• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.962-977
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• 2019

The human voice is a convenient method of information transfer between different objects such as between men, men and machine, between machines. The development of information and communication technology, the voice has been able to transfer farther than before. The way to communicate, it is to convert the voice to another form, transmit it, and then reconvert it back to sound. In such a communication process, a vocoder is a method of converting and re-converting a voice and sound. The CELP (Code-Excited Linear Prediction) type vocoder, one of the voice codecs, is adapted as a standard codec since it provides high quality sound even though its transmission speed is relatively low. The EVRC (Enhanced Variable Rate CODEC) and QCELP (Qualcomm Code-Excited Linear Prediction), variable bit rate vocoders, are used for mobile phones in 3G environment. For the real-time implementation of a vocoder, the reduction of sound quality is a typical problem. To improve the sound quality, that is important to know the size and shape of noise. In the existing sound quality improvement method, the voice activated is detected or used, or statistical methods are used by the large mount of data. However, there is a disadvantage in that no noise can be detected, when there is a continuous signal or when a change in noise is large.This paper focused on finding a better way to decrease the reduction of sound quality in lower bit transmission environments. Based on simulation results, this study proposed a preprocessor application that estimates the SNR (Signal to Noise Ratio) using the spectral SNR estimation method. The SNR estimation method adopted the IMBE (Improved Multi-Band Excitation) instead of using the SNR, which is a continuous speech signal. Finally, this application improves the quality of the vocoder by enhancing sound quality adaptively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.1
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• pp.28-30
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• 2008

The problem of voice restoration after total laryngectomy has existed ever since Billroth's first total laryngectomy in 1873. Since then, all the efforts to restore the voice was tried to divert the tracheal air to the pharynx to produce voice, which became the tracheo-esophageal shunt voice currently used. With the intact pharyngoesophagus, however, there are two basic options for speech rehabilitation : the artificial larynx and esophageal voice. The artificial larynx is an electrically driven buzzer or a sound transducer and its most common type is placed against a supple point on patient's neck and introduces a mechanical sound into the tissues and air spaces of the neck. This sound, emanating form the mouth, is articulated by the intact structures of the remaining vocal tract as understandable speech. Esophageal voice is a commonly recommended method for alaryngeal speech rehabilitation, which can be successfully done by regurgitating the air stored in the esophagus. Successful esophageal voice is preferable to the artificial larynx but, most patients usually adapt only one of those methods according to their needs and feasibility to learn.

• Journal of the HCI Society of Korea
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• v.11 no.2
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• pp.15-22
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• 2016

The ways to interact with digital appliances are becoming more diverse. Users can control appliances using a remote control and a touch-screen, and appliances can send users feedback through various ways such as sound, voice, and visual signals. However, there is little research on how to define which output method to use for providing feedback according to the user' input method. In this study, we designed an experimental study that seeks to identify how to appropriately match the output method - voice and sound - based on the user input - voice and button. We made four types of interaction with two kinds input methods and two kinds of output methods. For the four interaction types, we compared the usability, perceived satisfaction, preference and suitability. Results reveals that the output method affects the ease of use and perceived satisfaction of the input method. The voice input method with sound feedback was evaluated more satisfying than with the voice feedback. However, the keying input method with voice feedback was evaluated more satisfying than with sound feedback. The keying input method was more dependent on the output method than the voice input method. We also found that the feedback method of appliances determines the perceived appropriateness of the interaction.

• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.9-17
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• 2021

Voice onset time (VOT) is known to be a primary acoustic cue that differentiates voiced from voiceless stops in the world's languages. While much attention has been given to the sound change of Korean stops, little attention has been given to that of English stops. This study examines VOT of stop consonants as produced by English speakers in comparison to Korean speakers to see whether there is any VOT change for English stops and how the effects of stop, place, gender, and individual on VOT differ cross-linguistically. A total of 24 native speakers (11 Americans and 13 Koreans) participated in this experiment. The results showed that, for Korean, the VOT merger of lax and aspirated stops was replicated, and, for English, voiced stops became initially devoiced and voiceless stops became heavily aspirated. English voiceless stops became longer in VOT than Korean counterparts. The results suggest that, similar to Korean stops, English stops may also undergo a sound change. Since it is the first study to be revealed, more convincing evidence is necessary.

• Phonetics and Speech Sciences
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• v.4 no.2
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• pp.95-104
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• 2012

Thyroidectomy patients may have vocal paralysis or paresis, resulting in a breathy voice. The aim of this study was to investigate the aerodynamic and acoustic characteristics of a breathy voice in thyroidectomy patients. Thirty-five subjects who have vocal paralysis after thyroidectomy participated in this study. According to perceptual judgements by three speech pathologists and one phonetic scholar, subjects were divided into two groups: breathy voice group (n = 21) and non-breathy voice group (n = 14). Aerodynamic analysis was conducted by three tasks (Voicing Efficiency, Maximum Sustained Phonation, Vital Capacity) and acoustic analysis was measured during Maximum Sustained Phonation task. The breathy voice group had significantly higher subglottal pressure and more pathological voice characteristics than the non breathy voice group. Showing 94.1% classification accuracy in result logistic regression of aerodynamic analysis, the predictor parameters for breathiness were maximum sound pressure level, sound pressure level range, phonation time of Maximum Sustained Phonation task and Pitch range, peak air pressure, and mean peak air pressure of Voicing Efficiency task. Classification accuracy of acoustic logistic regression was 88.6%, and five frequency perturbation parameters were shown as predictors. Vocal paralysis creates air turbulence at the glottis. It fluctuates frequency-related parameters and increases aspiration in high frequency areas. These changes determine perceptual breathiness.

• Journal of Sasang Constitution and Immune Medicine
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• v.16 no.1
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• pp.53-60
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• 2004

Purpose This study is to find the characteristics of voice quality based on the classifying the sound characteristics and B.M.I. by Sasang Constitution. Methods To make the notion of the consensus of Sasang Constitution's Voice, classification into 4 categories was made: clear/hoarse, high/low, powerful/powerless, fast/slow. Result The voice quality of Soyangin group was classified as powerful and fast, and that of Taeumin group was classified as powerful and hoarse and low, and that of Soeumin group was classified as powerless and clear. The mean B.M.I. of Soeumin group was classified as 21.4, and that of Taeumin group was classified as 26.3. Conclusion 1. Taeumin was significantly high compared with Soeumin in B.M.I. 2. It can be classified as Taeumin when B.M.I. is high(26.3). 3. It can be classified as Soeumin when B.M.I. is low(21.4). 4. The voice quality of Soyangin group was classified as clear and fast, or strong and clear, and that of Taeumin group as powerful and hoarse, and that of Soeumin group as powerless and low.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.223-228
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• 2010

This study investigated the closed quotient and other voice quality parameters using electroglottography (EGG) in sustaining the vowel /a/ and reading a sentence at the comfortable pitch and loudness in healthy Korean adults. Seventy two healthy adults (36 men, 36 women) aged 20~40 years were included in the study. The tasks were recorded and analyzed using Lx Speech Studio. In vowel sustaining task, closed quotient (Qx), fundamental frequency (Fx), sound pressure level (SPL), Jitter, and Shimmer were measured. In sentence reading task, closed quotient (DQx), fundamental frequency (DFx), and sound pressure level (DAx) were measured. The sex effects were observed on Qx, Fx, Shimmer, DQx, and DFx. Men had significantly higher Qx and DQx than women, but had significantly lower Shimmer than women. However, there was no sex effect on Jitter. The task effects on Qx and SPL as well as DQx and DAx were also assessed. Qx and SPL were significantly higher than DQx and DAx in both gender. This study showed that the closed quotients in both vowel sustaining and sentence reading tasks were significantly related to other voice quality parameters. Therefore, clinicians and researchers should describe the voice quality parameters like fundamental frequency, sound pressure level, Jitter, Shimmer, and so on when reporting closed quotients using EGG.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1659-1666
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• 2018

When the input sound is mixed voice and sound, it can be seen that the voice recognition rate is lowered due to the noise, and the speech recognition rate is improved by improving the MEMS device which is the H / W device in order to overcome the S/W processing limit. The MEMS microphone device is a device for inputting voice and is implemented in various shapes and used. Conventional MEMS microphones generally exhibit excellent performance, but in a special environment such as noise, there is a problem that the processing performance is deteriorated due to a mixture of voice and sound. To overcome these problems, we developed a newly designed MEMS device that can detect the voice characteristics of the initial input device.

• Proceedings of the KSLP Conference
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• 1995.11a
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• pp.128-136
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• 1995

Diagnostic evaluation for voice disorders requires a multidimensional approach : physiological examination of the larynx and the vocal tract, aerodynamic studies, examinations of vocal fold vibrations, psychoacoustic evaluations, acoustical analyses, and so on. Previous studies with the use of a computer system suggested that the acoustic evaluation is quite promising for differentiating some causative diseases of voice disorders(Hiki et al., 1975a, b, 1976 ; Kakita et al., 1980). However, a well-equipped computer system for acoustic analysis is very expensive and not available in most voice clinics. A sound spectrograph is available in many voice clinics. (omitted)

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.291-305
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• 2020

Purpose : The duration of speech segments reflects children's speech motor development. The purpose of this study was to determine whether segmental sound and word duration varies by age among preschool children. Methods : A total of 60 children aged 4~5 years participated in this study. Participants took the picture-naming test to produce single-word speech data. The duration of the consonant at the initial position of the word and the final position of the word, the voice onset time of plosive, the duration of the vowel following the initial consonant, and the duration of the word were measured. Results : As age increased, the duration of the initial consonant, the duration of the word, and the voice onset time decreased significantly. The main effects of age, manner of articulation, and place of articulation on the duration of the initial consonant were significant. The duration of consonants in the nasal sound and plosives and the duration of bilabial and alveolar sound differed significantly between groups. The main effects of age and vocal type on voice onset time were significant. The main effect of age on the duration of the consonant in the final position of word and on the duration of the vowel were not statistically significant. Conclusion : The results of this study showed that the duration of segmental sound and the word were associated with speech development between 4 and 5 years old. Accordingly, duration of the segmental sound and the word may serve as an acoustic cue as they reflect speech development and speech motor control maturity.