• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.166-173
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• 2006

This paper investigated strength of a bogie frame for Korean tilting train that is being developed in KRRI. In this study, static load tests based on Japanese Industrial Standard (JIS) were performed. In order to simulate vertical and lateral components generated by tilting link mechanism, four hydraulic actuators were used. The eight load cases such as vertical, lateral, traction, braking and driving gear loads were applied for evaluation of the strength of bogie frame. The stresses measured at the stress concentration points were assessed using Goodman diagram. From the experimental results, structural safety of the bogie frame could be ensured.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.3
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• pp.127-133
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• 2005

Korean multi-propulsion system consists of a synchronous alternator driven by a gas turbine driving synchronous alternator coupled to a rectifier - DC link - DC/DC converter and traction system based on modification of the G7 high-speed train. The simulation modules include turbine engine system, alternator, rectifier, DC/DC converter and power management module. Simulation for the multi-propulsion system such as a modular is presented in order to confirm the system stability for loads with uncertain input impedances and control loop speeds. This paper deals with various simulation modules with a specific control loop to help the development of the real lame-scaled system.

• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.222-230
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• 2002

The rotating bogie frame is used in the bogie for a Light Rail Train under development in Korea. In development of the bogie, the structural strength and fatigue characteristics of the rotating bogie frame have been evaluated under the predefined load cases according to the Korean standards for a urban EMU. No part of the rotating bogie frame was subjected to stress beyond the fatigue endurance limits of the material used when grinding the welding of the lower plate link. It is concluded that the rotating bogie frame is safe in view of its static and fatigure strength.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.92-99
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• 2013

The ratio of mobility handicapped was 12,110,000 in late 2009 about 24.4% of total population. The number of handicapped population is increasing continuously due to traffic accidents and industrial disasters. Therefore, the purpose of this research is to suggest a design for passengers on wheelchairs to get into and off to raise handicapped or elderly people's right of mobility. The scope of this research is mobility handicapped especially wheelchair passengers who use vans, small buses, and trains. The ramp design of vans is module form. The ramp is moved with screw jack and guides are installed on each side to increase stability. Moreover, a bridge was installed for smooth getting in and off of the van. The ramp design for small bus is lowed by 200m in order not to have obstacle such as speed bump when getting in or off. In order to reduce vulnerable environment and administration, air slide cylinder was chosen. Lastly, for the ramp design of train, the principle of link was used that the simpler structure made the weight lighter and installation in the train became easier. If we look at the conjugation condition of heterogeneous materials to produce a ramp, proper welding condition for cold steel plate and stainless plate is 3kW output and 3-5m/min of welding speed using laser beam seems proper.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.121-127
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• 2023

A 500 km/h linear motor high speed terrestrial transportation service is planned to launch 2027 in Japan. In order to support 5G service in the train, the Sub-carrier spacing frequency of 30 kHz is planned to be used instead of common 15 kHz sub-carrier spacing to mitigate Doppler effect in such high-speed transportation. In addition, to increase the cell size of 5G mobile system, plural Base Station antenna will transmit the identical Down Link (DL) signal to form the expanded cell size along the train rail. In this situation, forward and backward antenna signals will be Doppler shifted by reverse direction respectively and the receiver in the train might suffer to estimate accurate Channel Transfer Function (CTF) for its demodulation. In this paper, Delay and Doppler Profiler (DDP) based Channel Estimator is proposed and it is successfully implemented in signal processing simulation system. Then the simulated performances are compared with the conventional Time domain linear interpolated estimator. According to the simulation results, QPSK modulation can be used even under severe channel condition such as 500 km/h, 2 path reverse Doppler Shift condition, although QPSK modulation can be used less than 200 km/h with conventional Channel estimator.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.387-389
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• 2001

The railway signaling systems are computerized vital equipments for safety guarantee of train running. And also it is important to prepare the reliable communication link between signalling equipments. In this paper the review of network technology for railway signalling is presented and reliable network technology for network is represented. And also the direction for our further study on these is discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.144-148
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• 1989

We solve the inverse kinematics problems in robotics by employing a neural network. In the practical situation. it is not easy to obtain the exact inverse kinematics solution, since there are many unforeseen errors such as the shift of a robot base the link's bending, et c. Hence difficulties follow in the trajectory planning. With the neural network, it is possible to train the robot motion so that the robot follows the desired trajectory without errors even under the situation where the unexpected errors are involved. In this work, Back-Propagation rule is used as a learning method.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.230-235
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• 1992

We propose a method of generating data to train a neural network controller. The data can be prepared directly by an iterative learning technique which repeatedly adjusts the control input to improve the tracking quality of the desired trajectory. Instead of storing control input data in memory as in iterative learning control, the neural network stores the mapping between the control input and the desired output. We apply this concept to the trajectory control of a two link robot manipulator with a feedforward neural network controller and a feedback linear controller. Simulation results show good generalization of the neural network controller.

• ETRI Journal
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• v.32 no.1
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• pp.160-162
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• 2010

For the acoustic models of embedded speech recognition systems, hidden Markov models (HMMs) are usually quantized and the original full space distributions are represented by combinations of a few quantized distribution prototypes. We propose a maximum likelihood objective function to train the quantized distribution prototypes. The experimental results show that the new training algorithm and the link structure adaptation scheme for the quantized HMMs reduce the word recognition error rate by 20.0%.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.179-186
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• 2007

KTX control systems mutually control OBCS, ATC, MBU, TECA, MDT, ABU, HVAC, TRAE, PID and FDTR, KTX OBCS as master, and controls other sub-control devices as slave, using various serial lines. In order to analyze physical structure of various serial link lines and mutual data transmission structure, serial line analyzer is used in many ways. To use serial line analyzer, prior and professional technics about High Speed Train and experience of using device are necessary. In spite of difficult situation of space and environment where we work for maintenance of High Speed Train, in presenting basic structure about physical connection method aquired by sub-device serial line data collection and about communication data analysis, I hope that this research will be helpful for the person who work for similar area. Also, I hope that this research will help diagnostic work of High Speed Train, which is necessary for test run of independently developed High Speed Train.