• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.426-438
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• 2015

Train speed controlling systems are now changing from wayside systems to onboard signaling systems. Locomotive engineers refer to wayside markers to decide on a braking point when the train speed appears to be lower than the current speed. However, in the onboard signaling systems that have been installed recently, the braking point is not determined by the wayside signal but by an onboard value. In this paper, we studied braking points and methods for deciding on such points by engineers using the onboard systems. An optimized braking point is proposed via simulation of decelerating velocity to control the velocity in the signaling system through a predefined point; Gaussian distributions are used to simulate the actual situation. We estimated and demonstrated how to obtain braking parameters in order to satisfy the interval of permitted error.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.225-233
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• 2006

Creating more efficient and effective intermodal transportation service in Northeast range is a critical issue because of more increased trade volume & demand for intermodal service in the world market and geographical barriers associated with goods transportation, especially in Korea, China and Japan. This study examines the possibility of Rail-ferry in Northest area which can provide each countries mutual economical and logistical satisfaction.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.3
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• pp.213-218
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• 2020

In this study, we propose a control algorithm to reduce the unbalanced characteristics of a three-phase system power caused by the unbalanced load of the AC electric railway. Then, we verify its performance through the design of a power compensator and experiments applying it. Like electric railway systems, a Scott transformer is applied, and the load and single-phase back-to-back converters are connected to the M-phase and T-phase outputs. The back-to-back converter monitors the difference in active power between the unbalanced loads in real-time and compensates for the power by using bidirectional characteristics. The active power is performed through PI control in the synchronous coordinate system, and DC link overall voltage and voltage balancing control are controlled jointly by M-phase and T-phase converters to improve the responsiveness of the system. To verify the performance of the proposed power compensation device, an experiment was performed under the condition that M-phase 5 kW and T-phase 1 kW unbalanced load. As a result of the experiment, the unbalance rate of the three-phase current after the operation of the power compensator decreases by 58.66% from 65.04% to 6.38%, and the excellent performance of the power compensator proposed in this study is verified.

• Journal of Korean Society of Transportation
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• v.33 no.6
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• pp.531-542
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• 2015

The discussion about the structural reformation of Korean rail industry has been consistently conducted from the evaluation on Korean National Railroad's management in 1998, the foundation of KORAIL in 2005 to the approval of Suseo KTX corporation establishment in 2013 and the controversy over its privatization. This research explores the changes of government policies by applying to ACF in the assumption that those changes have been implemented due to the interaction of various external variables and main agents in policy which had existed for a long-term period that the rail industry's structural reformation has been practiced for more than 10 years. The unions failed to reach an agreement for the rail industry's structural reformation, the policies regarding the reformation have been led by superior political unions. And this research concludes that a mediator who can compromise unions' different policy preferences and means and bring up a compromised decision in conflicted situation plays a pivotal role to successfully practice these policies.

• Journal of Distribution Science
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• v.8 no.2
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• pp.5-12
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• 2010

The allotment rate for railway transportation keeps an yearly 6% in Korea. However, the railway logistics will cause the opposite result according to the continuous investment and logistics rationalization. The study on railway logistics as well as inter-Korean railway that might highly contribute to the development of railway logistics is not enough at all. The purpose of this paper is to study the revitalization strategy for inter-Korean railway by forecasting the demand and the scale of railway logistics depot. The revitalization strategies for inter-Korean railway through railway logistics depot are as followings. First, it is necessary to strengthen the partnership with coal user in the logistics depot. Second, it is encouraged to provide the financial assistance that are needed in the maintenance of the decrepit North Korea's track as well as the establishment of Donghae northern line that is from Gangneung to Jejin. Third, the railway cost on long/short transportation and large sized shipper is needed to apply in a flexible way. Fourth, it is necessary to obtain the railway traffic right by involving the foreign mining development. Fifth, it is encouraged to constantly find the small sized shipper like cement company.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.37-41
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• 2019

The following study, as the importance of military role in a national disaster is emerging as a part of comprehensive security, there has been a number of elements of social disaster-related support in support of each type of national disaster aimed to improve the military's role towards comprehensive security but there has been no regular study of this topic. The point of this study is to analyze various aspects and hardships during the mission and improve the effectiveness of future support missions by observing and interviewing the military personnel which substituted the role of train drivers in the Seoul Metro in 2016, when the Korean Railroad Corporation [KORAIL] Workers Union was on strike [72 days] which is the longest period of a national disaster requiring military assistance.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.272-277
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• 2012

KORAIL's logistics business coefficient is improved slightly from 197.4 in 2009 to 190.7 in 2010 but the cost is still high compared to the revenues. In order to derive activities for the efficient logistics and measure their effects quantitatively, the analysis of various indexes that can be extracted from the statistical data is very important. In this study, the various indexes are analyzed to evaluate the efficiency of freight cars based on railway logistics. It can be used to estimate the various activities for the efficient logistics associated with freight cars. We suggest the Indexes as the number of transport, cumulative transport distance and transport income to evaluate the efficiency of freight cars and they should be applied according to the characteristics of each index.

• The Korean Journal of Archival Studies
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• no.30
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• pp.125-174
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• 2011

Railway Station in Korea built for purpose to plunder resource and invade China 19 and 20 century early, It functioned as main transportation and important role in local history. However, Since the late 1990s, Railway Station in Korea is facing major changes due to Railroad Improvement and Restructuring plan. Photography is useful way to represent memory and local history about railway station, but Photography Documentation on railroad station were not discussed until now due to indifference of the KORAIL and peculiarities of national security facilities for a long time. This study suggest what is document activities and facilities of railway station, use value analysis about railway station's value firstly. next, this study set each documentation area with value analysis for a basis and present concrete example. finally, this study adapt documentation area and detail to classification scheme and apply activities and facilities of supplement or revision to classification scheme.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.833-843
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• 2016

Recently, in the field of rail freight transportation, the number of trains dedicated for shippers has been increasing. These dedicated trains, which run on the basis of a contract with shippers, had been restricted to the transportation of containers, or so called block trains. Nowadays, such commodities have extended to cement, hard coal, etc. Most full freight cars are transported by dedicated trains. But, for empty car distribution, the efficiency still remains questionable because the distribution plan is manually developed by dispatchers. In this study, we investigated distribution models delineated in the KTOCS system which was developed by KORAIL as well as mathematical models considered in the state-of-the-art. The models are based on optimization models, especially the network flow model. Here we suggest a new optimization model with a framework of the column generation approach. The master problem can be formulated into a transportation problem with additional constraints. The master problem is improved by adding a new edge between the supply node and the demand node; this edge can be found using a simple shorted path in the time-space network. Finally, we applied our algorithm to the Korean freight train network and were able to find the total number of empty car kilometers decreased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8700-8706
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• 2015

The first driving device of the power bogies for the Korean high-speed railway vehicle consists of the traction motor (TM) and the motor reduction gears unit (MRU). Although TM and MRU are the mechanically integrated structures, their time between overhauls (TBO) have two separate intervals due to different technical requirements(i.e. TBO of MRU: $1.8{\times}10^6km$, TBO of TM: $2.5{\times}10^6km$). Therefore, to reduce the unnecessary number of preventive maintenances, it is important to evaluate the optimal TBO with a viewpoint of reliability-center maintenance towards cost-effective solution. In this study, derived from the field data in maintenance, fault tree analysis and failure rate of the subsystem considering criticality of the components are evaluated respectively. To minimize the conventional total maintenance cost, the same optimal TBO of the components is derived from genetic algorithm considering target reliability and improvement factor. In this algorithm, a chromosome which comprised of each individual is the minimum preventive maintenance interval. The fitness function of the individual in generation is acquired through the formulation using an inverse number of the total maintenance cost. Whereas the lowest common multiple method produces only a four percent reduction compared to what the existing method did, the optimal TBO of them using genetic algorithm is $2.25{\times}10^6$km, which is reduced to about 14% comparing the conventional method.