• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.349-350
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• 2006

This paper presents very low bit rate speech coder, ZFE-CELP(ZINC Function Excitation-Code Excited Linear Prediction). The ZFE-CELP speech codec is based on a ZINC function and CELP modeling of the excitation signal respectively according to the frame characteristic such as a voiced speech and an unvoiced speech. And this paper suggest strategies to improve the speech quality of the very low bit rate speech coder.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
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• pp.149-151
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• 2007

This study was designed to investigate fast ab/adduction rate of articulation valves in normal adults. The measurement of fast ab/aduction rate has traditionally been used for assessment, diagnosis and therapy in patients who suffered from dysarthria, functional articulation disorders or apraxia of speech. Fast ab/adduction rate shows the documented structural and physiological changes in the central nervous system and the peripheral components of oral and speech production mechanism. Fast ab/adduction rates were obtained from 20 normal subjects by producing the repetition of vocal function (/ihi/), tongue function (/t${\wedge}$/), velopharyngeal function (/m/), and labial function (/p${\wedge}$/). The Aerophone II was used for data recording. The results of finding as follows: average fast ab/adduction rates were vocal function(6.21cps), tongue function(7.42cps), velopharyngeal function(5.23cps), labial function (6.93cps). The results of this study are guidelines of normal diadochokinetic rates. In addition, they can indicate the severity of diseases and evaluation of treatment.

• 말소리와 음성과학
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• 제2권4호
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• pp.193-212
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• 2010

The purpose of our study was to provide effective speech evaluation items examining the variables of speech that successfully predict the speech intelligibility in CP children. The subjects were 55 children with spastic type cerebral palsy. As for the speech evaluation, we performed a speech subsystem evaluation and a speech intelligibility test. The results of the study are as follows. The evaluation task for the speech subsystems consisted of 48 task items within an observational evaluation stage and three levels of severity. The levels showed correlations with gross motor functions, fine motor functions, and age. Second, the evaluation items for the speech subsystems were rearranged into seven factors. Third, 34 out of 48 task items that positively correlated with the syllable intelligibility rating were as follows. There were four items in the observational evaluation stage. Among the nonverbal articulatory function evaluation items, there were 11 items in level one. There were 12 items in level two. In level three there were eight items. Fourth, there were 23 items among the 48 evaluation tasks that correlated with the sentence intelligibility rating. There was one item in the observational evaluation stage which was in the articulatory structure evaluation task. In level one there were six items. In level two, there were eight items. In level three, there was a total number of eight items. Fifth, there was a total number of 14 items that influenced the syllable intelligibility rating. Sixth, there was a total number of 13 items that influenced the syllable intelligibility rating. According to the results above, the variables that influenced the speech intelligibility of CP children among the articulatory function tasks were in the respiratory function task, phonatory function task, and lip and chin related tasks. We did not find any correlation for the tongue function. The results of our study could be applied to speech evaluation, setting therapy goals, and evaluating the degree of progression in children with CP. We only studied children with the spastic type of cerebral palsy, and there were a small number of severe degree CP children compared to those with a moderate degree of CP. Therefore, when evaluating children with other degrees of severity, we may have to take their characteristics more into account. Further study on speech evaluation variables in relation to the severity of the speech intelligibility and different types of cerebral palsy may be necessary.

• 한국컴퓨터정보학회논문지
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• 제21권12호
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• pp.131-137
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• 2016

In this paper, the peak finding algorithms corresponding to the Autocorrelation Function (ACF), which are widely exploited for detecting the pitch of voiced signal, are proposed. According to various researchers, it is well known fact that the estimation of fundamental frequency (F0) in speech signal is not only very important task but quite difficult mission. The proposed algorithms, presented in this paper, are implemented by using many characteristics - such as monotonic increasing function - of ACF function. Thus, the proposed algorithms may be able to estimate both reliable and correct the fundamental frequency as long as the autocorrelation function of speech signal is accurate. Since the proposed algorithms may reduce the computational complexity it can be applied to the real-time processing. The speech data, is composed of Korean emotion expressed words, is used for evaluation of their performance. The pitches are measured to compare the performance of proposed algorithms.

• ETRI Journal
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• 제32권2호
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• pp.345-347
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• 2010

In this letter, we present a new speech hash function based on the non-negative matrix factorization (NMF) of linear prediction coefficients (LPCs). First, linear prediction analysis is applied to the speech to obtain its LPCs, which represent the frequency shaping attributes of the vocal tract. Then, the NMF is performed on the LPCs to capture the speech's local feature, which is then used for hash vector generation. Experimental results demonstrate the effectiveness of the proposed hash function in terms of discrimination and robustness against various types of content preserving signal processing manipulations.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권1호
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• pp.92-96
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• 2001

Velopharyngeal function refers to the combined activity of the soft palate and pharynx in closing and opening the velopharyngeal port to the required degree. In normal speech, various muscles of palate & pharynx function as sphincter and occlude the oropharynx from the nasopharynx during the production of oral consonant sounds. Inadequate velopharyngeal function caused by neurologic disorder - cerebral apoplexy, regressive diseases - disseminated sclerosis, Parkinson's disease, congenital deformity - cleft palate, cerebral palsy and etc. may result in abnormal speech characterized by hypernasality, nasal emission and decreased intelligibility of speech due to weak consonant production. In our study, we constructed speech aids prosthesis - Palatal lift in acquired idiophathic VPI patient and assessed velopharyngeal function with various diagnostic instruments which can evaluate the speech characteristics objectively.

• 음성과학
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• 제12권4호
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• pp.17-29
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• 2005

Time-frequency representation reveals some useful information about instantaneous frequency, instantaneous bandwidth and boundary of each AM-FM component of a speech signal. In many cases, the instantaneous frequency of each component is not constant. The variability of instantaneous frequency causes degradation of resolution in time-frequency representation. This paper presents a method of adaptively adjusting the transform kernel for preventing degradation of resolution due to time-varying instantaneous frequency. The transform kernel is the form of frequency modulated function. The modulation function in the transform kernel is determined by the estimate of instantaneous frequency which is approximated by first order polynomial at each time instance. Also, the window function is modulated by the estimated instantaneous. frequency for mitigation of fringing. effect. In the proposed method, not only the transform kernel but also the shape and the length of. the window function are adaptively adjusted by the instantaneous frequency of a speech signal.

• 말소리와 음성과학
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• 제15권3호
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• pp.45-52
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• 2023

Previous studies have established a role for cognitive differences in explaining variability in speech processing across individuals. In the case of perceptual cue weighting in the context of a sound change, studies have produced conflicting results regarding the relationship between executive function and the use of redundant cues. The current study aimed to explore this relationship in acoustic cue weighting during speech production. Forty-one Korean-speaking children read a list of stop-initial words and completed two tests that assess executive function, i.e., Dimensional Change Card Sorting (DCCS) and digit n-back. Voice onset time (VOT) and fundamental frequency (F0) were measured in each word, and analyses were carried out to determine the extent to which children's executive function predicted their use of both informative and less informative cues to the three pairs comprising the Korean three-way stop laryngeal contrast. No evidence was found for a relationship between cognitive ability and acoustic cue weighting in production, which is at odds with previous, albeit conflicting, results for speech perception. While this result may be due to the lack of task demands in the production task used here, it nevertheless expands the empirical ground upon which future work in this area may proceed.

• 음성과학
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• 제3권
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• pp.57-69
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• 1998

Velopharyngeal function refers to the combined activity of the soft palate and pharynx in closing and opening the velopharyngeal port to the required degree. In normal speech, during the production of oral consonant sounds elevation of the soft palate, along with the superior constrictor muscle, occludes the oropharynx from the nasopharynx. Inadequate velopharyngeal function caused by congenital or acquired insufficiency or incompetency may result in abnormal speech characterized by hypernasality, nasal emission and decreased intelligibility of speech due to weak consonant production. The speech aid is often helpful in improving the speech of individuals with velopharyngeal incompetency. In this article, the pathogenesis and treatment of velopharyngeal incompetence are discussed and a speech aid appliance that was constructed for the patient is described.

• 말소리와 음성과학
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• 제1권3호
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• pp.95-102
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• 2009

In this paper, an efficient target speech detection algorithm is proposed for the performance improvement of multi-input speech enhancement. Using the normalized cross correlation value between two selected channels, the proposed algorithm estimates the probabilistic distribution function of the value from the pure noise interval. Then, log-likelihoods are calculated with the function and the normalized cross correlation value to detect the target speech interval precisely. The detection results are applied to the generalized sidelobe canceller-based algorithm. Experimental results show that the proposed algorithm significantly improves the speech recognition performance and the signal-to-noise ratios.