• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.554-555
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• 2012

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.654-655
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• 2013

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.166-167
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• 2013

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.241-245
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• 2000

In this paper, VHF(30~230[MHz]) electromagnetic waves radiated from partial discharge(PD) at two-type electrodes in air are measured and the peculiar patterns of their spectra are reported. Also, the polarization and distance characteristics of electromagnetic wave rediated by PD, were investigated. In case of epoxy insulator in inserted, the noise level of radiated electromagnetic waves is 0.6~6.2[dB] higher than the case in air at below 90[MHz]. The frequency spectrum distribution of radiated electromagnetic waves appears different in the whole frequency range according to the arrangement of antenna.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.800-804
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• 2005

In this paper, the radiated sound pressure induced by low velocity impact is obtained by solving the Rayleigh integral equation. For structurally radiated noise, the sound field is directly coupled to the structural motion. Therefore the impact response should be analyzed. It is well known that the presence of the delamination in a composite laminate introduces a local flexibility which changes the dynamic characteristic of the structure. The 2-D simplified delamination model is used to analyze the impact response. And the 3-D non-linear finite element model is developed using gap element to avoid the overlap and penetration between the upper and lower sub-laminates at delamination region. Predicted impact response using 2-D equivalent delamination model are compared with the numerical ones from the 3-D non-linear finite element model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.407-408
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• 2014

본 논문은 3차원 수중방사패턴 예측을 위하여 수중구조물의 표면진동장을 이용하여 3 차원 원음장 패턴을 예측한 뒤 수중구조물의 근접음장 계측데이터를 활용하여 산출된 원음장 음향파워를 이용하여 산출된 원음장 패턴의 음압크기를 보정하였고 이를 실험데이터와 비교 분석한 논문이다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.629-634
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• 2004

Cavities are inevitable structures in automobile configuration. The flow-induced noise is generated from the wheel housing section by the interaction between a rotating wheel and the unsteady flows in the cavity. In this research the wheel housing was assumed by a rectangular cavity for simplification. We measured the radiated sound from the 2-D cavity without cylinder and from the rotating cylinder in the cavity by using the sound source localization method with an acoustic mirror system. In the 2-D cavity case of low Mach number(Ma=0.029), the sound sources were found to be located near the leading edge of cavity due to the shear layer instabilities. Comparing the cases of the rotating and the non-rotating cylinder, it is observed that the sound Pressure levels around the rotating cylinder in the cavity increased and the main acoustic sources were located at the rear section of the rotating wheel.

• 전자공학회논문지C
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• 제34C권1호
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• pp.51-58
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• 1997

In passive sonar, the frequency spectrum of a sound radiated by underwater moving targets is composed of a broadband nonuniform background noise and narrowband discrete tonals. To detect the tonals, the background noise is estimated and removed. Using the existing algorithms that estimate the background noise, a week tonals are not detected. Because a freuqency line that is formed by tonals which are being extracted continuously is a feture of the target, we are nessesory to efficiently detect the tonals that compose the frequncy line. In this paper, we propose an efficient neural network that can remove automatically the background and detect the even errl tonals, and we extract the frequency line feature on the spectrogram by the proposed algorithm. The experimental results for a ship's radiated sound show a better performance in comparison with the existing TPM algorithm.

• 한국소음진동공학회논문집
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• 제20권10호
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• pp.968-975
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• 2010

The high interest for the ground vibrations which is caused by the train service is risen. When the trains are passed, a serious force is applied to ground and the caused vibration is propagated to the area of the building by the ground and rocks. This vibration comes to feel in the residents with the direct vibration, it is radiated in sound. The caused vibration and radiated sound affect the human's life, and this vibration brings about the operation interruption of the equipment which is sensitive to the vibration, or will bring about the structural damage of the building. In this study, the effect of the vibrations caused by the passing trains on the railway station and buildings is investigated by vibration measurement. Indoor and outdoor measurement is carried out by each trains.

• 대한기계학회논문집A
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• 제36권7호
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• pp.789-796
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• 2012

함정의 수중방사소음은 그 해석의 어려움이나 정확성에 있어서 매우 관심이 큰 문제이다. 본 논문에서는 구조물의 수중방사소음을 해석하기 위하여 유한요소/경계요소 연성해석법을 제안하였다. 제안된 방법은 헤름홀츠방정식에 대한 Burton-Miller 적분방정식에 기반하는 부가수 질량과 감쇠행렬을 이용하여 구조물의 구조-유체 연성응답을 해석하고 계산된 구조물의 응답으로부터 수중방사소음을 계산하는 순차적인 방법이다. 구조-유체연성작용의 구조해석은 상용소프트웨어인 MSC/NASTRAN 에 구조-유체연성효과 행렬을 추가하여 해석하는 방법으로 이루어졌고, 수중방사소음의 경우는 전용 소프트웨어를 개발하였다. 개발된 수중방사소음 해석법을 간단한 예제를 통하여 그 특성을 살피고, 실제 함정의 받침대 진동에 의한 수중방사소음의 계산에 적용하여 그 유용성을 보였다.