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정행진(Hang-jin Jung),서충열(Chung-youl Seo) 한국자동차공학회 2000 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-
The major effective factor on the inner noise of a bus are the structure borne noise and air borne noise. Engine contributes about 80% of the vibration and noise in the vehicle, and exciting forces of the engine are transmitted onto the body through the rubber mount.<br/> This apper aims to investigate the characteristics of engine room walls are insulated, such as<br/> multi layer walls of engine room.<br/> Six kinds of compartment walls are varied with materials and multi layer, depth. Acoustics<br/> characteristics of these partitions, transmission loss, are tested in reverberation chambers.
구진회(Gu, Jin-Hoi),이재원(Lee, Jae-Won),서충열(Seo, Chung-Youl),장성기(Jang, Seong-Ki),최경희(Choi, Kyung-Hee),한진석(Han, Jin-Seok) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.3
The noise emitted from an excavator has long been a cause of environmental disputes, while causing displeasure to the nearby residents. So, the ministry of environment adopted the construction machinery noise labeling system to encourage the construction machinery manufacturing companies to develop the low noise construction machinery voluntarily. But, as the quality of life improves, a growing number of people desire the comfortable and quite environment to live in. Under the situation, noise from the construction machinery has been a major cause for stress and complaints. When the noise dispute happened in the construction site, the sound pressure level of the construction machinery like a excavator was measured at the lot boundary of the noise victim's residence to judge how much noise damage occur. But the sound pressure level of the construction machinery is measured differently according to the acoustic environment of construction site and the measuring position, respectively, which makes it difficulty to judge whether the noise damage occur or not. As the sound power level of noise source is not affected by the acoustic environment of construction site and the measuring position, if we use the information of the sound power level, it will be easy to judge whether the noise damage occur and to establish the soundproofing measures. Therefore, we derive the sound power level regression model of the excavator to judge whether the noise emitted from the excavator damages to residents near the construction site. Also, the sound power level regression model of the excavator drawn in this paper will help construction companies to plan the noise reduction program in the construction sites.
구진회(Gu, Jin-Hoi),이재원(Lee, Jae-Won),이우석(Lee, Woo-Seok),최경희(Choi, Kyung-Hee),서충열(Seo, Chung-Youl),박형규(Park, Hyung-Kyu),김삼수(Kim, Sam-Soo),한진석(Han, Jin-Seok) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.9
The global warming caused the changes of our environment like an increasing tropical night phenomenon in the middle latitude areas. Especially, in Korea, the habitats of tropical Korean blockish cicada have changed from Jeju island located in Southern part of Korea to the whole of Korea because of the increasingly warming weather. The cicadas crying sound have been social problem because the tropical Korean blockish cicadas cry at middle of the night owing to the various outdoor lights. The cicada is positive phototaxis insect. So, the cicada is not cry at night. But if the outdoor light is very bright, then the cicada confuse the night as a day and start to cry. As a result, the cicadas crying noise has caused the resident living in downtown to an unpleasure and sleeplessness. In this research, we have measured three kinds of cicada singing noise at 16 points of urban area(Incheon, Gwangju, Busan, Gyeonggido Anyang). And then we analyzed the sound quality of the three kinds of cicada singing noise using by CADA-X signal process program. And we analyzed the acoustical characteristics by STFT(short time Fourier transform) which is a time-frequency analysis method. The characteristics of the cicada singing noise in terms of the sound quality and the time-frequency variation will be usefull to discover the relations between the human annoyance about the cicada singing noise and the acoustical characteristics.