• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.398-409
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• 2010

This paper considers the numerical computation of added resistance on ships in the presence of incident waves. As a method of solution, a higher-order Rankine panel method is applied in time domain. The added resistance is evaluated by integrating the second-order pressure on the body surface. Computational results are validated by comparing with experimental data and other computational results on a hemi-sphere, a barge, Wigley hull models, and Series 60 hull, showing very fair agreements. The study is extended to the comparison between Neumann-Kelvin and double-body linearization approaches, and their differences are discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1808-1817
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• 1994

Unsteady aerodynamic analysis of an aircraft is done using a frequency domian 3-D panel method. The method is based on an unsteady linear compressible lifting surface theory. The lifting surface is placed in a flight patch, and angle of attack and camber effects are implemented in upwash. Fuselage effects are not considered. The unsteady solutions of the code are validated by comparing with the solutions of a hybrid doublet lattice-doublet point method and a doublet point method for various wing configurations at subsonic and supersonic flow conditions. The calculated results of dynamic stability derivatives for aircraft are shown without comparision due to lack of available measured data or calculated results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1590-1597
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• 1994

The aerodynamic analysis of a $6{\times}6$ counter-rotating propfan around a missile-like-body has been completed analytically using a frequency domain panel method. The present method requires Fourier transformation of flow field around the propfan in computing the velocities normal to the propfan lifting surfaces. The aerodynamic performance curve is determined by angle of attack and nonuniform inflow conditions. The inflow conditions result from the variations of missile flight speed, angle of attack, propfan location relative to control surfaces and control surface deflection angle. The two cases of propfan location relative to control surface, front and behind, are analyzed and the aerodynamic results are presented.

• Survey Research
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• v.7 no.2
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• pp.97-122
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• 2006

Korean Longitudinal Study of Ageing(KLoSA)', launched in 2006, has developed a research network with 'Health and Retirement Study(HRS, US),' Studies on Health and Retirement in Europe(SHARE, EU),' and 'English Longitudinal Study of Ageing(ELSA, UK)'and tried to construct a mega data library. The KLoSA team has designed their research with focusing on the following three points, in order to use KLoSA for international comparative studies. First, KLoSA shares the key research areas such as family structure, health, employment, income, asset, subjective expectations with the comparable studies. Second, KLoSA team has developed the instrument to reflect the Korean culture and institutions. They considered the institutional characteristics in public pension and health care system and in employment practices. They also counted the cultural conventions in family life such as financial management and care exchange, Finally, KLoSA tries to capture the psychological characteristics of the Korean elderly by making the measurement scales more understandable.

• Journal of Korean Society of Steel Construction
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• v.25 no.2
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• pp.141-151
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• 2013

In this paper, lateral-torsional buckling(LTB) strength of HSB800 steel plate girder under uniform bending moment was estimated by the nonlinear analysis. Doubly symmetric sections with slender, noncompact and compact webs were considered and the LTB strength in the inelastic range was estimated by taking initial imperfection and residual stress into account. For the numerical analysis, single-panel model and three-panel model were considered and analysis of SM490 steel plate girder was performed to judge the validity of the constructed models by comparing the results with AASHTO, AISC, Eurocode and KHBDC(LSD) codes. By using the same models, LTB strength of HSB800 girder was evaluated and it was acknowledged that the current codes can be applied to HSB800 girders with doubly symmetric section in the inelastic LTB range.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.10
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• pp.955-965
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• 2010

The MH-75 propeller for the MAV propulsion is designed using a free vortex design method which considers design parameters such as the hub-tip ratio, the twist angle distribution, the maximum camber location and the chord length of the propeller blade. Aerodynamic characteristics of the MH-75 propeller are predicted by changing the flight speed using the frequency domain panel method. And, the thrust characteristics of the MH-75 propeller are measured using the balance system of the subsonic wind tunnel for the validation of numerical results. The performance characteristics of the MH-75 propeller satisfied with design requirements. Numerical results of the MH-75, which are predicted by the frequency domain panel method, are more agree with experimental results compare with XFOIL.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.1-11
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• 2004

Numerical analyses on the aerodynamic characteristics of a counter rotating axial flow fan were conducted for the development of an axial type in-line duct fan. The counter rotating fan has a front rotor and a rear rotor which are counter rotating each other. Blade design of the counter rotating fan was done by extension of design method for axial flow fan which consists of rotor and stator blades. Through flow analysis was performed using matrix method which is applied for flow fields prediction of compressors or turbines. Aerodynamic characteristics and characteristic curves of the counter rotating fan were analyzed by expansion of the frequency domain panel method with duct modeling. Pressure losses were higher at leading edge and hub region of rotor blades. Characteristic curve of the counter rotating fan was overpredicted without consideration of viscous effect.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.37-38
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• 2009

터치스크린 기능이 있는 LCD 패널이 부착된 임베디드 시스템의 경우, 사용자 입력 명령의 전달을 위해 사각형, 오각형, 원, 화살표 같은 다양한 도형들이 자주 사용된다. 이 경우, 특정 명령 입력 여부의 판단을 위해 터치된 지점이 그 명령을 의미하는 도형 내에 있는지의 여부를 판단하는 알고리즘이 필요하다. 그러나 이런 알고리즘들은 제한된 컴퓨팅 자원을 갖는 임베디드 시스템의 경우 상당한 오버헤드를 유발 할 수 있다. 본 논문은 도형 영역의 터치 여부의 판단을 위해 사용 되고 있는 사각형의 범위 검사법, 다각형의 교차 수(crossing number) 검사법, 원의 거리 측정법, 그리고 이런 모든 도형들에 적용 가능한 색상 비교법을 구현하고, 성능 평가를 위해 각 방법에 따라 사각형, 오각형, 원, 그림 같은 도형들의 영역 터치 여부를 판단하는데 걸리는 시간을 측정한다. 이 측정 결과, 사각형은 범위 검사법이, 원은 거리 측정법이, 다각형 및 그림을 이용한 도형일 경우에는 색상 비교법이 가장 적합한 것으로 나타났다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.293-308
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• 1999

이 논문에서는 패널, 깊은 보 그리고 전단벽과 같이 평면응력상태하에 있는 철근콘크리트 구조물의 비선형 유한요소해석에 있어서의 직교이방성 콘크리트 구성 모델의 적용성을 보여준다. 등가의 일축 변형을 개념을 토대로 콘크리트의 구성 관계가 주변형률 축과 일치하고 하중이력에 따라 회전하는 직교하는 축에 대해 제시된다. 제안된 모델은 이축 압축응력상태와 인장-압축 응력상태에서 각각 압축강도의 증가와 인장 저항력의 감소효과를 보여주는 이축 파괴영역의 정의를 포함한다. 인장균열이 발생한 후, 콘크리트의 압축강도의 감소효과가 제시되고, 인장강화효과로 알려진 철근에 의해 지지되는 콘크리트의 인장응력이 고려된다. 평균응력과 평균변형률 개념을 사용하여 힘의 평형, 적합조건 그리고 철근과 철근을 둘러싼 콘크리트 사이의 부착응력-슬림 관계를 토대로 인장강화효과를 모사하기 위한 모델이 제안된다. 유한요소 모델에 의한 예측은 유용한 실험자료와의 비교에 의해 입증된다. 이 논문에서는 해석결과와 이상화한 전단 패널실험으로부터 얻어진 실험값의 비교연구가 수행되고, 제안된 모델의 타당성을 보여주기 위해 서로 다른 응력상태하의 전단 패널 보와 벽체의 힘-변위 관계를 평가하였다.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.456-458
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• 2008

RV 차량의 쿠션 패널을 생산하여 조립하는 공정은 작업자의 오류로 인한 불량이 많이 발생된다. 본 연구에서는 이러한 불량을 제거하기 위한 화상검사장치를 개발함을 목적으로 한다. 이러한 장치개발은 쿠션패널 고정용 지그, 카메라 인식영역, 이송을 위한 X-Y테이블, 카메라 모듈, 제어기 로 구성되어진다. 본 논문에서 제안한 화상검사장치를 설계하고 화상인식 프로그램을 통해 불량을 판정하여 화상검사 시스템의 타당성을 검증하였다.