• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.125-132
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• 2011

The dynamic characteristics of valve train are responsible for the dynamic performances of engine. We derived the equation of motion for 6 degrees of freedom model of the valve train. Computer model is also developed with flexible multibody model considering contact between components. The simulation results with these two models are compared with experimental results. We investigated the effect of the two spring models, TSDA (Translational Spring Damper Actuator) element and flexible body model, on the valve behavior and spring force. It is found that the dynamic behavior of the two models are not very different at normal operational velocity of the engine. By modeling contact between cam and tappet, the stress distributions of the cam were found. Using stress distribution obtained, contact width and contact stresses of the cam surface were calculated with Hertz contact theory.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.255-261
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• 1998

The train automatic operation control system is an on-board train control system that is widely adopted in modern rapid transit systems. The control system consists of TCMS(Train Control and Monitoring System), ATC(Automatic Train Control), ATO(Automatic Train Operation) and TWC(Train to wayside communication) in the train and wayside facilities. The functions of the system is to regulate train riding comfort, to service limited speed and smoothness during start, acceleration, constant speed travel, and fixed point parking under the corresponding commands. The paper describes the simulation model of the train automatic operation control of subway system, configuration of simulator hardware and software and operational algorithms.

• Journal of Korean Society for Quality Management
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• v.33 no.3
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• pp.71-90
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• 2005

New high-speed rail service, the Korea Train Express(KTX), has been beginning service in Korea. We measured the service quality of the Korea Train Express and comparatively analyzed the service quality of domestic flight and express buses which are means of long distance transportation. Furthermore, by using the Kano model, the perception level of the service of customers is not only segmented in groups but also switching barriers are derived. As a result, the customers by group have a difference in the level of their perception. While in both high-speed bullet train service and flights dimensions significantly affect the customer satisfaction and retention excluding a responsiveness dimension, in the Train Express four dimensions(Reliability, Responsiveness, Assurance, Tangibles) with the exception of Empathy which significantly affect the customer satisfaction and retention.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.40-47
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• 2002

In this study, and analytical method for ride sensitivity analysis of a train with non-linear suspension elements are proposed. Non-linear characteristics of springs and dampers for primary and secondary suspensions of a train are parameterized using polynomial interpolation. Vertical dynamic model of a three-body train running on straight rail with the predetermined roughness expressed in terms of spectral density function is set up and its equations of motion for ride analysis are derived. Using the direct differentiation method, sensitivity equations of the vertical dynamic model with respect to design parameters associated with non-linearity of suspensions are obtained. Based on the sensitivity analysis, improvement of ride is achieved by varying appropriate suspension parameters.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.2
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• pp.53-63
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• 1993

A numerical modeling technique is proposed for computer simulations of high speed valve train dynamic terms in the valve spring reaction forces are calculated using linear vibration theory for given kinematic valve motions. Because the spring dynamics are analyzed before the time stepping integration, spring surge phenomena can be included without using additional computer time. In addition to that, steady state response of the valve dynamics can be obtained by just one cycle simulation. Consequently, valve train dynamics can be simulated very quickly without noticeable errors in accuracy. The experimental result prove the computer model developed here is accurate and also computationally efficient. The model is especially useful for cam profile optimizations.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.472-476
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• 2003

A real train load fluctuates along the track because of complicated movements(Bouncing, Rolling, Pitching and Yawing) and rail conditions. This research has for its object in development of a numerical train load model including fluctuation characteristics of lateral forces. It is based on Klingel movement theory of a wheelset on straight track. it presents a propriety of application by comparison between a 3D-Numerical analysis result using this train load model and a measured data. And this paper presents further study subject to improve a method about the train load modeling.

• Journal of the Korean Society for Railway
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• v.4 no.2
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• pp.47-54
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• 2001

Railway companies have been faced with many changes in the railway environment. To cope immediately with the influence of environment and to improve productivity, an efficient train operation system and related core technologies must be introduced. The railway system is composed of large scale infrastructures and high-cost trains. Simulation method is one of core technologies and also efficient tool for planning and analyzing these kinds of complex system. In this research, we review basic simulation programming models and present a modeling for the elements of railway system such as rail-line infrastructure, train, time table and operational route. Additionally, some considerations on the development of multi-train traffic simulator for KyongBu-line are discussed.

• Journal of Industrial Technology
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• v.18
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• pp.225-232
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• 1998

Train crashes involve complex interaction between deformable bodies in multiple collisions. The purpose of this study is to suggest the effective analytical procedure using finite element model for the crashworthiness of motorized trailer of high speed train. Various types of crash events are investigated and the conditions for numerical simulation are defined. Finally korean high speed train which consists of aluminum members can be analyzed and designed by the numerical simulation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.12
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• pp.624-629
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• 2002

This paper presents the first Simulation model using EMTDC program to analyze the electrified train voltage distribution characteristics in ac auto-transformer 1110 railroads. In general, all of the electrified train supply system has the characteristics that the train supply line is a naturally non-symmetrical and unbalanced system. Also, it is needed to model the Scott transformer which invert the balanced 3-phase quantity into 2-phase. Therefore, the general simulation methodology using previous simplified equivalent circuit or RMS based program can't obtain the accurate results to reflect the real-time operation because these methodology is basically assumed on completely 3-phase balanced system. To overcome these defects, in this paper, the EMTDC simulation model to analysis the completely electrified railroad system with Scott transformer and AC auto-transformer is presented. Also, the correctness of EMTDC modeling is confirmed by the old basic concepts and we think that this EMTDC model has the future powerful capability for application of railroad system analysis.

• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.253-259
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• 2002

This paper presents the first simulation model using EMTDC program to analyze the electrified train voltage distribution characteristics in ac auto-transformer fed railroads. In general, all of the electrified train supply system has the characteristics that the train supply line is a naturally non-symmetrical and unbalanced system. Also, it is needed to model the Scott transformer which invert the balanced 3-phase quantity into 2-phase. Therefore, the general simulation methodology using previous simplified equivalent circuit or RMS based program can't obtain the accurate results to reflect the real-time operation because these methodology is basically assumed on completely 3-phase balanced system. To overcome these defects, in this paper, the EMTDC simulation model to analysis the completely electrified railroad system with Scott transformer and AC auto-transformer is presented. Also, the correctness of EMTDC modeling is confirmed by the old basic concepts and we think that this EMTDC model has the future powerful capability for application of railroad system analysis.