• Journal of the KSME
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• v.49 no.6
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• pp.54-57
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• 2009

이 글에서는 다중물리(Multyphysics) 해석에 대한 전반적인 사항들을 살펴보고 연성해석 분야에서 널리 사용되고 있는 COMSOL Multiphysics의 해석능력에 대하여 나타내고자 한다. 다중물리 해석이 필요한 이유와 적용분야, 해석 시 고려사항, 해석 방식 등에 대하여 전반적으로 소개하고자 한다.

• Journal of the KSME
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• v.53 no.5
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• pp.51-55
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• 2013

이 글에서는 단분자해석방법을 이용하는 3세대 DNA 시퀀싱에 나타나는 다중물리-다중스케일 유동에 대한 해석방법들을 소개하고, 관련된 예제로 탄소나노튜브을 통한 DNA를 포함한 전해질 유동의 최신결과들을 소개하고자 한다.

• Journal of IKEEE
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• v.20 no.1
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• pp.94-102
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• 2016

This paper proposes a new prediction method to reduce times and labor of repetitive multi-physics simulation. To achieve exact results from the whole simulation processes, complex modeling and huge amounts of time are required. Current multi-physics analysis focuses on the simulation method itself and the simulation environment to reduce times and labor. However this paper proposes an alternative way to reduce simulation times and labor by exploiting machine learning algorithm trained with data set from simulation results. Through comparing each machine learning algorithm, Gaussian Process Regression showed the best performance with under 100 training data and how similar results can be achieved through machine-learning without a complex simulation process. Given trained machine learning algorithm, it's possible to predict the result after changing some features of the simulation model just in a few second. This new method will be helpful to effectively reduce simulation times and labor because it can predict the results before more simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.397-398
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• 2009

본 논문에서는 증강현실 환경에서 다중 시스템의 물리 시뮬레이션을 위한 동기화 방법을 제안한다. 증강현실 시스템의 몰입감 증대를 위하여 가상 객체에 물리 법칙에 기반을 둔 실질적인 움직임을 부여하는 방법을 논하고 이를 네트워크로 확장하기 위하여 물리 기반 증강현실 환경의 동기화 방법을 연구하였다. 이러한 연구를 통하여 증강현실 어플리케이션의 몰입감 증대와 네트워크 게임에서의 증강현실 도입이라는 새로운 방향도 제시 할 수 있을 것이다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.323-329
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• 2013

This study attempts to simulate the structure of a woody leaf netted venation system by using topology optimization techniques. Based on finite element method (FEM) analysis of an incompressible fluid, a topology optimal design is applied to those woody leaf netted venation models. To solve the transverse shear locking problem of a thin plate caused by the Mindlin-Reissner plate model where a leaf netted venation is assumed to be a thin plate, a P1-nonconforming element and selective reduced integration are employed. Topology optimal design is applied to multiple physical domains. Combined with the Darcy-Stokes flow problems and extended to the optimal design of fluid channels, the multiple physical models of the flow system are analyzed and venation patterns of leafs are simulated. The calculated optimal shapes are compared with the natural shapes of woody leaf venation patterns. This interdisciplinary approach may improve our understanding of the leaf venation system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.81-86
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• 2016

In this paper, we present multi-channel authentication based security card design. Since this security card is written on the transparent paper, security information is extracted by overlaying the card with smartphone screen. This method removes the limitations of physical layout in previous security card and improves the security level. Furthermore, our security card is secure when our card is exposed to malicious users.

• Geophysics and Geophysical Exploration
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• v.12 no.4
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• pp.309-315
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• 2009

Integrated interpretation of multi-geophysical data has been continuously used in terms that it has provided more confident information than the result from single-geophysical data. Especially, geostatistical integration has its own superiority that it is possible to deal with spatial characteristics as well as physical properties of survey data and the process of integration is clear. This paper further extends the previous work of geostatistical inversion for integrated interpretation. In this paper, we propose a new way of dealing with the case that the multi-geophysical data do not share the measurement range. According to the geostatistical kriging, the closer between the measurement points, the smaller kriging variance we get, and vice versa. We used this spatial properties as a weighting value to the process of geostatistical inversion for the geophysical data integration. An objective way to integrate different kinds of geophysical data measured at different ranges is provided with this algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1438-1443
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• 2016

In this paper, we investigate the effect of multiple antennas at a relay node on the performance of physical-layer network coding (PNC) in the two-way relay channel (TWRC). We assume that two source nodes have a single antenna and the relay node has multiple antennas. We extend the conventional TWRC environment with a signle antenna at both relay and source nodes to the case of multiple antennas at the relay node. In particular, we consider two decoding strategies: separate decoding (SD) and direct decoding (DD). The SD decodes each packet from the two sources and performs the network coding with bit-wise exclusive OR (XOR) operation, while the DD decodes the network-coded packet from the two sources. Note that both decoding strategies are based on log-likelihood ratio (LLR) computation. It is shown that the bit error rate (BER) performance becomes significantly improved as the number of antennas at the relay node.

• Geophysics and Geophysical Exploration
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• v.5 no.2
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• pp.78-83
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• 2002

The finite element method combined with the sensitivity method is adopted for 2-dimensionl Fourier transform inversion. To improve the efficiency of inversion calculation, multi-resolution wavelet method is proposed., Theoretical data which is obtained from above method is shown to examine the proposed method. Theoretical model assumes that underground cavity is located in limestone area. In theoretical model, 16 current and potential electrodes are located to get theoretical data. It is shown that the about inversion method is very exact and useful calculation method, in case the larger model is very small such as under ground cavity.

• Geophysics and Geophysical Exploration
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• v.12 no.4
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• pp.289-298
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• 2009

Optimal data processing parameters were designed to attenuate multiples in seismic data acquired in the south-eastern area of the East Sea, in 2008. Bunch of multiples caused by shallow sea water depth were perceived periodically up to two way travel time of 1,750 ms at every 250 ms over seismic traces. We abbreviated sea bottom multiple as SBM, Peg-leg multiple as PLM, and free-surface multiple as FSM. To attenuate these multiples, seismic data processing flow was constructed including NMO, stack, minimum phase predictive deconvolution filter and wave equation multiple rejections (WEMR). Prevalent multiples were suppressed by predictive deconvolution and remaining multiples were attenuated by WEMR. We concluded that combining deconvolution with WEMR was effective to a seismic data of study area. Derived parameter can be applied to the seismic data processing on adjacent survey area.