• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.645-651
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• 2009

Previous studies have introduced the technique of spinous process osteotomy to decompress spinal stenosis, a procedure which aims to afford excellent visualization while minimizing destruction of tissues not directly involved in the pathologic process. However, biomechanically it has not been investigated whether the sacrifice of posterior spinous process might have potential risk of spinal instability or not, even though supra-spinous and inter-spinous ligaments are preserved. Therefore the aim of this study is to evaluate the biomechanical properties after spinous process osteotomy, using finite element analysis. The model of spinous process osteotomy exhibited no significant increase in disc stress or change in segmental range of motion. It is due to the fact that the instability of lumbar spine has been maintained by the two-types of ligaments compared with the prior surgical technique. Therefore, according to the finite element result on this study, this osotetomy was considered to be a clinically safe surgical procedure and could not cause the instability of the lumbar spine.

• 대한예방의학회:학술대회논문집
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• 1999.10a
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• pp.244-245
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• 1999

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.842-843
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• 2011

Winding methods of the interior permanent magnet synchronous motor for vehicle traction have two kinds. They are concentrated winding and distributed winding. They have merits and demerits and influence motor performance. Therefore, this paper present designs that concentrated winding and distributed winding motor what they have same capacity. And each motor characteristic was analyzed by finite element analysis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.670_671
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• 2009

This paper presents a optimum design process for static torque characteristics of the Claw-Poles PM Stepping Motor(CPSM). Since the shape of CPSM changes along with axial direction, CPSM should only be analyzed by 3D-FEM. But 3D-FEM needs too much computation time and computer resources. Therefore, it is essential to reduce the number of 3D-FEM analysis models. In this paper, two design factors which affect the static torque characteristics of CPSM were selected. Optimum design process was able to make progress by using Pattern Search Algorithm and 3D-FEM. Finally, optimized model was compared with a conventional model.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.71-72
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• 2008

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.472-473
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• 2006

배전계통 원격감시제어 기능을 수행하는 배전자동화 주장치 운영S/W는 정확한 개폐기 제어를 위해서 사용자에게 정보를 쉽고 빠르고 명확하게 전달해야 함을 기본으로 하고 있다 1998년 처음 도입된 소규모 배전자동화 시스템은 해가 거듭될수록 현장의 다양한 요구가 발생하게 되었고 이를 해소하고자 S/W 성능개선을 추진하게 되었다. 본 논문에서는 S/W개선내용을 GUI변경을 통한 편의성향상과 중요현황 및 통계화면 추가로 조작의 신뢰성향상, 조작 전 재확인절차 추가 및 데이터 손실방지 등의 안정성을 향상시켜 신속한 고장파악 및 정확한 고장복구로 안정된 전력공급에 기여할 수 있을 것으로 사료된다.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.43-48
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• 2010

The performance of photovoltaic systems could be affected by various factors including installing conditions of modules, and their own efficiencies of solar cells and inverters. The installing conditions of a photovoltaic system including array types, tilting angles, azimuth, locations, quantities of sunshine, optimum angles of inclination and separated distance are analyzed using the SolarPro & Minitep SW simulation program, inorder to set up the installing conditions for improving system performance. The result from the simulation of the 500kWp PV system of Kochang with optimal installing conditions compared with normal conditions shows that the capacity factor has been increased from 11.02% to 12.06%.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.132-135
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• 2010

Thermal properties of layered metal chalcogenides such as $WT_2$ (T=S,Se) with two-dimensionally disordered structure were evaluated. Thermal conductivity shows a marked decrease after exfoliation and subsequent restacking because of random stacking of two-dimensional crystalline sheet, which circumvents thermal conduction pathways along longitudinal direction in anisotropic materials.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1127-1128
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• 2008

In this paper, we propose a control method to improve control performance for a Quad-rotor Unmanned Aerial Vehicle's stabilization. The proposed method is the Fuzzy+I control that contains a fuzzy controller which processes signals from the error and the change of error, and generates the control signal by summing up fuzzy output signal and integral signal. We simulated and experimented on the fuzzy+I control method by implementing Quad-rotor UAV that is able to hovering, for the purpose of verifying the effectiveness of the proposed fuzzy+I control method in comparison with general PID control, and we found out that fuzzy+I controller improved control performance of the system.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1409-1415
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• 2010

A linear induction motor have advantages for reducing mechanical frictions and noises because it has thrust force by induced torque instead of friction force between rail and wheels. An it has additional advantage for reducing volume of bogie frame for light rail transit. The small volume causes the cost of construction down. Recently, researches of linear induction motor for thrust force of the light rail transit have been actively studied. For the rail transit, vehicle is running as follow accelerating and constant speed, finally decelerating speed passing local stops between stations. The light rail transit have only these three patterns of operating. Thus, design of that has different design specifications from others. In this paper, the linear induction motor for the light rail transit was designed considering the goal speed, accelerating time, and accelerating distance for approaching the goal speed. The designed motor was proved that it could meet the requirement of accelerating performance by2-dimensional finite element method and mechanical dynamics equation.