• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.163-166
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• 1997

In order to shorten head-way time on existing railway lines without any change of signal block length between stations, it is a realistic optional way to change the control method of train signal, i.e. to modernize the cab signal using transponder. A new signalling system of operation pattern control technique is suggested as new model to increase the railway traffic efficiency. Through the computer simulation of this model, the train head-way time by the fixed signalling system and the new pattern control system is analyzed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.1
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• pp.52-57
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• 2009

One of the error sources for microwave ranging is the instability of the oscillator that drives the microwave signals. Dual one-way ranging (DOWR) minimizes the oscillator effect by combining two one-way carrier phase signals from two transmitter/receiver instrument. The DOWR is first implemented in the GRACE (Gravity Recovery and Climate Experiment) satellites. Direct evaluation of the DOWR is not possible due to its extremely high accuracy. The flight performance of the GRACE DOWR is analyzed by applying several indirect methods. Comparison with the design noise level is discussed.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.88-92
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• 1999

As a part of work to simulate electromagnetic environments for Hardware-In-the-Loop(HIL) simulation, the dynamic trajectory is modeled by the Way-points method and the Event-driven method for the aerial and the naval targets. The simulated results show that the Way-points method and the Event-driven method are appropriate to simulate a low speed and a high speed target respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.950-953
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• 2005

This study presents development of a multi-way high speed pipe cutting machine to improve production rate of pipe cut pans. In this paper, structural and modal analysis for the developed machine is carried out to check safety of the machine design. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. The machine is modeled by placing proper shell and solid finite elements. The final results of analysis are applied to the design of multi-way high speed pipe cutting machine and the machine is successfully developed.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.535-543
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• 2014

In this paper, I proposed a way of improving computer education in elementary, middle and high schools. I firstly analyzed the importance of computer education by researching an index of a national economic condition, People's IT use frequency and the demand for computer education by students and parents. Secondly, I researched the condition of computer education in elementary, middle and high schools. Finally, I analyzed problems of current computer education and proposed three way of improving computer education in elementary, middle and high schools.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1008-1013
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• 2003

This paper concerns the structural characteristic analysis and evaluation on the hydrostatic guide way and feeding system of a high precision centerless grinder for machining ferrules. In order to realize the required accuracy of ferrules with sub-micron order, the axial stiffness and motion accuracy of feeding system have to become higher level than those of existing centerless grinders. Under these points of view, the physical prototype of feeding system consisted of steel bed, hydrostatic guide way and ballscrew feeding mechanism is designed and manufactured for trial. Experimental results show that the axial and vertical stiffnesses of the physical prototype are very low as compared with those design values. In this paper, to reveal the cause of these stiffness difference, the structural deformations on the virtual prototype of feeding system are analyzed based on the finite element method under experimental conditions. The simulated results illustrate that the deformation of front ballscrew support-bearing bracket is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.896-903
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• 2004

This paper proposes the structural characteristic analysis and evaluation on the hydrostatic guide way and feeding system of a high-precision centerless grinder for machining ferrules. In order to realize the required accuracy of ferrules with sub-micron order, the axial stiffness and motion accuracy of feeding system have to become higher level than those of existing centerless grinders. Under these points of view, the physical prototype of feeding system composed of steel bed, hydrostatic guide way and ballscrew feeding mechanism is designed and manufactured for trial. Experimental results show that the axial and vertical stiffnesses of the physical prototype are very low as compared with those design values. In this paper, to reveal the cause of these stiffness difference, the structural deformations on the virtual prototype of feeding system are analyzed based on the finite element method under experimental conditions. The simulated results illustrate that the deformation of front ballscrew support-bearing bracket is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.94-99
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• 2012

Due to economic growth, the number of cars has grown rapidly and consequently traffic accidents have grown in direct ratio. This reminds us that braking device of a vehicle is an important factor to prevent traffic accidents. Aim these researches to speed and lighten the braking system of vehicles, to lengthen its durability and to shorten the stopping distance. However, it is still difficult to analyze quantitatively and clearly the reason and solution for abnormal wear of disc and pad or judder in flywheel mode. Therefore this study was carried out to presume for mutual relation of analysis condition to get the optimum temperature by two-way layout. The results shown that coefficient of determination has a fine reliability over 92.57% and temperature is made by two-way layout.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.393-396
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• 1997

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut and feed rate are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.88-96
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• 2002

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.