• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.131-133
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• 2005

In this paper, we proposed the program module that expand output points when increased of the output machine for the design of process control system with PLC. In order to incense output points we need the decoding. There is a hardware decoding and a software decoding. In this paper, we proposed the decoding program module which is a software decoding and confirmed feasibility through a simulation.

• 소성∙가공
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• 제9권6호
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• pp.561-566
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• 2000

Recently, the hydroforming technology has been recognized as a general technique in manufacturing industry, especially in automotive industry. Hydroforming is applied to increase strength, and to decrease weight, cost and parts. Hydroforming is based on the inflation of, for Instance, a tube, coupled with axial or radial compression and by subsequent expansion and sizing against the die wall. Expansion, axial feeding, calibration are important parameters in this process. In this paper, the effects of various parameters such as internal pressure, axial feeding and friction on hydroforming of automotive bumper rail have been considered.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.26-29
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• 2008

Recently, the hydroforming of high strength aluminum tubes has many studies and applications in manufacturing industry, especially in automotive industry. But high strength aluminum tube has limited expansion capability at most 15% at normal temperature. New manufacturing process, called hot air forming, is introduced to apply aluminum tube to the automotive sub frame components which have complex shape and require high expansion ratio about 40%. The process is carried out at the elevated temperature above $500^{\circ}C$, so numerous material properties and process parameters related to high temperature should be investigated and determined to get a sound product. In this paper, the hot air forming process of automotive sub frame was investigated. The effect of the forming parameters such as the temperature of tool, axial feeding and gas pressure are analyzes by using explicit finite element method.

• 소성∙가공
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• 제7권1호
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• pp.66-71
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• 1998

The present study is concerned with the hydrostatic extrusion process of copper-clad aluminium bar to investigate the bonding conditions as well as the basic flow characteristics. Considering the bonding mechanism of bi-metal contact surface as cold pressure welding the normal pressure and the contact surface expansion are selected as process parameters governing the bonding conditions, in this study the critical normal pressure required for the local extrusion-the protrusion of virgin surfaces by the surface expansion at the interface-is obtained using a slip line method and is then used as a criteron for the bonding. A rigid plastic finite element method is used to analyze the steady state extrusion process. The interface profile of bi-metal rod is predicted by tracking the paths of two particles adja-process. The interface profile of bi-metal rod is predicted by tracking the paths of two particles adja-cent to interface surface. The contact surface area ration and the normal pressure along the interface are calculated and compared to the critical normal pressure to check bonding. It is found that the model predictions are generally in good agreement with the experimental observations. The compar-isons of the extrusion pressure and interface profile by the finite element with those by experi-ments are also given.

• 한국분말재료학회지
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• 제23권1호
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• pp.26-32
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• 2016

Powder injection molding (PIM), which combines the advantages of powder metallurgy and plastic injection molding technologies, has become one of the most efficient methods for the net-shape production of both metal and ceramic components. In this work, plasma display panel glass bodies are prepared by the PIM process. After sintering, the hot isostatic pressing (HIP) process is adopted for improving the density and mechanical properties of the PIMed glass bodies. The mechanical and thermal behaviors of the prepared specimens are analyzed through bending tests and dilatometric analysis, respectively. After HIPing, the flexural strength of the prepared glass body reaches up to 92.17 MPa, which is 1.273 and 2.178 times that of the fused glass body and PIMed bodies, respectively. Moreover, a thermal expansion coefficient of $7.816{\times}10^{-6}/^{\circ}C$ is obtained, which coincides with that of the raw glass powder ($7.5-8.0{\times}10^{-6}/^{\circ}C$), indicating that the glass body is fully densified after the HIP process.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.131-134
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• 2004

The hub hole is usually formed with a stretch flanging process followed by a blanking process of a hole. Since the hole is made by blanking, the blanked surface is so rough that the formability in the region is rather poor. The emerging task is to identify the formability of the blanked region in the forming simulation and to relate the criterion to the real forming process by experiments. In this paper, the blanked region of a hole surface is modeled by a defected-edge finite element for stretch flanging simulation. The analysis deals with the level of defect in the blanked region in order to identify the formability in the real process. The analysis provides the formability depending on the level of defect and seeks the way to match the level of defect to that of the real surface. The approach makes the analysis possible to deal with the formability of the high strength steel and predict the fracture at the hole surface during the stretch flanging simulation.

• 산업기술연구
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• 제22권B호
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• pp.35-44
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• 2002

To find the optimal solution as rapidly and exactly as possible with Nelder-Mead simplex algorithm, the present values of the reflection, expansion, contraction and/or shrink parameters of this algorithm are needed to be changed at appropriate time during the search process. The reflection parameter is selected in this study in order to be changed because reflection, expansion and contraction process can be simultaneously effected by only this parameter. Two independent indices for determining whether the present value of the reflection parameter of this algorithm should be changed or not during the search process are suggested in this study. Those indices were made of the equations of Nelder-Mead simplex algorithm's convergence criterion and Dennis-Wood's convergence criterion, respectively. It is appeared that the optimal solution can be find with smaller numbers of objective function evaluation than the original Nelder-Mead's one with fixed parameter when the those indices are used during the search process. and the more remarkable reduction effect of the number of an objective function evaluation can be obtained when the latter index is used.

• 한국결정성장학회지
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• 제15권4호
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• pp.162-167
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• 2005

건조공정 중인 다공성 물질의 물성은 재료의 비균질성 즉 전위, 입자, 입계, 균열, 기공과 같은 미시적인 결함인자들의 영향을 받는다. 따라서 다공성 물질의 건조공정을 전산 시뮬레이션하기 위해서는 원자 스케일 해석을 통한 미시적 물성을 알아야 한다. 본 연구에서는 분자동역학 시뮬레이션을 이용하여 원자 모델을 구성하고 원자 상호간 거동을 예측하여 재료의 미시적 물성을 계산하였다. 이렇게 구한 탄성계수, 열팽창계수, 체적 열용량은 실험 및 이론에 기초한 결과들과 비교하여 검증하였다.

• 패션비즈니스
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• 제26권3호
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• pp.98-115
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• 2022

The purpose of study was to analyze the process of accepting by BTS fans. The methodology used in this study was qualitative research using grounded theory and the results of the study follow. As a result of open coding, 47 concepts, 23 subcategories, and 14 categories were derived. In the axis coding stage, the casual conditions were "Recognition of BTS image," "Fascinated by BTS image," "Simple consumption of BTS image," and "Arising and expansion of curiosity about BTS image." The contextual conditions were "Accessibility of BTS image" and "Abundance of BTS image searching paths." The central phenomenon appeared to be "Immersing and studying BTS image." The arbitration conditions were "Capabilities required to reproduce BTS image" and "Motivation for contributing BTS image." The actions/interactions were "Presenting BTS image," "Contribution to the spread of BTS image," and "Involved in forming new BTS image." The result was "Emergence and expansion of new BTS image meaning" and "Strengthening attachment to BTS." Through process analysis, it was found that acceptance of BTS images consisted of five stages: "Recognition of BTS image," "Becoming curious about BTS image," "Searching BTS image," "Intervention of BTS image." and "Reproduction of BTS image." As a result of deriving the core categories through selective coding, the core category was "Forming a bond while participating in the BTS image."

• 정보과학회 컴퓨팅의 실제 논문지
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• 제22권9호
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• pp.461-466
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• 2016

토픽 확장은 학습된 토픽의 질을 향상시키기 위해 추가적인 외부 데이터를 반영하여 점진적으로 토픽을 확장하는 방법이다. 기존의 온라인 학습 토픽 모델에서는 외부 데이터를 확장에 사용될 경우, 새로운 단어가 기존의 학습된 모델에 반영되지 않는다는 문제가 있었다. 본 논문에서는 무한 사전 온라인 LDA 토픽 모델을 이용하여 외부 데이터를 반영한 토픽 모델 확장 방법을 연구하였다. 토픽 확장 학습에서는 기존에 형성된 토픽과 추가된 외부 데이터의 단어와 유사도를 반영하여 토픽을 확장한다. 실험에서는 기존의 토픽 확장 모델들과 비교하였다. 비교 결과, 제안한 방법에서 외부 연관 문서 단어를 토픽 모델에 반영하기 때문에 대본 토픽이 다루지 못한 정보들을 토픽에 포함할 수 있었다. 또한, 일관성 평가에서도 비교 모델보다 뛰어난 성능을 나타냈다.