• 음성과학
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• 제5권1호
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• pp.63-80
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• 1999

In this paper, an adaptive method of dividing a speech signal into an initial, a medial and a final sound of the form of utterance utilized by evaluating extreme limits of short term energy and autocorrelation functions. By applying this method into speech signal composed of a consonant, a vowel and a consonant, it was divided into an initial, a medial and a final sound and its feature analysis of sample by LPC were carried out. As a result of spectrum analysis in each period, it was observed that there existed spectrum features of a consonant and a vowel in the initial and medial periods respectively and features of both in a final sound. Also, when all kinds of words were adaptively divided into 3 periods by using the proposed method, it was found that the initial sounds of the same consonant and the medial sounds of the same vowels have the same spectrum characteristics respectively, but the final sound showed different spectrum characteristics even if it had the same consonant as the initial sound.

• 한국멀티미디어학회논문지
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• 제9권7호
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• pp.801-807
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• 2006

본 연구는 국악기 피리의 소리합성을 위한 기초 단계로, 피리의 음색 특징을 분석하였다 분석은 세 가지로 나누어 첫째, 피리의 음색 특징을 스펙트럼 분석을 통하여 오보에와 비교하였고, 둘째, 피리 소리들의 어택(attack)부분의 시간대별 분석을 통하여 소리 발생과정에 따른 음색을 분석하였으며, 마지막으로 악기연주의 중요한 역할을 하는 비브라토의 특성을 분석해 보았다. 그 결과 피리 음색은 서양악기와 달리 높은 배음들의 음량이 높게 나타났고, 소리발생 초기단계(어택 부분)에서는 노이즈 양이 급격히 줄어드는 것과 반하여 배음들의 음량 값이 높아졌으며, 비브라토에서도 음량위주로 변화하는 서양악기와 달리 음고와 음량이 동시에 변화한다는 특성을 알 수 있었다. 이러한 배음에 따른 음색 특징과 소리 발생과정에서의 음색변화, 그리고 비브라토에서의 음고와 음량 변화는 피리의 독특한 음색을 잘 나타내 주는 특징들로써 소리합성에 있어서 반드시 적용되어져야 할 것이다.

• International Journal of Advanced Culture Technology
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• 제8권4호
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• pp.287-293
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• 2020

More and more people are paying attention to the psychological pleasure and relaxation that sound hearing brings. In most cases, humans seem to have a special preference for natural sounds. Natural sounds are mainly white noise and pink noise such as wind, rain, waves, waterfall sounds, etc. All of these are often considered to be beneficial to human health, but in reality the same category of natural sounds is no different. It will be very different due to space, time and other factors. Each sound can be unique, so people's hearing experience is also different. This paper quantitatively analyzes the spectrum and brain waves to analyze the feeling of hearing the natural Broken Falls sound. In particular, we aim to objectively analyze the objective feeling of Broken Falls sound falling on the human auditory system through sound spectrum and brain waves.

• 대한의용생체공학회:의공학회지
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• 제10권2호
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• pp.151-156
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• 1989

본 연구에서는 폐 및 기관지 질환 환자에 대한 객관적인 진단을 위한 폐음분석 시스템을 설계하였다. 적응 필터링 기법에 의하여 순수한 폐음을 분리하였고 이의 power spectrum을 구하기 위하여 TMS320C25 DSP 칩과 IBM PC를 사용해서 폐음 분석기를 구성하였다. 실험결과 적응 격자 위너 필터는 10차의 적은 차수로도 분리가 가능하였고 정상 폐음은 100-200 Hz, 급성 섬유성 폐렴폐음(crackle)은 100-400 Hz, 기관지 협착증(wheeze)폐음은 150-600 Hz에서 주파수범위를 갖는 power spectrum의 양상을 통해 각각 패턴 분류할 수 있었다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.752-757
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• 1994

Very often, one would like to have visual image of mechanical or acoustical events such as musical sound and transient vibrations. Conventional methods to visualize the signal, such as power spectrum, do not normally allow to cultivate the signal of interests due to their inherent limitation on transient signals. Other than the conventional method, one could use an instantaneous frequency which can reveal the variation of frequency in terms of time. Nevertheless it is quite sensitive to noise and can not resolve the frequency components of signals; normally produces additional components other than those of the signals. In this paper, we introduce the Wigner-Ville spectrum to see the transient characteristics of signal, especially musical sound and transient mechanical vibration signatures. For musical sound, several popular western classic music have been selected for the analysis. For the transient mechanical signature, the signals obtained from the car door experiment and the beam experiment are interpreted in terms of Wigner-Ville spectrum. Results demonstrate the visual expressions of transient signals; musical sound and vibrations.

• The Journal of the Acoustical Society of Korea
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• 제25권3E호
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• pp.89-94
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• 2006

For audio indexing and targeted search of specific audio or corresponding visual contents, the MPEG-7 standard has adopted a sound classification framework, in which dimension-reduced Audio Spectrum Projection (ASP) features are used to train continuous hidden Markov models (HMMs) for classification of various sounds. The MPEG-7 employs Principal Component Analysis (PCA) or Independent Component Analysis (ICA) for the dimensional reduction. Other well-established techniques include Non-negative Matrix Factorization (NMF), Linear Discriminant Analysis (LDA) and Discrete Cosine Transformation (DCT). In this paper we compare the performance of different dimensional reduction methods with Gaussian mixture models (GMMs) and HMMs in the classifying video sound clips.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1113-1116
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• 2003

In this paper, it is suggested that the technology sound measurement which is to search the inferiority of the plate during the pressing. We evaluate whether there is a inferiority by analysing and comparing the satisfactory and inferior plate with the method of a spectrum analysis by measuring the sound which is emitted during pressing. We designed the analysis algorithm to detect inferior plate throughout comparison of measured sound data using FFT, DFT and DASYLab S/W. In addition to these, we suggest the way to compare both inferior and satisfactory signal statistically.

• International Journal of Advanced Culture Technology
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• 제9권2호
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• pp.123-129
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• 2021

When shaving, it is easy to suffer shaving burns, that is, facial burn irritation during shaving. The reason is that the razor blade irritates the skin. The current solution is to make the razor sharper and use a razor with a blade heating function. Although these ways can increase the comfort of shaving, they will also greatly increase shaving costs. This paper proposes using a hairdryer to massage the skin before shaving to reduce skin irritation during shaving. This is a simple, practical and low-cost method. The hair dryer's heat, sound, and wind energy have a massage effect, and they can make shaving easier and more comfortable. For analyzing shaving effect, two evaluation methods are used, which are sound spectrum analysis and mos. The sound spectrum analysis is used to analyze the working status of the razor objectively. The MOS test can reflect the subjective feelings of the subject on the shaving's comfort. The results show that the hairdryer thermal vibration massage can make the beard easier to cut, thereby reducing the irritation of the razor to the skin and improving shaving comfort.

• 정보처리학회논문지B
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• 제17B권1호
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• pp.69-78
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• 2010

스펙트럴 모델링 합성 (Spectral Modeling Synthesis, SMS)은 뮤지컬 사운드 모델링을 위한 강력한 툴로써 사용되어 왔다. 이 기술은 사운드를 결정적 (deterministic) 성분과 통계적 (stochastic) 성분의 조합으로 간주한다. Deterministic 성분은 크기 (amplitude), 주파수 (frequency), 위상 (phase) 함수에 따른 사인파의 연속으로 표현되는 반면, stochastic 성분은 백색 잡음 (white noise)으로 자극된 시간 변화 필터로서 동작하는 크기 스펙트럼 엔블로프 (spectrum envelop)의 연속으로 표현된다. 이러한 표현들은 원음의 모든 지각적인 특징들을 활용해 합성된 사운드를 구현 가능케 한다. 하지만, 고래 소리와 같은 복잡한 사운드에 대해 기존의 SMS를 사용할 때 연속적인 프로임에 있는 부분 주파수가 다른 경우 결정적 성분에서 상당한 위상 변화가 발생한다. 왜냐하면 기존의 SMS는 사운드의 결정적 성분을 합성하기 위해서 계산된 위상을 이용하기 때문이다. 그 결과 기존의 SMS는 높은 주파수 영역에서 원래 스펙트럼과 합성된 스펙트럼 사이에서 좋은 스펙트럼 매칭을 제공하지 못한다. 이러한 문제를 해결하기 위해 본 논문은 수정된 SMS를 제안한다. 제안하는 SMS는 결정적 성분을 합성하기 위해 원래 주파수 정보를 이용할 뿐만 아니라 주파수 영역에서 복잡한 잔재 (residual) 스펙트럼을 계산함으로써 원음과 합성음 사이에서 좋은 스펙트럼 매칭을 제공한다. 다양한 고래 소리 합성을 모의 실험한 결과, 제안된 방법은 시간 및 주파수 영역에서 기존의 SMS와 유사한 성능을 보였다. 하지만, 제안된 방법은 기존의 SMS보다 스펙트럼 매칭에서 더 좋은 성능을 보였다.

• ETRI Journal
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• 제37권4호
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• pp.824-832
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• 2015

Heart sounds are the main obstacle in lung sound analysis. To tackle this obstacle, we propose a diagnosis algorithm that uses singular spectrum analysis (SSA) and frequency features of heart and lung sounds. In particular, we introduce a frequency coefficient that shows the frequency difference between heart and lung sounds. The proposed algorithm is applied to a synthetic mixture of heart and lung sounds. The results show that heart sounds can be extracted successfully and localizations for the first and second heart sounds are remarkably performed. An error analysis of the localization results shows that the proposed algorithm has fewer errors compared to the SSA method, which is one of the most powerful methods in the localization of heart sounds. The presented algorithm is also applied in the cases of recorded respiratory sounds from the chest walls of five healthy subjects. The efficiency of the algorithm in extracting heart sounds from the recorded breathing sounds is verified with power spectral density evaluations and listening. Most studies have used only normal respiratory sounds, whereas we additionally use abnormal breathing sounds to validate the strength of our achievements.