• Journal of the Society of Naval Architects of Korea
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• v.31 no.1
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• pp.14-21
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• 1994

The studios on the stability of damaged ships have been carried out continuously to prevent frequent damages or sinkings which cause large loss of life and fortunes. For dry cargo ships, continuing losses have resulted in new legislation of the probabilistic damage stability. IMO has developed requirements for the subdivison and damage stability of dry cargo ships based on probabilistic concepts. The calculation of the probabilistc damage stability is a complicated and iterative job hence development of computer programs is indispensable. In this research, programming of the probabilistic damage stability according to new requirements has been done and the results were compared with those carried out by the other foreign packages. New algorithm using a grid model in a transversal section was introduced to reduce efforts in preparing input data for damage scenarios and as a result, has brought significant improvement in efficiency and performance.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.627-630
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• 2002

In the present study a mesh generation program is developed for the flow analysis of industrial mixers. With this program one can select various design parameters such as impeller types, vessel type, number of baffles, number of blades, blade pitched angle, stages of impeller, rotational speed etc. Post processing capabilities are also imbedded in the program. Along with brief explanation of the program, examples of flow simulation for various type of mixers by using the program are also presented to show effectiveness of the program. It is expected that this program can be used to understand the effect of design parameters on the performance of particular type of the mixer, and hence to achieve the optimal design.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.92-100
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• 2002

In this study, transonic/supersonic nonlinear flutter analysis system of a complete aircraft including forced harmonic motion pf control surfaces has been effectively developed using the modified transonic small disturbance (TSD) equation. To consider the nonlinear effects, the coupled time marching method (CTM) combining computational structural dynamics (CFD) has been directly applied for aeroelastic computations. The grid system for a complex full aircraft configuration is effectively generated by the developed inhouse code. Intransonic and supersonic flight regimes, the characteristics of static and dynamic aeroelastic effect has been investigated for a complete aircraft model. Also, nonlinear flutter flight simulations for the forced harmonic motion of control surfaces are practically presented in detail.

• Journal of the Korean earth science society
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• v.38 no.1
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• pp.80-90
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• 2017

To build tetrahedra mesh for FEM numerical analysis, Boundary Representation (B-Rep) model is required, which provides the efficient volume description of an object. In engineering, the parametric solid modeling method is used for building B-Rep model. However, a geological modeling generally adopts discrete modeling based on the triangulated surface, called a Sealed Geological Model, which defines geological domain by using geological interfaces such as horizons, faults, intrusives and modeling boundaries. Discrete B-Rep model is incompatible with mesh generation softwares in engineering because of discrepancies between discrete and parametric technique. In this research we have developed a converting program from Sealed Geological Model to Gmsh and COMSOL software. The developed program can convert complex geological model built by geomodeling software to user-friendly FEM software and it can be applied to geoscience simulation such as geothermal, mechanical rock simulation etc.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.275-283
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• 2013

In this paper, the structural optimum design method of composite rotor blade cross-section was investigated with the genetic algorithm. An auto-mesh generation program was developed for iterative calculations of optimum design, and stresses in the blade cross-section were analyzed by VABS (variational asymptotic beam sectional analysis) program. Minimum mass of rotor blade was defined as an object function, and stress failure index, center mass and blade minimum mass per unit length were chosen as constraints. Finally, design parameters such as the thickness and layup angles of a skin, and the thickness, position and width of a torsion box were determined through the structural optimum design method of composite rotor blade cross-section presented in this paper.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.65-70
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• 2009

In this paper a hybrid grid generation program for general 2-D region is introduced. The program is developed by using JAVA programming language, and it can be used either as an application program on a local computer or as an applet in the network environment. The hybrid grid system for a 2-D problem means a combination of triangular cells and quadrilateral cells, and it can offer both of the high flexibility of triangular cells and the high accuracy and efficiency of structured-type quadrilateral cells. To accommodate a quadrilateral-cell region and a triangular-cell region into one computational domain, it is importance to take good care of the interface between two different regions so that overall good grid quality can be maintained. In this research advancing layer method(ALM) augmented by elliptic smoothing method is used for the quadrilateral-cell region and advancing front method(AFM) is used for the triangular-cell region. A special treatment technique for the interface between those two regions is also developed. The interface treatment technique is basically to prevent the propagation of small cell size due to ALM method into the triangular region and maintain the smooth transition of cell-size scale between two different regions. By applying current technique high-quality hybrid grids for general 2-D regions can be easily generated, and typical grid generation results and flow solutions are demonstrated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.400-403
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• 2009

본 연구에서는 평판 스페이스 프레임 구조물의 크기 및 형상최적화 기법을 개발하고자 한다. 이를 위해 평판 스페이스 프레임의 물량에 영향을 미치는 요소인 격자분할 수와 상 하부 평판사이의 높이를 주요 설계변수로 선정함으로써 부재크기 최적화뿐만 아니라 형상최적화 방안도 제시하였다. 또한 평판 스페이스 프레임의 절점 및 부재 자동생성방안이 고려되며 감도해석기법을 이용하여 개발된 최적화 프로그램을 예제모델에 적용하여 설계변수 변화에 따른 구조시스템의 최적의 대안을 강구하고자 한다.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1407-1417
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• 1996

In recent researches on thread partitioning algorithms break a thread at the long latency operation and merge threads to get the longer threads under the given constraints. Due to this limitation, even a program with little parallelism is partitioned into small-sized threads and context-swithings occur frequently. In the paper, we propose another method array localization about the array name, dependence distance(the difference of accessed element index from loop index), and the element usage that indicates whether element is used or defined. Using this information we can allocate array elements to the node where the corresponding loop activation is executed. By array localization, remote accesses to array elements can be replaced with local accesses to localized array elements. As a resuit,the boundaries of some threads are removed, programs can be partitioned into the larger threads and the number of context switchings reduced.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.514-526
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• 2004

Microarray is a new technique for gene expression experiment, which has gained biologist's attention for recent years. This technology enables us to obtain hundreds and thousands of expression of gene or genotype at once using microarray Since it requires manual work to analyze patterns of gene expression, we want to develop an effective and automated tools to analyze microarray image. However it is difficult to analyze DNA chip images automatically due to several problems such as the variation of spot position, the irregularity of spot shape and size, and sample contamination. Especially, one of the most difficult problems in microarray analysis is the block and spot addressing, which is performed by manual or semi automated work in all the commercial tools. In this paper we propose a new algorithm to address the position of spot and block using a new concept of regular structure grid searching. In our algorithm, first we construct maximal I-regular sequences from the set of input points. Secondly we calculate the rotational angle and unit distance. Finally, we construct I-regularity graph by allowing pseudo points and then we compute the spot/block address using this graph. Experiment results showed that our algorithm is highly robust and reliable. Supplement information is available on http://jade.cs.pusan.ac.kr/~autogrid.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.1-7
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• 2013

In this paper the developed prediction technique of wave-making resistance performance for a ship attached with a vertical blade had been verified. Numerical analysis program as a prediction technique had been developed using the Rankine source panel method and the vortex lattice method(VLM). The nonlinearity of the free surface conditions was fully taken into account using the iterative method and the trim and the sinkage of the ship were also considered in the numerical analysis program. Panel cutting method was applied to get hull surface panels. Numerical computations were carried out for a 4000TEU container carrier and the vertical blade was attached 6 different locations astern. To investigate the validity of the numerical analysis program the commercial viscous flow field analysis program FLUENT was used to obtain the viscous flow field around the ship and the model test was performed. The model test results were compared with the numerical analysis results.