• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.354.1-354
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• 2002

Pitch is a perception related to frequency, one of the psychological aspects or attributes of tones, and an important factor to determine sound quality of sound together with loudness and timber. while a study on pitch has been actively achieved In the part of speech recognition and speech separation, that for analysis and improvement of product sound quality is not yet enough. (omitted)

• 한국기계가공학회지
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• 제10권4호
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• pp.22-30
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• 2011

This study analyzes harmonic vibration with natural frequency according to the configuration of damper clutch. In the case of double spring, equivalent stress at same direction of the revolution at inner and outer coil spring is over 30% as compared with at its opposite direction. Natural frequency or harmonic response with maximum deformation in case of the less coil pitch is below 3Hz as compared with in case of the more coil pitch. As the coil pitch of damper spring as the case 2 or 4 becomes smaller, its mass and deformation can be large. In these cases, spring constant and natural frequency become smaller. In the case 5 or 6 of double spring at natural vibration or harmonic response, the frequency becomes over 300Hz. As the result of this study is applied by the design of damper spring, the damage at its connected part is prevented and the durability can be predicted.

• 한국음향학회지
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• 제10권4호
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• pp.12-18
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• 1991

음성 신호처리 분야에서 기본주파수를 정확히 검출하는 것이 아주 중요하다. 주파수 영역에서 피치검출 방법의 문제점은 대체로 배경잡음이나 제 1 포먼트에 의하여 발생한다. 그러므로, 본 논문에서는 스펙트럼 AMDF 함수를 이용하여 잡음의 영향이나 제 1 포먼트의 영향을 줄이는 주파수영역 피치검출 앨고리즘을 제안하였다. 여러 가지 컴퓨터 시뮬레이션 결과 제안한 앨고리즘이 기본주파수 검출에 효과적으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1610-1614
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• 1987

The harmonies of the fundamental frequency in speech signal make a minute line spectrum in frequency domain. In this paper, we propose a new algorithm to detect a pitch interval in voiced sound based on the fact that the number of harmonies can represent the period of the pitch in the time domain.

• 음성과학
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• 제10권2호
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• pp.7-25
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• 2003

Predicting the right prosodic elements is a key factor in improving the quality of synthesized speech. Prosodic elements include break, pitch, duration and loudness. Pitch, which is realized by Fundamental Frequency (F0), is the most important element relating to the quality of the synthesized speech. However, the previous method for predicting the F0 appears to reveal some problems. If voiced and unvoiced sounds are not correctly classified, it results in wrong prediction of pitch, wrong unit of triphone in synthesizing the voiced and unvoiced sounds, and the sound of click or vibration. This kind of feature is usual in the case of the transformation from the voiced sound to the unvoiced sound or from the unvoiced sound to the voiced sound. Such problem is not resolved by the method of grammar, and it much influences the synthesized sound. Therefore, to steadily acquire the correct value of pitch, in this paper we propose a new model for predicting and classifying the voiced and unvoiced sounds using the CART tool.

• Ocean Systems Engineering
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• 제8권1호
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• pp.79-99
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• 2018

The effects of BPC (blade pitch control) on FOWT (floating offshore wind turbine) motions and generated power are investigated by using a fully-coupled turbine-floater-mooring simulation program. In this regard, two example FOWTs, OC4-5MW semi-submersible FOWT and KRISO four-3MW-units FOWT, are selected since the numerical simulations of those two FOWTs have been verified against experiments in authors' previous studies. Various simulations are performed changing BPC natural frequency (BPCNF), BPC damping ratio (BPCDR), and wind speeds. Through the numerical simulations, it was demonstrated that negative damping can happen for platform pitch motions and its influences are affected by BPCNF, BPCDR, and wind speeds. If BPCNF is significantly larger than platform-pitch natural frequency, the pitch resonance can be very serious due to the BPC-induced negative-damping effects, which should be avoided in the FOWT design. If wind speed is significantly higher than the rated wind velocity, the negative damping effects start to become reduced. Other important findings are also given through systematic sensitivity investigations.

• 한국음향학회지
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• 제21권3호
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• pp.310-314
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• 2002

음성인식, 합성 및 분석과 같은 음성신호처리 분야에 있어서 기본주파수 즉, 피치를 정확히 검출하는 것은 중요하다. 그러나 포만트의 영향과 천이진폭의 영향 때문에 음성신호로부터 정확한 피치검출은 매우 어렵다. 따라서 본 논문에서는 음소의 천이나 변동의 영향이 적은 주파수 영역에서 스펙트럼을 평탄화함으로써 포만트의 영향을 제거한 후 피치를 검출한다. 본 논문에서는 새로운 스펙트럼 평탄화 기법을 제안하고 기존의 방법인 LPC법, 켐스트럼법과 비교하여 어느 정도의 우수성을 보이는지 평가하였다. 또한 각각의 방법을 적용하여 기본주파수 (피치)를 검출한 결과는 제안한 방법이 우수함을 보여주고 있다.

• 한국도로학회논문집
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• 제19권5호
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• pp.97-106
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• 2017

PURPOSES: This study aims to evaluate the effects of vehicle dynamic behaviors on ride quality. METHODS : Simulation and field test were conducted to analyze the behavior of a driving vehicle. The simulation program CarSIM was applied and an INS (Inertial Navigation System) was used for field experiments. A small simulator was developed to simulate vehicle behavior such as roll, pitch, and bounce. The panels evaluated the ride quality in five stages from "very satisfied"to "very dissatisfied."Experiments were conducted on a total of 144 cases of vehicle behavior combinations. RESULTS :In both simulation and field tests, pitch is the largest and yaw the smallest. Especially in the field test, the amount of yaw is very low, about 7% of pitch and 18% of roll. The sensitive and extensive analysis conducted related ride quality with changing the frequency and amplitude. It was found that the most sensitive frequency range is 8 Hz across all amplitudes. Moreover, the combination of the roll and bounce was most sensitive to the ride quality at the low-frequency range. CONCLUSIONS : This result show that the vertical vehicle behavior (bounce) as well as the rotational behavior (roll and pitch) are highly correlated with ride quality. Therefore, it is expected that a more reasonable roughness index can be developed through a combination of vertical and rotational vehicle behavior.

• 융합신호처리학회논문지
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• 제9권2호
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• pp.159-163
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• 2008

본 논문에서는 유연모드 부속물을 갖는 우주선의 제어를 위해서 누스범 이득을 갖는 간단한 형태의 적응제어기를 제안한다. 이 방법은 전달함수에서 고주파 이득의 정보가 필요하지 않는다. 본 논문의 방법을 사용하여 피치각도가 목표치를 추종하는 중에, 아울러 유연모드의 안정화도 이룬다. 피치각과 피치각속도 성분만 사용하여 출력궤환제어기를 설계한다. 특히 모든 시스템 파라미터 및 고주파성분은 미지로 한다. 설계의 간편성을 위해서 선형함수만을 사용하여 설계한 제어기가 전체 비선형시스템을 만족함을 시뮬레이션을 통하여 보이고, 그 근거도 설명한다. Lyapunov 함수를 구성하여 제안한 방법의 안정성을 증명하고, MATLAB을 이용한 컴퓨터 시뮬레이션 결과를 제시하여 제안한 방법의 유용성을 증명한다.

• 한국음향학회지
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• 제29권1호
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• pp.41-47
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• 2010

음성변환을 위한 피치변경법은 시간영역법과 주파수영역법, 혼성영역법이 많이 사용되고 있으며 시간-주파수 혼성영역법은 스펙트럼 왜곡이 적고 명료성과 자연성이 우수하다는 장점이 있는 반면 영역변환을 위한 처리시간이 매우 길다는 단점을 가지고 있었다. 본 논문에서는 시간-주파수 혼성 영역 피치변경법의 처리시간을 단축하는 방법을 제안하였다. 음성신호를 켑스트럼으로 변경하는 과정에서 사용되는 FFT와 IFFT의 비트-재정렬 과정을 생략함으로써 처리시간을 단축하는 방법이다. 이를 적용함으로써 기존의 켑스트럼 피치변경법과 같은 음성품질을 유지하면서도 처리시간은 86.26%로 단축할 수 있었다.