• Proceedings of the KSR Conference
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• 2002.10a
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• pp.214-219
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• 2002

The electric locomotive make a development by using as a trial petition way on the basis of finding for several years in 1996 and the electric locomotive in KNR railway electrification section of AC25KV 60Hz, can couple with passenger train of 700 ton doing running possibility from evenness to maximum running speed 140Km/h, Specially, propulsion equipment operates three phase AC motor that behaves axle control by VVVF inverter and affords higher axle per tractive effort as behaving control by SIBAS32 that up-to-date technology is integrated. Also, new style electric locomotive is designed so that can run in -35∼45 climatic condition.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.129-134
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• 2007

The purpose of this study was to determine the variability of components of the vertical ground reaction force signal to seek the suitable number of attempt datum to be analyzed during running at 2m/s and 4m/s. For this study, six subjects (height mean:$174.5{\pm}4.4cm$, weight $671.5{\pm}116.4N.$, age:$25.0{\pm}yrs.$) were selected and asked to run at least 3 times each run condition randomly. FFT(fast Fourier transform) was used to analyze the frequency domain analysis of the vertical ground reaction forces signal and an accumulated PSD (power spectrum density) was calculated to reconstruct the certain signal. To examine the deviation of the vertical ground reaction between signals collected from an different number of attempt, variability of frequency, magnitude of passive peak, time up to the passive peak and maximum load rate were determined in a coefficient of variance. The variability analysis revealed that when analyze the vertical reaction force components at 2m/s speed running, which belongs to slow pace relatively, it would be good to calculate these components from signal of one attempt, but 4m/s speed running needs data collected from two attempts to decrease the deviation of signal between attempts. In summary, when analyzing the frequency and passive peak of the vertical reaction force signal during the fast run, it should be considered the number of attempt.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.564-573
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• 2009

In this paper, we consider a wireless multiple path network in which a transmitting node would like to send a message to the receiving node with a certain probability of success. These two nodes are separated by N erasure paths, and we devise two algorithms to determine minimum redundancy and optimal symbol allocation for this setup. We discuss the case with N = 3 and then extend the case to an arbitrary number of paths. One of the algorithms minimum redundancy algorithm in exponential time is shown to be optimal in several cases, but has exponential running time. The other algorithm, minimum redundancy algorithm in polynomial time, is sub-optimal but has polynomial worstcase running time. These algorithms are based off the theory of maximum-distance separable codes. We apply the MRAET algorithm on maximum-distance separable, Luby transform, and Raptor codes and compare their performance.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.420-423
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• 2003

A low temperature difference model Stirling engine is a small Stirling engine running with several degree of temperature difference without power output. In this study, the design parameters to give maximum power are discussed. As results, the phase angle is about 100 degree, and compression ratio is 1.5% of the ratio of heat source temperatures at maximum power condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.941-949
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• 2011

When a railway vehicle passes through curves & transitions, the running speed must be improved by setting limits on the maximum running speed in each section of the conventional line(Dongdaegoo-Namsunghyun) considering derailment safety. Our goal is to improve the maximum running speed of railway vehicle that passes through curves & transitions where there is a high risk of derailment. We examined the influence on the derailment safety when the railway vehicle passes through curves of actual track conditions (Dongdaegoo-Namsunghyun up and down lines). We performed the derailment safety analysis by increasing the running speed on curve radius by 5%.20% compared to existing speed under actual track conditions.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.192-198
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• 2004

KTX is the high speed train which is designed for 300km/h in maximum operation speed. But its long train set may cause unstable characters as swaying of the tail of a train and when the train is running on conventional line not on the high speed line, its funning safety is a point to be considered cautiously. In this study, we evaluated the running safety by the numerical analysis using VAMPIRE and compared the result with the test result of KHST, which is being in performance tests, for verifying the validity of analysis results.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.6
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• pp.629-636
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• 1988

The reduction of recovery time for delay, in the train movements, is generally realized through train operations in the shortest running time and it leads to maximum energy consumption. At the region of this shortest running time, the amount of energy consumption is sharply reduced according to the running time. So the effect for the energy savings can be largely obtained by furnishing a little spare time on train operations. In this paper, it has been modelized the delay and it's enlargement phenomena and formualted the relief patterns in order to restore the delay by restraint and relief of precedent traints. Also it has been proved the number of relief trains for minimum energy consumption exists and then represented one example of relief patterns.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.554-560
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• 2003

The transmission systems of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the capability of reduction gear unit for Korea High Speed Train, torque and temperature, vibration on the reduction gear unit were measured and test data were analyzed. This paper reports test methods and test results that performed to verify reliability of reduction gear unit during running test of Korea High Speed Train. It is confirmed from these results that the performance of reduction gear unit has not any problem.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.57-60
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• 2004

A domestic's freight stock is about 14,000 cars. Most of them is consisted of casting bogie type. Casting bogie type has some problems such as maintenance, part abrasion, running safety etc. Now a day casting bogie type have replaced with welded type bogie for high speed. The maximum speed of the container freight car is 70km/h limit at empty weight condition in case of casting type bogie frame. So there are some difficulty in commercial service for high speed coaches. Then we should re-decide whether the casting bogie type has speed up 90km/h limit at empty weight through out the vibration characteristic.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.161-168
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• 1998

This paper presents an simulation methdology for determining an economical running pattern for a high speed train which minimizes energy consumption under an given trip time margin. The economical running pattern is defined with an economical maximum speed in traction phase, a speed at the end of coasting and a speed at the end of regenerative braking alone in braking phase. An economical run for subways is also described. As a case study, the simulation is carried out fer an economical run of high speed NamSeoul-Pusan line, and the results described. To do this, train performance simulation program is built and extended to be able to find an economical running pattern and then to simulate the defined economical run.