• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1097-1100
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• 2003

Tunable thermo-optic filter for WDM system was designed and fabricated. The basic structure of the filter was a Fabry-Perot resonator and the center cavity layer was poly-Si. Quardraple layers of low and high refractive index materials were used as DBR mirrors. Tuning and transmission efficiencies was measured and compared with the simulation results. Tuning range of 9.4 nm can be obtained by 64.7$^{\circ}C$ temperature changes and tuning efficiency was 0.144nm/K. The filter is to be assembled onto the micro optical bench with fiber optical path.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.120-125
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• 2008

A flip-chip bonding system using DPSS(Diode Pumped Solid State) Nd:YAG laser(wavelength : 1064nm) which shows a good quality in fine pitch bonding is developed. This laser bonder can transfer beam energy to the solder directly and melt it without any physical contact by scanning a bare chip. By using a laser source to heat up the solder balls directly, it can reduce heat loss and any defects such as bridge with adjacent solder, overheating problems, and chip breakage. Comparing to conventional flip-chip bonders, the bonding time can be shortened drastically. This laser precision micro bonder can be applied to flip-chip bonding with many advantage in comparison with conventional ones.

• Design & Manufacturing
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• v.1 no.1
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• pp.17-21
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• 2007

In the manufacture and processing of large plastic materials, product quality is tested and verified through several techniques such as injection processing, residual stress through injection molding and shrinkage. With regards to the injection molding process, common problems such as inconsistent density is seen when different points of the product are discovered to have varying thickness levels. Sink marks in product are then evident. This occurs when there is poor molding conditions caused about by poor runner and packaging systems incorporated into the process. We designed the runner system which is possible balanced filling to cavities using CAE program $Moldflow^{TM}$ and then obtained optimal processing conditions by Taguchi's Robust Design technique.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.51-54
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• 2002

As digital systems continue to use components with faster edge rate and clock speeds, transmission of the digital information can take place many troubles. The increasing requirement for controlled impedance PCBs becomes both a critical success factor and a design challenge. Especially, the noise sources in digital system include the noise in power supply, ground and packaging due to simultaneous switching of signal, signal reflections and distortions on single and multiple transmission lines. This paper simulates the tracks controlled impedance with the test coupon. So, it can saves the design time and supports the economical PCB design.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1442-1447
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• 2003

Computer is a very powerful machine which is widely using for data processing, DB construction, peripheral device control, image processing etc. Consequently, many researches and developments have progressed for high performance processing unit, and other devices. Especially, the core units such as semiconductor parts are rapidly growing so that high-integration, high-performance, microminiat turization is possible. The packaging in the semiconductor industry is very important technique to de determine the performance of the system that the semiconductor is used. In this paper, the inspection of the inner defects such as delamination, void, crack, etc. in the semiconductor packages is studied. ESPI which is a non-contact, non-destructive, and full-field inspection method is used for the inner defect inspection and its results are compared with that of C-Scan method.

• Annual Conference of KIPS
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• 2005.05a
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• pp.545-548
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• 2005

Linux 응용프로그램들의 확산을 위해서는 인스톨, 다운로드의 번거로움이 없이 서버로부터 PC로 보다 쉽게 서비스 할 수 있는 스트리밍 체계가 필요하다. 이 스트리밍의 중요 부분이 기존 응용프로그램을 수정없이 스트리밍 전송이 가능한 형태로 인덱싱 및 포메팅을 하는 패키징의 과정이다. 기존 패키징 기술은 응용프로그램을 구성하는 직접적인 파일들을 이용하여 구성한다. 응용프로그램과 직접적 상관관계를 갖는 파일들에 대해서는 정보수집이 용이하기 때문에 완전하게 패키징으로 재구성이 가능하나, 간접적 상관관계를 갖는 파일에 대한 정보들은 정보누락이 쉬워서 완전한 패키징으로 재구성이 어려운 문제점이 있었다. 본 논문에서는 Stackabe file system의 기법을 활용하여 한 응용프로그램과 간접적 상관관계를 갖는 정보수집을 보다 더 정확하게 하는 방법을 제시하였으며, 이를 활용하여 보다 완전한 패키징이 가능하도록 하는 방법에 대해서 논의한다

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.938-944
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• 1994

Active damping has been shown to offer increased suspension performance in terms of vehicle isolation, suspension packaging, and road-tire contract force. Many semi-active damping strategies have been introduced to approximate the response of active damping with the modulation of passive damping parameters. This study investigates the characteristics of semi-active suspension control through the simulation of passive, skyhook active, and semi-active damping models. A quarter car model is studied with the conrolled damping replacing both passive and active damping. A new semi-active scheme is suggested to eliminate the abrupt changes in semi-active damping force. It is shown that the new strategy performs almost identically to the so called "force controlled" semi-active law without steep changes in damping force or body acceleration.eleration.

• Journal of Korean Society for Quality Management
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• v.27 no.2
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• pp.183-200
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• 1999

ndustrial development began to cause serious pollution problems. Most of the environmental problems are related with operations of industrial companies. Environmental problems should be considered at all the stages of business activities or processes, from product design to new forms of packaging, from marketing to disposal. This paper suggests that how to cope with environmental issues is an important factor in the global market, and environmental management has become one of the key success factor. Through the survey of P&G's environmental management, it is intended to provide a chance to benchmark or give a cue on how to conduct the environmental management.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.69-72
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• 2001

High-level synthesis generates a structural design that implements the given behavior and satisfies design constraints for area, performance, power consumption, packaging, testing and other criteria. Thus, high-level synthesis generates that register-transfer(RT) level structure from algorithm level description. High-level syntehsis consist of compiling, partitioning, scheduling This paper we study the partitioning process, and analysis the min-cut algorithm and simulated annealing algorithm.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.3
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• pp.120-129
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• 2001

A two-degree-of-freedom quarter-car model is used as the basis for LQ and the proposed controller design for a semi-active suspension. The LQ controller results in the best rms performance trade-offs(as defined by performance index) between ride, handling and packaging requirements. In LQ controller, however, the conflict between road holding and ride comfort remains. The adaptive semi-active suspension control based on the road frequency are introduced in this paper. With this method, the trade-off between road holding and ride comfort can be relaxed. The road frequency is estimated by wavelet transform if rattle space signal. The simulation results show that the proposed controller is superior to the conventional LQ controller.