• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.330-333
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• 2020

장신구 산업은 인건비의 비중이 높고 노동자의 역량에 따라 제품의 제작 작업 시간 및 품질의 편차가 심하다. 이에 산업계의 수요에 맞추어 실리콘 금형 표면 지름 0.75mm 홀에 이어핀을 삽입하는 공정을 자동화하기 위하여 삽입 자동화 시스템이 개발되고 있다. 본 논문에서는 이어핀 삽입 자동화시스템에서 적용할 수 있는 템플릿 매칭 방법과 관심 영역 레이블링을 통한 홀 판별 방법을 제안한다. 제안한 방법의 안정성을 확보하기 위하여 실험을 통해 최적의 매칭 방법과 이진화 기법을 적용하였으며 이어핀 홀의 좌표를 확보하여 X-Y 정밀 이송 시스템에 적용할 수 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.639-644
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• 2015

A cylindrical secondary Li-ion cell is a device in which stored chemical energy is converted to electrical energy via an electrochemical reaction. These cells are widely used for applications that require high capacity and rate power, such as notebooks, power tools, and electric vehicles. The role of a center pin is to retain the channel for gas release, preventing blockage of the hollow of the jelly roll during a charge-discharge cycle, and to prevent an internal short circuit for tearing of separator under mechanical free fall. In this paper, two experiments are conducted with and without the center pin to experimentally verify the importance of the role of the center pin. The first experiment is a 50-cycle charge-discharge cycle test, and the second is a free fall test conducted according to the Underwriters Laboratories (UL) standards. Based on these experiments, we demonstrate that the center pin in a cylindrical cell is a very important component in terms of safety.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.253-256
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• 2007

본 논문은 로봇이 영상을 통해 획득한 특정물체의 기하학적 정보를 이용하여 이족로봇이 안정적으로 보행할 수 있게 하기 위한 균형제어기법을 제안한다. 영상은 핀 홀 카메라 모델을 통해 획득하였으며, 영상에 포함되는 특정물체의 특징성분에 대한 변위와 로봇의 자세와의 상관관계는 핀 홀 카메라 모델을 이용하여 공간좌표계의 특징정보를 평면좌표계의 영상정보에 매칭시킨 후, 특징들의 변위에 따른 로봇 관절 좌표계의 변위를 추정하는 방법으로 구할 수 있었다. 본 논문에서 제안하는 균형제어기법은 별도의 센서없이 카메라만을 이용하여 이족보행 로봇의 균형제어가 가능하다는 장점을 가지며, 소형이족로붓을 이용한 실험을 통해 그 효율성을 검증하였다.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1518-1520
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• 2008

Recent clinical studies have shown that computer navigation for total knee arthroplasty (TKA) provides improved component alignment accuracy. However, femoral stress fracture after computernavigated TKA have been reported due to the pin hole and we hypothesized that osteoporosis would be one of the key factors in pin hole fracture after computer-navigated TKA. We investigated the von-Mises stress around the femoral pin-hole for different elastic modulli and ultimate stresses and four different pin penetration modes to understand the aging effect on femoral stress fracture risk after computer-navigated TKA by finite element analysis. In this study, aging effect was shown to increase the femoral stress fracture risk for all pin penetration modes. Especially, aging effect was shown dramatically in the transcortical pin penetration mode.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.1
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• pp.7-14
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• 2021

In jewelry industry, the proportion of labor costs is high. Also, the production time and quality of products are highly varied depending on the workers' capabilities. Therefore, there is a demand from the jewelry industry for automation. The ear pin insertion automation system is the robot automatically inserts the ear pins into the silicone mold, and this automated system require accurate and fast hole detection method. In this paper, we propose optimal binarization method and a template matching method that can be applied in the ear pin insertion automation system. Through the performance test, it was shown that the applied method has an accuracy of 98.5% and 0.5 seconds faster processing speed than the Otsu binarization method. So, this automation system can contribute to cost reduction, work time reduction, and productivity improvement.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.711-717
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• 2010

In this paper, a new automatic punching system that generates pinholes expressing texts or images on a plastic plate is developed. The pin-holed plate is used as a new glamorous display board reflecting colourful lights from the light emitting diode (LED) installed on the edge side of the plate. The punching system has four actuators which work together to make multiple holes with accurate position and depth on the plastic plate. For even reflection of the lights from texts or images on the board and fast production of the pin-holed boards, we developed an accurate actuating structure of the system cooperating with a PID control algorithm. We also built a GUI-based integrated control system to help users easily design luminous texts or images on the plastic plate. Also, we conducted a performance test of the system to verify the punching speed and depth control of the pin holes on the plastic plate.

• Composites Research
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• v.23 no.3
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• pp.1-6
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• 2010

Recently, CFRP composite is more and more used in the various fields because of a higher specific modulus, chemical property and so on. Most products using CFRP composite are manufactured by construction of components. Various components are joined with those by bolts and pins. Holes for bolts and pins decrease strength and fatigue life of components, because those act as notch in structures. In this paper, we experimentally evaluated the fatigue life of hole-notched and unnotched weave CFRP plate. Then, we compared the two results and proposed an equation for prediction of fatigue life.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.566-566
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• 2012

그래핀(Graphene)은 모든 탄소 동소체의 기본구성 요소로 2 차원 결정구조를 가지며, 양자홀 효과(quantum Hall effect), 뛰어난 열 전도도, 고 탄성, 광학적 투과성 등과 같은 탁월한 물리적 성질을 보이는 물질이다. 이러한 그래핀의 우수한 특성은 전계 효과 트랜지스터(field effect transistor), 화학/바이오 센서, 투명 전극(transparent electrode) 등의 다양한 전자소자를 개발하는 응용 가능하다. 그 중, 그래핀 투명전극의 제조는 가장 응용가능성이 높은 분야이다. 현재 투명전극 물질로는 인듐-주석 산화물(indium tin oxide; ITO)가 널리 이용되고 있으나, 인듐의 고갈로 인한 공급부족 문제 및 고 생산비용, 휘어지지 않는 취성 등의 단점을 지니고 있다. 따라서, 우수한 광학적 투과성과 전기전도성을 지닌 그래핀이 ITO의 대체 물질로서 각광받고 있다.[1-5] 본 연구에서는 그래핀의 투명전도필름의 응용을 위해 면저항을 낮추기 위한 방법으로 화학적 도핑(doping)을 이용하였다. 그래핀은 구리(copper; Cu) 호일을 촉매로 사용하여 열 화학증착법(Thermal Chemical Vapor Deposition)을 이용하여 합성하였다. 합성된 그래핀은 PMMA(Poly(methyl methacrylate)) 전사법을 이용하여 산화실리콘(SiO2) 기판에 전사 후, 염화은(AgCl)과 클로로벤젠(C6H5Cl)으로 만든 콜로이드(colloid) 용액에 디핑(dipping)하여 그래핀에 은 입자를 도핑 하였다. 그 결과, 은 입자 도핑 농도에 따라 면저항이 감소하는 양상을 보였다. 제작된 그래핀 투명전도성 필름의 투과도는 자외선-가시광선-근적외선 분광법(UV-Vis-NIR spectroscopy)를 이용하여 측정하였고, 라만 분광법(Raman spectroscopy)을 통해 그래핀 필름의 질적 우수성과 성장 균일도를 조사하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.481-486
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• 2010

Recently, carbon fiber reinforced plastic (CFRP) have been used in various fields because of its high specific modulus, and chemical properties. Most products in which CFRP composites are used are manufactured by joining the product components by bolts or pins. Holes for bolts and pins decrease the strength of the components because these holes act as notches in the structures. In this study, the fracture strength of CFRP plain-weave composite plates containing holes is experimentally investigated to examine the effects of hole-size and specimen width on notched tensile strength. The results show that the characteristic length considered in the point stress criterion depends on the hole size and specimen width. There exists a certain relation between notched tensile strength and characteristic length. Fracture criterion is redefined on basis of this relation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1411-1417
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• 2010

CFRP (Carbon Fiber Reinforced Plastic) has received considerable attention in various fields as a structural material, because of its high specific strength, high specific stiffness, excellent design flexibility, favorable chemical properties, etc. Most products consisting of several parts are generally assembled by mechanical joining methods (using rivets, bolts, pins, etc.). Holes must be drilled in the parts to be joined, and the strength of the components subjected to static and fatigue loads caused by stress concentration must be decreased. In this study, we experimentally evaluated the variation in the residual strength of a holenotched CFRP plate subjected to fatigue load. We repeatedly subjected the hole-notched specimen to fatigue load for a certain number of cycles, and then we investigated the residual strength of the hole-notched specimen by performing the fracture test. From the results of the test, we can observe the initiation of a directional crack caused by the applied fatigue load. Further, we observed that the residual strength increases with a decrease in the notch effect due to this crack. It was evaluated that the residual strength increases to a certain level and subsequently decreases. This variation in the residual strength was represented by a simple equation by using a model of the decrease in residual strength for plain plate, which was developed by Reifsnider and a stress redistribution model for hole-notched plate, which was developed by Yip.