bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-time swarming detection in honeybees: Leveraging audio signal processing and machine learning techniques
Authors: Ardekani Iman , Pour Soheil , Sharifzadeh Hamid
Published: November 2023

Acoustical signals play a significant role in honey bee communication across various behavioral contexts. One notable example is queen piping, which refers to the acoustic signals emitted by young queens during the swarming process. Specifically, emerged virgin queens emit a distinct acoustic signal known as “tooting.” Tooting signals typically consist of one or two pulses lasting approximately one second, characterized by an initial rise in both amplitude and frequency. Recognizing these signals is of utmost importance for beekeepers as it enables them to identify an imminent swarm, effectively manage the swarming process, and safeguard the colony. This paper proposes a novel method for online swarming detection in honey bees, leveraging audio signal collection, acoustical signal processing, and machine learning techniques. The experimental results demonstrate the effectiveness of the proposed system in accurately detecting swarming at its early stages. Notably, the system maintains a high level of accuracy even when confronted with environmental noise and other unfamiliar audio signals that could potentially corrupt the audio signal acquired from the beehive.
Toward assimilation of acoustic travel times into an ocean state estimate
Authors: Escobar Ivana , Heimbach Patrick , Habbal Feras
Published: November 2023

Direct ocean observing systems are a scarce set of data that build the backbone for understanding the current state of the ocean. These systems are limited in areas of high variability in temperature and salinity. Pioneering work of Wunsch (1977) proposed efforts to extract detailed hydrographic information using sound propagation through the ocean, providing the scaffolding to improve our understanding of the ocean's interior. The integrated nature of such measurements makes acoustic thermometry a powerful application for monitoring regional to basin-averaged hydrographic changes in the ocean, a measurement that is difficult to achieve by individual “point” measurements (moorings, ship-borne CTD casts, or autonomous floats) alone. This work models acoustic travel times corresponding to eigenrays between a fixed source and receiver from an evolving ocean state. Inclusive computation of acoustic travel times within a dynamically evolving modeled ocean state provide a novel approach to model data comparison within a general ocean circulation model. An adjoint assimilation framework combines observations with numerical models to estimate and update oceanic state variables Forget et al. (2015). This process provides the necessary operators for model data comparison of ocean acoustic observable quantities within a consistent state estimation framework allowing for data assimilation from acoustic tomography measurements.
Boundary Pass Underwater Listening Station—Data management and processing
Authors: Hannay David E. , Grooms Connor , Li Zizheng , Quijano Jorge
Published: November 2023

The Boundary Pass Underwater Listening Station, sponsored by Transport Canada, Port of Vancouver and JASCO Applied Sciences, has continuously operated two compact tetrahedral hydrophone arrays beneath the busy shipping lanes leading to Vancouver, Canada since June 2020. The arrays are deployed 300 m apart on the seabed at 190 m depth and are cabled 2.6km to shore. A high sample rate of 512 kHz on all eight channels, with 24-bit samples, produces almost 400 TB/yr of raw acoustic data. Automated real-time data analysis calculates ambient noise statistics, detects marine mammal sounds, measures underwater radiated noise of individual ships, and creates spatial noise maps of the hulls of some vessels passing closely overhead. The derived data products are stored in an easy-to-maintain online database of just a few TB/yr. Results in graphic, tabular and compressed audio formats are made available to scientists and project managers through an intuitive web interface. The project follows international standards for ship noise and ambient noise calculations, so the results can be compared with measurements made elsewhere.
Noninvasive measurement of lung elastic properties
Authors: Zhang Xiaoming
Published: November 2023

Many lung diseases are associated with dramatic changes in mechanical properties of the lung. Chest radiographs and computed tomography (CT) are the most common clinical methods for evaluating lung disease, but they are expensive, use radiation, and do not measure lung stiffness. Shear wave elastography (SWE) uses ultrasound radiation force (URF) to generate wave propagation in the tissue. However, URF should not be applied to the lung, because there are air and blood in the alveoli. Relatively high-intensity ultrasound can cause alveolar hemorrhage and lung injury. We have developed a noninvasive, and clinically feasible technology, lung ultrasound surface wave elastography (LUSWE), that is capable of measuring lung elastic properties with speed and accuracy. LUSWE uses a handheld shaker to generate a local small harmonic vibration on the chest surface. The resulting wave propagates through the intercostal muscle and propagates on the lung. The surface wave speed is noninvasively measured using an ultrasound technique. LUSWE is safe because diagnostic ultrasound is only used to detect the wave propagation along the lung duo to mechanical wave generation on the chest. LUSWE may be used to assess multiple lung disorders such as lung fibrosis or lung edema.
State of the art in diagnostic lung ultrasound, from physics to clinics
Authors: Demi Libertario
Published: November 2023

Starting from the new international guidelines and consensus on the use of lung ultrasound, which have been published in 2023 [https://doi.org/10.1002/jum.16088], and by presenting the latest clinical results on quantitative lung ultrasound spectroscopy, this lecture will discuss the key technical challenges ahead for the field of lung ultrasound (LUS). These concerns the development of standardized imaging protocols and scoring systems, the application of AI-driven solutions to the analysis and classification of LUS data, the applicability of numerical wave propagation models, the design and fabrication of controllable and reproducible lung mimicking models, the understanding of the dominant physical mechanisms at play in the interaction between ultrasound waves and lung tissue, and the development of dedicated and quantitative solutions for the monitoring and diagnosis of lung diseases.
Delivering wireless ultrasound energy to remote systems: Design implications for powering medical implants requiring milliwatt versus several watts of power
Authors: Makin Inder Raj S. , Jaeger Paul , Jabs Harry , Ryan Thomas P. , Mast Douglas , Radziemski Leon J.
Published: November 2023

Current medical device technological advances either involve, miniaturization or wireless operation or both. Miniaturization enables implant placement closer to target organs, e.g., blood vessels, viscera, or neurological structures, while wireless powering of larger left-ventricular assist devices (LVAD) is desired to mitigate infection risk due to wires. Ultrasound is a viable energy modality, wirelessly propagating through material media (tissue) and either directly powers systems, or charges an integrated battery. Whether powering implantables, or non-implantable systems, such as digital devices, ultrasound power transfer approaches have to be application-specific. This talk will present data and development strategies for four distinct use-cases requiring respectively, <5 mW (miniaturized systems), ∼500 mW (implantable pulse generators, IPG), ∼2 W (non-implanted digital systems), and ∼8 W (LVADs). Choice of low-MHz frequency, planar single-element or coarse array transmit sources, as well as application-dependent receivers a few wavelengths in size (low-mW), to 45 mm diameter (∼8 W), will be described. Benchtop experiments demonstrate successful ultrasound charging of a miniaturized solid-state (250 mAh) battery within 20 minutes. Results from live porcine model studies show a 200 mAh Li-ion battery within a Ti-shelled IPG, being successfully charged without thermal-effect-related tissue changes in the propagation path. [Work partially supported by NIH/NIBIB R43EB019225.]
Hardware accelerated ray-tracing in ocean acoustics
Authors: Battle David J. , Vlaskine Vsevolod
Published: November 2023

Due to the expense and complexity of real-world data collection, machine learning applications in ocean acoustics demand ever-faster and more realistic models for training. In this talk, I discuss some recent GPU technologies which support hardware accelerated ray tracing and how they can be exploited to boost the throughput of certain types of calculations. Firstly, I describe RTX-Prop, which is a large-scale range-dependent Gaussian beam model which benefits from hardware-acceleration of bounding volume hierarchy searches and geometry intersection calculations. Designed to ingest oceanographic forecasts from the Royal Australian Navy’s Bluelink system, RTX-Prop has been developed as an embedded model to support tactical decisions by autonomous underwater vehicles. In the second application, I discuss hardware acceleration in the context of high-frequency sonar simulation. By synthesising fine-scale environmental detail, we have previously shown that simulated imagery can be almost indestinguishable from real data. Simulated sidescan and SAS imagery from our S4 model has recently become the basis of a machine-learning pipeline for training detectors and classifiers for naval mine countermeasures. [Work supported by the Trusted Autonomous Systems Defence Coorperative Research Centre.]
Numerical simulations of drill-string responses for downhole acoustic telemetry
Authors: Zhao Ao-Song , He Xiao , Chen Hao
Published: November 2023

In petroleum engineering, one major challenge for logging while drilling is that the transmission rate of downhole telemetry is too low for real-time evaluations. Downhole acoustic telemetry (DAT) uses acoustic guided waves in a drill string with periodic structures to transmit measurement data, expected to break through low-speed telemetry limitations. However, the lack of effective modeling methods makes the channel response difficult to predict, severely restricting equipment development and field applications. We propose a novel modeling approach to study the responses of the DAT channel. Excitation and propagation mechanisms of the mode waves in the DAT channel are investigated. The 2-D modeling issue is approximated to the 1-D plane-wave propagation along the borehole, considering transmission, reflection, and interconversion of the drill-string and fluid waves. The coefficients of each wave component and the full-wave channel function are derived from the transfer matrix. The efficiency and accuracy of the proposed means are validated by comparison with the finite difference. Numerical results show that the fluid-solid coupling leads to a generalized multipath effect in the DAT channel, making the acoustic responses exhibit discrete bandgaps and nonlinear phase distortion. This study provides a basis for frequency band selection and design for DAT systems.
Construction site environmental pollution management—Initiatives and innovation in South East Asia
Authors: Lamort Charles-Etienne
Published: November 2023

The management of pollution, and in particular of the impact of noise and vibrations, is very important for construction activities, even more so when it comes to urban construction sites. Indeed, some operations have a very significant emissive potential and it is appropriate, for the proper conduct of the activities, to adopt a certain strategy in order to control the impacts and thus ensure the good acceptance of the construction by the neighborhood. Environmental monitoring is the key to achieving this dual objective: prevent pollution and communicate. This article shows some initiatives adopted in South East Asia and illustrates how recent innovations using AI support work supervisors.
Improved spatial-temporal sound perception using active MEMS
Authors: Gutschmidt Stefanie , McKendry Alexandra , Cameron Christopher , Hayashi Seigan
Published: November 2023

Current microphone technology is based on a transducer concept that is the same for all end user groups, namely, passive, linear. While most of the technology-related challenges have been overcome by sophisticated post-processing algorithms, some of the current limitations of sound detection technology, especially as recognized by groups dealing with hearing impairments and losses, should be addressed at the transducer stage. In this work we present the dynamic behaviour and performance of an active, nonlinear MEMS sensor subject to acoustic stimuli and noise. Our work includes the presentation of a reduced-order model of the composite MEMS structure, relevant dynamic analyses including bifurcation and stability diagrams, as well as experimental investigations. Simulations and experimental results demonstrate cochlear-like amplification properties, meaning that soft signals are amplified significantly different from louder signals. Signals which initially are imbedded in a noise floor can be amplified without also amplifying the noise and thus providing another way of detecting sound patterns.
The puzzling soundmark of a cultural and tourism city: The case of Yogyakarta
Authors: Mediastika Christina E. , Sudarsono Anugrah Sabdono , Utami Sentagi Sesotya , Ariyanto Yusuf , Setiawan Teguh , Yanti Ressy Jaya
Published: November 2023

Yogyakarta is a city rich in culture and heritage, making it the second tourist destination in Indonesia after Bali. However, unlike Bali, Yogyakarta losses its intangible uniqueness quicker. This paper explores societies' and stakeholders' perceptions of Yogyakarta's soundscape, particularly the vanishing soundmark. Quantitative and qualitative approaches were employed to collect data through questionnaires and focus group discussions. Quantitative data were processed using a modest statistical method to show trends, and qualitative data were processed using the Colaizzi protocol. Quantitatively, respondents stated that the sounds of gamelan (a set of traditional musical instruments) and andong (horse-drawn carriages) are two soundmarks of Yogyakarta. They also recognize a third soundmark, namely the mystical sound of a marching band heard at certain times, whose origins are still debated. It truly represents the term “intangible.” Through the FGD, the discussants revealed that determining the iconic sound is intricate. It needs consent on what “icon” means because different areas have unique sounds. However, they agreed that Maliboro is still the most iconic place but has lost its soundmark due to traffic noise. The challenging part in developing soundscapes and soundmark is the varying perceptions between residents, visitors, and generations about the pleasant and memorable sound.
Urban Soundscape: White-vented Myna choruses on Zhongqing road
Authors: Chen ChihHsuan , Tsaih Lucky
Published: November 2023

Urbanization has impacted both humans and birds, and certain bird species, like the white-vented myna choruses on Zhongqing Road, have adapted to human-dominated environments. A study in April 2023 utilized cameras and sound level meters to document this phenomenon. Two phases were conducted: the first phase recorded white-vented mynas' departure and return times at dawn and dusk, along with the sound pressure level of birdsong. The second phase measured indoor sound pressure levels during peak birdsong at nearby buildings. Additionally, a questionnaire assessed people's perception of the bird choruses. Results indicated that birdsong at dawn had a lower sound pressure level (68.8 dBA) compared to dusk (75.4dBA), but it persisted longer. The dominant frequency was around 3150 Hz. Three out of four indoor sites exceeded the regulatory standard of 60 dBA. The questionnaire showed that over 75% of nearby residents disliked the bird choruses, while 18% of passersby found them interesting and potentially attractive for visitation. In conclusion, urban bird choruses can impact indoor acoustic environments and lead to negative perceptions among residents. This study aimed to provide quantitative data and insights into residents' listening impressions of bird choruses on Zhongqing Road, offering valuable reference data for stakeholders.
Deep reinforcement learning for optimal sound absorbing structures design
Authors: Gebrekidan Semere B. , Marburg Steffen
Published: November 2023

Deep learning algorithms have demonstrated a tremendous success in designing structures that surpass human capabilities. Based on the recent achievements of deep reinforcement learning in surpassing human capabilities, this paper focuses on implementing these algorithms to design optimal configurations of solid and porous materials that achieve a broadband absorption within the frequency range of 300 Hz to 3000 Hz. We employ model-free approaches, specifically deep Q-learning, double deep Q-learning, and dueling deep Q-learning algorithms, to predict material configurations that optimize absorption without requiring expertise knowledge. From a 230×30 different material combinations, the deep reinforcement algorithms learn to predict configurations that yield optimal absorption in few hundred steps. We discuss further the superior performance of a dueling deep learning algorithm compared to the other two deep learning approaches and a heuristic approach, such as genetic algorithm. The proposed model-free algorithms enable the prediction of absorption performance for any material configurations without the need for expertise.
An Ideal-observer standard for evaluating relative cue reliance
on multi-talker speech segregation
Authors: Lee Jungmee , Zandona Michael , Lutfi Robert
Published: November 2023

Modern hearing research identifies the ability of listeners to segregate simultaneous speech streams with a reliance on three major voice cues, fundamental frequency, level, and location. Few of these studies, however, present cues simultaneously as in natural listening, and fewer still consider the relative reliance listeners placed on these cues owing to the cues’ different units of measure. In the present study, trial-by-trial analyses were used to isolate listener reliance on the three voice cues presented simultaneously, with the behavior of an ideal observer (Green and Swets, 1966, pp. 151–178) serving as standard for determining their relative reliance. Listeners heard on each trial a pair of randomly selected, simultaneously recordings of naturally spoken sentences. One of the recordings was always from the same talker, a distracter, the other, with equal probability, was from one of two target talkers differing in the three voice cues. The listener’s task was to identify the target talker. Among 33 clinically normal-hearing adults only one relied predominantly on voice level, the remaining were split between voice fundamental frequency and location. The results are discussed regarding their implications for the common practice of using target-distracter level as a dependent measure of multi-talker speech segregation.
Adaptation to sentences and melodies when making judgments along a voice/non-voice continuum
Authors: Gao Zi , Oxenham Andrew J.
Published: November 2023

Perceptual contrastive adaptation effects can be used to identify important perceptual features or categories. Our previous work revealed contrastive adaptation effects between voice and non-voice categories when adapting with repeated single vowels or musical tones. The current study investigated whether the effect generalizes to adaptors with higher ecological validity—sentences and melodies. Ten-step continua between a “voice” (female /a/, /o/, or /u/ vowels) and an “instrument” (bassoon, horn, or viola) were generated for each possible pair. A sentence spoken by a female voice, or a melody played on bassoon or horn, was presented, followed by a test stimulus from along the continuum. Contrastive adaptation effects were observed, with the test stimulus more likely to be identified as a voice following a musical melody and vice versa. Pilot data showed similar trends when the female voice adaptors were replaced with their male counterparts, suggesting that the effects may generalize across speaker gender and fundamental frequency. The results show that contrastive adaptation to voice and non-voice stimuli is a robust effect that does not rely on the repetition of simple adaptors or on a shared frequency range between the adaptors and test stimuli. [Work supported by NIH grant R01DC005216.]
Modeling of auditory nerve fiber input/output functions near threshold
Authors: Bruce Ian C. , Buller Abigail , Zilany Muhammad S.
Published: November 2023

The instantaneous discharge rate of auditory nerve fibers (ANFs) near their threshold exhibits an approximately exponential relationship to the instantaneous pressure at the eardrum after compensating for the discharge latency. Some simplified models of the pressure-to-discharge transduction process in the cochlea have attributed this exponential relationship to an inner hair cell (IHC) transduction current that is either an exponential function with a level-dependent slope parameter or a first-order Boltzmann function (which is approximately exponential around the zero-input point) followed by a low-pass filter. However, such IHC transduction functions do not produce level-dependent changes in the AC and DC components of the IHC potential that match the behavior observed in physiological recordings. In this study, we show that retaining the physiologically-accurate IHC transduction model of Bruce et al. (Hear. Res., 2018) and following it by an exponential or exponential-like function that maps the IHC potential to the input of the synaptic power-law adaptation in that model produces the desired exponential input/output behavior near threshold while preserving the appropriate level-dependent changes in ANF discharge rate and phase-locking. [Work supported by NSERC Discovery Grant #RGPIN-2018-05778.]
Voltage-dependent bundle motion in mammalian auditory hair cells
Authors: McGrath Jamis
Published: November 2023

Auditory hair cells have bundles of protrusions on their surface held together by proteinaceous links. Sound-induced vibrations deflect these bundles, transferring force through the links to open nearby mechanically sensitive ion channels and providing our sensation of sound. An increase in bundle compliance caused by channel gating can also be detected as motion. The channels open during depolarization and the bundle moves rapidly toward shorter stereocilia, followed by a larger but slower movement toward the taller stereocilia. To determine how voltage changes affect mammalian inner hair cell (IHC) bundles, we used whole cell patch clamp and high-speed imaging to apply electrical stimulation and measure bundle motion. We found two components in the motions of freestanding IHC bundles in response to depolarization, a fast offset away from the tallest row and a slower movement back toward the tallest row. Like in turtles, the slower motion was sensitive to channel block and suggested ion flux, particularly calcium, played a role. Our findings show IHCs can rapidly respond to changes in the bundle setpoint without ion influx. This work improves our understanding of the mechano-electrical transduction process and helps address the controversial role of calcium in regulating the channel current response.
Towards the origin of devotion and happiness: An acoustical and neuro-cognitive exploration of Indian spiritual music
Authors: Banerjee Archi , Basu Medha , Sanyal Shankha , Patnaik Priyadarshi
Published: November 2023

Since the age of the Vedas, devotion has remained a key component of Indian music through centuries of changes and foreign influences. The brightest example of this is the Bhakti tradition, a pan-Indian movement (7th-15th Century CE), which integrated poetry and music in the transmission of spiritual and social goals. Devotees often report perception of emotions like devotion, happiness, awe while listening to spiritual music of their own religion and culture. This paper aims to study the acoustical and neuro-cognitive correlates of these emotions for two Indian spiritual music traditions – (a) Sikh Gurbani/ Shabad Kirtan, (b) Bangla Vaishnav Kirtan, both of which emerged from the Bhakti tradition. 5 Punjabi and 5 Bengali speaking participants listened to 3-minute long four songs from these two spiritual music traditions while EEG signals were recorded from each participant along with their emotion responses. Acoustical time series of these music clips and their corresponding EEG signals were analysed using nonlinear DFA technique. DFA Scaling Exponent values were calculated for multiple 30-second EEG segments across the total duration of each music clip to understand the perception and induction process of devotion and happiness in human brain, which is a novel step in the domain of music cognition and signal processing.
Does harmony function emerge from sequential notes in a diatonic mode? An event-related potential study
Authors: Zhang Shicheng , Fujioka Takako
Published: November 2023

Harmony can be implied by scales in Western tonal music. This phenomenon has been named chord-scale theory in modern jazz practice. However, neurological evidence of such interaction remains unclear. Previous research utilized Event-Related Potentials (ERP), such as Early Right Anterior Negativity (ERAN) and N5, to study sound expectancy violations and the harmony integration process. The current study investigates whether sequential musical notes arranged in an ascending diatonic mode (1) violate the sound expectancy and (2) alter the harmonic function of the target chord. We designed a musical sequence, namely Prime A (chords) + Prime B (ascending scale notes) + Target (a chord). Prime A and B set up global and local tonality accordingly. We hypothesized that the processing of the target chord would be influenced by Prime B in the harmonic dimension. For instance, a Neapolitan sixth target chord (F, Ab, and Db) is incongruent under C Ionian but could be congruent with C Locrian or C Phrygian. We found ERAN and N5 amplitudes at the target chord are altered by (1) the implied harmonic degree of the local tonality and (2) the relative distance between the local and global tonality in the circle of the fifth space. Our results suggest that Western listeners' brains can interpret musical notes from diatonic mode as part of harmony processing and integrate them into complex tonal music contexts.
Speaker embedding space cosine similarity comparisons of singing voice conversion models and voice morphing
Authors: Liu Elaine M. , Yeh Jih-Wei , Lu Jen-Hao , Liu Yi-Wen
Published: November 2023

We explore the use of cosine similarity between x-vector speaker embeddings as an objective metric to evaluate the effectiveness of singing voice conversion. Our system preprocesses a source singer’s audio to obtain melody features via the F0 contour, loudness curve, and phonetic posteriorgram. These are input to a denoising diffusion probabilistic acoustic model conditioned with another target voice’s speaker embedding to generate a mel spectrogram, which is passed through a HiFi-GAN vocoder to synthesize audio of the source song in the target timbre. We use cosine similarity between the converted audio’s speaker embedding and that of the target voice as an objective metric in two tasks. First, we show that we can morph between two voices: a smooth transition between two speaker embeddings in latent space results in a smooth transition of timbre in generated audio. This shows potential for creativity in the speaker embedding latent space to represent new voices. Second, we use cosine similarity to compare our diffusion acoustic model with a model based on DurIAN. We find that the latter has better conversion results, fewer parameters, and less training time. Overall, we conclude that cosine similarity is a helpful objective metric for voice morphing and conversion.
An electroglottographic study on the effect of following context on glottal constriction in Australian English coda /t/
Authors: Ratko Louise , Penney Joshua , Cox Felicity
Published: November 2023

To achieve inhibition of voicing for voiceless speech sounds, the glottis may be either spread or constricted. Glottal spreading may lead to breathiness, and constriction to glottalization. Previous research has shown that glottalization associated with English coda /t/ differs as a function of surrounding environment, with glottalization more likely when the following word begins with a sonorant consonant (such as /l, n/) compared to other environments. However, it is unclear the extent to which following sonorant consonants induce glottalization compared to following vowels. We used an electroglottograph to record 12 Australian English speakers producing phrases eliciting coda /t/ in target words preceding words with onset sonorants /n, l/ (now, long) and onset vowels /əʉ, ə/ (only, again). Open quotient (OQ) was established through the second half of the target word vowel. Increasing OQ indicates breathiness whereas lowering OQ indicates constriction. Using generalized additive mixed modelling we found that the OQ of vowels preceding coda /t/ in the sonorant-following context was significantly lower than in vowel-following contexts. This indicates greater glottal constriction when a sonorant consonant follows the coda /t/, showing that coda /t/ voicelessness is implemented differently before sonorant consonants compared to vowels
Robustness of lateral tongue bracing in second language speech
Authors: Bengtson Grace , Moniz Amanda , Samarskaya Maria , Liu Yadong , Gick Bryan
Published: November 2023

Lateral tongue bracing, a universal speech posture, is an actively maintained robust position, akin to standing and locomotion [Gick et al., 2017, JSLHR 60; Liu et al., 2022, JIPA, Phonetica 79]. Studying the robustness of bracing in second-language (L2) speakers can provide insight into learning of speech posture. In this study, we investigate the extent to which speaking in a second language affects the robustness of lateral tongue bracing compared to first language (L1) speech. Participants read two short texts, one in their native language and one in their second language, under a 10 mm bite-block condition. Intra-oral videos are analyzed for the percentage of time bracing occurred in continuous speech. Our preliminary results showed a decrease in the overall percentage of lateral contact during L2 continuous speech compared to L1. These insights invite a reassessment of our existing parallel posture model. We suggest adapting this model to account for the cognitive demands of L2, and the possible role of learning language-specific articulatory settings in postural robustness for L2 speakers.
Multipath time delay estimation based on the improved Wigner-ville distribution
Authors: Zou Yifei , Li Xiukun , YU Ge
Published: November 2023

The accuracy of underwater multipath channel time delay is crucial in underwater acoustic signal processing. The temporal resolution of the traditional matched filter is restricted by the transmitted signal bandwidth. Wigner-Ville distribution (WVD) which has excellent energy concentration characteristics and effectively avoids the interaction between temporal and frequency resolutions, and is widely used in non-stationary signal processing. However, considering the multipath signal processing, the cross-term in echo WVD would cause inaccurate time delay estimation. Therefore, in this paper, a novel multipath signal time delay estimation method based on the improved WVD is proposed. By utilizing the difference in the continuity of energy changes between auto-term and cross-term in the time-frequency domain, the Seeded Region Growing algorithm is applied and improved to extract auto-term in the WVD. The simulation results show that the method removes cross-term and maintains high concentration characteristics of auto-term, compared with pseudo-WVD and smooth pseudo-WVD, etc. In addition, it improves the accuracy of multipath signal delay estimation and has some anti-noise ability.
Lessons learned from time reversal communications
Authors: Song Heechun
Published: November 2023

Time reversal (TR) is a technique that utilizes spatial diversity to achieve spatial and temporal focusing in complex environments. This approach has been successfully applied to phase-coherent acoustic communications in time-varying multipath environments, providing an alternative to conventional adaptive multichannel equalizers (M-DFE). Essentially, the TR method involves combining multichannels as a spatial precombiner, effectively reducing channel complexities and achieving optimal performance. This presentation will discuss the insights gained from using the TR approach for underwater communications under diverse underwater conditions.
R&D of a low-complexity acoustic communication payload for small-size AUV
Authors: Tong feng , Qiu yifang , hao shuaifeng , Zhang Fumin
Published: November 2023

Due to its features of low-cost, deployment-convenience and low detection probability, small size AUV is drawing more and more attention from diverse marine fields. While the technique of acoustic communication is capable of enabling wireless link of small size AUV, difficulties caused by adverse underwater acoustic mobile channel such as multipath, Doppler and noise pose significant challenges. Moreover, extremely strict constaints in terms of size, power supply and real-time caculation capability means that R&D of acoustic communication payload need to seek a tradeoff between the algorithm performance and system overhead. To deal with the abovementioned hurdles, a lightweight acoustic communication payload for small-size AUV is designed. Specifically, the proposed payload adopts symbol-wise low-complexity Doppler estimation and compenstaion process, which is incorporated with a compact channel equalizer to achieve reliable mobile communication under Doppler and multipath conditions. The hardware and software design associated with the efficient system implementation of the proposed scheme is given. Finally, lake trial results performed based on small size AUV equiped with the proposed acoustic communication payload is presented to verify its effectiveness.
Robust Doppler compensation for low frequency underwater communications
Authors: Sung Chang , Cooper Patrick , La Mela Daniel , Cain Tim
Published: November 2023

Impairment caused by Doppler frequency shift and harsh channel condition distinguish underwater acoustic communications from radio communications. Slow speed of acoustic waves produces relatively high Doppler shift and result in expansion or compression in time samples, which is known as Doppler scaling. In particular, the Doppler scaling causes significant carrier frequency offset (CFO) in orthogonal frequency division modulation (OFDM). To compensate the CFO, it is essential to resample signal samples according to the Doppler scale. In theory, the Doppler scale can be estimated by measuring the distance between peaks of the matched filter output of consecutive Doppler-invariant preambles. In practice, multi-path reflections and non-orthogonality between the HFM and OFDM payload produce large numbers of local false peaks. In this paper, we propose a robust Doppler estimation technique by employing constant false alarm rate (CFAR) filter to remove false peaks. We validate the performance of the proposed scheme through two sea-trials carried out in shallow water near Jervis Bay, Australia. In the sea-trials, a slow-moving towed hydrophone array was deployed as the receiver and the source was a stationary, low source level, vertical transmit array. Sea-trial results demonstrated up to 112bps information rate using bit-interleaved coded OFDM over 400 Hz bandwidth.
The complexity of harmonically scattered nonlinear waves from triangular, circular, and rectangular corners of the 2-D domain
Authors: Ghodake Pravinkumar
Published: November 2023

Considering recent advancements in the nonlinear pulse-echo technique, understanding reflected nonlinear waves from inaccessible edges and surfaces becomes important. A unique geometrical model solved numerically using the finite element method is proposed and studied via extensive numerical experiments to gain insight into harmonically scattered waves from different shapes of the 2-D spaced corners considering the challenges of theoretical solutions that can capture the interplay between multiple phenomena. Tang et al. (2012), Kube (2017-18), and Achenbach and Wang (2017-18) studied the harmonic scattering of waves from nonlinear inclusions using analytical techniques. Linear longitudinal waves scattered from the triangular, circular, and rectangular-shaped free and fixed edges of the 2-D spaced corner show mode conversion and energy transfer between bulk wave modes at fundamental frequencies. The interaction of nonlinear ultrasonic waves with the edges makes things complex due to an interplay between harmonic generation, linear scattering, harmonic scattering, bulk wave mode conversion, and harmonic energy redistribution between all harmonics of the scattered longitudinal and transverse waves. This results in non-intuitive interesting responses. These studies are extended to explore one-way and two-way two-wave mixing of longitudinal waves and their interesting nonlinear effects. Phase difference introduced during harmonic scattering distinguishes the sensitivity of fundamental harmonics.
Discrete element models for elasto-plastic wave propagation in nonlinear architected materials
Authors: Wallen Samuel P. , Haberman Michael , DeLima Washington
Published: November 2023

Nonlinear architected materials are known to exhibit a plethora of dynamic phenomena that enhance our capacity to manipulate elastic waves. Since these properties stem from complex, subwavelength geometry, dynamic simulations at high resolutions are often intractable at scales of interest. Therefore, prior studies have turned to effective medium models that capture essential properties in the long-wavelength limit. One class of such models is a periodic structure composed of discrete mass, spring, and damper elements, whose constitutive relationships are computed to match behaviors observed in experiments or fine-scale simulations of representative volume elements. While models of this type have been implemented successfully in many cases, the majority of literature has been focused on recoverable deformation, possibly including linear damping. However, history-dependent effects, such as friction and plasticity, have been much less explored. In this work, we develop a discrete element modeling framework for nonlinear architected materials undergoing plastic deformation. Due to the history- and rate-dependent characteristics of plasticity, the framework generally yields a system of differential-algebraic equations whose computational cost is significantly greater than an elastic system of comparable size. We demonstrate the method using several examples from the literature and explore means to obtain phenomenological plasticity models for general geometries.
Theory for highly stressed thick-walled elastic spheres and their vibration without small strain approximations
Authors: McMahon Darryl
Published: November 2023

This paper considers how the radii and vibration of an elastic thick-walled sphere is affected by high stresses imposed by high external pressures or by high internal pressures. For simplicity, the sphere consists of idealized Hookean material allowing unlimited compression or expansion. The sphere is filled by material with an isotropic pressure that generally differs from the pressure on the outer surface of the sphere. The analysis includes large strain nonlinear curvature effects where, unlike linear elasticity theory, the difference in radial and tangential strains is not small compared to those strains. Despite the sphere’s robustness, destructive physical consequences are predicted for nonzero Poisson coefficients where, for instance, a high-pressure tank inner stresses make the inner radius approach the less stressed outer radius. This would be avoided if the Poisson coefficient changed with large strains and approached zero. To model the effect of high stresses and strains on breathing mode vibration, an effective spring constant is derived from quadratic radius deviations of the system potential energy from equilibrium. Insights from analysis avoiding linear elasticity approximations may be applicable to improved understanding of deep-sea marine creature survival, improved underwater vessel design for large depths, and safer containers of fluids at high pressures.
Interactions between attention and auditory scene analysis
Authors: Shinn-Cunningham Barbara
Published: November 2023

Do auditory objects form automatically, or only when a listener focuses attention on a sound? This review argues that the question is ill posed—that both are simultaneously correct. Intuition suggests that the processes of source segregation and attention happen sequentially: first segregation parses a complex scene into constituent objects, and then selection pulls out an important sound to be analyzed in detail. But, rather than a processing hierarchy in which object formation occurs first, followed by selection, auditory scene analysis and attention interact in a heterarchy: formation and selection influence one another, feed back upon each other, and are not easily separable in terms of either how they are implemented in the brain or how their effects can be measured. There is not one particular site in the auditory pathway where objects “first appear;” instead, an object-based representation emerges gradually and imperfectly from the auditory nerve through the brainstem and midbrain to the various divisions of the cortex. Similarly, attentional selection accrues at every stage as one moves from the ear to the cortex. This talk will review examples from perceptual and physiological experiments supporting the idea that attention and object formation interact heterarchical.
Naturalistic behaviors for studying object identification in auditory cortex
Authors: Ferreiro Dardo N. , Amaro Diana , Grothe Benedikt , Pecka Michael
Published: November 2023

Localizing and identifying sensory objects while exploring the environment are fundamental brain functions. Yet despite decades of study, we still do not fully understand how auditory cortex neurons represent sound locations, or how those representations are affected by context and behavior. In particular, little is known about brain function when sensory inputs are processed during active sensing. Here, we present results of gerbils, freely moving, performing the Sensory Island Task (SIT). In SIT, animals are free to forage for a specific spot (the island) in the experimental arena which, upon being found, triggers a change in the auditory stimulation location; which animals report by staying within the island for an extended time period, in order to receive a reward. By coupling one of the sound sources to reward delivery, we demonstrate that sound source identity shapes single cell spatial preference in the primary auditory cortex during active navigation. We further showcase other implementations of SIT which enable the study of the neural processes and behaviors underlying active perception in ethologically relevant scenes.
When and where to listen?
Authors: Encke Joerg , McAlpine David
Published: November 2023

In natural listening environments, humans hear multiple concurrent sounds arriving from different locations. In order to attend to a single source, concurrent sounds must be separated into individual sound objects, a process that relies on binaural hearing. However, the fluctuating binaural cues that arise when sounds from multiple sources merge at each ear generate fluctuating binaural cues that may be unreliable as to source location. This reliability can be quantified in terms of the interaural coherence (IAC). To overcome unreliable binaural cues, it is suggested that the brain monitors IAC and extracts spatial information from sound energy during epochs where IAC is high. To test this hypothesis, we designed a stimulus allowing us to modulate IAC over time and frequency. Our data indicate that IAC weighting plays a relatively minor role in source separation. Rather, binaural cues only contribute to source localization during rising sound energy. Binaural cues in later epochs of a modulated sound waveform are completely ignored even when IAC is high and spans a wide frequency range. The data do not support weighting based on IAC but, rather, suggest a fast, “non-sluggish” processing of binaural cues to extract information only during the rising energy envelope.
Model for underwater noise due to bubble clouds and comparison with observations from Monterey accelerated research system observatory
Authors: Raju Ranga P. , Chandrayadula Tarun K.
Published: November 2023

Empirical models for underwater noise spectrum from bubbles suggest a general increase by 5 dB for every doubling of wind speed. However, at wind speeds greater than 10 m/s and frequencies higher than 10 kHz, observations report a decrease in noise with increase in wind. This is due to the formation of bubble clouds, which radiate sound, but also attenuate the intensities because of the air contained within them. The bubble clouds occur in certain shapes called α, β, and γ plumes, which evolve during the various stages of wave-breaking. There are yet no quantitative underwater noise models that combine the nature of these clouds, with their acoustics. This paper builds the model in two steps. First, inputs such as wind speed and wave height are used to approximate the clouds as spheres, with respective number of bubbles of each radius and mean spacing between the clouds. Second, this approximate model is then used to predict the radiated sound. To test the model, predictions are setup for comparison with measured noise during high winds around Monterey, California. To input relevant environment parameters to the model, the work uses measurements of wind-velocities, and wave-heights, measured on-site. For acoustic recordings, the work uses hydrophone from the Monterey Accelerated Research System (MARS) cabled observatory.
Auralization as a tool for design and subjective analysis
Authors: Jaramillo Ana M. , Basso Gustavo , Olson Bruce C.
Published: November 2023

During the remodel of Teatro Colon in Argentina in the period 2006/2010, acousticians performed acoustic measurements at ten different stages of deconstruction and then repeated them during construction. Each stage allowed them to verify that the internationally renowned acoustic quality of the venue was not going to be lost with the use of new materials, especially the new upholstery of the seating. This study re-creates some of those stages using EASE acoustic modeling software, explores how auralizations of a model compare to auralizations of measured IRs, and how this type of prediction can be used as a design tool.