• Proceedings of the KSR Conference
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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.

• Journal of the Korean Society for Railway
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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.

• Proceedings of the KSR Conference
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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.

• Journal of the Korean Society for Railway
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• 제19권5호
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• pp.576-584
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• 2016

In this study, we measured the air tightness of a train using pressure variation in tunnels. To estimate the air tightness of a train is essential to comprehend the pressure variation of the cabin because air tightness is strongly related with ear discomfort. If we can determine the air tightness, we can predict the pressure variation of the cabin. Also, ear discomfort is a problem that can be caused in a high speed train, as well as in Korea's Great Train Express. In this study, we compared the various international standards for ear discomfort and estimated the air tightness of each vehicle based on experimental data obtained using the ITX, KTX and KTX-sancheon(honam) vehicles. The internal pressure variation of the trains is numerically calculated using the air tightness value. The results are good compared to the experimental results. Instead of flap type ventilation, in the future, continuous ventilation equipment will be needed for speed-up.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 한국암반공학회 2007년도 특별심포지엄 논문집
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• pp.19-36
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• 2007

When the trains runs at a high speed in the tunnel, passengers feel a pain in the ear that fast pressure fluctuation inside the tunnel being delivered with pressure fluctuation inside the passenger car. These phenomena are called "aural discomfort". Aural discomfort increase the passengers' uncomfort so that it is decreased a service level and serious case, it is able to damage the ear of the passenger. therefore aural discomfort must be considered the high-speed railroad tunnel cross-section design. To solve the problem of aural discomfort in a railway tunnel, some countries have standards on aural discomfort. It has been studied that different countries have different standards on aural discomfort. For that reason, the criteria of aural discomfort was reviewed through the standards of Kyungbu HSR line and different countries in this paper. And then Numerical Analysis of the Characteristics with tunnel cross-section change has been used for the selection of the optimum cross-section of Honam. The numerical analysis results were compared to field test results in order to verifying the reliability of the numerical analysis.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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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.

• Proceedings of the KSR Conference
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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.

• Proceedings of the KSME Conference
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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.