• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.174-183
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• 2005

A train driving requires to n the fixed distance within given time, and it is desirable to consume low energy if necessary. Reducing energy consumption depends on the train operation modes by either manual or automatic operation. In this article, an operation to reduce energy consumption by changing modes of train operation by a driver without changing the train operation requirement is investigated. The powering model, braking model and consumed energy calculation model are developed, then simulated by using a Matlab software. The accuracy of the train dynamic model established by the simulations is verified by comparing with the real experimental data. Several simulations by various operations in the real track are executed, then the desirable pattern of train driving is found.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.233-242
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• 2014

A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.46-53
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• 2002

The brake system of a high speed train has a crucial role for the safety of the train. To develop a safe brake system of the high speed train, it is necessary to understand the braking principle and phenomena of the total brake system and its subsystems. In this paper, we have suggested a mathematical model which includes car dynamics, interactions between cars, adhesive forces, brake blending algorithm, and the dynamics of each brake devices. Also, we have proposed a ready-time compensation algorithm of eddy-current brake system and a brake control logic on electric-pneumatic blending. A simulation study has shown the proposed models and algorithms are effective on the braking of the train.

• Journal for History of Mathematics
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• v.36 no.6
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• pp.105-113
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• 2023

We will suggest a train model to explain the weekly periodic character of Covid19 in South Korea on the first half of 2022, the period of the Omicron variant outbreak. In the model, the daily new infected individuals board a train, divided into 4 compartments. The train moves at night by the length of one compartment. Then the infected are quarantined during the daytime after their compartment reaches the quarantine area. Then it remains empty on the 5-th night after boarding. The parameters of the model are fitted with the daily measured quarantine populations and generate the simulated quarantine populations that hit the real weekly and global peaks.

• Wind and Structures
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• v.20 no.4
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• pp.509-525
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• 2015

A three-dimensional aerodynamic model and a vehicle dynamics model are established to investigate the effect of noise barrier on the dynamic performance of a high-speed train running on an embankment in crosswind in this paper. Based on the developed model, flow structures around the train with and without noise barrier are compared. Effect of the noise barrier height on the train dynamic performance is studied. Then, comparisons between the dynamic performance indexes of the train running on the windward track and on the leeward track are made. The calculated results show that the noise barrier has significant effects on the structure of the flow field around the train in crosswind and thus on the dynamic performance of the high-speed train. The dynamic performance of the train on the windward track is better than that on the leeward track. In addition, various heights of the noise barrier will have different effects on the train dynamic performance. The dynamic performance indexes keep decreasing with the increase of the noise barrier height before the height reaches a certain value, while these indexes have an inverse trend when the height is above this value. These results suggest that optimization on the noise barrier height is possible and demonstrate that the designed noise barrier height of the existing China Railway High-speed line analysed in this article is reasonable from the view point of the flow field structure and train dynamic performance although the noise barrier is always designed based on the noise-related standard.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.126-131
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• 2003

The acceptance test of KTX has been performed in Korea. During the test, lateral vibration of carbody over the accepted value called sway was found. KTX has 20 car trainset formation whose trailer cars are linked by articulate bogies. So this study is performed to see the effects of long trainset formation on vehicle dynamics and the train stability by 20 car vehicle model. Firstly the reliable vehicle model which shows well the tendencies appeared in the tests on the high speed test line is required to find the cause of lateral vibration and the countermeasure. Vehicle model was made .for the. analysis with VAMPIRE. The analysis results show that secondary air spring lateral stiffness is the most significant parameter to cause carbody lateral vibration. Mode analysis results show that the least damped mode shape is similar to the vibration pattern shown in the tests that the amplitude of the motion increases along the train set and decreases in the tail part. For the case of short train formation with 7 or 10cars, sway does not happen. But in the case of longer train formation with 16 or 20 cars, sway was found.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.116-120
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• 2011

For the train positioning system currently applied in high-speed MAGLEV train systems, it is classified into absolute positioning systems which discontinuously detect train positions, and relative positioning systems which continuously detect train positions. In this paper we analyze the configuration model and the numerical model of the absolute positioning system applied in TRANSRAPID which is a representative high-speed MAGLEV train, and design the two configuration models specific to the recognition structures of absolute positioning systems. We also verify the compatibility of the design models of absolute positioning system through simulation using MATLAB and propose the optimal configuration model of absolute positioning systems for high-speed MAGLEV train system.

• Journal of the Korean Society for Railway
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• v.8 no.5
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• pp.454-459
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• 2005

In this study, the relationship between tie shape and underbody train gust of high-speed train is numerically investigated. To this end, complex train underbody/railroad model is replaced by simple plate/tie model. And it is tried to find a most important parameter for reduction of underbody train gust through the Taguchi method and orthogonal array. As a result, it is verified that the height of tie is most sensitive to the underbody train gust because of the cavity effect between ties. When the width and distance between ties are decreased, underbody train gust is also reduced. Consequently, the heighter is examined which can give the similar effect of higher tie without replacement of tie. The 5cm heighter can reduce underbody train gust about $73\%$, which value is only $7\%$ less than the higher tie.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.72-79
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• 2001

In this paper we present a nonlinear programming model for the solution of the train seat capacity distribution problem (TSCDP) with a numerical example. The TSCDP model finds the optimal capacity distribution methods which minimize the sum of the differences between the demands and the seat capacities. Also the TSCDP provides the information on the degree of the discrepancy between the demand and the seat capacities. One can use the TSCDP model as a tool for planning train seat capacity planning.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.116-122
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• 2000

This paper presents a simulation method with constant power model for the train load. In power system simulation loads could be modeled as a constant power, constant current, constant Impedance or a function of voltage and frequency. At this time, however, representing a train load as the function is difficult because of the lack of data. Therefore as a first step, simulation method with a constant power model fer a train is studied, and the test result is compared with the simulation result using the constant Impedance model.