Acoustic Manifestations Research Articles

Effects of viscous dissipation in propagation of sound in periodic layered structures

Propagation and attenuation of sound through a layered phononic crystal with viscous constituents is theoretically studied. The Navier–Stokes equation with appropriate boundary conditions is solved and the dispersion relation for sound is obtained for a periodic layered heterogeneous structure where at least one of the constituents is a viscous fluid. Simplified dispersion equations are obtained when the other component of the unit is either elastic solid, viscous fluid, or ideal fluid. The limit of low frequencies when periodic structure homogenizes and the frequencies close to the band edge when propagating Bloch wave becomes a standing wave are considered and enhanced viscous dissipation is calculated. Angular dependence of the attenuation coefficient is analyzed. It is shown that transition from dissipation in the bulk to dissipation in a narrow boundary layer occurs in the region of angles close to normal incidence. Enormously high dissipation is predicted for solid–fluid structure in the region of angles where transmission practically vanishes due to appearance of so-called “transmission zeros,” according to El Hassouani, El Boudouti, Djafari-Rouhani, and Aynaou [Phys. Rev. B 78, 174306 (2008)]. For the case when the unit cell contains a narrow layer of high viscosity fluid, the anomaly related to acoustic manifestation of Borrmann effect is explained.

Precision medicine in ALS: Identification of new acoustic markers for dysarthria severity assessment

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting motorneurons of the bulbar, cervical, thoracic, or lumbar segments. Bulbar presentation is a devastating characteristic that impairs patients’ ability to communicate and is linked to shorter survival. Early acoustic manifestation of voice symptoms, such as dysarthria, is very variable, making its detection and classification challenging, both by human specialists and automatic systems. In this context, precision medicine, defined as “prevention and treatment strategies that take individual variability into account”, has gained a great interest in the ALS community. Specifically, the use of innovative Artificial Intelligence techniques, such as Machine Learning, plays a pivotal role in finding specific patterns in the data set to help neurologists in clinical decision-making. Therefore, the main objective of this study was to find new markers, and new patterns, to promptly detect the possible presence of dysarthria and to correctly classify its severity. We have performed an acoustic analysis on different voice signals of various degrees of impairment acquired during outpatient visits at the ALS center of the “Federico II” University Hospital. From the collected signals, a new database containing different acoustic parameters was realized, on which several experiments were performed. The study led us to the discovery of markers that helped to develop a decision tree that separated healthy subjects from patients and, among patients, those with different severity of dysarthria. This model achieved good results in terms of dysarthria classification accuracy, 86.6%, which is excellent considering the small number of subjects in the data set.

Introducing the COVID-19 YouTube (COVYT) speech dataset featuring the same speakers with and without infection

More than two years after its outbreak, the COVID-19 pandemic continues to plague medical systems around the world, putting a strain on scarce resources, and claiming human lives. From the very beginning, various AI-based COVID-19 detection and monitoring tools have been pursued in an attempt to stem the tide of infections through timely diagnosis. In particular, computer audition has been suggested as a non-invasive, cost-efficient, and eco-friendly alternative for detecting COVID-19 infections through vocal sounds. However, like all AI methods, also computer audition is heavily dependent on the quantity and quality of available data, and large-scale COVID-19 sound datasets are difficult to acquire – amongst other reasons – due to the sensitive nature of such data. To that end, we introduce the COVYT dataset – a novel COVID-19 dataset collected from public sources containing more than 8 h of speech from 65 speakers. As compared to other existing COVID-19 sound datasets, the unique feature of the COVYT dataset is that it comprises both COVID-19 positive and negative samples from all 65 speakers. We additionally provide an overview acoustic analysis and modelling baselines using different partitioning strategies. We analyse the acoustic manifestation of COVID-19 on the basis of these perfectly speaker characteristic balanced ‘in-the-wild’ data using interpretable audio descriptors, and investigate several classification scenarios that shed light into proper partitioning strategies for a fair speech-based COVID-19 detection.

A Machine Learning Enhanced Approach for Automated Sunquake Detection in Acoustic Emission Maps

Sunquakes are seismic emissions visible on the solar surface, associated with some solar flares. Although discovered in 1998, they have only recently become a more commonly detected phenomenon. Despite the availability of several manual detection guidelines, to our knowledge, the astrophysical data produced for sunquakes is new to the field of machine learning. Detecting sunquakes is a daunting task for human operators, and this work aims to ease and, if possible, to improve their detection. Thus, we introduce a dataset constructed from acoustic egression-power maps of solar active regions obtained for Solar Cycles 23 and 24 using the holography method. We then present a pedagogical approach to the application of machine-learning representation methods for sunquake detection using autoencoders, contrastive learning, object detection and recurrent techniques, which we enhance by introducing several custom, domain-specific data augmentation transformations. We address the main challenges of the automated sunquake-detection task, namely the very high noise patterns in and outside the active region shadow and the extreme class imbalance given by the limited number of frames that present sunquake signatures. With our trained models, we find temporal and spatial locations of peculiar acoustic emission and qualitatively associate them to eruptive and high energy emission. While noting that these models are still in a prototype stage, and there is much room for improvement in metrics and bias levels, we hypothesize that their agreement on example use cases has the potential to enable detection of weak solar acoustic manifestations.

Three quarters of a century of phonetic research on common Danish stød

AbstractDespite many attempts, we do not yet know how to answer the question exhaustively and adequately: What is common Danish stød phonetically? Specifically, is there an underlying physiological constancy behind the considerable acoustic variability? And is there a common denominator to the different acoustic manifestations that might explain their perceptual equivalence? Systematic acoustic, physiological, and perceptual investigations of common Danish stød now span (a little more than) three quarters of a century. This is a review of that research, to determine what may be considered established phonetic facts about common Danish stød and the open questions that remain for future research.

Multimodal Echography in Clarifying The Structural Features and Boundaries of Soft Multimodal Echography in Clarifying The Structural Features and Boundaries of Soft Tissues Lipomas

Data of echography of 210 verified on the operation and in histological research lipomas, including 182 (86.7 %) encapsulated and 28 (13.3 %) diffuse. Four possible rims along the periphery of the formations have been identified. The morphological nature of these acoustic manifestations and the frequency of their occurrence have been determined. Elastography did not improve its differentiation by showing the boundaries of formations more clearly.

Acoustic properties of word and phrasal prominence in Uzbek

Based on a large-scale corpus of experimental data produced by 8 native speakers of Tashkent Uzbek, we assess the presence of canonical word-final stress in real words spoken in three dialogue types: without focus, with contrastive focus, and with new information focus on the target. The first context provides baseline information regarding the manifestation of stress, in the absence of additional focus properties. By comparing the latter two contexts with the former, we are also able to assess the acoustic manifestation of the two types of focus. The most noteworthy properties of the final syllable are its relatively long duration and sharp falling contour, potentially serving as the cues to lexical stress, and enhanced by both types of focus. Due to the word-final position of stress, however, the patterns we observe could also be consistent with boundary properties, a possibility we consider as well. In addition, we briefly compare the prosodic patterns we observe in Uzbek with similarly collected data in Turkish. We find that the prominence patterns in Uzbek, while not particularly strong, are nevertheless stronger than those in Turkish, and also exhibit crucial differences. Implications for Turkic prosody more generally are also suggested.

Classification of ALS patients based on acoustic analysis of sustained vowel phonations

Amyotrophic lateral sclerosis (ALS) is incurable neurological disorder with rapidly progressive course. Common early symptoms of ALS are difficulty in swallowing and speech. However, early acoustic manifestation of speech and voice symptoms is very variable, that making their detection very challenging, both by human specialists and automatic systems. This study presents an approach to voice assessment for automatic system that separates healthy people from patients with ALS. In particular, this work focus on analysing of sustain phonation of vowels /a/ and/i/ to perform automatic classification of ALS patients. A wide range of acoustic features such as MFCC, formants, jitter, shimmer, vibrato, PPE, GNE, HNR, etc. were analysed. We also proposed a new set of acoustic features for characterizing harmonic structure of the vowels. Calculation of these features is based on pitch synchronized voice analysis. A linear discriminant analysis (LDA) was used to classify the phonation produced by patients with ALS and those by healthy individuals. Several algorithms of feature selection were tested to find optimal feature subset for LDA model. The study’s experiments show that the most successful LDA model based on 32 features picked out by LASSO feature selection algorithm attains 99.7% accuracy with 99.3% sensitivity and 99.9% specificity. Among the classifiers with a small number of features, we can highlight LDA model with 5 features, which has 89.0% accuracy (87.5% sensitivity and 90.4% specificity).

Landscape influence on biophony in an urban environment in the European Alps

ContextBiophony is the acoustic manifestation of biodiversity, and humans interact with biophony in many ways. However, quantifying biophony across urban landscapes has proven difficult in the presence of anthrophony, or sounds generated by humans. Improved assessment methods are required to progress our understanding of the processes influencing biophony across a variety of spatial–temporal scales.ObjectivesWe aimed to identify how the landscape influences biophony, as well as the total acoustic environment, along an urban to rural gradient. We designed the study to quantify how soundscape–landscape relationships change across a variety of spatial–temporal scales.MethodsWe recorded the afternoon acoustic environment during the spring of 2016 at 30 locations in the city of Innsbruck, Austria using a spatially balanced random sampling design. We quantified the total acoustic environment with the sound exposure level (SEL) metric, and developed a new metric, percent biophony (PB), to quantify biophony while avoiding noise bias. We quantified relationships with land cover (LC) classes, as well as a landscape index, distance to nature (D2N), across 10 scales.ResultsD2N within 1280 m best predicted PB, while both the LC class trees and D2N within 40 m best predicted SEL. PB increased more throughout the spring at locations with more natural surrounding LC, while PB did not change significantly at locations with more urban surrounding LC.ConclusionsLC and composite indices can serve as reasonable predictors for the acoustic environment; however, the relationships are scale dependent. Mapping soundscapes can help to illustrate possible driving mechanisms and provide a valuable tool for urban management and planning.

Production of English tense and lax vowels by young speakers of Korean dialects

This study attempts to examine whether there is any difference in the acoustic properties of English tense and lax vowels by young speakers of Korean regional dialect speakers. A production test is developed to analyze acoustic manifestations of four phonetic parameters (F1, F2, vowel duration, and vowel distance) in English speech of Kyunggi Korean (KK) and North Kyungsang Korean (NKK) dialect speakers. The 184 collected data for the production test consisting of high vowels /i, ɪ, u, ʊ/ in CVC structure are taken from 20 female elementary school students (10 for each dialect group). The result shows no significant difference between two regional dialects, which indicates similar features of acoustic properties are uttered by both groups. However, despite this similarity between two groups, results from comparative analysis with native speakers show that NKK uses less vowel space from the calculated acoustic distance (Euclidean distance). Therefore, it can be argued that discrepancy in overall acoustic properties between young NKK and KK is insignificant but still distinguishing acoustic space of vowel would be harder for NKK. Based on these findings pedagogical implication for effective articulation training has been suggested.

Robust Estimation of Hypernasality in Dysarthria with Acoustic Model Likelihood Features.

Hypernasality is a common characteristic symptom across many motor-speech disorders. For voiced sounds, hypernasality introduces an additional resonance in the lower frequencies and, for unvoiced sounds, there is reduced articulatory precision due to air escaping through the nasal cavity. However, the acoustic manifestation of these symptoms is highly variable, making hypernasality estimation very challenging, both for human specialists and automated systems. Previous work in this area relies on either engineered features based on statistical signal processing or machine learning models trained on clinical ratings. Engineered features often fail to capture the complex acoustic patterns associated with hypernasality, whereas metrics based on machine learning are prone to overfitting to the small disease-specific speech datasets on which they are trained. Here we propose a new set of acoustic features that capture these complementary dimensions. The features are based on two acoustic models trained on a large corpus of healthy speech. The first acoustic model aims to measure nasal resonance from voiced sounds, whereas the second acoustic model aims to measure articulatory imprecision from unvoiced sounds. To demonstrate that the features derived from these acoustic models are specific to hypernasal speech, we evaluate them across different dysarthria corpora. Our results show that the features generalize even when training on hypernasal speech from one disease and evaluating on hypernasal speech from another disease (e.g., training on Parkinson's disease, evaluation on Huntington's disease), and when training on neurologically disordered speech but evaluating on cleft palate speech.

The Language-specific Use of Fundamental Frequency Rise in Segmentation of an Artificial Language: Evidence from Listeners of Taiwanese Southern Min.

Experience with native-language prosody encourages language-specific strategies for speech segmentation. Conflicting findings from previous research suggest that these strategies may not be abstracted away from the acoustic manifestation of prosodic features in the native speech. Using the artificial language learning paradigm, the current study explores this possibility in connection with listeners of a lexical tone language called Taiwanese Southern Min (TSM). In TSM, the only rising lexical tone occurs almost only on the final syllable of the language's tone sandhi domain and is phonetically associated with final lengthening. Based on these observations, Experiment I examined what constituted a sufficient finality cue for use by TSM listeners to support segmentation: (a) final fundamental frequency (F0) rise only; or (b) final F0 rise conjoined with final lengthening. The results showed that segmentation was inhibited by the former cue but facilitated by the latter. Experiment II showed that the facilitation cannot be attributed entirely to final lengthening, as a null effect was found when final lengthening was the sole prosodic cue to segmentation. It is thus assumed that acoustic details as fine-grained as the lengthening of the rising tone are involved in the modulation of the segmentation strategy whereby TSM listeners perceive F0 rise as signaling finality. The inhibitory effect of final F0 rise alone found in Experiment I motivated Experiment III, which revealed that initial F0 rise in the absence of lengthening cues improved TSM listeners' segmentation. It is speculated that such use of initial F0 rise might reflect a cross-linguistic segmentation solution.

Acoustic manifestations of “narrow focus” in Apurímac Quechua vowels

This paper investigates the acoustic manifestations of “narrow focus” on the vowels of Apurímac Quechua. Specifically, the three acoustic correlates of duration, intensity, and mean F0 in the vowels of stressed syllables were measured to see how narrow focusis expressed and if it would have a significant enhancing effect on the target vowels /a/, /i/, and /u/. 180 tokens were used in this experimental study, 90 in “focus” condition and 90 in “non-focus” condition (30 for each vowel in both conditions). Paired t-tests were conducted for each correlate, and the results show that duration is significantly longer (p < 0.01) in focus condition (mean = 47.22 ms, SD = 10.84) compared to non-focus condition (mean = 47.22 ms, SD = 10.84). The same pattern is found for intensity where vowels in focus condition (mean = 66.44 dB, SD = 4.85) were a significantly louder (p < 0.01) than the vowel in non-focus condition (mean = 63.02, SD = 5.27). Finally, the mean F0 for vowels in focus condition (mean = 135.41 Hz, SD = 16.45) was significantly higher (p < 0.01) than the non-focus condition (mean = 117.41). While all correlates show significant increase as a result of being in a focus condition, the duration correlate did not cross the “Just Noticeable Difference” (JND) threshold of 10 ms. On the other hand, intensity and F0 crossed the JND of 3 dB and 1 Hz, respectively. These findings suggest that Apurímac Quechua is a syllable-timed language that does not rely on duration as a primary acoustic correlate of “narrow focus.”

ACOUSTICS OF PROCESS AS A FACTOR OF FORMING IN THE COMBUSTION ZONE OF FORMATIONS WITH EXCESS CHARGE

The nature and mechanism of formation and reproduction in time of macroscopic, fluctuational nature of formations with uncompensated electric charge (aquazineutral or AQN-formations) fixed by observations in the burning zone are investigated. With account of characteristic to combustion acoustic manifestations it is shown, that when burning in the reacting medium are necessarily developed instabilities in the distribution of electrical charge over the volume.It is substantiated, that the excitation conditions and the general features of charge instabilities in distribution of charge over volume really determine the mechanism under study as factor jointly providing of both the formation and continuous reproduction of AQN-formations in the combustion zone (in the pre-flame region, first of all).

한국인의 영어 발음 양상에 관한 음성학적 연구: 외래어를 중심으로

The purpose of the current study is to investigate acoustic manifestations of English stress uttered by Korean English learners and to discuss instructional methods to help to correct prosodic errors if any. This study employed a “listen-and-repeat” strategy using loanwords and their reiterant counterparts as well to test effectiveness of practice. The overall results exhibited positive effects of practice on using acoustic cues including duration, F0 and intensity of vowels. In addition, reiterant speech more explicitly showed the effectiveness of practice, and it can be said that Korean English learners benefitted from reiterant speech in that it exhibits acoustic correlates more clearly and thus helps L2 learners recognize the prosodic features and employ them.

A cross-linguistic study of phonetic correlates of metrical structure in under-documented languages

Although languages with rhythmic stress have been extensively described and analyzed in the phonology literature, there has been little phonetic verification of the metrical structures suggested by these stress patterns. This paper presents results of a cross-linguistic study of the acoustic correlates of foot structure in several under-documented languages with morphologically complex words providing the necessary backdrop for the realization of rhythmic metrical structure. Various potential acoustic exponents of metrical structure are considered, including duration, F0, intensity, and formant frequencies. The targeted languages include Muskogean languages of the United States (Koasati, Muskogee, and Chickasaw), Circassian languages spoken primarily in Turkey and Russia (Kabardian and Adyghe), the Tukanoan language Kubeo of Brazil and Colombia, and the Arawak language Mojeno Trinitario of Bolivia. The languages differ in their foot templates (trochaic vs. iambic), the direction of their metrical parse (left-to-right vs. right-to-left), their degree of metrical rhythm, and whether they also possess lexical tone or not. Results suggest considerable diversity in the acoustic manifestations of metrical structure (including the possibility of lack of rhythmic feet even in long words) and in the relationship between the word-level metrical system and other prosodic features, including intonation and (in tonal languages) lexical tone.Although languages with rhythmic stress have been extensively described and analyzed in the phonology literature, there has been little phonetic verification of the metrical structures suggested by these stress patterns. This paper presents results of a cross-linguistic study of the acoustic correlates of foot structure in several under-documented languages with morphologically complex words providing the necessary backdrop for the realization of rhythmic metrical structure. Various potential acoustic exponents of metrical structure are considered, including duration, F0, intensity, and formant frequencies. The targeted languages include Muskogean languages of the United States (Koasati, Muskogee, and Chickasaw), Circassian languages spoken primarily in Turkey and Russia (Kabardian and Adyghe), the Tukanoan language Kubeo of Brazil and Colombia, and the Arawak language Mojeno Trinitario of Bolivia. The languages differ in their foot templates (trochaic vs. iambic), the direction of their metrical parse (l...

非発話末におけるロシア語word-final devoicingの音響的実現

非発話末におけるロシア語word-final devoicingの音響的実現

Acoustic Manifestations of a Gas Inclusion Near an Interface

The study continues previous investigations based on the use of specific (bispherical) coordinates in describing the behavior of bubbles in the presence of bounding surfaces. Explicit dependences of the first oscillation modes and the scattered field on bubble size, distance to the boundary, and physical parameters of contacting media are obtained. It is shown that, as the distance to the boundary decreases, dipole oscillations acquire resonance nature and become comparable in amplitude with radial oscillations. This effect is of applied value for modern ultrasonic cleaning techniques, because it leads to a considerable increase in bubble-generated microstreaming.

Acoustic Manifestation of English Lexical Stress Pattern by Native Erei Speakers

Lexical stress is the combination of intensity, fundamental frequency and vowel quality acoustically. Like many other non-segmental features of English, it is very vital for intelligibility, foreign accentedness and comprehensibility since wrong placement of primary and/or secondary stress in English words might lead to different interpretations. The feature is not observable in Erei, which is a tonal language, where all the syllables or vowels in a word are given strong form. Erei language is different from free variable stress system of English, and the difference between the two languages may likely result in the transfer of Erei tonal system in the articulation of English lexical stress by native Erei speakers. The study examined the deployment of English lexical stress in the speech outputs of Erei-English bilingual speakers in Biase Local Government Area of Cross River State Nigeria. Eight subjects were selected from four secondary schools. Eight words, selected from Cruttenden’s Gimson’s pronunciation of English, were used for the analysis. The metrical theory, developed by Lieberman (1975), was adopted as the framework for the analysis. Findings indicated that Erei-English bilinguals place stress on the wrong syllables as shown in the native British speaker’s output, and therefore, do not observe English rhythmic alternation rules. All the syllables in a word are almost given equal prominence, a rehash of the tonal nature of Erei, affecting the intelligibility of their spoken English. Based on the findings, the study suggested the availability of well-equipped language laboratories, provision of sophisticated audio-visual aids and computerised speech equipment in Nigeria as well as language teachers in L2 situations should focus instruction on non-segmental features before the individual segments to promote international intelligibility in the speech outputs of L2 users.

Finding word boundaries in Indian English-accented speech

The majority of English nouns, verbs, and adjectives begin with a stressed syllable, and listeners exploit this tendency to help parse the continuous stream of speech into individual words. However, the acoustic manifestation of stress depends on the variety of English being spoken. In two visual world eye-tracking experiments, we tested if Indian English-accented speech causes Canadian English listeners to make stress-based segmentation errors. Participants heard Canadian- or Indian-accented trisyllabic sequences that could be segmented in two ways, depending on the perceived location of stress. For example, [hæ.pi.tsə] could be segmented as happy/[tsə] if it is perceived to have stress on the first syllable or as [hæ]/pizza if it is perceived to have stress on the second syllable. Results suggest that Indian English-accented speech impairs segmentation in Canadian listeners, and that both accented pitch and other features of the Indian English accent contribute to segmentation difficulties. Findings are interpreted with respect to models of how similarity between two languages impacts the listener’s ability to segment words from the speech stream.