• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.348-351
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• 2007

This paper investigates the natural modes of moduled floating structure with module unit connector. As an example structure, a floating parking place($120m{\times}60m$) is considered. In the evaluation of natural modes, numerical equations are formulated by FEM(Finite Element Method) and the natural modes are solved by the subspace iteration method. By comparing results for various stiffness of module unit connector, the effect of stiffness of unit connector is examined.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.356-360
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• 2008

This paper investigates the natural modes of moduled floating structure with module unit connector. As an example structure, a floating parking place($120m\;{\times}\;60m$) is considered. In the evaluation of natural modes, numerical equations are formulated by FEM(finite element method) and the natural modes are solved by the subspace iteration method. By comparing results for various sizes of module unit, the effect of unit size is investigated. By comparing results for various stiffness of module unit connector, the effect of stiffness of unit connector is also examined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1173-1176
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• 2007

This paper investigates the natural modes and static reponses of modularized floating structure. As an example structure, a floating parking place$(120m{\times}60m)$ is considered. In the evaluation of natural modes and static responses, numerical equations are formulated by FEM(Finite Element Method) and the natural modes are solved by subspace iteration method. By comparing responses of structures of various sizes of module unit, the effect of unit size is also investigated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.10a
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• pp.16-21
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• 1990

Recently, the finite element method has been sucessfully extended to treat the rather couplet phenomena such as nonlinear buckling problems which are of considerable practical interest. In this study, a finite element program to evaluate the elasto-plastic buckling stress is developed. The Stowell's deformation theory for the plastic buckling of flat plates, which is in good agreement with experimental results, is used to evaluate bending stiffness matrix. A bifurcation analysis is performed to compute the elasto-plastic buckling stress. The subspace iteration method is employed to find the eigenvalues. The results are compared with corresponding enact solutions to the governing equations presented by Stowell and also with experimental data due to Pride. The developed program Is applied to obtain elastic and elasto-plastic buckling stresses for various loafing cases. The effect of different plate aspect ratio is also investigated.

• Korean Journal of Remote Sensing
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• v.33 no.5_1
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• pp.547-557
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• 2017

In this paper, a new spectral unmixing based target detection algorithm is proposed which adopted Iterative Error Analysis as a tool for extraction of background endmembers by using the target spectrum to be detected as initial endmember. In the presented method, the number of background endmembers is automatically decided during the IEA by stopping the iteration when the maximum change in abundance of the target is less than a given threshold value. The proposed algorithm does not have the dependence on the selection of image endmembers in the model-based approaches such as Orthogonal Subspace Projection and the target influence on the background statistics in the stochastic approaches such as Matched Filter. The experimental result with hyperspectral image data where various real and simulated targets are implanted shows that the proposed method is very effective for the detection of both rare and non-rare targets. It is expected that the proposed method can be effectively used for mineral detection and mapping as well as target object detection.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.560-565
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• 2007

Motivated by needs such as those in the aerospace industry, this paper demonstrates ability to significantly increase buckling loads of perforated composite laminated plates by synergizing FEM and a genetic optimization algorithm (GA). Plate geometry is discretized into specially-developed 3D degenerated eight-node shell isoparametric layered composite elements. General shell theory, involving incremental nonlinear finite element equilibrium equation, is employed. Fiber orientation within individual plies of each element is controlled independently by the genetic algorithm. Eigen buckling analysis is performed using the subspace iteration method. Available results demonstrate the approach is superior to more conventional methodologies such as modifying ply thickness or the stacking sequence of individual rectilinear plies having common fiber orientation through the plate.

• Computational Structural Engineering : An International Journal
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• v.1 no.1
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• pp.31-38
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• 2001

In the case of the non-proportionally damped system such as the soil-structure interaction system, the structural control system and composite structures, the eigenproblem with the damping matrix should be necessarily performed to obtain the exact dynamic response. However, most of the eigenvalue analysis methods such as the subspace iteration method and the Lanczos method may miss some eigenvalues in the required ones. Therefore, the eigenvalue analysis method must include a technique to check the missed eigenvalues to become the practical tools. In the case of the undamped or proportionally damped system the missed eigenvalues can easily be checked by using the well-known Sturm sequence property, while in the case of the non-proportionally damped system a checking technique has not been developed yet. In this paper, a technique of checking the missed eigenvalues for the eigenproblem with the damping matrix is proposed by applying the argument principle. To verify the effectiveness of the proposed method, two numerical examples are considered.