• 한국해양공학회지
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• 제33권1호
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• pp.98-98
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• 2019

• 대한조선학회논문집
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• 제56권1호
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• pp.11-22
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• 2019

In this paper, a Rankine source method is applied and validated to analyze the hydrodynamic response of a three-dimensional floating structure in the frequency domain. The boundary value problems for radiation and diffraction problem are solved by using a desingularized indirect boundary integral equation method (DIBIEM). The DIBIEM is simpler and faster than conventional methods based on the numerical surface integration of Green's function because the singularities of Green's function are located outside of fluid regions. In case of floating structure with complex geometry, it is difficult to desingularize the singularities of Green's function consistently. Therefore a mixed approach is carried out in this study. The mixed approach is partially desingularized except singularities of the body. Wave drift loads are calculated by the middle-field formulation method that is mathematically simple and has fast convergence. In order to validate the accuracy of the developed program, various numerical simulations are carried out and these results are analyzed and compared with previously published calculations and experiments.

• 대한조선학회논문집
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• 제42권2호
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• pp.113-123
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• 2005

A higher order panel method based on B-spline representation for both the geometry and the solution is developed for the analysis of steady flow around marine propellers. The self-influence functions due to the normal dipole and the source are desingularized through the quadratic transformation, and then shown to be evaluated using conventional numerical quadrature. By selecting a proper order for numerical quadrature, the accuracy of the present method can be increased to the machine limit. The far- and near-field influences are shown to be evaluated based on the same far-field approximation, but the near-field solution requires subdividing the panels into smaller subpanels continuously, which can be effectively implemented due to the B-spline representation of the geometry. A null pressure jump Kutta condition at the trailing edge is found to be effective in stabilizing the solution process and in predicting the correct solution. Numerical experiments indicate that the present method is robust and predicts the pressure distribution on the blade surface, including very close to the tip and trailing edge regions, with far fewer panels than existing low order panel methods.

• 한국해양공학회지
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• 제32권6호
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• pp.447-457
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• 2018

In this study, a two-dimensional fully nonlinear transient wave numerical tank was developed using a desingularized indirect boundary integral equation method. The desingularized indirect boundary integral equation method is simpler and faster than the conventional boundary element method because special treatment is not required to compute the boundary integral. Numerical simulations were carried out in the time domain using the fourth order Runge-Kutta method. A mixed Eulerian-Lagrangian approach was adapted to reconstruct the free surface at each time step. A numerical damping zone was used to minimize the reflective wave in the downstream region. The interpolating method of a Gaussian radial basis function-type artificial neural network was used to calculate the gradient of the free surface elevation without element connectivity. The desingularized indirect boundary integral equation using an isolated point source and radial basis function has no need for information about the element connectivity and is a meshless method that is numerically more flexible. In order to validate the accuracy of the numerical wave tank based on the desingularized indirect boundary integral equation method and meshless technique, several numerical simulations were carried out. First, a comparison with numerical results according to the type of desingularized source was carried out and confirmed that continuous line sources can be replaced by simply isolated sources. In addition, a propagation simulation of a $2^{nd}$-order Stokes wave was carried out and compared with an analytical solution. Finally, simulations of propagating waves in shallow water and propagating waves over a submerged bar were also carried and compared with published data.

• 한국식품위생안전성학회지
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• 제28권1호
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• pp.50-55
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• 2013

기름치를 참치회 또는 메로구이로 판매하는 사례가 있으며 국내에서는 2012년 6월1일부터 식품원료로 판매가 금지되어 이를 판별하는 시험법 마련이 필요하다. 기름치는 농어목(Perciformes) 갈치꼬치과(Gempylidae)에 속하는 기름갈치꼬치(R. pretiosus)와 흑갈치꼬치(L. flavobrunneum)가 있으며 이를 판별하기 위한 종 특이 프라이머를 개발하기 위하여 미토콘드리아에 존재하는 16S DNA 유전자부위를 선정하였다. 그리고 미국 국립보건원에서 운영하는 유전자 은행(www.ncbi.nlm.nih.gov)에 등록되어있는 기름갈치꼬치, 흑갈치꼬치. 참다랑어, 황다랑, 청새치 및 황새치의 염기서열을 대상으로 BioEdit ver. 7.0.9.0 프로그램을 사용하여 비교 및 분석을 실시하였다. 분석을 통하여 기름갈치꼬치 및 흑갈치꼬치를 판별할 수 있는 각각 4종의 프라이머를 설계하였다. 설계된 프라이머에 대하여 대조군으로 다랑어 3종(참다랑어, 황다랑어, 눈다랑어) 및 새치류 4종(청새치, 황새치, 녹새치, 돛새치)에 대한 실험적 평가를 실시하였다. 그 결과 기름갈치꼬치에 대하여는 R.P-16S-006-F/R.P-16S-008-R, 흑갈치꼬치는 L.F-16S-004-F/L.F-16S-006-R 프라이머를 최종 선정하였으며, PCR 조건을 확립하였다. 확립된 조건에서는 각각 178bp 및 238bp의 PCR 산물을 확인하였으며, 유사종간의 비특이적 밴드는 형성되지 않았다. 따라서 본 연구에서 개발된 기름치를 판별할 수 있는 종 특이 프라이머는 인터넷쇼핑몰 또는 시중에 불법적으로 유통 가능성이 있는 제품을 신속하고 과학적으로 판별할 수 있어 식품안전관리에 활용도가 매우 클 것으로 기대된다.