• 한국추진공학회지
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• 제2권3호
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• pp.1-9
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• 1998

풍력에너지는 자연의 에너지를 이용하므로써 환경문제와 경제적 측면에서 다른 대체 에너지보다 훨씬 유리하여 세계 여러 나라에서 각광을 받고 있다. 경제적인 이유로 풍력발전을 위한 회전날개가 대형화 되고 있으며, 경량화를 위해 복합재 구조등의 첨단 항공기술이 적용되고 있는 추세이다. 본 연구에서는 500㎾급 중형 풍력 발전시스템을 개발함에 있어, 적합한 공력 성능을 갖는 경량화 복합재 회전날개의 개선 설계를 수행하였다. 회전날개의 경량화를 위해 기 설계된 쉘-스파 구조물을 쉘-스파-샌드위치 구조물로 설계를 수정하였고, 배선형 해석을 통해서 경량화에 따른 대변형 문제를 검토하였으며, 파괴응력보다 낮은 상태에서 발생되는 국부좌굴에 의한 구조물의 안전성을 검토하였다. 또한, 허브의 금속재 삽입부분의 전단핀에 의한 핀 홀 주위의 응력해석을 수행하여 충분히 안전함을 확인하였고, 수정 설계된 구조물이 운용구간내에서 공진이 발생하지 않음을 확인하였다.

• 한국정밀공학회지
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• 제33권8호
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• pp.669-681
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• 2016

Mechanical designers often make mistakes that result in unwanted over-constraints, causing difficulty in assembly operations and residual stress due to interference among parts. This study is concerned with detection and elimination of over-constraints. Screw theory is a general method that is used for constraint analysis of an assembly and motion analysis of a mechanism. Mechanical assemblies with plane-plane, pin-hole, and pin-slot constraint pairs are analyzed using screw theory to illustrate its utility. As a real-world problem, a ball valve design is analyzed using the same method, and several unwanted over-constraints are detected. Elimination measures are proposed. Nominal dimensions of some parts are adjusted, and dimensions and tolerances of the pins and holes are modified using the virtual condition boundary concept. The revised design is free of over-constraints. General procedure for applying screw theory to constraint analysis is established and demonstrated; it will contribute to improving quality of assembly designs.

• 한국공간구조학회논문집
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• 제7권6호
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• pp.61-68
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• 2007

대공간구조에서 접합부의 신뢰도는 매우 중요하다. 접합부에 사용되는 고력볼트의 나사부 유효단면적은 축부단면적보다 작고 볼트 축부에 락핀용 구멍이 있기 때문에 볼트 나사부 또는 락핀용 구멍에 응력집중 현상이 발생하여 취성 파단이 발생할 우려가 높다. 특히 접합부는 직렬형 구조로 이루어져 있다. 따라서 접합부에서의 극한상황시 파괴유형은 필히 취성파괴를 피해야 하며 연성파손으로 유도해야 한다. 따라서 본 연구에서는 볼 조인트 접합부의 소성변형능력을 향상시키고 현장에서 발생할 수 있는 시공오차의 흡수가 가능하도록, 볼트의 나사부나 핀부의 취성파단 없이 소성변형능력 향상을 목표로 하였다. 에너지흡수형 볼트를 사용함으로써 소성변형능력이 향상된 스페이스 프레임의 접합상세를 제안하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.383-387
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• 2004

The Fuel Test Loop (FTL) consists of In-Pile Test Section (IPS) and Out-of-Pile System (OPS). The test condition in IPS such as pressure, temperature and quality of the main cooling water, can be controlled by the OPS. The FTL has been developed to be able to irradiate three pins to the core irradiation hole (IR1 hole) by considering for its utility and user's irradiation requirement. The IPS vessel assembly (IVA) consists of IPS head, outer pressure vessel, inner pressure vessel, inner assembly and test fuel carrier. The IVA is approximately 5.6 m long and fits within a 74 mm in diameter envelope over the full height of the chimney. Above the top of the chimney, the head of the IPS is enlarged to allow the closure flanges and pipe work connections. IVA was designed to test the CANDU and PWR nuclear fuel pin together. Specially, wished to minimize interference by nuclear fuel change in design and synthesize these items and shape design for IVA.

• KIEAE Journal
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• 제7권4호
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• pp.135-140
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• 2007

In this study we settled the trouble of the MgO board of existence by this research. We changed the wooden one of the main ingredient of a board to a perlite and a mineral particle in the aluminum hydroxide group and proceeded with a study to physical character and fire resistance efficiency improvement. The result yellowing phenomenon could be improved and it was possible to reduce size decrease of pin hole and the frequency of occurrence. We found out that the in case of absorbed amount added 5~8% corresponding to the weight decreases the acrylic group emulsion suddenly. So this product is improved with the bending strength and water-resistance. After behavior stop time measurement of a mouse for experiments was measured at the time of a gas harmful effect test, an improved MgO board appeared more highly for an average of 138 seconds compared with a board of existence.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(3)
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• pp.227-230
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• 2002

In this paper we concentrate on overall direction of the gaze based on a head pose for human computer interaction. To decide a gaze direction of user in a image, it is important to pick up facial feature exactly. For this, we binarize the input image and search two eyes and the mouth through the similarity of each block ( aspect ratio, size, and average gray value ) and geometric information of face at the binarized image. We create a imaginary plane on the line made by features of the real face and the pin hole of the camera to decide the head orientation. We call it the virtual facial plane. The position of a virtual facial plane is estimated through projected facial feature on the image plane. We find a gaze direction using the surface normal vector of the virtual facial plane. This study using popular PC camera will contribute practical usage of gaze tracking technology.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.785-790
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• 2000

The resonant frequency of a gas-filled cylindrical Helmholtz resonator in a liquid is obtained analytically. The equation of motion of the resonator is derived by using the condition of equilibrium of forces acting on the mass in the neck of the resonator. The reaction force on the upper side of the cylinder due to the acceleration of external fluid and sound radiation is obtained by using the analytical results for the baffled circular-piston problem. From the frequency response function of the resonator, a formula to predict the resonant frequency of the resonator is derived. It is shown that the resonant frequency of the Helmholtz resonator significantly decreases due to the cushioning effect of gas inside the cavity. Therefore, when a pressure transducer is to be installed in a pin-hole type mounting method, much care should be paid to remove the gas from the cavity.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 1999년도 추계공동학술대회 논문집:21세기지식경영과 정보기술
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• pp.493-505
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• 1999

줌렌즈 카메라 보정은 매우 중요하고 적어도 두 가지 면에서 어려운 문제이다. 첫 번째는 실시간의 변화에 따라 카메라 내부 파라미터의 보정이고 두번째는 단일 렌즈 시스템의 핀홀모델은 줌렌즈시스템이 바로 적용하기가 어렵다. 그래서 이 논문에서는 이러한 문제의 일부분을 렌즈의 굴절현상, 초점 거리의 보정과 모델링, 확대에 관한 중요한 원리들뿐만 아니라 실제적으로 유용한 부분들을 기술하였다. 컴퓨터에 의해 제어되는 줌, 초점, 그리고 구경들의 실험결과가 제시되어있다.

• 센서학회지
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• 제17권4호
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• pp.273-280
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• 2008

Monolith aperture-type oxygen sensors with simple structure of YSZ(pin-hole)/Pt/ YSZ(solid electrolyte)/Pt were fabricated by co-firing technique. To enhance the yield of productivity, a couple of YSZ green sheets for diffused barrier and solid electrolyte were prepared by tape-casting and co-firing method. The limit current characteristics of the oxygen sensors were measured between 500 and $650^{\circ}C$ The heating temperature of $600^{\circ}C$ was optimum as a portable oxygen sensor in the range of oxygen concentration from 0 to 75 vol%. Linear proficiency of limit current behavior as a function of oxygen concentration was controlled by the variation of aperture dimension. The fabricated oxygen sensors showed the stable sensing output for 30 days. Gas leakage in bonding area due to warping, cracking and thermal cycling was not found in the period.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.76-77
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• 2014

Stone is one of the oldest and most popular materials used on the external wall because of its durability, abundance and aesthetic effect. However, there are two main problems in the existing pin hole construction method. One is uniformity of construction quality, and the other is a repair work of stone panels. Therefore, a new method is needed to overcome these problems. This paper presents a new stone curtain wall system using under cut anchor and secondary holes that was developed by authors. The improved quality and reduction of construction period can be obtained by this system.