• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1083-1087
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• 2001

The purpose of this study is to obtain the basic data of existing light-weight Drywall through the evaluation and analysis of the light-weight drywall in reverberation chamber and to improve sound insulation performance of drywalls. Sound transmission loss of the total 11 types were analyzed in each frequency a-third octave band and evaluated sound insulation performance for each frequency. From data by analysis and calculation, STC value plotted on STC contour. We found that the improved light-weight drywall specimens ⓑ, ⓒ and ⓖ were satisfied with the domestic standard of sound transmission loss.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.93-96
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• 2004

In the case of the front door of the apartment, which functions as an entrance, the study about noise has been less active than corridor type plane in the past, since stair room type plane was generalized. Hence, this study shows the survey about residents' thoughts of noise transmission through the front door, and after researching sound insulation of the present apartments, we figured out what the problem is. Moreover, we did an efficiency test as developing the front door, which increases sound insulation. As a result, it turned out that residents think that the noise transmission through the front door is as serious as floor impact noise, and also, the efficiency of the front door is as poor as STC 22-30. Therefore, in the developed front door, we should improve the efficiency to the level of STCSS. It will be a good way preparing for a demand of residents.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.209-212
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• 2002

This article introduce Comfort Class V released by Dnv The Class has an objective of classifying ships by noise and vibration levees. It is apparent that noise criteria listed in the Class can not be satisfied without special efforts to enhance sound insulation performance in cabins. Accordingly, panel makers should develope panels which have very high sound insulation performance enough to satisfy the criteria. Also, due to large difference of sound insulation performance between cabin and laboratory, it is necessary that ship yards should improve the method for installing cabins.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.421-424
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• 2000

This paper investigates the characteristics of analytical models in prediction of sound transmission loss for the multi-layered panels with high density mineral wools. The results show that the sandwich model is more adequate to account for sound insulation performance of those panels than the poro-elastic model. In order to improve STC(Sound Transmission Class), the effect of fiber directions of mineral wools is examined, analytically and experimentally. From the comparison of the measurements with the predictions, it is evident that the vertical fiber directions of mineral wools enhance STC value up to 6 dB, compared to that of the horizontal fiber directions.

• 대한조선학회논문집
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• 제59권6호
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• pp.362-371
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• 2022

As considerable interests in noise emission from the ships have been increased, International Maritime Organization (IMO) standardized the Underwater Radiated Noise (URN) measurement process of commercial ships in deep seas by enacting the related ISO standard ISO 17208-1 and classification societies responded with the enactment or revision of corresponding notations. According to this trend, a new hybrid underwater sound propagation model based on underwater sound propagation theories was developed and its accuracy on analysis was verified through the result comparison with the results of other generally used models. Using the verified model, each URN propagation characteristics adjusted by the correction methods proposed in the ISO standard and class notations were analyzed and compared in two assumed URN measurement cases. The results showed that the effects of transmission loss corrections in the circumstances with less bottom reflections generally similar but they had rather large differences in the model analysis results with bottom-reflection-dominant conditions. It was concluded that the deep consideration of effective bottom-reflection-correction method should be made in future revisions of ISO standard and class notations.

• 한국통신학회논문지
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• 제33권3C호
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• pp.234-239
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• 2008

For the efficient coding and transmission, the speech signal can be classified into three distinctive classes: voiced, unvoiced, and transition classes. At low bit rate coding below 4 kbit/s, conventional sinusoidal transform coders synthesize speech of high quality for the purely voiced and unvoiced classes, whereas not for the transition class. The transition class including plosive sound and abrupt voiced-onset has the lack of periodicity, thus it is often classified and synthesized as the unvoiced class. In this paper, the efficient algorithm for the transition class detection is proposed, which demonstrates superior detection performance not only for clean speech but for noisy speech. For the detected transition frame, phase information is transmitted instead of magnitude information for speech synthesis. From the listening test, it was shown that the proposed algorithm produces better speech quality than the conventional one.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.374.1-374
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• 2002

The eventual purpose of this research is to make optimum standards for acoustic-environment by using not only physical characteristics but also subjective appraisals. First, basic Physical data were measured which were necessary to establish standards for acoustic environment in campus buildings, TSP has used to measure sound levels, reverberation times, clearness indexes, and speech-transmission-index. (omitted)

• 한국음향학회지
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• 제36권5호
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• pp.329-337
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• 2017

미국과 영국에서는 교실의 적정한 음환경을 제공하기 위하여 잔향시간 및 배경소음에 대한 기준이 수립되어 있다. 또한 이를 실현하기 위한 건축계획방법 및 실내마감재 적용에 대한 가이드라인을 제시하고 있다. 그러나 대한민국의 경우 학교 교실의 배경소음 기준을 만족하기 위한 가이드라인이 부족할 뿐만 아니라 이에 기초가 되는 교실 벽체의 차음성능에 대한 실태조사가 부족한 실정이다. 본 연구에서는 학교 교실의 실내외 소음에 대한 차음성능을 조사하기 위하여 대한민국 청주시 소재 중학교 2개소의 외부벽체와 실간벽체의 구조를 조사하였다. 실내외 벽체의 차음성능 및 측로전달소음을 비교분석하기 위하여 투과손실, 가중 표준화 음압레벨차, 음향 감쇠 계수, 신호대잡음비 등을 측정하였다. 연구결과 실간벽체의 경우 건식벽으로 건립된 학교의 차음성능이 습식벽보다 높게 나타났으며, 특히 중고파수대역에서 높은 차음성능을 나타내었다. 외부벽체의 경우 각 학교 별로 차음성능을 비교하였을 때 단창을 이중으로 배치한 학교보다 복층유리를 사용한 학교의 성능이 더 높은 것으로 나타났다. 또한 측로전달소음의 경우 창문을 모두 개방하거나 복도 측 창문과 문을 연 경우 기준을 초과하는 것으로 나타나 내부 소음에 의해 학생이 음성전달에 방해를 받을 수 있음을 알 수 있었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.326-331
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• 2011

Aluminum extruded panel used in a high speed train shows high stiffness, however, its sound insulation performance is remarkably decreased by local resonance phenomena. In this paper, improvement strategy of the sound insulation performance is proposed for the floor extruded panel used in HEMU-400x, 400km/h class next generation high speed train under development, and the improvement effect is verified by experiment. Aluminum extruded panel specimen for the floor is manufactured and urethane foam is installed in the core of the panel. Based on ASTM E2249-02, intensity transmission loss is measured and the improvement effect in local resonance frequency band is verified. Finally, improvement effect of the sound insulation performance is estimated on the layered floor structure including the foamed aluminum panel.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.116-118
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• 2014

A shape optimization problem is formulated to optimally design aluminum sandwich panel, which is used for high speed railway vehicle. An aluminum volume used in the panel is selected as a design objective with constraints on the stiffness and the transmission loss value. The formulated shape optimization problem is solved for a well -selected initial shape. The stiffness and transmission loss value of the obtained optimal shape are compared with those of the previously-reported panel.