bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of atmospheric nonstationarity on models of low-frequency surface wind noise
Authors: Lyons Gregory W.
Published: June 2017

Measurements of sound propagation in the atmosphere are often limited by wind noise, particularly at low frequencies. The spectrum of wind noise at the ground surface, i.e. turbulent static pressure, can be modeled by the dominant shear-turbulence mechanism within the atmospheric boundary layer. This model assumes statistically-stationary boundary-layer turbulence, and as in the atmospheric sciences, quasi-stationarity is hypothesized to justify the assumption. However, this hypothesis is not uniformly valid, due to the diurnal cycle and large-scale atmospheric dynamics, and should be tested. This study applies several existing tests of nonstationarity to atmospheric measurements from a field experiment near Laramie, Wyoming and characterizes their relevance to simultaneous recordings of wind noise by flush-mounted infrasound sensors. By estimating the parameters for a mirror flow model of boundary-layer turbulence from the anemometer records, surface pressure model spectra are compared with the experimental wind noise. The performance of both the atmospheric turbulence and wind noise models are assessed with respect to each nonstationarity test.
An atmospheric turbulence model plugin for the NASA auralization framework
Authors: Aumann Aric R. , Rizzi Stephen A.
Published: June 2017

Temporal and spatial fluctuations in wind and temperature affect sound propagation causing both amplitude and phase modulations, or scintillations. The amplitude modulations can be heard, e.g., when listening to a distant aircraft. The phase modulations cause additional decorrelation between different propagation paths. NASA has been developing a software framework for the purposes of auralizing sound. The framework allows users to synthesize aircraft noise at a moving source and propagate it to a listener. This propagation occurs in the time domain through the application of gain, time delay, and filters. The framework includes a plugin architecture for rapid integration of new modules. A model has been developed to simulate the scintillation effects of acoustic propagation through a turbulent atmosphere. Further, this model has been implemented as a plugin to the NASA auralization framework. The turbulence model plugin generates a time-varying filter along each propagation path that describes the frequency dependent amplitude and phase modulations. The framework converts the filter descriptions to finite impulse responses, which are appended to other propagation filters, including atmospheric absorption and ground impedance. Because real scintillations can be heard, inclusion of the model is demonstrated to result in higher fidelity auralizations than those generated without the model.
Numerical analysis of atmospheric sound propagation in the littoral zone
Authors: Turo Diego , Ryan Teresa J. , Vignola Joseph F.
Published: June 2017

The propagation of sound over long distances is subject to many effects that are deemed negligible over short distances or in situations where idealized estimates are sufficient. This work describes a numerical model of acoustic propagation in littoral zone. The model therefore must include such effects for the purpose of investigating transmission loss during long-range propagation over the complex sea surface. Prior work by the investigators has presented the basic approach, which is a Crank-Nicolson parabolic equation that accounts for surface geometry, spreading loss, wind, and ground impedance. That work evaluated moderated propagation distances (up to 500 meters) and used a uniform temperature distribution. The current work will investigate considerations required for adding a temperature gradient component to the numerical model and explore the sensitivity of transmission loss to temperature gradient.
A quantitative ultrasound method to estimate dental implant stability
Authors: Vayron Romain , Nguyen Vu-Hieu , Bosc Romain , Haiat Guillaume
Published: June 2017

Dental implants are widely used clinically. However, implant failures, which may have dramatic consequences, still occur and remain difficult to anticipate. Accurate measurements of implants biomechanical stability are of interest since they could be used to improve the surgical strategy. The aim of this paper is to determine whether quantitative ultrasound can be used to determine dental implant stability. Firstly, an implant was initially completely inserted in the proximal part of a bovine humeral bone sample. The 10 MHz ultrasonic response of the implant was then measured and a quantitative indicator was derived. Then, the implant was unscrewed by 2π radians and the measurement was realized again. The value of indicator significantly increases as a function of the number of rotation. The results show that bone quantity in contact with the implant has a significant influence on its ultrasonic response. Secondly, a 3D finite element model was employed and the geometrical configuration was assumed to be axisymmetric. The numerical results show that the implant ultrasonic response changes significantly when a liquid layer is located at the implant interface. This study paves the way for the development of an ultrasonic tool to be used for the monitoring of osseointegration.
The influence of the synthesis parameters of nanoporous composite on the sound absorption coefficient
Authors: Ristanovic Ivana , Maricic Aleksa , Sumarac Pavlovic Dragana , Mijic Miomir
Published: June 2017

Metal materials with nanopore structure have multifunctional properties, they retain some properties of metal and also possess the characteristics of porous structures such as good sound absorption. This paper investigates the sound absorption characteristics of porous metal composites obtained by the mechanical mixing of polycrystalline powders. The mixture consists of (100—x) % Cu i x % Zn, (1≤ x ≤5). During the sample preparation process, several parameters were varied: activation time in the planetary mill in the non-oxide environment, pressing duration of activated powders and different sintering times of samples on the specific sintering temperature. Depending on the activation time, nanopowders with different sizes of nanocrystals are obtained. The activated powders were pressed into disk-shaped samples of different thickness, with a diameter of 30 mm. The normal incidence sound absorption coefficient of sintered samples was measured in an impedance tube. The obtained results showed that this material possesses very good absorption properties. These results can lead us to the conclusion that this kind of porous material may be potentially used for some specific absorber applications.
Effect of a unidirectional compression on sound absorbing properties of porous materials
Authors: LEI LEI , Dauchez Nicolas D. , Chazot Jean-Daniel
Published: June 2017

The addition of acoustic shields in the engine bay has shown the potential of reduction of powertrain exterior noise in the automotive industries. These shields are usually made by several layers of thermo-compressed porous materials. Some researches concerning the effect of compression on the acoustics properties of porous materials can be found in the literature. The effect of compression has been taken into account in the Biot-Allard model by modifying the physicals parameters (porosity, resistivity, tortuosity characteristic lengths,) versus to the compression rate n, defined as the ratio between nominal and compressed thickness. However, these laws are pointed out to be limited to a low compression rate (n<2). In our work, the compression rate can be attended to 10 for a porous material. New analytical laws are derived from the literature for the above mentioned physicals parameters. The static thermal permeability is also given as a function of compression rate in this paper. These laws take into account microscopic geometric changes, in particular the angular distribution of the fibers for fibrous type materials. A good agreement is obtained between direct measurements and the proposed laws for each parameters and absorption coefficient at normal incidence for a glass fiber and a melamine foam.
Physiologically motivated individual loudness model for normal hearing and hearing impaired
Authors: Pieper Iko , Mauermann Manfred , Oetting Dirk , Kollmeier Birger , Ewert Stephan D.
Published: June 2017

One consequence of sensorineural hearing loss is an altered loudness perception with a typically steeper progression of loudness as a function of stimulus level (loudness recruitment). Existing loudness models aim to explain altered loudness functions in hearing impaired (HI) effectively by means of an attenuation and compression component. Here the physiologically motivated loudness model of Pieper et al. [J. Acoust. Soc. Am. 139, 2896 (2016)] which simulates the nonlinear inner ear mechanics (transmission-line model, TLM) is used and extended to help distinguishing the role of peripheral factors, like damage to the outer hair cells (reduction of cochlear gain), and higher stages of auditory processing on loudness perception. Individual hearing thresholds were simulated by cochlear gain reduction in the TLM and linear attenuation (damage of inner hair cells) prior to an internal threshold. Hearing threshold and cochlear gain loss were estimated from individual loudness scaling data for narrowband noise. It was demonstrated that existing loudness models fail to predict individual loudness functions for HI. The current model showed better agreement with the data and accounted for individual loudness functions in HI and normal hearing using a linear weighting above the internal threshold (referred to as post gain).
An investigation of selective attention for roughness and loudness
Authors: Tan Alison , Berg Bruce G.
Published: June 2017

A novel method for measuring selective attention to different perceptual dimensions in a discrimination task is evaluated. The standard consists of three equal-intensity tones centered at 1000 Hz with 10 Hz separations. The signal is an intensity increment for the central tone. Discriminations can be based on either differences in loudness or roughness. In three conditions, listeners are instructed to attend to roughness when the signal and standard are adjusted to have the same energy, attend to roughness without the equal-energy constraint, or attend to loudness. Compliance to instructions is assessed by adding small level perturbations to stimuli and estimating a set of decision weights. Theoretically, attention to loudness yields three positive weights with equal magnitude, whereas attention to roughness yields a positive weight for the central tone and negative weights with half the magnitude for the two side tones. Estimated weights In the loudness and equal-energy roughness conditions are consistent with model simulations. In the roughness condition without equal-energy, the patterns of decision weights are a linear combination of the two other sets, indicating that listeners have difficulty in attending exclusively to the roughness cue in the presence of a valid intensity cue.
Effect of ossicular-joint flexibility on bone conduction hearing—A finite-element model analysis
Authors: Guan Xiying , Puria Sunil
Published: June 2017

The mammalian ossicular chain contains three distinct bones typically connected by synovial joints, comprising of a flexible coupling path between the eardrum and cochlea. It is hypothesized that one role for ossicular joint flexibility is to reduce the ossicular input to the cochlea in response to self-generated bone-conducted sounds, but without significantly affecting the normal air-conduction pathway. This hypothesis is tested using a finite-element (FE) model of the human middle ear terminated in a cochlear load impedance. The FE model of the middle ear with accurate representations of the ossicles and ossicular-joint flexibility was developed from micro-CT images. The model was validated using experimental data taken with air-conduction stimulation. Calculations of 3D ossicular motion and intracochlear sound pressure in response to bone-conduction stimulation from 0.1 to 20 kHz were performed with the natural ossicular chain as well as with modifications in which one or both ossicular joints were fused. Comparison between the normal and modified ossicular chains helps to clarify the function of the ossicular-joint flexibility in bone conduction hearing. [Work supported by NIDCD R01 DC05960 and Hearing Health Foundation Emerging Research Grant 2016.]
A non-traditional interpretation of cochlear mechanics of the auditory system
Authors: Biswas Amitava
Published: June 2017

Cochlear mechanics is known to be energized by motility of outer hair cells. This study explored significance of diametric changes of outer hair cells that is usually neglected in cochlear mechanics. Several different mathematical models will be presented to show that diametric changes of outer hair cells can affect deflections of the basilar membrance in a very sensitive pattern under certain naturally possible situations.
Effect of adult aging on pupillary response to auditory stimuli of varying levels of complexity
Authors: Atagi Eriko , Luor Austin , Bushmakin Max , Wingfield Arthur
Published: June 2017

Pupil dilation as a measure of listening effort has been well documented (Kuchinsky et al., 2013), as has the association between adult aging and increased effort in listening tasks (Wingfield et al., 2015). However, age-related differences in the dynamics of pupillary response over time while attending to auditory stimuli have received less study; nor has the nature of the pupillary response to simple stimuli (tones) versus more complex speech stimuli (words, sentences) been systematically explored. In this study we examined multiple parameters of young adult and older adult listeners’ changes in pupil size, including peak amplitude and latency to peak, elicited while making decisions in response to auditory stimuli that varied in acoustic or linguistic complexity. Results showed that the latency to peak pupil size was slower for older adults and for increasingly complex stimuli. The shape of pupillary response curve also changed dramatically with the nature of the stimuli: attending to briefer stimuli (tones, words) resulted in a more peaked pupillary response curve than for sentence-length stimuli, which took a more complex form. These results suggest that both adult aging and stimulus complexity influence the dynamics of the pupillary response as an index of processing effort for acoustic stimuli.
Rippled spectrum discrimination in noise: Manifestation of compression
Authors: Supin Alexander , Milekhina Olga , Nechaev Dmitry
Published: June 2017

In psychophysical experiments, cochlear compression function can be derived by comparison of on- and off-frequency masking, assuming that in the signal representation, the responses to both the signal and on-frequency masker are equally compressed whereas the response to the off-frequency masker is not compressed. In the present study, this approach was used to assess the influence of compression on discrimination of complex signal spectra. The signal was rippled noise, 0.5-oct wide, centered at 2 kHz, 40 to 90 dB SPL. Ripple-density discrimination limit was measured using the ripple-phase reversal test. Simultaneous maskers were 0.5-oct wide noise centered either at the signal frequency (on-frequency) or 0.75 oct below the signal (off-frequency). Masker level increase resulted in decrease of ripple-density discrimination limit. The growth of the on-frequency masker was approximately 1:1. The growth of the off-frequency masking was close to 1:1 at signal levels below 50 dB and 5:1 at signal levels above 60 dB SPL. The results indicate compression of the ripple-pattern signal by approximately 1:5. The observed manifestation of compression implies that the rippled-spectrum discrimination is little susceptible to lateral suppression and off-frequency listening. [Work supported by Russian Science Foundation.]
Loudness perception of pure tones in Parkinson’s disease
Authors: Abur Defne , Lupiani Ashling A. , Hickox Ann E. , Shinn-Cunningham Barbara , Stepp Cara E.
Published: June 2017

Previous work has shown evidence for atypical externally and self-generated speech loudness perception in Parkinson’s disease (PD) with variable methods. This study comprehensively examined loudness ratings of pure tones in individuals with PD and healthy controls, controlling for hearing status. Twenty individuals with PD and twenty-three controls rated the loudness of pure tones on a scale from 1, “Very Soft” to 7, “Uncomfortably Loud.” Tones at 500, 750, 1000, 2000, and 4000 Hz were presented from 35 dB HL to 80 dB HL (or until a rating of 7). A mixed-model analysis of variance (ANOVA) was performed on the ratings to assess the effects of group, frequency, sound pressure level, and ear. Mean loudness growth was determined for each group. There were no significant differences in ratings by frequency. A small but significant difference was seen in mean loudness growth: controls had a shallower slope compared to the PD group. Findings suggest that individuals with PD have a steeper growth of loudness of externally generated tones, in contrast with the findings of previous studies of externally generated and self-generated speech. The underlying causes for impaired perception and production of loudness in PD requires further investigation.
Noise characteristics and their impact on working memory and listening comprehension performance
Authors: DiGiovanni Jeffrey J. , Riffle Travis L. , Nagaraj Naveen K.
Published: June 2017

An emerging body of literature is demonstrating a significant relationship between cognition and listening performance. Noise has been shown to be detrimental to maintaining focus of attention in cognitive tasks. Noise characteristics, for a given SNR, may have differing impacts on these tasks. Fourteen normal-hearing individuals participated in an experiment designed to examine the effects of different background noises on auditory cognitive tasks while still maintaining a high-level of intelligibility (90%). Three tasks were used: a working memory span task, an attention-switching task, and a language comprehension task. The first two tasks were completed in quiet and three different types of modulated background noise, and the language comprehension task was performed in quiet and one modulated noise. Performance in both the working memory span task and attention- switching task were correlated significantly with language comprehension, suggesting that the cognitive resources tapped by these tasks are similar to those required for a complex activity such as comprehending language. Also, all three noise types had a significant effect on performance, which supports the notion that the noises used in the experiment imposed an increase in cognitive load which may impair an individual’s ability to thrive in these situations.
A novel method for quantifying the amplitude of the N1 peak of the human compound action potential
Authors: McClaskey Carolyn M. , Dubno Judy R. , Harris Kelly C.
Published: June 2017

Human auditory nerve (AN) activity is commonly estimated via the compound action potential (CAP), a population response generated by the AN and measured using tympanic-membrane (TM) electrodes. The amplitude of the CAP’s first prominent negative peak (N1) is typically quantified by calculating the voltage difference between the N1 and the maximum voltage of the surrounding positive peaks (“peak-to-peak amplitude”). Despite the widespread use of this method, these peaks have different neural generators, potentially confounding the interpretation of N1 amplitudes. Variability in the amplitudes of these surrounding peaks may also introduce variability to the N1 response, further obscuring findings and reducing reliability. An alternate method is measuring N1 amplitude relative to a time-averaged baseline (“absolute amplitude”), a practice ubiquitous throughout cortical electroencephalography (EEG) studies. The current study recorded CAPs from younger adults with normal hearing to either clicks or tone bursts using TM electrodes placed on the tympanum and measured both peak-to-peak and absolute amplitudes of the N1. For absolute amplitudes, two baseline windows were evaluated, a pre-stimulus window and a whole-trial window. Advantages of measuring absolute N1 amplitudes and implications for assessing AN function will be discussed. [Work supported by NIH/NIDCD.]
Mechanisms of contextual plasticity in sound localization
Authors: Kopco Norbert , Tomoriova Beata , Andrejkova Gabriela
Published: June 2017

Contextual plasticity (CP) is a form of short-term adaptation in sound localization, operating on time scales of tens of seconds to minutes. At least two different mechanisms have been proposed to underlie this effect: 1) adaptation in auditory spatial representation that reflects a change in the stimulus range caused by the context (as the context typically included a distractor presented from a new location outside the range of the experimental targets), and 2) precedence buildup-like mechanism activated by the context (because the context typically consisted of distractor-target click pairs presented on majority of trials and interleaved with target-alone experimental trials). Here a new experiment was performed and previous experimental data were analyzed with the goal of determining which of the two mechanisms is more likely to cause CP. The experiments manipulated the following aspects of the context: 1) whether the distractor and target were presented as pairs 2) the distribution of distractor and target locations, and 3) the order of distractor and target. Results are partially consistent with the adaptation mechanism. But in some conditions, the shifts predicted by the adaptation mechanism were not observed, suggesting that the precedence buildup or other mechanisms are also active. [Work supported by APVV-0452-12.]
Predicting performance across different psychoacoustic tasks
Authors: Wilson E. C. , Perez Zachary D. , Braida Louis D. , Reed Charlotte M.
Published: June 2017

How likely is it that listeners who are superior on one aural attribute are also superior on a second aural attribute? The ability of listeners was measured on two psychoacoustic tasks: (1) detection of tones in noise and (2) detection of amplitude modulation for masked tone complexes. We tested nine listeners (4 M and 5 F) with clinically normal hearing and an age range of 18-21 years using a transformed up-down method with trial-by-trial feedback, and averaged over three measurements. First we determined absolute thresholds for 500-ms tones. Then, using three levels of tones spanning a 30 dB range, we determined both masked tone detection (F = 1, 2, 4, 8 kHz) and masked three-tone discrimination (same center frequencies) with modulation frequencies of Fm = 3, 30, 300 Hz. We discuss how to analyze the data obtained to determine whether a listener’s performance on a given task can be used to predict performance on other tasks.
Finite-element model of the nonlinear distortion and linear reflection sources of the otoacoustic emissions within the mouse cochlea
Authors: Motallebzadeh Hamid , Puria Sunil
Published: June 2017

It has been hypothesized that the otoacoustic emissions (OAEs) are generated at least by two fundamental mechanisms; the nonlinear distortion and linear reflection within the cochlea. The recent studies show that different components of the organ of Corti (OoC) vibrate unsynchronized both in phase and magnitude. The difference is dramatically frequency dependent. We have developed and validated a finite-element model of the mouse cochlea against two sets of measurement at the cochlear base and apex. The nonlinear distortion and linear reflections have been implemented in the model- the former one by the active outer hair cells (OHCs) and the later one by introducing the impedance irregularity in the baseline model components (e.g., stiffness, mass and geometrical parameters). To differentiate the contribution of different components of OoC on the total OAE response, the baseline parameters of the model has been adjusted to vary vibration magnitudes of those components. The preliminary results show that the impedance irregularities generate the phase decay of the stimulus-frequency OAEs more than the nonlinear distortion (e.g., 1-2 cycles per 1kHz with 10% random perturbations of Young’s modulus of the basilar membrane), consistent with data in the literature. The perturbations of other model parameters are under investigation.
A novel dominant GJB2 (DFNA3) mutation in a Chinese family
Authors: Wang Hongyang
Published: June 2017

To decipher the phenotype and genotype of a Chinese family with autosomal dominant non-syndromic hearing loss (ADNSHL) and a novel dominant missense mutation in the GJB2 gene (DFNA3), mutation screening of GJB2 was performed on the propositus from a five-generation ADNSHL family through polymerase chain reaction amplification and Sanger sequencing. The candidate variation and the co-segregation of the phenotype were verified in all ascertained family members. Targeted genes capture and next-generation sequencing (NGS) were performed to explore additional genetic variations. We identified the novel GJB2 mutation c.524C>A (p.P175H), which segregated with high frequency and was involved in progressive sensorineural hearing loss. One subject with an additional c.235delC mutation showed a more severe phenotype than did the other members with single GJB2 dominant variations. Four patients diagnosed with noise-induced hearing loss did not carry this mutation. No other pathogenic variations or modifier genes were identified by NGS. In conclusion, a novel missense mutation in GJB2 (DFNA3), affecting the second extracellular domain of the protein, was identified in a family with ADNSHL.
Inversion of acoustic nonlinearity parameter (beta) from nonlinear resonance ultrasound spectroscopy measurements
Authors: Chakrapani Sunil Kishore , Barnard Daniel J.
Published: June 2017

The acoustic nonlinearity parameter (beta) is well known to be sensitive to lattice parameters and defects. There are several techniques which can measure this parameter such as laser interferometry, capacitance microphone, piezoelectric methods, dynamic acoustoelastic methods, etc. However, the instrumentation required is expensive and complex for some of these techniques. There are also limitations on geometry and surface finish of the samples. Nonlinear resonance ultrasound spectroscopy has been previously used to measure the classic and non-classical nonlinearity of materials. The current work presents a model which can be used to invert the acoustic nonlinearity parameter from nonlinear resonance measurements. A diverse group of solids including metals, and composites were chosen, and nonlinear resonance experiments were conducted to measure the frequency shift. A nonlinear vibration model built from first principles was used to relate the frequency shift to the acoustic nonlinearity parameter. It was also observed that the sign or phase of the parameter can also be measured using this technique. The measured acoustic nonlinearity parameters were found to be in good agreement with reference values obtained from literature.
Psychoacoustic advancement of the tap test for wind turbine blades
Authors: Andreisek Gaetano , Große Christian U. , Seeber Bernhard U.
Published: June 2017

Wind power plants, and in particular their blades, have to withstand significant environmental stresses. Regular testing of the blades’ structural integrity is essential to ensure a lifetime of fifteen to twenty years. Such testing is performed by experienced engineers with a tap test, which is a fast and robust non-destructive technique. By tapping on the shell of the blade and listening to the emitted sound, engineers can assess potential defects in the composite material. This work aims at identifying acoustic features that enable an automated algorithm to perform a tap test. Ten engineers familiar with the inspection of blades participated in a listening experiment in which audible differences between tap test recordings from intact and defective material were rated using a set of defined adjectives. As a result, acoustic features, such as statistical moments of the spectrum, could be correlated with defect-indicating responses. For a more detailed acoustic assessment, further acoustic features were associated with different types of defects and the effect of bearing on the acoustic profile (full blade vs. cut-out) was investigated. Consequently, an informed algorithm incorporating the knowledge of inspectors will be proposed to support the automated determination of defects in blades of wind power plants.
An investigation of detection metrics for the remote acoustic sensing of mechanical changes in a vibrating plate
Authors: Flynn Tyler J. , Dowling David R.
Published: June 2017

Acoustic radiation from a mechanical structure due to broadband forcing is inherently dependent on the structure’s material, geometry, and boundary conditions. Measurements of the radiated field can be used to detect mechanical changes (i.e., defects) when compared to known baseline measurements of the same structure. However, there are many available options for evaluating these changes, and each presents benefits and liabilities. In this presentation, several detection metrics are evaluated for the remote acoustic detection of mechanical changes in a 0.3-m-square by 3-mm-thick aluminum plate with 100 to 2000 Hz broadband forcing. The radiated acoustic field from the vibrating plate is recorded with a 15-element receiver array used to reconstruct an estimate of the plate’s acoustic response. This response is then quantitatively compared to previous baseline responses using cross-correlation, spectral analysis, wavelet analysis, frequency response function analysis, and other relevant detection techniques. The performance of each detection metric is evaluated and ranked by considering the minimum detectible size of a change, required a priori knowledge of the system, and ease of implementation. The feasibility of classification of the detected changes is also considered. [Sponsored by NAVSEA through the NEEC, and by the US DoD through an NDSEG Fellowship.]
Obtaining subjective ratings of voice likability through in-lab listening tests as opposed to mobile-based crowdsourcing
Authors: Fernández Gallardo Laura , Zequeira Jiménez Rafael
Published: June 2017

Micro-task crowdsourcing has emerged as a powerful approach for rapid collection of user input from a large set of participants at low cost. While previous studies have investigated the acceptability of the crowdsourcing paradigm for obtaining reliable perceptual scores of audio or video quality, this work examines the suitability of crowdsourcing to collect voice likability ratings. Voice likability, or voice pleasantness, can be viewed as a speaker social characteristic that can determine the listener's attitudes and decisions towards the speaker and their message. The collection of valid voice likability labels is crucial for a susccessful automatic prediction of likability from speech features. This work presents different auditory tests that collect likability ratings of a common set of 30 voices. These tests are based on direct scaling and on paired-comparisons, and were conducted in the laboratory under controlled conditions—the typical approach—and via crowdsourcing using micro-tasks. Design considerations are proposed for adapting the laboratory listening tests to a mobile-based crowdsourcing platform. The likability scores obtained by the different test approaches are highly correlated. This outcome motivates the use of crowdsourcing for future listening tests, reducing the costs involved in engaging participants and administering the test on-site.
Influence of environmental background noise on speech quality assessments task in crowdsourcing microtask platform
Authors: Naderi Babak , Möller Sebastian , Neubert Frank , Höller Victor , Köster Friedemann , Fernández Gallardo Laura
Published: June 2017

It is important to realize in which environments a speech quality evaluation test can be carried out to achieve reliable results outside the laboratory. We report on our current activity on using microphone signals for evaluating environmental conditions in crowdtesting. In order to analyze the impact of environmental noise, a two-phase experiment is conducted using a mobile crowdsourcing platform. A speech quality assessment task is used with stimuli from the SwissQual 501 database from the ITU-T Rec. P.863 competition (kindly provided by SwissQual AG). The first phase of the experiment is conducted in a laboratory, in which participants are assigned to either silent or background noise simulation (with Cafeteria and Road Noise) study groups. In each case 5 seconds of environmental sound are recorded by the participants before and after performing the task. Next, the same participants were asked to perform the same task in a real living room, cafeteria, or any other environment (and proofing it by taking photos) and again to record the environmental noise. Environments are labelled based on their influence on the result of speech quality assessments. Later, different features like loudness, noisiness, etc. will be extracted from the recorded audio files and used to predict if the environment is suitable for performing a crowdtesting speech quality assessment.
Speakers adapt speech based on percieved miscommunication
Authors: Buz Esteban
Published: June 2017

Recent work suggests that speakers can exaggerate their speech based on perceived communicative success (Buz et al., 2016). However, the flexibility and sophistication of this speech adaptation is relatively under-explored. We thus investigate whether this adaptation can be responsive to context-specific demands (e.g., exaggerating speech in contexts with increased potential for miscommunication), whether adaptation can target specific phonetic/acoustic properties (e.g., specifically exaggerating aspects of speech that may reduce miscommunication), and whether this adaptation involves inference about the potential causes of miscommunication. We investigate these questions in a web-based spoken communication game where we manipulate speakers' perceived communicative success. We find that speakers “smartly” adapt to miscommunication so as to increase speakers' likelihood of subsequent communicative success. The results argue for a speech production system that incorporates past experience and can adapt fine-grained properties of speech to better achieve communicative goals.
Synthesis of non-uniformly spaced linear antenna arrays using a data-driven probabilistic model
Authors: Misiunas Nicholas , Chandra Kavitha , Thompson Charles
Published: June 2017

The problem of beam-forming from non-uniformly spaced antenna elements on linear and planar arrays is investigated. The objective is to design a probabilistic model for identifying the locations of a minimal set of elements that collaboratively generate a beam that matches specified beam width and side lobe level. A data-driven approach is undertaken with several thousand viable element positions obtained computationally using the firefly metaheuristic optimization algorithm, where each firefly models an antenna array of fixed number of elements. Analysis of inter-element spacings of the viable positions shows that whereas all spacings exhibit some degree of dependence with neighboring spacings, the region at the end of the array exhibits a higher correlation radius. Accurate modeling of this section is important for minimizing variability in generated random beam forms. A sequential regression model is proposed to predict successive inter-element spacings beginning with the boundary of the aperture. Application of the aggregate of previously predicted spacings as the predictor allows one to transform the non-linear structure to a linear predictive model. Arrays synthesized by this model yield a good performance, with nearly 90% of generated array beam patterns satisfying required beam width and side lobe level.
Wavefield separation projector processing with a prioriknowledge for acoustic source localization in rooms
Authors: de Rosny Julien , Nowakowski Thibault , Daudet Laurent
Published: June 2017

In bounded media, wavefield separation projector is an array processing used to extract the direct path from the reverberated ones. Associated with a simple sparse localization algorithm, it makes an attractive method for source localization in rooms of unknown shape. However, the large number of microphones required by the method can prevent its applicability. In this work, we propose to add three different a priori knowledge to dramatically decrease the number of microphones. First, an estimation of the critical distance allows to reduce the required rank of the projection operator and therefore the number of receivers. The second method increases the number of receivers thanks to “virtual measurements” on the boundaries, when the room geometry is partially known. Finally, the last method requires a simple calibration step based on the passive recovering of the Green’s functions between all the pairs of microphones, which also extends the model to weakly inhomogeneous propagation medium. The properties of the 3 methods are discussed. We show numerically and experimentally that these methods lead to a precise source localization, with a moderate number of microphones.
Estimation of speech source direction for hearing aid application using smartphone
Authors: Panahi Issa M. , Kehtarnavaz Nasser , Thibodeau Linda
Published: June 2017

In our hearing aid research project funded by NIH-NIDCD we utilize smartphone and its features as a powerful platform to implement complex signal processing algorithms which would improve hearing aid applications. Among the required algorithms, is finding the direction of arrival of speech source signals which can improve the performance of hearing aid devices for the users. In this poster presentation, a signal processing algorithm for estimating the speech source direction and its real-time implementation on an Android smartphone are demonstrated. The visual display of source direction on the smartphone panel can be used to align the phone and its two microphones in the right direction of source to enhance the signal to noise ratio and improve the reception of speech signal. A demo unit will be presented showing the real-time operation of the proposed method on an Android smartphone.
Coherence-based phase unwrapping for broadband signals
Authors: Cook Mylan R. , Gee Kent L. , Sommerfeldt Scott D. , Neilsen Tracianne B.
Published: June 2017

In this paper, a coherence-based method for unwrapping the relative phase between microphones are investigated. For broadband signals, this method has the potential to lead to more accurate intensity vector estimations using the Phase Amplitude and Gradient Estimator (PAGE) method [D. C. Thomas et al., J. Acoust. Soc. Am. 137, 3366-3376 (2015)] Simple unwrapping methods function by detecting phase jumps above a threshold, which works well for frequencies associated with high signal coherence. However, since unwrapping for these methods is triggered by only one previous frequency data point, frequency regimes of low coherence are often unwrapped incorrectly. By including coherence in a phase unwrapping algorithm, these errors can be reduced. Regions of relatively low coherence are given less weight in phase unwrapping, and are checked for unwrapping errors. For broadband signals with continuous relative phase, using both the coherence and multiple data points to unwrap, frequencies associated with low coherence result in fewer unwrapping errors. Phase values for jet noise data with low coherence (<0.1) have been successfully unwrapped using this method, and have resulted in more reliable PAGE intensity estimates. This paper also investigates unwrapping in interference nulls produced by coherent, radiating sources. [Funded by the NSF.]
Acoustic transfer characteristics study through the fingers vibrations using wrist vibrator
Authors: Park Hyung Woo , bae myungjin
Published: June 2017

In these days, people are exposed in many kind of noise, such as machinery, aircraft, construction site, or road traffic. The noise is situated in one part of the modern life of human. In this study, we confirmed that the characteristics of acoustic transmission through the finger in noisy environment. To investigate the function of the sound transfer to ear, we measure the vibration from the wrist actuator fingertips to figure out the mechanisms of transmission. And we using the bone-conduction equivalent circuit for compensation with normal hearing and estimate the acoustic characteristics. The experiment of propose mechanism, set the noise environment with monitor speakers in semi-anechoic room and check the acoustic transfer performance.
Parameter optimization for acoustic fault samples kernel confidence measure
Authors: Wei Na , zhang linke
Published: June 2017

Sample expansion is an effective way to solve the incomplete samples problem in acoustic fault source identification, and high confidence expanded samples contribute to the classifier performance. Before a kernel-based confidence measure (KBCM) was introduced for acoustic expanded samples confidence measure. Kernel parameter is a key point to maintain the KBCM algorithm performance. A novel parameter optimization criterion for Gaussian function with consideration of sample confidence is proposed. First, the expanded samples of confidence more than 0.5 are selected and further combined with the real samples into a new training samples set. Then based on this new set, an optimization objective function of maximizing between-class separability and minimizing within-class separability is put forward. Experiments on two-dimensional normal distribution data and multi-dimensional noise source data verify the efficiency of the proposed method.
Spatial focusing of a one-channel time-reversal acoustic mirror in an underground water storage tank at audible frequencies
Authors: Maffei Gaston , Scoccola Gabriel , Wisniacki Diego A. , Spiousas Ignacio , Alberti Alejo , Eguia Manuel C.
Published: June 2017

We performed a one-channel time-reversal acoustic mirror for a wide-band (30 Hz to 20 kHz) impulse in a 30 × 5 meters (diameter X height) empty cylindrical tank made of concrete, with columns and beams. The time-reversed pulse (or equivalently, the autocorrelation of the impulse response) peaks 30 dB above the temporal sidelobes. We measured the two-dimensional spatio-temporal focusing pattern of the time-reversal process with a 7.5 cm grid resolution and observed a circular converging/diverging wave. The wide-band time-reversed pulse peak decays at the level of the sidelobes around 70 cm away from the focusing point. We also analyzed this focal spot width as a function of frequency and compared the results with a numerical simulation of the cavity using a finite element method.
A weak target detecting method based on multistatic information fusion
Authors: Chen Yang , Sheng Xueli , Cang Siyuan , Lu Dian , Guo Longxiang , Yin Jingwei
Published: June 2017

The detecting performance of active sonar have been affected by the weak targets scattering and serious noise background. If artificial reducing the threshold to get high detecting capability, the false alarm probability will be very high. Therefore, this paper propose a weak target detecting method based on multistatic information fusion. After getting more information about the target from different positions and extracting the target feature vectors to make a fusion, a better recogniting performance will be present. The target scattering centers are extracted by CLEAN technique, which could avoid extracting the false scattering centers, and adapt in low signal to noise ratio (SNR). The neural network classifier is used to make a fusion and recognize the target. Simulation results show that this method has better target identification performance and low false alarm probability, demonstrating the target features fusion has high value for active sonar detecting in the future.
Target tracking technology for reducing false alarm
Authors: Wang Xiaoyu , Sheng Xueli , Yu Hanjun , Guo Longxiang , Yin Jingwei
Published: June 2017

Because of the complex marine environment, there are a large number of false arms when the active sonar is detecting targets. It is difficult to find the real targets, so the false negative rate has a significant increase. In order to suppress the clutter better and reduce the false alarm rate maximally, the problem of target detection via Multiple Hypothesis Tracking based Track Before Detect (MHT -TBD) is considered in this paper. MHT -TBD is a data association method that could remove wild spots in a clutter environment and save useful data. But for high maneuvering targets, the tracking success rate of MHT-TBD is significantly reduced. An improved MHT-TBD method named interactive multimode MHT-TBD (IMM-MHT-TBD), which combines interactive multimode with multi hypothesis tracking is introduced in this paper. It shows a superior performance in high maneuvering targets tracking by maintenance and data association in a clutter environment. Simulation results show that IMM-MHT-TBD can solve the problem of tracking high maneuvering targets effectively.
Excitation of leaky lamb waves in cranial bone using a phased array transducer in a concave therapeutic configuration
Authors: Adams Chris , McLaughlan James R. , Nie Luzhen , Cowell David , Carpenter Thomas , Freear Steven
Published: June 2017

Ultrasonic therapeutic transducers that consist of large numbers of unfocused, low power elements have begun to replace single, focused, high power elements. This allows the operator to use phased array techniques to change the focal position in the tissue during therapy. In transcranial therapy, this phased array configuration is essential to reduce local heating at the highly attenuating bone. Recently, Dual Mode Ultrasound Arrays (DMUAs) have been developed which leverage existing elements for imaging during therapy. DMUAs have the benefit of both the therapeutic and imaging systems being co-registered. This improves upon the existing approach of using a separate ultrasound system for guidance, as the acoustic beam path is the same for both. Unfortunately, the highly reflective nature of bone means that DMUAs have not been applied to transcranial therapy. However the recent near-field observation of lamb waves in cranial bone opens the possibility for DMUAs to be applied to a guided wave scan of the skull. This would allow co-registration of the bone’s ultrasonic properties with the therapeutic axis which would facilitate adaptive beamforming. In this work, a beamforming scheme for the excitation of guided waves in cranial bone using a therapeutic phased array is described and demonstrated experimentally.