Acoustic Trace Research Articles

Experimental Testing of Acoustic Thermometry at the Scale of the Sea of Japan with a Receiver System Placed on the Axis of an Underwater Sound Channel

We discuss the results obtained when performing a test acoustic-hydrological experiment in August 2022 at a marine test site from the coast of Sakhalin Island to Kita-Yamato Bank in the Sea of Japan. The methodology of preliminary studies in the water area intended for studying climatic variability of temperature regimes of the aquatic environment based on numerical modeling using the RAY computational program and the NEMO ocean hydrodynamic circulation model is presented. One of the main results is the average temperature of the marine environment calculated with high accuracy on the axis of the underwater sound channel in the Sea of Japan on the 1000-kilometer acoustic trace at the crossing of the vortex system. The shape of the measuring system and the technical and computational means and methods described in the article can be used as a basis for the organization of high-precision operational monitoring of thermodynamic processes in extended sea areas.

Speech-Driven Spectrotemporal Receptive Fields Beyond the Auditory Cortex

We recently developed a method to estimate speech-driven spectrotemporal receptive fields (STRFs) using fMRI. The method uses spectrotemporal modulation filtering, a form of acoustic distortion that renders speech sometimes intelligible and sometimes unintelligible. Using this method, we found significant STRF responses only in classic auditory regions throughout the superior temporal lobes. However, our analysis was not optimized to detect small clusters of STRFs as might be expected in non-auditory regions. Here, we re-analyze our data using a more sensitive multivariate statistical test for cross-subject alignment of STRFs, and we identify STRF responses in non-auditory regions including the left dorsal premotor cortex (dPM), left inferior frontal gyrus (IFG), and bilateral calcarine sulcus (calcS). All three regions responded more to intelligible than unintelligible speech, but left dPM and calcS responded significantly to vocal pitch and demonstrated strong functional connectivity with early auditory regions. Left dPM's STRF generated the best predictions of activation on trials rated as unintelligible by listeners, a hallmark auditory profile. IFG, on the other hand, responded almost exclusively to intelligible speech and was functionally connected with classic speech-language regions in the superior temporal sulcus and middle temporal gyrus. IFG's STRF was also (weakly) able to predict activation on unintelligible trials, suggesting the presence of a partial ‘acoustic trace’ in the region. We conclude that left dPM is part of the human dorsal laryngeal motor cortex, a region previously shown to be capable of operating in an ‘auditory mode’ to encode vocal pitch. Further, given previous observations that IFG is involved in syntactic working memory and/or processing of linear order, we conclude that IFG is part of a higher-order speech circuit that exerts a top-down influence on processing of speech acoustics. Finally, because calcS is modulated by emotion, we speculate that changes in the quality of vocal pitch may have contributed to its response.

Sound transmission of acoustic metamaterial beams with periodic inertial amplification mechanisms

This paper presents the improved sound insulation performance obtained from a new type of acoustic metamaterial, built by attaching periodic inertial amplification (IA) mechanisms to a host beam. The IA mechanism is a triangular bar-and-hinge device, which connects a small mass to the host beam at two separate locations. The band structure of a unit-cell and the Sound Transmission Loss (STL) of a finite-length beam are calculated by the spectral element method (SEM), which are validated against finite element references. Numerical simulations show that the STL of the IA acoustic metamaterial beam outperforms that of an ordinary beam across a wide band starting from a very low frequency, which suggests the low-frequency soundproof capacity of the IA acoustic metamaterial beam is greatly enhanced. However, the STL curve also experiences a sudden fall after that band, causing an undesired sound insulation valley. To reveal the underlying physics, the band diagram of the beam is studied together with the trace wavenumber of the incident sound wave. It is found that, due to the collectively amplified inertia of periodic small masses, a wide bandgap is introduced in the band diagram at low frequencies, which effectively suppresses flexural vibration of the beam and eventually leads to the observed STL enhancements. However, as a consequence of this bandgap, band diagram inevitably intersects with acoustic trace wavenumber, creating a coincidence phenomenon. Although happens earlier than classical coincidence, this new coincidence produces a similar STL valley. To mitigate this drawback, a hybrid unit-cell containing two IA mechanisms is designed, which attempts to cover the valley caused by one mechanism with the bandgap induced by the other. The effectiveness of this new design is verified and discussed at last.

I-BEAT: Ultrasonic method for online measurement of the energy distribution of a single ion bunch

The shape of a wave carries all information about the spatial and temporal structure of its source, given that the medium and its properties are known. Most modern imaging methods seek to utilize this nature of waves originating from Huygens’ principle. We discuss the retrieval of the complete kinetic energy distribution from the acoustic trace that is recorded when a short ion bunch deposits its energy in water. This novel method, which we refer to as Ion-Bunch Energy Acoustic Tracing (I-BEAT), is a refinement of the ionoacoustic approach. With its capability of completely monitoring a single, focused proton bunch with prompt readout and high repetition rate, I-BEAT is a promising approach to meet future requirements of experiments and applications in the field of laser-based ion acceleration. We demonstrate its functionality at two laser-driven ion sources for quantitative online determination of the kinetic energy distribution in the focus of single proton bunches.

A Contextual GMM-HMM Smart Fiber Optic Surveillance System for Pipeline Integrity Threat Detection

This paper presents a novel pipeline integrity surveillance system aimed to the detection and classification of threats in the vicinity of a long gas pipeline. The sensing system is based on phase-sensitive optical time domain reflectometry (φ-OTDR) technology for signal acquisition and pattern recognition strategies for threat identification. The proposal incorporates contextual information at the feature level in a Gaussian Mixture Model and Hidden Markov Model (GMM-HMM) based pattern classification system and applies a system combination strategy for acoustic trace decision. System combination relies on majority voting of the decisions given by the individual contextual information sources and the number of states used for HMM modeling. The system runs in two different modes: first, machine+activity identification, which recognizes the activity being carried out by a certain machine, second, threat detection, aimed to detect threats no matter what the real activity being conducted is. In comparison with the previous systems based on the same rigorous experimental setup, the results show that the system combination from the contextual feature information and the GMM-HMM approach improves the results for both machine+activity identification (7.6% of relative improvement with respect to the best published result in the literature on this task) and threat detection (26.6% of relative improvement in the false alarm rate with 2.1% relative reduction in the threat detection rate).

The response of an acoustic trace wavelength enhanced array to an isotropic noise field and optimum processing

Recently, a new array based on generating Bragg-scattered acoustic wavelengths along the surface of an array was proposed (Enhanced directivity with array grating (J. Acoust. Soc. Am. 136 (2), 2014) and Experimental verification of acoustic trace wavelength enhancement (J. Acoust. Soc. Am. 138 (6), 2015)). The technique, denoted acoustic trace wavelength enhancement, relies on embedding periodic structures within an array, chosen to precisely replicate and shift the incident acoustic wavenumber into higher wavenumber regions. In principle, an important advantage of this array over conventional hydrophone-based arrays of the same size is its greatly improved directivity. A prototype array was built and demonstrated in a test tank under idealized high signal-to-noise ratio conditions. However, two important open questions which remain are how this array responds to ambient noise and how to optimally beamform it when multiple signals are present. Using idealized analytical models for the array's plane wave r...

Achievable performance of a novel Bragg-scattered acoustic receiving array

The merits of a novel beamforming technique, based on generating Bragg-scattered acoustic wavelengths along the surface of an array, will be described. The technique, denoted acoustic trace wavelength enhancement, relies on embedding periodic structures within an array, chosen to precisely replicate and shift an incident acoustic wavenumber into higher wavenumber regions. Thus, shorter trace wavelengths are created over the aperture surface. The enhancement technique is documented in two recent publications: enhanced directivity with array grating [J. Acoust. Soc. Am. 136, 2014] and experimental verification of acoustic trace wavelength enhancement [J. Acoust. Soc. Am. 138, 2015). These references dealt, however, solely with high signal-to-noise ratios. Specifically, we will investigate the noise characteristics of this new array by calculating its array gain and Cramer-Rao lower bounds on bearing estimation error for plane wave signals embedded in an isotropic Gaussian noise field. Of particular interest...

Dynamic microplasticity manifestation in consolidated sandstone in the acoustical frequency range

ABSTRACTMicroplasticity manifestations caused by acoustic wave in the frequency range of about 4.5 kHz–7.0 kHz are detected in consolidated artificial sandstone. Equipment was tested by means of comparison of data obtained for a standard material (aluminium) and sandstone. Microplasticity manifestations in acoustic records are present in the form of ladder‐like changes in the amplitude course. The stress plateaus in the acoustic trace interrupt the amplitude course, transform the wavefront, and shift the arrival time along the time axis. Microplasticity contribution to the acoustic record changes with the increase in the strain amplitude value. The combined elastic–microplastic process conditions the wavefront steepness and its duration. Stress plateaus exert influence on the waveform and, accordingly, on pulse frequency response. These results confirm the earlier data obtained for weakly consolidated rock. This contribution to wave propagation physics can be useful in solving applied problems in material science, seismic prospecting, diagnostics, etc.

Phonetic basis of phonemic paraphasias in aphasia: Evidence for cascading activation

Phonemic paraphasias are a common presenting symptom in aphasia and are thought to reflect a deficit in which selecting an incorrect phonemic segment results in the clear-cut substitution of one phonemic segment for another. The current study re-examines the basis of these paraphasias. Seven left hemisphere-damaged aphasics with a range of left hemisphere lesions and clinical diagnoses including Broca's, Conduction, and Wernicke's aphasia, were asked to produce syllable-initial voiced and voiceless fricative consonants, [z] and [s], in CV syllables followed by one of five vowels [i e a o u] in isolation and in a carrier phrase. Acoustic analyses were conducted focusing on two acoustic parameters signaling voicing in fricative consonants: duration and amplitude properties of the fricative noise. Results show that for all participants, regardless of clinical diagnosis or lesion site, phonemic paraphasias leave an acoustic trace of the original target in the error production. These findings challenge the view that phonemic paraphasias arise from a mis-selection of phonemic units followed by its correct implementation, as traditionally proposed. Rather, they appear to derive from a common mechanism with speech errors reflecting the co-activation of a target and competitor resulting in speech output that has some phonetic properties of both segments.

Experimental verification of acoustic trace wavelength enhancement.

Directivity is essentially a measure of a sonar array's beamwidth that can be obtained in a spherically isotropic ambient noise field; narrow array mainbeam widths are more directive than broader mainbeam widths. For common sonar systems, the directivity factor (or directivity index) is directly proportional to the ratio of an incident acoustic trace wavelength to the sonar array's physical length (which is always constrained). Increasing this ratio, by creating additional trace wavelengths for a fixed array length, will increase array directivity. Embedding periodic structures within an array generates Bragg scattering of the incident acoustic plane wave along the array's surface. The Bragg scattered propagating waves are shifted in a precise manner and create shorter wavelength replicas of the original acoustic trace wavelength. These replicated trace wavelengths (which contain identical signal arrival information) increase an array's wavelength to length ratio and thus directivity. Therefore, a smaller array, in theory, can have the equivalent directivity of a much larger array. Measurements completed in January 2015 at the Naval Undersea Warfare Center's Acoustic Test Facility, in Newport, RI, verified, near perfectly, these replicated, shorter, trace wavelengths.

Enhanced directivity with array gratings.

A planewave, incident on a panel, produces an acoustic trace wavelength that propagates along the surface of the panel. The trace wavelength excites the panel into vibration, creating structural waves within the panel that propagate. These structural waves can be purposely Bragg scattered, creating replicas of the trace wavenumber. The replicas are shifted in wavenumber precisely by the inverse of the periodic separation distance l. Hence, in principle, it should be possible to resolve the acoustic trace wavelength from one of the shifted replicas of the panel's response. The incident angle can then be ascertained from the replicated trace wavelengths.

Were we or are we? Perception of reduced function words in spontaneous conversations.

Spontaneous, reduced pronunciations diverge greatly from citation forms. The quality of a single segment can change, e.g., /b/ in “about” surfacing as an approximant. But sounds, syllables, and entire words can also be deleted (e.g., “do you have time?” as [djutEm] with no acoustic trace of “have”). This work investigates the perception of reduced function words such as “he was” or “we were.” Twenty-two young American English speakers’ spontaneous conversations with close acquaintances were recorded. From these, we selected utterances containing items such as “he’s/he was, we’re/we were, got him/got them.” When hearing an entire utterance, native listeners may clearly perceive “we were,” but on hearing just the “we were” portion, they perceive an unambiguous “we’re.” The portion of the signal presented to listeners is manipulated to determine the contributions of local acoustic cues, speech rate and coarticulation, semantic and syntactic information, and overall bias toward present vs past tense. An auditory and a written task are also compared to separate the contribution of intonation from that of syntax/semantics. These results begin to elucidate the interplay of information sources listeners draw upon when parsing spontaneous speech. Future work will compare to non-native listeners’ perceptions.

Poor scaling between elastic energy release and eruption intensity at Tungurahua Volcano, Ecuador

An important objective in volcanology is the quantification of eruption intensity through the study of elastic energy propagated into the atmosphere and ground. To better understand the relation between elastic wave radiation and eruptive activity we deployed seismic, acoustic, and video instrumentation at the active Tungurahua Volcano (Ecuador) in Nov.–Dec. of 2004. Our data show that plume expansion scales very poorly with both seismic and acoustic trace energy and only the initial amplitude of the acoustic signal is perhaps correlated with initial plume rise speeds. In general, the eventual size of Tungurahua eruption plumes does not appear to be controlled by elevated material accelerations within the conduit, which are primary influences on elastic energy radiation. This result has vital implications for volcano observatories, which are interested in using seismic and acoustic trace amplitudes as proxies for eruption magnitudes.

Similarities in weak syllable omissions between children with specific language impairment and normally developing language: a preliminary report

Two-year-olds with normally developing language (NL) and older children with specific language impairment (SLI) omit initial weak syllables from words (e.g., “ banana”∼“ nana” ). Previous research revealed a phonetic “trace” of syllables omitted by children with NL ( Carter, 1999; Carter & Gerken, submitted for publication). The present study asked whether similar evidence could be found for omissions by children with SLI. Fourteen children with SLI produced sentences containing reduced or unreduced disyllabic proper names (e.g., “Feed_cinda,” from “Feed Lucinda” vs. “Feed Cindy”). Acoustic analyses revealed a significantly longer duration for verb-onset to name-onset of sentences containing the reduced name, indicating that although segmental material is omitted, an acoustic trace remains. In addition, a phonological examination showed similarities between groups regarding sentential and syllabic factors that affect omission rates, as well as an interesting difference that suggests different strategies the groups use in acquiring adult targets. Learning outcomes As a result of reading this article, participants should (1) have a better understanding of similarities and differences in the language production of children with specific language impairment and normally developing language, with regard to prosodic development, (2) be familiar with several models of the phenomenon of weak syllable omissions in children’s developing language, and (3) recognize the importance of using a combination of linguistic analysis types when studying issues in child language production.

The multiple source feedback of supersonic jet screech, III: Space-time diagrams applied to the helical mode

The foregoing feedback theory applies directly to the sinuous and toroidal instability modes of supersonic jets, but needs modification for the helical C mode since the acoustic feedback to the nozzle must at the axial trace velocity of the resultant helical sound field (Powell, Umeda, and Ishii, 1990). Here the space-time diagram is equivalent to an instantaneous map of the positions of the helical instability and acoustic wave on the cylindrical bounding surface of the jet, one period being replaced by one circumference. The instantaneous space-time (sound) pressure measurements of Westley and Woolley (1975) are interpreted in this way. The acoustic feedback trace velocity is found to be approximately sonic. The circumferential velocity (=πf×diameter source orbit diameter), in a plane normal to the jet axis is inferred to be supersonic. The phase velocity of the helical wave along the curved surface is then found to be subsonic rather than sonic as originally assumed in the tentative theory. A simple numerical simulation (including the reflection from the flange) reproduces the main features of the complex map of instantaneous pressure, including the prominent standing waves.

Horizontal refraction and sound fluctuations caused by internal waves packets in shallow water

The subject of the paper is to consider the propagation of a low-frequency sound field in shallow water in the presence of solitonlike internal waves (SLIW). It is assumed that SLIW spread approximately across the stationary acoustic trace. The problem of sound propagation is considered within the framework of 3-D model of the shallow water. The theory of ‘‘horizontal rays and vertical modes’’ is applied to take into account influence of horizontal refraction due to SLIW. As shown in the paper SLIW can lead (periodically in time) to ‘‘focusing’’ and ‘‘defocusing’’ of the horizontal rays or, in other words, to the periodic appearance of ‘‘horizontal waveguide.’’ Estimations of the sound fluctuations due to SLIW demonstrate that the amplitude of fluctuations can reach up to 10–20 dB (between moments of the ‘‘focusing’’ and ‘‘defocusing’’). The next effect conditioned by internal waves is horizontal filtering of vertical modes, where we have separate focusing and defocusing rays, corresponding to different vertical modes at different points of horizontal waveguide. The results presented in the paper can be used as the basis of remote sensing of the internal waves packets in shallow water. [Work supported by RFBR, Grant 97-05-64878.]

Two true surface acoustic waves and other acoustic modes in (110) plane of Li2B4O7 substrate

The surface acoustic waves (SAWs) and other acoustic modes propagating in the (110) plane of Li2B4O7 are investigated by means of the effective surface permittivity (ESP). It is demonstrated that the velocity of all piezoactive SAWs, both true and pseudo, as well as surface skimming bulk waves (SSBWs) can be numerically determined by computing the ESP as a function of acoustic trace slowness. A physical phenomenon not reported has been found for certain propagation directions, namely, simultaneous existence of two true SAWs, both being of the generalized Rayleigh type, together with a pseudo SAW of similar polarization. Propagation velocity, electromechanical coupling coefficient, and decay factor have been verified and confirmed by using two different sets of material constants and two numerical methods. The obtained values and accuracy of SAWs parameters are compared, and the validity conditions discussed. The generalized slowness diagram, plotted for the sagittal plane, enables to determine the total number of SSBW and to interpret the depth penetration properties of SAW. The Nyquist diagram of the ESP is shown to be a more helpful form for identifying a pseudo SAW and for distinguishing it from a SSBW.

Acoustic rhinometry: an explanation of some common artefacts associated with nasal decongestion.

The nasal cavities of 51 healthy volunteers were examined using acoustic rhinometry before and after nasal decongestant. Several specific dimensions were studied, which included the minimum cross-sectional area, and three volumes corresponding to the anterior, middle and posterior regions of the nasal airway. An average acoustic rhinometry trace was constructed for the whole group of subjects, before and after decongestion, from data extracted from the raw data files written to the computer hard disk for each subject. A 27.5% (P < 0.0001) increase in the minimum cross-sectional area was observed, with no shift in its position. The greatest increase in nasal dimensions was seen in the anterior and middle parts of the nose, however, significant changes were also seen in the posterior nasal cavity and post nasal space. There are a number of possible sources of artefact. First, confusion of the first and second minima may produce apparent movement of the minimum cross-sectional area following nasal decongestion. Second, a postulated change in the acoustic path length may lead to apparent changes in volume in certain regions of the nose. Third, a variable and uncontrollable degree of sound energy loss will occur into the opposite nasal cavity beyond the posterior border of the septum. An apparent increase in the dimensions of this region will be seen as the opposite cavity decongests. We feel that all users of the acoustic rhinometer need to be aware of these potential sources of artefact, and attention needs to be focused on an agreed definition of the components of the acoustic rhinometry trace.

A sensory-enhanced context facilitates learning and multiple measures of unconditioned stimulus processing in the preweanling rat.

This study tested the hypothesis that increased processing or efficacy of the unconditioned stimulus (US) contributes to the facilitation of trace conditioning that occurs when preweanling rats are conditioned in a novel sensory-rich context. Experiment 1 extended previous findings (D. L. McKinzie & N. E. Spear, 1995) of facilitated acoustic trace conditioning in the 17-day-old rat in a sensory-enhanced versus a home odor context. In the enhanced or more familiar context, Experiment 2 tested rats of this age for degree of spontaneous locomotor activity and ultrasonic vocalizations, activity and ultrasounding in response to shock, and the acoustic startle reflex. The enhanced context resulted in a greater overall activity response to shock, increased ultrasounding to discrete shocks, and a sensitized latency to startle. The results suggest that enhanced US processing in a sensory-rich context is a likely contributor to its facilitative effect on infant learning.

Acoustic rhinometry: do we need a standardized operating procedure?

The usefulness of a standardized operating procedure for acoustic rhinometry was assessed in a study on 51 healthy volunteers. Nasal measurements were made with acoustic rhinometry before and after application of a topical nasal decongestant. Our standard operating procedure used three consecutive readings of anterior nasal volume to obtain a valid estimate of mean nasal dimensions. The mean measurement was only accepted as valid if the three readings had a coefficient of variation (CV) of less than 20%. Twenty-two out of 192 (11.5%) nasal cavities required more than three consecutive readings to achieve this. Our data show that the error encountered by relying on a single reading of an acoustic trace can be greater than the changes caused by the topical nasal decongestant and that multiple readings using a standard operating procedure are essential to obtain valid data.