• 말소리와 음성과학
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• 제7권2호
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• pp.85-94
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• 2015

This study is to investigate the characteristic of tonal elements in word utterance of 30 pre-school children. For the analyses, 240 utterances of 4 syllable words were processed to extract acoustic values and then the data was transformed into tonal height in order to examine the contour. The results show that the mean pitch of a note is $C4{\frac{1}{2}}(271.17Hz)$ and high and low pitched notes are $C5{\frac{1}{2}}(452.57Hz)$ and $G{\sharp}3{\frac{1}{2}}(192.54Hz)$. The pitch patterns of the 4 syllables measured at the frication and aspiration portion are $E4{\frac{1}{2}}-F4-B3{\frac{1}{2}}-A3$ and F4-E4-B3-A3. The pitch patterns of consonant clusters are $B3{\frac{1}{2}}-D4-B3{\frac{1}{2}}-A3{\frac{1}{2}}$ and $A{\sharp}3{\frac{1}{2}}-C4-A3-D4{\frac{1}{2}}$. The analyses of tonal elements in this study provide evidentiary data on tonal height helpful for developing melodic contour.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.154-157
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• 2005

Generally, noise from a indoor air conditioner has been measured by overall sound pressure level, dB. Customers evaluation, however, of the noise from an air conditioners should not be depend on the only overall level but also the sensory feeling. Moreover, in this sensory evaluation, irregular, time-varying and uneven sounds which are difficult to describe itself by overall level are more affectable. Unfortunately however the formal evaluation method for this kinds of noise is not determined yet. In this research, the evaluation method for tonal noise, which is one of the unmeasurable sounds by overall level, is proposed to evaluate its acceptability based on the consumer's sense of hearing. To consider the consumer's sense, several times of Jury evaluation are carried out. The proposed approach could be applied to the other sound, which acoustical characteristics are similar to the tonal noise .

• 말소리와 음성과학
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• 제5권4호
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• pp.137-143
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• 2013

Recent investigation of acoustic correlates of Korean stop manner contrasts has reported a diachronic transition in Korean stops: young Seoul speakers are relatively more dependent on the F0 characteristics of the stops than on the VOT characteristics in aspirated and lenis stop distinction. This finding has been examined against tonal dialects of Korean and the results suggested that the speakers of tonal dialects are not sharing the transition. These results also suggested that F0 function for segmental stop classification interferes with the function for lexical tone classification in their tonal speech. The current study investigated these findings in terms of perception. Perceptual behavior of Seoul and Busan speakers of Korean was examined in a comparative manner through the measurement of perceptual cue weight of F0 and VOT in particular. The results from regression and correlation analyses revealed that Busan speakers are closer to older Seoul speakers than to younger Seoul speakers in that the cue weight for VOT and F0 were comparable in the aspirated-lenis stop distinction. This result was in contrast to the perceptual behavior of younger Seoul speakers who showed clear dominance of F0 over VOT for the same distinction. These findings provided perceptual evidence of the dual function of F0 for segmental and lexical distinctions in tonal dialects of Korean.

• 대한기계학회논문집B
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• 제27권3호
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• pp.286-293
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• 2003

The unsteady flow characteristics and associated blade tonal noise of a cross-flow fan are predicted by computational methods. The incompressible Navier-Stokes equations are time-accurately solved for obtaining the pressure fluctuations between the rotating blades and the stabilizer. and the sound pressure is predicted using Curie's equation. The discrete noise characteristics of three impellers with a uniform and two random pitch (type-A and -B) blades are compared by their SPL (Sound Pressure Level) spectra. and the frequency modulation characteristics of the BPF (Blade Passing Frequency) noise are discussed. Besides. a mathematical model is proposed for the prediction of discrete blade tonal noise and is validated with available experimental data. The fan performance is also compared with experimental data. indicating that the random pitch effect does not significantly alter the performance characteristics at ${\phi}$ 〉 0.4

• 말소리와 음성과학
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• 제5권3호
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• pp.47-54
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• 2013

The purpose of this study is to analyse prosodic characteristics of accentual phrases (AP, hereafter) produced by Chinese learners of Korean in Korean text reading. The study is restricted only to the initial APs. Subjects are students who have been studying Korean at a beginner level. The results showed that Chinese learners of Korean tended to make errors in the realization of the tonal patterns of the initial 2 syllables of the initial APs. Also they showed different F0 slopes across the initial and second syllables in the initial APs. Chinese learners of Korean, therefore, need to focus on the prosodic characteristics of the initial 2 syllables of Korean APs to realize fluent Korean intonation.

• 한국멀티미디어학회논문지
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• 제6권5호
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• pp.816-823
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• 2003

이 논문에서는 토널 특성을 이용한 브라인드 오디오 워터마킹을 제안한다. 먼저 기존의 심리음향연구를 통해 토널의 인지영향에 대해 살펴보고, 토널 성분이 여러 신호처리 후 변동측면에서 매우 안정적인 특성을 가짐을 다른 워터마크에 이용되는 특성들과 비교하여 보였다. 이를 기반으로 토널 마스커를 구성하는 주파수 신호들의 관계를 이용한 브라인드 오디 오 워터마킹(blind audio watermarking) 기법을 제안하였다. 이 기법이 적용된 오디오에 대한 SDG(Subjective Diff-Grades) 음질평가에서 평균 SDG 0.27의 결과를 얻었고 이는 비지각성 면에서 토널의 인지 영향을 이용한 워터마킹이 유용하다고 볼 수 있다. 또한 time shift를 제외한 여러 신호처리 후의 워터마크 추출 결과는 98%이상으로 제안한 워터마킹의 강인성을 보였다. Time shift처리에 대해서는 시간 축 상에서 최적의 위치를 찾아 추출하는 새로운 방법을 적용하여 추출율 90%의 결과를 얻었다.

• 한국정보통신학회논문지
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• 제7권6호
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• pp.1123-1129
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• 2003

기동하는 잠수함이나 함정 등의 방사 소음 특성은 토날 신호와 광대역 배경잡음으로 구분될 수 있다. 토날 신호는 함정의 모터나 엔진 등의 회전으로 인해 발생하는 것이고, 광대역 배경잡음은 프로펠러에 의해 방사된 기포와 선체의 주위 물의 흐름 등으로 인해 발생하는 것이다. 이와 같은 기동함정의 방사 소음의 토날 신호와 배경 잡음을 분석하면 함정의 종류나 속도 등에 대한 정보를 분석할 수가 있다. 이 때 배경잡음의 세기가 토날 신호에 비하여 큰 경우는 토날 신호를 배경잡음으로부터 분리하기가 쉽지 않다. 본 연구에서는 ATW(Automatic Tracking Window) 전처리 알고리즘을 이용하여 방사 소음의 방향을 탐지하고, 표적 방향으로 배열 센서의 빔을 형하여 신호를 채취한다. 또한 ATW 알고리즘을 이용하여 이 신호에서 광대역 잡음에 섞여 있는 미약한 토날 신호를 분리할 수 있는 방법을 제시한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.158-163
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• 2005

In this paper the aeroacoustic characteristics of a tilt-rotor system is measured by using a sealed model tilt-rotor. With a microphone array system and the do-dopplerization algorithm, the location and the characteristics of rotor noise are successfully measured. The most of high frequency noise (4kHz) is found to be located at rotor blade tips, but the low frequency tonal noise is dominant on the middle of the rotor blades. The measured tonal noise characteristics are compared to the results of theoretical calculation. At 0.5m distance from the rotor plane, measured and calculated data are relatively well matched regardless of rotating speed and collective pitch angie for the azimuthal angles between $0^{\circ}\;and\;60^{\circ}$. However, the data on the azimuthal angles between $70^{\circ}\;and\;90^{\circ}$ are not quite comparable. In addition, the compared data for far-field case (1.5m) are quite different. This is probably due to the unsteady effect which if not included in the theoretical calculation.

• 한국주조공학회지
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• 제21권2호
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• pp.135-140
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• 2001

Microstructure of the bell made with Cu-Sn alloys was examined by optical and scanning electron microscope and that analyzed quantitatively with image analyzer. Also acoustic characteristics of the bells were measured in detail by using FFT type power spectrum analyzer. ${\alpha}-single$ phases of large grains only were observed in Cu-5%Sn alloy. However mixed structure of primary ${\alpha}-phase$ and eutectoid of ${\alpha}+{\delta}%_o$ was existed in the Cu-Sn alloys with more than 9%Sn. Also the area fraction of eutectoid phases gradually increased with an increased Sn content. From the result of acoustic test, it was found that frequency and tonal intensity decreased with the increased Sn content from 5%Sn to 11%Sn, and those were rather increased with further increase of that. The lowest frequency and tonal intensity were showed in Cu-11%Sn, and porosity decreased considerably frequency and tonal intensity of the bells.

• 한국가시화정보학회지
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• 제21권3호
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• pp.39-48
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• 2023

In this study, we investigate the effects of slots installed on the tip of a rotor blade on aerodynamic characteristics. The slots weaken the strength and spatial coherence of the tip vortex at early vortex age and accelerate the dissipation of the generated tip vortex. Accordingly, the turbulence intensity of the rotor wake is reduced at both near and far wake, which leads to a reduction in broadband noise. Tonal noise is also reduced by mitigation of tip vortices, but tonal noise reduction is limited to a narrower range of azimuths than broadband noise due to the extinction of tip vortices. In addition, slots reduce both mean thrust and thrust fluctuations. Reduction in thrust fluctuations leads to a reduction in blade loading noise, resulting in a reduction in tonal noise.