• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.196-201
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• 2006

In general, the vertical vibration problems for strength of members and serviceability of building structures are not considered in structural design process, but the prediction of the vertical vibration is very important and essential to structural design process. This study aims to investigate the characteristics of vertical vibration in terms of the transfer of horizontal directions on the rahmen building structures and the shear wall building structures. In order to examine the characteristics of vertical vibration, the modal test and the heel-drop excitation experiments were conducted several times on the two type building structures. The results from the experiments are analyzed and compared with the results. The results of this study suggest that the characteristics of vortical vibration transfer in horizontal way are effected from the fundamental frequency of the slabs and excitation forces and are effected the shear wall on the path of the vibration transfer.

• Journal of KSNVE
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• v.10 no.5
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• pp.859-864
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• 2000

An effective and new method of reducing the noise of a HDD by structural modification of cover was investigated in this study. The correlation between the noise characteristics of the HDD and the vibration characteristics of the cover, which is the main source of the HDD noise, is found from experiments. A theoretical analysis is performed to find the modification method of the cover, and this modification method is applied the real cover of the HDD. The modification reduces the vibration of the cover transferred from driving motor. The effect of the modification is verified through noise tests.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.132-137
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• 2000

Recently, a severe noise problem was encountered during a shop test of large scale vertical motor. In order to identify the noise characteristics and propose the countermeasure, a variety of experiments such as sound excitation test and contribution analysis was earned out in addition to ordinary noise and vibration measurements. The results showed that the severe noise level was dominated by an acoustic resonance phenonmenon in the cooler housing and higher sound power of outer fan. Through proper treatments, the noise level could be acceptable.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.2
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• pp.160-165
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• 2010

As the various industrial machinery has come into being by development of industrial technology, the productivity of the basic industrial machinery has improved. However, at the same time, noise from various industrial machinery disturbs the quiet environment. There are 35 kinds of the noise emission machinery defined in the noise and vibration control act according to the horse power and the number of machinery. These were classified in 1992, and the characteristics of the noise emission machinery may be different from the past one. So we need to investigate the characteristics of the noise emitted by machinery to control it rightly. We measured sound intensity of 32 noise emission machinery to calculate the sound power levels of those and investigated the characteristics of the sound power level of those according to the frequency. We found that the forging machine, concrete pipe and pile making machine, sawing machine, etc. are noisy. The generator, the concrete pipe and pile making machine, etc. emit the low frequency noise, but the molding machine, the stone cutter, the metal cutter, etc. emit the high frequency noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.992-995
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• 2006

In this Paper the noise characteristics of KTX are analyzed in order to study the interior noise mechanism of KTX in slab tracks, which has become an issue since the commercial operating in 2004. The analysis of the interior noise of KTX in tunnel with concrete track shows sharply increased noise level in the range of 80Hz that is the natural frequency of the KIX carbody. The frequency characteristics of noise and acceleration levels of KTX in tunnels are compared to understand the interrelation between the noise inside the vehicle and outside the vehicle in the slat track tunnel. As a noise abatement method, the mud-flap was modified with intend to reduce the noise outside gangway and the interior noise inside the passenger compartment ultimately. The effect of this mud-flap modification on the interior noise is introduced and discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.169-174
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• 2012

Reduction unit is one of the most important components for railway vehicle because torque of motor must be transmitted to wheels of vehicle by reduction unit. However, According to advanced studies, it has been often broke down due to the damage, fatigue and wear of gear. To solve this problem, defect diagnosis methods of gear have been mainly using the vibration diagnosis technology through vibration waveform and frequency analysis. However, We should know vibration characteristics of normal state reduction unit prior to defect diagnosis. So in this paper, We had analyzed vibration characteristics of reduction unit in order to utilize monitoring system development. Comparison of targets is the vibration characteristics of normal state reduction unit about Electric Multiple Unit(EMU) and the High-speed trains(KTX, KTX II).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.254-257
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• 2005

Locations and emission characteristics of noise source of rapier loom are important factors greatly. So, noise characteristics of rapier loom were investigated by the noise source identification as a part of experimental methods in this study. To identify the noise sources of the rapier loom sound intensity was measured under machine operation. In addition, frequency spectra of the sound at operator position was measured along with sound intensity to help identify the noise characteristics of the rapier loom. The results indicate that the sound power level occurs along the rapier loom.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.73-76
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• 2005

Recently, the demand for the Floating, Production, Storage, and Offloading facility (FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. FPSO vessel dose not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise sources such as gas turbines, compressors, and pumps, are located on top of the hull (Topside area). In general, the noise regulation for the offshore structure is severer than that of the cargo ship and acceptable noise limit of cabin is specified as 45 dB(A). This paper describes the noise characteristics and the countermeasures for FPSO Topside area through investigation of noise analysis and site measurement results. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various measurement results. Finally, this ship was successfully delivered with excellent noise properties.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.396.1-396
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• 2002

The AVT under traffic-induced vibrations was carried out on Namhae Suspension bridge in Korea. Mode shapes as well as natural frequencies up to the 15th mode were acquired exactly, and the effect of traffic mass and temperature on measured natural frequencies was investigated. The results from the AVT are compared with those from forced vibration test(FVT) and FE analysis. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.494-500
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• 2007

The comfort and quietness of vehicle has been improved greatly due to the development of technology in automobile industry. It is driven by reduction on the level of vibration and noise in powertrain system. However, the hidden problems in automobile parts become noticeable since the vehicle has been better in overall performance. One of them is related to the fuel pump system. Therefore, this study is focused on investigating the characteristics of fuel pump and fuel tank first, and then comparing the data before and after installation of fuel pump system in a testing vehicle. Additionally, the measured data will be analyzed to identify the problems and find a solution to improve the level of noise and vibration in fuel pump system.