• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1998.09a
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• pp.100-105
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• 1998

해양구조물의 연직 원형파일에 작용하는 파력은 주로 항력과 관성력의 합으로 표시되는 Morison 식을 이용하여 결정하여 왔다. 그러나 Morison 식은 대칭형상을 유지하며 비교적 완만히 변화하는 파에 대해서 적용이 가능하다. 구조물 부재에 쇄파가 작용할 경우, 쇄파파력은 항력과 관성력에 추가하여 강한 충격쇄파력을 포함하게 된다. 본 연구는 임의 이차원 경사해빈에서 경계요소법을 적용하여 쇄파 내부점들의 수립자 속도 및 가속도를 계산하고, 이들을 이용하여 쇄파에 의한 쇄파파력을 계산하기 위한 모델기법을 수립한다.(중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.307-308
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• 2001

축제식 양식장 호지의 노령화를 방지하기 위해 수차를 이용하여 호지에 폭기 및 순환작용을 활성화하여 수질과 저질을 개선하는 방법이 널리 사용되고 있다. 본 연구에서는 이차원 수심적분 Reynolds 방정식을 지배방정식으로 하였고 이를 유한차분식으로 이산화한 수치모형(PDM)을 개발하였다. PDM은 수차 1대에 의한 유속발생에 적용하여 수차로부터 l0m 거리마다 층별 유속을 측정한 자료와 비교하여 검증하였다. (중략)

• Journal of Biosystems Engineering
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• v.15 no.3
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• pp.199-206
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• 1990

연구 I에서 수행한 소뇌모델 선형조합 신경망(CMLAN)의 분석 결과와 제안된 능률적 학습 알고리즘들에 의거하여 이차원 비선형 함수치의 출력 모의시험과 팔의 형태에 따라 두개의 목적치를 갖는 2 자유도 머니퓨레이터의 동작지령 산출 모의시험을 행하였다. 특히 2 자유도 머니퓨레이터의 경우, 작업공간에 적절한 입력네트의 변수를 선정하고 하나의 입력공간을 공유하는 두개의 세부 소뇌모델 선형조합 신경망을 서로 연결하는 구조로써 팔의 형태와 목적 지점에 따라 네트를 선정하는 구조를 갖도록 하였다. 제안한 학습 알고리즘의 성능 및 CMLAN의 학습에 따른 효과를 학습이득에 따라 컴퓨터로 모의시험하였으며 그 결과를 분석하였다. 잘 알려진 신경망인 BACK-PROPAGATION 다층(Multi-Layer) 신경망과 함수연결 신경망(Functional Link Net)을 이용한 모의시험 결과를 비교 분석하였다. CMLAN의 학습 능률성은 학습에 소요되는 컴퓨터의 cpu시간과 학습 중의시스템의 최대 편차와 RMS 편차의 변이도 및 최종 시스템 수렴치로서 나타내었다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.1120-1128
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• 1999

The model-based object recognition is defined as a graph matching process between model images and an input image. In this paper, a graph matching problem is modeled as a n optimization problems and a genetic algorithm is proposed to solve the problems. For this work, fitness function, data structured and genetic operators are developed The simulation results are shown that the proposed genetic algorithm can match feature points between model image and input image for recognition of partially occluded two-dimensional objects. The performance fo the proposed technique is compare with that of a neural network technique.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.58-63
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• 2007

본 논문은 현미경이나 카메라 영상 등의 실시간 영상을 이용한 변형체(deformable object)의 햅틱 렌더링을 구현하는 방법에 관한 것이다. 이는 저속으로 변형하는 물체의 영상정보를 실시간으로 추출하여, 그에 대한 영상처리를 통해 변형과 이동에 대한 위치 정보를 제공함으로써 이루어진다. 물체에 변형이 가해지면 카메라를 통해 컴퓨터로 그 영상이 전송되며 얻어진 영상은 스네이크 알고리즘의 영상처리 과정을 거쳐 이차원 모델 구현을 위한 위치정보를 제공한다. 이 가상모델에 대한 햅틱 렌더링을 구현하여 햅틱장치에 힘 피드백을 주게 되며, 안정적인 햅틱 렌더링의 구현을 위해 보간법(interpolation) 및 보외법(extrapolation)을 적용하여 모델과 햅틱장치간의 샘플링 문제를 해결한다. 그래픽 렌더링 또한 구현하여 조작의 용이함을 제공한다.

• Water for future
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• v.16 no.4
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• pp.221-236
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• 1983

In semi-enclosed shallow sea areas typified by the Yellow sea and the East China Sea, currents and sea surface variations are predominantly tidal. During the recent years two-dimensional numerical hydrodynamic model of the Yellow Sea and the East China Sea has been developed, based on the vertically-integrated equations of motion and continuity, capable of reproducing amplitudes and phases of the principal components of tides to satisfiable accuracy. As a subsequent development a three-dimensional hydrodynamical nymerical model covering the Yellow Sea and the East China Sea has been formulated to investigate the vertical distribution of horizontal tidal current and the response of the continented to investigate the vertical distribution of horizontal tidal current and the response of the continental shelf sea to steady uniform wind stress field imposed over the surface. Features of the M2 tidal current and the wind-induced three-dimensional current structure determined from the computation have been examined and discussed.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.12
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• pp.59-68
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• 1999

The timing characteristics of an ASIC are analyzed based on the propagation delays of each gate and interconnect wire. The gate delay can be modeled using the two-dimensional delay table whose index variables are the input transition time and the output load capacitance. The AWE technique can be adopted as an algorithm to compute the interconnect delay. Since these delays are affected by the interaction to the two-dimensional delay table and the AWE technique. A method to model this effect has been proposed through the effective capacitance and the gate driver model under the assumption of single driving gate. This paper presents a new technique to handle the multiple CMOS gates driving interconnect wire by extending previous approach. This technique has been implemented in C language and applied to several interconnect circuits driven by multiple CMOS gates. In most cases, we found a few tens of speed-up and only a few percents of errors in computing both of gate and interconnect delays, compared to SPICE.

• Journal of the Korean Magnetics Society
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• v.24 no.5
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• pp.152-159
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• 2014

Magnetic gear can transmit torque without any mechanical contact among rotational parts in rotating mechanical systems. Especially, magnetic gear using rare-earth PMs can be used in variety of industry application because of their great power efficiency. Thus, recent trend shows that magnetic gear can be replaced with common mechanical gear. This paper deals with comparison and torque analysis for magnetic gears with parallel and Halbach magnetization according to various design parameters. Using a two dimensional (2D) finite element (FE) analysis, suitable gear ratio is selected. We performed analysis for magnetically connected inner and outer torque with respect to various design parameters including thickness of inner and outer PM, steel pole angle, segments of Halbach array and magnetization pattern of inner and outer PMs. Finally, we can obtain improved design model having parallel and Halbach magnetization with larger torque, compared with an initial design model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.479-485
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• 2006

The double gate(DG) MOSFET is a promising candidate to further extend the CMOS scaling and provide better control of short channel effect(SCE). DGMOSFETs, having ultra thin undoped Si channel for SCEs control, ale being validated for sub-20nm scaling. A novel analytical transport model for the subthreshold mode of DGMOSFETs is proposed in this paper. The model enables analysis of short channel effect such as the subthreshold swing(SS), the threshold voltage roil-off$({\Delta}V_{th})$ and the drain induced barrier lowering(DIBL). The proposed model includes the effects of thermionic emission and quantum tunneling of carriers through the source-drain barrier. An approximative solution of the 2D Poisson equation is used for the distribution of electric potential, and Wentzel-Kramers-Brillouin approximation is used for the tunneling probability. The new model is used to investigate the subthreshold characteristics of a double gate MOSFET having the gate length in the nanometer range $(5-20{\sim}nm)$ with ultra thin gate oxide and channel thickness. The model is verified by comparing the subthreshold swing and the threshold voltage roll-off with 2D numerical simulations. The proposed model is used to design contours for gate length, channel thickness, and gate oxide thickness.

• Explosives and Blasting
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• v.23 no.1
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• pp.65-77
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• 2005

Reflecting the fact that there are increasing number of old high-story apartment structures in urban area, it is expected that the demand of blasting demolition will increase in the near future. It is of great important to make up for the insufficient empirical knowledge in blasting demolition through priori method such as computer simulation. Computer simulation of the blasting demolition involves complicated process. In the past domestic researches, two-dimensional bonded particle model was used to examine the overall demolition behavior of a five-story simple structure. It was observed that the two-dimensional simulation did not properly simulate the collapsing behavior of a structure mainly due to the reduced degree of freedom. In this study, three-dimensional simulation was tried. It consumed a great amount of calculation time, which limited the extent of the study. A few parameters, such as delay times, amount of charge at each hole, ball properties, were modified in order to check oui; their effect on the collapsing behavior. The differences were observed as expected but the collapsing behavior did not exactly coincide with the test blasting with a scaled model.