• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1503-1512
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• 1988

As the basic analysis to solve the within-and cross-speaker variability in phoneme based speech recognition, changes in pitch and formant frequencies of 8 Korean vowels with age and sex of speaker has been investigated by analyzing a large number fo samples. Conclusions obtained are as follows: 1) Changes in pitch frequency with age and sex of speaker for children are hard to distinguish and the difference of before and after the voice change is analyzed approximately 0.2 oct. for female an 0.9 oct. for male. 2) While most of the formants of vowel considerably change with the age of speaker, the change becomes smaller as the age becomes older. 3) While there is an indirect correlation between pitch and formant with change in age, it is hard to see a direct correlation. 4) When the objects of the recognition experiment by pitch and formants are various speakers in each age and sex, pitch also works as an efficient recognition parameter.

• Journal of Korea Multimedia Society
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• v.22 no.7
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• pp.749-758
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• 2019

This paper proposes a data augmentation algorithm to improve the performance of DNN(Deep Neural Network) based speech enhancement. Many deep learning models are exploring algorithms to maximize the performance in limited amount of data. The most commonly used algorithm is the data augmentation which is the technique artificially increases the amount of data. For the effective data augmentation algorithm, we used a formant enhancement method that assign the different weights to the formant frequencies. The DNN model which is trained using the proposed data augmentation algorithm was evaluated in various noise environments. The speech enhancement performance of the DNN model with the proposed data augmentation algorithm was compared with the algorithms which are the DNN model with the conventional data augmentation and without the data augmentation. As a result, the proposed data augmentation algorithm showed the higher speech enhancement performance than the other algorithms.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.239-246
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• 2017

This paper compares the speech signal parameters between Korean and Chinese for Korean pronunciation /ㄹ/, which is caused many errors by Chinese leaners. Allophones of /ㄹ/ in Korean is divided into lateral group and tap group. It has been investigated the reasons for these errors by studying the similarity and the differences between Korean /ㄹ/ pronunciation and its corresponding Chinese pronunciation. In this paper, for the purpose of comparison the speech signal parameters such as energy, waveform in time domain, spectrogram in frequency domain, pitch based on ACF, Formant frequencies are used. From the phonological perspective the speech signal parameters such as signal energy, a waveform in the time domain, a spectrogram in the frequency domain, the pitch (F0) based on autocorrelation function (ACF), Formant frequencies (f1, f2, f3, and f4) are measured and compared. The data, which are composed of the group of Korean words by through a philological investigation, are used and simulated in this paper. According to the simulation results of the energy and spectrogram, there are meaningful differences between Korean native speakers and Chinese leaners for Korean /ㄹ/ pronunciation. The simulation results also show some differences even other parameters. It could be expected that Chinese learners are able to reduce the errors considerably by exploiting the parameters used in this paper.

• The Journal of the Acoustical Society of Korea
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• v.3 no.1
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• pp.25-35
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• 1984

This paper analysis the Dynamic Time Warping algorithms for time normalization of speech pattern and discusses the Dynamic Programming algorithm for spoken Korean isolated digits recognition. In the DP matching, feature vectors of the reference and test pattern are consisted of first three formant frequencies extracted by power spectrum density estimation algorithm of the ARMA model. The major differences in the various DTW algorithms include the global path constrains, the local continuity constraints on the path, and the distance weighting/normalization used to give the overall minimum distance. The performance criterias to evaluate these DP algorithms are memory requirement, speed of implementation, and recognition accuracy.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.26 no.2
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• pp.104-111
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• 2015

Background and Objectives : Acoustic analysis of voice could be influenced so much by the quality of voice files which were recorded by recording device. In clinical practice, voice files that were recorded by analysis program directly or portable digital recording device were analyzed mostly. This study examined the feasibility of using Galaxy smartphone recordings for acoustic analysis of voice. Materials and Methods : Acoustic measures were compared between voice signals recorded from 30 normal speakers (15 males and 15 females) through Galaxy smartphone, portable digital recording device and CSL. Fo, jitter, shimmer, NHR (Noise-Harmony ratio) and Formant frequencies were analyzed by MDVP. Results : Fo, Jitter, Shimmer, NHR and formant frequencies from 3 devices were no significantly difference. The intraclass correlation coefficient (ICC) was higher between each of the voice perturbation measures. Conclusion : The findings indicated that Galaxy smartphone recording system was useful device for acoustic analysis of voice. Furthermore, Galaxy smartphone can be applied widely in various way for acoustic analysis of voice.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.521-528
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• 1996

This presentation explores on the perceptual characteristics of the lateral sound /l/ in CV syllables. At initial position we found that /l/ has well marked formant transitions. Then several questions arise: 1) are these formant structures dependent on the following vowel\ulcorner. 2) Are the formant transitions giving an additional cue for the identification\ulcorner Considering that the French vocalic system presents a greater variety of vowels than Spanish, several experiments were designed to verify to what extent a more extensive range of vocalic timbres contribute to the perception of /l/. Natural emissions of /l/ produced in Argentine Spanish and Canadian French CV syllables were recorded, where V was successively /i, e, a, o, u/ for Spanish and /i, e, $\varepsilon$, a, $\alpha$, o, u, y, \phi$/ for French. For each item, the segment C was maintained and V was replaced by cutting & splicing by each of the remaining vowels without transitions. Results of the identification tests for Spanish show that natural /l/ segments with low Fl and high formants F3, F4 can be clearly identified in the /i, e, u/ vowel contexts without transitions. For French subjects the combination of /l/ with a vowel without transitions reflected correct identifications for its own original vowel context in /e, $\varepsilon$, y, $\phi$/. For both languages, in all these combinations, F1 values remained rather steady along the syllable. In the case of /o, u/ very likely the F2 difference lead to a variety of perceptions of the original /l/. For example in Ilul, French subjects reported some identifications of /l/ as a vowel, mainly /y/. Our observations reinforce the importance of F1 as a relevant cue for /l/, and the incidence of the relative distance between formants frequencies of both components.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3
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• pp.18-25
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• 1997

This study describes a modified preemphasis formula, what we call energy-dependent preemphasis(EDP). This uses the normalized short-term energy of speech signal, with the assumption that the source characteristics of the glottal pulses and the radiation characteristics of the lips are approximately proportional to the energy of speech signal. Using this method, speech analyses, such as AR spectrum estimation, formant detection, are performed for nonstationary starting parts of 5 Korean single vowels. The results are compared with the conventional two preemphasis methods. We found that the proposed preemphasis gave enhanced spectral shapes and more accurate formant frequencies and avoided overlapping phenomenon of adjacent two formants.

• Speech Sciences
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• v.7 no.2
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• pp.51-70
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• 2000

Twenty normal and 20 severe-to-profound hearing-impaired subjects participated in the present study. The two groups are matched by their chronological age. Each subject made a recording of three vowels of /i/, /a/, and /u/, and nine $VC_{plosive}V$ (hereafter, VCV) disyllables of /epe/, /ep'e/, /$ep^{h}e$/, /ete/, /et'e/, /$et^{h}e$/, /eke/, /ek'e/, and /$ek^{h}e$/, each five times. Formant frequencies of $F_1,\;F_2,\;and\;F_3$ were measured for the three vowels and six measures were made for the nine disyllables. The six measures were (1) the total duration of the disyllable, (2) the duration of the first vowel, (3) the duration of the closed period, (4) the ratio of the first vowel over the first vowel plus the closure period of the consonant, (5) the duration of the aspiration, and (6) the duration of the second vowel. Results shows that the three formants and each of the measures were significantly different between the two groups of subjects.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.21-27
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• 1997

Total laryngectomy has become an usual treatment for any advanced carcinoma of the laynx, but most patients who have undergone total laryngectomy have shown permanant disability in voice production. I compared the first three formant frequencies estimated from MRI to those measured directly from speech data of the T-E patients and the normal. It was to estimate the accuracy of MRI and to compare the vocal tract shape of the normal to T-E patients. The obtained results were as follows : 1. The middle sagittle section of the MRI represents vocal tract well during pnonation. The vocal tract shape of the T-E shunt patients are lack of pharyngeal space and superior space of the glottis. 2. The length of the normal subject's vocal tract is 17 cm. For the T-E shunt patients, the length from lip to shunt opening is 17.5 cm in case 1, and 18.5 cm in case 2. That of the true resonante chamber is 13 cm and 13.5 cm for each case respectively. 3. T-E shunt patients phonated strained voice. The intensity of the higher formant frequency decreased especially in /o/, /u/. 4. The vocal tract is shortened during the phonation by T-E shunt patients. In case of /e/ and /i/, front cavities are constricted while back cavities are shortened. 5. The pseudoglottis of the T-E shunt patients is located at $14{\sim}15\;cm$ below from lips.

• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.19-25
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• 2021

It has been widely recognized that there are two varieties of lateral liquid /l/, which are light /l/ (a non-velarized allophone) and dark /l/ (a velarized allophone). However, this categorical view has been challenged in recent studies, both on articulatory and acoustic aspects. The purpose of this study is to investigate whether to consider /l/ velarization as a continuum in American English and provide supporting data. A spontaneous American English speech database called the Buckeye Speech Corpus was used for the material. The formant frequencies of /l/ in each syllable position were measured and analyzed statistically. The formant frequencies of /l/ in each syllable position, especially F2 values, were significantly different from each other. The results showed that there were other significantly different varieties of /l/ in American English, which support the continuum view on /l/ velarization. Regarding the effect of the adjacent vowel, the backness of the adjacent vowels was shown to affect the degree of /l/ velarization, regardless of the syllable position of the lateral liquid. This result will help provide a solid ground for the continuum view.