• Journal of the Korean Geotechnical Society
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• 제36권3호
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• pp.5-14
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• 2020

The railway concrete track has been increasingly adopted for high-speed train such as KTX due to its high running stability, improved ride quality for the passengers, and low maintenance cost. However, excessive settlement of the railway concrete track has been monitored at embankment sections of the ◯◯ High-speed Line, resulting in the concerns on the safety of railway operation. In order to establish an effective maintenance plan for the concrete track railway exceeding the allowable residual settlement, it is essential to reasonably predict their long-term settlement behavior during the public period. In this study, we developed a model for predicting the long-term settlement behavior of concrete track using recurrent neural network (RNN) and examined the applicability of the developed model.

• The Journal of the Convergence on Culture Technology
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• 제10권1호
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• pp.579-584
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• 2024

Currently, large-scale, deep construction is being carried out adjacent to subway tracks in korea. when excavating adjacent to each other, it is very important to ensure the safety of earth retaining structures and underground structures. therefore, we are managing the safety of the subway by introducing an automated measurement system. deformation of the subway track during adjacent excavation may affect train running stability. this is a factor that can be linked to train derailments. however, current subway track safety evaluation using automated measurement systems relies only on the maximum value of measured data. therefore, a method to improve the usability of automated measurement system results is needed. in this study, we utilized a technique that can quantitatively evaluate the measurement results of a large amount of subway track deformation. a safety evaluation was conducted on subway track deformation due to adjacent excavation using a vast amount of data using probabilistic statistical analysis techniques.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권12호
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• pp.8516-8524
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• 2015

Track irregularities can be evaluated not only directly by track inspection but also indirectly by measurement of carbody accelerations and many researches are being conducted. Carbody accelerations were measured on the Kyeongbu high speed railway and France high speed line to investigate the situation of the track maintenance at Korea high speed line by using indirect method. Digital signal processing for the measured acceleration data were conducted according to UIC518 code. Since the vehicle speed affects the car body acceleration, the lateral and vertical acceleration of the car body were classified according to the vehicle speed and the distribution characteristics of these acceleration were investigated and evaluated by UIC518 criteria. Finally, the running behavior of KTX on Korea high speed railway were compared with that on France. Distribution characteristics of these acceleration were evaluated and discussed in terms of the track maintenance in Korea high speed line.

• Korean Journal of Applied Biomechanics
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• 제31권4호
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• pp.241-248
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• 2021

Objective: The purpose of this study was to investigate the difference in muscle strength, kinematics, and kinetics between injured and non-injured sides of the leg after Achilles Tendon Rupture surgery during walking and running. Method: The subjects (n=11; age = 30.63 ± 5.69 yrs; height = 172.00 ± 4.47 cm; mass = 77.00 ± 11.34 kg; time lapse from surgery = 29.81 ± 10.27 months) who experienced Achilles Tendon Rupture (ATR) surgery participated in this study. The walking and running trials were collected using infrared cameras (Oqus 300, Qualisys, Sweden, 100 Hz) on instrumented treadmill (Bertec, U.S.A., 1,000 Hz) and analyzed by using QTM (Qualisys Track Manager Ver. 2.15; Qualisys, U.S.A). The measured data were processed using Visual 3D (C-motion Inc., U.S.A.). The cutoff frequencies were set as 6 Hz and 12 Hz for walking and running kinematics respectively, while 100 Hz was used for force plate data. Results: In ATR group, muscle strength there were no difference between affected and unaffected sides (p> .05). In kinematic analysis, subjects showed greater ROM of knee joint flexion-extension in affected side compared to that of unaffected side during walking while smaller ROM of ankle dorsi-plantar and peak knee flexion were observed during running (p< .05). In kinetic analysis, subjects showed lower knee extension moment (running at 2.2 m/s) and positive ankle plantar-flexion power (running at 2.2 m/s, 3.3 m/s) in affected side compared to that of unaffected side (p< .05). This lower positive ankle joint power during a propulsive phase of running is related to slower ankle joint velocity in affected side of the subjects (p< .05). Conclusion: This study aimed to investigate the functional evaluation of the individuals after Achilles tendon rupture surgery through biomechanical analysis during walking and running trials. Based on the findings, greater reduction in dynamic joint function (i.e. lower positive ankle joint power) was found in the affected side of the leg compared to the unaffected side during running while there were no meaningful differences in ankle muscle strength and walking biomechanics. Therefore, before returning to daily life and sports activities, biomechanical analysis using more dynamic movements such as running and jumping trials followed by current clinical evaluations would be helpful in preventing Achilles tendon re-rupture or secondary injury.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.435-442
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• 2000

In this thesis the dynamic behavior of the vehicles is analyzed while the track is subjected to lateral vibration due to earthquakes. A computer program is developed which can simulate dynamic responses of vehicles subjected to earthquake loading. The analysis considers two types of two types of vehicles : I. e. a 2-axle vehicle with 13 DOF's an da power car of K-TGV with 38 DOF's It can also consider the interaction with substructures such as tracks and bridges. El Centro record is considered as earthquake loading. The creep force module developed in this study is verified and the results of this study are compared with those of others. Furthermore he running safety of high-speed railway vehicles(K-TGV) subjected to earthquake loading is studied. Based on the results of this study the running safety of the K-TGV can be confirmed against el centro earthquake.

• Proceedings of the KSR Conference
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1069-1073
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• 2011

When the train is running on the small curved line, there would be severe contact between the rail and wheels, which cause noise and vibration as well as abnormal wear on the rail and the wheels. In order to solve these problems, the steering bogie has been developed. To verify steering performance of the steering bogie, steering angles of two trains, one is the advanced EMU with the steering bogie, another is a conventional EMU with the conventional bogie, were measured while running on the small curve. this comparing test shows that the steering bogie has much higher steering performance than the conventional bogie on the same curved line. To verify more performance data of the steering bogie, further testing and monitoring will be done with the advanced EMU in the test track.

• Proceedings of the KSR Conference
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1881-1887
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• 2011

The speed-limit regulation on the turnout is the main cause which hinders the speed-up of conventional lines among many factors. The specification speed for the train which passes the turnout system is lower than that on the general track. In this paper, shape of guard rail of Daegu Metropolitan Transit Corporation was investigated, and the effect of the variation of guard rail length on the running safety of a vehicle was analyzed for the purpose of speed improvement on turnout using the developed analysis method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.340-345
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• 2002

Passengers in automobile or train are exposed to a worse noise environment when they are in the tunnel than in the open field. This is due to a relatively higher space density of sound energy by multiple reflection phenomenon of noise generated by operation of transportation vehicles from tunnel wall compared to open field. In this study, noise characteristics of subway train running through a tunnel were investigated at straight/curved track and tunnel type(semi circular/box). Also the noise measured simultaneously at inner and outer sides of train running through a tunnel, so that the coherence of the various noise sources of subway train to inner noise was evaluated.

• Proceedings of the KSR Conference
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1100-1105
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• 2010

The high speed line and conventional line are a single-phase AC feeding system; and power supplies of different phases meet at SS(SubStation)s or SP(Sectioning Post)s. These sections should be negotiated with the main circuit breaker in the traction vehicle switched off, whereby the length of the neutral zone prevents the pantographs shunting adjacent overhead line section. In order for electric railway vehicles to make power running there, there must be a power supply changeover section (approx. for 1km), where a changeover switch changes a power supply to the other power supply of a train running direction sequentially. For a thorough changeover switching control, the precise train position detection is necessarily required. In this paper, to realize the ground-based train position detection method, configuration scheme of train position detection equipment is suggested by using track circuit and axle counter.

• Proceedings of the KSR Conference
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.229-235
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• 2007

The KTX, which have opened the revenue service in April 2004, is operating in Kyoung-Bu high-speed line and electrified conventional Ho-Nam line, and the more the electrification are enlarged, the more the requirement of operating of high speed train would be increased. In this paper, the result of test run and evaluation on the suitability of operating high speed train in electrified conventional line between Dae-jeon and East Dae-gu was reviewed. Evaluation and analysis was executed in specific categories, such as operation & running performance of the train considering vibration characteristics based on UIC 518, ride comfort and current collection, and response sensitivity of ATS device for signalling from track facility. The result of this running test was evaluated and considered as a good practice for revenue operation of high speed train in electrified conventional line between Dae-jeon and Dae-gu.