• Speech Sciences
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• v.3
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• pp.93-108
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• 1998

This paper attempts to acoustically examine the place of articulation of Korean affricates. In order to pursue an acoustic analysis of where Korean affricates are articulated, we resort to LPC spectra of the Korean plain affricate /c/ in intervocalic position, based on theoretical assumptions (e.g., Stevens 1993a), and compare the data to that of the Korean alveolar consonants /t, s/ in the same context. Our phonetic results show that in intervocalic position, the Korean plain affricate is alveolar just like the Korean alveolar consonants /t, s/, supporting the articulatory studies of $Skali{\check{c}}kov{\acute{a}}$ (1960) and Kim (1997).

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.795-798
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• 2000

연속음 인식과 음성 합성을 위해서는 정밀한 음성학적 모델과 연속 음성에 적용 가능한 언어 모델의 개발이 중요하다. 이를 위해서는 음성 데이터 베이스에 대한 인식 단위, 혹은 합성 단위의 분할이 필요한데, 수동음성 분할은 일관성의 유지가 어렵고 긴 시간이 소요되므로 최근에는 자동 분할 기술이 많이 연구되고 있다. 자동 음성 분할 기법으로는 시간 영역이나 주파수 영역특징 벡터의 천이를 분석하는 방법과 특징 벡터간의 상관도를 구하여 경계를 추출하는 방법이 있다. LPC smoothed log amplitude spectra는 음성의 주파수 영역의 특징을 잘 나타내며, 동일 음소 내의 상관도가 서로 다른 음소의 상관도보다 더 크고, 음소의 경계구간에서 급격한 상관도의 변화를 보인다. 이 특성을 이용하여 이웃 프레임에 대한 상관도의 방향성이 특정조건을 만족하는가를 검사하여 음소의 경계를 구하는 방법을 찾았다. 또한 LPC. 이득 인자만으로 묵음 구간을 검출하는 방법을 제시한다. 이렇게 하면 묵음 구간검출과 음소 경계 검출의 일관성을 향상시키고 수행 시간을 단축시킬 수 있다. 제안한 기법으로 허용 오차 20ms 이내에서 연속음성에 대한 음소 경계 검출 실험을 수행한 결과, 수작업으로 행한 경계 검출 지점의 약 88%를 정확히 검출하였다.

• The Journal of the Acoustical Society of Korea
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• v.31 no.3
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• pp.179-187
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• 2012

This paper presents a novel method for estimating reliable noise spectral magnitude for acoustic background noise suppression where only a single microphone recording is available. The proposed method finds noise estimates from spectral magnitudes measured at line spectral frequencies (LSFs), under the observation that adjacent LSFs are near the peak frequencies and isolated LSFs are close to the relatively flattened valleys of LPC spectra. The parameters used in the proposed method are LPC coefficients, their corresponding LSFs, and the gain of LPC residual signals, so it suits well to LPC-based speech coders.

• Speech Sciences
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• v.10 no.4
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• pp.137-147
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• 2003

Speech synthesis can classify by synthesis way, that is waveform coding, source coding and mixture coding. Specially, waveform coding is suitable for high quality synthesis. However, it is not desirable by synthesis techniques of syllable or phoneme unit because it do not separate and handles excitation and formant part. Therefore, there is a need for pitch alteration method applied in synthesis by the rule in waveform coding. This study propose about pitch alteration method that use spectrum scaling after do to flatten spectra by subband linear approximation to minimize spectrum distortion. This paper show evaluation whether show excellency of some measure compared with LPC, Cepstrum, lifter function and method that propose. estimation method seeks distribution of each flattened signal and measured degree of flattened spectra Signal flattened is normalized, So that highest point amounts to zero, and distribution of signal ,whose average is zero, is calculated. this show result that measure the spectrum distortion rate to estimate performance of method that propose. The average spectrum distortion rate was kept below the average 2.12%, so the method that propose is superiors than existent method.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.746-751
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• 1991

Deafs train articulation by observing mouth of a tutor. sensing tactually the notions of the vocal organs, or using speech training aids. Present speech training aids for deafs can measure only single speech ter, or display only frequency spectra in histogrm or pseudo-color. In this study, a speech training aids that can display subject's articulation in the form of a cross section of the vocal organs and other speech parameters together in a single system Is aimed to develop and this system makes a subject to know where to correct. For our objective, first, speech production mechanism is assumed to be AR model in order to estimate articulatory notions of the vocal tract from speech signal. Next, a vocal tract profile mode using LPC analysis is made up. And using this model, articulatory notions for Korean vowels are estimated and displayed in the vocal tract profile graphics.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.2
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• pp.101-106
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• 2008

The speech signal has been put into a form suitable for storage and analysis by computer, several different operation can be performed. Filtering, sampling and quantization are the basic operation in digiting a speech signal. The waveform can be displayed, measured and even edited, and spectra can be computed using methods such as the Fast Fourier Transform (FFT), Linear predictive Coding (LPC), Cepstrum and filtering. The digitized signal also can be used to generate spectrograms. The spectrograph provide major advantages to the study of speech. So, author introduces the basic techniques for the acoustic recording, digital signal processing and the principles of spectrum and spectrogram.

• Journal of Korean Society of Forest Science
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• v.97 no.2
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• pp.156-164
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• 2008

Recognizing the importance of the multi-purpose management of natural deciduous forest, this study was carried out to implement the partial cutting for stand regulation to examine agroforestry practice as well as other concurrent forest resource production, and to investigate the changes in stand characteristics and understory vegetation in a silvopasture practiced natural deciduous stand in the Research Forest of Kangwon National University, Korea. Three different partial cutting intensities (68.1%, 48.6%, and control) were performed in the unmanaged natural deciduous stand in order to improve the growing condition, especially light condition, for introducing some commercial herbaceous plants on the forest floor to establish agroforestry and/or silvopastoral system. Dominated by Quercus varibilis Blume (50.5%) and Quercus dentata Thum. ex Murray (42.6%), eight tree species were composed of the study forest, including poles of Pinus desiflora Siebold & Zucc and sapling of Pinus Koraiensis Siebold & Zucc. The total of 87 (13 tree species, 12 shrub species, 58 herbaceous species, and 4 woody climbers) vascular plant species were observed in study site after partial cutting treatments, while that of before partial cutting was 53 species (14 tree species, 8 shrubs species, 30 herbaceous species, and 1 woody climbers). The proportion of life form spectra in plot B was Mi (28.4%)-Na (23.0%)-Ge (17.5%)-Ch (10.8%)-He (9.5%)-MM (6.7%)-Th (4.1%). No statistically significant differences were observed in changes of life form spectra from before to after partial cutting treatment and among partial cutting gradients in this study. Partial cutting and scratching for forage sowing made plants invade easily on the forest floor, and light partial cutting (LPC) plot (500 stems/ha) had much higher number of undersory species than those of heavy partial cutting (HPC) plot (310 stems/ha) and control plot (1,270 stems/ha).

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.134-135
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• 1993

The purpose of this research is development of EGG system for quantitative assessment of laryngeal function using speech and electroglotto-graphic data. The designed EGG system is 4-electrodes system which excitation current source is supplied from 1st to 4th electrode. The output signal.: from 2nd and 3rd electrodes, which are motivated by frequency of excitation current source, are air-pressure waveforms from vocal folds. After demodulation process, we obtain pitch signals of the modulated waveforms by excitation current source through differentiator which cuts off frequency below 0.1Hz. Software processing methods were used as conventional pitch extraction methods, but the proposed system is designed to analog hardware in order to eliminate interferences from low formant frequency of speech. We will construct the discriminating database between pathological subjects and control groups on each case. Using the proposed 3 channel EGG system and LMS algorithm, it will be detected that the distinctive characteristics of laryngeal function of voiced region and other regions by EGG signals and LPC spectra.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.4
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• pp.23-27
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• 2010

This paper performs emotion classification test to find out the best parameter of electroencyphalogram(EEG) signal. Linear predictor coefficients, band cross-correlation coefficients of fast Fourier transform(FFT) and autoregressive model spectra are used as the parameters of 10-channel EEG signal. A multi-layer neural network is used as the pattern classifier. Four emotions for relaxation, joy, sadness, irritation are induced by four university students of an acting circle. Electrode positions are Fp1, Fp2, F3, F4, T3, T4, P3, P4, O1, O2. As a result, the Linear predictor coefficients showed the best performance.