• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.685-692
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• 2004

A stochastic approach has been presented for superplastic deformation of Ti-6Al-4V alloy, and probability functions are used to model the heterogeneous phase distributions. The experimentally observed spatial correlation functions are developed, and microstructural evolutions together with superplastic deformation behavior have been investigated by means of the two-point and three-point probability functions. The results have shown that the probability varies approximately linearly with separation distance, and deformation enhanced probability changes during the process. The stress-strain behavior with the evolutions of probability function can be correctly predicted by the model. The finite element implementation using Monte Carlo simulation associated with reconstructed microstructures shows that better agreement with experimental data of failure strain on the test specimen.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1205-1220
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• 2006

This study was conducted to develop the evaluation model which can analyse local agenda 21 comprehensively and systematically from the making process to the designed contents. The evaluation model was devised through the theoretical review of local agenda 21 and designing the evaluation system composed of evaluation domains, related indicators and scales. The evaluation system was carefully constructed based on planning theories and the discussion and agreement of specialists regarding local agenda 21. This model has three evaluation domains of process, content, and evaluation of implementation with different weighting values. Each domain contains large indicators, medium indicators and small indicators. Each indicator has different weighting value according to its importance. Basically, each small indicator was scored by 3 or 5 point scale. This evaluation system can not only analyse local agenda 21 quantitatively, but also find out good points, problems, and limits of various phases of planning and implementing local agenda 21.

• Journal of Information Technology Applications and Management
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• v.19 no.2
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• pp.135-147
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• 2012

Software architecture, as a blueprint for the system, should provide a robust foundation for design, implementation, and maintenance, for communication and documentation, and for reasoning about important system properties. Software architecture plays a central role during the whole software life-cycle. There are so diverse definitions of the software architecture, however, and there is no common agreement about what software architecture is. Examining 27 'published' definitions of software architecture, we synthesize an extensive model on the essential elements of software architecture, which consists of components, interaction among components, well-formed structure, reasons, and various perspectives. Further, we explore the possibility of unifying diverse software architecture definitions into a software architecture life-cycle model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.421-430
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• 2000

We apply the Rayleigh Ritz method to analyze multi-layered plates with residual stresses. The method is very simple, straight forward, and easily programmable, but it should be applied to structure s only in simple shapes. We derive coupled variational equations based on the principle of virtual displacement, and investigate what kind of basis functions is desirable for the analysis of rectangular plates with various boundary conditions. We demonstrate the effectiveness and usefulness of the method through several examples. The analysis results obtained with the method are in good agreement with those available in literature. A multi-layered MEMS plate example shows that the coupling effect should not be ignored and that residual stresses do influence the stiffness of the structure very much.

• Bulletin of the Korean Mathematical Society
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• v.55 no.3
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• pp.881-898
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• 2018

This article deals with implementation of a high-order finite difference scheme for numerical solution of the incompressible Navier-Stokes equations on curvilinear grids. The numerical scheme is based on pseudo-compressibility approach. A fifth-order upwind compact scheme is used to approximate the inviscid fluxes while the discretization of metric and viscous terms is accomplished using sixth-order central compact scheme. An implicit Euler method is used for discretization of the pseudo-time derivative to obtain the steady-state solution. The resulting block tridiagonal matrix system is solved by approximate factorization based alternating direction implicit scheme (AF-ADI) which consists of an alternate sweep in each direction for every pseudo-time step. The convergence and efficiency of the method are evaluated by solving some 2D benchmark problems. Finally, computed results are compared with numerical results in the literature and a good agreement is observed.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.242-244
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• 2011

최근 SOA와 클라우드 컴퓨팅 기반의 IT 서비스가 증가함에 따라 정보처리 분야에서 SLA(Service Level Agreement)가 주목을 받고 있다. 통상의 SLA는 종이에 자연언어로 표현되는 것이어서 SLA 체결, SLA 관리나 SLA 기반 정보처리의 자동화가 제한된다. 오늘날과 같은 SOA, 온 디맨드 서비스, 유틸리티 컴퓨팅, 클라우드 컴퓨팅 환경에서는 서비스를 통합 자동관리할 수 있는 기술이 필요하다. 본 논문에서는 능동문서 기반의 ASLM(Active Service Level Managenment)의 계약체결 사용자 인터페이스(UI: User Interface)를 구현하여 일반 문서의 경우와 비교하여 보았다. 그 결과 ASLM의 UI가 SLA 체결, SLA 유지보수 자동화, 그리고 사용자의 편의성에서 SLA 기반의 계약업무 처리에 보다 효과적임을 알 수 있었다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3299-3308
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• 1999

One of the most important prerequisites for a successful software process is the collaboration and software requirements negotiation of all stakeholders in the software development process. Remote users using computer networks can negotiate software requirements by computer supported system, and can share their informations. The goal of software requirements negotiation system is an integration of all win conditions and an agreement after resolution of conflicts. The existing systems need an exclusive system and must be dependent on specific platform and network. Users must have the knowledge of all stakeholder's status and use homogeneous collaborating applications. This paper presents the Web-based software requirements negotiation system for the purpose of resolution of the existing systems' problems. The Web-based software requirements negotiation system can be driven by WinWin Spiral model, and it is based on hybrid execution method. The proposed system is validated and tested on heterogeneous environments.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.5
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• pp.125-131
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• 1996

In this paper, we introduced the BQBPH method for making the grating of high efficiency which was improtant in implementing optical PS. The pattern of graing was obtianed by computer simulations using iterative method, and the diffraction efficeincy of designed grating was about 67% through BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency was 47%. We implemented the optical PS with the grating and showed that optical experimental output patterns were good agreement with PS output patterns and first order was main diffraction order.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.397-403
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• 2010

The Immersed boundary method(IBM) is one of CFD techniques which can simulate flow field around complex objectives using simple Cartesian grid system. In the previous studies the IBM has mostly been implemented to fractional step method based Navier-Stokes solvers. In these cases, pressure buildup near IB was found to occur when linear interpolation and stadard mass conservation is used and the interpolation scheme became complicated when higher order of interpolation is adopted. In this study, we implement the IBM to an incompressible Navier-Stokes solver which uses SIMPLE algorithm. Bi-linear and quadratic interpolation equations were formulated by using only geometric information of boundary to reconstruct velocities near IB. Flow around 2D circular cylinder at Re=40 and 100 was solved by using these formulations. It was found that the pressure buildup was not observed even when the bi-linear interpolation was adopted. The use of quadratic interpolation made the predicted aerodynamic forces in good agreement with those of previous studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.409-415
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• 2003

The purpose of this paper is to develop the 2-Dim Lagrangian Hydrocode for the analysis of large deformations of solids with implementation of the contact algorithm. First, th e governing equations are discretized into a system of algebraic equations. For more accurate and robust contact force computation. the defense node contact algorithm was adopted and implemented. For the verification of the code developed, two cases are carried out; the Taylor-Impact test and two bodies impact. The von -Mises criterion is implemented into the code with the Shock equation of state. The simulation results show a good agreement compared with the published experimental data and results from the commercial code. It is necessary to implement several material models and failure models for applications to different impact and penetration problems.