• 한국안전학회지
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• 제33권2호
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• pp.145-151
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• 2018

In this study, the track-bridge interaction analysis was performed using an analytical model considering the track structure, thereby taking into account the linear conditions (R=650 m, cant variation $160{\pm}60mm$) and the dynamic characteristics of the bridge. As a result of the study, the allowable speed on the example bridge considered was calculated at 200 km/h based on vertical deflection, vertical acceleration, and irregularity in longitudinal level, but was also evaluated at 170km/h based on the coefficient of derailment, wheel load reduction, and lateral displacement of the rail head. It is considered desirable to set the speed 170km/h to the speed limit in order to secure the safety of both the bridge and the track. It is judged that there will be no problems with ensuring rail protection and train stability in the speed band.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1033-1040
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• 2004

Utilizing of the geotextile container shows several advantages such as standardized construction, factory manufactured products, the control of quality, workability. and economical point of view. Recently this technique can be applied to rehabilitate the loss of rail roadbed due to the heavy rainfall. In this study, a large-scale laboratory test were conducted with simulation of static performance on the geotextile container reinforced rail roadbed. Based on the laboratory test results, the vertical pressure distribution with respect to the depth, and settlement of rail roadbed were measured and compared test results between geotextile container reinforced case and unrein forced case. Thus, the effectiveness of reinforcement was evaluated in terms of its performance and stability.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.159-166
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• 1999

In this paper, running performance analyses of an articulated light rail vehicle are carried out using VAMPIRE software package. The stability analysis to determine the critical speed and the safety analysis such as derailment coefficients, lateral forces of wheels and reduction of wheel load are carried for the track conditions of straight, transition and curving range to the operating velocity of 40km/h. Also, ride quality is analyzed. As the results of analysis, the safety of light rail vehicle satisfied with the limit values and the ride quality for tare and full load condition was shown to the "not uncomfortable" level in ISO 2631-1 (1997) criteria.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.299-302
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• 2008

The behavior of continuous welded rail tracks is directly affected by the following various parameters: rail size; track curvature; neutral temperature; misalignment; and ballast resistance. Most of these parameters are having the nature of random variables. Therefore, uncertainties exist in the buckling safety assessments. The evaluation of the buckling safety and the maintenance strategy based on the deterministic analysis are very inefficient since the value of deterministic parameters are selected in worst track condition. In this study, the probabilistic approach method were investigated considering the probabilistic distribution of major parameters such as the neutral temperature of rail and the ballast resistance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.10-16
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• 2008

In order to improve stability of rail and ride comfort, railway bridges should be maintained a integrity. However, it is necessary to plan various reinforcements and improvements because of a long term used and external effects. In this paper, the improvement plan which is reflected by investigation for reinforcement and improvement is introduced. The constituents of the structures are defined in order to optimize the improvement plane, and the analysis for relationships between the constituents are performed by several evaluation. Finally, the improvement plan is applied to a structure using impact factors for the external effects in order to obtain the improvements reasonably.

• 한국철도학회논문집
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• 제7권4호
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• pp.367-373
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• 2004

The investigation of running stability of the train for curved track is necessary in view of preventing the train from derailment caused by unbalanced forces transferred from the wheel and guaranteeing moderate level of running safety in curve sections. This paper carried out an analysis of running stability of tilting trains in conventional line which the test operation of tilting trains under development are scheduled. For this purpose, the wheel load and lateral pressure to the rail are evaluated. The criteria for the calculated wheel load and derailment coefficient are compared to the design criteria for running stability. It is founded that the running stability of tilting trains for curved track is guaranteed to have sufficient safety and the train speed in curve is governed by the geometric layout of track rather than the criteria for running stability.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1300-1309
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• 2010

In the railway bridges, steel plate girder types are preferred due the high stability. Nevertheless, it has been pointed out that this type of bridge has problems such as, structural damages in the rail and girder seat, noise problem due to impact at the rail joint and excessive vibration. This vibration and/or deflection are mainly because insufficient stiffness of steel plate type of bridge. To resolve these problems, PC-Slab composite plate girder type which has simple process and economic cost, is proposed in this study. The static and dynamic experiment is performed by using the production of actual sized PC-Slab and abandoned steel plate girder. The object of this experiment is to verify the fact that girder stiffness increase and structural safety. The result of the experiment is used to analyze the effect of performance improvement of PC composite plate girder type. Using this method, economic rail maintainers, girder stiffness increase, and also speed/ride improvement even for existing rail could be expected by dynamic performance improvement. Additionally noise due to impact, deflection and vibration caused from long rails can be reduced.

• Transactions on Electrical and Electronic Materials
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• 제2권4호
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• pp.1-6
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• 2001

In this paper, a 1.5 V high-gain high-frequency CMOS complementary operational amplifier is presented. The input stage of op-amp is designed for supporting the constant transconductance on the Input stage by consisting of the parallel-connected rail-to-rail complementary differential pairs. And consisting of the class-AB rail-to-rail output stage using the concept of elementary shunt stage and the grounded-gate cascode compensation technique for improving the low PSRR which was a disadvantage in the general CMOS complementary input stage, the load dependence of open loop gain and the stability of op- amp on the output load are improved, and the high-gain high-frequency operation can be achieved. The designed op-amp operates perfectly on the complementary mode with the 180° phase conversion for a 1.5 V supply voltage, and shows the DC open loop gain of 84 dB, the phase margin of 65°, and the unity gain frequency of 20 MHz. In addition, the amplifier shows the 0.1 % settling time of .179 ㎲ for the positive step and 0.154 ㎲ for the negative step on the 100 mV small-signal step, respectively, and shows the total power dissipation of 8.93 mW.

• 한국컴퓨터정보학회논문지
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• 제23권11호
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• pp.193-201
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• 2018

In this paper, we extracted relevant patent data and conducted statistical analysis to understand the technical development trend related to Wireless Power Transfer (WPT) for Light Rail Transit (LRT). Recently, with the development of WPT technologies, the Light Rail Transit (LRT) industry is concentrating on applying WPT to the power supply system of trains because of their advantages compared wired counterpart, such as low maintenance cost and high stability. This technology is divided into three areas: wireless feeding and collecting technology, high-frequency power converter technology and orbital and infrastructure technology. From each specific area, key words in patent document were extracted by TF-IDF method and analyzed by social network. In the keyword network, core word of each specific technology were extracted according to their degree centrality. Then, the multi-word phrases were also built to represent the concept of core technologies. Finally, based on the analysis results, the development strategies for each specifics technical area of WPT in LRT filed will be provided.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.119-125
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• 2016

본 논문에서는 기존 휠-레일 고속열차에 자기부상열차의 추진방법을 적용한 하이브리드 방식의 고속열차의 주행 동특성에 대해서 연구하였다. 초전도 선형동기전동기를 추진 동력으로 하는 휠-레일 방식의 고속열차는 강력한 추진력을 지니면서도 자기부상열차에 비해 기존 선로와의 호환성 및 경제성 측면에서 유리할 것으로 예상된다. 본 논문에서는 초전도 선형동기전동기를 기존의 휠-레일 고속철도에 적용하는 두 가지 방안에 대해서, 초전도 선형동기전동기 추진이 휠-레일 고속열차의 동특성에 미치는 영향을 살펴보기 위하여 초전도 선형동기전동기의 회전자와 고정자의 상호 작용을 검토하고 이를 포함한 차량의 동특성 모델을 구축하였다. 구축된 모델을 이용한 시뮬레이션을 통해 초전도 선형동기전동기의 회전자와 고정자의 상호 작용이 주행 중 고속 안정성, 승차감 및 가이드웨이 불규칙도에 미는 영향을 분석하였다.