• Proceedings of the KSME Conference
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• 2001.11a
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• pp.629-634
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• 2001

The construction of the elevated railway has led to concerns about the noise from trains, particularly as tracks often pass close to residential dwellings. One specific issue relates to the noise from trains on bridges. The wayside noise for the train was measured to get the basic data that can be used to prepare count measures for solving environmental noise problems. Noise levels were measured simultaneously at three points in various distances from the railroad and at four points classified by floor. In this paper we measure the wayside noise in elevated railway and noise of normal operation compare with operating under train engine idling condition and investigate effect of nearby-building induced by train operation.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.170-175
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• 2005

In this study, experimental and theoretical methods were applied to understand brake squeal noise VVVF rolling stock on tracks. Trailer cars needed to payed a particular attention, because they were the major source of brake noise. VVVF rolling stocks for lines no 1 of the subway system in Seoul were used for experimental analyses. In order to study brake squeal noise, a dynamometer test at the S&T Brake, Co., which was a manufacturer of brake pads had performed. For measuring vibration and noise, vibration tests of brake parts (brake lining, brake lining head, back plates, etc.) at the SNUT were executed. Also, vibration tests of disc assembly and lining block at the heavy maintenance shop of the Gunja depot were performed. The modal analyses by using an ANSYS which was one of the CAE commercial program were simulated to know the relationship to the mechanism of brake noise. On the based of the tests and the simulations it was found that specific frequencies of the brake parts affected squeal noise, and improvements for reducing squeal noise were proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.25-32
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• 2005

In China, environmental noise policies are composed of correlated laws adopted by the Standing Committee of the National People's Congress and promulgated by the President of the country, regulations promulgated by the State Council and/or local government, standards issued by the Standardization Administration Committee (SAC) under the State Council. The laws mainly include the 'Environmental Protection Law' and the 'Law on Prevention and Control of Pollution From Environmental Noise' Regulations are often applied to a special noise pollution phenomenon of wide influence. They are generally only effective in a given area and/or a specific period. Tens of correlated standards specify the noise level limits of different functional zones of land use and of different equipment, machines, devices, appliances etc., and the measurement methods. In this presentation, a brief introduction to these policies and their operations is given and discussed. The conclusion is that the policies supply an effective legislative basis for environmental noise prevention and control in China, but still a lot of work should be conducted and completed to strive for a quiet society.

• Journal of KSNVE
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• v.7 no.3
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• pp.521-529
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• 1997

Noise pollution, especially road traffic noise-in terms of population exposure-has become a major problem in Seoul. However, although noise can be sensed directly, it is considered somewhat less important compared to other environmental pollutions. In this study, we chose nine districts in Seoul and distributed a questionnaire containing 23 questions in related to the awareness of noise pollution for 950 people living in Seoul. The results were analyzed according to the citizens' awareness on the whole, age, occupation, and were compared to the actual noise level measured by the Seoul Metropolitan Government. The analysis of the questionnarie show that road traffic noise is considered to be the main source of noise pollution in Seoul. People think that the individual and the Seoul Metropolitan Government are most responsible for the noise reduction in Seoul, but replies only little effort is put into when asked whether one has made any personal effort to reduce noise. We have concluded that noise pollution is not considered a hazardous problem to most Seoul citizens, and that most of them seem to be used to it. Yet, specific noise reduction policies, especially road traffic noise, are expected to take effect as quality of life is pursued due to economic enhancement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.394-401
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• 1996

Noise pollution, especially road traffic noise has become a major problem in Seoul. However, although noise can be sensed directly, it is considered somewhat less important compared to other environmental pollutions. In this study, we chose nine districts in Seoul and distributed a questionnaire composed of 23 questions in related to the awareness of noise pollution for 950 people living in Seoul. The results were analyzed according to district area, age, occupation, and were compared to the actual noise level measured by the Seoul Metropolitan Government. The analysis of the questionnaire show that road traffic noise is considered to be the main source of noise pollution in Seoul. People think that the individual and the Seoul Metropolitan Government are most responsible for the noise reduction in Seoul, but replies only little effort is put into when asked whether one has made any personal effort to reduce noise. We have concluded that noise pollution is not considered a hazardous problem to most Seoul citizens, and that most of them seem to be used to it. Yet, specific noise reduction policies, especially road traffic noise, are expected to take effect as quality of life is pursued due to economic enhancement.

• Journal of Environmental Science International
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• v.6 no.6
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• pp.551-562
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• 1997

Nine districts in Seoul were chosen randomly and a questionnaire containing 23 questions was distributed to survey the perception of noise pollution by the citizens. The results were primarily analyzed to understand the perception of Seoul citizen as a whole, and then analyzed according to 4 demographic variables -district area, age, gender and occupation -to see if there were any possible relation between nonnoise variables and noise annoyance. Actual noise level data measured by the city government were used to compare quantified noise level with the surveyed people's perception. It was found that people consider road traffic noise to be the naix source of noise pollution In Seoul and that most people have experienced annoyance in everyday life. Also it was verified that the responsibility for noise control should be on both city government and the individuals, but It was generally considered that very little effort Is actually put Into solong norse pollution from both groups. From the survey, It could be analyzed that domographic variables do affect people In the awareness of noise pollution, and that one's sensitifty and annoyance due to noise increase as one ages. From the study, It was concluded that noise pollution Is not considered currently as a hazardous problem to most Seoul citizens, however specific noise reduction policies, especially regarding road traffic noise, should be put Into practice In the near future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1024-1028
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• 2006

The Fe-Mn damping Alloys which combine a high damping capacity with good mechanical properties can provide attractive technical and economic solutions to problems involving fatigue, noise and vibration. This study is aimed at finding its applicability to divided spherical bearing in bridge. The results obtained are summarized as follows : 1) The specific damping capacity of the Fe-Mn damping alloy is superior to that of SM490B. 2) The divided spherical bearing manufactured Fe-Mn damping alloy passes the load test to confirm applicability of that in bridge.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.651-662
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• 1995

In Korea there is no specific method of age adjustment in noise induced hearing loss(NIHL). We attempted the age adjustment to understand the effects of age on the diagnosis of NIHL. We used the International Standard Organization 1999 as an age adjustment method. We used the 1, 617 otologically normal person's hearing data from a health examination center, and 206 workers diagnosed as NIHL. We concluded as follows; 1. The ISO 7029 function used for age specific hearing loss is not suited to Korean people. 2. The mean of age specific hearing loss is 11.0 6.2dB and the older of age, the more decrease on hearing loss, especially in 4000Hz. 3. The difference of NIHL between before age adjustment and after age adjustment in the 3rd decade is 5.4dB, in the 4th decade is 6.7dB, in the 5th decade is 8.5dB, in the 6th decade is 10.4dB, and in the 7th decade is 12.9dB. The older, the more is the difference. 4. After age adjustment, the number of workers diagnosed as NIHL decreases to 60% of unadjusted.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1103-1107
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• 1990

This paper describes a new method of noise-canceling in an instrumentation using a pair of identical Potential Transformers (PT). This method allows us to get reliable signals without any noise, not only on the transmission line, but also on the sensors; even if we do not have a reference noise or a specific noise. In this case "any noise" means normal mode noise (NMN), under a quarter frequency of the switching. We proposed to call this method alternating noise-canceling (ANC). The accuracy of this new method has been verified by experimentations.entations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.402-405
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• 2006

The diffuser noise of HVAC(heating ventilating and air-conditioning) uses dB(A) or NC as a indoor noise criteria that ASHRAE represents, and there is no specific guide line for application. According to the previous study, there are some problems like that even though the sound level of sound source is same, the NC shows different values, which makes the noise rating confused. This problem is caused by the frequency characteristics of sound source and its sound level. Therefore, appropriate evaluation method should be considered based on the subjective responses. This study aims to analyze the physical parameters appropriate for the evaluation of HVAC diffuser noise. To achieve this, recording of sound sources, calculation of physical parameters and psycho-acoustic experiment were carried out and the results were derived from the correlation analysis between physical parameters and subjective evaluatio