• 대한후두음성언어의학회지
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• 제11권1호
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• pp.104-112
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• 2000

An evaluation of voice disorder has two methods. One is a perceptual analysis and the other is an acoustic analysis. All of these methods are just focused on sustained vowel. The analysis of conversational speech levels in voice disorder has not been achieved enough. The purpose of the present study is to compare two syllable words and sustained vowel in the vocal polyp patients and normal male speakers and to be applied on the vocal assessment and the voice therapy as a basic data. fifteen male patients with vocal polyp were the subject group. Fifteen healthy male were the control group for this study. The voices of the subject and control group, saved in MDVP of CSL were analyzed by its own analysis program. As a results, in subject group, the voice qualities between the vowel following lenis stop and the sustained vowel had no differences, and the voice qualities were different significantly between the vowel following heavily aspirated stop and the sustained vowel. In the control group the vowel fllowing stops and sustained vowel had also many differences in their voice quality, especially significant between the vowel following glottal stop and e sustained vowel.

• 한국지능시스템학회논문지
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• 제17권7호
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• pp.957-963
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• 2007

본 연구에서는 비선형 지속 모음 모델링을 위한 최소 제곱 서포트 벡터 회귀 기반 비선형 자귀회귀 방법을 소개하고 분석하였다. 비주기적인 파형 특성을 갖는 양성 후두 질환자 43명의 지속 모음을 대상으로 한 실험에서 제안된 비선형 합성기는 거의 완벽하게 혼란한 지속 모음을 생성하고 선형 예측 코딩은 할 수 없는 주파수 변동과 같은 자연스러운 음의 특성 또한 보존할 수 있었다. 하지만 일부 모음의 합성 결과 실제 원음과 다른 차이점을 보였다. 이러한 결과들은 단일 밴드 모델이 음의 고주파 성분을 조정, 분해 못하기 때문에 발생한 것이라 가정된다. 그러므로 웨이블릿 필터 뱅크를 이용한 멀티 밴드 모델을 단일 밴드 모델과 대치하여 실험을 수행한 결과 향상된 안정성을 보였다. 결과적으로 최소 제곱 서포트 벡터 회귀 기반 비선형 자귀회귀 방법은 성공적으로 원음에 가까운 합성음을 생성할 수 있다는 것을 확인 할 수 있었다.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.269-274
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• 2017

본 논문은 임상에서 음성장애 환자의 객관적 음성 분석 대상으로 주로 쓰이는 모음연장 발성이 분석하는 구간에 따라 어떠한 음향학적 차이를 보이는지 밝히고자 하였다. 본 연구에서는 성대결절 환자 17명의 /아/ 모음연장 발성을 시작, 중간, 끝 구간으로 편집하여 MDVP를 통해 각 구간의 jitter, shimmer, NHR을 산출하였고, 비교를 위하여 정상 음성 집단 12명의 음성도 분석하였다. 산출 결과는 R 통계프로그램을 활용하여 Fridman test와 사후 검정을 실시하였다. 음성장애 환자집단은 모음연장 발성의 끝 구간이 중간 구간에 비해 jitter, shimmer, NHR 값이 모두 유의하게 높은 것으로 나타났다. 또한, 발성의 시작 구간은 중간 구간에 비해 세 파라미터 모두에서 높게 산출됐지만 유의한 차이는 없었다. 반면, 정상 집단은 발성의 시작, 중간, 끝 모든 구간에서 유의한 차이가 없었다. 모음연장 발성은 구간에 따라 음향학적 파라미터의 분석 결과가 다르고 발성 끝 구간에서 중간 구간보다 유의하게 음성이 불안정해지는 것으로 나타났다. 이러한 결론은 임상 현장에서 모음연장 발성의 분석 구간 선택과 결과 해석에 유용하게 활용될 수 있을 것이다.

• 한국음향학회지
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• 제11권1호
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• pp.35-41
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• 1992

지속적으로 발성한 모음에 대해 각 화자의 특징을 나타내는 벡터양자화 코드북을 만들고 이를 이용해 화자를 인식하는 방법을 제안하고 실험하였다. 특히 벡터로는 모음 /이/로 부터 각각의 피치 주기에 대해 얻어진 선형예측계수를 사용하였으며, 코드북의 크기는 4가 적절함을 실험적으로 보였다. 인식실험에서, 학습에 사용된 데이타를 이용했을 경우에는 99.4%의 인식율을 보였으며, 학습에 사용되지 않은 50개의 피치 주기를 포함하는 음성신호로 부터는 89.4%의 인식율을 보였다.

• 대한후두음성언어의학회지
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• 제26권2호
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• pp.117-121
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• 2015

Background : Cepstral analysis which is obtained from Fourier transformation of spectrum has been known to be effective indicator to analyze the voice disorder. To evaluate the voice disorder, phonation of sustained vowel /a/ sound or continuous speech have been used but the former was limited to capture hoarseness properly. This study is aimed to compare the effectiveness in analysis of cepstrum between the sustained vowel /a/ sound and continuous speech. Methods : From March 2012 to December 2014, total 72 patients was enrolled in this study, including 24 unilateral vocal cord palsy, vocal nodule and vocal polyp patients, respectively. The entire patient evaluated their voice quality by VHI (Voice Handicap Index) before and after treatment. Phonation of sustained vowel /a/ sample and continuous speech using the first sentence of autumn paragraph was subjected by cepstral analysis and compare the pre-treatment group and post-treatment group. Results : The measured values of pre and post treatment in CPP-a (cepstral peak prominence in /a/ vowel sound) was 13.80, 13.91 in vocal cord palsy, 16.62, 17.99 in vocal cord nodule, 14.19, 18.50 in vocal cord polyp respectively. Values of CPP-s (cepstral peak prominence in text-based speech) in pre and post treatment was 11.11, 12.09 in vocal cord palsy, 12.11, 14.09 in vocal cord nodule, 12.63, 14.17 in vocal cord polyp. All 72 patients showed subjective improvement in VHI after treatment. CPP-a showed statistical improvement only in vocal polyp group, but CPP-s showed statistical improvement in all three groups (p<0.05). Conclusion : In analysis of cepstrum, text-based analysis is more representative in voice disorder than vowel sound speech. So when the acoustic analysis of voice by cepstrum, both phonation of sustained vowel /a/ sound and text based speech should be performed to obtain more accurate result.

• 말소리와 음성과학
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• 제8권2호
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• pp.73-80
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• 2016

The purpose of this study was to analyze perceptual and spectral/cepstral measurements in patients with adductor spasmodic dysphonia(ADSD). Sixty participants with gender and age matched individuals(30 ADSD and 30 controls) were recorded in reading a sentence and sustained the vowel /a/. Acoustic data were analyzed acoustically by measuring CPP, L/H ratio, mean CPP F0 and CSID, and auditory-perceptual ratings were measured using GRBAS. The main results can be summarized as below: (a) the CSID for the connected speech was significantly higher than for the sustained vowel (b) the G, R and S for the connected speech were significantly higher than for the sustained vowel (c) Spectral/cepstral parameters were significantly correlated with the perceptual parameters, and (d) the ROC analysis showed that the threshold of 13.491 for the CSID achieved a good classification for ADSD, with 86.7% sensitivity and 96.7% specificity. Spectral and cepstral analysis for the connected speech is especially meaningful on cases where perceptual analysis and clinical evaluation alone are insufficient.

• 말소리와 음성과학
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• 제1권3호
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• pp.65-72
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• 2009

Formant values are the most important acoustic correlates of English vowels. Classical studies on English vowels reported the first three formant values measured at a single timepoint on a sustained vowel segment. However, many recent studies revealed that partial onset or offset segments with information of dynamic spectral changes may contribute to the exact identification of English vowels with an accuracy almost comparable to that by the whole vowel segment or word. The purpose of this study was to examine formant trajectories of nine English vowels collected by Hillenbrand et al.(1995). Acoustic analysis was systematically made by a Praat script at six equidistant timepoints over the vowel segment. Results showed that the first formant trajectories played an important role in distinguishing each vowel within the front- or back-vowel groups. The second formant trajectories of the back vowels varied more drastically than those of the front vowels. The third formant value was similar except the high vowel /i/. From the vowel space on F1 by F2 axes, the formant trajectories of each vowel clearly showed a transition toward the locus of the following consonant /d/. Other acoustic data revealed that there were some vowel inherent duration or pitch values. From this study we can conclude that the dynamic spectral changes are very important in specifying acoustic characteristics of the English vowels. Further studies on vowels and diphthongs in different contexts are desirable.

• 대한음성학회지:말소리
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• 제57호
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• pp.73-84
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• 2006

The purpose of this study was to explore the acoustic characteristics of sexy voice. In this study, we measured acoustic parameters (fundamental frequency, jitter, shimmer, and nasalance) of a sustained vowel sound produced by 40 actors (20 males and 20 females) and 40 non-actors (20 males and 20 females). Digital audio recordings were made in the sustained vowel |a| for acoustic analyses using Praat (version 4.1.9) and Nasal View (version 4.5). Twenty voice pathologists participated in the listening experiment and judged the degree of sexiness on a 7-point scale. The results showed that fundamental frequency, shimmer and nasalance had significant differences between actors and non-actors. The acoustic parameters of sexy voice matched perceptual aspects of a previous study: Low fundamental frequency-low pitch and high shimmer-husky voice. On the other hand, the nasalance score did not match that of the previous study: Decreased nasalance had a higher score on sexiness scale judged by the listeners. It would be desirable to study the voice quality by analyzing and controlling more acoustic and auditory parameters for practical applications in the future.

• 말소리와 음성과학
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• 제10권4호
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• pp.67-76
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• 2018

This study was performed to investigate acoustic characteristics of sustained vowels produced by Seoul Korean speakers. For this study, three hundred nine healthy adults were chosen as participants from Korean Standard Speech Database. These subjects were divided into five chronological age groups (20s, 30s, 40s, 50s, 60-70s) and two gender groups (male and female). Fundamental frequency (f0), jitter, shimmer, and NHR (noise-to-harmonics ratio) was measured with 8 Korean vowels (/ɑ/, /æ/, /ʌ/, /e/, /o/, /u/, /ɯ/, /i/) by using Praat. The results showed that the vowel type significantly affected all acoustic parameters. Gender affected f0, jitter, and NHR significantly. The mean female speakers' f0 was greater than the males', and the mean jitter and NHR of male speakers was greater than the females'. Moreover, age affected shimmer and NHR significantly; in particular, the shimmer and NHR of elderly speakers was greater than the young speakers.

• 대한후두음성언어의학회지
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• 제11권1호
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• pp.76-80
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• 2000

Tongue-tip trill is a sound made by the tongue tip making contract with the alveolar ridge and oscillating rapidly as sound is produced. It is an exercise used by many singers to warm up the voice and used as one of the methods of voice rehabilitation for patients who have the vocal folds scarred postoperatively and also who present with a variety of disorders, particularly hypofunction and presbyphonia. We intended to investigate the mucosal vibration of the true vocal folds on tongue-tip trill by electroglottography and to find e effective methods of tongue-tip trill. One adult male volunteer participated. Spectrography and electroglottography were checked repeatedly 15 times, more than 5 second in each times, at same pitch, in three conditions of phonation : sustained /a/ vowel, anterior trill in which tongue-tip vibrated at anterior portion of alveolar ridge just behind the anterior tooth, and posterior trill in which at palatal crest behind the transverse palatine fold We measured the first and second formant to determine indirectly the position of tongue and calculated speed quotient and the ratio of closing phase to closed phase. Speed quotients of posterior trill were higher than sustained /a/ vowel and anterior trill in 14 times. The ratio of closing phase to dosed phase of posterior trill were lower than the others in 14 times. Mucosa of true vocal folds is vibrated more effectively on posterior trill rather than sustained /a/ vowel and anterior trill. So, when tongue-tip trill is used as a method of voice rehabilitation, we suggest that posterior trill is better in producing effective mucosal vibration