• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.281-286
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• 2003

Experimental study is conducted to clarify the inside and outside pressure variation of passenger cabin for KTX. These pressure variation may give rise to the ear-discomfort. Generally ear-discomfort has been considered as a problem related to high speed train. In this study, the pressure variation of interior, gangway and exterior of KTX passenger car is measured by using the atmospheric pressure sensors and portable data acquisition system. The tunnel from 4000m to 200m in length are chosen for the investigation of length effects. From the results of experiment, the pressure variation of interior per second is under the ear-discomfort limitation in all of tunnel. And, We found that there is a similar pattern of exterior pressure variation. These results generally agree with RTRI's experimental result for Shinkansen.

• 한국철도학회논문집
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• 제7권1호
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• pp.26-31
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• 2004

A study is conducted to clarify internal and external pressure variation of passenger cabin for KTX. These pressure variation may give rise to the ear-discomfort for passenger and fatigue for carbody. In this study, the pressure variation of interior, gangway and exterior of KTX passenger car is measured by using the atmospheric pressure sensors and portable data acquisition system. The tunnel from 4000m to 200m in length are chosen far the investigation of tunnel length effects. From the results of experiment, the pressure variation of interior per second is under the ear-discomfort limitation in all of tunnel. And, We found that there are similar patterns of exterior pressure variation for each critical tunnel length. These results generally agree to RTRI's experimental result fur Shinkansen.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.495-502
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• 2000

For the tunnel design of the first class on new Seoul-Chunchon railway, we investigated for train speeds to run through tunnels without ear-discomfort of passenger in cabin by application of numerical analysis. Also we analyzed the effect of the wind speed induced by train in tunnel that is very harmful to the workers on railroad and the effect of the air-pressure fluctuations which get the fatigue to the tunnel lining and the car body.

• 한국철도학회논문집
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• 제19권5호
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• pp.576-584
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• 2016

본 연구에서는 터널에서의 압력 변동값을 이용하여 차량의 기밀도를 측정하였다. 차량의 기밀도는 이명감과 깊은 관계가 있으므로, 차량의 기밀도를 추정하는 것은 실내 압력 변동을 파악하는데에 필수적이다. 차량의 기밀도를 알면, 실내압력 변동을 예측할 수 있다. 또한 이명감은 고속열차 뿐만아니라 급행 대심도 열차에서도 야기될 수 있는 문제이다. 본 연구에서는 각국의 다양한 이명감 기준을 비교 검토하였으며, ITX-청춘, KTX, KTX-산천(호남) 차량을 이용한 현차실험 데이터를 바탕으로 각 차량의 차량 기밀도를 추정하였다. 이 기밀도 값을 이용하여 차량 내부의 압력 변동값을 수치계산하였으며, 시험값과 비교하여 양호한 결과를 얻었다. 향후 고속차량 고속화를 위해서는 환기장치를 차단식이 아닌 연속환기 방식으로 할 필요가 있다.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2007년도 특별심포지엄 논문집
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• pp.19-36
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• 2007

열차가 고속으로 터널을 주행하는 경우, 터널내부의 압력변동은 곧 차량내부의 압력변동으로 전달되어 승객의 귀를 아프게 하는 경우가 있다. 이러한 현상을 이명감이라 하며, 이명감은 승객의 불쾌감을 증가시켜 서비스 수준을 저하시키고, 심할 경우 승객의 귀를 손상시킬수 있으므로 고속철도 터널설계시 반드시 고려해야 한다. 이에, 국내 및 해외 고속철도의 경우, 이명감 기준을 수립하여 적용하고 있으나, 개인의 주관적 차이 및 승객에 대한 서비스 수준의 차이 등에 따라 서로 상이한 기준이 적용되고 있다. 따라서, 본 논문에서는 국내 외 이명감 기준을 조사 분석하였으며, 이를 토대로 수치 시뮬레이션을 수행하여 호남고속철도의 터널단면을 검토하였다. 또한, 경부고속철도를 운행하는 열차의 터널통과시 압력변동량을 측정하여, 수치시뮬레이션 입력조건으로 사용된 각종 매개변수 등의 적정성을 비교 검증하였다.

• Safety and Health at Work
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• 제12권2호
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• pp.184-191
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• 2021

Background: Hearing protection devices (HPDs) are often used in the workplace to prevent hearing damage caused by noise. However, a factor that can lead to hearing loss in the workplace is improper HPD fitting, and the previous literature has shown that instructing workers on how to properly insert their HPDs can make a significant difference in the degree of attenuation. Methods: Two studies were completed on a total of 33 Hydro One workers. A FitCheck Solo field attenuation estimation system was used to measure the personal attenuation rating (PAR) before and after providing one-on-one fitting instructions. In addition, external ear canal diameters were measured, and a questionnaire with items related to frequency of use, confidence, and discomfort was administered. Results: Training led to an improvement in HPD attenuation, particularly for participants with poorer PARs before training. The questionnaire results indicated that much HPD discomfort is caused by heat, humidity, and communication difficulties. External ear canal asymmetry did not appear to significantly influence the measured PAR. Conclusion: In accordance with the previous literature, our studies suggest that one-on-one instruction is an effective training method for HPD use. Addressing discomfort issues from heat, humidity, and communication issues could help to improve the use of HPDs in the workplace. Further research into the effects of canal asymmetry on the PAR is needed.

• Archives of Plastic Surgery
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• 제43권6호
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• pp.512-517
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• 2016

Background Studies of the ear-molding technique have emphasized the importance of initiating molding early to achieve the best results. In the present study, we describe the immediate effects and long-term outcomes of this technique, focusing on children who were older than the ideal age of treatment initiation. Methods Patients who visited our institution from July 2014 to November 2015 were included. Medical charts were reviewed to collect data on demographics, the duration of treatment, the types of deformities, and the manner of recognition of the deformity and referral to our institution. Parents were surveyed to assess the degree of improvement, the level of procedural discomfort at the end of treatment, any changes in the shape of the molded auricle, and overall satisfaction 12 months after their last follow-up visits. Results A review of 28 ears in 18 patients was conducted, including the following types of deformities: constricted ear (64.2%), Stahl ear (21.4%), prominent ear (7.1%), and cryptotia (7.1%). The average score for the degree of improvement, rated on a 5-point scale (1, very poor; 5, excellent), was 3.5 at the end of treatment, with a score of 2.6 for procedural discomfort (1, very mild; 5, very severe). After 12 months, the shapes of all ears were well maintained. The average overall satisfaction score was 3.6 (1, very dissatisfied; 5, very satisfied). Conclusions We had reasonable outcomes in older patients. After 1 year of follow-up, these outcomes were well maintained. Patients past the ideal age at presentation can still be candidates for the molding technique.

• 대한기계학회논문집B
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• 제28권9호
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• pp.1042-1050
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• 2004

Theoretical study has been conducted to clarify pressure characteristics of KTX(Korea Train eXpress) in tunnel. The severe pressure change in tunnel may give rise to the ear-discomfort for passenger and fatigue for car body. The external and internal pressure of rolling stock have been measured by using the running test with atmospheric pressure sensors and portable data acquisition system in high speed train. In this study, the tunnels from 200m to 4000m in length have been chosen for the investigation of tunnel length effects. We found that there are similar patterns of external pressure change for each critical tunnel length. The critical tunnel lengths are governed by train speed, train length and sonic velocity. And, the patterns of pressure wave in tunnel are classified into eight groups.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.521-526
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• 2000

Experimental study is conducted to clarify pressure variation of the passenger cabin of conventional train. These pressure variation may give rise to the ear-discomfort. Generally ear-discomfort has been considered as a problem related to high speed train. Because there is also a good progress to speed-up for conventional line, this isn't only a phenomena related to high speed train any longer. In this study, tile pressure variation of interior, gangway and exterior of saemaeul passenger car is measured using the atmospheric pressure sensors in Honam line. From the results of experiment, the pressure variation per second almost close in upon the limitation in the case of Noryong tunnel. Therefore, to accomplish speed-up for conventional train, it may be necessary to study a serial ventilating and the airtightness of carbody.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1655-1660
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• 2004

Theoretical study has been conducted to clarify pressure characteristics of KTX(Korea Train eXpress) in tunnel. The external and internal pressure of rolling stock have been measured by using the atmospheric pressure sensors and portable data acquisition system on Seoul-Busan high speed railroad line. These pressure change may give rise to the ear-discomfort for passenger and fatigue for car body. In this study, the tunnels from 200m to 4000m in length have been chosen for the investigation of tunnel length effects. From the results of experiment, the pattern of pressure change generally agrees to RTRI's experimental result for Shinkansen. We found that there are similar patterns of external pressure variation for each critical tunnel length. The critical tunnel lengths are governed by train speed, train length and sonic velocity.