• The Journal of the Acoustical Society of Korea
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• v.17 no.8
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• pp.82-87
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• 1998

음성합성은 합성방식에 따라 파형부호화법, 신호원부호화법, 혼성부호화법으로 분류 할 수 있다. 특히 고음질 합성을 위해서는 파형부호화를 이용한 합성방식이 적합하다. 그렇 지만, 파형부호화를 이용한 합성법은 여기 성분과 여파기 성분을 분리하지 않고 처리하기 때문에 음절단위나 음소단위의 합성기법으로는 바람직하지 못하다. 따라서 파형부호화법을 규칙에 의한 합성에 적용되도록 음원피치를 변경시키기 위한 피치 변경법이 필요하게 된다. 본 논문에서는 스펙트럼 왜곡을 최소화하기 위해 켑스트럼의 성질을 이용하여 피치를 변경 하는 방법에 대하여 제안하였다. 이 방법은 주파수영역상에서 여기 스펙트럼과 여파기 스펙 트럼을 분리하여 여기 스펙트럼을 여기 켑스트럼으로 변환한 후 영값 삽입이나 삭제에 의해 피치를 변경하고 스펙트럼영역에서 피치 변경된 스펙트럼을 재구성하는 기법을 적용하였다. 제안한 방법의 성능을 평가하기 위해 스펙트럼 왜곡율을 측정하여 본 결과 평균 스펙트럼 왜곡율은 평균 2.29%이하로 유지되었으며 주관적인 음질도 평균 3.74로 우수하였다.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.217-220
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• 2000

일반적으로 고음질 음성합성을 하기 위해서는 합성음의 지속 시간을 변경하여 줌으로써 운율을 조절하는 기법이 필요하다 이에 먼저 고음질용 음성부호화법을 선정하여야 하고 정확한 피치와 피치시점검출을 통해서 음원분류가 되어야한다. 본 논문에서는 제안한 자동 피치시점 검출을 적용해서 운율조절에 필요한 지속시간 조절 법을 제안하고자 한다. 제안한 방법은 시간영역에서 직접 처리하기 때문에 피치동기분석이 용이하고 다른 영역으로의 변환과정이 불필요하다. 결과적으로 파형부호화법을 적용하고 제안한 자동 피치서점 검출에 의한 지속시간 조절법을 적용하였을 때 비교적 우수한 결과를 얻을 수 있었다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.489-492
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• 2002

최근 인간형 로봇에 대한 개발이 괄목할 만한 성장을 이루고 있고, 친근한 로봇의 개발에 중요한 역할을 담당하는 것으로써 감성/감정의 인식이 필수적이라는 인식이 확산되고 있다. 본 논문은 음성의 감정인식에 있어 가장 큰 부분을 차지하는 피치의 패턴을 인식하여 감정을 분류/인식하는 시뮬레이터의 개발과 실험결과를 나타낸다. 또한, 피치뿐 아니라 음향학적으로 날카로움, 낮음등의 요소를 분류의 기준으로 포함시켜서 좀더 신뢰성 있는 인식을 할 수 있음을 보인다. 시뮬레이터의 내부 구조로는 음성으로부터 피치를 추출하는 부분과 피치의 패턴을 학습시키는 DRNN 부분, 그리고, 음향적 특성을 추출하는 음향 추출부가 주요 요소로 이루어져 있다. 그리고, 피치를 추출하는 방법으로는 Center-Clipping 함수를 이용한 autocorrelation approach를 사용하고, 학습 시 최적의 개체를 찾는 방법으로써 (1+100)-ES를 사용한다.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.36-42
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• 2020

In order to investigate the effect of the oxidation process on thermal properties of the pitch, the oxidized pitch was prepared by changing the oxidation temperature. Thermal properties of the pitch were analyzed using thermogravimetric analysis (TGA), and it divided into three sections as A (25~100 ℃), B (250~550 ℃) and C (550~800 ℃) by derivative thermogravimetry (DTG) graph behavior. In the A section, the was reduced because the moisture contained in the pitch was removed. In the B section, as the oxidation temperature increased, the thermal stability of the pitch is improved. Because the degree of aromaticity and molecular weight of the pitch increased with increasing oxidation temperature. In contrast, the results of the C section were shown opposite of B section. Because the introduced C-OH, C-O-C, and C=O bonds were decomposed, and the resulting oxygen compounds induced the combustion reaction of the pitch.

• The Journal of the Acoustical Society of Korea
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• v.23 no.1
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• pp.61-74
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• 2004

In this paper, a contort- and speaker-dependent cepstrum extraction method and a channel normalization method for minimizing the loss of speaker characteristics in the cepstrum were proposed for a robust speaker recognition system over the channel. The proposed extraction method creates a cepstrum based on the pitch synchronous analysis using the inherent pitch of the speaker. Therefore, the cepstrum called the 〃pitch synchronous cepstrum〃 (PSC) represents the impulse response of the vocal tract more accurately in voiced speech. And the PSC can compensate for channel distortion because the pitch is more robust in a channel environment than the spectrum of speech. And the proposed channel normalization method, the 〃formant-broadened pitch synchronous CMS〃 (FBPSCMS), applies the Formant-Broadened CMS to the PSC and improves the accuracy of the intraframe processing. We compared the text-independent closed-set speaker identification on 56 females and 112 males using TIMIT and NTIMIT database, respectively. The results show that pitch synchronous km improves the error reduction rate by up to 7.7% in comparison with conventional short-time cepstrum and the error rates of the FBPSCMS are more stable and lower than those of pole-filtered CMS.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.213-220
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• 2016

This research aims to develop core technologies for passive carrier (no power in carrier itself) transfer system. The technologies are passive levitation, propulsion, and guidance, which can be great benefits for semiconductor and display manufacturing industries. Passive maglev carrier is necessary to precise position control for quiet and stable transfer operation. However, the structural characteristics of carrier and the installation errors of gap sensors cause the pitch motion. Hence, the controller design in consideration of pitch motion is required. This study deals with the reduction control of carrier pitch motion. PDA controller and PDA controller with pitch control are proposed to compare the pitch angle analysis. The pitch angle and the levitation precision are measured by experiment. Finally, the optimized design of pitch controller is presented and the effects are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2893-2899
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• 2009

The study classified speech styles of shopping hosts and tried to examine how the classified speech styles have an effect on the evaluation of shopping hosts and the purchase intentions. In the evaluation of speech styles of shopping hosts, except customer-oriented confutative style, credibility, descriptive relevance, other speech styles are analyzed to have an impact on the styles. When we investigate the influential relations between speech styles proved by a theory and the evaluation of shopping hosts, the demonstrative style comes first, the expressive style is next and the descriptive follows in terms of influential power. In terms of the purchasing intention, speech styles of shopping hosts have an effect on the demonstrative and expressive types rather than the elucidative and descriptive ones. Namely, the analysis shows that the speech style which is logically persuasive and expresses the contents in detail is preferred to the descriptive and leading speech style.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.94-104
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• 2013

A numerical analysis has been conducted to determine the pitch thrust vectoring characteristics of a two-dimensional convergent divergent exhaust nozzle for supersonic aircraft application. The numerical analysis was done by using Fluent and verified by the experimental test results. Analysis was performed with pitch angle of $0^{\circ}$ and $20^{\circ}$ each at the ambient temperature condition. To see the effect of a ratio of pitch flap length and pitch flap height, the ratio was varied from 0.5 to 2.5. The numerical analysis shows that pitch thrust is changed greatly with pitch flap length. The big difference of the pitch thrust with pitch flap length is due to the shock interactions in the nozzle.

• Composites Research
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• v.33 no.6
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• pp.329-335
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• 2020

In this study, the thermo-rheological behaivors of petroleum pitches with different softening points were studied, and a B-stage phenolic resins/petroleum pitches blends were prepared by adding petroleum pitches to the phenolic resins. As a result, the petroleum pitch with different softening points decreased the fluidity of the petroleum pitch as the Quinoline insoluble (QI) content increased and showed the viscous properties of the solid. In addition, the effect of adding petroleum pitches having different softening points on the thermo-rheological properties of phenolic resins was investigated. When petroleum pitch with a high softening point was added, the fluidity of the phenolic resin was reduced, and the hardening behavior was fast. It was possible to control the curing rate and curing behavior of the phenolic resin by adding petroleum pitches of different softening points. Among them, the phenolic resin mixture to which P-Pitch 2 was added has a higher fluidity than other blends under the same curing temperature condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.23-28
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• 2006

Pitch period that is a important factor in speech signal processing is used in various applications such as speech recognition, speaker identification, speech analysis and synthesis. So many pitch detection algorithms have been studied until now. AMDF which is one of pitch period detection algorithms chooses the time interval from valley point to valley point as pitch period. In selection of valley point to detect pitch period, complexity of the algorithm is increased. So in this paper we proposed the simple algorithm using rotation transform of AMDF that detects global minimum valley point as pitch period of speech signal and compared it with existing methods through simulation.