. Hyperbolic secant index profiles have widely been used to create focusing lenses with minimal aberration and good sidelobe suppression. This work reports on the underwater experimental characterization of a GRIN lens that employs a modified secant profile for improved aberration reduction when compared to the hyperbolic secant profile. The index profile is produced using a two-dimensional pentamode material created from air-filled aluminum hexagonal unit cells. The lens is fabricated from waterjet cut aluminum plates that are stacked and sealed together. The test apparatus is comprised of a custom plane-wave source, an automated horizontal planar scanner, a pentamode GRIN lens, a custom support structure, and a calibrated hydrophone and associated electronics. The source was tested for amplitude planarity across its aperture at a constant distance to confirm its usability for this system. Experimental results of lens performance over the frequency range of 10-40 kHz are compared with the isolated source and model predictions. [Work supported by ONR.]
Metamaterials made of granular chains for nondestructive evaluation applications
Authors: Rizzo Piervincenzo , Nasrollahi Amir
Published: November 2016

In the last two decades it has been demonstrated that highly nonlinear solitary waves (HNSWs) propagating in metamaterials made of chains of granular particles can be used in many physics and engineering applications, including acoustic lenses, impurity detectors, and nondestructive evaluation (NDE). HNSWs are compact nondispersive waves, and in this paper, we demonstrate their application for the nondestructive evaluation of civil, mechanical, and aerospace structures. In particular, this presentation delves with the non-invasive assessment of concrete strength and the evaluation of thermal stress in slender beams. For the concrete application, the NDE method exploits the dynamic interaction between the metamaterial and the concrete, and the hypothesis is that this interaction depends on the stiffness of the specimen being inspected. The results show that the time of flight of the HNSWs is inversely proportional to the modulus of elasticity of the concrete. For the buckling application, we present the coupling mechanism between a beam and the HNSWs propagating along a straight granular chain in contact with the beam. We show that the waves can be used to measure the stress of thermally loaded structures or to infer the neutral temperature, i.e., the temperature at which this stress is null.
Language contact and accent changes in Japanese
Authors: Kubozono Haruo
Published: November 2016

This talk discusses how word accent patterns of regional Japanese dialects have changed over the years as they were heavily exposed to standard Tokyo Japanese. A particular attention is paid to the accent changes that have taken place in Kagoshima Japanese, a southern dialect whose accent system is strikingly different from that the standard variety. Original fieldwork studies show that this regional dialect has been heavily influenced by the standard variety with respect to the presence or absence of a pitch fall, while the position of the fall is still determined by its traditional system: e.g., /doo.na.TU/ → /doo.NA.tu/ “donut” (Tokyo form: /DOo.na.tu/). Interestingly, the same mechanism is at work when (Tokyo) Japanese borrow words from English as loanwords: the recipient language copies the presence or absence of a pitch fall from the host language but it follows its own accent rule with respect to the position of the fall, e.g. /ba’.na.na/ “banana,” /wa.shi’n.ton/ “Washington.” These observations indicate that native Japanese speakers are highly sensitive to the presence or absence of a pitch fall when listening to a foreign language and a different variety of their native language, but are quite insensitive to the position of the pitch change.
Introduction to sparse and compressive sensing
Authors: Gerstoft Peter
Published: November 2016

Compressed sensing or sparse sampling is a signal processing technique for efficiently acquiring and reconstructing a signal, by finding solutions to underdetermined linear systems. I will describe the basic features of compressive sampling that has many opportunities in acoustics.
Long-term passive acoustic monitoring of Western Australian cockatoos
Authors: Madhusudhana Shyam , Erbe Christine
Published: November 2016

Carnaby’s black cockatoos (Calyptorhynchus latirostris) and forest red-tailed black cockatoos (Calyptorhynchus banksii naso) are threatened avian fauna endemic to Southwestern Australia. Both species vocalize during various activities including flight, foraging, feeding, and breeding, and their vocalizations are known to differ by age and gender. In this study, passive acoustic monitoring is employed to assist with ongoing monitoring and recovery efforts. Autonomous acoustic recorders are installed at two locations—an urban setting in the Swan coastal plains and a bushland setting in the Perth hills district. The urban setting is a well-known roosting site for Carnaby’s cockatoos. Noise from frequent aircraft activity is a dominant feature at the bushland setting. Call repertoires, established using visual sighting information, are used in developing automatic recognition algorithms for efficient processing of long-term recordings. In addition to providing information on population estimates, distribution, and demographics, the project aims to study the differences in call characteristics between the urban and bushland settings and establish a framework for observing potential seasonal changes in calling behavior.
Attenuation and dispersion of ultrasound in cancellous bone. Theory and experiment
Authors: Pakula Michal
Published: November 2016

The paper presents theoretical and experimental issues related to modeling of elastic wave propagation in cancellous bone. The Biot’s theory, commonly used for modeling of ultrasonic wave propagation in cancellous bone, is discussed in context of its potential applicability for theoretical prediction of wave parameters. Particular attention is focused on the analysis of physical mechanisms of ultrasonic wave propagation in cancellous bone that govern phase velocity and attenuation coefficient as function of frequency and porosity. The analysis of the model is focused on the absorption and scattering mechanisms responsible for attenuation of ultrasonic waves in cancellous bone, which based on the ultrasonic experiments presumably play a predominant role in the total attenuation. The suitability of the model is discussed and verified by comparison of results of sensitivity analysis of the model with experimental ultrasonic data for bone mimicking phantoms and human cancellous bones.
A design of broadband constant beam pattern transducers
Authors: Huang Dehua
Published: November 2016

A constant beam pattern (CBP) transducer is an acoustic transducer, where its beam patterns are independent of frequency. The theory and numerical simulations for constant beam pattern transducer design are introduced. For a hemispherical design, if the radial velocity distribution on the surface of a conventional hemisphere transducer is a single complete Legendre polynomial, the far field angular beam pattern shows the same Legendre polynomial distribution for all frequencies above its cut-off frequency, based on spherical Hankel function asymptotic approximation to the solutions from Helmholtz wave equation. Because of orthogonality, Legendre polynomials form a complete set, per Sturm-Liouville theory that an arbitrary velocity shading function can be expanded by Legendre series. Each polynomial within this Legendre series contributes its share to the far field, such that the converging acoustic beam pattern displays the same shape as the original shading function itself. Numerical simulations with various samples include (cos(theta))^3 and Gaussian, a well as equal sidelobe suppression classic Dolph-Chebyshev functions used as shading and achievable as beam patterns for a broadband frequency range.
Experimental modal analysis/synthesis of saxophone input impedances
Authors: Maestre Esteban , Scavone Gary P.
Published: November 2016

We present an experimental modal analysis/synthesis framework for the accurate modeling and efficient digital simulation of saxophone input impedances. Starting from impedance measurements, we perform spectral-domain modal analysis by iteratively minimizing the error between measurements and synthetic impedance responses. Synthesized impedances are formulated as passive digital filters in parallel form, enabling the construction of passive digital reflectances with potential use for efficient sound generation via coupling to a reed non-linear model. In this talk, we provide an overview and discuss our ongoing developments, pointing toward future directions in using this technique for real-time sound synthesis.
The benefits of cochlear implants for single-sided deafness for sound localization with multiple concurrent sources
Authors: Bernstein Joshua G. , Schuchman Gerald I. , Stakhovskaya Olga A. , Rivera Arnaldo L. , Brungart Douglas S.
Published: November 2016

Individuals with single-sided deafness (SSD) who receive a cochlear implant (CI) realize some benefit for localization and speech perception in noise. Previous studies of SSD-CIs examined simple conditions involving speech perception in the presence of a single noise masker or single-source localization. However, some of the most important benefits of two ears arise in multisource situations where binaural cues and head turning can facilitate the perceptual separation of spatial separated sources. Eight SSD-CI listeners performed a sound-localization task in a multisource environment pre-implantation and at least 3 months post-implantation. Environmental sounds were presented from a spherical loudspeaker array. The target sound was presented alone, or concurrently with one or three additional sources. The target was cued by being added to or removed from the mixture after a 6-s delay. A head-mounted tracker monitored head movements during the task. The CI substantially improved localization accuracy, reducing the mean azimuthal error by as much as 34%, while reducing the amount of head turning by as much as 44%, even during periods when the target sound was not present. For SSD-CI listeners, bilateral auditory input can improve environmental-sound localization in a complex mixture, while reducing the amount of head-turning effort required. [The opinions and assertions presented are the private views of the authors and are not to be construed as official or as necessarily reflecting the views of the Department of Defense.]
Recent progress in coastal acoustic tomography
Authors: Kaneko Arata , Syamsudin Fadli , Adityawarman Yudi , Zheng Hong , Huang Chen-Fen , Taniguchi Naokazu , Zhu Xiaohua , Lin Ju , Gohda Noriaki
Published: November 2016

Coastal acoustic tomography (CAT) which was proposed by Hiroshima University in 1990s as a shallow-sea application of ocean acoustic tomography (OAT) is developed as a mirror-type CAT (MCAT) for measuring deep strait throughflows in Indonesian archipelago seas in real time. MCAT system is composed of a land station (M0) connected to a 100 m submarine cable edged by a 5 kHz subsurface transceiver and triangular-arrayed bottom-moored stations (M1, M2, and M3). Reciprocal data are first obtained among three station pairs (M1M2, M2M3, and M3M1). Data received at M1 from M2 and M3 are transferred to the land station (M0) by the first mirror reflection, resulting in travel time summations (t21 + t10, t31 + t10) (t21: travel time from M2 to M1). Data obtained at the offshore stations M2 and M3 are transferred to the nearshore station M1 by the first mirror reflection, resulting in travel time summations (t12 + t21, t13 + t31, t23 + t31, and t32 + t21). All the first mirror data at M1 are also transferred to M0 by the second mirror reflection, adding a travel time by t10 for the above four travel time summations. Finally, travel time differences are calculated for M0M1, M1M2, M2M3, and M3M1 by subtracting the summation data at M0. They are converted to path-average currents along the four transmission lines, succeeding in strait throughflow estimate. The mirror reflection function of MCAT can develop in an underwater transfer system of sound from moving sources by adding a hydrophone.
Machine classification of P1-N1-P2 responses elicited with a gated syllable
Authors: Morris David J. , Klerke Sigrid
Published: November 2016

Onsets are generally considered to play an important role in the determination of syllable identity by human listeners. We measured P1-N1-P2 event-related potentials (ERP) from subjects (n = 11) in response to the syllable [sdʁə]. The complex onset of this syllable was sequentially gated at the consonant boundaries to yield three distinct tokens. Group ERPs to the three tokens were most different within a narrow latency window around 160 ms. This latency corresponded approximately to the lower portion of the ensemble N1-P2 deflection. Single-trial samples from the vertex channel at a range of poststimulus latencies around this point were submitted to multi-class classification by a support vector machine. The three tokens were used as class labels in a one-versus-one machine with a radial basis function kernel. Classification was trained and tested on subsets of the ERP data, and precision was found to be significantly better than chance. As the auditory stimuli used in this experiment differed only in initial consonant, these results indicate that syllable onset information is borne in the N1-P2 vertex response. They also demonstrate that a machine learning algorithm may be useful in retrieving syllable identity from single-trial ERP data.
Outer hair cell function in human ultrasonic perception
Authors: Okayasu Tadao , Nishimura Tadashi , Yamashita Akinori , Saito Osamu , Yamanaka Toshiaki , Hosoi Hiroshi , Kitahara Tadashi
Published: November 2016

Ultrasound can be heard by bone conduction. It is hypothesized that this bone-conducted ultrasound (BCU) is perceived in the basal turn of the cochlea and is a result of direct ultrasonic stimulation of inner hair cells via basilar membrane vibrations without cochlear amplifier. In order to clarify the contribution of outer hair cell function to ultrasonic perception, the present study evaluated changes in hearing sensitivity for BCU and air-conducted audible sound before and after ototoxic treatment. Twenty participants (40 ears) who were undergoing chemoradiation therapy with cisplatin participated in this study. After the treatment, 62.5% ears were diagnosed with hearing loss according to the criteria of the American Speech-Language-Hearing Association. The reduction of sensitivity to air-conducted audible sound occurred in the high-frequency range, which is thought to be important for ultrasonic perception. Surprisingly, BCU sensitivity was significantly improved after the treatment. These results suggest that direct ultrasonic stimulation of the cochlea, without audible sound generation, induces ultrasonic perception. The improvement of BCU sensitivity following the cisplatin administration may be explained by hypersensitivity associated with outer hair cells’ disorder.
High-pass filtering obscures stimulus encoding characteristics of the auditory brainstem response: Evidence from click and tone stimuli
Authors: Tabachnick Alexandra R. , Toscano Joseph C.
Published: November 2016

The auditory brainstem response (ABR) is an electrophysiological measure of early auditory processing. While previous work has examined ABRs to clicks, tones, speech, and music, it remains unclear how changes in acoustic properties (e.g., frequency) map onto specific changes in ABR components. This may be partly due to filtering during data processing. High-pass filtering can severely distort cortical and subcortical responses, potentially obfuscating how stimuli are encoded. To address this, we measured ABRs to a wide range of pure tones (250 to 8000 Hz) and examined how high-pass filtering affects tone- and click-evoked ABRs. In Experiment 1, various high-pass filter settings (0.1-300 Hz) were applied to click-evoked ABRs. In Experiment 2, ABRs to brief tones across a six-step frequency continuum were collected, and the same high-pass filter settings were applied. Results indicate that excessive high-pass filtering diminishes the amplitude of ABR components, consistent with previous findings. In addition, filtering can obscure true effects of stimulus frequency. With appropriate filters, we find that the amplitude of wave V tracks stimulus frequency log-linearly, demonstrating that tonotopic organization is preserved and easily detectable early in processing. Future ABR work should minimize the use of high-pass filters when studying the encoding of acoustic information.
Comparison of brainstem frequency-following responses associated with auditory streaming based on spectral and temporal cues
Authors: Yamagishi Shimpei , Otsuka Sho , Furukawa Shigeto , Kashino Makio
Published: November 2016

With the ABA streaming paradigm (van Noorden, 1975), Yamagishi et al. (2016) used spectrally differing A and B tones and showed that the auditory brainstem frequency-following response (FFR) to the second A tone co-varied with the perceived auditory stream. This study examined whether this effect is specific to the case in which the streaming is based on the spectral cues. We compared stream-perception-related FFRs between ABA stimuli based on spectral and temporal cues. In the spectral condition, the A and B tones differed in frequency (315 and 400 Hz, respectively). In the temporal condition, the stimulus consisted of sinusoidally amplitude-modulated 4-kHz tones that had identical long-term excitation patterns but differed in modulation frequency (60 and 170 Hz, respectively). We analyzed the spectral amplitudes of the FFRs at the stimulus frequencies for the spectral condition and those at the stimulus modulation frequencies for the temporal condition. We found that the FFR amplitudes to the second A tone generally tended to be larger in the two-stream percept than in the one-stream one for both the spectral and temporal conditions. This result implies that the mechanism responsible for the stream-perception-related FFR is common across cue domains.
Sound radiation from a fluid-loaded and elastically coated infinite plate with attached periodically located inhomogeneities
Authors: Zhang Yanni , Pan Jie , Huang Hai
Published: November 2016

An analytical model is developed for evaluating the sound radiation characteristics of a fluid-loaded and elastically coated infinite plate attached with periodically located inhomogeneities. The vibration and sound responses of such a periodic structure under a local excitation are obtained through wavenumber transformation method. The radiation characteristics of the plate are investigated via comparing with those of a plate with a single inhomogeneity and one without inhomogeneities. Three interesting features of the sound radiation are observed, which are related to plate’s global resonant modes, local resonances of the trapped modes formed around each inhomogeneity, and the band-pass characteristics of the periodicity, respectively. These features are explained by the variation in the surface supersonic wavenumber components and the waveguide properties of the fluid-loaded composite plate and the coherent resonance of all inhomogeneities.
A double-Nearey theory of vowel normalization: Approaching consensus
Authors: Whalen D. H.
Published: November 2016

Terry Nearey has provided substantial data and insights into the realm of speech perception throughout his career. A major concern of his is to reconcile seemingly contradictory results. Here, his double-weak theory of perception and his probabilistic sliding template model (PSTM) are examined in relation to vowel normalization. Various algorithms achieve good results, but they must all confront the contradiction in behavior: We normalize the speech of others but we can also tell when they use a (slightly) different vowel than we do. Thus, listeners are (as in double-weak theory) fairly accommodating of different vocal tracts, but, contrarily, they can hear differences as well. PSTM may account for this difference, if deviations from theory-predicted vowel location are just those that speakers identity as being different; this remains to be tested. The various sources of vowel information (lower formants, F0, higher formants, spectral tilt) interact in complex ways, as shown in Nearey’s work and others’. No theory is comprehensive yet, as acknowledged by Nearey himself. He has also made the observation that our theories of speech perception ought to perform at least as well as automatic speech recognition systems. Although we have not reached that stage, Nearey’s work brings us closer.
Modeling and simulation technique for development of multibeam echo sounder
Authors: Jung Dong Hwan , Kim Jea Soo , Byun Gi Hoon
Published: November 2016

Multibeam echo sounder (MBES) is commonly used for rapid sea floor mapping. We present a time-domain integrated system simulation technique for MBES development. The simulation and modeling (M&S) modules consist of four parts: sensor array signal transmission, propagation and backscattering modeling in the ocean environment, beamforming of the received signals, and image processing. Also, the simulation employs a ray-theory-based algorithm to correct the reconstructed bathymetry, which has errors due to the refraction caused by the vertical sound velocity profile. The developed M&S technique enables design parameter verification and system parameter optimization for MBES. The framework of this technique can also be potentially used to characterize the seabed properties. Finally, typical sea floor images are presented and discussed.
The noise of rock n’roll: Incidental noise characterization of underwater rock placement
Authors: Portugal Rute , Cheong Sei-Him , Brocklehurst James , Evans Breanna
Published: November 2016

Underwater noise is a growing concern to conservation and stock management efforts to which supra-national organizations (e.g., OSPAR or the European Union) and governments (e.g., USA) are beginning to respond by building catalogues of the noise introduced in the marine environment by human activity. Rock placement is a construction activity for which there is scarcely any data available. In order to fill the knowledge gap, opportunistic recordings were taken while the Gardline Mk 3 hydrophone array was deployed for Passive Acoustic Monitoring and mitigation for marine mammals. The recordings were analysed for their spectral and temporal characteristics, a correlation analysis between the amount of rock placed and the intensity of sound produced was made and the suitability of the hydrophone array for the collection of this type of data was assessed.
Stochasticism in noise generated by an array of marine hydrokinetic devices
Authors: Hafla Erin C. , Johnson Erick , Roberts Jesse
Published: November 2016

Marine hydrokinetic (MHK) devices generate electricity from the motion of tidal and ocean currents and ocean waves and provide another source of renewable energy. Additionally, MHK devices are also a new source of anthropogenic noise in the marine ecosystem and must meet regulatory guidelines that mandate a maximum amount of noise that may be generated. In the absence of measured levels from in-situ deployments, a model for predicting the propagation of sound from an array of MHK sources in a real environment needs to be established. A 3D finite-difference, time-domain solution to the governing velocity-pressure equations is used, which permits a finite number of complex sources and spatially varying sound speeds, bathymetry, and bed composition. However, deterministic solutions to these types of problems cannot capture uncertainties in the source profiles that may result from operational changes. This work presents the broadband sound pressure levels from an array of MHK sources as the amplitude and frequency from each source are allowed to vary. This Monte Carlo approach demonstrates that the idealized, deterministic solution, vastly underestimates the compounding uncertainty on the final sound field and that these small variations in the source profile cannot be ignored.
Acoustic ground truthing of airgun noise in Chatham Rise, New Zealand
Authors: Cheong Sei-Him
Published: November 2016

Underwater noise is a growing concern to conservation of the marine life. Noise generated by seismic survey in particular is recognised as a significant and pervasive pollutant, with the potential of impacting the marine ecosystem. Between the 1st February and 21st March 2016, a geophysical research survey was conducted in Chatham Rise, New Zealand, to collect seismo-acoustic data using a Sercel Sentinel seismic streamer in order to ground truth the underwater noise impact assessment, conducted according to the Department of Conservation (New Zealand) 2013 Code of Conduct. Data were analyzed in order to determine the received sound level at a distance up to 3 km from the seismic source array. This paper establishes the method to predict the mitigation impact radii from seismic data in order to validate the results obtained based on predictive noise modelling using Gardline 360M model. The study was also aimed to provide confidence to the capability of predictive modeling for estimating the acoustic impact zone of a seismic sound source. Data showed that seabed reflection can fluctuate significantly according to sediment topography and other environmental influences; however, a very consistent trend can be obtained from direct propagation to confidently establish mitigation radii. Results show that the employment of a seismic streamer for the establishment of effective mitigation radii is technically feasible and may be used as a tool to ground truth predictive modelling as part of a marine mammal mitigation plan.
A new metric to predict listener envelopment based on spherical microphone array measurements and ambisonic reproductions
Authors: Dick David A. , Vigeant Michelle C.
Published: November 2016

The objective of this work is to propose a new metric for listener envelopment (LEV), the sense of being immersed in a sound field. Current LEV metrics, for example, Late Lateral Energy Level (LJ), are based only the late sound field. However, recent studies indicate that the late component of the impulse response (IR) alone is inadequate for predicting LEV. For this study, room IR measurements were obtained with a 32-element spherical microphone array in a total of nine halls ranging from 400-2500 seats. A subset of these IRs were selected for a subjective listening test and processed for 3rd order Ambisonic reproduction over a 30-loudspeaker array. Two sets of modified IRs were also generated for the listening test by combining parts of IRs from different halls and by bandpass filtering to select certain frequency ranges, respectively. The ambisonic IRs were convolved with anechoic orchestral recordings and subjects rated the perceived LEV for each stimuli. The IRs were also analyzed objectively via plane wave decomposition (PWD). Energy from the PWD as a function of time, frequency, and arrival direction was correlated with the subjective LEV ratings to develop the new metric. [Work was supported by NSF Award 1302741.]
Characterization of the acoustic quality of classrooms in a music education facility
Authors: Vergara Erasmo F. , Paul Stephan , Brandão Eric , Marros Fernanda
Published: November 2016

Classrooms of a music education facility were characterized by the user by means of a questionnaire study and by acoustic impulse response measurements and subsequent calculation of reverberation time, definition, and other room acoustics parameters. The questionnaire study enabled to understand the preferences of students and music teachers regarding the acoustic quality of a total of twenty rooms for music practice and teaching. It was observed that preference for a certain room also depends on the instrument mostly played by the user. Three study rooms and three collective classrooms were the most cited ones and these have been evaluated according to ISO 3382. Opinions of the musicians showed to be coherent with the measurement data as the rooms considered to be dry had reverberation times around 0.3 seconds, and the rooms considered to be reverberant had reverberation times around 1.5 seconds. The six classrooms that were characterized as clear and well defined rooms, showed values for Clarity around 1 dB for live rooms and 14 to 22 dB for dry rooms. Definition remained above 43% for all rooms with Central Time below 24 ms for clarity rooms and less reverberant, and above 98 ms for the live rooms.