• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1370-1376
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• 2008

The structure of railroad or subway is that low fare transportation system of the large traffic volume. Like this structure is subjected to the cyclic load of moving vehicle. Consequently the result of the settlement analysis or plastic deformation prediction of railroad bed could be used as an important factor in safety of the railroad. The results of cyclic triaxial test were used in the numerical analysis of power model which Li and Selig(1994) developed. The soil samples were obtained from the construction site of railroad. Cyclic triaxial test was conducted with the variation of the magnitude of cyclic load and soil types. The large magnitude of plastic deformation in the railroad bed is caused of structure failure of the railroad.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.94-99
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• 2014

Recently, trends in new transportation system development have been primarily focused on sustainable and ecofriendly mobility solutions. The personal rapid transit (PRT) system has been considered a promising candidate in this category; its competitiveness is being improved through convergence with cutting-edge electric vehicle (EV) technologies. However, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. In this study, a design approach for a solar-power assisted PRT system is presented with small-scale demonstrations aimed at circumventing challenges facing its adoption, as well as helping speed the transition to electric-powered ground transportation. From the results, it is expected that flexible photovoltaic (PV) cells will be able to supply 11% of the power required by the service equipment installed in a prototype vehicle. In particular, flexible photovoltaic (PV) cells are advantageous in terms of cost, weight, and design considerations. Most importantly, the cells' flexibility and attach-ability are expected to give them great potential for extended application in various areas.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.11
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• pp.570-579
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• 2017

In this study, we examined the multi-stage piston-type air compressors typically used in a railroad vehicle, and the heat transfer efficiency was analyzed according to the design conditions of the heat exchanger (a compressor component module for cooling the compressed high temperature air). For the fin-tube heat exchanger used in the most air compressors, numerical analysis was performed to analyze heat transfer by defining the various rectangle tube sizes and the number of fin-per-unit area as design variables under the same flow rate of compressed air. Also, this analysis compared the temperature of the compressed air. Regarding environmental conditions for analysis, the flow rate of the external cooling air was measured and the mean value of the values was applied. And a "turbulence model" was considered in both the external flow of the cooling air and the internal flow inside the tube. From the results of analysis, it was found that the change of the aspect ratio value of the tube greatly influences the heat transfer efficiency of the compressed air, and influences if the fin density is relatively small. As a result, the optimum design specifications of the heat exchanger for air compressors were confirmed based on the analysis of the heat transfer efficiency, according to the design conditions of fin and tube by the operating temperature range of the compressed air.

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.110-116
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• 2013

Track irregularities is one of the key factors influencing the running behavior of trains. In order to ensure safety and ride comfort of train, the criteria for track irregularities should be adequately established regarding vehicle velocity, vehicle characteristics, characteristics of the track recording car, and measurement interval. Also, track maintenance should be carried out thoroughly according to the criteria for managing track irregularities. Numerical analysis was conducted to investigate the influence of track alignment on the running behavior of Korean high speed train(KTX). Various wavelengths and amplitudes of lateral alignment were considered as parameters for this study using the Vampire program, a vehicle dynamics modeling package in railway environment. Derailment, lateral load, bogie acceleration and body acceleration of numerical analysis results due to alignment were investigated. Finally, the influence of the alignment on safety and ride comfort for the KTX was evaluated. This study indicates that alignment irregularities have significant impacts on running safety, and that the criteria used to manage alignment irregularities should be restrictive to ensure the running safety of the KTX.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.3
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• pp.199-208
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• 2013

So far today, there is a speed limit by the radius of curve based on operation regulation in domestic railway, however a study for the maximum running speed at the curved section without any derailment would be necessary. The two major factors related to the running safety of railway vehicle are classified as the railway vehicle condition and the track condition. In terms of the rail inclination among many other factors, the determination of rail inclination within the possible limit is necessary for the geometrical structure of the optimum track. The disregard of the geometrical parameter related to the rail inclination may cause a serious problem to the running safety of railway vehicle. This study is focusing on the analyzing of running safety regard to the change of rail inclination among the many other parameters to improve derailment safety, so that there is an affection analysis of the running safety regard to the change of rail inclination in the ideal and geometric track condition. Also There is an affection analysis of the running safety regard to the simultaneous change of rail inclination and the running speed at the curved section. According to analysis results of running safety, In case that the left and right rail inclination are 1/40, the running safety of this condition defined than other conditions. Also, the rail inclination of conventional lines is 1/40, Therefore, the railway vehicle passing through curve is safe when the railway vehicle runs in conventional lines.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1497-1503
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• 2016

This paper presents the overall measurement system for on-line test of super-speed maglev train. The super-speed maglev train is composed of vehicle, propulsion, power, and so on. In order to evaluate and diagnose for sub-system, we made overall measurement system. Just like the other measurement system, it is designed to distributed type. The hardware is consist of SCXI, PXI, Terminal, UPS, and so forth. It is installed on a train, control room, power room and track to collect lots of signals. The software controls hardware system, monitors main data such as inverter current, converter voltage. Using the measurement system, we evaluated a lot of performances for vehicle, track, and so forth. Through the developed system have improved reliability and safety for super-speed maglev train.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.2
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• pp.133-139
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• 2014

Magnetic Sensors can be employed to localize the unmanned vehicle which is running a predefined path where magnets are embedded for certain spaces. Among various sensor types, sensor arrays of 1-dimensional magnetic sensor have the merit of easy elimination of external magnetic component such as terrestrial magnetism. However, interpolation should be considered in the array sensors in order to increase the precision level because there is a limit in arranging sensors in close interval. We propose the novel interpolation method which can be performed with simple computation and represents the improved accuracy by increasing the linearity of the interaction formula. Demonstration of the linearity and simulation results show the proposed method exhibits the improved accuracy compared to the conventional method.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1789-1797
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• 2017

It is necessary to charge electric vehicles in order to drive them. Thus, it is essential to have electric vehicle charging facilities in place. In the case of a household battery charger, the power similar to that consumed by a household with a basic contract power of 3kW is consumed. In addition, many consumers who own an electric vehicle will charge their vehicles at the same time. The simultaneous charging of electric vehicles will cause the load to increase, which then will lead to the imbalance of supply and demand in the distribution system. Thus, a smart charging scheme for electric vehicles is an essential element. In this paper, simulated conditions were set up using real data relating to Korea in order to design a smart charging technique suitable for the actual situation. The simulated conditions were used to present a smart charging technique for electric vehicles that disperses electric vehicles being charged simultaneously. The EVs and Smart Charging Technique are modeled using the Electro Magnetic Transients Program (EMTP).

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.175-177
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• 2008

The level crossing collision accident which comprises more than 90 percent of all level crossing accidents is one of the most serious safety problems. There is a critical need for providing safe strategy and is focusing on the level crossing information rather than measures at a grade crossing. This study is intended to develop technology for accident prevention and damage reduction based on accident cases analysis result and improvement direction to complement shortcomings of safety equipment of conventional level crossing and to establish safety of travelers(train, motor vehicle, person).

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.435-437
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• 2003

Recently, as the road capacity reaches the limit and environmental problems becomes serious, there is gradually increased a need for railroad vehicles that are environment-friendly and have time regularity, reliability and safety. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. We developed the hardware and software of the measurement system for on-line test and evaluation of korean hish speed train. The software controls the hardware of the measurement data and acts as interface between users and the system hardware. In this paper, we is studied for electric apparatus performance of railway vehicle using sensor. In order to this test is developed signal conversion system. Using this system, we obtained important result for pantograph voltage, battery voltage, axle speed, and running speed.