• Journal of Digital Convergence
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• v.10 no.2
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• pp.225-229
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• 2012

A reformer for a small fuel cell system is an apparatus which converts hydrocarbon fuel into hydrogen-rich gas. Among many indices of a reformer, the most crucial index of a reformer is CO concentration in the off-gas out of reformer which must be controled under 5ppm for the efficiency and performance of a system. This paper suggests the criteria of a reformer operation for the stability of a reformer in a fuel cell system by deducing crucial indices and improving processes. The six-sigma technique was applied to verify the optimum control and operation of a reformer of a fuel cell combined heat and power system. The result of temperature control of each parts of a reformer system is the concentration of CO which is the most important factor for the operation of a fuel cell system. The temperature of the parts of a reformer, MTS, LTS and Prox, were controled so that the concentration of CO.

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.276-286
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• 2008

The representative alignments for taking a stereo image by using a stereoscopic camera are the toed-in and the parallel alignment. In this paper, we tried to find important factors in the process that captures the stereo image by modifying parallel type 3D camera alignment to take the same object information as, for instance, when toed-in type was used. The modified parallel type 3D camera has merits in both types. As a result, three important factors are found by simulation to be inter-camera distance, field of view and convergence angle for both types. And the change of the convergence angle is known to be the most important factor at the stereo fusible area in processing. The effective ranges of these factors to simulate perfectly toed-in type by modified parallel type are strongly dependent on a user's circumstances such as mobile, official, theater and so on. Additionally, the error of the simulation is reduced when the focal length of the stereo camera is short and the convergence angle becomes smaller.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.185-191
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• 2023

Research to analyze the future prediction of value is being conducted in various. However, it was found through the research results of each field that such future value analysis has too many variables according to each field, so the accuracy of the prediction result is low, and it is difficult to find objective key influencing factors that affect the result. In particular, since objective standards for the importance of various influencing factors have not been established, the key influencing factors have been judged and applied based on the researcher's subjectivity. Accordingly, there is a need for a reasonable process model for extracting key influencing factors that affect the prediction of volatility goods value that can be objectively applied in various fields. In this study, process modeling for extracting key influencing factors was conducted in seven steps, and the method for extracting key influencing factors was explained in detail in each step. In addition, as a result of simulation by applying Ni metal among the major variable goods in the field of raw materials using the proposed modeling, the predicted value by the existing method was 0.872% and the predicted value by applying the modeling of this study was 0.864%. conformance was confirmed.

• Journal of the KSME
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• v.33 no.11
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• pp.936-941
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• 1993

최근 소비전력 구제 및 $CO_{2}$ 발생량 구제 등으로 인하여 에너지 절약형 제품에 대한 요 구가 점증하고있어 핵심부품인 열교환기의 효율 향상은 숙명적인 과제라 할 수 있다. 에어컨에 사용되고 있는 응축기와 증발기(condenser/evaporator)는 대부분이 핀-튜브(fin-tube)형의 직교 류형 열교환기 (crossflow heat exchanger)이다. 이와 같은 열교환기의 성능에 영향을 미치는 인자들은 크게 핀과 튜브로 구성되는 기하학적인 인자와 공기부와 냉매부로 나뉘어지는 물리적인 인자로 나눌 수 있다. 이 글에서는 핀-튜브형 열교환기의 설계시 고려하여야 할 기하학적 인자와 물리적 인자에 대하여 기술하고자 한다.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.70-79
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• 2012

The Korean Government recently has been focused on strengthening competitiveness of order and stimulating construction market in the international construction industry. It has planned to extend the ODPs (overseas development projects) in order to diversifying the international construction market of which is domestic construction companies, placing too much emphasis on plant projects of the Middle East. However, literature review of risk analysis in the ODPs shows that the number of case study is several. Therefore, Authors asserted the necessity of risk analysis in the ODPs. The purpose of this study is to suggest a methodology that find KRFs (key risk factors) in the ODPs and analyze them, using AHP and Fuzzy theory. As a result, the 37 KRFs are selected and explained characteristics of them. A future direction of this study is to suggest a risk management model in the ODPs and prove feasibility of it.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.73-73
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• 2022

전 세계적으로 발생하고 있는 기후변화로 인하여 자연재해가 빈번한 실정이며, 특히 가뭄은 농업용수 부족과 직결되어 식량안보를 위협하는 요소가 되고 있다. 최근 우리나라에서도 통합물관리 정책 추진과 더불어 농업용수의 물절약 필요성이 강조되고 있으며, 농업용수 수요관리를 위한 실사용자인 농업인과 이해관계자들의 관심과 노력이 필요한 상황이다. 따라서 농업용수의 지속가능성 확보를 위한 물이용 절감 등 적극적인 수요관리를 위해 농업용수 거버넌스 구축이 요구되고 있다. 이에 본 연구에서는 우리나라 농업 현장에 적용 가능한 농업용수 거버넌스 구축에 필요한 주요 구성 인자를 파악해 보았다. 이를 위해 국내외의 농업 및 농촌 거버넌스 사례와 문헌조사 등을 통해 농업용수 거버넌스 구축을 위한 6개의 주요 인자를 선정한 후, 전문가를 대상으로AHP(Analytic Hierarchy Process) 방법을 이용한 설문조사 및 쌍대비교를 통해 우선순위를 도출해 보았다. 그 결과, 총 6개 주요 인자의 중요도는 '핵심주체', '법률 및 정책 구축', '예산 지원', '정보공유 및 커뮤니케이션', '상호 학습', '외부전문가' 순으로 도출되었다. 여기서 가장 높은 중요도를 차지한 '핵심주체'는 농업인을 의미하며, 이는 공사에서 담당하고 있는 현재의 공적관리체계로는 필지단위의 효율적 물관리에 한계가 있으므로, 물 사용의 주체인 농업인의 물관리 참여를 위한 거버넌스 운영에 농업인이 핵심주체로서의 역할을 하는 것이 필요하다는 것을 나타낸다. 농업인 중심의 상향식 거버넌스(Bottom-up governance) 방식으로 농업용수 거버넌스가 운영된다면, 농업용수 이해관계자들의 관심과 농업인의 자발적인 물절약 참여를 유도할 수 있을 것으로 판단된다. 또한 거버넌스 운영을 통하여 농업인 및 이해관계자의 소통과 문제 제기 및 환류 노력 등을 통해 물절약을 위한 제도개선 및 현장 실천 노력 등이 지속적으로 이루어진다면, 농업용수 지속가능성 확보에 긍정적인 효과를 나타낼 수 있을 것으로 사료된다.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.130-135
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• 2013

Until now, passenger airbag design is based on the referred car design and many repetitive crash tests have been done to meet the crash performance. In this paper, it was suggested a new design process of passenger airbag. First, key performance factors were determined by analyzing the injury risk effectiveness of each performance factor. And it was made a relationship between injury risk and performance factor by using the response surface model. By using this one, it can be predicted the injury risk of head and neck. Predicted injury risk of optimal design was obtained through this injury risk prediction model and it was verified by FE analysis result within 18% error of head and 9% error of neck. It was shown that a target crash performance can be met by controlling the key performance factors only.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.2
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• pp.37-42
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• 2005

Recently $6{\sigma}$ quality control is an most important strategy to many enterprises in order to be a top company in the world, because it is an excellent scientific method to achieve the best quality control for their management and products. SY company is a small and medium one that has the quality problem for a long time such as occurring cracks on the surface of commutator at his assembly line while being assembled a rotor shaft and commutator of DC motor. This research was started to improve this problem by $6{\sigma}$ process, and as the results of this study, first, to find three vital fews, second, to get an achievement of about 21% improvement for the fracture strength of commutator, and third, to be recognized to change into $6{\sigma}$ quality control in SY company.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.503-503
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• 2007

본 논문에서는 지중배전(22.9kV) 선로에 사용되는 지상변압기를 대상으로 수행한 방열해석 및 개선과 변압기수명연장에 관한 검토 결과를 수록하였다. 변압기의 열화메커니즘에 대한 문헌 조사를 통해 변압기 온도와 수명간의 관계를 작도하였는바, 수명 평가를 위한 핵심 인자로 열에 의한 절연지의 열화에 초점을 맞추었다. 기존 외함에 설치된 방열구중 상부 위치를 상부판에도 변경하는 경우 약25%의 통풍량 증가 효과를 기대할 수 있을 것으로 평가 되었으며 상부판과 내함 사이에 형성되던 고온 영역에서의 온도를 약$15^{\circ}C$정도 낮출 수 있는 것으로 나타났다. 절연지의 인장강도 변화로 평가한 수명예측 곡선에 따르면 약$10^{\circ}C$의 은도 저감은 약10배의 수명 연장 효과를 가져오는 것으로 나타난바, 본 연구에서 확인한 방열구의 위치 변경에 따른 지상기기 내부의 온도 저하는 변압기 수명을 연장하는데 일조할 것으로 기대된다. 기존 지상변압기에서의 방열구조를 통해 변압기 온도와 수명간의 관계를 작도하였는바, 수명 평가를 위한 핵심인자로 효과적으로 방열할 수 있는 새로운 외함의 구조 및 디자인을 제시하고 시뮬레이션을 통해 개선효과를 예측하였다. 또한, 개선된 모델을 가지고 실제 변압기를 제작한 후 부하를 인가하여 개선전과 후에 대한 방열효과를 실증시험을 통해 확인하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1153-1160
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• 2016

There have been many studies on the subject of risks in the Construction Industry and many useful results have been produced. However, risk studies on the conditions of contract, which is the most critical contract documents, has not been tried despite of its contractual function in the overseas projects. In this study, various contractual risks are identified for proper and reasonable evaluation of the contractual risks possibly encountered in the Tender and/or Contract stages of the Projects. For development of study, FIDIC Red Book 1999 Edition which is world widely recognised as a standard conditions of contract prepared for the projects designed by the Employer. Contractual risks are divided into three levels and applicable clauses are assigned to each appropriate risk factors. And table of major contractual risk factors are made using the classified levels of each factors with evaluation criteria as a result of this study. As this study is made only for the conditions of contract which is prepared for the construction contracts designed by the Employer, further studies for other types of contracts such as Design-Build (FIDIC Yellow Book), EPC/Turnkey (FIDIC Silver Book) and recently developed Design, Build and Operate type of contract (FIDIC Gold Book) are required to cover various types of projects executed in the world construction markets.