• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.1
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• pp.71-77
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• 2003

본 논문에서는 불량 하드디스크 드라이브의 수리판정 자동화를 위해 필요한 하드디스크 드라이브(Hard Disk Drive, HDD) 결함의 분포패턴의 분류에 관한 연구 결과를 소개한다. HDD 제조공정에서는 테스트 진행 중 검출된 결함에 관한 정보를 HDD 내부에 기록한다. 불량으로 판별된 HDD는 내부에 기록된 결함의 분포론 관찰한 후, 불량의 종류 및 그에 따른 처리방안을 결정한다. 본 논문에서는 효율적인 결함분포 패턴의 특징추출을 위해, 하드디스크의 물리적 특성에 대한 분석을 바탕으로 극좌표 (Polar Coordinates) 방식으로 표현된 결함 위치 데이터를 직교좌표(Cartesian Coordinates)로 변환한다. 그리고 디스크 상의 두 동심원 사이의 공간을 정해진 회전각별로 등분한 후, 나누어진 구간별로 결함 발생빈도 히스토그램 (Histogram) 분석을 수행하여 결함분포의 패턴을 분류하는 알고리즘을 제시한다. 설계된 알고리즘은 실제 HDD 제조공정에서 발생한 불량 HDD Set을 대상으로 적용한 결과, 그 효용성이 검증되었다.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.620-625
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• 2007

Autofrettage process is used for internal forming and sizing of cylinder designed to withstand high internal pressures. Once the tube is autofrettaged, it needs to be machined to its final dimensions both at the bore and its outer surface. This paper presents an analytical analysis and numerical analysis of machined compound cylinder using finite element code, ANSYS10.0. An analytical model for predicting the level of autofrettage following either inner, outer, or combined machining of the compound cylinder is developed for the autofrettage residual stress field is simulated by an autofrettaged pressure. The autofrettaged pressures are obtained by using trying-error method. As autofrettage percentage is 20 %, the numerical results are found to be in almost agreement with the analytical ones. However, as autofrettage percentage is 60 %, the numerical results have a little difference with the analytical ones.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.226-231
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• 2007

This paper studied on the impact fracture modeling techniques of spherical dome with MACOR glass-ceramic. The glass ceramic material has bigger compressive strength than the tensile strength and endure well at high temperature. The fracture simulation under shock perssure was performed by the finite element method with nonlinear code LS-Dyna. The simulation was carried out by 3 type dome models under step impact pulse shape. 4-node shell element and 8-node solid element were used for analysis.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.709-712
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• 1996

Generating a project network of a specific construction project is very time consuming and difficult task in the field. To effectiviely automate and support the planning process, we design a case-based project planning expert system inspired by the fact a human expert project planner uses previous cases for planning a new project. A construction project case consist of its specific characteristics and the corresponding project network (i.e. project plan). Using frame based representation. we represent the project features affecting the progress network and the entities composing the project plan such as the buildings, construction methods, WBS (work breakdown structure), activities, and resources. The project planning process runs through most similar case retrieval, case adaptation, and user requirement satisfaction. We represent the construction domain knowledge for each procedure using constraints and rules. We develop the methodology for constraint-based case adaption. Case adaptation process mainly consist of activity generation/deletion and predecence constraint satisfaction, for which we develop the dynamic constraint generation method and connect user-level requirement representation the system-level network modification knowledge. The methodology is being applied to the prototype for apartment construction project planning.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.771-774
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• 2000

Coiling processes of filaments need precise work and standardization. It is important to maintain equal pitch of filaments. Uniform pitch of filaments is one of the dominant elements of life time and efficiency of bulbs. First coiling process of filament wires is modeled by nonlinear contact problem between filaments and mandrel. Analysis of coiling process using finite element method is conducted to consider manufacturing parameters and pitch distance is calculated under the given conditions. Also image detecting system is developed to inspect uniformity of pitch. This system will be used to inspect quality of filaments during coiling processes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.92-97
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• 2012

Injection mold is a manufacturing process used to produce parts of complicated shape at a low cost. Many factors affect the quality of injection molded part during injection molding process. A study on the optimization of injection mold is progressed by using a simulation software like Moldflow. Filling, packing and cooling phases of injection molding processes are analyzed according to the mold design considering the shrinkage of molded part, the degree of filling rate and the wearing of a mold. Taguchi method is applied to analyze the significance of processing parameter and the dynamic characteristics according to the variation of processing parameters. From the results, the mold temperature and packing pressure influenced the shrinkage of injection molded part.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.1
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• pp.63-69
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• 2008

A fatigue test on the steel welded L-shaped frame was conducted. The frame was consisted with carbon steel tube and reinforced bracket. The four type reinforced brackets were fabricated. They were two rectangular plate reinforced bracket, two sided pentagon plate reinforced bracket, triangular plate reinforced bracket and fully reinforced bracket. The fatigue test of frame was conducted with axial tension loading. The fatigue simulation of the steel welded L-shaped frame was also performed by the finite element method with code FEMFAT. The frame of fully reinforced bracket had the highest fatigue life and reinforced quality factor.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.311-313
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• 2012

Many efforts have been made and many tools have been developed in order to manage construction projects by a smart device such as a smart phone and smart pad. This research proposed a method to manage construction schedules via a smart device using Flash. The interactive and graphic property of Flash enables a field manager to manage schedules easily and efficiently. A prototype was implemented by Adobe Flex Builder, and it applied a sample network in a smart pad. Further studies would develop network diagrams such as CPM(Critical Path Method).

• 한국유가공학회:학술대회논문집
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• 1997.10a
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• pp.1-49
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• 1997

HACCP팀은 모든 종사자(소유자 포함)에 대한 기구조직표, 역할분담 및 인수인계사항을 작성하고 모든 종사자는 사전에 HACCP system에 대해 충분히 이해시킬것. 또한 자체 위생관리현황이나 법적 관련규정을 정확하게 이해할 것. HACCP(준비)팀은 HACCP system의 적용을 위한 식품 품목 또는 유형, 시설, 공정단계, 지역 및 위해요인 종류의 범위를 정확하게 결정하여 문서화할 것. 제품설명서와 공정흐름도는 이후 단계에 매우 중요한 기초정보를 제공한다. 따라서 현장을 확인하는 등 사실에 입각하여 정확하게 작성할 것. 위해분석은 인내심을 가지고 현실성을 고려한 충분한 기초자료를 이용하여 정확하게 수행할 것. CCP의 결정전에 위해방지방법, 허용수준, 관리자를 결정하고 해당공장내이 현실성을 고려하여 CCP를 결정할 것. 관리기준 및 허용오차는 물리화학적 인자에 대하여 충분한 기초자료를 통해 설정할 것. CCP에 대한 모니터링과 개선조치 방법을 6하원칙에 준하여 현장생산종사자 중심으로 구체적으로 작성할 것. 모니터링과 검증은 명확하게 구분하여 관리할 것.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.575-578
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• 2002

원자력 중장기 연구개발 일환으로 수행중인 액체금속로 설계기술개발 프로젝트는 개념 설계분야와 기반기술구축 분야로 구성되어 있는 상호 긴밀한 연계가 강조되기 프로젝트이다. 대과제를 중심으로 각 세부과제 및 분야 내에서 시스템별 인터페이스 등이 종합적으로 관리되어야 할 필요성이 있는 프로젝트이다. 액체금속로 설계기술개발 프로젝트의 연구생산성 향상을 위해 공정계획을 수립하고, 프로젝트 수행 중에 산출되는 연구결과물을 검증하여, 검증된 자료를 프로젝트 수행원들에게 공유할 수 있게 Web WorkFlow를 이용한 자료 검증/공유시스템을 개발하여 운영하고 있으며, 최종적으로 검증된 자료는 데이터베이스를 구축하여 활용하고 있다. 이렇게 함으로써 한국원자력연구소에서 개발증인 액체금속로 설계 기술개발 프로젝트를 최적화된 계획 및 관리를 통하여 연구개발을 수행할 수 있을 것으로 예상된다.