• 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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• 제9권1호
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• pp.137-148
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• 2002

This study investigates phonation modes of vowels following the affricate consonants in Korean and English- -tense affricate /c'/, lenis affricate /c/, and aspirated affricate /$c^{h}$/ for Korean; voiced affricate /$\check{J}$/ and aspirated affricate /c/ for English. The investigation makes significant use of the H1*-H2* measure (a normalized amplitude difference between the first and second harmonics) to provide acoustic correlates of the phonation types. The major findings for English are that the H1*-H2* measure at the vowel onset was significantly larger in post-aspirated position than in post-voiced position. The Korean data showed the H1*-H2* measure at the vowel onset to be significantly higher in the post-aspirated class than in the post-tense class. On the other hand, the Fo values for the post-lenis vowels were significantly lower than those of the other two classes during the first half of the vowel. Based on the phonetic results, this study argues for the need to incorporate the [stiff vocal folds] and [slack vocal folds] features into the phonological treatments of Korean affricates, while maintaining the two features [constricted glottis] and [spread glottis].

• 한국임상수의학회지
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• 제28권1호
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• pp.94-100
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• 2011

This study was performed to describe the radiographic and ultrasonographic features of retained surgical gauze known as gossypiboma in 9 dogs. Female dogs (n = 8) were at higher risk and seven out of the eight cases had a history of ovariohysterectomy. Seven dogs were symptomatic and the most common clinical signs were vomiting, anorexia, and inertia. A palpable abdominal mass was detected in six dogs. Radiographic signs included a localized abdominal mass with soft tissue density (n = 7) or a mass containing speckled gas (n = 1). Ultrasonography showed a hypoechoic mass with a hyperechoic center (n = 4), or a homogeneous hypoechoic mass (n = 3). The remaining dogs (n = 2) showed an intestinal wall surrounding a hyperechoic center. Regardless of the characteristics of a mass, an acoustic shadowing was accompanied from the center of a mass in all dogs. Ultrasonography also revealed complications such as adhesion between a mass and adjacent organs, and peritonitis and intestinal obstruction around a mass. The gossypiboma can be considered when a hypoechoic mass accompanying a hyperechoic center with acoustic shadowing is observed on ultrasound examination.

• 음성과학
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• 제6권
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• pp.197-217
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• 1999

In a noisy class, the acoustic-phonetic features of the teacher and the perceptual features of learners are changed comparison with a quiet environment. Acoustical analyses were carried out on a set of French monosyllables consisting of 17 consonants and three vowel /a, e, i/, produced by 1 male speaker talking in quiet and in 50, 60 and 70 dB SPL of masking noise on headphone. The results of the acoustic analyses showed consistent differences in energy and formant center frequency amplitude of consonants and vowels, $F_1$ frequency of vowel and duration of voiceless stops suggesting the increase of vocal effort. The perceptual experiments in which 18 undergraduate female students learning French served as the subjects, were conducted in quiet and in 50, 60 dB of masking noise. The identification scores on consonants were higher in Lombard speech than in normal speech, suggesting that the speaker's vocal effort is useful to overcome the masking effect of noise. And, with increased noise level, the perceptual response to the French consonants given had a tendency to be complex and the subjective reaction score on the noise using the vocabulary representative of 'unpleasant' sensation to be higher. And, in the point of view on the L2(second language) acquisition, the influence of L1 (first language) on L2 examined in the perceptual result supports the interference theory.

• 말소리와 음성과학
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• 제15권2호
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• pp.53-59
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• 2023

Detection of children with autism spectrum disorder (ASD) based on speech has relied on predefined feature sets due to their ease of use and the capabilities of speech analysis. However, clinical impressions may not be adequately captured due to the broad range and the large number of features included. This paper demonstrates that the knowledge-driven speech features (KDSFs) specifically tailored to the speech traits of ASD are more effective and efficient for detecting speech of ASD children from that of children with typical development (TD) than a predefined feature set, extended Geneva Minimalistic Acoustic Standard Parameter Set (eGeMAPS). The KDSFs encompass various speech characteristics related to frequency, voice quality, speech rate, and spectral features, that have been identified as corresponding to certain of their distinctive attributes of them. The speech dataset used for the experiments consists of 63 ASD children and 9 TD children. To alleviate the imbalance in the number of training utterances, a data augmentation technique was applied to TD children's utterances. The support vector machine (SVM) classifier trained with the KDSFs achieved an accuracy of 91.25%, surpassing the 88.08% obtained using the predefined set. This result underscores the importance of incorporating domain knowledge in the development of speech technologies for individuals with disorders.

• 전기전자학회논문지
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• 제13권2호
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• pp.132-139
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• 2009

본 논문에서는 핸즈프리 통신에서의 반향제거를 위한 음성 특징 기반의 동시통화 검출 기법을 제안한다. 동시통화 검출은 반향제거를 위한 적응 필터의 적응을 제어하는 역할을 하기 때문에 매우 중요한 분야이다. 이전까지의 연구에서는 동시통화 검출을 음성의 특징에 대한 고려 없이 단순히 신호처리 영역에서만 이루어졌다. 하지만 제안한 기법에서는 음성인식으로 사용되는 음성 특징을 핸즈프리 통신상에서의 근단 화자와 원단화자 사이의 차별성을 가지는 특징으로 사용하였다. 제안한 방식이 시간 축에서의 파형만을 이용하여 판단하는 동시통화검출기보다 우수한 성능을 나타내는 것을 실험을 통하여 입증하였다.

• 한국컴퓨터정보학회논문지
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• 제19권4호
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• pp.55-62
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• 2014

본 논문에서는 유도 전동기 결함 중 가장 많은 비중을 차지하는 베어링의 복합 결함을 검출하기 위해 음향 방출 신호와 이를 영상화하여 질감 분석을 이용한 결함 검출 방법을 제안한다. 영상화된 결함 신호가 갖는 엔트로피, 픽셀의 동질성 및 에너지 특징을 분석하고, 그레이-레벨 동시발생 행렬을 통해 영상의 에너지, 동질성 및 다양성의 세 가지 질감 특징을 추출한다. 추출된 세 가지 질감 특징을 퍼지-ARTMAP(Fuzzy-ARTMAP)의 입력으로 사용하여 베어링의 외륜-내륜, 내륜-롤러 및 외륜-롤러에 대한 복합 결함을 분류한다. 총 10회에 걸쳐 제안한 방법의 분류 성능을 평가한 결과, 100%의 분류 정확성을 보였다.

• 한국음향학회지
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• 제19권1호
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• pp.4-10
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• 2000

본 논문은 자동 음소 분할기의 음소 경계 오류를 보상하기 위한 후처리(Postprocessing)에 관한 연구이다. 자동 분절 경계의 오류 범위를 줄일 수 있는 후처리기를 제안하고, 자동 분절 결과를 직접 합성 단위로 사용할 수 있는 대량의 합성용 운율데이터 베이스 구축에 유용함을 기술한다. 제안된 후처리기는 수작업으로 보정된 데이터의 특징벡터를 다층 신경회로망(MLP: Multi-layer perceptron)을 통해 학습을 한 후, 자동 분절 결과와 MLP 기반 후처리를 이용하여 새로운 음소 경계를 추출한다. 우선, 특징벡터 set은 음성학적 지식이 최대한 반영되도록 선정되었다. 그리고, 경계를 추출하기 위해서 비선형 패턴분리에 탁월한 성능을 보이는 MLP를 이용한다. MLP는 매우 다양하게 나타나는 음소 경계간 음성학적 특징을 단시간 내에 적용할 수 있기 때문이다. 마지막으로, 음운환경별로 특징 벡터가 적용되는 제안된 후처리 알고리즘을 이용하여 자동 분절의 경계 오류에 대한 보상이 이루어진다. 문장 단위로 발화된 합성용 데이터베이스에서 후처리기로 보정된 분절 결과는 음성 언어 번역 시스템의 분할율보다 약 19.9%의 향상된 성능을 보였으며, 절대오류 (｜Hand label position-Auto label position｜)는 약 28.6% 감소되었다.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2006년도 춘계 학술대회 발표논문집
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• pp.77-81
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• 2006

This paper presents a technique of imposing the prosodic features of a native speaker's utterance onto the same sentence uttered by a non-native speaker. Three acoustic aspects of the prosodic features were considered: the fundamental frequency (F0) contour, segmental durations, and the intensity contour. The fundamental frequency contour and the segmental durations of the native speaker's utterance were imposed on the non-native speaker's utterance by using the PSOLA (pitch-synchronous overlap and add) algorithm [1] implemented in Praat[2]. The intensity contour transfer was also done in Praat. The technique of transferring one or more of these prosodic features was elaborated and its implications in the area of language education were discussed.

• 말소리와 음성과학
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• 제8권3호
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• pp.39-49
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• 2016

The present study examined the change of aerodynamic features after laryngomicrosurgery in patients with vocal polyps. Aerodynamic evaluation was performed in thirty-nine patients (15 males and 24 females) one week before surgery and four weeks after surgery. Evaluation protocols of vital capacity, maximum sustained phonation(MXPH), and voicing efficiency(VOFT) were used to collect 29 phonatory aerodynamic measures, requiring voice with a comfortable pitch and loudness. Statistically significant changes were found for phonation time and airflow values in the MXPH protocol, while changes were also found for airflow values, subglottal pressure values and acoustic resistance values in the VOFT protocol. Although phonation time was increased in both male and female patients, gender-dependent changes were found in airflow measurements. Men's phonation time increased with no difference in airflow rate, but women's phonation time increased with decreased airflow rate and lower subglottal pressure. The changes of aerodynamic features may be affected by women's self-perceived change for vocal attitude, which was reducing sense of vocal effort after surgery.