• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.11 no.5
• /
• pp.83-88
• /
• 2001

The sound absorption coefficient of glass wool (bulk density of 48 kg/m:1 and 32 kg/m7) 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/.7-octave band and while noise, gives similar values.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.939-944
• /
• 2002

Recently Korean Industrial Standards has been revised and established newly accordance with the ISO system, especially ISO 140 series. This study aims to introduce and review ISO 11654 which contents rating of sound absorption, and then this study suggests to establish appropriate evaluating method and Korean Industrial Standard of the sound absorber for use in building.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.163-164
• /
• 2014

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.393.2-393
• /
• 2002

In this study, the ISO 15186-1 "Measurement of sound insulation in buildings and of building elements using sound intensity - Part 1 Laboratory conditions" was reviewed in order to make it as a new Korean Insustrial Standard. Several main contents are discussed and a new Korean Korean Insustrial Standard is proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.354.1-354
• /
• 2002

Pitch is a perception related to frequency, one of the psychological aspects or attributes of tones, and an important factor to determine sound quality of sound together with loudness and timber. while a study on pitch has been actively achieved In the part of speech recognition and speech separation, that for analysis and improvement of product sound quality is not yet enough. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.675-680
• /
• 1997

The object of this study is the numerical analysis about the sound pressure distribution in reverberation rooms. In order to obtain the effect of the boundary conditions of the wall, the sound field was computed for various absorption coefficients and impedances. And the effect of the room shape was investigated by dealing with pentagonal type as well as the rectangular type. In addition an experiment was performed for the sound pressure distribution in a reverberation room and the result was compared with the analysis.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.702-706
• /
• 2009

Internal running noise of a vehicle running in open field is the summation of air borne noise and structure-borne noise. In this paper vibration damping characteristics of carbody are investigated to see the effect of sound-deadening paint on the internal running noise. By using SEA method, vibration levels of complete train with and without sound-deadening paint are estimated and structure borne noise levels are estimated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.184-190
• /
• 2003

In this study, several methods for measuring floor impact sound were introduced. Among them, the simple methods (impedance method and diffuse index method) which can be easily applied to site works were investigated. Moreover, the comparison between the calculation results using diffuse index method and the experimental results measured in real apartment structures was conducted. Consequently, the modified diffuse index method, which can be practically used for predicting the performance of to the floor impact sound of apartment structures and can meet the allowable tolerance of Grade I (${\pm}$5㏈), was proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.383-386
• /
• 2005

Low frequency heavy-weight impact noise is the most irritating noise in Korean high-rise reinforced concrete apartment buildings. This low frequency noise is generated by foot traffic due to the fact that Koreans do not wear shoes at home. The transmission of the noise is facilitated by a load bearing wall structural system without beams and columns which is used in these buildings. In order to control low frequency heavy-weight impact noise, floating floors using isolation materials such as glass-wool mat and poly-urethane mat are used. However, it was difficult to control low frequency heavy-weight impact sound using isolation material. In this study, reinforcement of concrete slab using beams and plate was conducted. Using the FEM analysis, the effect of concrete slab reinforcement using FRP(fiber-glass reinforced plastic) on the bang machine impact vibration acceleration level and sound were conducted at the standard floor impact sound test building. The $3{\sim}4dB$ floor impact vibration acceleration level and impact sound pressure level were reduced and the natural frequency of slabs were changed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.275-278
• /
• 2005

In this study, the dynamic properties of a floor impact sound isolation pad expressed in terms of the natural frequency, the dynamic stiffness per unit area and the loss factor are measured by the resonant method. By using the measured dynamic properties, the vibration transmissibility diagram is obtained for each isolation pad, which is compared with the values tested by the impact sound sources at the room in an apartment. From the comparative results, it is found that the noise reduction Performances. of isolation pads are closely connected with the natural frequency and the dynamic stiffness per unit area.