• 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.

• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.247-251
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• 2006

The traction DC feeder cable is one of the key devices for the safety operation of subway system, but for low voltage DC feeder cable (<3000 V) for subway, little attention has been paid by investigators on its online monitoring technology. With an introduction of cable laying and operation environment for the cable, this paper investigated the on-line monitoring technology of 1500 V DC feeder cable of subway. Firstly, in the text, the fault model of 1500 V DC cable was proposed based on the analysis of the fault type of the DC feeder cable, and then put forward synthetically on-line monitoring discharge signal and DC leakage current signal to assess DC feeder cable insulating state. The results of laboratory experiment prove that the proposed methods are feasible and can be implemented on-line monitor on DC feeder cable of subway.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.940-956
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• 2004

In the course of studying the design of securing the 100-year-long durability of 100 years the subway structure according to the requested service by the Seoul Metropolitan Subway Construction Headquarters, we analyzed 14 construction sites adopting the durability design in subway line No. 9 and concluded as follows: 1. When comparing with 158, the environment index presented for securing 100-year-long durability of subway structure in subway line No. 9, the index of durability was verified as 159.7$\~$179.8 2. When examining the increase value of durability index, we verified that the constructors didn't make various choices in method but they employed the uniformly selected system. 3. Under consideration of the bid form, the construction under bid contract in bulk gave the impacts on the construction cost with attention to selection of the durability index, while the construction under alternative contract in bid adopted uniformly the standard presented by the ordering party.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1332-1334
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• 2003

Safety of breaking facility is very important in subway safety, especially in case of subway that many people used, breaking capability is connected directly with safety and capability of vehicle. Recently, direction of subway technical development is established as passenger's convenience and agreeableness. However, we are known importance of safety in subway through Dae-gu subway incendiary case. Subway accident not happen only fire, vehicle collisions or passenger's fall to the track can happen. In this case, safety standard of breaking facilities is very important. so this paper define safety of breaking facilities and take proper that standard.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.168-173
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• 2004

This research shows the method about the auto extinguishing system construction for the subway train's safety operation. The safety system is the total auto extinguishing system which it is able to overcome the emergency situation, to see fast using the sensing system, to interface using the communication system, finally to extinguish the large-scale fire happened. The system model is the total disaster mitigation system model preventing the arson or terror. and to apply a method of the fire extinguishing system using reinforced fire extinguishing agency in the world first. It is to use the subway train and the railroad train which is prevented and mitigated the large-scale demage the same as the arson and the terror.

• 한국대기환경학회지
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• 제30권2호
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• pp.175-187
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• 2014

The subways play an important part in serious traffic problems. Almost seven million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan city in 2012. However, the subway system is a semi-closed environment, so many serious problems occurred in subway stations and injured passengers' health. Platform screen doors (PSD) are expected to prevent negligent accident such as injury or death from falling and improve the air quality of the subway station. Installation of PSD at stations in Seoul metropolitan subway had been completed in December 2009. Consequently, the underground transportation system became a closed environment, so the air quality has improved the platforms, but it has deteriorated in the tunnels. Especially, the subway cabin has many doors, and the doors are frequently opened and closed. For this reason, the effect of door opening on subway cabin, dust flow inside the subway cabin. In this process, the maintenance work may influence the health of people who work underground, as well as that of subway users (passengers). In this study, we measured air quality inside and outside of the subway cabin line 2 in Seoul, Korea. This study focused on the investigation of Indoor Air Quality (IAQ) and measurement target pollutants are PM10, CO, $CO_2$, $NO_2$, $O_3$. It was found that levels of PM10, $CO_2$, and $NO_2$ inside subway cabin line 2 exceeded the Korea IAQ standard. Concentrations of PM10, $CO_2$, and $NO_2$ inside of the cabin are higher than outside of the cabin (Indoor Outdoor ratio is higher than 1.). Concentrations of CO, $O_3$ inside of the cabin are lower than outside of the cabin (Indoor Outdoor ratio is lower than 1.). There is a high correlation between $CO_2$ and passengers inside of the cabin and PM10 is only the weakest correlation with passengers. Therefore, it is important to find out the emission source of $NO_2$. The results of this study will be useful as fundamental data to study indoor air quality of a subway cabin.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1641-1646
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• 2007

Subway station is installed with equipment of deficient ventilation and air purification in need of routine activity for users because projectors didn't have recognition of the importance of prevention equipment on disasters in subway stations. So if the accident in Deagu is occurred again, we can't prevent it. And it is urgently necessary to improve antique subway station for the safety and service to citizens because users were increased far more. Improvement of subway station has to be modernized the backward and antique subway station and maintained and developed by the center of traffic to give the social contribution with management of social facilities. And subway station has to be made conveniently so that everyone may use the station with one-stop system including sales, business, service equipment. This study will show the improvement plan of problem in underground space and situation of metropolitan-train history to improve metropolitan-train station .we will study a traffic line and equipment relocation of underground space considering safety by choosing the improved station and problems of the underground station in seoul. And then we will study the improvement plan of air purification and sound isolation to upgrade service in citizens.

• Asian Journal of Atmospheric Environment
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• 제9권3호
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• pp.205-213
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• 2015

The objective of the current study was to assess the comparative risk associated with exposure to particulate matter (PM) while commuting via different public transport modes in Fukuoka, Japan. For the given routes and measuring days, a trip-maker carried a lightweight portable bag loaded the real-time measurement devices which take simultaneous measurement for size-fractioned particle number concentration, $PM_{2.5}$ mass concentration, and total suspended particle (TSP) collection. The results of the present study have shown significant differences between public transports as commuting modes in Fukuoka. The PM exposure levels on subway platform and inside subway train were overwhelmingly higher than those of other points on commuting route. The relative ratio between modes (i.e., the ratio of $PM_{2.5}$ inside subway to that inside bus) provides an idea for choosing a right commuting mode for our health. This study clearly provided evidence of the extremely high levels of iron exposure by subway uses compared to bus uses. The result of theoretically reconstructed mass concentration of $PM_{2.0-0.3}$ collected on subway platform suggests that the PM of underground subway will be associated with PM both generated in subway system and inleakaged from outdoor environment.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.470-480
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• 2008

After 1th line was built in 1974, the history of subway in Korea has been expended to 9th line which is under construction. It is time to prepare nation wide subway grounding system urgently according to the domestic electric standard that aligns to world wide standard by WTO/TBT treat (1995). Newly added grounding system to the fundamentally different system caused many problems. PSD(platform screen door) and other newly added equipment are also need grounding system. By the electrical code(established by Korea Electric Association), low voltage equipment(including grounding system) under 1,000V AC are in the process of change into IEC 60374. IEC 60364 standard will be added to the electrical code(established by Korea Electric Association) in 2007 and amended and after 3-5 years later, it will become a complete IEC 60364. So the purpose of this study is to compare the domestic rail road grounding system and suggest the standardized grounding system for the newly built subway.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1174-1179
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• 2004

In general, the national rail system put an emphasis on distribution planing of stations for smooth operation of transporting goods, train allocation, parking, and maintenance. Since the national rail system is operated on the ground level, it is feasible to improve various aspects of the system during its operation. On the contrary, urban rail system is operated in the limited space under the ground, and thus, improving various aspects of the system during its operation is infeasible. Specifically, the urban subway system must have a comprehensive track distribution plan because the urban subway system has to operate in a limited environment such as it operates in a much shorter time period, The subway system has to be ready for various operations and events such as trains returning in the opposite direction. parking trains that need repair, parking during night time, storing various maintenance equipments, and connections to other tracks. Furthermore, considering the future extension of tracks, a comprehensive track distribution plan is a must.