Fundamental Frequency Contours Research Articles

Dynamic analysis of doubly curved composite panels using lamination parameters and spectral-Tchebychev method

Efficient modeling and optimization techniques are required to overcome the high design complexity and computational costs concerning the engineering of composite structures. In this paper, a modeling framework for the dynamic analysis of doubly curved composite panels is developed. Lamination parameters are used to characterize the stiffness properties of the laminate, and the responses are calculated through the two-dimensional spectral-Tchebychev method. The proposed framework combines the computational efficiency advantages of both lamination parameters formulation and spectral-Tchebychev method which is extended for dynamic analysis of curved composite laminates. Compared to the finite element method, the developed model significantly decreases the computation duration, thereby leading to analysis speed-ups up to 40 folds. In the case studies, fundamental frequency contours for the doubly curved composite panels are obtained in lamination parameters space for the first time. The results show that, unlike flat or singly curved laminates, the maximum frequency design points for doubly curved panels can be inside the feasible region of lamination parameters requiring multiple layer angles. The fundamental mode shapes for the maximum frequency designs are also computed to investigate the influence of panel curvatures on the vibration patterns, which can exhibit mode switching phenomenon.

From modulated noise to natural speech: The effect of stimulus parameters on the envelope following response

Envelope following responses (EFRs) can be evoked by a wide range of auditory stimuli, but for many stimulus parameters the effect on EFR strength is not fully understood. This complicates the comparison of earlier studies and the design of new studies. Furthermore, the most optimal stimulus parameters are unknown. To help resolve this issue, we investigated the effects of four important stimulus parameters and their interactions on the EFR. Responses were measured in 16 normal hearing subjects evoked by stimuli with four levels of stimulus complexity (amplitude modulated noise, artificial vowels, natural vowels and vowel-consonant-vowel combinations), three fundamental frequencies (105 Hz, 185 Hz and 245 Hz), three fundamental frequency contours (upward sweeping, downward sweeping and flat) and three vowel identities (Flemish /a:/, /u:/, and /i:/). We found that EFRs evoked by artificial vowels were on average 4–6 dB SNR larger than responses evoked by the other stimulus complexities, probably because of (unnaturally) strong higher harmonics. Moreover, response amplitude decreased with fundamental frequency but response SNR remained largely unaffected. Thirdly, fundamental frequency variation within the stimulus did not impact EFR strength, but only when rate of change remained low (e.g. not the case for sweeping natural vowels). Finally, the vowel /i:/ appeared to evoke larger response amplitudes compared to /a:/ and /u:/, but analysis power was too small to confirm this statistically. Vowel-dependent differences in response strength have been suggested to stem from destructive interference between response components. We show how a model of the auditory periphery can simulate these interference patterns and predict response strength. Altogether, the results of this study can guide stimulus choice for future EFR research and practical applications.

Production-perception relationship of Mandarin tones as revealed by critical perceptual cues.

The relationship of lexical tone production and perception has not been well studied. Using Mandarin tone, this research tests the hypothesis that a production-perception link is revealed by critical perceptual cues. The critical status of perceptual tonal cues was determined by perceptual cue weights, showing fundamental frequency (F0) contour as being more critical than height. Then, tone production features were examined for critical F0 contour (slope, curvature, turning-point location) and non-critical F0 height (mean, onset) cues. A production-perception correlation was found for F0 contour but not height cues, suggesting that critical perceptual cues dictate the relationship between production and perception.

Monophthongisation and Vowel Lengthening in Educated Ibibio English

The major preoccupation of this paper is to study monophthongisation and vowel lengthening in Educated Ibibio English with a view to explaining the lengthening of vowels in final open stressed syllables. Educated Ibibio English (here after EIE) is an ethnic variety of Nigerian English spoken by literate home-grown Ibibio people in Akwa Ibom State, Nigeria. Monophthongisation is a phonological process whereby one of two vowel elements of a diphthong, usually the second (offset) element, is deleted, leaving the stranded stressed (onset) to be lengthened, if found in final open, stressed syllable. Related works on EIE segments indicate that some Standard British English (SBE) closing diphthongs /?u/ and /ei/ tend to monophthongise to /e/ and /o/, respectively. The study employs the Moraic Theory of Hyman and Hayes which main argument is that the syllable contains neither onset or a rhyme. Rather, every syllable contains one or more Mora. Also, a Speech Filling System (SFS/WASP) Computerized Speech Laboratory was used to interpret Fo curve structure and acoustic duration in order to corroborate findings from perceptual analysis. The study establishes the fact that the monophthongised diphthongs were lengthened becuaseof the need to preserve the weight of the deleted /u/ and /i/ in SBE /ei/ and /??/ diphthongs and also to reflect components of the failing fundamental frequency (Fo) contour of English fnal open syllable.

Prosodic word boundary detection from Bengali continuous speech

Detection of word boundaries in continuous speech is a tedious process due to the absence of a definite pause or silence in the word boundary position. Thus, continuous speech recognition is a very challenging task. However, the prosodic word boundaries, unlike the written word boundaries, can be predicted using the prosodic parameters of continuous speech. This paper proposes a method for detecting such prosodic word boundaries from Bengali continuous speech. Bengali is a bound-stress language, where stress is observed on the first syllable of a prosodic word. Empirical Mode Decomposition is applied to the logarithm of fundamental frequency (F0) contour of continuous speech to detect prosodic word boundaries. 200 Bengali readout sentences, read by ten speakers, are analyzed for the present work. An overall prosodic boundary detection accuracy of 88.05% is achieved, whereas precision and recall values are 90.73% and 88.31%, respectively, with f-score as 89.5. A prosodic word dictionary comprising 5031 prosodic words has been developed by analyzing 1526 Bengali sentences with the proposed prosodic word boundary detection method.

Speech emotion recognition using discriminative dimension reduction by employing a modified quantum-behaved particle swarm optimization algorithm

In recent years, Speech Emotion Recognition (SER) has received considerable attention in affective computing field. In this paper, an improved system for SER is proposed. In the feature extraction step, a hybrid high-dimensional rich feature vector is extracted from both speech signal and glottal-waveform signal using techniques such as MFCC, PLPC, and MVDR. The prosodic features derived from fundamental frequency (f0) contour are also added to this feature vector. The proposed system is based on a holistic approach that employs a modified quantum-behaved particle swarm optimization (QPSO) algorithm (called pQPSO) to estimate both the optimal projection matrix for feature-vector dimension reduction and Gaussian Mixture Model (GMM) classifier parameters. Since the problem parameters are in a limited range and the standard QPSO algorithm performs a search in an infinite range, in this paper, the QPSO is modified in such a way that it uses a truncated probability distribution and makes the search more efficient. The system works in real-time and is evaluated on three standard emotional speech databases Berlin database of emotional speech (EMO-DB), Surrey Audio-Visual Expressed Emotion (SAVEE) and Interactive Emotional Dyadic Motion Capture (IEMOCAP). The proposed method improves the accuracy of the SER system compared to classical methods such as FA, PCA, PPCA, LDA, standard QPSO, wQPSO, and deep neural network, and also outperforms many state-of-the-art recent approaches that use the same datasets.

The effect of target/masker fundamental frequency contour similarity on masked-speech recognition.

Greater informational masking is observed when the target and masker speech are more perceptually similar. Fundamental frequency (f0) contour, or the dynamic movement of f0, is thought to provide cues for segregating target speech presented in a speech masker. Most of the data demonstrating this effect have been collected using digitally modified stimuli. Less work has been done exploring the role of f0 contour for speech-in-speech recognition when all of the stimuli have been produced naturally. The goal of this project was to explore the importance of target and masker f0 contour similarity by manipulating the speaking style of talkers producing the target and masker speech streams. Sentence recognition thresholds were evaluated for target and masker speech that was produced with either flat, normal, or exaggerated speaking styles; performance was also measured in speech spectrum shaped noise and for conditions in which the stimuli were processed through an ideal-binary mask. Results confirmed that similarities in f0 contour depth elevated speech-in-speech recognition thresholds; however, when the target and masker had similar contour depths, targets with normal f0 contours were more resistant to masking than targets with flat or exaggerated contours. Differences in energetic masking across stimuli cannot account for these results.

TENT: Technique-Embedded Note Tracking for Real-World Guitar Solo Recordings

The employment of playing techniques such as string bend and vibrato in electric guitar performance makes it difficult to transcribe the note events using general note tracking methods. These methods analyze the contour of fundamental frequency computed from a given audio signal, but they do not consider the variation in the contour caused by the playing techniques. To address this issue, we present a model called technique-embedded note tracking (TENT) that uses the result of playing technique detection to inform note event estimation. We evaluate the proposed model on a dataset of 42 unaccompanied lead guitar phrases. Our experiments showed that TENT can nicely recognize complicated skills in monophonic guitar solos and improve the F-score of note event estimation by 14.7% compared to an existing method. For reproducibility, we share the Python source code of our implementation of TENT at the following GitHub repo: https://github.com/srviest/SoloLa .

A transversal study of fundamental frequency contours in parkinsonian voices

A transversal study of the pitch variability of parkinsonian voices in read speech is presented. 30 patients suffering from Parkinson's disease (PD) and 32 healthy speakers were recorded while reading a text without voiceless phonemes. The fundamental frequency contours were calculated from the recordings, and the following measures were used for describing them: mean, minimum, maximum, and standard deviation of the estimated fundamental frequencies. Results based on these measures indicate that the influence of PD on some aspects of intonation can be masked by the effects of aging, especially for male voices. However, some parameters such as the relative fundamental frequency range exhibit lower correlations with age than with PD stage, as evaluated using the Hoehn and Yahr scale. These correlations between relative fundamental frequency range and PD stage reach moderate-to-high values in the case of women.Additionally, three parameters describing the form of the fundamental frequency modulation spectrum were investigated for correlation with age and PD stage. The study of this modulation spectrum provides some insight into the ability of the speakers to plan the intonation of full phrases. For both male and female populations, significant correlations were found between parameters obtained from the modulation spectrum of fundamental frequency and the PD stage. Nevertheless, the quantitative assessment of the performance of regression models built from these modulation parameters and fundamental frequency range suggests that such measures are likely to be of limited value in the early diagnosis of PD due to inter-speaker variability.

Predicting glottal closure insufficiency using fundamental frequency contour analysis

Voice analysis has a limited role in a day-to-day voice clinic. We developed objective measurements of vocal folds (VF) glottal closure insufficiency (GCI) during phonation. We examined 18 subjects with no history of voice impairment and 20 patients with unilateral VF paralysis before and after injection medialization laryngoplasty. Voice analysis was extracted. We measured settling time, slope, and area under the fundamental frequency curve from the phonation onset to its settling-time. The measured parameters, settling time, slope, and area under the curve were in correlation with the traditional acoustic voice assessments and clinical findings before treatment and after injection medialization laryngoplasty. We found that the fundamental frequency curve has several typical contours which correspond to different glottal closure conditions. We proposed a new set of parameters that captures the contour type, and showed that they could be used to quantitatively assess individuals with GCI.

The acoustic correlates of quantity in Inari Saami

This paper studies the phonetic realisation of the ternary length opposition of consonants in Inari Saami disyllabic feet focussing on the distinction between half-long and long geminates. Inari Saami is compared with other Saami and Finnic languages. Segmental durations, fundamental frequency and intensity are analysed. The results show a three-way distinction in consonant duration most robustly after a short stressed syllable vowel. In the case of a long stressed syllable vowel there is no difference between half-long and long geminates. In all of the analysed word structures, segments are inversely related to each other, as with an increase in consonant duration the durations of the surrounding vowels decrease. The fall in the fundamental frequency contour is less steep in words with a long geminate than in those with a short consonant or a half-long geminate. The intensity of the unstressed vowel decreases with the increasing quantity of the intervocalic consonant. The results indicate that the three-way quantity distinction in Inari Saami is primarily manifested by durational properties in a disyllabic foot, while fundamental frequency and intensity have a less important role.

Auditory Brainstem Representation of the Voice Pitch Contours in the Resolved and Unresolved Components of Mandarin Tones.

Accurate perception of voice pitch plays a vital role in speech understanding, especially for tonal languages such as Mandarin. Lexical tones are primarily distinguished by the fundamental frequency (F0) contour of the acoustic waveform. It has been shown that the auditory system could extract the F0 from the resolved and unresolved harmonics, and the tone identification performance of resolved harmonics was better than unresolved harmonics. To evaluate the neural response to the resolved and unresolved components of Mandarin tones in quiet and in speech-shaped noise, we recorded the frequency-following response. In this study, four types of stimuli were used: speech with either only-resolved harmonics or only-unresolved harmonics, both in quiet and in speech-shaped noise. Frequency-following responses (FFRs) were recorded to alternating-polarity stimuli and were added or subtracted to enhance the neural response to the envelope (FFRENV) or fine structure (FFRTFS), respectively. The neural representation of the F0 strength reflected by the FFRENV was evaluated by the peak autocorrelation value in the temporal domain and the peak phase-locking value (PLV) at F0 in the spectral domain. Both evaluation methods showed that the FFRENV F0 strength in quiet was significantly stronger than in noise for speech including unresolved harmonics, but not for speech including resolved harmonics. The neural representation of the temporal fine structure reflected by the FFRTFS was assessed by the PLV at the harmonic near to F1 (4th of F0). The PLV at harmonic near to F1 (4th of F0) of FFRTFS to resolved harmonics was significantly larger than to unresolved harmonics. Spearman's correlation showed that the FFRENV F0 strength to unresolved harmonics was correlated with tone identification performance in noise (0 dB SNR). These results showed that the FFRENV F0 strength to speech sounds with resolved harmonics was not affected by noise. In contrast, the response to speech sounds with unresolved harmonics, which were significantly smaller in noise compared to quiet. Our results suggest that coding resolved harmonics was more important than coding envelope for tone identification performance in noise.

Aging effects on categorical perception of Mandarin tones in noise

The current study aimed at investigating the aging effect on the categorical perception of Mandarin lexical tones with varied fundamental frequency (F0) contours in noise. Mandarin tone identification and tone discrimination in quiet and noise were measured for younger and older listeners in a categorical perception paradigm where the stimuli continua varied their F0 contour systematically from the level to the rising/falling tones. Results reported that older listeners, in contrast with their younger counterparts, performed with less stimulus-tuned changes in both identification and discrimination functions and smaller peakedness in the discrimination function for both level-rising and level-falling tones. The aging effects on Mandarin tone categoricality were observed in both quiet and noise. Moreover, noise aggravated the aging effects, especially with the high SNR condition. Plus, older listeners’ identification and discrimination functions in CP paradigm positively correlated with their performance in general speech identification in noise; such correlation was not found with younger listeners. Our study suggested that older listeners had less categoricality in both identification and discrimination functions for the level-rising and level-falling tones, probably due to the aging-related decline in temporal processing.

Tonal Neutralization of Taiwanese Checked and Smooth Syllables: An Acoustic Study.

Taiwanese tonal alternation is realized in a circular chain shift fashion for both smooth and checked syllables. Debate regarding the processes of less productive Taiwanese tonal alternation has centered on whether a surface tone is derived from an underlying tone, or whether a surface tone is selected without undergoing any derivation. The current study investigates this controversial issue by examining Taiwanese checked tone and smooth tone sandhi neutralization in production. In particular, we analyzed whether checked citation and sandhi tone 53 (C21→C53), checked citation and sandhi tone 21 (C53→C21), smooth citation and sandhi tone 55 (S51→S55), and smooth citation and sandhi tone 21 (S33→S21) are acoustically completely neutralized in fundamental frequency (F0) height, contour, and duration. A non-sandhi exception was also included to evaluate the effect of position-in-word on F0 height and duration given that citation tones always appear in phrase-final position. Any trace of influence from the underlying representation would indicate a computational mechanism, whereas the absence of any trace would suggest a lexical mechanism for the production of Taiwanese tonal alternation. Results did not show any influence of F0 height, F0 contour, or tone duration from the underlying representation for both checked and smooth tones, supporting a lexical mechanism in speech production for less productive tonal alternations.

Effects of fundamental frequency contour on understanding Mandarin sentences in bimodal hearing simulations.

Fundamental frequency (F0) contour carries important information for understanding a tonal language. The present work assessed the effects of F0 contour on understanding Mandarin sentences in bimodal hearing simulations, including three conditions of acoustic-only, electric-only, and combined stimulations. Test stimuli were synthesized Mandarin sentences, each word with a normal, flat, or randomly assigned lexical tone, and presented to normal-hearing Mandarin-speaking listeners to recognize. Experimental results showed that changing F0 contour significantly affected the perception of Mandarin sentences under all conditions of acoustic-only, electric-only, and combined stimulations. The combined-stimulation advantage was only observed for test stimuli with the normal F0 contour.

Design of curved composite panels for optimal dynamic response using lamination parameters

Abstract In this paper, dynamic response of composite panels is investigated using lamination parameters as design variables. Finite element analyses are performed to observe the individual and combined effects of different panel aspect ratios, curvatures and boundary conditions on the dynamic responses. Fundamental frequency contours for curved panels are obtained in lamination parameters domain and optimal points yielding maximum values are found. Subsequently, forced dynamic analyses are carried out to calculate equivalent radiated power (ERP) for the panels under harmonic pressure excitation. ERP contours at the maximum fundamental frequency are presented. Optimal lamination parameters providing minimum ERP are determined for different excitation frequencies and their effective frequency bands are shown. The relationship between the designs optimized for maximum fundamental frequency and minimum ERP responses is investigated to study the effectiveness of the frequency maximization technique. The results demonstrate the potential of using lamination parameters technique in the design of curved composite panels for optimal dynamic response and provide valuable insight on the effect of various design parameters.

Understanding low-pass-filtered Mandarin sentences: Effects of fundamental frequency contour and single-channel noise suppression.

The present work assessed the effects of flattening the fundamental frequency (F0) contour and processing by single-channel noise suppression on the intelligibility of low-pass (LP)-filtered (LPF) sentences. The original F0 contour was replaced by an average flat F0 contour or treated by single-channel noise suppression, followed by application of LP filtering to Mandarin sentences. Processed stimuli were presented to normal-hearing listeners to recognize. Flattening the F0 contour significantly affected the understanding of LPF sentences. Noise suppression by existing single-channel algorithms did not improve the intelligibility of LPF sentences.

The effect of F0 contour on the intelligibility of speech in the presence of interfering sounds for Mandarin Chinese.

In Mandarin Chinese, the fundamental frequency (F0) contour defines lexical "Tones" that differ in meaning despite being phonetically identical. Flattening the F0 contour impairs the intelligibility of Mandarin Chinese in background sounds. This might occur because the flattening introduces misleading lexical information. To avoid this effect, two types of speech were used: single-Tone speech contained Tones 1 and 0 only, which have a flat F0 contour; multi-Tone speech contained all Tones and had a varying F0 contour. The intelligibility of speech in steady noise was slightly better for single-Tone speech than for multi-Tone speech. The intelligibility of speech in a two-talker masker, with the difference in mean F0 between the target and masker matched across conditions, was worse for the multi-Tone target in the multi-Tone masker than for any other combination of target and masker, probably because informational masking was maximal for this combination. The introduction of a perceived spatial separation between the target and masker, via the precedence effect, led to better performance for all target-masker combinations, especially the multi-Tone target in the multi-Tone masker. In summary, a flat F0 contour does not reduce the intelligibility of Mandarin Chinese when the introduction of misleading lexical cues is avoided.

Categorical Perception of Mandarin Chinese Tones 1-2 and Tones 1-4: Effects of Aging and Signal Duration.

The purpose of this study was to investigate the aging effect on the categorical perception of Mandarin Chinese tones with varied fundamental frequency (F0) contours and signal duration. Both younger and older native Chinese listeners with normal hearing were recruited in 2 experiments: tone identification and tone discrimination on a series of stimuli with the F0 contour systematically varying from the flat tone to the rising-falling tones. Apart from F0 contour, tone duration was manipulated at 3 levels: 100, 200, and 400 ms. Results suggested that, compared with younger listeners, older listeners performed with shallower slope in the identification function and smaller peakedness in the discrimination function, particularly for Tones 1 and 2, whereas for Tones 1 and 4, comparable categorical perception was found between younger and older listeners. The current study suggested that longer duration facilitated categorical perception in the flat-rising tones for the older listeners. Such an aging effect was not found with the flat-falling tones, suggesting that the aging-related deficit in categorical perception might relate to different tone types. Aging resulted in less categoricality of Mandarin tone perception for the flat-rising tones with short duration like 100 ms, possibly due to the aging-related decline in temporal processing.

The underlying mechanism of deficits of speech comprehension and hallucinations in Chinese patients with schizophrenia

Sentence context and fundamental frequency (F0) contours are important factors to speech perception and comprehension. In Chinese-Mandarin, lexical tones can be distinguished by the F0 contours. Previous studies found healthy people could use the cue of context to recover the phonological representations of lexical tones from the altered tonal patterns to comprehend the sentences in quiet condition, but can not in noise environment. Lots of research showed that patients with schizophrenia have deficits of speech perception and comprehension. However, it is unclear how context and F0 contours influence speech perception and comprehension in patients with schizophrenia. This study detected the contribution of context and lexical tone to sentence comprehension in four types of sentences by manipulating the context and F0 contours in 32 patients with schizophrenia and 33 healthy controls. The results showed that (1) in patients with schizophrenia, the interaction between context and F0 contour was not significant, which was significant in healthy controls; (2) the scores of sentences with two types of sentences with flattened F0 contours were negatively correlated with hallucination trait scores; (3) the patients with schizophrenia showed significantly lower scores on the intelligibility of sentences in all conditions, which were negatively correlated with PANSS-P. The patients with schizophrenia couldn't use the cue of context to recover the phonological representations of lexical tones from the altered tonal patterns when they comprehend the sentences, inner noise may be the underlying mechanism for the deficits of speech perception and comprehension.