• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.762-765
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• 2005

The absorption materials have been used to enhance the performance of a noise barrier and improve the room acoustics. In this study, 6 products of absorptive materials generally used in Korea were chosen, and their absorption performance were tested in various conditions, that is, it was measured while changing thickness, density and air gap in their back, and measured with or without facing on their face. Finally, the absorption coefficients were compared by reverberation and impedance tube method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.509-512
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• 2004

규준화 바닥충격음레벨 평가시 잔향시간은 흡음력 보정을 위해서 필수적으로 고려해야 할 사항이다. 그러나, 잔향시간의 측정 편차가 심하기 때문에 이로 인해 규준화 바닥충격음레벨이 5dB 이상씩 변동하는 경우가 생긴다. 잔향시간 측정 편차의 원인은 실의 형상에 따른 고유모드 분포로 설명할 수 있으며, 측정시 계측기에서의 원인, 특히 동특성에 따라 측정 편차가 심하다는 것을 실험을 통해 알 수 있었다. 또한, 잔향곡선은 직선적인 형태일 경우에 정확한 측정이 가능하나, 저주파수 대역에서는 잔향곡선에 요철이 많이 생기므로 측정 데이터들을 이용하여 잔향시간을 산출할 때 세심한 주의가 요구된다.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.53-58
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• 2003

Now days, as the consideration of sound environment is getting important, method of physical measurement such as reverberation time and sound pressure level becomes common. However, such method cant include subjective sensation such as personal emotion and feeling, evaluation. So there is a limitation to make the most optimized sound environment. Therefore, in the present experiment, I improve big indoor gymnasium that has sound defect because of too long reverberation time. After that, I conduct the auditory sense evaluation of human psychological response. From the experiment, I will make research into sound satisfaction rate about the subject space and response of each item. As well as, I will present the result as basic database of sound environment improvement experiment of indoor gymnasium.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.10-12
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• 2014

In ISO 10140-5:2010, defines the reverberation time conditions of the receiving room. The sound absorption side of test specimen is installed in the source room generally. In this study, examined at the change in the sound insulation characteristics for the test specimen of asymmetric structure attached sound absorbing material by changing the installed position. A difference of sound insulation performance was maxium Rw 1 dB, it is preferable to place the larger sound absorption area in source room.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.622-625
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• 2006

This study is a fundamental investigation for standardization of the heavy-weight floor impact measuring method by the impact ball. The distribution chrematistics of floor impact sound level and reverberation time in a receiving room of the testing building for floor impact sound were measured with variations of number and arrangement of the sound-absorbing materials. Total 8 cases were investigated. The distribution of the floor impact sound level($L_{i,\;Fmax}$) was measured at 30 points with same intervals. The absorption coefficient of the room is 0.10 in case of installation of 6 absorbing materials and 0.02 in case of non-installation. The distribution shape of the impact sound pressure level was similar to the result of the bang machine driving at the measured frequency range. However, the overall reduction of the impact sound level investigated in the 125 to 500 Hz shows that the sound absorption characteristics of the receiving room actually affects the result of the heavy-weight impact measurement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.715-719
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• 2007

Recently, since there appear the quality improvement in both educational and cultural level at the college campus also, thus the lecture room is requiring by the students where the intimacy degree among the students can be raised, also a smoother interaction between the professor and the student is able to be generated. Particularly in case of College of Music, the Practical Technique Training Rooms such as Orchestral Music Room, Pipe Music Concert Room, Music-Part Practice Room are more important for the interaction between Professor and Student or Student attends at the lesson, than the lecture rooms of any other colleges. Likewise, while such music practice room should be designed with consideration of the acoustic characteristics, so as to obtain the feel as if hear it performs at a music hall, but since the most of music practice room was designed with consideration of the convenience of construction work and its economical efficiency only, it has been exposed with many acoustic defects after the completion of construction. Therefore in this thesis, it has grasped the physical acoustic characteristics on the object of the two orchestral music rooms, pipe music concert room and ensemble practice room, among the newly constructed practice rooms of the Music College, W University, and it is considered that it could be utilized as the fundamental data on the base of this material when designing of the college music practice room, for the future.

• Journal of KSNVE
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• v.7 no.6
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• pp.945-952
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• 1997

This paper shows the feasibility of the suggestion that the angle distribution of incident sound to panels might be gaussian, instead of the conventional uniform distribution in the analysis of transmission loss of panels. To prove the suggestion, the problems with the diffuse sound field in a reverberation room are examined by case studies and the comparision of the prediction with the measurement of sound transmission loss of walls are performed. The results of the comparision show good agreement between the two values.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.643-649
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• 1998

This paper is to compare the absorption coefficient with normal incidence waves and it with diffuse incidence waves of glass wool which the most used absorption material and multi layer fiber. The absorption coefficient with normal incidence waves is calculated by surface impedance that measured by using an acoustic tube. Based on this data, the absorption. coefficient with diffuse incidence waves is predicted and is compared with measured the absorption coefficient in reverberation room.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1070-1076
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• 2001

In this study, the room acoustics of a hall in Kimhae Performing Arts Center is discussed. The hall is designed as a multi-purpose hall. The reverberation time of the hall is varied by absorptive/reflective surfaces. A design method using both objective and subjective evaluations is investigated. As a result, the geometrical shape and the interior materials are determined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.185-190
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• 2000

The sound absorption coefficient of glass wool (bulk density of 48 kg/$m^3$ and 32 kg/$m^3$) was measured by reverberation room method as varying their cross-sectional area. The results show that the absorption is larger for smaller samples because of edge effect. The absorption coefficient with two different kinds of sources, 1/3-octave band and white noise, gives similar values.