• 말소리와 음성과학
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• 제7권1호
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• pp.21-26
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• 2015

The aim of this study is to synthesize pathological breathy voice and to make a cepstral peak prominence (CPP) table following breathiness ranks by cepstral analysis to supplement reliability of the perceptual auditory judgment task. KlattGrid synthesizer included in Praat was used. Synthesis parameters consist of two groups, i.e., constants and variables. Constant parameters are pitch, amplitude, flutter, open phase, oral formant and bandwidth. Variable parameters are breathiness (BR), aspiration amplitude (AH), and spectral tilt (TL). Five hundred sixty samples of synthetic breathy vowel /a/ for male were created. Three raters participated in ranking of the breathiness. 217 were proved to be inadequate samples from perceptual judgment and cepstral analysis. Finally, 343 samples were selected. These CPP values and other related parameters from cepstral analysis are classified under four breathiness ranks (B0~B3). The mean and standard deviation of CPP is $16.10{\pm}1.15$ dB(B0), $13.68{\pm}1.34$ dB(B1), $10.97{\pm}1.41$ dB(B2), and $3.03{\pm}4.07$ dB(B3). The value of CPP decreases toward the severe group of breathiness because there is a lot of noise and a small quantity of harmonics.

• 말소리와 음성과학
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• 제12권4호
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• pp.91-98
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• 2020

근긴장성 발성장애(cepstral peak prominence, MTD) 환자의 모음 발성과 문장읽기 과제를 켑스트럼 기반 변수를 이용하여 분석하였으며 음성장애 환자의 GRBAS청지각적 특성과 음향학적 특성의 상관관계를 살펴보고, 랜덤포레스트 머신러닝 분류 알고리듬을 이용한 MTD 감별 진단 가능성을 논의하였다. 내원 시 MTD로 진단받은 여성 36명과 정상음성을 사용하는 여성 36명이 연구에 참여했으며, 수집한 음성샘플은 ADSVTM를 사용하여 분석하였다. 연구 결과, 음향학적 측정치 중 MTD의 CSID(cepstral spectral index of dysphonia)는 대조군보다 높았으며, CPP(cepstral peak prominence), CPP_Fo 값이 대조군보다 유의하게 낮았다. 이는 모음 발성과 읽기 과제에서 모두 동일하게 나타났다. MTD 환자의 음질 특성은 전반적인 음성중증도(G)가 가장 두드러졌으며, 조조성(R), 기식성(B), 노력성(S)순으로 음성 특성을 보였다. 이 특성이 높아질수록 CPP가 감소하는 부적 상관을 보이고, CSID는 증가하는 정적 상관이 관찰되었다. 켑스트럴 변수 중 모음과 문장읽기과제 모두에서 집단간 유의한 차이를 보여준 CPP와 CPP_F0를 이용하여 MTD와 대조군의 음성분류를 시도하였다. 머신러닝 알고리듬인 랜덤포레스트로 모델링한 결과 문장읽기 과제에서 모음연장발성보다 조금 더 높은 분류 정확도(83.3%)가 나왔으며, 모음 발성과 문장 읽기 과제 모두에서 CPP변수가 더 중심적 역할을 수행하였음을 알 수 있었다.

• 말소리와 음성과학
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• 제4권2호
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• pp.89-94
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• 2012

The aim of this study is to investigate the usefulness of the parameter CPP (cepstral peak prominence) and LTAS (long term average spectrum) band energy for an analysis of breathy voice with vocal fold paralysis. Thirty-four female subjects who have vocal paralysis after thyroidectomy participated in this study. According to the 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 = 13). Maximum sustained phonation task was measured for acoustic analysis. CPP-related (i.e. mean F0, mean CPP, and mean CPPs) and LTAS-related (i.e. minimum, maximum, and mean) parameters were used. Independent samples t-test was conducted. Regarding CPP, there are significant differences in mean CPP and mean CPPs between groups. The values of mean CPP and CPPs in the non-breathy voice group are higher than those in the breathy voice group. The CPP could be regarded as the useful parameter for breathy voice analysis in the clinic. When it comes to LTAS, energy from 0 to 2 kHz are significantly different between groups. The minimum value of non-breathy group is lower than that of breathy group, whereas the maximum value of non-breathy group is higher. The frequency band below 2 kHz seems to be related to breathy voice.

• 대한후두음성언어의학회지
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• 제28권2호
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• pp.84-88
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• 2017

Background and Objectives : The purpose of this study was to compare the usefulness of Cepstral peak prominence (CPP) with parameter of Multiple Dimensional Voice Program (MDVP) in evaluating unilateral vocal fold paraylsis patients with subjective voice impairment. Materials and Methods : From July 2014 to August 2016, 37 patients with unilateral vocal fold paralysis who had been diagnosed with unilateral vocal fold paralysis and had received two or more voice tests before and after the diagnosis were evaluated for maximum phonation time (MPT), MDVP and CPP. Respectively. Voice tests were performed with short vowel /a/ and paragraph reading. Results : The CPP-a (CPP with vowel /a/) and CPP-s (CPP with paragraph reading) of the Cepstrum were statistically negatively correlated with G, R, B, and A before the voice therapy. Jitter, Shimmer, and NHR of MDVP were positively correlated with G, R, B. Jitter, Shimmer, and NHR of the MDVP were significantly correlated with the Cepstrum index. G, B, A and CPP-a and CPP-s showed a statistically significant negative correlation and a somewhat higher correlation coefficient between 0.5 and 0.78. On the other hand, in MDVP index, there was a positive correlation with G and B only with Jitter of 0.4. Conclusion : CPP can be an important evaluation tool in the evaluation of speech in the unilateral vocal cord paralysis when speech energy changes or the cycle is not constant during speech.

• 대한음성언어의학회:학술대회논문집
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• 대한음성언어학회 2017년도 제46차 춘계학술대회
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• pp.91-91
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• 2017

• 한국음향학회지
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• 제42권4호
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• pp.298-303
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• 2023

본 연구는 장애음성의 평가에 사용되는 연속발화과제로서 유성음 문장의 임상적 유용성을 알아보기 위한 것이다. 이를 위해, 모음연장발성과제의 음향학적 측정치인 주파수 변동률(jitter percent, jitter), 진폭 변동률(shimmer percent, shimmer), 소음대배음비(Noise to Harmonic Ratio, NHR)와 유성음으로만 이루어진 연속발화과제의 음향학적 측정치로 캡스트럼 분석 측정치인 켑스트럼 피크 현저성(Cepstral Peak Prominence, CPP), 저주파수대고주파수 스펙트럼비(Low/High spectral ratio, L/H ratio)의 상관을 분석하였다. 음성장애 환자 65명을 대상으로 수집된 자료를 분석한 결과, 유성음 문장의 음향학적 측정치인 CPP와 모음연장발성의 측정치인 jitter(r = -.624, p = .000), shimmer (r = -.530, p = .000), NHR(r = -.469, p = .000) 간에 유의한 상관이 나타났다. 이는 유성음 문장의 캡스트럼 측정치가 '연속발화 과제의 변동률 기반 분석 불가능', '분석구간과 길이에 따른 결과차이' 등 언어재활 임상현장이 가지고 있는 장애음성의 음향학적 분석의 제한에 대한 대안으로 유용하게 사용될 수 있음을 시사한다.

• 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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• 제10권2호
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• pp.77-84
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• 2018

The purpose of this study is to examine the acoustic characteristics of Parkinsonian speech, with respect to different utterance conditions, by employing acoustic/auditory-perceptual analysis. The subjects of the study were 15 patients (M=7, F=8) with Parkinson's disease who were asked to read out sentences under different utterance conditions (clear/casual). The sentences read out by each subject were recorded, and the recorded speech was subjected to cepstrum and spectrum analysis using Analysis of Dysphonia in Speech and Voice (ADSV). Additionally, auditory-perceptual evaluation of the recorded speech was conducted with respect to breathiness and loudness. Results indicate that in the case of clear speech, there was a statistically significant increase in the cepstral peak prominence (CPP), and a decrease in the L/H ratio SD (ratio of low to high frequency spectral energy SD) and CPP F0 SD values. In the auditory-perceptual evaluation, a decrease in breathiness and an increase in loudness were noted. Furthermore, CPP was found to be highly correlated to breathiness and loudness. This provides objective evidence of the immediate usefulness of clear speech intervention in improving the voice quality of Parkinsonian speech.

• 말소리와 음성과학
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• 제15권4호
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• pp.45-51
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• 2023

나이가 들면서 발생하는 음성 문제는 사회적, 정서적으로 영향을 미칠 수 있으며, 나아가 고립감과 우울증으로 이어질 수 있다. 이에 본 연구에서는 노화로 인한 음향학적 특성 변화를 음질과 구어 유창성의 변화를 알아보고자 한다. 이를 위해 노년층 남성 20명과 청년층 남성 20명이 산출한 연장발성과 구절 읽기 과제를 녹음하여 분석하였다. 음질 분석 변수로 기본주파수(F0), 주기 변동률(jitter), 진폭 변동률(shimmer), 켑스트럼 정점(cepstral peak prominence, CPP) 값을 분석하였으며 구어 유창성 분석 변수로는 평균 음절 길이(average syllable duration, ASD), 조음 속도(articulation rate, AR), 구어 속도(SR)를 분석하였다. 연구결과, 음질 측정에서 노년층의 경우 F0가 높게 나타났으며 jitter, shimmer, CPP의 결과값을 통해 음질이 저하된 것으로 나타났다. 구어 유창성 분석 결과, 노년층은 ASD, AR, SR의 결과값을 통해 느리게 발화하는 것으로 나타났다. 음질과 구어유창성 간 상관관계 분석 결과, shimmer와 CPP 값과 각각 ASD와 SR에서 높은 상관관계가 나타났다. 본 연구결과를 통해 노화에 따른 음성과 구어 유창성 변화를 조기에 발견하고 이에 대한 적절한 훈련법을 제공할 수 있을 것으로 기대된다.

• 말소리와 음성과학
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• 제5권4호
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• pp.33-41
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• 2013

This study investigated the perceptual and cepstral/spectral characteristics of phonation and their relationships in dysarthria in connected speech. Twenty-two participants were divided into two groups; the eleven dysarthric speakers were paired with matching age and gender healthy control participants. A perceptual evaluation was performed by three speech pathologists using the GRBAS scale to measure the cepstrual/spectral characteristics of phonation between the two groups' connected speech. Correlations showed dysarthric speakers scored significantly worse (with a higher rating) with severities in G (overall dysphonia grade), B (breathiness), and S (strain), while the smoothed prominence of the cepstral peak (CPPs) was significantly lower. The CPPs were significantly correlated with the perceptual ratings, including G, B, and S. The utility of CPPs is supported by its high relationship with perceptually rated dysphonia severity in dysarthric speakers. The receiver operating characteristic (ROC) analysis showed that the threshold of 5.08 dB for the CPPs achieved a good classification for dysarthria, with 63.6% sensitivity and the perfect specificity (100%). Those results indicate the CPPs reliably distinguished between healthy controls and dysarthric speakers. However, the CPP frequency (CPP F0) and low-high spectral ratio (L/H ratio) were not significantly different between the two groups.