• Speech Sciences
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• v.11 no.2
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• pp.105-117
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• 2004

Recently, many scholars have emphasized the importance of English listening ability for smoother communication. Most audio materials, however, were recorded in a quiet sound-proof booth. Therefore, students who have spent so much time listening to the ideal audio materials are expected to have difficulty communicating with native speakers in the real life. In this study, we examined how well thirty three Korean university students and five native speakers will repeat the recorded English sentences under noise and speed conditions. The subjects' production was scored by listening to each recorded sentence and counting the number of words correctly produced and determined the percent ratios of correctly produced words to the total words in each sentence. Results showed that the student group correctly repeated around 65% of all the words in each sentence while the native speakers demonstrated almost perfect match. It seemed that the students had difficulty perceiving and repeating function words in various conditions. Also, high-proficiency student group outperformed the low-proficiency student group particularly in their repetition of function words. In addition, the student subjects' accuracy of repetition remarkably dropped when the normal sentences were both sped up and mixed with noise. Finally, it was observed that the Korean students' percent correct ratio fell down as the stimulus sentence became longer.

• Speech Sciences
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• v.9 no.1
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• pp.17-26
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• 2002

Voice onset time (VOT) is defined as the time interval from the oral release of a stop consonant to the onset of glottal pulsing in the following vowel. VOT is a temporal characteristic of stop consonants that reflects the complex timing of glottal articulation relative to supraglottal articulation. There have been many reports on efforts to clarify the acoustical and physiological properties that differentiate the three types of Korean stops, including acoustic, fiberscopic, aerodynamic and electromyographic studies. In the acoustic and fiberscopic studies for stop consonants, the voice onset time and glottal width during the production of stops has been known as the longest and largest in the heavily aspirated type followed by the slightly aspirated type and unaspirated types. The thyroarytenoid and posterior cricoarytenoid muscles were physiologically inter-correlated for differentiating these types of stops. However, a review of the English literature shows that the fine movement of the mucosal edges of the vocal folds during the production of stops has not been well documented. In recent. years, a new method for high-speed recording of laryngeal dynamics by use of a digital recording system allows us to observe with fine time resolution. The movements of the vocal fold edges were documented during the period of stop production using a fiberscopic system of high speed digital images. By observing the glottal width and the visual vibratory movements of the vocal folds before voice onset, the heavily aspirated stop was characterized as being more prominent and dynamic than the slightly aspirated and unaspirated stops.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.35-43
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• 2000

This paper was studied on developmental direction of telecommunications for disabilities welfare. Method of this study is delphi method. Persons with disabilities is classed as motor disability, visual handicap, hearing impairment, and language and speech disorders. Persons with motor disability is needs as follow, speed recognition technology, video recognition technology, breath capacity recognition technology. Persons with visual handicap is needs as follow, display recognition technology, speed recognition technology, text recognition technology, intelligence conversion handling technology, video recognition - speed synthetic technology. Persons with hearing impairment and language - speech disorders is needs as follow, speed signal handling technology, speed recognition technology, intelligence conversion handling technology, video recognition technology, speed synthetic technology the results of this study is as follow: first, disabilities telecommunications organization must be constructed. Second, persons with disabilities in need of universal service. Third, Persons with disabilities in need of information education, Fourth, studying for telecommunications in need of support. Fifth, small telecommunications company in need of support. Sixth, software industry in need of new development. Seventh, Persons with disabilities in need of standard guideline for telecommunications.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.93-99
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• 2017

A hybrid approach using Long Short Term Memory (LSTM) Recurrent Neural Network (RNN) has showed great improvement in speech recognition accuracy. For training acoustic model based on hybrid approach, it requires forced alignment of HMM state sequence from Gaussian Mixture Model (GMM)-Hidden Markov Model (HMM). However, high computation time for training GMM-HMM is required. This paper proposes an end-to-end approach for LSTM RNN-based Korean speech recognition to improve learning speed. A Connectionist Temporal Classification (CTC) algorithm is proposed to implement this approach. The proposed method showed almost equal performance in recognition rate, while the learning speed is 1.27 times faster.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1744-1749
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• 2013

Acoustic feedback is perceived as whistling or howling, which is a major complaint of hearing-aids users. Acoustic feedback cancellation is important in hearing-aids because acoustic feedback degrades performance of the hearing aid device by reducing maximum insertion gain. Adaptive systems for estimate acoustic feedback path and feedback suppression algorithms have been proposed in order to solve this problem. A typical feedback cancellation algorithm is LMS(least mean squares) because of its computational efficiency. However it has problem of convergence performance in high correlated input signal. In this paper, we propose a new variable step-size normalized LMS(least mean squares) algorithm using VAD(voice activity detection) to overcome the limitation of the LMS algorithm. The VAD algorithm is GSAP(global speech absence probability) and the feedback cancellation algorithm is normalized LMS. The proposed algorithm applies different step-size between voice and non-voice using VAD, for high stability, fast convergence speed and low misalignment when correlated inputs, such as speech. The result of simulation with white noise mixed speech signal, the proposed algorithm shows high performance then traditional algorithm in terms of stability, convergence speed and misalignment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1276-1283
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• 2016

The scale of financial damages on voice fishing has not been decreased despite of national and social efforts to reduce the amounts of voice fishing damage. One of these reasons is a sophisticated and vernacular speech style that makes it difficult to recognize the offenders. Furthermore, nowadays, young men have intensively been deceived by not only sophisticated and vernacular speech style which is used the employer of real public offices but also obtained personal information. As a result, this lead directly to the financial damages of younger people who has a stronger judgement than older. For this, we investigated the comparison and analysis between the criminals of voice fishing and the same generation younger people for identifying voice features. The experiment was carried out based on the pitch, bandwidth of pitch, energy, speech speed and voice color for searching the difference of voice characteristics between the criminals of voice fishing and the same generation younger people since 2011. The experimental result shows that there is a significant difference in energy and speech speed between the criminals of voice fishing and the same generation younger people.

• Therapeutic Science for Rehabilitation
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• v.9 no.1
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• pp.79-90
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• 2020

Objective : The purpose of this study was to investigate the age, motor function, and characteristics of feeding and articulation in children with spastic cerebral palsy. Methods : This study included 34 boys and 27 girls who lived in Seoul, Gyeonggi, Daegu, Daejeon, or Busan, and were diagnosed with cerebral palsy by rehabilitation doctors. A total of 61 children with cerebral palsy were identified as dependent variables for verbal intelligibility, diadochokinesis speed and intelligibility. Multiple regression analysis was performed. Results : Verbal intelligibility among the articulating abilities of children with spastic cerebral palsy was significantly associated with the non-speech mechanisms of cup drinking, and spoon feeding. Diadochokinesis speed was significantly associated with the speech mechanism of porridge feeding, the non-speech mechanism of cup drinking, and motor function. Diadochokinesis intelligibility also showed significant results with regards to the speech mechanism of porridge feeding and the non-speech mechanism of cup drinking. Conclusion : It is useful to evaluate and treat eating function by considering speech and non-speech mechanisms and motor function, according to eating function, among the variables related to articulation ability in children with spastic cerebral palsy. In addition, it would be very useful to study the improvement of articulation abilities after developing and applying a feeding program for children with cerebral palsy.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.173-184
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• 2010

The purpose of this study is to investigate the speech rate characteristics (whole speech rate, articulation speech rate, and articulation percentage) and the pause characteristics (pause duration, pause frequency, and pause percentage) of Korean-speaking patients with idiopathic Parkinson's disease (referred to as IPD hereafter). The study aims first to examine the differences between the patient group with IPD and the other group without IPD concerning those measurements, and secondly to investigate the relevant measurements of the two groups following the sentence length changes. There were two groups of subjects in this study. The first group consisted of 7 subjects between the ages of 50 and 60 who were diagnosed as IPD with mild severity, and the second group consisted of 13 subjects without IPD who matched the age and gender of those in the first group. Those two groups were asked to read 8 different sentences in length at habitual speed. Speech rate and pause characteristics of the two groups were measured and compared each other. The followings results were observed. First, in a study of speech rate characteristics, the whole speech rate and the articulation speech rate of the patient group scored within the normal range, which is same as the group without IPD. On the other hand, with regard to the pause characteristics, differences between two groups were shown; the patient group had shorter pause duration, lower pause frequency, lower pause percentage, and higher articulation percentage. Secondly, in a study of relevant measurements following the sentence length, both groups showed a tendency for whole speech rate and articulation rate to increase as the length of the sentence increased, but the result of pause characteristics showed a difference between two groups. While the group without IPD showed a longer pause duration, higher pause frequency, and higher pause percentage as the length of sentences increases, no differences were shown among the patient group concerning the length of sentences. This study suggests a result that the patients with IPD of mild severity retained a normal speech rate and examined pause characteristics of the patient group which showed a different result from the group without IPD in terms of quality. Future studies on the speech rate and pause characteristics of Korean-speaking patients with IPD in various severities.

• MALSORI
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• no.43
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• pp.57-72
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• 2002

The technology of speech recognition has a wide field of application. The range of such technology is spreading into mobile computing having the large amount of movement for communication equipments at the present time. Particularly, recognition in internet environment is rapidly moving into mobile environment. Because of these environments, users want the faster speed of data transmission and the lighter portable equipment for data access. That is PDA(Personal Digital Assistant). Therefore, we designed a triphone-based text independent vocabulary recognizer for the implementation of speech control in this paper. The text independent vocabulary recognizer is based on the state .joint algorithm with decision trees

• Proceedings of the KSPS conference
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• 1997.07a
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• pp.81-91
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• 1997

This paper deals with the problems of English listening comprehension: the rate of understanding difference in positions and sentence structures, parts of speech easily missed to understand, English sounds only in English(not in Korean), confusion of sounds, unaccented prefixes and suffixes, polysemy, homonym, juncture, understanding as one word by two different words, and sound blending in a normal speed of connected speech. Bearing those in mind I taught Suwon University freshmen video English with the mixed idea of Peterson's bottom-up and top-down methods putting in a meaningful context with thought group rather than word to word understanding. As a consequence, their errors come: prepositions, conjunctions, unstressed prefixes and suffixes, -ing from the present progressives and so forth. Assignments to have students transcribe the TV commercials and the names of reporters or Korean related news from English broadcastings are of use and help.