• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.67-68
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• 2016

In construction management, BoQ(Bill of Quantities) has been commonly used for the cost estimation. However, many problems have been recognized about the work items used in the BoQ that could be varied by the experience and knowledge of the estimators or the project. Also, there are lots of work items that have to be written in BoQ even though the cost proportion of those items is relatively lower than the others. In this study we consider the way how to organize optimally the work items through the analysis of case. The results of this study could be useful for improving the efficiency of preparing construction BoQ and conducting Quantity take-off in our construction management practices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.312-315
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• 2003

Basic design of RC-GCTs (Reserve-Conducting Gate-Commutated Thyristors) by novel punch-through (PT) concept with 5,500v rated voltage is described here. A PT and NPT (non punch-through) concept for the same blocking voltage has been compared in detail. The simulation work indicates that GCT with such PT design exhibits that the forward breakdown voltage is 6,400V which is enough for supporting 5500V blocking. Additionally, the real IGCT turn-off in the mode of PNP transistor has been realized. However, the carrier extraction from N-base to gate terminal will be drastic slowly in terms of NPT structure except for the high on-state voltage drop.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.412-415
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• 2003

[ $Si_3N_4$ ] thin film is the good material to fabricate the capacitors at MMIC processes. Normally, $Si_3N_4$ thin films is used to dielectric in the MIM capacitor and film thickness is $2000\;{\AA}$. Insulator(or dielectric) was deposited by PECVD at our MIM structure with air bridge which connect between top metal and contact pad. We optimized PECVD process to fabricate the good capacitors which can be applied at the true MMIC. The thickness of our $Si_3N_4$ thin films was $1000\;{\AA}$ shallower than $2000\;{\AA}$, and their breakdown voltages were above 70V.

• Journal of the Korean Society of Systems Engineering
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• v.2 no.1
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• pp.48-53
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• 2006

A web-based program life-cycle management(PLM) system is introduced to implement the system engineering processes and to provide the development traceability online. This information system aims for the realization of essential system engineering management techniques currently applied to the space launch system development program including management of configuration and data based on the work breakdown structure(WBS), WBS, bill of materials and mass properties. The system enhances communication and gives access to the development data with relevant information such as data-to-data relation and approval status/history through the web, and preserve all of the development data throughout the program life-cycle. Further improvement of the system is planned to implement the program management processes and co provide integrated information useful for the programmatic decision making.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.247-248
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• 2006

In this study, the morphology of the change of primary Al phase in A356 alloy by two kinds of electromagnetic stirrers(vertical and horizontal) were investigated to obtain the globular structure. The effects of the stirring current, the stirring time and the pouring temperature were determined. The greater stirring current and longer stirring time were to get the finer the Al phase. However, over a certain stirring current and stirring time, the primary Al was merged together and was increased. The reason is the degree of breakdown of initial dendrites has been decreased by the collision and coalescence of particles with increasing stirring current and stirring time. The optimum conditions and difference of the two kinds of electromagnetic stirrers have been investigated for rheology forming with controlled solid fraction.

• Applied Science and Convergence Technology
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• v.27 no.2
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• pp.23-25
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• 2018

With respect to the electrode structure and the discharge characteristics, the atmospheric pressure plasma sheet of a thin polyimide film is introduced in this study; here, the flexible plasma device of a dielectric-barrier discharge with the ground electrode and the high-voltage electrode formulated on each surface of a polyimide film whose thickness is approximately $100{\mu}m$, that is operated with a sinusoidal voltage at a frequency of 25 kHz and a low voltage from 1 kV to 2 kV is used. The streamer discharge is appeared along the cross-sectional boundary line between two electrodes at the ignition stage, and the plasma is diffused on the dielectric-layer surface over the high-voltage electrode. In the development of a plasma sheet with thin dielectric films, the avoidance of the insulation breakdown and the reduction of the leakage current have a direct influence on the low-voltage operation.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.560-564
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• 2009

절도시설과 같은 광역지역 공사 현장에서는 다양한 요인을 갖는 공종별 위험요소가 존재하고 있으나, 현장에서 이를 효율적으로 관리할 수 있는 방안의 수립이 미흡한 실정이다. 따라서 본 연구에서는 철도 관련 실무자들을 대강으로 설문조사를 실시하여 공종별 위험 요인을 도출한다. 이를 통해 RBS(Risk Breakdown Structure)를 구축하고 제시된 RBS에 의한 위험도를 산정한 후 이를 기반으로 VR시스템과의 연동 및 위험관리 체계 구축 방법론을 제시하고 있다. 따라서 현장에서의 주요 공종별 Risk 위험도를 가상환경에서 구현이 가능하므로 위험요인에 따른 시설의 직관적 파악이 가능하다. 또한 시공자들은 나타난 시각화 정보에 의한 Risk에 대비해 효율적인 공사 관리를 이행할 수 있을 것으로 기대된다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.441-444
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• 2008

메가프로젝트(Mega-Project)는 다양한 유형의 시설군을 복합 개발하는 건설사업으로서 규모가 크고 복잡한 경우가 많기 때문에 종합적인 사업관리에 어려움이 따른다. 따라서 메가프로젝트는 기존의 단위프로젝트 수준이 아닌 프로그램 수준에서의 관리체계를 필요로 하며 그에 적합한 업무분류체계(WBS)를 구축해야 한다. 업무분류체계는 사업관리를 위한 전체적인 구조를 수립하는 기반으로서, 현재 프로그램 관리 수준의 업무분류체계의 기준이 갖추어지지 않은 상황이다. 이에 본 연구에서는 메가프로젝트를 위한 업무분류체계기준(WBS Basis)를 개발하여 메가프로젝트의 업무분류체계 구축을 지원하고자 한다. 메가프로젝트 생애주기에 포함되는 전체 시설군, 업무 및 용역, 기록문서, 정보 등을 대상으로 하였으며, 기존 사례분석과 관련 분류체계들을 바탕으로 초안을 작성하였다. 이후 현장시험을 통한 검증을 거쳐 최종 업무분류체계기준을 완성하였고 분류내용과 활용방안을 소개한다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.967-968
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• 2006

This research reports for the successful consolidation of $Al_2O_3$ powder with retained ultra-fine structure using MPC and sintering. Measurements in the consolidated $Al_2O_3$ bulk indicated that hardness, fracture toughenss, and breakdown voltage have been much improved relative to the conventional polycrystalline materials. Finally, optimization of the compaction parameters and sintering conditions will lead to the consolidation of $Al_2O_3$ nanopowder with higher density and even further enhanced mechanical properties.

• Journal of the Korean Society of Systems Engineering
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• v.1 no.1
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• pp.53-60
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• 2005

System engineering(SE) management techniques applied for space launch system development are introduced to assess the current status and address the effectiveness of these techniques. Management plans and guides are prepared for the work breakdown structure, data, configuration, interface control, quality assurance, procurement, reliability, risk and verification/validat ion. Further improvement is required for the system engineering management plan(SEMP) to merge the international cooperation into current engineering management system.