bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of tunable multistable metastructures
Authors: Hwang Myungwon , Ki Yeongeun , Arrieta Andres F.
Published: November 2022

Connectivity yields unconventional properties. However, the attainable dynamics are strongly dependent on the unit cell size, restricting the effective behavior to narrow, high-frequencies bands. This is due to the nature of band gaps from local resonance or scattering, both of which are strongly related to unit’s size (mass) and stiffness. We present multistable metastructures displaying strong nonlinear interactions between propagating transition waves and structural modes. We show how transition waves excite the same type of response in the metastructure’s units regardless of the input excitation. This invariant response allows for efficient electromechanical energy transduction as the mechanical response can be tuned to electrical conversion circuits robustly. We also present a new dynamic phenomenon—solitonic resonance—leveraging soliton-structural mode interactions that enable multistable metastructures to exhibit extreme input-output energy exchange. By tuning the topology of our multistable metastructures we can transform energy input frequencies into output responses orders of magnitude apart. The presented metastructures break the dependence of the attainable unconventional dynamical properties on the unit cell's size. The dynamics of multistable metastructure provide a route to accelerating metamaterials adoption in engineering applications addressing the structural bandwidth.
Braid feature extraction and representation of active sonar data
Authors: Kubicek Bernice , Sen Gupta Ananya , Kirsteins Ivars
Published: November 2022

As an active sonar system pings an object of interest, the moving platform collects data descriptive of both the target and background clutter. We hypothesize that the relevant features of the target echo tend to persist and smoothly morph over time in some domain as the sonar platform continues its route. This work leverages the preceding and presents initial findings of a feature extraction algorithm resulting in representations of active sonar data that persistently appear and are physically and statistically informed. This is done by isolating the targets’ features from background clutter using a statistically meaningful threshold, extracting features onto a manifold representation, and mathematically describing and quantifying the extracted features. The background clutter is modeled using a Rayleigh probability density function, and the echo is isolated by keeping statistically significant responses. Feature extraction is performed on a ping-by-ping basis by minimizing the angle between the isolated echo samples and assigning a pseudo probability to sequential samples. These methods are used to extract features from ping sequences that are unique to targets and quantified using a correlation metric. Results reported are on simulated data and experimental field data. [Work supported by NREIP, NDSEG, and ONR, Grant No. N00014-21-1-2420.]
Classification between different vocal pathologies by using convolution neural network and continuous wavelet transforms
Authors: Rathi Bhawna , Hsu Timothy
Published: November 2022

Millions of Americans suffer from vocal damage that can negatively impact their daily lives and potentially incur large health care costs. Vocal damage is found frequently in at-risk populations, including singers, teachers, coaches, and telemarketers. The current standard method of diagnosis involves performing a laryngoscopy. Current research has shown that digital signal processing with acoustic machine learning methods can be used to distinguish healthy from unhealthy voices, but there has been limited prior work in classifying different pathology types from one another using only acoustic machine learning and signal processing methods. This study aims to design a convolution neural network (CNN) algorithm that can differentiate between different vocal pathologies by using an audio data file of the vowel sound /a/ of damaged voices as inputs. The audio dataset of different vocal pathologies has been obtained from the Indiana University Vocal Pathology Dataset. For the CNN algorithm, images are required, and continuous wavelet transforms (CWT) are calculated that show spectral energy across time in a visual format. The overall results will show the accuracy for two class classifications of different vocal pathologies and how accuracy changes when the different parameters of the CNN architecture are changed.
Evaluating the reverberation chamber as a small room: How room dimensions affect the generalization of testing results
Authors: Way Evelyn
Published: November 2022

Testing acoustic properties is performed in specially designed reverberation chambers according to relevant ASTM, ISO, and other international standards. Performing this testing is complicated by the fact that practical considerations limit the size of the reverberation rooms. Where the dimensions of the room are similar in size to the wavelength of the frequency of interest, modal behavior becomes dominant, and the statistical analysis of room acoustics based on the diffuse sound field theory is not sufficient to characterize the sound field. However, standard methods implement formulas which assume a diffuse sound field to compare results from different labs. Using the Maxon Acoustics Lab, a purpose-built floor ceiling test lab comprised of two stacked, 300 m3 reverberation chambers, we will examine the various physical criteria for evaluating a theoretically diffuse sound field. Discussion will include historical debates concerning the validity of comparing measurements in different labs and an analysis of the Maxxon Lab through the lens of various methods for evaluating the acoustic environment in comparison to the statistical analysis for room acoustics. Methods will include analysis of modal density and distribution, sampling of the sound field per ASTM standards E90, E492, and C423, the Schroeder frequency, and other statistical analyses.
Influence of sound source directivity on finite element simulation of small-room acoustics
Authors: Zhang Zhichao , Yu Guangzheng
Published: November 2022

Numerical simulation is a flexible and effective method for room acoustic design. Full-range simulation of room acoustics requires a combination of different numerical methods, in which wave acoustic methods (WAM) and geometric acoustic methods (GAM) are used for the low and high frequency region, respectively. In the general low-frequency WAM simulation, a sound source is often assumed to be a point source or loudspeakers are usually approximated by circular planar pistons. However, compared to a large room, the critical frequency between WAM and GAM should be higher in acoustic simulation of small rooms because of relative size between the wavelength and the room, and thus, the above simplifications of actual sound sources, typically loudspeakers, may lead to errors in terms of directivity in the frequency range that the WAM is applied for. Further errors in the desired room impulse responses or other room acoustic parameters caused by directivity errors needs quantitative analysis, and then evaluation can be made on whether it is necessary to consider a more accurate sound source directivity in the WAM simulation of small room acoustics.
Evidence of 3D effects for along shelf acoustic propagation during SBCEX21
Authors: DeCourcy Brendan J. , Bonnel Julien
Published: November 2022

The 2021 Seabed Characterization Experiment (SBCEX21) was performed on the New England Shelf Break (NESB) in May 2021 with the main objective of characterizing the NESB sediment geoacoustic properties. In this talk, we focus on low-frequency propagation (f<100 Hz) along the 200 m isobath line. Time-frequency dispersion of normal modes is estimated using a SUS charge signal recorded on a distant single hydrophone TOSSIT system. Geoacoustic inversion is performed, but two-dimensional (2D) acoustic propagation models fail to capture the observed behavior of higher order acoustic modes, and predict much shorter travel times than are seen in the data. By introducing a three-dimensional (3D) model environment, both parabolic equation and modal ray calculations confirm that the gradual shelf slope has a nontrivial influence on modal travel times. This comparison between 2D and 3D simulations of SBCEX21 acoustics and experimental data emphasizes the importance of 3D effects from sloped bathymetry on understanding propagation in a shelfbreak environment. These effects will need to be accounted for when doing geoacoustic inversion of SBCEX21 along-shelf low-frequency data.
Changes to mixed layer acoustic energy from spice and isopycnal tilt
Authors: Richards Edward , Colosi John A.
Published: November 2022

Mixed layer acoustic propagation is predicted for fields that approximate two dynamically separate sources of sound speed variation: the tilting of isopycnals and “spice,” density compensated temperature and salinity changes. These fields are decomposed from a transect measurement over approximately 1000 km of the northeast Pacific Ocean. At a frequency with only one mixed layer mode, both fields contain blocking features, defined as sound speed structures less than 5 km wide that create significant acoustic energy loss. The transect shows two distinct regions where blocking features are caused by tilt or spice, indicating the acoustic importance of these dynamic processes depends on location. Statistics of mixed layer acoustic energy are investigated at two frequencies, averaging one or three mixed layer modes, both with and without blocking features. The spice field was found to produce higher loss than the tilt field. Both fields create more loss at lower frequencies when locations with blocking features were included, and more loss at higher frequencies without blocking features. Mixed layer mode amplitudes demonstrate more mixed layer modes at the higher frequency increases mode coupling, both preventing large scale acoustic energy loss and creating a more consistent loss mechanism.
Effects of modelling assumptions of complex ocean floor topography on marine life
Authors: Crowcombe James , Clarke Tim , Mather Yvonne , Williams Duncan
Published: November 2022

Passive acoustic monitoring (PAM) is an important technique to assess the presence of marine mammals and, if necessary, mitigate the effects of anthropogenic noise sources upon them. The complexity of the ocean acoustic environment makes accurate localisation of marine mammal vocalisations difficult. It is, therefore, important to be able to predict the detection and localisation performance of PAM to ensure sensors are optimally placed and any resulting actions are suitably informed. A variety of acoustic models can be used to predict the performance of a sensor field ranging from simple 1D models up to full 3D models. Each type of model has advantages and disadvantages. Simple 1D models offer the most advantages in terms of solution time and minimal inputs but their predictions can have reduced accuracy. This is especially true in areas of complex ocean floor topography, such as on a shelf break, where complex 3D acoustic effects can occur. This study investigates the variation in the predicted acoustic field from 1D up to 3D models on a shelf break and how with increasing model fidelity the picture of the acoustic environment changes and its impact on acoustic monitoring advice. © Crown copyright (2022), Dstl.
Simulations of shear wave propagation in tissue based on kidney transplant histology
Authors: Sanger Nicholas M. , Vasconcelos Luiz , Urban Matthew W.
Published: November 2022

End-stage kidney disease is the result of progressive declines in function and frequently requires a transplant. Maintaining kidney transplant health with regularly scheduled function tests or biopsies is necessary to adjust treatments. Ultrasound shear wave elastography (SWE) could provide an inexpensive, noninvasive modality to monitor allograft health. In this project, we built models of the kidney cortex from segmented kidney transplant histology images. We assigned viscoelastic properties, based on a Kelvin-Voigt model, to the major constituents, glomeruli, interstitia, tubules, and fluid and simulated the wave propagation through tissue with no disease, inflammation, interstitial fibrosis, and tubular atrophy. The resulting in silico wave motion in the time- and frequency-domains was characterized to compare the in silico and in vivo mechanical properties. We also attempted modeling the effects of perfusion by modifying the constituents’ viscoelastic properties. We found the most differentiation for shear elasticity, shear viscosity, and phase velocity dispersion in the inflammation patients. When accounting for perfusion we observed increases in shear wave group velocity, shear viscosity, and dispersion, bringing the results from in silico models in closer agreement with in vivo results. These results are encouraging and demonstrate first steps of simulating the shear wave propagation based on histological models.
Spectral-based cluster analysis of noise from collegiate sporting events
Authors: Cutler Mitchell C. , Cook Mylan R. , Transtrum Mark K. , Gee Kent L.
Published: November 2022

This paper presents on studies to characterize crowd response from recordings taken from 30 collegiate sporting events. Inferring crowd response from raw acoustic signals is challenging because they contain complex combinations of acoustic sources including crowd noise, music, individual voices, and PA system. First, the distributions of recorded half-second interval overall sound pressure levels from basketball and volleyball games, both men’s and women’s, are analyzed with regard to crowd size and venue. Using 24 one-third octave bands between 50 Hz and 10 kHz, half-second spectral levels from each type of game are then analyzed. Based on principal component analysis, 87% of the spectral variation in the signals can be represented with three principal components, regardless of sport, venue, or crowd composition. Using the resulting three-dimensional component coefficient representation, clustering analysis (using Gaussian mixture models) then finds nine different clusters. These clusters separate audibly distinct signals and represent various combinations of acoustic sources, including crowd noise, music, individual voices, and PA system.
Low-cost measurement-grade microphone powered by MEMS elements and preamplifier housed in 3D printed enclosure
Authors: Riccardi Peter J. , Rusk Zane T. , Case John A. , Park Heui Young , Rokni Eric , Thompson Stephen C.
Published: November 2022

Acoustic measurement-grade microphones with flat frequency responses and adequate sensitivities are a necessary tool for many acousticians and vibroacoustic engineers. These microphones can often cost hundreds, if not thousands, of dollars. With the availability of microelectromechanical systems (MEMs) microphone elements and 3D printers, it is possible to construct drop-in replacements of these measurement grade microphones at the fraction of the cost. A MEMs system was designed with four elements in parallel to reduce uncorrelated noise. The system runs rail-to-rail on a 3.3VDC, Integrated Electronics Piezo-Electric (IEPE) powered preamplifier, producing a nominal sensitivity of 13 mV/Pa. The microphone body is 3D printed, and the final bill of material cost is less than 30 USD. The performance of the microphone was measured experimentally in a semi-anechoic chamber and verified by comparing the data to measurements of a commercial microphone: the PCB Piezotronics 378B02 ½” free-field microphone with a nominal sensitivity of 50 mV/Pa. This presentation will show that the MEMs microphone has a similar electrical noise floor, and lower acoustical noise floor below 1 kHz. The frequency response of the MEMs microphone is flat in the audio band through 10 kHz, making it a suitable replacement for acoustical measurements where its lower sensitivity can be tolerated.
Combination tones and multiphonics in a physics of music lab
Authors: Worland Randy
Published: November 2022

Laboratory exercises related to multiphonic tones in wind instruments have been developed for use in an undergraduate Physics of Music class. Although the concepts of nonlinear mixing and production of combination tones can be challenging to present at a non-technical level, a hand’s-on (mouth’s-on!) approach allows students to can gain a visceral and aural appreciation of this type of mixing and its musical use by wind players. The exercises make use of inexpensive free-reed pitch pipes. A pair of pipes can be played independently, producing a linear combination of the two sources, and as a pair of coupled nonlinear oscillators, resulting in combination tones. The differences between the two types of mixing are heard and viewed on a spectrogram in real time. Unlike multiphonics produced by advanced woodwind and brass players, every student can produce these combination tones with pitch pipes. Most can also sing a fixed pitch while playing a pipe to achieve another multiphonic effect. The exercises are readily extended to harmonicas, as available, where difference tones are often heard quite clearly, and the nonlinear mixing forms an essential part of the instrument’s timbre. Additional multiphonic examples are also illustrated.
Uncovering the differences between the violin and erhu musical instruments by statistical analysis of multiple musical pieces
Authors: Song Wenyi , Horner Andrew B.
Published: November 2022

The violin and erhu are two of Western and Chinese music’s main bowed string instruments. Recent work has compared the different emotional characteristics between the violin and erhu on the Butterfly Lovers Concerto. In our study, we examine several hypotheses to investigate whether the previous studies’ results hold generally. Four musical excerpts were extracted from four famous Chinese and Western classical pieces, and the excerpts were divided into four emotional categories: Happy, Sad, Agitated, and Calm. Based on the Butterfly Lovers results, we expected that: (1) the violin has a more Happy emotional characteristic than the erhu, while the erhu is comparatively more Sad, and (2) the violin is better at conveying high-Arousal excerpts. We used the Bradley–Terry–Luce (BTL) paired-comparison model to obtain the ranking scores and identify statistically significant differences between the two instruments. The erhu was consistently perceived as sadder than the violin for all Sad excerpts, while the violin was generally calmer and more agitated for those categories. Further study with more listeners and excerpts is needed to verify whether these results generally hold and at a statistically significant level.
Analytical solution for a focused vortex beam radiated by a Gaussian source
Authors: Gokani Chirag A. , Meng Yuqi , Haberman Michael R. , Hamilton Mark F.
Published: November 2022

Current interest in focused vortex beams is motivated by the ability to trap particles axially and laterally using the resulting radiation force. A simple closed-form solution is obtained in the Fresnel approximation for a sound beam radiated by a Gaussian source with time dependence e−iωt, focal length d, amplitude distribution exp(−r2/a2), and azimuthal phase dependence einθ, where θ is the angle in the plane perpendicular to the beam axis, and the integer n is the topological charge, referred to here as the vorticity. The solution is in good agreement with the pressure field predicted in the paraxial region by numerical evaluation of the Rayleigh integral. Of interest in optics as well as acoustics is the distance from the minimum along the beam axis to the first local maximum, referred to as the vortex ring. The present solution yields rn = ηnd/ka for the vortex ring radius in the focal plane, where k is the wavenumber, and ηn = 1.69 + 0.965(n−1) for vorticities in the range 1 ≤ n < O(20). Within this range the radius rn thus increases linearly with the vorticity. Results are also presented for dependence of the focusing gain on the vorticity. [CAG was supported by the ARL:UT Chester M. McKinney Graduate Fellowship in Acoustics.]
Particle manipulation with acoustic waves based on Hertz-Mindlin mechanics
Authors: Terzi Marina , Tournat Vincent , Aleshin Vladislav , Chekroun Mathieu , Lanoy Maxime
Published: November 2022

Ultrasound noncontact particle manipulation (vibrotransportation) is of interest for a number of industrial applications: delivery of solid agents for defect healing, noninvasive excretion of undesirable particles, micromachine technology, and sorting of particles. It is known that a particle on a substrate can be moved by a combined action of acoustic waves and friction. A traditional theory describing the effect considers a particle as a material point capable of moving only against the wave, i.e., in a direction opposite to the wave propagation direction. Here, we use another approach based on Hertz-Mindlin mechanics in which a particle represents a deformable body whereas a zone of its contact with the substrate has a certain structure including evolving regions of stick and slip. The friction dynamics of the Hertz-Mindlin system with a mass comprises different regimes, including a consistent motion in a desired direction (not only the one opposite to the direction of wave propagation but also the one oriented like the wave), which allows a more elaborate manipulation or positioning of the particles. The presented numerical tool treats the problem of a particle on a substrate being moved by Rayleigh waves. We demonstrate various regimes in which steady movement is observed or not, depending on excitation parameters and particle inertia.
Noncontact rotation of a small object using ultrasound standing wave and traveling wave
Authors: Yamamoto Eimei , Nakaoka Natsumi , Koyama Daisuke
Published: November 2022

In an acoustic standing wave generated in the air between a vibrator and a reflector, a small object is levitated near the nodal positions of the sound pressure where the acoustic radiation force and the gravity are balanced. By controlling the sound field spatially and temporally, the object can be transported without contact. In this report, we experimentally investigated the non-contact high-speed rotation of a small object using ultrasound, which can be applied to measurement techniques of the physical properties of liquids. The experimental system consists of a vibrating disc with four bolt-clamped Langevin-type transducers and a reflector, and an acoustic standing wave is generated between them. The effects of the tilt angle of the reflector with respect to the vibrator on the rotation speed of the object and the acoustic field were investigated. When the tilt angle was around 1.2°, the object was trapped in the air at 31.5 kHz by the standing-wave component in the vertical direction and rotated by the traveling-wave component propagating in the horizontal direction. The maximum sound pressure amplitude and the rotation speed of the object were changed with the tilt angle, and a larger sound pressure amplitude gave a larger rotation speed.
Locating impulsive sound sources in microscale urban spaces
Authors: Davis Dorian , Gaye Samba , Mandjoupa Lirane , An Justin , Mahmoud Wagdy , Wang Lei , Denis Max
Published: November 2022

In this work, techniques for localizing impulsive acoustic sources in an urban environment are presented. Of particular interest is the localization of sources in urban street canyons and enclosed urban areas. Sound propagation in an urban environment is strongly influenced by multiple reflections. In urban street canyons, multiple reflections tend to amplify with decreasing canyon width. A numerical investigation is performed to study the role multiple reflections on time difference of arrival (TDOA) and beamforming source localization techniques. Results of various urban street canyon and enclosed space geometries are investigated. The results and limitations of the TDOA and beamforming techniques for estimating source position in urban environments are discussed.
Transfer function model-based Bayesian estimation of dissipation and sound speed in impedance tube measurements
Authors: Chen Ziqi , Xiang Ning
Published: November 2022

The air dissipation, mainly due to the boundary effect at interior walls of impedance tubes, is noteworthy for normal incidence measurements of acoustic materials using the transfer function method. This work proposes a transfer function model-based Bayesian approach to estimate the dissipation factors. Other parameters, such as the sound speed and the microphone positions, are also critical, therefore, estimated as well, along with the dissipation. The measurement of the empty impedance tube with a rigid termination applies the two-microphone transfer function method. A hypothetical air layer assumed in front of the rigid backing enables the numerical comparison between the air layer’s theoretical and experimental transfer function values. Experimental results incorporating the estimated dissipation coefficient validate the accuracy of the proposed approach. Furthermore, the estimated parameters are incorporated into further evaluations of material properties using the transfer function method, which effectively reduces the residual absorption error of the impedance tube measurement.
Examining a new paradigm for simultaneous evaluation of mismatch response (MMR) and complex auditory brainstem response (cABR) for speech in MEG
Authors: Zhao Tian C. , Taulu Samu
Published: November 2022

The mismatch response (MMR) is a common neural signature, both in M/EEG, to evaluate neural sensitivity to sound change. Furthermore, the complex auditory brainstem response (cABR) has gained wide research interest recently as it is argued to reflect early sensory encoding of complex sounds, such as speech, along the auditory pathway. While both measures are important in infants as babies undergo rapid speech learning, they also share the crucial drawback that it takes many trials and thus long recording times, prohibiting a wide usage in infant population. Here, we investigate a new and more efficient recording paradigm to simultaneously assess both MMR and cABR for speech in MEG. Adult participants are recorded under this new paradigm using simultaneous M/EEG with previously published speech stimuli. For MMR, we aim to replicate previously published results that MMR for a native speech contrast is more concentrated than for a nonnative speech contrast. For cABR, we aim to extract a predominant spatiotemporal pattern from all MEG channels and examine its correlation with the EEG-recorded signal. Once the new paradigm can be validated in adults, it can be used in infant populations with much increased efficiency, opening the door for addressing new research questions.
Suitability of online and offline remote recording for vowel reduction analysis
Authors: Conklin Jenna T. , Chuen Sophia
Published: November 2022

Increasing demand for remote research techniques has led to several initial investigations of the suitability of remote recording for vowel production research. An initial consensus has emerged that remote recording may provide broadly accurate data for broad-strokes analysis, such as analyzing the relative positions of a speaker’s vowels, although some minor distortions may occur; fine-grained analysis of sociolinguistic variation suffers greatly from remote data collection (Freeman and De Decker, 2021). This study investigates the quality of data obtainable through two remote recording methods (online recording through Gorilla and offline recording via smartphone) for a vocalic phenomenon requiring a medium level of sensitivity of analysis, namely vowel reduction. Ten subjects completed a shadowing task eliciting target words containing one of five English vowels in reduced or unreduced form, taking simultaneous online and offline remote recordings. To determine whether the variability introduced through the remote recording process was sufficient to alter the findings of the study, results were compared to data from a second group of subjects who completed the task in person in a traditional laboratory setting. This comparison to in-person data allows for an assessment of the suitability of online and offline remote recordings for vowel reduction research.
Lenition measures: Neural networks’ posterior probability versus acoustic cues
Authors: Wayland Ratree , Tang Kevin , Wang Fenqi , Vellozzi Sophia , Sengupta Rahul , Altman Lori
Published: November 2022

This study compared a new approach of lenition measure to traditional acoustic-based methods. In this new approach, degrees of lenition are estimated from posterior probabilities generated by recurrent neural networks trained to recognize the sonorant and continuant phonological features. These two phonological features capture the range of surface manifestations, from a fricative to an approximant, of lenited voiced and voiceless stops in Spanish. Input to the networks is Mel-filtered log-energy computed from 25-ms windowed frames of each 0.5sec chunk of the input signals. When applied to lenition of intervocalic voiced and voiceless stops, /p, t, k, b, d, g/, in the corpus of Argentinian Spanish built by Google, the new approach yielded lenition patterns largely similar to those obtained using a quantitative acoustic method. Specifically, both approaches revealed that voiced stops were more lenited than voiceless stops, that lenition was more likely in unstressed syllables relative to stressed syllables and that degrees of lenition vary with place of articulation of the target phoneme and the height of surrounding vowels. However, a greater amount of variance was accounted for by the absolute and relative (to neighbouring segment) intensity measures of lenition in the acoustic method than the phonological posteriors.
Towards developing speaker diarization for parent-child interactions
Authors: Murali Abhejay , Dutta Satwik , Chandra Shekar Meena , Irvin Dwight , Buzhardt Jay , Hansen John H.
Published: November 2022

Daily interactions of children with their parents are crucial for spoken language skills and overall development. Capturing such interactions can help to provide meaningful feedback to parents as well as practitioners. Naturalistic audio capture and developing further speech processing pipeline for parent-child interactions is a challenging problem. One of the first important steps in the speech processing pipeline is Speaker Diarization—to identify who spoke when. Speaker Diarization is the method of separating a captured audio stream into analogous segments that are differentiated by the speaker’s (child or parent’s) identity. Following ongoing COVID-19 restrictions and human subjects research IRB protocols, an unsupervised data collection approach was formulated to collect parent-child interactions (of consented families) using LENA device—a light weight audio recorder. Different interaction scenarios were explored: book reading activity at home and spontaneous interactions in a science museum. To identify child’s speech from a parent, we train the Diarization models on open-source adult speech data and children speech data acquired from LDC (Linguistic Data Consortium). Various speaker embeddings (e.g., x-vectors, i-vectors, resnets) will be explored. Results will be reported using Diarization Error Rate. [Work sponsored by NSF via Grant Nos. 1918032 and 1918012.]
Active target classification using a shallow neural network with dimension reduction
Authors: Byun Sung-Hoon , Choo Youngmin
Published: November 2022

Techniques for automatically identifying sonar targets using machine learning algorithms are being actively developed, and modern algorithms based on deep learning are often considered first. However, deep learning based algorithms require a lot of data to train a neural network, and if there is not enough data, overfitting easily occurs and the performance on real data can be degraded. In fact, in the case of active target detection where there is not enough data, it has been reported that using a shallow neural network after extracting appropriately designed features from the raw data showed better detection performance than applying deep learning directly to the raw data. With regard to this, we investigate the performance of a shallow neural network combined with dimensionality reduction techniques for active sonar target classification. In particular, several linear and nonlinear dimension reduction techniques are compared in terms of target classification performance, and the effects of the characteristics of background noise and the presence of reverberation on the target classification performance are discussed. [This work was supported by the research project PES4380 funded by KRISO.]
Real-time identification of airborne sound flanking paths using a 3-dimensional acoustic camera
Authors: Schmidt Andrew , O'Donovan Adam , Phillips Austin
Published: November 2022

Sound transmission testing, whether conducted in the laboratory or under field conditions, is critical for quantifying sound transmission performance of building constructions and elements. When samples undergoing sound transmission loss testing are constructed in the laboratory, results can suffer from airborne sound flanking paths that may not be apparent through visual inspection of the test sample. In the field, noise reduction testing between spaces can be similarly influenced by airborne sound flanking paths that are not immediately obvious. One methodology is presented utilizing a portable calibrated device that generates accurate overlays of sound pressure level over visual images (the VisiSonics 5/64 Acoustic Camera), allowing for the successful identification of unwanted flanking paths in both laboratory and field environments. Data are presented from recent laboratory testing that show the efficacy of acoustic imaging to identify sound flanking paths in real-time, enabling users to optimize sound transmission performance of an assembly.
Lateral impact noise II: Practice and recommended procedures
Authors: Lo Verde John , Dong Wayland , Rawlings Samantha
Published: November 2022

Impact noise insulation has traditionally been thought of mostly in terms of vertical adjacencies, and ASTM E1007 provides no guidance for performing such a measurement in a lateral, diagonal, or other non-vertical condition. Because lateral impact transmission can be significant, the authors have developed methods and practices for performing this measurement (see papers by the authors at ICSV 2017 and Inter-Noise 2019). ISO 16283-2 also describes procedures and methods for the measurements and analysis of lateral impact noise measurements. The various measurement methods are compared and evaluated. For some assembly types, there is an advantage to maintain a constant distance from tapping machine to the separating partition. Appropriate ratings for categorization of lateral impact isolation are discussed, and changes to E1007 to clarify the measurement method are proposed.
The use and application of pressure-based acoustical metrics adopted within the International Building Code
Authors: Rawlings Samantha , Lo Verde John , Dong Wayland
Published: November 2022

The 2021 International Building Code (IBC) includes pressure-based metrics as the field acoustical standards for conformance. These include normalized noise isolation class (NNIC) and normalized impact sound rating (NISR) (ASTM E336-20 and ASTM E1007-21, ASTM International; 2021 International Building Code, Section 1206, International Code Council). Pressure-based metrics were intentionally used in lieu of power based metrics. The authors here address why pressure-based metrics are more appropriate than power-based metrics for field verification, following from previous work [LoVerde and Dong, “Field impact insulation testing: Inadequacy of existing normalization methods and proposal for new ratings analogous to those for airborne noise reduction,” JASA 118, 638 (2005); LoVerde, Dong, and Rawlings, “Sound pressure-based ratings for evaluation of in situ sound isolation,” Denver (2022)]. Furthermore, the authors shall present the application of these metrics as they pertain to Building Code requirements. This paper will include and present code interpretation as it relates to sample size and evaluation for compliance as it relates to Building Code and sampling of systems for acceptance.
In situ testing methods for evaluating and predicting the impact isolation of high-performance floating floors - Part 1
Authors: Raley Michael , Allen Peter
Published: November 2022

Floating floors using discrete isolators are commonly recommended to mitigate impact noise from fitness facilities; however, there has been little study of the performance of floating floors under the types of heavy/hard impacts that often cause noise and vibration complaints from fitness facilities. Furthermore, it can be difficult to create mock-ups of floating floor systems for in situ testing, making it difficult to adequately evaluate their performance. Here, the authors present the beginnings of a research program intended to develop effective methods for evaluating and predicting the performance of floating floors using in situ testing methods. Part 1 of the presentation covers the overall scope of the research program, a discussion of prior work by others that informed the research program, an overview of the measurement setup and methodology, and a discussion of the methods to capture, post-process, and analyze the data.
In situ testing methods for evaluating and predicting the impact isolation of high-performance floating floors - Part 2
Authors: Raley Michael , Allen Peter
Published: November 2022

Floating floors using discrete isolators are commonly recommended to mitigate impact noise from fitness facilities; however, there has been little study of the performance of floating floors under the types of heavy/hard impacts that often cause noise and vibration complaints from fitness facilities. Furthermore, it can be difficult to create mock-ups of floating floor systems for in-situ testing, making it difficult to adequately evaluate their performance. Here, the authors present the beginnings of a research program intended to develop effective methods for evaluating and predicting the performance of floating floors using in-situ testing methods. Part 2 of the presentation covers the results of the measurements, including the effects of the following changes to the floating floor assembly: various air cavity depths, vented vs. un-vented air cavities, loaded vs. un-loaded floors, and concrete versus plywood floors. Finally, Part 2 presents the intended next steps in the research program.
Evaluation of dry mass timber assemblies and comparison to cementitious toppings
Authors: Callaghan Aedan , Golden Matthew
Published: November 2022

Mass timber construction is an increasingly common way of building taller and larger wood buildings utilizing renewable building materials with lower embodied carbon. Given the desire for the aesthetic design of exposed mass timber ceilings, it is common for these mass timber panels to require an additional subfloor decoupled by an acoustic interlayer to achieve IBC 1207 requirements. In the efforts to minimize added structural weight and overall embodied carbon, various dry linings were tested as an alternative to traditional cementitious toppings. A 175mm cross laminated timber (CLT) panel was constructed in the laboratory, and numerous ASTM E90 and ASTM E492 tests were performed. This analysis examines the role of dynamic stiffness of the acoustic interlayer and various mass layers in the resulting performance. Assembly transmission loss data from ASTM E90 testing are assessed to understand if it agrees with mass law.
Investigating the integration of biosonar sensing and flight control in bats on Borneo
Authors: Müller Rolf , Beiter Benjamin C. , Blackman Trinity , Hu Yihao , Goldsworthy Michael , Granger Jesse , Patterson Grant , Sequeira Yohan , Tuninetti Amaro , Tyler Adam , Webster Cara
Published: November 2022

Many bat species rely on biosonar as their primary source of sensory information about their environments. Species that are able to navigate amid dense vegetation use this biosonar information to guide highly dexterous flight maneuvers. Understanding the connection between biosonar inputs and flight outputs poses a challenge, because the flight apparatus of bats has the most degrees of freedom of any flight system—whether natural or man-made. At the same time, the biosonar inputs consist of just two one-dimensional acoustic time signals (i.e., echoes received at the two ears). Due to the complexity and large variability in the echoes and the flight maneuvers of bats, understanding the input-output relationships requires the ability to collect large amounts of quantitative data on the acoustics and the flight kinematics. In addition, comparing different bat species could offer a window into the principles behind the evolutionary co-adaptation of biosonar and flight. To accomplish this, a cylindrical flight tunnel that integrates synchronized arrays of 50 high-speed video cameras and 32 ultrasonic microphones has been set up on the island of Borneo. This instrument is complemented by a set of custom deep-learning techniques that can handle the large amounts of data that are being produced.
Machine learning methods for reconstructing the acoustic fields of bat biosonar
Authors: Sequeira Yohan , Tuninetti Amaro , Goldsworthy Michael , Müller Rolf
Published: November 2022

Understanding the relationships between biosonar and flight in bats requires synchronized recordings of the echo inputs and the flight kinematics of the animals. Here, integrated arrays of 50 high-speed camera and 32 ultrasonic microphones have been set up to collect the data that is necessary for achieving this goal. The arrays are set up to record bats as they fly through an an obstacle course inside a cylindrical tunnel. Due to the complexity of the received signals in these scenarios, we have been developing custom strategies that rely on a combination of compressed sensing and deep learning to reconstruct the acoustic field inside the tunnel from the microphone-array measurements. By using a combination of the high-speed video and acoustic data, it can be attempted to determine the bat's location in the array from the image data and then reconstruct the properties of the sound fields that were emitted and received at this position using the acoustic array data. The goal of this research is to eventually determine the dynamic characteristics of the bat's biosonar emissions such as beampatterns and potentially time-variant characteristics as well as the biosonar inputs that the bats rely on for controlling their flight behaviors.
Optimization approach to designing a bioinspired bat robot for flight and sonar integration
Authors: Beiter Benjamin C. , Sequeira Yohan , Tyler Adam , Blackman Trinity , Müller Rolf
Published: November 2022

In addition to remarkable acoustic sensing and navigation abilities, bats are highly agile and capable fliers, achieving flight efficiency that exceeds that of not only the rest of the animal kingdom, but of all robots as well. We seek to design a robot inspired by the biological capabilites of bats to achieve artificial flapping flight integrated with an acoustic sensing ability. Coupled with the kinematic and dynamic data collection array, we define a process for optimizing the design of bat wings for efficient flight. We identify fitness functions such as flap speed and air subtended throughout a wing cycle and then optimize the size and shape of a wing to achieve desired setpoints of the fitness functions. An inverse kinematics design process can then be used to create a single degree of freedom cyclic mechanism that will achieve the desired wing flap and fold functions. By setting fitness function objectives for both engineering design requirements (weight, lift, aerodynamics) and biologically inspired goals (wing flexibility, similarity to bat flight, responsiveness to echolocation). With this we can procedurally design a bat robot based on updating understandings of bat flight and navigation, leading to a streamlined production process when combined with rapid manufacturing.
Statistical and spatial characteristics of ocean ambient noise up to 1900 Hz on the Chukchi Shelf in the Arctic affected by climate change
Authors: Fung Kathryn , Bonnel Julien
Published: November 2022

This paper analyzes a year of underwater ambient noise data recorded in the Arctic on the Chukchi Shelf as part of the 2016–2017 Canada Basin Acoustic Propagation Experiment (CANAPE). A broadband (50–1900 Hz) statistical study is performed to analyze noise variability and its relationship to environmental drivers, notably the local presence of ice and the presence/absence of the Beaufort duct in the experimental area. Both environmental factors are found to significantly affect the noise levels. Local ice coverage tends to decrease ambient noise at all frequencies, while the presence of the Beaufort duct tends to increase ambient noise for frequencies below 1 kHz. The lowest ambient noise levels are, thus, found when the sea is ice covered, but the duct is absent. Furthermore, the study explores the link between noise level and distant ice drift magnitude. The ambient noise levels are shown to be highly correlated with distant (up to 1400 km) ice drift for frequencies between 300 and 1500 Hz. [Work supported by the Office of Naval Research.]
Shipping noise modelling in the thawing Arctic Ocean
Authors: Heaney Kevin D. , Seger Kerri D. , Verlinden Christopher , Heaney Andrew
Published: November 2022

One of the earliest and clearest signals of the impact of anthropogenic induced climate change has been the severe reduction in sea ice extent in the Arctic Ocean, particularly in the summer. Predictions of an ice free summer range from 2030 to 2050. The reduction of ice extent and thickness opens the possibility for greater shipping traffic through polar regions for international shipping (cutting the transit time from Europe to Asia), for mine and indegenous nations logistics support and for high north fishing. The increased number and presence of ships is a potential threat to the sensitive marine species that live in the arctic and have evolved in a region devoid of anthropogenic sounds. Effective management of the region requires an understanding of the potential increases in shipping noise levels and in their relative levels to natural backround sound, such as wind and ice noise. In this paper, we present a modelling study of 2013–2019 shipping noise and look to build a model to predict the shipping noise in 2030 based upon the combination of national forecast economic plans and ice modeling. Mapping the projected levels of shipping noise into excess noise (level above wind and/or background ice levels) provides a methodology for developing management decisions consistent with other noise measurement and mitigation projects. Comparison of models with passive observations of arctic soundscapes will be presented.