• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.379-386
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• 2016

As well as to operate a high-speed rail, our country with capability to produce high-speed train has developed a number of techniques, such as for a riding comfort improvement, automatic diagnosis for major electrical or mechanical parts, on board measurement for catenary systems and noise reduction of running rolling-stocks are still under development. In this paper, we describe the current status of operation technologies not only traditional railway wireless communication systems but also Long Term Evolution systems which would be deployed as soon as possible, like as in Europe, China and the United States. In addition, we produced the domestic wireless communication networks for railway which KORAIL Corp. has been operating and the schemes and the plans of HSR field test for the fourth generation mobile communication which should be enforced by national research and development.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.85-90
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• 2011

To maintain the safety and efficiency of railroad vehicles, it is important to understand the working of the brake system with anti-skid control unit (ASCU) for rolling stocks. In this paper, a HILS (Hardware In-the Loop Simulations) system with ASCU hardware (for logic) and a DSP board (for dynamics) is developed to analyze skidding of the Hanvit-200 train during the process of braking. Experimental results are presented for the case that the skid on one of the four wheels is artificially generated using a Simulink model. A convenient GUI is prepared using ControlDesk of dSPACE.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.58-68
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• 2007

Thorough preparations and investigations must be done in order to prevent the hazards which will happen when workers work on the roof of the rolling stocks. Some industrial disasters can be prevented by solving the risks involved in the working of the work processes. Falling accidents tend to happen from the roof of the trains when workers work in the high position. So through the analysis of the 4M( Man. Machine, Media, Management), this paper analyzed the risk factors among the roof works and all problems of the maintenance. Also this paper suggests new devices or new methods to prevent falling disasters and to relieve the mental senses of uneasiness.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1243-1248
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• 2010

Fatigue design and evaluation of welded joints are typically carried out by weld classification approach in which a family (theoretically infinite) of parallel nominal stress based S-N curves are used according to joint types and loading modes as well as extrapolation-based hot spot stress. Traditional finite element methods are not capable of consistently capturing the stress concentration effects on fatigue behavior due to their mesh-sensitivity in stress determination at welds resulted from notch stress singularity. The extrapolated hot spot stresses tend vary, depending on the element sizes, types, joint types, and loading mode. however, the equilibrium-equivalent structural stress method(E2S2) has been recently developed through several joint industry projects as a robust method to analyze welded components using finite element analysis. This method has been proven effective in correlating a large amount of published fatigue test results in the literature such as master S-N curve and has used for evaluating the fatigue life of welding components. In this study, fatigue analysis of the welding bogie frame is examined using E2S2 method with master S-N curve.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.933-941
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• 2010

KORAIL has improved profitability through abolition of nonprofitable route and withdraw rolling stocks, operated at that route. as a part of that process, most sections of commuters' train are gone. presently, gyeongui-line and gyeongwon-line's commuter's trains are operated. Despite the abolition, there are demands for commuters' train. so, nonprofitable route operation policies are needed to meet the demands and connect seamlessly to KTX. In this study, we consider the overall operation policies and problems of commuters' train in the past. and then, we analyze foreign nonprofitable route, connected with high speed train, operation policies and search for the development suggestions for applying to the nonprofitable route between Iksan - jeonju section at Honam and joenra line.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1051-1055
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• 2003

Aluminum carbody for rolling stocks is light and perfectly recycled, but includes severe defects which are very dangerous to fatigue strength. Structural integrity assessment for the carbody by static load test has been performed up to date. In this study, to evaluate fatigue strength of the aluminum carbody of urban transit unit. a testing method to simulate dynamic loading condition was proposed and the fatigue strength of the carbody was evaluated. The dynamic load test results showed that the alternating stress ranges were different from the estimated ranges based on the static test results. Excessive stress ranges at the center are thought to come from the flexible motion of the carbody. published fatigue test data for aluminum components, but variation of alternating acceleration along the length due to flexibility of carbody yielded unexpected results. Because fatigue strength based on the static test results may be overestimated at the center, modification of testing method is necessary.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.536-539
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• 2003

In electric motor coaches, the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the weight of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, the electric motor coach has slip phenomena. This paper proposes a re-adhesion control algorithm which uses the maximum adhesive effort by instantaneous estimation of adhesion force using load torque disturbance observer. Based on this estimated adhesive effort, the re-adhesion control is performed to obtain the maximum transfer of the tractive effort.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1458-1465
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• 2008

With 34 years of accumulated operating experience, Seoul Metro has launched a project aimed at exporting second-hand trains(used EMU cars) to Vietnam while seeking measures for diversifying its business such as the construction of the metropolitan railways both at home and abroad, and operating business as a way of fiscal consolidation and management improvement. Therefore, Seoul Metro has moved ahead with this plan considering that there's no legal constraints on durable period of rolling stocks in advanced countries where the vehicles have been used for 35 years or longer than 40 years through renovation such as safety inspection and comprehensive maintenance program, and the railway systems for the replacement are expected to reach 838 cars by 2015 with growth of 100 cars a year. Seoul Metro strives to create value for boosting revenues and recycling resources by sending used EMUs to Vietnam. Seoul Metro will also provide under-developed countries with cars at a low price as well as share the accumulated railway technical know-how so that it can promote the national image and obtain the pre-emptive effect of metro railways in Vietnam.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.348-356
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• 2004

In this paper, Analysis of parameters effecting on the derailment factor was conducted in oder to deduce technical requisites have to be reflected in design of Track and rolling-stocks because it is important to grasp the risk of derailment quantitatively. And then go far toward becoming practical study with that select two section of sharp curved track of actual train in service, incheon Metro Line 1 and make field research in condition of vehicles and track and analysis As a result of parameter study, the following conclusions were obtained. The radius of curve and Cant is in inverse proportion to the derailment factor, but as train operation velocity, standard deviation of alignment irregularity and the ratio lateral force : wheel load of the inside track increase, the derailment factor rise. In the investigation for the derailment safety of incheon Metro Line 1, the derailment factor was below 0.43 in both section R=200 and R=300, so that it proved safe compare with allowance limits 0.8, but it appeared that risk of the derailment in second transition curve is the highest among the entire curve.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.577-582
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• 2010

The importance of maintenance of rail surface defects is increasing according to the KTX operation. That is because during high speed operation of rolling stocks, rail surface defects shorten fatigue life of rail, accelerate track degradation and deteriorate ride comfort. Rail grinding has been applied for effective rail maintenance in Kyeong-Bu HS line. This paper evaluates the effectiveness of rail grinding in term of rail fatigue life. To this end, the stresses of the rail are measured under KTX running and the equivalent stress range is calculated by RMC after the frequency analysis done with rainflow counting method. Also, The Modified Miner's rule is applied to predict the fatigue life of ground rail. The result of the analysis shows that the fatigue life of ground rail is increased by 15%.