bluuebunny/crossref_metadata_2025 huggingface dataset:
Processing seismic source transients to quantify ecosystem impact
Authors: Sidorovskaia Natalia , Li Kun
Published: November 2019

Modeling of acoustic field metrics for transient seismic signals in ocean environments is required for the regulatory and resource management purposes. The validation by calibrated measurements is a critical step to assess model’s accuracy. The talk discusses acoustic metrics derived from the field data collected in the Northern Gulf of Mexico. The purpose of the experiment was to characterize 3-dimemsional field of the industrial seismic exploration array. Received Sound Pressure Levels of direct arrivals showed a large variability (up to 50 dB re 1 μPa) for a fixed distance between source and receiver indicating that the distance cannot be used as a single parameter to derive meaningful exposure thresholds. However, the far-field primary acoustic field variations with distance along the true acoustic path for a narrow angular bin are accurately predicted using a simplified model of the theoretical monopole source in free space. The source level of a monopole depends on radiation direction. The different acoustic metrics show robust relationships. As distance between source and receiver increases, the direct arrival may not be present (shadow zone). In this case more comprehensive propagation modeling is required. [Research funded by the Sound and Marine Life Joint Industry Programme.]
A program-dependent digital compressor for auditory prostheses specialized for signal transients
Authors: Tarr Eric W.
Published: November 2019

Dynamic range compressors found in hearing aids and cochlear implants are designed to have a programmable response time. In particular, the attack and release parameters control the rate at which a compressor responds to the onset and offset of a signal transient. Some previous perceptual studies have found preferences for faster response times, while other studies have found preferences for slower response times. An explanation for the conflicting results is that the experiments’ stimuli and perceptual measures have varied. These results are indicative of the challenge in designing compressors for a wide range of speech, environmental, and musical signals each with unique transient characteristics. Researchers have proposed using multiple wide-band compressors or parallel narrow-band compressors with different response times. This research presents an alternative approach for a single compressor having adaptive, program-dependent, attack and release times. Specifically, the response times depend on the rate of change of the compressor’s gain reduction. When a transient causes a large change in gain reduction, the response times are faster. During periods with small changes in gain reduction, the response times are slower. Considerations for real-time implementation are discussed.
Characterization of sound waves propagating in a fluctuating ocean: experimental validation with ALMA
Authors: Real Gaultier , Fattaccioli Dominique
Published: November 2019

The authors present an acoustic system, designed by DGA Naval Systems, dedicated to the study of sound propagation in challenging environments. The system is called ALMA for Acoustic Laboratory for Marine Applications. Shallow and coastal waters, where oceanographic phenomena (such as linear internal waves, tides and 3-D effects) interact with acoustic propagation, represent the main area of deployments. Since 2014, 5 at-sea campaign have been successfully conducted in the Mediterranean Sea and in the Atlantic Ocean. They mainly consisted in propagating sound waves in the 1–15 kHz frequency band using fixed or towed sources towards a modular passive acoustic array. The latter is composed of 8 rigid arms carrying 16 hydrophones each. These arms can be, and actually were, arranged in various shapes, depending on the goal of the experiment. Environmental sensing using thermistor strings and CTD cast complete the experimental equipment. The analysis of the 2016 campaign demonstrates the ability of the system to gather data representative what was described as the “saturation” theory by S. Flatté in the 1980s. In fact, criteria based on the mutual coherence function and the normalized acoustic intensity probability density function allow to explain the observed variability of detection performance on a 4x32-hydrophones vertical comblike passive acoustic array. A global progress report on the use of data gathered by the ALMA system, as well as future plans—including deployment in high latitudes environments—will be discussed.
3-D acoustic propagation through an estuarine salt wedge
Authors: Reeder D. Benjamin , Lin Ying-Tsong
Published: November 2019

The estuarine salt wedge presents a dynamic and highly refractive waveguide, the acoustic propagation characteristics of which are controlled by the water column sound speed gradient and boundary interactions. Acoustically, the salt wedge consists of two isospeed layers separated by a thin, three-dimensional, high-gradient layer. The behavior of a broadband (500–2000 Hz) acoustic field under the influence of an estuarine salt wedge in the Columbia River estuary is explored using two 3-D acoustic propagation models: 3-D rays and 3-D parabolic equation (3DPE). These model results are compared to data collected during a field experiment in 2013. Results demonstrate that the dominant physical mechanism controlling acoustic propagation in this waveguide shifts from 3-D bottom scatter in a non-refractive waveguide (before the entrance of the salt wedge) to 3-D acoustic refraction with minimal bottom interaction in a refractive waveguide (when the salt wedge occupies the acoustic transect). Vertical and horizontal refraction in the water column and out-of-plane scattering by the bottom are clearly evident at specific narrowband frequencies; however, these mechanisms contribute to, but do not account for the total observed transmission loss.
Seismo-acoustic wave propagation in the Rade of Hyères (France) generated by counter-mining of explosive devices: comparison between numerical simulations and real experiments
Authors: Wang Fang , Favretto-Cristini Nathalie , Cristini Paul , Garlan Thierry , Demoulin Xavier , Morio Olivier , Deschamps Anne , Ambrois David , Beucler Eric
Published: November 2019

In order to study the impact of the potential explosion of WWII unexploded ordnances which are commonly found along the French Mediterranean coast, a series of underwater explosions were conducted in December 2018 in the Rade of Hyeres in France. These explosions were realized within the framework of the POSA project, led by SHOM, and which includes LMA, Géoazur and LPG Nantes which addresses the upstream hazard management issue of such counter-mining operations in the marine field. From topographical and sedimentary measurements performed in this area, physical and geometrical characteristics of the marine seabed have been carefully selected to serve as input data for numerical simulations of seismo-acoustic wave propagation from the source to several seismometers deployed on the coast of Hyeres and surrounding islands. Numerical simulations were conducted using a spectral-element method in the time domain. The impact of the explosive device (source) charge and its location (on the seabed or in the water column), together with the impact of the marine environment properties, on the simulated signals have been studied. The source time function is estimated from in situ acoustic signals recorded by hydrophones located around the detonation location. The seismic data recorded on the coast are used to calibrate the numerical simulation and to evaluate the impact of different marine environments with special attention to the influence of the characteristics of the sediment layer.
Theoretical analysis of bottom reflected broadband waveforms
Authors: Thorsos Eric I. , Jackson Darrell , Tang Dajun , Hefner Brian T. , Porter Michael B. , Henderson Laurel
Published: November 2019

Bottom reflection of broadband waveforms from explosive sources leads to pulse distortion, including the presence of a precursor to the main pulse, a topic that goes back to the 1950s [Arons and Yennie, JASA 22, 231–237 (1950)). A theoretical analysis of broadband bottom reflection can provide valuable insights into observed waveform distortion and its dependence on the grazing angle and sediment properties. When the attenuation in the bottom can be approximated as varying linearly with frequency, the magnitude of the reflection coefficient is independent of frequency, but with a common phase shift over positive frequencies (and with the opposite phase shift over negative frequencies). Combining these contributions leads to the pulse distortion . Variations of the sediment properties that cause the same phase shift at a given grazing angle produce the same pulse distortion. Conversely, inferring a phase shift from the pulse distortion can be used to place constraints on the inversion of sediment properties. Examples will be discussed. [Work supported by ONR.]
Modelling sound propagation in the ocean from multiple sound sources
Authors: Kirby Ray
Published: November 2019

Modelling sound propagation in ocean waveguides normally assumes that a sound source can be represented by a single, idealised, point source. However, the ocean environment contains many different and complex sound sources and it may not always be appropriate to represent these as a point source, especially in the acoustic near field and/or shallow water environments. Accordingly, sound propagation in an ocean waveguide is examined here using a numerical model to accommodate multiple point and dipole sources that are arranged vertically in the ocean. Predictions are obtained using a semi analytic finite element approach, which is a normal mode model that computes eigenmodes propagating in the range direction. This enables the addition of multiple point sources, as well as depth dependent fluid properties, and compressional and shear waves in the seabed. An investigation is then undertaken to ascertain where the acoustic near field ends for complex sources in order to examine the appropriateness of the assumption of an idealised point source for these more complex problems.
Variational formulation for sensitivity analysis of a two-dimensional energy flux model
Authors: Langhirt Mark , Holland Charles W. , Martinelli Sheri
Published: November 2019

Energy flux propagation models have demonstrated promising results in efficiently approximating both incoherent and coherent field intensities in range dependent environments [Holland, J. Acoust. Soc. Am. 128, 2596 (2010); Harrison J. Acoust. Soc. Am. 133, 3777 (2013)]. The efficiency of energy flux models is advantageous when applied to solving complex problems in environments that would typically require much more computational effort with other propagation models. Some environmental range dependencies that have been investigated with the energy flux model include sound velocity, bathymetry, and sediment properties. Though comparisons have been made of static solutions between energy flux and other propagation models, there has been limited investigation of energy flux models in regards to variational sensitivity to perturbations in the environment. The applications for variational analyses are broad in a general sense, but the core goal is to capture the robustness of the forward model to perturbative inputs. This study seeks to establish the ground work for defining an adjoint-model-based sensitivity analysis of a 2-D range-dependent energy flux model.
High fidelity modeling of pile driving acoustic energy
Authors: Heaney Kevin D. , Seger Kerri , Halvorsen Michele B. , Ainslie Michael A. , Nijhof Marten , Muller Roel
Published: November 2019

Pile driving for the installation of wind farms has become a recent topic of interest as we seek to learn how to protect the marine environment while energy efficient offshore turbines are installed. For environmental compliance, propagation models for spreading from a point source are sometimes used to evaluate impact volumes. Use of a point source is problematic in that a pile (either hammered or shaken using a vibratory source) fully extends through the water column and cannot be considered a point source. In this paper we present a hybrid model solution to evaluate the sound field at close and far ranges. First, a finite element model, consisting of the hammer, pile, the nearby seawater and the sediment, is used to computed the acoustic pressure field at a short range (∼3 m). The sound pressure field versus depth and frequency at this range is used as the starter field for the Parabolic Equation and the field is then propagated to range, including range dependent environments. Impact volumes, for various marine species hearing groups are computed. [Work supported by BOEM.]
Study on the characteristics of the water-entry sound of low-speed metal sphere
Authors: Yang Yihan , Li Qi , Shang Dajing , Tang Rui
Published: November 2019

In this paper, the underwater acoustic characteristics of low-speed metal spheres are measured by direct measurement from the angle of sound pressure of Initial impact sound and bubble pulsating sound, which mainly includes the research on the impact of ball size and ball entry velocity on water entry sound and the characteristics of bubble radius. Experimental data were obtained through a large number of experiments, and the data were simply processed and then fitted by MATLAB. The accuracy of experimental measurement results is analyzed from the perspective of statistics. The results show that the relationship between sound pressure and particle size, 2/3 power of water-entry velocity are exponential function with a base of 10; the relationship between sound pressure level and particle size, 2/3 power of water-entry velocity are linear function; the relationship between bubble radius and particle size, 2/3 power of water-entry velocity are linear function. The variation of each physical quantities with particle size and water entry velocity obtained in this study can be used for simple prediction. With the further research of the subject, the research results will be further optimized.
Case study of the renovation of Sacramento City Community College auditorium, two theaters and twenty-nine classrooms
Authors: Pettyjohn Steve
Published: November 2019

A renovation was undertaken of the main auditorium, a small theater, a black box theater and twenty-nine classrooms to bring them into the digital age. These facilities had been designed in the late 1960s with only minor changes to update, for example, the black box theater. The project involved the architectural and mechanical acoustical design of these spaces and the design of the audio-video system for the performance areas and for the classrooms. The focus of this paper is on the renovation of the auditorium. A major change was removing the balcony seating, reducing the seating from 1100 to 600. The space was to be used for programs ranging from plays to rock music to symphonies. This meant that the reverberation time had be variable from less than 1-s to over 2-s. Panels were designed to swing on the side walls into two positions to achieve the variable reverberation times. The sound system for the auditorium, specifically the mixing board, had to be designed around that used for classroom instruction. Financial problems created large problems as did a decision to remove the specifications for vibration isolation of the HVAC system. A summary of results will be presented.
A case study of a 600-Seat Community College Theater renovation
Authors: Keefe Joseph A.
Published: November 2019

The Theater at Monroe Community College in Rochester, NY, was a space with low reverberation time, undesirable focused sound reflections, excessive HVAC system noise, and a haphazard collection of sound system equipment. Design of a renovation commenced in 2015, with strong focus on acoustical improvements. Visually stunning wood “ribs” create aimed reflecting surfaces, promote diffusion, and increase room volume. The ribs converted a previously unbroken ceiling layer to a layer transparent to sound transmission; a gypsum board “lid” was specified to attenuate rainfall noise while maintaining as much room volume as practical. Traditional application of sound absorption to avoid echoes was not desirable in this space; acoustically transparent railings and out-of-plumb rear walls were designed to meet architectural needs while affecting reverberation time minimally. New HVAC ductwork was specified throughout the space, but existing ductwork remained in the mechanical room and in the basement below the theater. The renovation was completed in 2017. The mid-frequency reverberation time increased from 0.7 to 1.1 seconds, while the HVAC system sound level was reduced from a maximum of NC-40 to NC-30. A new sound system was designed and specified that results in uniform high-quality coverage for all seating areas, including the control balcony.
Metropolitan metamorphosis: A tale of two theater’s journeys to acoustical acceptance
Authors: Tanen Robert M. , Hulteen Scott
Published: November 2019

Not every assembly space (be it a lecture hall, theater, multi-purpose room, GymaNataCafaConfraTorium, etc.) has the prestige or budget of Concertgebouw in Amsterdam, or the Kimmel Center, here in Philadelphia. Many of the day-to-day jobs that are encountered in the consulting field are renovations of existing spaces at local educational facilities or businesses, and they require the same love and attention but have different restrictions and challenges. Some roadblocks and hurdles include tight budgets, accelerated schedules, space constraints, and/or complex (sometimes fragile) bureaucratic procedures. Today we will look at two recent renovations: one a transformation of a space-restricted, dark and sterile school performance space into a modern, clean and functioning multi-purpose theater; the other a poorly laid out, non-functioning, outdated auditorium (better suited for a fall-out shelter) into a warm, comfortable, accommodating and inspiring space. These two case-studies outline the challenges encountered, solutions developed and heartwarming transformation details that made the renovations a success.
Willson Auditorium renovation
Authors: Connolly Sean
Published: November 2019

As a small-city community theater, the 1100 seat Willson Auditorium is a multi-use facility in every sense of the word. This former high school auditorium, where Gary Cooper performed as a student, is now home to performances by the local symphony, an opera company, ballet companies, traveling amplified acts, and high-school and middle-school music and drama students. This case study discusses how the distribution of sound-absorptive material and the shapes of surfaces used in the auditorium provided less than ideal acoustical characteristics and weak projection of sound from the stage for many of the users. The measures taken to correct those issues as part of a renovation will also be discussed, including an increase in volume and redistribution of sound-absorbing and sound-reflecting surfaces, that prompted the school district music director to say the teachers “are going to freak out when they hear the way it sounds.”
Biological-physical coupling in a highly advective ecosystem: Through a lens of diel vertical migration
Authors: Sato Mei , Benoit-Bird Kelly J.
Published: November 2019

A mismatch in sampling resolution between biology and physics has been one of the fundamental challenges in advancing our understanding of ecological processes in the ocean. The recent deployment of cabled observatories enables the collection of active acoustic data with coverage and resolution comparable to physical data, providing an unprecedented ability to observe the behavior of zooplankton that are critical trophic link in the food web. Using multifrequency acoustics, acoustic Doppler current profiler (ADCP), and meteorological sensors deployed by the Ocean Observatories Initiatives (OOI) in the Northern California Current System, we explored small-scale upwelling impacts on diel vertical migration exploiting the frequency and predictability of this ubiquitous behavior. We found that the vertical extent of diel vertical migration changed relative to upwelling intensity. Migration behavior was completely suppressed during strong downwelling periods. Zooplankton migrated throughout the water column during relaxation periods while decreasing their migration distance as the winds shifted to upwelling favorable conditions, potentially increasing their accessibility to food resources. These results suggest that animals adapt their behavior to accommodate changes in the physical environment.
Quantitative examination of data processing effects on species classification from broadband echosounders
Authors: Benoit-Bird Kelly J. , Waluk Chad M.
Published: November 2019

Measurements from broadband echosounders hold much promise for improving the ability to discriminate biological targets in the ocean. However, it remains unclear how effectively the increased bandwidth can be leveraged in situ and few clear protocols exist to guide the user in making choices in processing these voluminous data. We used a 45–170 kHz wideband echosounder and a high definition video system to simultaneously observe aggregations of fish and invertebrates in situ using a remotely operated vehicle (ROV). The dataset contains a large number of echoes collected in a minimally disturbed context, avoiding any effects of compression/decompression of air-containing target and the identity of the targets was verified at a scale and resolution comparable to the acoustic measurements. Using these data, we quantitatively explore the effects of (1) the chosen frequency resolution, (2) the method and scale of data averaging, (3) available bandwidth, (4) data normalization choices, and the (5) use of volume scattering versus resolved single targets on the ability to discriminate echoes from three species. There was sufficient information in broadband data to accurately discriminate between echoes from known species but the accuracy of classification was strongly affected by the data processing choices.
Suppression of in vivo flow artifacts in power Doppler through spatial and angular coherence beamforming
Authors: Dahl Jeremy J. , Yoon Byung Chul , Durot Isabelle , Ducey-Wysling Jessica , D’Hondt Aurélie , Patel Bhavik , Rubesova Erika , Jakovljevic Marko , Li You
Published: November 2019

Power Doppler imaging is traditionally the flow imaging technique utilized clinically in the task of flow detection. Due to the relatively low pulse repetition frequencies used, power Doppler ensemble sizes are small to allow real-time imaging. The small ensemble size, however, makes power Doppler imaging subject to the so-called flash artifact due to limited stationary clutter filtering capabilities. In addition, with the increasing population of overweight and obese individuals, power Doppler imaging is subject to higher amounts of thermal noise and reverberation artifact that pass through the stationary clutter filters. We present coherence beamforming techniques, applied to in vivo human imaging, to demonstrate their ability to reduce flow artifacts and noise in power Doppler imaging. Using coherence beamforming techniques in Coherent Flow Power Doppler (CFPD), we show that artifacts due to reverberation and thermal noise are reduced, corresponding to an increase of 7.5 dB in signal-to-noise ratio, in liver imaging of overweight and obese individuals. Similarly, we demonstrate coherence beamforming techniques in CFPD to reduce flash artifacts in videos of the neonatal brain.
Plane-wave imaging of ocular blood-flow
Authors: Silverman Ronald H. , Urs Raksha , Ketterling Jeffrey A. , Yiu Billy Y. , Yu Alfred C.
Published: November 2019

Blood-flow plays an important role in pathogenesis and progression of many ocular diseases. While optical coherence tomography angiography (OCT-A) has revolutionized depiction of the retinal vasculature, it provides little information regarding flow velocities and cannot visualize the arteries and veins supplying and draining the eye. We implemented plane-wave ultrasound methods to address these shortcomings using the Verasonics Vantage-128 with L22-14 linear array probes. We are performing clinical studies of glaucoma, retinopathy of prematurity, preeclampsia, vascular malformations and tumors. Scans are typically acquired for 3 s, capturing 2-3 cardiac cycles. Compounded data (2–6 angles) acquired at a 1–6 kHz PRF are post-processed using a singular value decomposition filter to suppress stationary structures and power-Doppler images are generated. By selecting areas-of-interest representing specific vessels or the choroid (the vascular tissue underlying and supplying the retina), spectrograms are produced, enabling measurement of flow velocities and resistive indices for each vascular component. We are also performing pre-clinical studies of blood-flow in the rat eye, with and without introduction of contrast microbubbles, and are developing super-resolution methods that approach OCT in resolution for improved depiction of the microvasculature as we develop the rat as a model of glaucoma.
Detecting kidney stones using twinkling artifacts: Survey of kidney stones with varying composition and size
Authors: Wood Benjamin , Urban Matthew W.
Published: November 2019

In recent years, work has been done to understand the mechanisms of Doppler ultrasound twinkling artifacts (TAs) and why they appear over kidney stones. In this work, twinkling artifacts were evaluated as a possible method of locating and characterizing kidney stones. Doppler ultrasound scanning was used to evaluate 47 stones of different types and sizes. An isolated stone study was used to understand the behavior of the TAs while varying transmit voltages. An ex vivo kidney study was conducted to determine if TAs were localized to the stones. An ex vivo randomized stone placement study was used to evaluate the robustness of detecting and locating stones. The TAs were also shown to be isolated to the stone when placed in an ex vivo kidney. The randomized stone placement study showed that this method could find all 47 used stones with only two false positives. A few limitations to this method were found with issues accurately sizing stones as well as difficulties in specificity for characterizing the stones. Further work will be done on these limitations by improving the Doppler acquisition and processing code as well as evaluating the use of TAs in human studies.
Orthocomplement reduced order models for strongly coupled structural-acoustic systems
Authors: Cipolla Jeffrey
Published: November 2019

Despite the enormous strides in computing power, reduced-order models (ROMs) remain essential for design optimization and early stage design. The energetically optimal basis for ROMs of vibroacoustic systems derives from the coupled Eigen problem: no basis of smaller dimension contains a greater amount of system energy. While vital, this L2-type framework is also insufficiently accurate on a pointwise basis for many problems. A simply supported beam with a point load is an obvious thought experiment: the smooth modal functions converge to the correct displaced shape very slowly. The well-known “residual mode” or orthocomplement concept overcomes this problem, by augmenting the space of modal functions with static solutions to the point loads. These new residual modes are orthogonalized against the modal space, and used otherwise conventionally. This work describes the development of ROMs of submerged structures by extending the residual mode approach to the strongly coupled structural-acoustic case. We derive methods to use these ROMs in substructures. Numerical examples show that the structural acoustic residual mode formulation is very effective in improving the solution method in the low-frequency limit, especially in the fluid, and also at the high-frequency limit, where response quantities tend to the average of the direct-solve FEM response.
Classical modal analysis and asymptotic modal analysis of structural and acoustic systems
Authors: Sung Shung H. , Nefske Donald J.
Published: November 2019

The Classical Modal Analysis (CMA) method is commonly used to solve for the vibroacoustic response of large scale structural and acoustic systems. In this method, the modal equations of motion are developed and solved for the modal coefficients to form a modal series solution to predict the structural and acoustic responses. The CMA method generally works well in the low-to-medium frequency range. However, at high frequencies, the large number of modes required in the summation limits the usefulness of the CMA method and alternative methods, such as Statistical Energy Analysis (SEA) and Energy Finite Element Analysis (EFEA) have been developed. As an alternative to SEA and EFEA, the Asymptotic Modal Analysis (AMA) method has been developed in which the modal series summation in the CMA method is asymptotically approximated based on the overall frequency and band averaging of the modal series. The AMA method thereby predicts the band averaged frequency response in the high frequency range and also has the advantage of providing the spatial distribution of the response based on the summed modes in the frequency band. In this paper, an example of coupled cavity-plate system subject to external random white noise pressure load excitation is developed to illustrate the CMA and AMA methods and to address their accuracy.
Evaluating project-related noise impacts on sleep in environmental assessments: A proposal to apply decibel adjustments to nighttime noise events based on their time of occurrence over the sleep period time
Authors: Michaud David , Keith Stephen , Denning Allison
Published: November 2019

Health Canada is updating its Guidance for evaluating noise in environmental assessments. Current advice on sleep is drawn from the World Health Organization (WHO) which advises that average noise within the bedroom not exceed 30 dBA, and noise events not exceed 45 dB LAmax on more than 10–15 occasions. Both limits increase by 15 dB outdoors assuming partially opened windows. The WHO’s recommended outdoor nighttime annual average of 40 dBA is also used. Two situations commonly arise: (1) the outdoor annual average sound level is exceeded at baseline; or (2) the number of events during sleep exceeds 15, but are just below threshold. Under these situations, the estimated prevalence of high noise annoyance is applied to protect sleep because it includes a 10 dB nighttime penalty. However, this may not account for the variation in the acoustic threshold that has been observed throughout the sleep period. This paper presents two proposals: (1) apply a decibel adjustment to noise events occurring during periods where thresholds are known to be lower (i.e., the first hour and final 3 h) and/or (2) derive a rating level for estimating annoyance using an alternative nighttime adjustment that splits the night into distinct time periods.
A study on compatibility of rhythm sound with existing sound in Clackson
Authors: Lee WonHee , Bae Myungjin
Published: November 2019

The sound of a car 's clackson was developed and used 100 years ago, but can cause traffic noise to pedestrians and drivers, which can be harmful. We have previously proposed a new familiar Clackson sound with a different rhythm or tempo using the existing Clackson. However, since the existing Clackson sound is needed in emergency or special cases, this study newly proposed a compatible Clackson sound method. First of all, pressing the center part of the handle of the driver's seat while driving starts a rhythmic clack sound, on the other hand, after a short touch, you can press and hold down to use the existing Crackson sound. We usually use a human-friendly Klaxon sound that is designed considering 100 people's hearing fatigue, brain wave test, stress index, etc., and when using the existing Klaxon sound in the case of emergency. Therefore, the proposed Clackson sound can be used without any major change in all the cars on the market, so that it is possible to minimize the opponent's retaliation during driving.
Overlap and sonority in complex onsets in Georgian
Authors: Crouch Caroline , Katsika Argyro
Published: November 2019

This study investigates the relationship between the sonority shape of complex syllable onsets and articulatory overlap between the constituent consonants in Georgian (Kartvelian, Georgia; geo). Sonority sequencing and related phonological phenomena can be analyzed as epiphenomena related to perceptual cue preservation. The current study builds on previous research on Georgian that shows that order of place of articulation affects degree of overlap between stop-to-stop sequences and relates this back to issues of recoverability of segments within the sequence, and expands on this research to include complex syllable onsets with segmental makeups other than, but including, stop-to-stop sequences. Specifically, we use electromagnetic articulography (EMA) to examine the movements of the tongue, lips, and jaw during the production of Georgian words that cross three sonority shapes (rise, fall, and plateau) with front-to-back and back-to-front orders of place of articulation. Preliminary analyses confirm that there is less overlap in front-to-back clusters than in their back-to-front counterparts. It is also shown that sonority shape significantly affects overlap measures in interaction with order of place of articulations. This points towards a systematic relationship between sonority and overlap, which is discussed within the context of perceptual cue preservation and recoverability [Work supported by NSF.]
Respiration in speech: Control, global and local effects
Authors: Demolin Didier , Yu Shi , Hassid Sergio
Published: November 2019

Breathing is essential to man’s ability to speak. The respiratory bellows provide the power to the vocal apparatus. Expiration in speech often continues until lung volume decreases below functional residual capacity. Speakers appear to achieve a compromise between ventilatory and speech demands on flow rates. The question addressed in this presentation is how is the relative constancy of subglottal pressure (Ps) achieved despite the continual change of relaxation forces? During speech an extra 6/10 hPa is sustained above atmospheric pressure to provide the energy to speak. As showed in the literature, external and internal intercostal muscles are the most important to regulate Ps, not the diaphragm. In speech, Ps is sustained by the expiratory muscles after the recoil of the lungs tissues. Global effects show, from data obtained with direct measurements, that the slight Ps declination in sentences is largely due to the system’s compliance and changes in glottal and oral resistance. Local effects such as those on trills and stress, where increases of 1–2 hPa are observed, are also accounted for by modifications in glottal and oral resistance. Our results show that Ps and F0 that are regulated by different controls (spinal and cranial nerves) interact in complex ways.
The scope of the kinematic effects of prominence in Greek
Authors: Katsika Argyro , Tsai Karen
Published: November 2019

It is well established that speech units under prominence present longer, larger, and faster constriction gestures than their non-prominent counterparts. However, little is known about the scope of these kinematic effects and how their scope interacts with prosodic boundaries. Previous research has mainly focused on the durational dimension (lengthening) and contrastive focus. The current study uses electromagnetic articulography (EMA) to investigate the scope of the kinematic effects of prominence related to non-contrastive focus as a function of stress position (word-initial, word-medial, word-final) and boundary type (phrase versus word boundary) in Greek. The kinematic dimensions examined are duration, position, velocity, and stiffness. Results from five speakers indicate that all kinematic dimensions affect the stressed syllable but also present both anticipatory and spillover effects. The strongest effect of the dimensions of duration and position is found within the stressed syllable, while the maximum of the velocity and stiffness effects is within the syllable that immediately follows the stressed one. Interestingly, when stress is final, the velocity and stiffness effects extend across prosodic boundaries, regardless of the boundary type, affecting the formation constriction of the first post-boundary consonant. A model of prominence is proposed within the framework of Articulatory Phonology. [Work supported by NIH.]
On the nature of working memory structures in phonological encoding
Authors: Masapollo Matthew , Smith Dante , Guenther Frank
Published: November 2019

Current model and theories of language and speech production commonly propose that speakers plan and execute sequences of phonemic segments by integrating and consolidating individual segments into cohesive memory structures or “chunks,” which reduces processing load and improves motor performance. Yet, there is no consensus on the nature of the chunks buffered in memory during serial speech planning. To identify these structures, we investigated the generalization of motor chunking from training to transfer utterances. During training, subjects repeated isolated syllables containing non-native consonant clusters. Subjects produced these syllables with increased accuracy and speed after training, indicative of motor learning. After learning, we tested for generalization under higher memory load by having subjects repeat pairs of syllables that overlapped to varying degrees with the practiced syllables. We observed complete transfer of performance speed improvements to novel syllables containing previously practiced clusters, but only if they were practiced in the same syllable position (onset or coda). Practicing the whole syllable, however, resulted in greater accuracy improvements compared to practicing just the clusters, regardless of syllable position. Collectively, these findings suggest that working memory utilizes a syllabic structural frame with different representations for the same phonemes in different frame slots.
Estimation of vocal fold geometry and stiffness from voice acoustics
Authors: Zhang Zhaoyan
Published: November 2019

Many speech applications require estimating vocal fold properties from the produced acoustics. While there have been many previous research on solving the inverse problem, they are often based on lumped-element models of phonation, whose model parameters are difficult to relate to realistic vocal fold properties. This study explores the feasibility of inferring physiologically realistic vocal fold properties, including vocal fold length, thickness, depth, anisotropic stiffness moduli, and the subglottal pressure, from the produced acoustics, using a three-dimensional phonation model and a Bayesian inference approach. To reduce the computational cost associated with the use of a three-dimensional model and the large number of inputs to be estimated, we explore the possibility of improving computational efficiency and estimation accuracy using the large amount of three-dimensional simulation data available from our previous research. Preliminary results show that joint likelihood probabilities can be reasonably estimated based on the available simulation data, significantly reducing computational costs of Bayesian inference. The approach is able to estimate the control parameters of voice production from the produced acoustics with reasonable accuracy. It is observed that certain control parameters, particularly vocal fold stiffness, consistently have large estimation errors than others. [Work supported by NIH.]
Effects of vocal tract geometrical differences on flow and sound of sibilant fricatives
Authors: Yoshinaga Tsukasa , Nozaki Kazunori , Wada Shigeo , Iida Akiyoshi
Published: November 2019

Sibilant fricatives are known to be produced by controlling a turbulent jet flow in a front part of the vocal tract. However, the manner of the control in each individual is still unclear. In this study, the vocal tract geometries of sibilant fricatives /s/ and /∫/ were extracted from magnetic resonance imaging (MRI) and large eddy simulation was conducted to clarify the relationship among the vocal tract geometries, flows, and acoustic characteristics. Five male Japanese subjects assumed a supine position in the MR machine, and images of the vocal tract were corrected while the subject was sustaining /s/ and /∫/. From the corrected images, computational grids were constructed, and large eddy simulation of compressible flow was applied to simulate both the turbulent flow and sound generation. Results of the simulations showed that the configuration of jet flow in each vocal tract was different, and the maximum amplitude of sound source distributed in different positions in the front part of the vocal tracts. By extracting the characteristic dimensions of each vocal tract, we found that a space between lower incisor and tongue constriction is important for the formation of individual acoustic characteristics of sibilant fricatives.
A real-time system for visualizing tongue position during vowel phonation
Authors: Wang Bernard , Smith Julius O.
Published: November 2019

A real-time system to estimate and visualize the position of the tongue during vowel phonation is presented. The system uses Linear Predictive Coding (LPC) to track formants F1–F3 of input speech frames. An algorithm proposed by Ladefoged et al. is used to map formants F1–F3 to tongue position [J. Acoust. Soc. Am. 64, 1027 (1978)]. 2-D visualizations of the tongue are created with cubic splines, which are rendered each input frame to create a real-time animation. The proposed system could serve as a pedagogical tool for language learners and singers by providing visual feedback of the inner mechanics of the vocal tract during vowel phonation.
Learning a representation of tongue dynamics from unlabeled ultrasound videos
Authors: Wang Hongcui , Roussel Pierre , Denby Bruce
Published: November 2019

Ultrasound imaging of the tongue has been used for decades in studies of speech production and speech motor control, for silent speech interfaces, and in numerous other areas. Despite substantial efforts, however, extraction of reliable features from ultrasound tongue data remains a challenge due to speckle noise and acoustic propagation issues. Recently, Representation Learning has emerged in a variety of fields as a powerful means of generating useful representations of underlying structure in raw, high-dimensional data. In its unsupervised form, Representation Learning discovers structures in unlabelled data, thereby eliminating the need for a time-consuming labelling step. The present work is believed to be the first use of unsupervised Representation Learning to reveal structures related to tongue dynamics in unlabelled ultrasound video. A 3-D Convolutional Neural Network examining a series of unlabelled 60 Hz tongue images is found to accurately predict unseen future images even for large interframe tongue displacements. By comparing the 3DCNN prediction error to that of a simple previous-frame predictor, tongue trajectories containing transitions between regions of acoustic stability can be identified and correlated with formant trajectories in a spectrogram. Prospects for leveraging the tongue dynamic representation for use in subsequent speech processing tasks will be discussed.
Compressive two-dimensional beamforming for localization of tip vortex cavitation
Authors: Park Yongsung , Gerstoft Peter , Seong Woojae
Published: November 2019

Noises induced by propeller tip vortex cavitation (TVC) have sparse sources near the propeller tip. Localization of these noise sources with sensor arrays involves the direction-of-arrival (DOA) estimation. Provided the noise sources are sparsely located, compressive sensing (CS) is used for two-dimensional (2-D) DOA estimation, which estimates both azimuth and elevation angles of the sources. With a planar array configuration, the 2-D DOA estimation problem is formulated in the CS framework and CS has shown less ambiguity and higher resolution capabilities compared to traditional DOA estimation schemes even under a single snapshot data. The superior performance of CS is demonstrated on experimental data from cavitation tunnel experiments. Two experimental data are considered. For the first experiment with one known source location, the true DOA has been estimated using CS. The second case involves initially intended TVC noises, and CS has estimated DOAs near the upper downstream area of the propeller, where TVC noises are generally generated.
Characterization of internal waves in SAS imagery via ray tracing
Authors: Pate David J. , Cook Daniel , Lyons Anthony P. , Hansen Roy E.
Published: November 2019

Synthetic aperture sonar imagery often captures features that appear similar to sand waves but are actually pockets of denser water traveling as isolated waves along the seafloor. These pockets of cold water refract acoustic waves like a lens, causing intensity peaks and shadows that resemble medium to large scale sand waves. This work uses dynamic ray tracing to predict the intensity return as affected by refraction. First, we explore the nature of the intensity pattern created by internal waves of various shapes and sizes. Then, we use an optimization-based approach to solve the inverse problem: given an intensity pattern, determine the size, shape, and location of the internal wave that created it.
Investigation of bathymetry problem using kinetic model
Authors: Liu Elizaveta R. , Sushchenko Andrei , Prokhorov Igor
Published: November 2019

In this paper, we investigate a bathymetry problem, the seabottom surface reconstruction, using side scan sonars. A sonar emits pulses of sounds and detects echoes. The sound waves bounce off the surface, and the sonar receives the backscattered signal. Gauging water depth, using acoustic technology, involves measuring the time taken for sound waves to travel between the vessel and the seabottom and back again. To describe sound propagation in a fluctuating ocean, a mathematical model, based on the radiative transfer equation, is used. The solution of the direct problem, consisting of determining the wave energy flux density, has been obtained in the single and double scattering approximations. Further, we consider inverse problem which involves the determination of the bathymetric function, which describes the seabottom level variation from the average horizontal plane. As a solution to the problem, a non-linear differential equation has been deduced under assumptions for the directivity pattern of the receiving antenna. An adaptive numerical method is developed for the analysis of the bathymetry problem. Computational experiments, showing the influence of a double scattering signal on the seabottom reconstruction, are conducted.
Broadband horizontal wavenumber estimation using block sparse Bayesian learning
Authors: Niu Haiqiang , Gerstoft Peter , Reeves Ozanich Emma , Li Zhenglin , Gong ZaiXiao
Published: November 2019

The horizontal wavenumbers are estimated by block sparse Bayesian learning for broadband signals received by a vertical line array in ocean waveguides. The dictionary matrix consists of multi-frequency modal depth functions derived from WKB approximation, which are associated with horizontal wavenumbers. The dispersion relation for multi-frequency horizontal wavenumbers is also taken into account to generate the dictionary. With the constraint of block sparsity, the sparse Bayesian learning approach is shown to extract the horizontal wavenumbers and corresponding modal depth functions with a high precision, while the prior of sea bottom information, moving source, and source locations is not needed. The performance is demonstrated by simulations and experimental data.