• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.133-137
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• 2007

As the waterpower generation plant, the subject of this Study, is a facility that produces plenty of electricity corresponds to $196{\sim}240GWh$ annually, and in its generation process it creates a loud noise when the turbine related to the hydraulic turbine dynamo revolves, and since such loud noise must be transmitted to the dynamo room and amplified, it is effecting a lot of influences to the adjacent office and space. In such viewpoint, this Research, based on the soundproof measure presented at the preceding research, has attempted to evaluate about the effect of noise-reduction countermeasure against the hydraulic turbine dynamo using Auralizational Technique through Psycho-Acoustics Experiment. It deems that such result could be applied hereafter as the useful material when setting up a soundproof countermeasure for the hydraulic turbine dynamo room in dam.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.248-252
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• 2007

As Waterpower Generation generates electricity using the difference of altitude of water, also let the turbine revolves through water pipe, at this time the revolving turbine causes exceedingly huge noise. Accordingly, not only those workers in the hydraulic turbine dynamo room are suffering the difficulties in mutual communication, but also those workers in the adjacent office are enduring the obstruction to the business due to the noise. Therefore, this Study has analyzed the reduction effect on the noise of hydraulic turbine dynamo room utilizing computer simulation, through the preceding research with the optimized model for architectural acoustic factor of the hydraulic turbine dynamo room. It is considered that such research result could be applied as the useful material for improvement of acoustic performance and noise-reduction effect at other similar hydraulic turbine dynamo room in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.641-645
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• 2002

저소음 팬의 설계는 팬 성능의 저감 없이 이루어져야 한다. 따라서 저소음 팬 설계는 기본적으로 다분야간 설계 최적화 또는 다목적 설계 최적화의 문제이다. 본 연구에서는 이러한 요구를 수행하기 위해 반응면 기법을 저소음 축류 팬 설계에 적용하여 보았다. 또한 이러한 설계 단계에서 필요한 수백가지 시험 결과를 효과적으로 구하기 위해 효율적인 유동 해석 툴과 소음 해석 툴을 개발하여 적용시켰다. 마지막으로 이렇게 설계된 팬을 실제 크기로 제작 측정 비교 분석하여 적용된 기법을 검증하며 문제점에 대해 고찰해 보았다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.423-426
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• 2007

In this paper, vibration reduction of resiliently mounted machinery and effect of the foundation impedance is studied. SBN (Structure-borne noise) reduction through the mount is analyzed by assuming that the system is modeled as a mass-spring system, while the impedance of the floor is included in the prediction. The comparison of the SBN difference through the mount between predictions and measurements show that the slopes are similar in the case of single-mount system, while the measurements differs significantly from the predictions in the case of the double-resilient system.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.119-125
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• 2000

In this study, field measurements and analysis of vibration before and after the installation of continuously welded rail were performed. The vibration data obtained at the same locations before and after were analyzed to find out the characteristics of vibration level. The component of train-induced impulsive vibration at the rail joints varies depending upon the distance from the source, however mostly low frequency vibration which propagates long distance causes the problems of vibration. Even though it is expected that there may be certain degree of discrepancy in the amount of reduction in vibration depending upon site ground conditions, it was found that installation of continuously welded rail shows reduction in train-induced vibration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1350-1354
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• 2000

철도 소음에 의한 환경문제가 증가하고 있으나 방음대책으로는 아직까지 방음벽을 철도 연변에 설치하는 것인데 이러한 방음벽은 주위 경관과의 부조화와 열차승객의 시아방해 등으로 높이에 제한을 받는다. 높이를 높이지 않고도 저감효과를 얻을 수 있는 방음벽과 상단형상의 개발이 중요한 연구과제로 대두되고 있다. 본 논문에서는 철도연변에 설치되는 방음벽의 종류별로 삽입손실을 ISO 10847에 근거하여 측정하였으며 그 결과를 상호 비교 분석 평가하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.113-118
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• 2012

본 논문은 실험적 방법을 통한 소음기의 개발과정 및 개발품의 성능평가에 대한 연구결과이다. 개발의 목적은 현재 적용된 외산 블로어 소음기의 국산화이며 이에 위해 적용 블로어의 허용 Spec.과 목표적감량 및 기 적용 소음기의 성능을 기준으로 개발 목표를 설정하였다. 또한 제작성을 고려한 내부 설계안을 선정, Shop Test를 실시하여 Test 결과에 따라 최적설계안을 확정하였다. 최종 개발품은 56mmAq의 정압손실과 23dB 이상의 소음저감효과를 가지고 있다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.417-418
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• 2014

This study examined the effect of children's indoor shoes how much they can reduce floor impact sound in the apartment. Four types of specimen were produced and tested when children aged under nine years old jumped and found some of them can reduce maximum 9 dB compared with when the children jumped without shoes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.693-697
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• 2014

본 연구는 민원인(아래층)과 피민원인(윗층)간 전문상담사의 중재를 통해 층간소음 문제를 해결하는 층간소음 현장관리시스템의 실효성을 검증하였다. 민원인(아래층)과 피민원인(위층)의 층간소음 피해경향을 분석한 결과, 4,087건 중 80%에 해당하는 3,254건의 민원인들은 층간소음 발생장소를 바로 윗층을 지목하는 것으로 나타났고, 반면에 15%에 해당하는 피민원인들(윗층)은 피해를 받는 원인이 소음이 아니라 피민원인의 전화나 방문 등을 통한 잦은 항의를 지적하는 것으로 분석되었다. 1,304건의 현장 방문 민원건수 중 80%에 해당하는 1,050건을 대상으로 현장방문 컨설팅 전 후의 층간소음 저감 등 만족도 조사결과, 약 683건에 해당하는 65%정도의 민원인은 층간소음 현장관리시스템에 만족하고 있는 것으로 평가되었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.447-453
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• 2012

Nowadays, high speed train has settled down as a fast and convenient environment-friendly transportation and it's need is gradually increasing. However increased train speed leads to increased aerodynamic noise, which causes critically affects comfortability of passengers. Especially, the pantograph of high speed train is protruded out of train body, which is the main factor for increased aerodynamic noise. In this research, to reduce aerodynamic noise pantograph, panhead's shape changed to aerodynamical shape. aerodynamic noise of pantograph is predicted by CFD (Computational Fluid Dynamic) and FW-H (Ffowcs Williams-Hawkings) equation. Also, the sound pressure level of aerodynamic noise of base and modified models are predicted. And the reduction effects of the sound pressure level is analyzed.