• Proceedings of the KSPS conference
• /
• 2003.05a
• /
• pp.183-186
• /
• 2003

Speech recognition performance depends on various factors. One of the factors is the characteristic of a microphone which is used when speech data is collected. Thus, in the present experiment speech databases for tests are created through varying types of microphones. Then, acoustic models are built based on these databases, and each of the acoustic models is assessed by the data to determine recognition performance depending on various microphones.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.8
• /
• pp.24-30
• /
• 2001

This article is concerned with automatic segmentation for Korean speech signals. All kinds of transition cases of phonetic units are classified into 3 types and different strategies for each type are applied. The type 1 is the discrimination of silence, voiced-speech and unvoiced-speech. The histogram analysis of each indicators which consists of wavelet coefficients and SVF (Spectral Variation Function) in wavelet coefficients are used for type 1 segmentation. The type 2 is the discrimination of adjacent vowels. The vowel transition cases can be characterized by spectrogram. Given phonetic transcription and transition pattern spectrogram, the speech signal, having consecutive vowels, are automatically segmented by the template matching. The type 3 is the discrimination of vowel and voiced-consonants. The smoothed short-time RMS energy of Wavelet low pass component and SVF in cepstral coefficients are adopted for type 3 segmentation. The experiment is performed for 342 words utterance set. The speech data are gathered from 6 speakers. The result shows the validity of the method.

• The Journal of the Acoustical Society of Korea
• /
• v.13 no.6
• /
• pp.31-44
• /
• 1994

The paper introduces several studies of various aspects of Korean phonology and phonetics for speech recognition and synthesis. The phonological and phonetic studies presented in this paper are : i) For a study of segmental phonology, we made an annotated list of Korean allophones and their corresponding alphabetic symbols to type into computers. ii) For a study of segmental phonetics, we present some acoustic regulations in Korean consonants according to their phonological environment within a word. iii) For a study of prosodic phonology, we suggest the phonological functions of prosodic features and their acoustic cues. iv) For a study of prosodic phonetics, we present the characteristic patterns of accent and intonation in Korean. v) Finally, we suggest some ways of using this phonological and phonetic knowledge for possible improvement of speech recognition and synthesis.

• Proceedings of the KSPS conference
• /
• 2003.10a
• /
• pp.141-143
• /
• 2003

Speech recognition performance depends on various factors. One of the factors is the characteristic and established distance of a microphone which is used when speech data is collected. Thus, in the present experiment speech databases for tests are created through the type and established distance of a microphone. Then, acoustic models are built based on these databases, and each of the acoustic models is assessed by the data to determine recognition performance depending on various microphones and established microphone distances.

• MALSORI
• /
• no.52
• /
• pp.1-14
• /
• 2004

In this study, we investigated acoustic characteristics of imitated utterances by a professional voice imitator, focusing on prosodic properties such as vowel formants and f0 distribution. To see the patterns of a voice imitation by a professional voice imitator, we compared the imitator's voice data with target speakers' voice data. The professional imitator, Mr. Bae produced utterances imitating the former President Kim's, the comedian Choi's, and the singer Bae's voices. Auditorily, the imitator was judged to imitate all the target speakers' voices successfully. However, acoustic examination showed that the imitator was better at imitating the singer Bae's voice in that the imitator's and the singer Bae's voices are more alike with respect to vowel formants and f0 distribution. We infer this is because the imitator's normal voice is very similar to the singer Bae's voice. On the other hand, the imitator's voice data showed that the patterns of vowel formants and f0 distribution found in the imitator's imitation voices of the other two target speakers were different from those of target speakers' voices.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.5
• /
• pp.388-402
• /
• 2003

In this paper, we carried out the word, 4 continuous digits. continuous, and task-independent word recognition experiments to verify the effectiveness of the re-defined phoneme-likely units (PLUs) for the phonetic decision tree based HM-Net (Hidden Markov Network) context-dependent (CD) acoustic modeling in Korean appropriately. In case of the 48 PLUs, the phonemes /ㅂ/, /ㄷ/, /ㄱ/ are separated by initial sound, medial vowel, final consonant, and the consonants /ㄹ/, /ㅈ/, /ㅎ/ are also separated by initial sound, final consonant according to the position of syllable, word, and sentence, respectively. In this paper. therefore, we re-define the 39 PLUs by unifying the one phoneme in the separated initial sound, medial vowel, and final consonant of the 48 PLUs to construct the CD acoustic models effectively. Through the experimental results using the re-defined 39 PLUs, in word recognition experiments with the context-independent (CI) acoustic models, the 48 PLUs has an average of 7.06%, higher recognition accuracy than the 39 PLUs used. But in the speaker-independent word recognition experiments with the CD acoustic models, the 39 PLUs has an average of 0.61% better recognition accuracy than the 48 PLUs used. In the 4 continuous digits recognition experiments with the liaison phenomena. the 39 PLUs has also an average of 6.55% higher recognition accuracy. And then, in continuous speech recognition experiments, the 39 PLUs has an average of 15.08% better recognition accuracy than the 48 PLUs used too. Finally, though the 48, 39 PLUs have the lower recognition accuracy, the 39 PLUs has an average of 1.17% higher recognition characteristic than the 48 PLUs used in the task-independent word recognition experiments according to the unknown contextual factor. Through the above experiments, we verified the effectiveness of the re-defined 39 PLUs compared to the 48PLUs to construct the CD acoustic models in this paper.

• Proceedings of the KSPS conference
• /
• 2007.05a
• /
• pp.143-145
• /
• 2007

Muscle groups that are located in and around the vocal tract can produce audible changes in frequency and/or intensity of the voice. Vocal vibrato is a characteristic feature in the singing of performers trained in the western classical tradition and vibrato is generally considered to result from modulation in frequency amplitude and timbre. Vocal tremor is also characterized by periodic fluctuations in the voice frequency or intensity and vocal tremor is symptom of a neurological disease as Spasmodic dysphonia , Parkinson's disease. Vocal vibrato and Vocal tremor may have many of the same origins and mechanisms in the voice production systems. The purpose of this study is to find acostic character of Korean traditional song Pansori singer's vibrato and Spasmodic dysphonia patient's vocal tremor. twelve Pansori singers and seven Spasmodic dysponia patients participated to this study. Power spectrum and Real time Spectrogram are used to analyze the acoustic characteristics of Pansori singing and Spasmodic dysphonia patient's voice The results are as follows; First, vowel formant differences between Pansori singing and Spasmodic dysphonia patient's voice are higher F1, F3. Second, The vibrato rate show differences between Pansori singing and Spasmodic dysphonia patients;$4^{\sim}6/sec$ and $5{\sim}6/sec$ Vibrato rate of pitch is 5.7 Hz ${\sim}$ 42.4 Hz for Pansori singing , 3.8 Hz ${\sim}$ 27.9 Hz for Spasmodic dysphonia patients ;Vibrato rate of intensity range is 0.07 dB ${\sim}$ 8.26 dB for Pansori singing and 0.07 dB ${\sim}$ 4.81 dB for Spasmodic dysphonia patients

• The Journal of the Korea Contents Association
• /
• v.21 no.4
• /
• pp.658-667
• /
• 2021

Our study aimed to analyze and reinterpret, by an acoustic approach, the descriptions of the 18th century prosody and introduce the figurative pronunciation system, which is the International Phonetic Alphabet pioneer. Our methodology compares and analyzes grammars and documents on the transcription system and restructures the prosodic structure. It is certain that the 18th century grammarians widely accepted the prosody theories made by Arnauld & Lancelot of the seventeenth century. In particular, grammar scholars accepted the dichotomous classification of the accent structures as prosodic and oratorical accents. The prosodic accent has a relation to intonation, and the oratorical accent has as its key elements intonation and intensity. Regarding the temporal structure, the lengthening of the final syllable was observed systematically by grammarians of the 18th century. This time structure is similar to that of today. Therefore, we can conclude that the final elongation, an essential characteristic of the modern French accent, has already played an imbued role in 18th century prosody. Despite this, the 18th century grammarians did not assign it the status of accent, as it was a stereotype that matches accent with intonation.

• Phonetics and Speech Sciences
• /
• v.14 no.3
• /
• pp.87-101
• /
• 2022

In addition to administering a questionnaire (J-survey), which questions individuals on subjective vocal fatigue, voice samples were collected before and after speech-language pathology sessions from 50 female speech-language pathologists in their 20s and 30s in the Daejeon and Chungnam areas. We identified significant differences in Korean Vocal Fatigue Index scores between the fatigue and non-fatigue groups, with the most prominent differences in sections one and two. Regarding acoustic phonetic characteristics, both groups showed a pattern in which low-frequency band energy was relatively low, and high-frequency band energy was increased after the treatment sessions. This trend was well reflected in the low-to-high ratio of vowels, slope LTAS, energy in the third formant, and energy in the 4,000-8,000 Hz range. A difference between the groups was observed only in the vowel energy of the low-frequency band (0-4,000 Hz) before treatment, with the non-fatigue group having a higher value than the fatigue group. This characteristic could be interpreted as a result of voice abuse and higher muscle tonus caused by long-term voice work. The perturbation parameter and shimmer local was lowered in the non-fatigue group after treatment, and the noise-to-harmonics ratio (NHR) was lowered in both groups following treatment. The decrease in NHR and the fall of shimmer local could be attributed to vocal cord hypertension, but it could be concluded that the effective voice use of speech-language pathologists also contributed to this effect, especially in the non-fatigue group. In the case of the non-fatigue group, the rhamonics-to-noise ratio increased significantly after treatment, indicating that the harmonic structure was more stable after treatment.