• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2245-2252
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• 2002

Design sensitivity analysis scheme is proposed in an elasto -plastic finite element method with explicit time integration using a direct differentiation method. The direct differentiation is concerned with large deformation, the elasto-plastic constitutive relation, shell elements with reduced integration and the contact scheme. The design sensitivities with respect to the process parameter are calculated with the direct analytical differentiation of the governing equation. The sensitivity results obtained from the present theory are compared with that obtained by the finite difference method in a class of sheet metal forming problems such as hemi-spherical stretching and cylindrical cup deep-drawing. The result shows good agreement with the finite difference method and demonstrates that the preposed sensitivity calculation scheme is a pplicable in the complicated sheet metal forming analysis and design.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1274-1279
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• 2003

In this paper, a new meshfree technique which improves the numerical integration accuracy is introduced. This new method called the Petrov-Galerkin natural element(PG-NE) is based on the Voronoi diagram and the Delaunay triangulation which is based on the same concept used for conventional natural element method called the Bubnov-Galerkin natural element(BG-NE). But, unlike BG-NE method, the test shape function is differently chosen from the trial shape function. The proposed technique ensures that the numerical integration error is remarkably reduced.

• Korean Journal of Construction Engineering and Management
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• v.18 no.3
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• pp.42-51
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• 2017

Measuring and evaluating project progress and performance are the key element of the construction project success. Construction progress is typically measured quantitatively by evaluating cost and time allocated to the project deliverable, and thus properly integrating cost and time is essential to the project management. This research was performed to propose an alternative methodology to integrate the cost and time and provide a framework for the progress measurement. The researchers developed a typical work process for the cost and schedule planning and also developed an alternative cost-schedule integration method by using progress integration units (PIU). A discipline of a construction phase served as a common level for WBS and CBS integration, so the PIUs'were defined under discipline. A case study project was selected to validate the developed methodology. The result showed the proposed method improved efficiency of cost and time integration. The result also showed the excluding material for the progress measurement purpose significantly reduced the bias of progress measurement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.396-401
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• 1997

Dynamic stability of cylindrical shells subjected to follower forces is analyzed in this paper. Motion of shells is formulated in curvilinear coordinates that is consistent with assumptions made in the Timoshenko beam and the Mindlin plate. Using the finite element method, the induced equations are reduced to an equation with finite degrees of freedom. The 9-node Lagrangian element is used, and reduced integration is used to avoid shear and membrane locking. The effects of thickness ratio on the dynamic stability of cylindrical shells are studied.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.853-865
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• 2013

Inflatable panels made of modern and new textile materials can be inflated at high pressure to have a high mechanical strength. This paper is based on the finite element method as a general solution to determine the characteristics of deformed inflatable panels at high pressure in various end and loading conditions. Proposed method is based on the construction of weak form of formulation and application of Reduced Integration Element method (RIE) to solve the numerical problem of shear locking. The numerical results are validated as an outcome of comparison with other published results.

• Journal of computational fluids engineering
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• v.19 no.4
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• pp.37-44
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• 2014

A detailed satellite panel thermal model composed of more than thousands nodes can not be directly integrated into a spacecraft thermal model due to its node size and the limitation of commercial satellite thermal analysis programs. For the integration of the panel into the satellite thermal model, a reduced thermal model having proper accuracy is required. A thermal model reduction method was developed and validated by using a geostationary satellite panel. The temperature differences of main components between the detailed and the reduced thermal model were less than $1^{\circ}C$ in steady state analysis. Also, the dynamic responses of the detailed and the reduced thermal model show very similar trends. Thus, the developed reduction method can be applicable to actual satellite thermal design and analysis with resonable accuracy and convenience.

• Journal of the Korean Mathematical Society
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• v.49 no.1
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• pp.99-112
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• 2012

This paper attempts to present a numerical method for solving optimal control problems. The method is based upon constructing the n-th degree Jacobi polynomials to approximate the control vector and use differentiation matrix to approximate derivative term in the state system. The system dynamics are then converted into system of algebraic equations and hence the optimal control problem is reduced to constrained optimization problem. Numerical examples illustrate the robustness, accuracy and efficiency of the proposed method.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.11-17
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• 2000

,An residual stress and out-of plane deformation produced by butt welding was analyzed by four kinds of 3D-FEM programs(Thermal El-P1 Analysis) developed by authors. The magnitude of deformation of perpendicular to the welding line generated by butt welding was large when the reduced integration method was used. This was because of removal of the locking phenomenon, which it was generally known that the stiffness of the shear component of out-of-plane was largely evaluated. And the magnitude of residual stress was analyzed by using the FEM program based on a large and small deformation theory was similar to that was analyzed by the redeced integration method.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.317-326
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• 1998

This paper describes a reduced finite element formulation for nonlinear transient heat transfer analysis based on Lanczos Algorithm. In the proposed reduced formulation all material nonlinearities of irradiation boundary element are included using the pseudo force method and numerical time integration of the reduced formulation is conducted by Galerkin method. The results of numerical examples demonstrate the applicability and the accuracy of the proposed method for the nonlinear transient heat transfer analysis.

• Health Policy and Management
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• v.5 no.1
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• pp.80-105
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• 1995

Assuming that we introduced integration of medical insurance society for self-employed, this study was conducted to examine effects and results after the integration and to research more effective method for integration. To assess effects and results of the finacial status of 266 insurance societies after intergration, the data were obtained from "The Medical Insurance Program for Self-Employeds Statistical Yearbook in 1992". The major finding are as follows : 1. Three alternative integration proposals were made. First alternative proposal was consisted of 232 medical insurance societies, second was 187, and third was 115. 2. As the results of average number of the insured per insurance societies of medical insurance program for self-employed every alternative proposal, first was 88, 119 persons, second was 108, 576, and third was 178, 967 from 76, 576 persons of present socienties. 3. It was true that the more average size of societies increased, the more average administration expenditure per 1, 000 insured reduced. 4. The average size of societies grew bigger, the rate of general expenditure to general revenue more improved. Also, the rate of benefits to contributions was changed for better. But if not to have had correct analysis and precise preparation for integration, effects and results of integration were always not optiized. 5. According to results of simple regression formulas, it was proved that the more the average size of societies was increased, the more result was advantaged. 6. The law of majority and the economy of scale were applied in this study, and it was necessary to analyze and assess effectiveness and efficiency of integration. Therefore, when the integration of medical insurance societies for self-employeds will be performed, it must be taken into consideration. Among three alternative proposals, third was showed more effective alternative than anothe, second was presented more ineffective result than present system. To achieve more effective and efficient integration of regional medical insurance societies throughout the result of the regression formula on present cost curve, it is necessary to operate well-integrated societies and to know appropriative countermeasures of present situation of each societies. Also, for integrating regional medical insurance societies, it is necessary to continue more deep research through practical model activity and to investigate the effective size and managed method of the societies.societies.