• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.30 no.2
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• pp.107-111
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• 2019

Background and Objectives Idiopathic unilateral vocal fold paralysis (IVFP) is believed to be due to inflammation and edema of the recurrent laryngeal nerve caused by viral diseases such as upper respiratory tract infections. Corticosteroid has a potent anti-inflammatory action which should minimize nerve damage. The purpose of this study was to investigate the effect of oral steroid therapy on IVFP. Materials and Method Study was performed for the IVFP patient from January 2012 to August 2017. Patient's dermography, direction and location of paralyzed vocal cords, history of hypertension, diabetes, cerebrovascular disease, and other underlying disease, smoking history, alcohol consumption and upper respiratory tract infection, and symptoms were investigated. Treatment was divided into three groups: the observation group, low-dose group, and high-dose group, and the recovery rate and time of vocal cord paralysis were analyzed in each group. Results Thirty-seven patients were enrolled in this study. There was no relationship between oral steroid use, dosage and recovery of vocal cord paralysis. Oral steroids showed a rapid recovery of vocal cord paralysis, but there was no statistically significant difference in the time of recovery of vocal palsy with or without steroids (p=0.673). In addition, there was no statistically significant difference in recovery rate between the period to start of treatment, presence of diabetes mellitus, and treatment modality, but the recovery rate was high in the group with upper respiratory tract infection history (p=0.041). Conclusion In IVFP, oral steroid therapy has no significant difference in time and extent of recovery compared to the case of spontaneous recovery.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.1
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• pp.1-8
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• 1982

Many researches on the parametric representation of speech ,signals using the adaptive linear prediction method have been studied for the past few years. In this paper, we used the LPC(Linear Predictive Coding)method to analyae the parameters of Korean vowels and by using those parameters we studied the affinity between every pair of Korean vowels. As a result of our study, it is found that each pair of Korean vowels that has a greater phonetic affinity also has a greater affinity of vocal tract parameters than other pairs.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.219-222
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• 2001

The human speech sounds are use to diagnosis in oriental medicine with ‘0-sung’theory. In general, human voice are sound waves which generated by phonation. Two major parts of phonation are vocal cords and vocal tract. The uniqueness of individual vocal sound depend on structure and usage of their vocal cords and tract. In the oriental medicine, “0-sung (5-tones)” has been used to classify constitution of human body In order to characterize the “0-sung”, their frequency characteristics are investigated, and a principal frequency component is extracted. Then, the principal component is applied to classify sounds into “0-sung.”

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.5 no.1
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• pp.44-58
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• 1994

The formants of the 9 Korean standard vowels(which used by the average people of Seoul, central-area of the Korean peninsula) were measured by analysis with the linear predictive coding(LPC) and fast Fourier transform(FFT). The author already had reported the constriction area for the Korean standard vowels, and with the existing data, the distance from glottis to the constriction area in the vocal tract of each vowel was newly measured with videovelopharyngograms and lateral Rontgenograms of the vocal tract. We correlated the formant frequencies with the distance from glottis to the constriction area of the vocal tract. Also we tried to correlate the formant frequencies with the position of tongue in the vocal tract which is divided into 2 categories : The position of tongue in oral cavity by the distance from imaginary palatal line to the highest point of tongue and the position in pharyngeal cavity by the distance from back of tongue to posterior pharyngeal wall. This study was performed with 10 adults(male : 5, female : 5) who spoke primary 9 Korean standard vowels. We had already reported that the Korean vowel [i], [e], $[{\varepsilon}]$ were articulated at hard palate level, [$\dot{+}$], [u] were at soft palate level, [$\wedge$] was at upper pharynx level and the [$\wedge$], [$\partial$], [a] in a previous article. Also we had noted that the significance of pharyngeal cavity in vowel articulation. From this study we have concluded that ; 1) The F$_1$ is related with the oral cavity articulated vowel [i, e, $\varepsilon$, $\dot{+}$, u]. 2) Within the oral cavity articulated vowel [i, e, $\varepsilon$, $\dot{+}$, u] and the upper pharynx articulated vowel [o], the F$_2$ is elevated when the diatance from glottis to the constriction area is longer. But within the lower pharynx articulated vowel [$\partial$, $\wedge$, a], the F$_2$ is elevated when the distance from glottis to the constriction area is shorter. 3) With the stronger tendency of back-vowel, the higher the elevation of the F$_1$ and F$_2$ frequencies. 4) The F$_3$ and F$_4$ showed no correaltion with the constriction area nor the position of tongue in the vocal tract 5) The parameter F$_2$- F$_1$, which is the difference between F$_2$ frequency and F$_1$ frequency showed an excellent indicator of differenciating the oral cavity articulated vowels from pharyngeal cavity articulated vowels. If the F$_2$-F$_1$ is less than about 600Hz which indicates the vowel is articulated in the pharyngeal cavity, and more than about 600Hz, which indicates that the vowel is articulated in the oral cavity.

• Proceedings of the KSLP Conference
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• 1998.11a
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• pp.201-207
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• 1998

현악기의 대표격 악기라고 할 수 있는 바이올린이나 기타는 소리(음원)를 만들어 내는 역할을 하는 줄(현)과 공명통이 합쳐져 있는 모양을 하고 있다. 활로 바이올린 줄은 긁거나 기타줄을 손으로 튕겨서 소리를 만들어 내면, 이 소리는 공명통을 울려서 크고 아름다운 소리가 발생되는 것이다. 사람의 목소리도 이러한 현악기와 비슷한 구조를 가지고 있어서, 두 개의 줄모양을 하고 있는 성대에서 성대음(glottal sound)을 만들어 내며 이 성대음이 성도(성도, vocal tract)를 통과하면서 여과(filtration) 되고 성도의 모양에 따른 특성에 따라 공명(resonance) 현상을 일으켜서 입술이나 콧구멍 바깥으로 방출되어 말소리(speech sound)를 만들어내는 것이다. (중략)

• Speech Sciences
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• v.7 no.3
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• pp.197-218
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• 2000

The vocal tract shapes were measured from tracheoesophageal speakers during the sustained phonation of five Korean vowels /u/, /o/, /a/, /e/, /i/ using magnetic resonance image(MRI). The subject's original vowel utterances with speech intelligibility and the synthesized vowels from MR images were analyzed. The results were as follows: (1) The vowels /a/, /e/, /i/ were perceived as the same sounds of actual subject's speech, but the vowels /o/ and /u/ were perceived as /$\partial$/ and strained /u/, respectively. (2) The synthesized vowels /a/ and /e/ from the MR images were perceived as the same sounds, but the vowels /u/, /o/, /i/ were perceived as different sounds. (3) The synthesized vowel by the expanded pharyngeal segment of 3 times in vowel /o/ was perceived as more natural than that of 2 times. The pharyngeal areas with varied sizes should be experimented to secure better speech production because the correct shapes of the vocal tract lead to distinct vowel production.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.773-778
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• 2009

This paper studied the training methods less affected by the emotional variation for the development of the robust speech recognition system. For this purpose, the effect of emotional variations on the speech signal were studied using speech database containing various emotions. The performance of the speech recognition system trained by using the speech signal containing no emotion is deteriorated if the test speech signal contains the emotions because of the emotional difference between the test and training data. In this study, it is observed that vocal tract length of the speaker is affected by the emotional variation and this effect is one of the reasons that makes the performance of the speech recognition system worse. In this paper, vocal tract normalization method is used to develop the robust speech recognition system for emotional variations. Experimental results from the isolated word recognition using HMM showed that the vocal tract normalization method reduced the error rate of the conventional recognition system by 41.9% when emotional test data was used.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.53-56
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• 2001

사람은 연령, 성별 등에 따라 성도(vocal tract), 성대(vocal cord, 혹은 vocal fold), 비강(nasal tract)등 발성기관의 차이가 있고, 이는 음성의 음색, 높낮이 등 음향 특성에 영향을 미치며, 시간이 지나감에 따라 변하는 특성을 가지고 있다. 예를 들어, 발성기관의 차이가 큰 남성과 여성은 동일한 단어를 발성하더라도 음향학적으로 매우 큰 차이를 보이며, 이러한 특성은 다른 문장 발성 시에도 음향학적으로 일정한 영향을 미치게 되므로 정적특성이라 한다. 본 논문에서는 이러한 정적특성 중 음성의 발성크기에 따른 Glottal Spectrum을 비교 $\cdot$분석 하고자 한다.

• Proceedings of the KSPS conference
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• 2003.05a
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• pp.141-144
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• 2003

In this paper, we compared formant frequency extraction algorithms with various conditions, and show their performances. The formant frequency is the resonance frequency which is decided by the vocal tract characteristics. It is related with phonemes, or characteristics of the physical condition of the vocal track. Since the speech signal is influenced by both the sound source and the vocal tract, it is difficult to calculate the exact formant frequencies. Many studies on the formant frequency extraction had been executed already Besides, any new formant frequency extraction algorithm is hardly found recently.

• Speech Sciences
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• v.10 no.2
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• pp.85-95
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• 2003

In speech signal processing, it is very important to detect the pitch exactly in speech recognition, synthesis and analysis. If we exactly pitch detect in speech signal, in the analysis, we can use the pitch to obtain properly the vocal tract parameter. It can be used to easily change or to maintain the naturalness and intelligibility of quality in speech synthesis and to eliminate the personality for speaker-independence in speech recognition. In this paper, we proposed a new pitch detection algorithm. First, positive center clipping is process by using the incline of speech in order to emphasize pitch period with a glottal component of removed vocal tract characteristic in time domain. And rough formant envelope is computed through peak-fitting spectrum of original speech signal infrequence domain. Using the roughed formant envelope, obtain the smoothed formant envelope through calculate the linear interpolation. As well get the flattened harmonics waveform with the algebra difference between spectrum of original speech signal and smoothed formant envelope. Inverse fast fourier transform (IFFT) compute this flattened harmonics. After all, we obtain Residual signal which is removed vocal tract element. The performance was compared with LPC and Cepstrum, ACF. Owing to this algorithm, we have obtained the pitch information improved the accuracy of pitch detection and gross error rate is reduced in voice speech region and in transition region of changing the phoneme.