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6-도메인 스마트팩토리 성숙도 평가 모델 기반 도입기업 군집분석
정도현,안정현,최상현,Jeong, Doorheon,Ahn, Junghyun,Choi, Sanghyun 한국융합학회 2020 한국융합학회논문지 Vol.11 No.9
스마트팩토리는 가장 빠르게 발전하고 변화하는 4차 산업혁명 분야 중 하나이다. 스마트팩토리에서 도입정도와 성숙도 수준 평가는 중요한 부분에 해당한다. 본 논문에서는 국내 스마트팩토리를 도입한 중소기업들을 대상으로 설문 조사를 진행한 데이터를 바탕으로 스마트팩토리 도입 현황과 새로운 성숙도 평가 모델 기반 군집분석을 진행하였다. 설문에 응한 스마트팩토리 도입 기업의 약 68% 기업들이 기초수준에 해당하였고, 21% 정도만이 중간1 수준이었다. 대다수 중소기업들이 중간1로 진입하지 못한 가장 큰 이유로 자금부족을 꼽았다. 군집분석 결과, 군집별 패턴은 유사하지만 정도의 차이에 따라 '상, 중, 하' 3개로 군집됨을 확인할 수 있었고, 6 도메인 중 프로세스가 상대적으로 성숙도가 가장 높았고, 데이터가 가장 낮은 수준을 보였다. 이를 통해 6개 도메인 기반 새로운 스마트팩토리 성숙도 평가 모델을 활용하여, 보다 구체적이고 정량적인 성숙도 수준 측정 및 분석이 가능함을 보였다. Smart Factory is one of the fastest developing and changing fourth industrial revolution fields. In particular, the degree of introduction and maturity level in the smart factory is an important part. In this paper, a cluster analysis of companies introduced smart factory was performed based on a new maturity assessment model. The 68% of 193 companies surveyed were at the basic level, with only 21% being the middle one. Most SMEs cited lack of funds as the main reason for not entering the middle one. As a result of the cluster analysis, it was found that all clusters had similar patterns but grouped into one of three levels of high, middle, and low depending on maturity level of smart factory operation, and process domain had the highest maturity and data domain was lowest among the 6 domains. Through this, analysis of more specific and quantified maturity levels can be performed using 6-domain smart factory maturity evaluation model.
확률조건의 근사화를 통한 효율적인 강건 최적설계 기법의 개발
정도현,이병채,Jeong, Do-Hyeon,Lee, Byeong-Chae 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.12
Alternative formulation is presented for robust optimization problems and an efficient computational scheme for reliability estimation is proposed. Both design variables and design parameters considered as random variables about their nominal values. To ensure the robustness of objective performance a new cost function bounding the performance and a new constraint limiting the performance variation are introduced. The constraint variations are regulated by considering the probability of feasibility. Each probability constraint is transformed into a sub-optimization problem and then is resolved with the modified advanced first order second moment(AFOSM) method for computational efficiency. The proposed robust optimization method has advantages that the mean value and the variation of the performance function are controlled simultaneously and the second order sensitivity information is not required even in case of gradient based optimization. The suggested method is examined by solving three examples and the results are compared with those for deterministic case and those available in literature.
정도현,이병채,Jeong, Do-Hyeon,Lee, Byeong-Chae 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.1
In order to reduce the variation effects of uncertainties in the engineering environments, new robust optimization method, which considers the uncertainties in design process, is proposed. Both design variables and system parameters are considered as random variables about their nominal values. To ensure the robustness of performance function, a new objective is set to minimize the variance of that function. Constraint variations are handled by introducing probability constraints. Probability constraints are solved by the advanced first order second moment (AFOSM) method based on the reliability theory. The proposed robust optimization method has an advantage that the second derivatives of the constraints are not required. The suggested method is examined by solving three examples and the results are compared with those for deterministic case and those available in literature.
정도현,정재필 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.2
Aluminum (Al) and its alloys have been used widely in a variety of industries such as structural, electronic, aerospace, and particularly automotive industries due to their lightweight characteristic, outstanding ductility, formability, high oxidation and corrosion resistance, and high thermal and electrical conductivity. Al have different kinds of alloys according to the various additional elements system and they should be selected properly depending on their effectiveness and suitability for their particular purpose. The major elements for Al alloys are silicon (Si), magnesium (Mg), manganese (Mn), copper (Cu), and zinc (Zn). In order for Al alloys to use for each industry, it is necessary to study of Al to Al joining and/or the Al to dissimilar materials joining to combine the individual parts into one. Many studies on joining technologies about Al to Al and Al to dissimilar materials have been performed such as press joining, bolted joint, welding, soldering, riveting, adhesive bonding, and brazing. This study reviews a variety of Al alloys and their joining method including its principles and properties with recent trends.
3차원 실장을 위한 TSV의 Cu 전해도금 및 로우알파 솔더 범핑
정도현,쿠마르산토쉬,정재필,Jung, Do hyun,Kumar, Santosh,Jung, Jae pil 한국마이크로전자및패키징학회 2015 마이크로전자 및 패키징학회지 Vol.22 No.4
Research and application of three dimensional packaging technology in electronics have been increasing according to the trend of high density, high capacity and light weight in electronics. In this paper, TSV fabrication and research trend in three dimensional packaging are reported. Low alpha solder bumping which can solve the soft error problem in electronics is also introduced. In detail, this paper includes fabrication of TSV, functional layers deposition, Cu filling in TSV by electroplating using PPR (periodic pulse reverse) and 3 step PPR processes, and low alpha solder bumping on TSV by solder ball. TSV and low alpha solder bumping technologies need more studies and improvements, and the drawbacks of three dimensional packaging can be solved gradually through continuous attentions and researches.
부 최적화 문제의 근사적인 계산을 통한 신뢰도 최적설계 방범의 효율개선
정도현,이병채,Jeong, Do-Hyeon,Lee, Byeong-Chae 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.10
Alternative computational scheme is presented fur reliability based optimal design using a modified advanced first order second moment (AFOSH) method. Both design variables and design parameters are considered as random variables about their nominal values. Each probability constraint is transformed into a sub -optimization problem and then is resolved with the modified Hasofer- Lind-Rackwitz-Fiessler (HL-RF) method for computational efficiency and convergence. A method of design sensitivity analysis for probability constraint is presented and tested through simple examples. The suggested method is examined by solving several examples and the results are compared with those of other methods.
고속전단시험의 표준화를 위한 Sn3.0Ag0.5Cu 솔더볼의 전단특성
정도현,이영곤,정재필,Jung, Do-Hyun,Lee, Young-Gon,Jung, Jae-Pil 한국마이크로전자및패키징학회 2011 마이크로전자 및 패키징학회지 Vol.18 No.1
고속전단시힘의 표준화를 위한 기초 연구의 일부로 Sn-3.0wt%Ag-0.5wt%Cu 솔더 볼의 고속전단특성에 대한 연구를 수행 하였다. 고속전단 시험편 제작을 위해 직경 450 ${\mu}m$의 솔더 볼을 FR4 PCB (Printed Circuit Board) 위에 장착한 후 $245^{\circ}C$ 온도에서 리플로 솔더링을 행하였다. PCB 상의 금속 패드로는 ENIG (Electroless Nickel/mmersion Gold, i.e Cu/Ni/Au)와 OSP (Organic Solderability Preservative, Cu 패드)를 사용하였다. 고속전단 속도는 0.5~3.0 m/s 범위, 전단 팁의 높이는 10~135 ${\mu}m$ 범위에서 변화시켰다. 실험결과로서, OSP 패드의 경우 전단 팁 높이 증가에 따라 연성 파괴가 증가하였으며, 전단속도 증가에 따라 연성파괴는 감소되었다. ENIG 패드의 경우에도 전단 팁 높이 증가에 따라 연성 파괴가 증가하였다. 전단 팁 높이 10 ${\mu}m$(볼 직경의 2%)는 패드 박리 파괴가 대부분이어서 전단파면 관찰에는 부적절한 높이였다. 고속전단에너지는 OSP 및 ENIG 패드 모두 전단 팁 높이 증가에 따라 증가하는 경향을 보였다. Shearing characteristics of Sn-3.0wt%Ag-0.5wt%Cu ball for standardization of high speed shear test were investigated. The solder ball of 450 ${\mu}m$ in diameter was reflowed at $245^{\circ}C$ on FR4 PCB (Printed Circuit Board) to prepare a sample for the high-speed shear test. The metal pads on the PCB were OSP (Organic Solderability Preservative, Cu pad) and ENIG (Electroless Nickel/Immersion Gold, i.e CulNi/Au). Shearing speed was varied from 0.5 to 3.0 m/s, and tip height from 10 to 135 ${\mu}m$. As experimental results, for the OSP pad, a ductile fracture increased with tip height, and it decreased with shearing speed. In the case of ENIG pad, the ductile fracture increased with the tip height. The tip height of 10 ${\mu}m$ (2% of solder ball diameter) was unsuitable since the fracture mode was mostly pad lift. Shear energy increased with increasing shearing tip height from 10 to 135 ${\mu}m$ for both of OSP and ENIG pads.