• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.32-38
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• 2019

The flying wing configuration with high sweep angles and rounded leading edge represent a complex flow of structures by the leading edge vortex. For control of the tailless flying wing configuration with unstable directional stability, flaperon is used. In this study, we conducted numerical simulations for a non-slender flying wing configuration with a rounded leading edge and analyzed the effect of the sideslip angle and flaperon. Through aerodynamic coefficient analysis, it was found that the effect of AoS on lift and drag coefficient was minimal and the side force and moment coefficient were markedly influenced by AoS. As the sideslip angle increased, the pitch break, which is related to the pitching moment coefficient, was delayed. Through stability analysis, the directional and lateral static stability of the flying wing configuration were increased by flaperon. Also, the structure and behavior of the leading edge vortex were analyzed by observing the contour of the pressure coefficient and the skin friction line.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.118-123
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• 2006

본 논문에서는 반몰입형 가상현실 시스템인 반응형 멀티미디어 시스템(RMS: Responsive Multimedia System)을 이용한 개인화된 스토리텔링 기법을 제안한다. 인간은 글, 그림, 영상 기술 등을 이용한 다양한 스토리텔링 기법을 개발해 왔으며, 가상 현실 기술을 통하여 기존의 멀티미디어보다 한차원 높은 수준의 스토리텔링을 가능하게 하였다. 제안된 스토리텔링 기법은 테이블 형태의 다감각 사용자 인터페이스, 사용자 정보 처리와 위치기반 이벤트를 결정하는 컨텍스트 인식 응용 모델 (vr-UCAM), 그리고 가상환경 네비게이션과 변화, 캐릭터의 애니메이션을 가능케 하는 가상공간 관리기로 구성된다. 제안된 스토리텔링 기법은 다감각 사용자 인터페이스를 통하여 직관적인 상호작용을 가능하게 한다. 그리고 컨텍스트 인식 응용 모델을 활용하여 사용자 개인정보를 스토리에 적용하여 개인화된 스토리가 전개될 수 있도록 한다. 그리고 가상 환경의 네비게이션, 가상 캐릭터, 날씨 및 환경의 변화 등을 조절하여 실감있게 스토리가 전개되도록 한다. 제안된 스토리텔링 환경을 검증하기 위해 운주사에 얽힌 설화를 기반으로 가상 운주사 체험 시스템을 구현하였다. 이를 통해, 반응형 멀티미디어 시스템을 이용한 스토리텔링의 가능성을 검증하였으며, 컨텍스트 인식 응용 모형을 활용한 개인화된 스토리텔링을 선보였다. 제안된 스토리텔링 기법은 문화교육, 에듀테인먼트, 예술 분야에 활용될 것으로 기대된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.395-402
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• 2019

In order to increse the stability of old caissons, the design and the construction are performed by installation of new caissons on the back of or on the front of old caissons. In this study, we use the eigenfunction expasnion method to analyze the characteristics of wave forces when new circular caissons are installed on the back of old caissons. The comparison of numerical results between eigenfunction expansion method and ANSYS AQWA is made and the wave force acting on each circular caisson is calculated by considering the wave-structure interaction effect.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.586-595
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• 2007

The analytic solution of wave scattering of monochromatic waves on a pile breakwater by an eigenfunction expansion method is extended to the case of directional irregular waves. The scattering wave spectrum and the force spectrum can be expressed from the reflection coefficient, transmission coefficient and the wave forces obtained from changing frequencies and incident angles in monochromatic waves. By numerical integration of 2-dimensional spectrum which is function of frequencies and incident angles, the representative values for the scattered waves and wave forces are obtained and the dependence of the transmission coefficients and wave forces on the directional distribution function, the principal wave direction, the submergence depth, and porosity is analyzed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2368-2375
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• 1992

The transition of turbulent kinetic energy(TKE) balance along the centerline of the flow unit, which is composed of straight-duct, contraction and free-jet, has been investigated by the hot-wire anemometry. It is found that the mean turbulent kinetic energy is balanced by the dissipation in the internal flow region ; by the production and the dissipation, through contraction ; and by the dissipation, in initial region(X〈8D) of free-jet. But in the developing region (8D〈X〈20D) it is balanced by all of the three(ie, diffusion, production and dissipation). Finally, in the downstream of free-jet, the mean TKE is balanced again by dissipation like as the beginning. The decay-laws along the centerline are checked in the region of free jet as well as in the straightduct. After the developing region of free-jet also exist the decay-laws, the exponent of the axial turbulence being bigger than of the radial.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2099-2106
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• 2006

In this paper, we addressed the node positioning method for minimizing the sensing energy consumption in wireless sensor networks with adjustable sensing ranges. It is necessary for minimizing the sensing energy consumption to minimize the overlapped sensing area by neighboring nodes. To find a optimal node position, we derived a optimal equations by using the overlapped areas, each node's radiuses and expended angles of opposite neighboring nodes. Based on it, we devised a new node positioning method, called as ASRC(Adjustable Sensing Ranges Control). Unlike existing condition based model, our proposed method was derived from mathematical formula, and we confirmed its validity of sensing energy consumption through simulations.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.2
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• pp.29-36
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• 1980

This paper presents a method for constructing multiple- valued switching functions based on Galois fields. First the constructing Inethod for single- variable switching functions is developers and the results are extended to multiple- variable functions. The fundalnental Inathelnatical properties used in this paper are. (1) The sum of all elements over CF of is zero. (2) The Product of nonzero elements over GF(N) is equal to e1 for Neven, and e1( ) for N odd. With these properties, a relatlvely simple constructing method is developed, and a process for determining the coefficients of the expanded forms of switching functions is also obtained without successive multiplication of the polynomials. Some examples are given to illustrate the method.

• Archives of design research
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• v.13 no.4
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• pp.145-154
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• 2000

Higher educational results might come from the rational method of curriculum operation. Therefore, every subject in the major course should be planned to response the specialty of students and the efficient method of education are still more needed in technical college, in which students have to get the specialty on the short period of education. Because each subject in the major course works as the close cause and result of educational goal to form the specialty of students, the achievement of educational results in each subject is an important studying part of the educators in technical college. This study is a case of the approaching method for the improvement of learning effect by the connection of subjects 'Space Design' and 'Computer Aided Design' in the Dept. of Industrial design. It is considered to achieve two subjects' educational goals by leading up the students' learning concentration from the comprehension and experience about the co-relationship of the two subjects. And it shows the results of this approaching method such as students could get the design technology of the two subjects, and they could have self-confidence to the managing of the design process and planning of the design works as well.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.12
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• pp.1825-1836
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• 2008

Many applications in computer graphics require complex and highly detailed models. However it is often desirable to use approximations in place of excessively detailed models in order to control the processing time. Thus, we aim to develop a notion of optimal matrix to simplify surface which can rapidly obtain the high quality 2D patterns flattening 3D surface as follows. Firstly, two 3D bodies are modeled based on existing Size Korea data. Secondly, each model is divided by shell and block for its pattern draft. Thirdly, each block is flattened by grid and bridge method. Finally, we selected the optimal matrix and demonstrated the efficiency and quality of the proposed method. This proposed approach accommodates surfaces with darts, which are commonly used in the clothing industry to reduce the deformation of surface forming and flattening. The resulting optimal matrix could be an initiation of standardization for pattern flattening. It is expected that this method could facilitate much better approximation in both efficiency and precision.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.73-79
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• 1994

본 연구는 관리한계설정을 위한 새로운 방법을 제시한다. 일반적 관리한계는 중심선(Central Line)과 표준편차(Standard Deviation)에 기인한다. 그러나 본 연구에서는 제품수명주기(PLC)의 각 단계상 발생되는 손익분기점(Break-even Point)과 한계이익곡선 특성을 통하여 탄력적 관리한계(Elastic Control Limit : ECL)를 구축하고자 하였다. 탄력적 관리한계와 한계이익곡선의 관계에서 중심선은 최대이익, $3{sigma}$한계는 최대이익점과 가장 근접해 있는 (상위/하위)손익분기점까지의 거리로 파악할 수 있다. 그리고 총 변동은 ｛상위손익분기점(UBEP) - 하위손익분기점(LBEP)｝으로 고려할 수 있다. 전개 과정으로서는 1. 각 제품별 수명주기(PLC)를 각 단계별로 구분한다. 2. 각 단계별 총이익곡선(TRC)과 총비용곡선(TCC)을 구한다. 3. 한계이익곡선상의 최대이익지점을 구한다. 이러한 연구는 제품성장단계별 평균과 분산의 변동을 동시에 고려하여 탄력적 관리가 가능하다는 장점이 있다. 나아가 마케팅과 소비자 행동의 분석으로 확대될 수 있다.