• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.435-443
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• 2015

Offshore structure may be considerably vulnerable to fatigue failure while initial flaw propagates under cyclic loading, so crack propagation analysis/fracture/yield assessments about initial flaw detected by NDT are necessarily required. In this paper, case studies have been conducted by flaw assessment program using engineering criticality analysis (ECA) approach. Variables such as flaw geometry, flaw size, structure geometry, dynamic stress, static stress, toughness, crack growth rate, stress concentration factor (SCF) affected by weld are considered as analysis conditions. As a result, the safety of structure was examined during fatigue loading life. Also, critical initial flaw size was calculated by sensitivity module in the developed program. The flaw assessments analysis using ECA approach can be very useful in offshore industries owing to the increasing demand on the engineering criticality analysis of potential initial flaws.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.4
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• pp.49-60
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• 1999

In this paper we introduce the definition and historical overviews of computer virus program and review their side-effect and ways of infections. We describe the feature of CIH virus which damaged lots of PC systems in Asian countries recently and propose new methods how to rescue against destruction under the operating system of the Microsoft's Windows 95/98. Our experiment results can fix hard disk having FAT32 file system structure and show some popular program cases of having recovered by commercial vaccine program.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.261-266
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• 1998

In this study, crush characteristics of thin-walled rectangular tube is investigated. The stiffness of the element is obtained from analytical moment-rotation relationship and approximated load-deflection relationship of thin-walled rectangular tube. A computer program is developed for the large deformation analysis of frame. An incremental displacement method is used in the program and at each incremental stage, the stiffness matrix of the total structure is checked with the state each element for bending and compression.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1396-1401
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• 2004

In recent years, robot has been used widely in industrial field and has been expanded as a result of continous research and development for high-speed and miniaturization. The goal of this paper is to design the special serial manipulator through the understanding of the structure, mobility, and analysis of serial manipulator. Thereafter we control the position and orientation of end-effector with respect to time. In general, a structure of industrial robot consists of several links connected in series by various types of joints. Typically revolute and prismatic joints. The movement of these joints is determined in inverse kinematic analysis. Compared to the complicated structure of parallel and hybrid robot, open loop system retains the characteristic that each link is independent and is controlled easily by AC servomotor that is used to place the robot end-effector toward the accurate point with the desired speed and power while it is operated by position control algorithm. The robot end-effector should trace the given trajectory within the appropriate time. The trajectory of 3D end-effector model made by OpenGL can be displayed on the monitor program simultaneously

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.103-114
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• 2003

This paper aims to propose a method that helps maintenance engineers to evaluate the damage states of bridge structure systems by using a Fuzzy Fault Tree Analysis. It may be stated that Fuzzy Fault Tree Analysis may be very useful for the systematic and rational fuzzy reliability assessment for real bridge structure systems problems because the approach is able to effectively deal with all the related bridge structural element damages in terms of the linguistic variables that incorporate systematically experts experiences and subjective judgement. This paper considers these uncertainties by providing a fuzzy reliability-based framework and shows that the identification of the optimum maintenance scenario is a straightforward process. This is achieved by using a computer program for LIFETIME. This program can consider the effects of various types of actions on the fuzzy reliability index profile of a deteriorating structures. Only the effect of maintenance interventions is considered in this study. However. any environmental or mechanical action affecting the fuzzy reliability index profile can be considered in LIFETIME. Numerical examples of deteriorating bridges are presented to illustrate the capability of the proposed approach. Further development and implementation of this approach are recommended for future research.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.567-568
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• 2009

The CAMUS 2000-1 experimental program were performed in France to investigate of the 1/3-scaled reinforced concrete bearing walls behavior on the shaking table under biaxial earthquake loading. The nonlinear 3D finite element analysis of push over test and linear dynamic analysis under biaxial earthquake loading are investigated with the concrete damaged plasticity model using ABAQUS.

• Structural Engineering and Mechanics
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• v.20 no.4
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• pp.389-403
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• 2005

In the present paper it is aimed to perform the stochastic dynamic analysis of fluid and fluidstructure systems by using the Lagrangian approach. For that reason, variable-number-nodes twodimensional isoparametric fluid finite elements are programmed in Fortran language by the authors and incorporated into a general-purpose computer program for stochastic dynamic analysis of structure systems, STOCAL. Formulation of the fluid elements includes the effects of compressible wave propagation and surface sloshing motion. For numerical example a rigid fluid tank and a dam-reservoir interaction system are selected and modeled by finite element method. Results obtained from the modal analysis are compared with the results of the analytical and numerical solutions. The Pacoima Dam record S16E component recorded during the San Fernando Earthquake in 1971 is used as a ground motion. The mean of maximum values of displacements and hydrodynamic pressures are compared with the deterministic analysis results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.439-445
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• 2013

The soil-structure interaction(SSI) effect should be considered to accurately assess the seismic response of structure constructed on soft soil site other than the hard bedrock. Recently, the demand of SSI analysis has increased due to strengthening of the regulatory guidelines of nuclear power plant such as the USNRC SRP 3.7.2. In this study an accuracy and running time of the KIESSI-3D program for large-scale 3D SSI analysis were investigated. The seismic SSI analysis using the KIESSI-3D program was performed for several examples of large-scale three-dimensional soil-structure interaction system. The analysis results were compared with those of the ACS/SASSI program. Good agreements in transfer functions at selected locations showd that KIESSI-3D yields accurate solution for large-scale SSI problem. Moreover, it was found that running speed of the KIESSI-3D for large-scale 3D SSI analysis is much faster than that of the ACS/SASSI about 30~2000 times.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.887-901
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• 2002

Software management model divided into the software project model and design estimation model, software matrices model, reliability growth model, process improvement model(or process maturity model) etc. Among these software management models, software complexity model make an estimated of the product software. For a practice of software managed, need to guideline of the static analysis of software. Especially, Software complexity model introduced for the estimation of software quantity and program complexity. In case of measurement the software matrices, its need for us to analysis of software quality and products. On the other hand, we known that complexity program include many defects and consuming of source cost. So, we apply to complexity model using of the program complexity, control structure and volume matrices, interface metrics, process complexity metrics method. In this paper, we represent that the analysis of fault data detected during the system test. Also, we analysis of program control structure and interface, volume matrices in various aspect of switching software. Others, their results utilized similar of project and system development.

• Steel and Composite Structures
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• v.26 no.2
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• pp.163-170
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• 2018

The purpose of this paper is to present a new and efficient optimization algorithm called Jaya for optimum design of steel grillage structure. Constrained size optimization of this type of structure based on the LRFD-AISC is carried out with integer design variables by using cross-sectional area of W-shapes. The objective function of the problem is to find minimum weight of the grillage structure. The maximum stress ratio and the maximum displacement in the inner point of steel grillage structure are taken as the constraint for this optimization problem. To calculate the moment and shear force of the each member and calculate the joint displacement, the finite elements analysis is used. The developed computer program for the analysis and design of grillage structure and the optimization algorithm for Jaya are coded in MATLAB. The results obtained from this study are compared with the previous works for grillage structure. The results show that the Jaya algorithm presented in this study can be effectively used in the optimal design of grillage structures.