• 음성과학
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• 제7권2호
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• pp.139-155
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• 2000

The aim of this research is to investigate acoustic characteristics of three different types of Korean Stops-plain, tensed, and aspirated-, and employ these as a base to determine which one(s) can be used as perceptual cues. In this paper, we have examined acoustic characteristics of Korean Stops, especially voice onset time(VOT), closure duration(CD), degree of pitch of following vowels and differences in the intensity of the Stops build-up after the onset of voicing. From the above characteristics, differences can be made between word-initial and word-medial positions. That is to say, in word-initial position, the three Korean Stops are distinguished by VOT and pitch, whereas in word-medial by CD, VOT and pitch. However, the acoustic characteristics do not have the same value as perceptual cues. In both word-initial, and medial positions, the immediately following vowels play the most important role in perceiving Korean Stops. And in case of word'-medial positions,. CD and VOT also play important perceptual roles. In order to have a more fine-grained distinction among Korean Stops, we think future research should be done to investigate which factor(s) of the following vowels is/are the most determinative perceptual cue(s). However, based on our investigation, we may conclude that it is highly plausible that pitch can be one of the most important perceptual cues when distinguishing the three Korean Stops.

• 말소리와 음성과학
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• 제7권1호
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• pp.57-65
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• 2015

This study aimed to identify the development pattern of final stop consonant perception using the gating task. Sixty-four subjects participated in the study: 16 children aged 4 years, 16 children aged 5 years, 17 children aged 6 years, and 15 adults. One-syllable words with consonant-vowel-consonant(CVC) structure, mokㄱ-motㄱ and papㄱ-patㄱ were used as stimuli in order to remove the redundancy of acoustic cues in stimulus words, 40ms-length (-40ms) and 60ms-length (-60ms) from the entire duration of the final consonant were deleted. Three conditions (the whole word segment, -40ms, -60ms) were used for this speech perception experiment. 48 tokens (4 stimuli ${\times}3$ conditions ${\times}4$ trials) in total were provided for participants. The results indicated that 5 and 6 year olds showed final consonant perception similar to adults in stimuli, papㄱ-patㄱ and only the 6-year-old children showed perception similar to adults in stimuli, 'mokㄱ-motㄱ. The results suggested that younger typically developing children require more acoustic information to accurately perceive final consonants than older children and adults. Final consonant perception ability may become adult-like around 6 years old. The study provides fundamental data on the development pattern of speech perception in normal developing children, which can be used to compare to those of children with communication disorders.

• 말소리와 음성과학
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• 제7권2호
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• pp.55-62
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• 2015

It is widely accepted that Parkinson's disease(PD) is the most common cause of hypokinetic dysarthria, and its characteristics of 'short rushes of speech' have become more evident along with the severity of motor disorders. Speech alternate motion rates (AMRs) are particularly useful for observing not only rate abnormalities but also deviant speech. However, relatively little is known about the characteristics of 'short rushes of speech' in terms of AMRs of PD except for the perceptual characteristics. The purpose of this study was to examine which acoustic features of 'short rushes of speech' in terms of AMRs are a robust indicator of Parkinsonian speech. Numbers of syllabic repetitions (/pə/, /tə/, /kə/) in AMR tasks were analyzed through acoustic methods observing a spectrogram of the Computerized Speech Lab in 9 patients with PD. Acoustically, we found three characteristics of 'short rushes of speech': 1) Vocalized consonants without closure duration(VC) 76.3%; 2) No consonant segmentation(NC) 18.6%; 3) No vowel formant frequency(NV) 5.1%. Based on these results, 'short rushes of speech' may affect the failure to reach and maintain the phonatory targets. In order to best achieve the therapeutic goals, and to make the treatment most efficacious, it is important to incorporate training methods which are based on both phonation and articulation.

• 한국음향학회지
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• 제32권2호
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• pp.167-173
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• 2013

본 논문은 이중모음을 분류하기 위한 음향음성학적 파라메터를 연구하였다. 음향음성학적 파라메터는 성도를 통해 음성이 발성될 때 나타나는 특징을 기반으로 하여 분산분석(ANOVA) 방법을 통해 선별한 모음의 길이, 에너지 궤적, 그리고 포먼트의 차이를 이용하였다. TIMIT 데이터 베이스를 사용하였을 때, 단모음과 이중모음만을 구분하는 실험에서는 17.8% 의 밸런스 에러율(BER)을 얻을 수 있었고, /aw/, /ay/, 그리고 /oy/를 단모음과 분류하는 실험에서는 각각 32.9%, 29.9%, 그리고 20.2%의 에러율을 얻을 수 있었다. 추가적으로 진행한 실험에서, 음향음성학적 파라메터와 음성인식에 널리 쓰이고 있는 MFCC를 함께 사용하였을 경우 역시 성능향상이 나타나는 것을 확인하였다.

• 음성과학
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• 제10권1호
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• pp.15-25
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• 2003

A laryngograph was developed to measure the open and closed movements of vocal folds in our laboratory. This study attempted to evaluate its performance by comparing its glottal data with that of the original laryngograph. Ten normal Korean adults Participated in the experiment. Each subject produced a sustained vowel /a/ for about five seconds. This study compared f0 values, contact quotients of the duration of closed vocal folds over one glottal pulse, and area quotients of the closed over open vocal folds derived from glottal waves using both the original and new laryngographs. Results showed that the mean and standard deviation of the two laryngographs were almost comparable with a correlation coefficient 0.662 but minor systematic shift below those of the original laryngograph was observed. The absolute mean difference converged into 1 Hz, which indicates a possibility of adopting some threshold of rejecting inappropriate pitch values beyond a threshold value. The contact quotient of the normal subjects came out slightly over the 50% in a citation speech. Finally, the area quotient converged into 1. We will pursue further studies on the abnormal patients in the future.

• 대한후두음성언어의학회지
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• 제33권2호
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• pp.64-76
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• 2022

Praat is a useful analysis tool for linguists, engineers, doctors, speech-language pathologits, music majors, and natural scientists. Basic parameters including duration, pitch, energy and perturbation parameters such as jitter and shimmer can be easily measured and manipulated in the sound editor. When a more in-depth analysis is needed, it is recommended to understand the advanced menus of the object window and learn how to use them. Among the object window menus, vowel formant analysis, spectrum analysis, and cepstrum analysis can be cited as useful ones in the clinical field. The spectrum object can be usefully used for voice quality measurement and diagnosis of patients with voice disorders by showing the energy distribution according to frequency axis (domain). A cepstrum object is useful for speech analysis when periodicity of the sound object is not measurable. The low to high ratio obtained from the spectral object and the CPPs measured from the cepstrum object have attracted many researchers, and it has been proven that the CPPs measured in Praat are relatively excellent.

• 말소리와 음성과학
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• 제15권3호
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• pp.1-7
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• 2023

This study investigates how the phonological and phonetic information of vowels influences prosodic prominence among linguistically untrained listeners using public speech in American English. We first examined the speech material's phonetic realization of vowels (i.e., maximum F0, F0 range, phone rate [as a measure of duration considering the speech rate of the utterance], and mean intensity). Results showed that the high vowels /i/ and /u/ likely had the highest max F0, while the low vowels /æ/ and /ɑ/ tended to have the highest mean intensity. Both high and low vowels had similarly high phone rates. Next, we examined the effects of the vowels' phonological and phonetic information on listeners' perceptions of prosodic prominence. The results showed that vowels significantly affected the likelihood of perceived prominence independent of acoustic cues. The high and low vowels affected probability of perceived prominence less than the mid vowels /ɛ/ and /ʌ/, although the former two were more likely to be phonetically enhanced in the speech than the latter. Overall, these results suggest that perceptions of prosodic prominence in English are not directly influenced by signal-driven factors (i.e., vowels' acoustic information) but are mediated by expectation-driven factors (e.g., vowels' phonological information).

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권1호
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• pp.48-58
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• 2001

After performing mandibular setback surgery, we found some changes in patterns and organs of speech. This investigation was undertaken to investigate the aspect and degree of speech patterns according to the amount of surgical setback in mandibular prognathic patients. Thirteen patients with skeletal Class III malocclusion were studied preoperative and postoperative over 6 months. They had undergone the mandible setback operation via bilateral sagittal split ramus osteotomy(BSSRO). We split the patients into two groups. Group 1 included patients whose degree of mandibular setback was 6mm or less, and Group 2 above 6mm. Control group was two adults wish normal speech patterns. A phonetician performed narrow phonetic transcriptions of tape-recorded words and sentences produced by each of the patients and the acoustic characteristics of the plosives, fricatives, and flaps were analyzed with a phonetic computer program (Computerized Speech Lab(CSL) Model 4300B(USA)). The results are as follows: 1. Generally, Patients showed longer closure duration of plosives, shorter VOT(voice onset time) and higher ratio of closure duration against VOT. 2. Patients showed more frequent diffuse distribution than the control group in frication noise energy of fricatives. 3. In fricatives, frequency of compact from were higher in group 1 than in group 2. 4. Generally, a short duration of closure for /ㄹ/ was not realized in the patient's flaps. Instead, it was realized as fricatives, sonorant with a vowel-like formant structure, or trill type consonant. 5. Abnormality of the patient's articulation was reduced, but adaptation of their articulation after surgery was not perfect and the degree of adaptation was different according to the degree of surgical setback.

• 한국음향학회지
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• 제25권2호
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• pp.88-95
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• 2006

본 논문에서는 대화체 음성에 대한 음성 인식의 성능을 향상시키기 위한 방법으로, 고속 발화음에 대해 강인한 음성 인식 방법을 제안하고 성능을 평가하였다. 제안된 기법은 입력된 음성의 속도를 정량화하여 나타내기 위한 부가적인 음성 인식 과정이 필요치 않으며, 특정 대역내의 에너지 분포를 이용하여 모음 구간을 판정하고, 단위 시간당 모음의 개수를 구하여 음성의 속도를 측정하였다. 빠른 발성음에 대한 음성 인식의 성능을 향상시키기 위해, 기존의 방법은 표준 음소 길이와 측정된 음소 길이간의 비율을 이용하여 특징 벡터를 시간축으로 확장하였다. 제안된 방법에서는 발성 속도에 따라 음성을 분류하고, 분류된 음성에 대해 서로 다른 시간축 확장 비율을 정하도록 하였다. 여기서 분류에 필요한 문턱치들과 시간축 확장 비율들은 최대 우도 방법을 이용하여 구하였다. 10자리 이동 전화 번호에 대한 음성 인식의 실험 결과, 제안된 기법에 의해 전체적으로 $17.8\%$ 오류율이 감소되는 것을 확인할 수 있었다.

• Clinical and Experimental Pediatrics
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• 제50권9호
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• pp.896-900
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• 2007

목 적 : 정량적인 분석으로 양성 로란딕 간질환자의 간질파 발생위치에 따른 음성 언어적 특성을 알아보고자 하였다. 방 법 : 항경련제를 사용한 적이 없고, 임상 증상과 검사 소견으로 양성 로란딕 간질 증후군에 합당한 초진 환자 23명을 대상으로 음성 언어 분석을 하였다. 음성언어평가는 Computerized Speech Lab을 사용하여 분석하였다. 결 과 : 간질파 위치가 좌뇌인 환자군에서 치환에 의한 조음 오류가 빈번하게 관찰되었다. 환자군의 VOT는 정상아동($46.7{\pm}10.2ms$)과 비교해 훨씬 길게 나타났으며 특히 간질파 발생위치가 좌뇌인 환자군에서($74.3{\pm}36.6ms$) 더욱 길게 나타났다. 억양형태를 비교분석한 결과, 간질파 발생위치가 우뇌인 환자군에서 간질파 발생위치가 좌뇌인 환자군 보다 억양변화가 적어 운율 변동 폭이 낮은 것으로 평가되었다. 숫자세기의 자발화 길이측정에서 간질파 발생위치가 좌뇌인 환자군이 간질파 발생위치가 우뇌인 환자군 보다 길게 측정되었다. 결 론 : 양성 경과를 보이는 양성 로란딕 간질 환자에서도 조음오류 및 유창성 등 음성 언어적 문제점을 정량적으로 확인하였다. 따라서 양성 로란딕 간질환자의 진단과 치료 과정 중 언어음성학적인 평가를 포함시킬 것을 추천하고자 한다.