• Speech Sciences
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• v.10 no.2
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• pp.57-64
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• 2003

The cepstrum coefficients are the most popular feature for speech recognition or speaker recognition. The cepstrum coefficients are also used for speech synthesis and speech coding but has major drawback of long processing time. In this paper, we proposed a new method that can reduce the processing time of FFT cepstrum analysis. We use the normal ordered inputs for FFT function and the bit-reversed inputs for IFFT function. Therefore we can omit the bit-reversing process and reduce the processing time of FFT ceptrum analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5495-5501
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• 2014

Individuals with a left frontal brain injury show significant impairments in their speech ability. The aims of the present study were (1) to assess and compare the ability of speech acts comprehension and executive function between individuals with a left frontal brain injury and normal individuals, and (2) to investigate the correlation of speech act comprehension ability factors. The study's subjects were 18 individuals with a left frontal brain injury and 18 normal control adults of the same age, gender, and educational age. The following results were obtained. First, the group of individuals with a left frontal brain injury had lower speech act comprehension, executive function than the normal control group. Second, the speech act comprehension ability of the individuals with a left frontal brain injury showed a high correlation with the executive function.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.406-413
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• 2019

This paper proposes a speech enhancement method through the process of combining the gain function with spectrum subtraction method in the two microphone array with close spacing. A speech enhancement method that uses a gain function estimated by the SNR (Signal-to Noise Ratio) based on the multi frequency band coherence function causes the performance degradation in high correlation between input noises of two channels. A new speech enhancement method is proposed where the weighted gain function is used by combining the gain function from the spectral subtraction. The performance evaluation of the proposed method was shown by comparison with PESQ (Perceptual Evaluation of Speech Quality) value which is an objective quality evaluation test provided by the ITU-T (International Telecommunications Union Telecommunication). In the PESQ tests, the maximum 0.217 of PESQ value is improved in the various background noise environments.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.30 no.2
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• pp.87-94
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• 2019

The purpose of this study was to investigate the speech characteristics and speech therapy of Parkinson disease (PD). This study selected 28 papers published in Korea from 1998 to 2018 after searching the terms 'Parkinson voice' and 'Parkinson speech therapy.' Literature review had been conducted in the two aspects of speech characteristics and speech therapy. The speech characteristics were divided into respiration, phonation, articulation, prosody, vowel production, and voice questionnaire. Speech therapy was divided into Lee Sliverman voice treatment (LSVT) and other voice therapy. PD patients did not differ in respiration function compared to normal elderly people, but their speech and articulation function were poorer. There was also a difference in the speech rate, frequency of pause, and accuracy of vowel production compared with normal elderly people. PD had a lower VHI score and their voice related quality of life was a little poorer. The LSVT was typically used in speech therapy for PD. The methods of speech therapy for PD have been shown to improve respiration and phonation. It is necessary to establish voice norms in PD patients and develop effective speech therapy in the following study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.150-155
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• 2006

Speech intelligibility is investigated on a conference room-window glass coupled system. Using MLS(Maximum Length Sequency) signal as a sound source, acceleration and velocity responses of the window glass are measured by accelerometer and laser doppler vibrometer. MTF(Modulation Transfer Function) is used to identify the speech transmission characteristics of the room and window system. STI(Speech Transmission Index) is calculated by using MTF and speech intelligibility of the room and the window glass is estimated. Speech intelligibilities by the acceleration signal and the velocity signal are compared and the possibility of the wiretapping is investigated. Finally, intelligibility of the conversation sound is examined by the subjective test.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.363-369
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• 2007

The purpose of the study is to obtain acoustical information to prevent eavesdropping of the glass window. Speech intelligibility was investigated on the vibration sound detected from the glass window of a conference room. Objective test using speech transmission index(STI) was performed to estimate quantitatively the speech intelligibility. STI was determined based on tile modulation transfer function(MTF) of the room-glass window system. Using Maximum Length Sequency(MLS) signal as a sound source, impulse responses of the glass window and MTF were determined by signals from accelerometers and laser doppler vibrometer. Finally, speech intelligibility of the interior sound and window vibration were compared under different sound pressure levels and amplifier gains to confirm the effect of measurement condition on the speech intelligibility.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.888-894
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• 2007

The speech sound is detected by the vibration measurement of the window glass. In this study, we investigate the effect of the disturbing waves by background noise and window shaker excitation on the speech intelligibility of the detected sound. Based upon Modulation Transfer Function(MTF), speech intelligibility of the sound is objectively estimated by Speech Transmission Index(STI) As the level of the disturbing wave varies, variation of the speech intelligibility is examined. Experimental result reveals how STI is influenced by the level and frequency characteristics of the disturbing wave. By using a customized window shaker for disturbing sound, we evaluate the efficiency and the frequency characteristics of the anti-eavesdropping system. The purpose of the study is to provide useful information to prevent the eavesdropping through the window glass.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.4
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• pp.197-202
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• 2013

Large gains in speech intelligibility can be obtained using the SNR-based binary mask approach. This approach retains the time-frequency (T-F) units of the mixture signal, where the target signal is stronger than the interference noise (masker) (e.g., SNR > 0 dB), and removes the T-F units, where the interfering noise is dominant. This paper introduces two alternative binary masks based on the distortion constraints to improve the speech intelligibility. The distortion constraints are induced by a gain function for estimating the short-time spectral amplitude. One binary mask is designed to retain the speech underestimated (T-F) units while removing the speech overestimated (T-F)units. The other binary mask is designed to retain the noise overestimated (T-F) units while removing noise underestimated (T-F) units. Listening tests with oracle binary masks were conducted to assess the potential of the two binary masks in improving the intelligibility. The results suggested that the two binary masks based on distortion constraints can provide large gains in intelligibility when applied to noise-corrupted speech.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.994-1003
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• 1994

In this paper, a scheme of noise cancellation using spectral subreaction method with single input in an autombile noise environment is proposed. In order to remove the changing automonile noise components form the noisy speech signal, the noise of various states is analyzed and its characteristics are presented. For the decision of speech/nonspeech and the estimation of noise spectrum, a classification function is proposed on the basis of noise analysis. This function presents the precise decision of speech/nonspeech and the optimal estimation of noise spectrum with less computation. As the result of the estimation of noise spectrum by the proposed classification function, the clean speech signal is extracted from the noisy speech signal with high signal-to-ratio.

• Phonetics and Speech Sciences
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• v.9 no.2
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• pp.125-135
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• 2017

The current study examines PCC (percentage of correct consonant), speech intelligibility, and oral motor function between the group of typically developing children and the group of children with Down's syndrome. To 15 children with Down's syndrome (mean CA: 9;7) and 15 typically developing children on receptive language age, the following tests were administered: K-WPPSI (2001), Picture Vocabulary Test (Kim et al., 1995), Oral and Speech Motor Control Protocol for total oral functional score (Robbins et al., 1987), DDK and Assessment of Phonology and Articulation for Children (APAC, Kim et al., 2007) for PCC and speech intelligibility. Pearson correlation coefficients were computed for the total oral functional score, PCC and DDK of each group. The statistical analysis showed that there is no significant difference in total functional score and DDK when IQ was controlled. There was a significant correlation between total oral functional score and PCC in the Down's syndrome group and a significant correlation between total oral functional score and intelligibility in the Down's syndrome group whether IQ was controlled or not. The findings suggest that both cognitive ability and overall oral motor function need to be considered for the intervention to enhance PCC or speech intelligibility of children with Down's syndrome.