• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2426-2441
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• 2008

This research is analyzed by the operation frequency of Regional Railroad and the Load Factor on the level of each service based on the Regional railroad ticket sales data on the 2007 fiscal year. Because the Regional Railroad passenger's satisfaction is sensitive of the transportation demand alteration, this research analyzed LOS. In addition to, analyzed the LOS will affect driving patterns of the Regional Railroad.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.23-29
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• 2008

The railway system is worldwide recognized as a safe mean of transportation. However, railroad accidents and incidents continue to occur. Due to the nature of the railway system that consist of many mechanical parties, it is apparently difficult to eliminate probability of accidents and incidents completely. Therefore, through the analysis of railroad accidents and incidents, it is very important to trace the various factors affecting the accidents and incidents. In this study, we performed the analysis of rail-road accidents due to track defects in foreign countries; United States of America, England, Canada, Australia. As a result of its investigation of the accidents, major risk factors are proposed in this study.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.229-236
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• 2017

The railway has recently been expanded with the phase of the future transportation. Accordingly, using the new technologies such as smart devices and LTE-R, the needs for reducing operational costs and improving passenger services have emerged. To realize these needs, the government is pushing to build the dedicated wireless network for the railway systems. In this paper, the shunting route indicator was selected for this study because it has the best effect for the wireless system removed lots of wired cables. And the wireless shunting route indicator applied with LTE-R technology was developed to replace the current wired control system. The functional goal(the wireless control function applied LTE-R), the performance goal(less than 300ms for transferring the control information), and the reliability goal(over the 100,000 hours for MTBF) were set, and these goals were achieved and demonstrated through the test and validation.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.357-363
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• 2021

Eco-friendly hybrid railroad propulsion system with fuel-cell and battery was suggested to reduce carbon dioxide gas and replace retired diesel railroads. Lithium-ion battery with high energy/power density and long lifetime is selected as the energy source at the battery side due to its excellent performance. However, the performance of lithium-ion batteries was affected by temperature, current rate, and operating condition. Temperature is known to be the most influential factor in changing battery parameters. In addition, appropriate thermal management is required to ensure the safe and effective operation of lithium-ion battery. Electro-thermal coupled model with varying parameter depends on temperature, and state-of-charge (SOC) is suggested to estimate battery temperature. The electric-thermal coupled model contains diffusion current using parameter identification by adaptive control algorithm when considering thermal diffusion effect. An experiment under forced convection was conducted using cylindrical cell and 18 parallel-connected battery module to demonstrate the method.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1777-1782
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• 2007

Since July in 2004, starting with urban bus reorganization of Seoul metropolitan government, the change of the public transportation which integrates the urban bus and the subway of the metropolis are being continued. But the integration of such bus and the subway is staying to only a fare system mainly, and the guidance system of the subway and the bus has not changed. So we propose the concept of the new guidance system following public transportation change tendency. At first we introduce the new information system which can guide city railroad and bus altogether, and we propose new system which can guide divided by the trunk line and the branch line instead of bus and subway. Last high-functional guidance system which can give passengers tip and hint for various and effective usage of public transportation in more complicated city transit network is introduced. This new guidance system can increase competitiveness of public transportation system and stretch transportation share of it. And that guidance system is high-class contents that all public transportation business can utilize, so it can originate new industry. In conclusion, this new innovative guidance system is important field that government, local administration and public transportation business must be concerned and develop.

• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.327-335
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• 2014

The Korean government, as of last year, is attempting to introduce a competitive system in the rail-market. However there are some pertinent issues which need to be addressed in order to select the best possible organization for optimum railway traffic control. As there are no standard guidelines in selecting an agency, objective evaluation factors need to be properly applied to ensure the best possible decision is made. Through literature review and various interviews with experts, appropriate criteria were selected to evaluate the suitability of each potential operator. As generally mentioned, both safety and efficiency play vital roles in the selection process but in addition, there are other factors such as security and fairness, which also need to be considered. The individual weight of these factors were calculated by the AHP, in which three groups of experts were interviewed to acquire their expertise. According to the results, as a potential operator, the score of a railway operating company and the management cooperation of railway is 2.75 and 3.85, respectively. In the future, in preparation towards becoming a competitive rail-market, this research is expected to assist in choosing the best party to control the rail traffic system.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.408-412
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• 2012

Recently, new climate change mechanism after 2020 year has been accepted with the parties, and so government is pushing ahead the GHG reduction policies to achieve the effective results. Especially, it is essential to enhance the role of railroad in the public traffic system as well as to develop new cars with high energy efficiency for the GHG reduction of transportation sector. Thus, the calculation method of GHG emission of railroad should be established to manage the emission continuously. In this study, the calculation method of GHG emission of railroad was defined with Tier level considering its emission sources to refer to 2006 IPCC guideline for national GHG inventories. Also, the GHG emission of railroad at Tier 1 level was investigated using the activity data related to the amount of diesel and electricity consumption from 2008 to 2010. As a result, total GHG emission in 2010 was about 2,060 thousands ton CO2e, which have 73% of electricity and 27% of diesel. In future, the plans on the GHG reduction of railroad will be accomplished by the analysis of the detailed trends on the basis of the emission management of Tier 3 level under operating patterns. Therefore, it is important to develop the specific GHG emission factors of railroad in advance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7934-7940
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• 2015

The raise of the acceleration can be one of possible methods to increase the scheduled speed of the metropolitan railway system. It is possible to raise the acceleration to the some point by increasing the traction power of the motor. However, there is a limit of the acceleration because the traction power over some level related to the adhesion causes a slip, which prevents from accomplishing the target acceleration. The running resistance is also an important factor to consider. Both the adhesion and the running resistance as well as the traction power vary according to the velocity. Therefore, the standardization of the acceleration needs the analysis of these factors as a function of velocity. In this study, we focus on the advanced urban transit unit(AUTS) for the standardization. We derive a novel equation of the adhesion suitable for the AUTS by investigation of the traction and adhesion equation as well as the experiment data. And finally we propose the standard of the acceleration based on this analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1577-1582
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• 2016

Now we are facing severe environmental issues such as global warming. Due to these, the concerns about eco-friendly energy have been increased. Kyoto protocol and Copenhagen climate change conference are circumstantial evidence of it. With these trends, the interests for the Electric Vehicles(EVs) which do not emit any harmful gases have gradually been raised. Unfortunately, however, massive connection of EVs to the power system could cause negative impacts such as voltage variations, frequency variations and increase of demand power. To prevent the mentioned issues, KEPCO adopts Time-of-Use(ToU) price for EVs charging. Nevertheless, it is important to verify the propriety of the charging system. In this paper, therefore, we used pre-introduced price elasticity concept to predict possible Demand Response(DR) on charging of EVs. And analyzed possible demand power increase according to various price elasticities. Simulation results show that given ToU based charging system would not enough to control the increase of demand power by EVs on the power system. It is concluded, therefore, additional methods and/or algorithms are required.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.6
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• pp.948-953
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• 2015

In this paper, we studied the environmental requirements for the railway transponder system. The transponder system is comprised of a reader installed beneath the train, a tag installed on the track, and a portable programmer. Among them, the transponder tag should be designed to withstand harsh environments, such as wide operating temperature range, mechanical shock and vibration, etc. To validate stable and reliable service under railway conditions, we carried out environmental test for transponder tag. We then installed the tags on the Honam high-speed test line.