• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1855-1860
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• 2007

The high speed tilting train has superior advantages which are effects on reductions of running time to non-tilting in curves. But in order that the tilting train is operated in conventional track, it is performed evaluation on the running safety. This study carried out an analysis of running stability of tilting train in conventional curved track. The results obtained through this study will be applied to improve the conventional curved track and determine the limit velocity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1031-1035
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• 2007

When vehicles running, vertical force and lateral force act except load of vehicles to rail and wheel. This force happens by complex motion at running. If mark vertical force by P and lateral force by Q, derailment coefficient displays Q/P, most important indicator pointer of running safety judgment. If Q is grown than P from derailment coefficient, than arrived to derailment because wheel climb or jumps over rail. Wheel climb derailment among kind of derailment is when attack angle is +, wheel and rail strike and flange rides to rail. This derailment occurs much in curved line and occurs in low speed. In this study, occurred when running at low speed on curved line, analyze cause of derailment and presented the countermeasure plan.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.773-778
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• 2008

The subway noise in curved line is affected not only by rail condition but also wheel condition and dynamic characteristics. The railway curving noise can be divided into 2 categories. The first is noise depending on the vehicle speed, and the second is the one independent on vehicle speed. In this study the noises were reviewed by using eigen-mode of wheel and waterfall plot which shows noise level in time-frequency domain. And also those were reviewed in viewpoint of stick-slip noise and wheel flange contact noise.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1224-1228
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• 2009

The korean tilting train can increase the whole operating speed at a curved railroad, reducing the lateral acceleration with the tilting mechanism unlike the train developed before. However, increasing operating speed on the curved section, may cause safety problem of train travel. In general, a suspension system has important effects on driving safety. Therefore, optimization of suspension system is necessary to secure the safety of the tilting train. In this study, the tilting train suspension system has been optimized using Design of Experiments (DOE). First, the design parameter is selected using sensitivity analysis. A lateral acceleration which affects on the driving safety is chosen as the objective function. And the Design of Experiments (DOE) is used for optimization. As a result, new design parameters which show better performance than the existing suspension system has been suggested.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1587-1591
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• 2009

Safety of railroad is result of reliability which is received from test & evaluation of system. Railroad system is consisted of various sub system such as vehicle, supply of electric power, signal, communication, rail track construction, operation. To secure safety of railroad, evaluation about parts, assembly, sub system, whole system etc.. that compose railroad is essential. In this paper, I wish to describe for results that analyze korean tilting vehicle's derailment coefficient developed by national research achievement. Result that evaluation korean tilting vehicle's running safety, verified that secure even if speed-up 30 km/h than operating speed of present in curved track.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.295-302
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• 2001

The lateral stability of curved continuous welded rail (CWR) is studied fur buckling prevention. This study includes the influences of vehicle induced loads on the thermal buckling behavior of straight and curved CWR tracks. quasi-static loads model is assumed to determine the uplift region, which occurs due to the vertical track deformation induced by wheel loads of vehicle. Parametric numerical analyses are performed to calculate the upper and lower critical buckling temperatures of CWR tracks. The parameters include track lateral resistance, track curvature, longitudinal stiffness, tie-ballast friction coefficient, axle load, truck center spacing, and the ratio of lateral to vertical vehicle load. This study provides a guideline for the improvement or stability for dynamic buckling in on tracks.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1165-1170
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• 2005

In order to perform the spatial buckling analysis of the curved beam element with nonsymmetric thin-walled cross section, exact static stiffness matrices are evaluated using equilibrium equations and force-deformation relations. Contrary to evaluation procedures of dynamic stiffness matrices, 14 displacement parameters are introduced when transforming the four order simultaneous differential equations to the first order differential equations and 2 displacement parameters among these displacements are integrated in advance. Thus non-homogeneous simultaneous differential equations are obtained with respect to the remaining 8 displacement parameters. For general solution of these equations, the method of undetermined parameters is applied and a generalized linear eigenvalue problem and a system of linear algebraic equations with complex matrices are solved with respect to 12 displacement parameters. Resultantly displacement functions are exactly derived and exact static stiffness matrices are determined using member force-displacement relations. The buckling loads are evaluated and compared with analytic solutions or results by ABAQUS's shell element.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.72-79
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• 2006

Derailment is likely to have a direct connection with human life and must be eliminated. A traveling safety evaluation method based mainly on derailment coefficient has already established. But this method is very difficult because Derailment is caused by multiple factors. To evaluate the derailment factor of running train that runs on the curved track, we make use of mechanism that wheel loads and lateral forces were affected by track and rolling stock parameter. In this paper, deal with a search on the parameter and derailment factor. According to results of computer simulation value of Q/P, running safety is connected with operation velocity, curve radius, cant, track irregularity, suspension stiffness and static wheel load ratio, etc.

• 한국정보통신학회논문지
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• 제13권6호
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• pp.1083-1090
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• 2009

차지상간 통합데이터전송 시스템에서 사용하는 18GHz는 다중경도페이딩의 영향이 크고, 회절이 되지 않아 전파의 도달 범위가 송신각과 수신각에 따라 크게 영향 받는다. 본 논문은 차지상간통합데이터전송 시스템에서 지하구간의 전파 특성과 지상 구간의 전파 특성을 비교하였다. 18GHz 차지상통합데이터전송 시스템에 주로 사용되는 지향성 무선안테나인 이득이 15dBi 와 10dBi인 안테나를 사용했을 경우를 가정하여 반경이 100, 200, 400인 선로에 대하여 표준적인 특성을 지상선로구간과 지하터널구간으로 나누어 비교하였다. 이때 송수신 특성은 한국철도기술연구원의 차지상간통합전송의 OFDM모뎀방식의 샘플시료의 송신 출력은 20dBm, 수신감도는 -90dBm을 사용하여 시뮬레이션하였다.

• ETRI Journal
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• 제40권1호
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• pp.39-50
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• 2018

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the "Mobile Hotspot Network" system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.