• 대한의생명과학회지
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• 제13권3호
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• pp.231-237
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• 2007

Subway environments such as crowd, passenger's gab, or subway-generated mechanical noise may become a potential stressor. The present study was sought to determine whether subway noise with or without mental activity affects cerebral hemodynamics and sympathetic system. Fifty-four healthy volunteers were divided group I which underwent subway noise (n=24) and group II which underwent a combined mental activity (mental arithmetic) with subway noise (n=30). Sympathetic factors such as heart rate (HR), blood pressure (BP) and heart rate-systolic pressure product (RPP), and mean blood flow velocity in the middle cerebral artery (MCAV) were measured before (baseline), during and after the noise-exposure. Systolic and diastolic blood pressure, HR and RPP significantly increased in group II (P<0.05) but not in group I during the noise-exposure. Peak-MCAV, diastolic-MCAV and mean-MCAV in the both groups were elevated during the noise-exposure (P<0.05) and the increased ratios in group II were greater than those in group I. These results suggest that a combined mental activity with subway noise may be a stressor which affects cerebral hemodynamics and sympathetic system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.934-937
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• 2004

The purpose of this study is to present a fundamental data to get the noise reduction method of subway station in Gwang-ju city. Subway noise level measurement and questionnaire on the satisfaction of sound condition were carried out. The results show that the noise level of the subway station and the noise reduction effect installed by screen door is over 10 dB(A).

• 한국철도학회논문집
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• 제10권5호
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• pp.480-486
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• 2007

대도시에서 지하철은 많은 도시민들에게 필요한 대중교통수단이다. 그러나 이용수요가 증가함에 따라 환경에 관련된 많은 문제가 발생하였다. 본 연구는 최근 사회적 관심사가 되어 있는 지하철 차내소음 문제를 연구대상으로 선정하였다. 지하철 5호선의 기하구조 및 운영요인을 수집하고, CART분석을 통해 소음자료 특성을 반영한 소음 영향모형을 개발하였다. 모형개발결과 지하철 기하구조 및 운영적 측면의 유형별로 소음에 미치는 영향들에 차이가 있는 것으로 나타났다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.887-890
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• 2007

The low frequency noise, including infra-sound is known to affect human physiology and psychology. Guidelines and measurement method of low frequency noise has been introduced in several countries in order to evaluate low frequency noise. In this work, low frequency characteristics of Daejeon subway was investigated in terms of the noise level and spectrum in the interior of running subway car and the subway station. The interior sound pressure level of the passenger car was between 60 and 102 dB in the frequency range of $1{\sim}250$ Hz.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.487-494
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• 1999

The object of this study is to reduce the subway noise by the low noise wheel. The vibro-acoustic reduction was predicted from the FRF difference between low noise wheel and solid wheel by experimental modal analysis. The low noise wheel and solid wheel were compared in viewpoint of car interior/exterior noise. The effect of low noise wheel on the noise of subway train of 6 vehicles was obtained. But, the application of low noise wheel must be reviewed in some aspect.

• 기술사
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• 제19권2호
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• pp.21-25
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• 1986

Structure-borne noise due to forced vibration which is originated from subway operation and transmitted to buildings in order of rail-wood tie-concrete bed-structure-soil-building foundations-members of building results in social problem of environmental pollution. Moreover this becomes a serious problem because of the increment of surface traffic and subway operation made by meeting traffic system in crowded cities. Since subway is constructed along the principal road or through the residential area and as the worst case may be, building foundations is contact with top part of subway structure, it is possible that vibration resonance results in fatal damage of buildings. And, structure-borne vibration noise due to subway operation at late and early hours have the residents suffer from insonmia, restlessness and so on. Therefore, to satisfy the future need concerning the environmental protection, this report deals with the influence of structure-borne vibration noise on the basis of the characteristics of Seoul Subway System.

• 한국소음진동공학회논문집
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• 제19권1호
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• pp.85-93
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• 2009

There are many curves in Seoul subway system. Therefore, the noise from subway system in curved line gives displeasure to passenger. The subway noise in curved line is affected not only by rail condition but also wheel condition and dynamic characteristics. The railway curving noise can be divided into 2 categories. The first is the noise due to stick-slip between wheel tread and rail head, and the second is one by wheel flange contact on rail side. Because of these phenomena - stick-slip and wheel flange contact - wheels are worn seriously. In this study the curving noise was reviewed by using eigen-mode of wheel and waterfall plot which shows noise level in time-frequency domain. And also those were reviewed in viewpoint of stick-slip noise and wheel flange contact noise. Finally, the relationship between curving noise and wheel wear was studied.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.536-541
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• 2003

When a rail vehicle transverses tight curves, it often emits an intense, high-pitched squeal. This squeal has always been noticed as one of the most disturbing noise sources of railway systems. At present, w cannot predicted squeal noise that is influenced by a large number of dependent parameters. In this study, we performed structural analysis to find out the frequency of the wheel and measured squeal noise at Seoul subway. We also tested reduction effectiveness of squeal noise through rail lubricator

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.340-345
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• 2002

Passengers in automobile or train are exposed to a worse noise environment when they are in the tunnel than in the open field. This is due to a relatively higher space density of sound energy by multiple reflection phenomenon of noise generated by operation of transportation vehicles from tunnel wall compared to open field. In this study, noise characteristics of subway train running through a tunnel were investigated at straight/curved track and tunnel type(semi circular/box). Also the noise measured simultaneously at inner and outer sides of train running through a tunnel, so that the coherence of the various noise sources of subway train to inner noise was evaluated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.670-677
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• 2009

The purpose of this study is to reveal the quantitative dose-response relationship between the noise emitted in the platform of subway station and the public response. The noise measured in the platform of subway station was used for a jury test. In order to find the factors which influence annoyance response due to the platform noise, jurors were examined for the difference of the annoying response, interrelation of sound quality parameter and annoyance response. The platform noise level was 77.2$\sim$83.9 dBA and the most of passengers at the platform were highly annoyed. And screen door contributes to annoyance reduction of platform noise. The results from analyzing sound quality parameters shows that loudness and annoyance response have a high correlation coefficient.