• 음성과학
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• 제10권1호
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• pp.117-129
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• 2003

Many people suffer from various laryngeal diseases. Since we can notice voice change easily, acoustic analysis can be helpful to diagnose the diseases. Several attempts have been made to clarify the relation between the parameters and the state of sick vocal folds but any decisive parameters are not found yet. The purpose of this study was to select and develop those parameters useful for diagnosing and differentiating laryngeal diseases. We examined eight MDVP parameters, and two additional MFCC and LPC parameters obtained from the production of an open vowel by 252 subjects with or without laryngeal diseases. Using a statistical procedure through the artificial neural networks, we attempted to differentiate laryngeal disease groups. Results showed that the LPC parameters indicated the highest differentiating rate by the networks followed by the MFCC and the MDVP parameters. In addition, Jita, Shim and NHR among the MDVP parameters came out better parameters in diagnosing laryngeal diseases.

• 말소리와 음성과학
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• 제2권4호
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• pp.213-221
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• 2010

The number of North Korean refugees entering South Korea is continuously increasing. North Korean speakers show significant differences in vowel and consonant phonetics, length of vowels, and the rhythm and intonation of sentences. The object of this research was to examine the effectiveness of a speech intervention program for North Korean refugees using visual feedback through acoustical analysis for intonation. The subjects were three adults with no speech disabilities who had been in South Korea for less than five years. They had not received any prior treatment for inflection change. The program was set in a discourse situation and used Praat to evaluate intonation and provide visual feedback as demonstrating proper intonation changes through pitch contour. The results after intervention are as follows. First, intonation was significantly improved according to a 5-point subjective evaluation scale. Second, the pitch contour was similar to the contour of standard South Korean pronunciation. The subjects were very satisfied with this initial treatment and showed a high level of motivation. In subsequent study, the development of intervention and the comparison of interventions will be needed as well.

• 말소리와 음성과학
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• 제10권4호
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• pp.135-146
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• 2018

The Modified Voiced Lip Trill (MVoLT) training is a variant of voiced lip-till training characterized by increased loudness, lowered laryngeal position, and lip contact facilitated with fingers. The purpose of the current study was to assess the effect of the MVoLT training program on vocal changes of musical singing theater students. A total of 32 musical theater students (17 males and 15 females, age ranging from 18 to 29) participated in the study. For about three months, each participant was tutored using a systematic program focussing on the MVoLT training, accompanied by certain facilitating strategies. Pre- & post-training multi-dimensional vocal characteristics were assesed and compared. Results showed that cepstral peak prominence during vowel phonation increased after training, while its standard deviation and Cepstral Spectral Index of Dysphonia decreased. When an aerodynamic assessment was performed, maximum phonation time, subglottal pressure, mean airflow rate increased, while electroglottographic measures did not change. In addition, decreased psychometric measures, higher maximum pitch, and increased vocal range were noted after training. In conclusion, the MVoLT was proven to have a potential as an effective and safe training method for musical theater singing.

• 대한후두음성언어의학회지
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• 제33권3호
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• pp.142-155
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• 2022

Diagnosis using voice is non-invasive and can be implemented through various voice recording devices; therefore, it can be used as a screening or diagnostic assistant tool for laryngeal voice disease to help clinicians. The development of artificial intelligence algorithms, such as machine learning, led by the latest deep learning technology, began with a binary classification that distinguishes normal and pathological voices; consequently, it has contributed in improving the accuracy of multi-classification to classify various types of pathological voices. However, no conclusions that can be applied in the clinical field have yet been achieved. Most studies on pathological speech classification using speech have used the continuous short vowel /ah/, which is relatively easier than using continuous or running speech. However, continuous speech has the potential to derive more accurate results as additional information can be obtained from the change in the voice signal over time. In this review, explanations of terms related to artificial intelligence research, and the latest trends in machine learning and deep learning algorithms are reviewed; furthermore, the latest research results and limitations are introduced to provide future directions for researchers.

• 말소리와 음성과학
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• 제9권1호
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• pp.1-7
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• 2017

Previous studies have reported on the overlapping of $F_1$ and $F_2$ distribution for the vowels /o/ and /u/ produced by young Korean speakers of the Seoul dialect. It has been suggested that the overlapping of /o/ and /u/ occurs due to sound change. However, few studies have examined whether speech rate influences the overlapping of /o/ and /u/. On the other hand, previous studies have reported that the overlapping of /o/ and /u/ in syllable produced by male speakers is smaller than by female speakers. Few reports have investigated on the overlapping of the two vowels in read speech produced by male speakers. In the current study, we examined whether speech rates affect overlapping of /o/ and /u/ in read speech by male and female speakers. Read speech produced by twelve young adult native speakers of Seoul dialect were recorded in three speech rates. For female speakers, discriminant analysis showed that the discriminant rate became lower as the speech rate increases from slow to fast. Thus, this indicates that speech rate is one of the factors affecting the overlapping of /o/ and /u/. For male speakers, on the other hand, the discriminant rate was not correlated with speech rate, but the overlapping was larger than that of female speakers in read speech. Moreover, read speech by male speakers was less clear than by female speakers. This indicates that the overlapping may be related to unclear speech by sociolinguistic reasons for male speakers.

• 말소리와 음성과학
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• 제9권3호
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• pp.85-91
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• 2017

The present study aimed to investigate the changes of acoustic parameters of the aspirated voice in stroke patients. The eighty-eight subjects diagnosed with cerebro-vascular accident were divided into 32 penetration/aspiration (P/A) and 56 Non-P/A groups according to the videofluroscopic swallowing study (VFSS) results, and 26 control subjects participated. All subjects preformed VFSS and vowel /a/ was recorded three times pre- and post VFSS. Since the variation in the acoustic parameters within a single phonation has been observed, we proposed a delta formula for the acoustic parameters which can reflect the temporal changes of the each parameter in an utterance. We measured from the voice data eight acoustic parameters: fundamental frequency (F0), standard deviation of F0 (F0_SD), Jitter, relative average perturbation (RAP), Shimmer, amplitude perturbation quotient (APQ), harmonic to noise ration (HNR), noise to harmonic ratio (NHR). Then we found parameters which show the meaningful biggest temporal change in an utterance using the suggested delta parameter. Among them, the deltas of shimmer and APQ were significantly different pre- and post VFSS. These deltas of the P/A and the control group were increased after VFSS, while those of the Non-P/A group was descended. The variation patterns of the P/A and the control group were similar but the change width of the P/A group was larger. The large variations in an aspirated phonation of the P/A group are thought to be caused by irregular changes in air resistance due to residual food on the vocal cords.

• 한국전문물리치료학회지
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• 제16권2호
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• pp.16-23
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• 2009

The purpose of this study was to investigate the effects postural changes on respiratory muscles and acoustic parameters of the children with spastic cerebral palsy. Nine children with spastic cerebral palsy who required assistance when walking were selected. The ages of the children ranged from 6 to 9 years old. The phonation of the sustained vowel /a/ and the voice qualities of each child such as fundamental frequency($F_0$; Hz), pitch variation (Jitter; %), amplitude variation (Shimmer; %) and noise to harmonic ratio (NHR) were analyzed by Multi-Dimensional Voice Program (MDVP). The muscle activity of three major respiratory muscles: pectoralis major muscle, upper trapezius muscle and rectus abdorminalis muscle, were measured by examining the root mean square (RMS) of the surface EMG to investigate the impact of changes in the adjusted sitting posture of each subject. However, the RMS of pectoralis major muscle showed a significant differences (p<.05). Secondly, there were no significant differences in $F_0$, Jitter and Shimmer between pre and post posture change, but there was a significant difference in NHR (p<.05). The data were collected in each individual; once prior and once after the sitting posture change. The data were analyzed by Wilcoxon signed ranks-test using SPSS version 14.0 for Windows. The findings of this study were as follows; Firstly, the RMS of upper trapezius and rectus abdorminalis muscle were not significant different between pre and post sitting posture changes. From the result, it is concluded that changes in the adjusted sitting posture decreases the abnormal respiratory patterns in the children with spastic cerebral palsy which is characterized by the hyperactivity of the respiratory muscles in breathing. Also, there is increased on the voice qualities in children with spastic cerebral palsy.

• 대한후두음성언어의학회지
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• 제17권2호
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• pp.115-126
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• 2006

Background and Objectives : Training of breath support and laryngeal muscles control are important components in the development of the singing voice. The purpose of this study is to compare characteristics of respiratory and phonatory control on pitch, loudness, register change with untrained males and trained male singers. Materials and Methods : The 11 untrained males and 11 trained male singers participated. Closed Quotient(CQ), fundamental frequency (fo) and relative volume contribution of the rib cage (in percentage rib cage, % RC) and relative volume contribution of abdomen (in percentage abdomen, % AB) were measured during various pitch, loudness, register tasks using /a/ vowel phonation : Legato, staccato with C3-D3-E3-F3-G3 notes and crescendo and decrescendo with C3 note as well as modal register with C3 and falsetto register with C4 note using an integrated analysis system of Respiration, EGG and Voice. Results : (1) When pitch increased with legato task, loudness also increased in untrained male group but maintained in trained male singers. CQ was also increased both untrained and trained male singers but it was not significantly different ($p>.05$). The abdomen contribution to lung volume were significantly predominant both in inhalation and exhalation in trained males singers ($p<.05$). (2) When pitch increased with staccato task, CQ was not significantly different in untrained but significantly different in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$) (3) When loudness increased with crescendo, fo was significantly increased with increasing CQ in untrained males but fo was relatively consistent with increasing CQ in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). (4) Most male singers were able to change register from modal to falsetto register, but untrained males were not. Thus, CQ was significantly different between modal and falsetto register in trained male singers ($p<.05$). The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). Conclusion : Male singers were superior to untrained males in coordination of respiratory and phonatory control on pitch, loudness, register change. Implication are offered regarding how the results might be applied to the voice therapy as well as singing training.

• 대한후두음성언어의학회지
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• 제15권2호
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• pp.98-111
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• 2004

Background and Objectives : The purpose of this study is to analyze the difference of Fundamental Frequency(Hz), Closed Quotient(Qx ; %), Intensity(dB), Vocal tract length and width(cm), formant frequency(Hz), level of formant frequency(dB) depending on the larynx position. Materials and Methods : One professional male singer(career : 28 years) produced sustained vowel /a/,/e/,/i/,/o/,/u/ in two larynx position (higher, lower) with Dr. Speech and video fluoroscopy was used to quantify the vocal tract morphology. Results : In lower larynx position, CQ is increased 9.8% and Intensity is increased about 10% and level of Formant Frequency is increased. And also Vocal tract length is longer 2.4cm, Vocal tract width(Anterior width : 0.4cm, lateral width : 0.2cm) is wider than in higher larynx position. Conclusions : Singer's formant has a prominent spectrum envelope peak near 2400-2600Hz by clustering of F3, F4 and F5 near 3400Hz in lower larynx position.

• 한국지능시스템학회논문지
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• 제13권1호
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• pp.1-5
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• 2003

본 논문에서는 CCD 흑백 카메라를 이용하여 입력되는 인쇄체 한글 이미지의 문자를 인식하여 편집 가능한 텍스트 문서로 변환하는 시스템을 구현하였다 문자 인식에 있어서 잡음에 강한 경계선 기울기 방법을 이용함으로써 문자의 구조적 특성에 근거한 윤곽선 정보를 추출할 수 있었다. 이를 이용하여 각 문자 이미지의 수평 및 수직 모음을 인지하고 6가지 유형으로 분류한 후, 자소 단위로 분리하고 최대 길이 투영을 사용하여 모음을 인식하였다. 분리된 자음은 경계선이 변화되는 위상의 형태를 미리 저장된 표준 패턴과 비교하여 인식하였다. 인식된 문자는 KS 한글 완성형 코드로 문서 편집기에 출력되어 사용자에게 제공되는 시스템을 구현하였다.