• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.3
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• pp.213-220
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• 2008

In this paper, the regenerative inverter system with voltage drop compensation mode is proposed. When the main rectifier is broken, the DC traction can not be supplied the power from the utility. Actually, the reserve rectifier is mounted in the substation to prevent this accident. In this paper, the voltage drop compensation mode is added to the regenerative inverter system in order to substitute the reserve rectifier. The proposed regenerative inverter system returns the regenerative energy from the DC line voltage to the utility. In addition, the inverter can be compensate the harmonics caused by the power conversion devices used in the DC traction system. We demonstrated the effectiveness of the proposed control algorithm by using computer simulation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.71-73
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• 2014

본 논문에서는 지하철 내의 인구밀집도 파악을 통한 승객의 이용 편의성을 극대화하고, 군중밀도가 높은 지하철 구간의 경우 고른 인구분포 측정을 통한 승객의 편의성을 극대화하는 플랫폼 및 모바일 앱을 제안한다. 제안하는 시스템으로 기존의 지하철 역내에 설치된 CCTV에 모션벡터 영상처리와 RFID 기술을 결합한 Hybrid CDE로 구성되며, Size-Filtering을 통해서 재검출 과정을 거친다. 이러한 결과 값은 전동차 각 구간의 인구밀집도 정보를 정확히 측정 할 수 있다. 또한 결과 값을 바탕으로 효율적인 인구 유동을 유도할 수 있으며 정보 소외 계층 및 사회적 약자 등, 승객을 안전하게 보호할 수 있는 환경을 조성한다. 시스템 관리자는 학습기능 알고리즘을 통해서 오차 범위를 최소화한 플랫폼 설계를 통해 실시간 모니터링 함으로써 정보 습득 및 제공면에서도 새로운 시스템 설계 제안이 될 것이다.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.54-61
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• 2015

The ATVM(Automatic Ticket Vending Machine) of Seoul Metropolitan is a Kiosk which is called Ticket Vending and Reload Device at the subway station. It is implemented for integrating transportation card system which is separated from a paper subway ticket and replacing ticket selling employees. However, since the automatic ticket vending machine was accepted in 2009, there has been confusion of purchasing a ticket. Therefore, it requires improvement of usability. This study, conducts a literature search. Also, the interface of ATVM is analyzed. Finally user observation proceeded at Sinnonhyeon Station of Seoul Metro line 9. The results show that selecting a destination and section fares is confusing process for user. Based on this survey the improvements of UI are proposed to expect advanced directions of the ATVM.

• Advanced Industrial SCIence
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• v.2 no.4
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• pp.11-16
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• 2023

The subway is a means of public transportation that plays an important role in the transportation system of modern cities. However, congestion often occurs due to sudden breakdowns and system outages, causing inconvenience. Therefore, in this paper, we conducted a study on failure prediction and prevention using machine learning to efficiently operate the subway system. Using UC Irvine's MetroPT-3 dataset, we built a subway breakdown prediction model using logistic regression. The model predicted the non-failure state with a high accuracy of 0.991. However, precision and recall are relatively low, suggesting the possibility of error in failure prediction. The ROC_AUC value is 0.901, indicating that the model can classify better than random guessing. The constructed model is useful for stable operation of the subway system, but additional research is needed to improve performance. Therefore, in the future, if there is a lot of learning data and the data is well purified, failure can be prevented by pre-inspection through prediction.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.294-301
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• 2013

The particle matter concentrations in the subway stations should be monitored and controlled for the health of commuters on the subway system. Seoul Metro and Seoul Metropolitan Rapid Transit Corporation are measuring several air pollutants regularly. In this paper, the reliability of the cheap instruments using light scattering method is improved with the help of a linear regression analysis technique to measure the $PM_{10}$ concentrations continuously in the subway stations. In addition, a monitoring system is implemented to display and record the data of $PM_{10}$, $CO_2$, humidity, and temperature. To transmit and receive these measured sensor data, CDMA M2M wireless communication method is applied.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.1-7
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• 2010

Since subway fire disaster at Daegu, Korea smoke control system and passengers evacuation distance has been focused to reform. Existing smoke control facilities need to expand volume of ventilation capacity however, the complicate subway station structure can hardly react dispersion of smokes from massive subway cabin fire. Smoke flow at platform level move upward thought vertical stairway and passengers evacuation goes with same direction. The victims of evacuees from subway station fire mainly due to exposure of heat radiation and smoke. The study demonstration the effect of downward evacuates stairway system by separating evacuation route to smoke movement pass way including saving times of evacuation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.49-63
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• 2019

Crowdedness management at subway platforms is essential to improve services, including the prevention of train delays and ensuring passenger safety. Establishing effective crowdedness mitigation measures for platforms requires accurate estimation of the congestion level. There are temporal and spatial constraints since crowdedness on subway platforms is assessed at certain locations every 1-2 years by hand counting. However, smart cards generate real-time big data 24 hours a day and could be used in estimating congestion. This study proposes a model based on data from transit cards to estimate crowdedness dynamically. Crowdedness was defined as demand, which can be translated into passengers dynamically moving along a subway network. The trajectory of an individual passenger can be identified through this model. Passenger flow that concentrates or disperses at a platform is also calculated every minute. Lastly, the platform congestion level is estimated based on effective waiting areas for each platform structure.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.1-5
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• 2011

High concentration of carbon dioxide at subway cabin is one of the serious environmental concerns because carbon dioxide causes drowsiness, headache, and nervelessness of passengers. Ministry of Environment set a guideline for indoor carbon dioxide levels in train or subway in 2007. In this study, a carbon dioxide removal system for subway cabin was developed and tested using a test subway cabin. Various types of modified zeolites were used as the adsorbent of carbon dioxide. The tested zeolites were applied to the subway cabin, and showed high potential to lower the indoor $CO_2$ level.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.532-533
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• 2008

본 논문에서는 하루에 수백만 명이 이용하는 지하철 역사내의 환경 관리를 유비쿼터스(Ubiquitous) 기술을 적용하여 실질적이고 효과적으로 실행하는 방안을 제안하고자 한다. 지하철 역사는 지하라는 특수한 환경이기 때문에 외부의 신선한 공기를 유입하여 역사내의 공기질을 쾌적하게 유지해야할 필요가 있다. 또한 실내 공기질을 오염시키는 환경가스나 미세먼지 등의 오염도에 대해서도 지속적으로 감시하여야 한다. 이를 위해 설치가 간편하고 소형의 측정 장치를 지하역사내의 주요 지점에 설치하여 오염물질을 측정하고 그 결과 데이터를 모으는 집중기(Collector)를 운영하여 최종적으로 측정 데이터를 중앙 서버까지 전송할 수 있다면 지하철 관리자에 의한 지하역사내의 오염물질을 효과적으로 관리 감독하는 종합적인 지하철 환경 관리시스템의 운영이 가능할 것으로 판단된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1278-1281
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• 2021

본 논문에서는 시각장애인들의 지하철 이용의 불편함을 최소화할 수 있는 내비게이션 앱을 개발하였다. 스마트폰 카메라가 전방을 인식하여 사물을 판단 후 장애물 혹은 위험요소를 사용자에게 음성으로 전달한다. 또한, 사용자의 원활한 지하철 이용을 위해 공공데이터를 활용하여 지하철 환승 정보, 화장실, 출구 정보 등의 이동 편의를 위한 실질적인 정보를 제공한다. 시각장애인은 본 앱을 활용하여 지하철을 더욱 편하고 안전하게 이용할 수 있다.