• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1415-1419
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• 2004

It is essential to evaluate harmonic characteristics of high speed train using power electronics equipment such as converter-driven motor drives, battery chargers and auxiliary power supplies. The purpose of this study is to measure and analyze harmonics characteristics of korea high speed train prototype. This paper presents result of harmonics measurement and analysis of harmonics characteristics in terms of loading, speed and operation mode.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.116-121
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• 2001

Prediction of the top(service) speeds of high-speed trains and configuration design to trainset of them has been studied using the neural network system The traction system. The traction system of high-speed trains is composed of transformers, motor blocks, and traction motors of which locations and number in the trainset formation should be determine in the early stage of train conceptural design. Components of the traction system are the heaviest parts in a train so that it gives strong influence to the top speeds of high-speed trains. Prediction of the top speeds has been performed mainly with data associated with the traction system based on the frequently used neural network system-backpropagation. The neural network has been trained with the data of the high-speed trains such as TGV, ICE, and Shinkanse. Configuration design of the trainset determines the number of trains motor cars, traction motors, weights and power of trains. Configuration results from the neural network are more accurate if neural networks is trained with data of the same type of trains will be designed.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.148-151
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• 2005

This paper proposes a high speed interface using redundant multi-valued logic for high speed communication ICs. This circuit is composed of encoding circuit that serial binary data are received and converted into parallel redundant multi-valued data, and decoding circuit that convert redundant multi-valued data to parallel binary data. Because of the multi-valued data conversion, this circuit makes it possible to achieve higher operating speeds than that of a conventional binary logic. Using this logic, a 1:4 demultiplexer (DEMUX, serial-parallel converter) IC was designed using a 0.35${\mu}m$ standard CMOS Process. Proposed demultiplexer is achieved an operating speed of 3Gb/s with a supply voltage of 3.3V and with power consumption of 48mW. Designed circuit is limited by maximum operating frequency of process. Therefore, this circuit is to achieve CMOS communication ICs with an operating speed greater than 3Gb/s in submicron process of high of operating frequency.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.221-226
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• 1999

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 50m/min using the high speed ball screw. Also, a lot of problems have happened the feed and servo drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed/accuracy control for feed/servo drive system of high speed/accuracy. In this study, we make use of high performance vertical machine center with a ball screw of large-scale-lead. Also, we'll apply the high-speed/accuracy control technology in this part of feedforward control, multi-buffering block size, etc. Using the design of the mechanical element and high-speed precision control, the basic design concept can be established.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.279-284
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• 2000

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 60m/min using the high speed ball screw. Also, a lot of problems have happened the feed drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed control for feed drive system of high speed. in this study, we make use of the feed drive system with a high lead ball screw. We'll develop the feed drive system at the speed of 60m/min. Using the design of the mechanical element and the high speed control, the basic design concept can be established. After manufacturing one-shaft feed drive system and then conducting the performance test, It'll be analyzed properties of the high speed feed drive system.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.195-197
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• 2006

The present study examined the characteristics of high speed welding thin metal sheet using single mode fiber laser of averaged maximum output power 300 W. Due to the fiber laser that has a good quality of beam can make a very small focusing beam size, thin metal sheet welding and high speed key hole welding can be peformed by high power density.

• Journal of Wind Energy
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• v.10 no.4
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• pp.20-27
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• 2019

High-speed shaft coupling in a wind power system transmits power and absorbs variations in length and spindle dislocation between the gearbox and generator. Furthermore, the coupling has an insulation function that prevents electrical corrosion caused by the flow of the generator's current into the gearbox and prevents overload resulting from sudden power failure from being transferred to the gearbox. Its design, functions, and part verification are described in the IEC61400 and GL Guidelines, which specify that the part must have a durability life of 20 years or longer under distance variation and axial misalignment between the gearbox and the generator. This study presents the design of a high-speed coupling through composite stiffness calculation, structural analysis, and comparative analysis of test and theory to identify the characteristics of high-speed coupling for a large-capacity 6 MW wind power generator. A prototype was fabricated by optimizing the manufacturing process for each part based on the design, and the reliability of the fabricated prototype was verified by evaluating the performance of the target quantitative evaluation items.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.948-949
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• 2008

In this paper, an effect on power conversion unit in next generation high-speed train by loss of contact between a contact wire and pantograph supplied electrical power to high-speed train are investigated. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that arc phenomenon by loss of contact brings out EMI. To analysis of conducted EMI source on powering mode of next generation high-speed train, it is necessary electrical modeling system between the contact wire and the pantograph according with loss of contact. Therefore analytical model of a contact wire and a pantograph is constructed to simulate the behaviour of loss of contact. The reliability of the modeling system is verified by simulation implementation on loss of contact.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.39-44
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• 1999

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 60m/min using the high speed ball screw. Also, a lot of problems have happened the feed drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed control for feed drive system of high speed. In this study, we make use of the feed drive system with a ball screw of large-scale-lead. We'll develop the feed drive system at the speed of 60m/min. Using the design of the mechanical element and the high speed control, the basic design concept can be established. After manufacturing one-shaft feed drive system and conducting the performance test, it'll be analyzed properties of the high speed feed drive system.

• Transactions on Electrical and Electronic Materials
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• v.17 no.6
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• pp.317-328
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• 2016

Over the past few decades, CMOS current comparators have been used in a wide range of applications, including analogue circuits, MVL (multiple-valued logic) circuits, and various electronic products. A current comparator is generally used in an ADC (analog-to-digital) converter of sensors and similar devices, and several techniques and approaches have been implemented to design the current comparator to improve performance. To this end, this paper presents a bibliographical survey of recently-published research on different current comparator topologies for low-power and high-speed applications. Moreover, several aspects of the CMOS current comparator are discussed regarding the design implementation, parameters, and performance comparison in terms of the power dissipation and operational speed. This review will serve as a comparative study and reference for researchers working on CMOS current comparators in low-power and high-speed applications.