• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.767-769
• /
• 2004

The linear motor is widely used to generate linear motion. In this paper, the iron loss analysis of the linear motor is performed by using ANSYS, a commercial FEA tool and iron loss curves obtained by an Epsteiin test apparatus. For the validation of the iron loss analysis result, the experiment measuring the iron loss of the linear motor is peformed and this result is compared with iron loss analysis result.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.343-343
• /
• 2006

집적회로기판의 소형화 추세에 따라 커패시터, 인덕터, 저항과 같은 수동소자를 PCB 기판내부에 임베딩하는 연구가 국내외에서 활발하게 진행되고 있다. 본 논문에서는 polymer-metal-ceramic의 3상 복합체 구조를 가지는 임베디드 커패시터에서 Bimodal PZT분말에 따른 유전 특성에 대하여 고찰하였다. 매트릭스를 형성하는 고분자 재료로는 PMMA(polymethyl methacrylate)를 사용하였으며, 충분히 혼합된 분말을 고온에서 프레싱하여 시편을 제조하였다. 유전특성은 임피던스분석기 및 LCZ 미터를 이용하여 측정하였으며, 실험결과는 혼합법칙과 Percolation 이론을 이용하여 해석하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1996.04b
• /
• pp.133-141
• /
• 1996

The rolling piston type rotary compressor has become one of the most successful types because of its compactness and high-speed operation. The analysis described here is part of a research program directed toward maximising these advantages in refrigerant compressors. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressors. Therefore, theoretical investigation of the lubrication characteristics of rotary compressor for refrigeration & air-conditioning system is studied. And the Newton-Raphson method is used for the EHI. analysis between vane and rolling piston in the rotary compressor. The results show that the rotational speed of shaft and the discharge pressure have an important effect upon the friction force and the energy loss between vane and rolling piston. This results give important basic data for the further lubrication analysis and design of the rotary compressor.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.3
• /
• pp.35-41
• /
• 2003

The multihole blanking of thin sheet metal using progressive die set is an important process on production of precision electronic machine parts such as IC leadframe. In this paper, in order to investigate the influence of blanking order on the final lead profile and deformed configuration, simulation technique for progressive blanking process is proposed and analyzed by LS-DYNA. The results of FE-simulations are in good agreement with the experimental results. Consequently, from the results of FE-analysis based on the procedure proposed in this paper, it is possible to predict the deformation of lead and to manufacture high precision leadframes in progressive blanking process and these results might be used as a guideline to develop layout design system in multihole blanking process.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.3 s.96
• /
• pp.25-29
• /
• 1999

The lead frame manufactured by press stamping process, is an important part of semiconductor. The recent technical trend of semiconductor, chip sized and high performance package technology, requires the lead frame to be of more multi-leads and of fine ILP (Inner Lead Pitch). As the ILP is getting finer, its corresponding punch of the stamping die is getting narrower. The punch narrower than its stamping limit has been broken due to local buckling. This paper analyzed the phenomena of punch breakdown. Moreover, the punch design was modified to increase the critical limit of buckling force. This paper, also, suggested new design rules of the punch, which asks the modification of its lead frame design that has to be considered in the stage of semiconductor package design. The new design rules of lead frame design yields a good reliability of semiconductor package as well as a good quality of lead frame.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.5
• /
• pp.106-113
• /
• 2004

The eddy current brake system is a non-contact brake based on the mutual relation between the rail and the frame. Consequently, the accuracy is required in estimating the stress concentration and the deformation of the eddy current brake system. In this paper, the static analysis considering the gravity and the suction force for the deformation and the stress concentration of the main frame of the initially designed eddy current brake system was carried out. The shape of the I-type beam obtained from the optimization was analyzed and compared with the initial model. Also, the initial model was modified based on the optimization model and the result was verified to have the acceptable improvement.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.1
• /
• pp.127-138
• /
• 1994

The application of fault tree technique to the analysis of compressor failure is considered. The techniques involve the decomposition of the system into a form of fault tree where certain basic events lead to a specified top event which signifies the total failure of the system. In this paper, fault trees are made by using fault train of screw type air compressor failure. The fault trees are used to obtain minimal cut sets from the modes of system failure and, hence the system failure rate for the top event can be calculated. The method of constructing fault trees and the subsequent estimation of reliability of the system is illustrated through compressor failure. It is proved that FTA is efficient to investigate the compressor failure modes and diagnose system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.10a
• /
• pp.82-87
• /
• 1997

Large dynamic loads act on the rotor in rotary compressors. There are unbalance forces due to eccentric parts and gas forces induced by the pressure difference between compression and suction gases. Rotor-journal bearing system is nonlinear since the stiffness and damping coefficients of the lubricating oil film are not constant in the bearings. The system is considered as a coupled problem of flexible rotor and the journal bearings. Bearing reaction force is calculated from pressure of oil film using Reynolds equations in journal bearings. Pressure distribution in journal bearing is analyzed by finite difference method. The dynamic response of rotor and bearing characteristic are discussed when rotary compressor has a relative misalignment.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2004.05a
• /
• pp.1633-1636
• /
• 2004

최근 유비쿼터스 게임의 성장과 더불어 이기종의 환경에서 새로운 기법들로 보여질 수 있는 연구가 활발히 진행되고 있다. 본 논문에서는 이기종 환경에서 임의의 OpenGL 기반의 PC 게임이나 게임 뷰어가 있는데서 Java3D 형태로 재복원해서 볼 수 있는 방법과 VRML을 사용하여 캡쳐된 장면들을 네비게이션 해 봄으로써 프레임간 오브젝트들의 움직임을 비교 분석할 수 있는 방법을 제안한다. 결과적으로 구조적인 장면 그래프에서 사건을 처리하고, Parser에서 OpenGL Primitive들의 정점 정보를 해석해서 계층구조를 변화시킴으로서 보다 빠른 실시간 렌더링을 구현하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2021.05a
• /
• pp.483-486
• /
• 2021

기존의 심층 강화학습은 상태, 행동, 정책 등을 모두 벡터 형태로 표현하는 강화학습으로서, 학습된 정책의 일반성과 해석 가능성에 제한이 있고 영역 지식을 학습에 효과적으로 활용하기도 어렵다는 한계성이 있다. 이러한 문제점들을 해결하기 위해 제안된 새로운 관계형 강화학습 프레임워크인 dNL-RRL은 상태, 행동, 그리고 학습된 정책을 모두 논리 서술자와 규칙들로 표현할 수 있다. 본 논문에서는 dNL-RRL을 기초로 공장 내 운송용 모바일 로봇의 제어를 위한 행동 정책 학습을 수행하였으며, 학습의 효율성 향상을 위해 인간 전문가의 사전 영역 지식을 활용하는 방안들을 제안한다. 다양한 실험들을 통해, 본 논문에서 제안하는 영역 지식을 활용한 관계형 강화학습 방법의 학습 성능 개선 효과를 입증한다.