• 한국환경보건학회지
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• 제28권5호
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• pp.71-76
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• 2002

A survey of radon concentrations in both indoor and outdoor atmospheres was carried out using EIRM and Cup Monitor for the period of February 1996 to March 1997. EIRM were used to measure the indoor and outdoor radon concentration at five major cities university. Cup Monitor were also used to measure the indoor radon concentrations at shopping store, office building, apartment, hospital and house in Seoul. The mean indoor and outdoor radon concentrations at the five major cities(Seoul, Daegu, Daejon, Cwangiu and Busan) were 24.1 Bq/m$^3$and 8.62 Bq/m$^3$, respectively. The ratio of indoor to outdoor radon concentrations ranged front 1.7 to 3.9. Inspection of its seasonal distribute pattern indicates the enhancement during winter relative to summer, consistently for both indoor and outdoor air. The results of the survey showed that the concentrations in basements were clearly higher than those in usual living/working places.

• Journal of Mechanical Science and Technology
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• 제18권1호
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• pp.37-44
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• 2004

This paper presents an approach to optimally design the air bearing surface (ABS) of the head slider by using the approximation methods. The reduced basis concept is used to reduce the number of design variables. In the numerical calculation, the progressive quadratic response surface modeling (PQRSM) is used to handle the non-smooth and discontinuous cost function. A multi-criteria optimization problem is formulated to enhance the flying performances over the entire recording band during the steady state and track seek operations. The optimal solutions of the sliders, whose target flying heights are 12 nm and 9 nm, are automatically obtained. The flying heights during the steady state operation become closer to the target values and the flying height variations during the track seek operation are smaller than those for the initial one. The pitch and roll angles are also kept within suitable ranges over the recording band.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.857-862
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• 2002

철도차량의 주행장치는 비틀림 선로를 주행할 경우 윤중감소가 발생하게 되며 이 값은 모든 하중 조건 및 공기스프링의 충기/배기 상태에서 UIC/ORE 보고서에서 규정한 기준치 60% 이내를 준수하여야만 한다. 이 논문은 인도 DMRC 전동차를 대상으로 시험을 실시하여 DMRC 선로 중 최악의 조건에서 UIC / ORE 에서 규정하고 있는 차량의 윤중감소율( Wheel Off-loading)의 기준을 만족하는 지에 대한 평가한 것을 기술하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.270-275
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• 2007

Pollutants emitted by Diesel trains seriously affected on the ventilation characteristics in the subway or railway tunnel network systems. Thus, numerical prediction results and analyses are required to engineers who should design ventilation facilities. So here, this paper presents some numerical results about the ventilation characteristics, such as pollutants distributions and a suitability of the ventilation facilities pre-designed in case that diesel trains use the same railway track with normal passenger trains

• 한국산학기술학회논문지
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• 제17권1호
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• pp.290-297
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• 2016

도시철도 터널내에 축적된 미세먼지(PM10 and PM2.5)의 제거를 위해 사용되는 분진흡입차량의 성능은 하부흡입시스템의 설계방법에 따라 성능이 달라진다. 본 논문에서는 터널집진차량의 하부에 설치된 먼지흡입시스템의 고효율화를 위하여 궤도의 바닥면에 쌓인 먼지를 비산시키는 압축공기 블로어와 먼지 흡입구를 동시에 가지는 모듈화된 먼지흡입구조를 제안하였다. 흡입과 블로어의 상반된 구조를 동시에 가진 흡입시스템의 먼지유동 최적화를 위해 난류유동에 기초한 수치해석을 수행하였다. 해석결과로 먼지흡입효율을 최대화 할 수 있는 공기 블로어의 설치각이 $6^{\circ}$ 내외에서 결정되고, 이를 적용하면 5 km/h의 청소속도를 가지는 분진흡입차량의 흡입효율을 10%이상 높일 수 있음을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.283-285
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• 2002

Boiler combustion systems are large, non-linear systems with numerous interactions between its component parts. In the analysis of such complex systems. dynamic simulation is recognized as a powerful method of keeping track of the myriad of interactions. This paper shows and discusses the developed analysis model, such as the forced draft fan the primary air fan, the furnace and burner system, pulverizer, air preheater and induced draft fan, etc. in accordance with BMCR condition of boiler using the Modular Modeling System(MMS) software.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.442-444
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• 2006

On long time scale and over large areas ground surface temperatures (GSTs) track surface air temperatures (SATs). Additionally, GST changes penetrate into the subsurface and are recorded as transient temperature perturbation to the background thermal filed. Therefore, climate change can be reconstructed from borehole temperature measurements We present GST hi story reconstructed from temperature measurements in a borehole at Pocheon The result shows that GST cold period in the late 19th century and then increased by about 2K to 1990. GST history matches well with surface air temperatures measured from 1907 to 2001 at the Seoul Meteorological Station and GST history reconstructed from temperature measurements in three boreholes at Ulsan.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.316-320
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• 2008

A light rail transit, using a linear induction motor, is generally composed with reaction plates along railroad track and the three phase primary on the vehicle. This linear induction motor is driven to keep clearance between the primary and the secondary of the ground for preventing any contact. Therefore efficiency and power factor is very low. In addition, the reaction plate installed on the ground throughout entire railway is impossible to keep uniform gap and it may cause system deterioration. In this paper, A rotary-type small-scale model of a linear induction motor for various characteristic analysis is designed. Thrust force, normal force and input current of the model by air-gap variation have been analyzed by using a Finite Element Method (FEM). The effects of air-gap variation on system performance have been considered by analysis results.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.136-141
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• 2009

The platform screen door(PSD) is installed in the station of the Seoul Metro 9th line for passengers' safety and comfortable environment of the station. The track way exhaust system(TES) is also operated with PSD to exhaust heat released from train. TES can also be used for the purpose of the heat and smoke control in an emergency case of the carriage fire. When the fire is occurred, operation of TES is switched to the smoke exhaust mode form its normal ventilation mode. In the present study, a subway station of Seoul Metro 9th line is modeled, and a 3-D CFD simulation is performed to investigate effectiveness of designed TES in case of fire. A scenario that a train under fire is arriving the station is simulated for several possible operation modes of the TES using moving mesh technique. As a result, temperature and CO concentration distribution in the station is obtained for each operation modes of TES. The effectiveness of TES operation in case of fire is also discussed.

• 전기학회논문지
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• 제65권8호
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• pp.1466-1477
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• 2016

This paper analyzes the electrical characteristic such as the impedance(Z), inductance(L), and cable resistance($R_p$) according to the change of cable length in order to move the electrical sorting device for distinguishing between AF non-insulated track circuits from the center of railway to outside railway. The simulation is performed to check the voltage difference between the voltage of sender and the voltage of receiver and determine the possibility of the voltage restoration availability in the frequency filter band through the capacitor compensation. It was applied to the results of the simulation to the sorting devices installed in the actual field. It is proved the availability by checking the measured voltage characteristic according to the capacitor compensating change of $10{\mu}F$ and $16{\mu}F$ before, and after the length of cable is increased with 6 meters. Through this, the prevention of breakdown and damage to facilities and the prevention the safety-related accidents of line workers from the train are expected according to moving the sorting devices of AR non-insulated track circuits to outside railway.