• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.3
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• pp.313-318
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• 2001

To establish nondestructive test method for aerospace composite materials, various composite specimens were tested and analyzed using acoutic emission. The hit rate of acoustic emission closely was rotated with crack initiation and propagation. This report also presents defection capability of crack initiation pressure, initial crack active location, and crack propagation using acoustic emission.

• Composites Research
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• v.33 no.2
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• pp.50-54
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• 2020

Soft robotics and wearable devices require large motions and flexibility. In this regard, there is a demand for developing stretchable strain sensors which can be attached to the soft robots and wearable devices. In this work, we fabricated stretchable and electrically conductive composite fibers by combining polyurethane (PU) and silver nanoflowers (AgNFs). The PU/AgNF composite fibers showed the change of the resistance as a function of the applied strain, demonstrating the potential for stretchable strain sensors in soft robotics and wearable devices. The mechanical and electrical characteristics of the composite fibers were measured and analyzed to use the composite fibers for stretchable strain sensors.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.333-338
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• 2006

본 연구는 현재 디젤발전기를 전원으로 사용하고 있는 도서지역에 신 재생에너지원의 조합으로 구성 된 발전시스템 보급의 경제성 분석을 검토해 보았다. 분석 대상 도서는 에너지 기술연구원의 풍속분포자료를 근거로 추자도, 거문도, 영산도를 선정하였으며, 풍속 그 외 일사량, 부하 자료는 부분적으로 실측된 자료를 바탕으로 재구성하고 시스템 구성 발전기 들의 비용 자료는 해외 시장의 자료를 이용하였다. 분석을 위한 도구로는 도서지 역 에서 단독으로 운영되는 신 재생복합 전력시스템의 최적 설계 및 운영을 위한 프로그램으로 해외의 여러 곳에서 활용 중인 Homer를 사용하였다. 분석 결과, 추자도와 거문도 지역에 신 재생복합 전력시스템을 도입 할 경우에는 도서지역의 신 재생복합 전력시스템 보급이 경제 적인 사업으로 나타났지만 신 재생에너지 원인 풍속이 낮은 값을 가지는 영산도의 경우에는 신 재생복합 전력시스템의 보급이 디젤발전기만 운영 할 경우보다 발전 단가를 높인다. 즉, 신 재생에너지 원이 조건에 맞을 경우에는 도서지역의 신 재생복합 전력시스템 보급이 경제 적인 사업이라고 볼 수 있지만 영산도의 경우와 같이 그렇지 않을 경우엔 기존의 시스템보다 발전단가를 높일 수 있으므로 도서지역에 대한 충분한 모니터링을 거친 후에 부지를 선정 해야 한다.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.69-76
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• 2019

In this study, resin flow analysis of resin transfer moulding (RTM) method was performed for mould design of composite structure. The target composite structure was a tank used for fluid storage. Natural c fiber composite was adopted for composite structural design of the fluid storage tank. RTM was adopted for manufacturing of the tank using natural fiber composites. Resin flow analysis was performed to find the proper RTM conditions of the tank. The resin flow analysis was performed using the commercial FEM flow simulation software. After repeated analysis while changing the location of resin inlet and outlet, the proper resin filling time and pattern were found.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.233-243
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• 2008

Recognition for the importance and roles of public transportation is increasing because of traffic problems in many cities. In spite of this paradigm change, previous researches related with public transportation trip assignment have limits in some aspects. Especially, in case of multimodal public transportation networks, many characters should be considered such as transfers. operational time schedules, waiting time and travel cost. After metropolitan integrated transfer discount system was carried out, transfer trips are increasing among traffic modes and this takes the variation of users' route choices. Moreover, the advent of high-technology public transportation card called smart card, public transportation users' travel information can be recorded automatically and this gives many researchers new analytical methodology for multimodal public transportation networks. In this paper, it is suggested that the methodology for establishment of brand new multimodal public transportation networks based on computer programming methods using transportation card data. First, we propose the building method of integrated transportation networks based on bus and urban railroad stations in order to make full use of travel information from transportation card data. Second, it is offered how to connect the broken transfer links by computer-based programming techniques. This is very helpful to solve the transfer problems that existing transportation networks have. Lastly, we give the methodology for users' paths finding and network establishment among multi-modes in multimodal public transportation networks. By using proposed methodology in this research, it becomes easy to build multimodal public transportation networks with existing bus and urban railroad station coordinates. Also, without extra works including transfer links connection, it is possible to make large-scaled multimodal public transportation networks. In the end, this study can contribute to solve users' paths finding problem among multi-modes which is regarded as an unsolved issue in existing transportation networks.

• The Science & Technology
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• s.508
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• pp.62-64
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• 2011

• Computational Structural Engineering
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• v.33 no.2
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• pp.35-40
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• 2020

• Composites Research
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• v.18 no.3
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• pp.59-64
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• 2005

• Construction Engineering and Management
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• v.8 no.4
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• pp.27-30
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• 2007

• KOREAN POULTRY JOURNAL
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• v.48 no.4
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• pp.160-163
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• 2016