• Journal of computational fluids engineering
• /
• v.12 no.1
• /
• pp.43-52
• /
• 2007

A comparative study on flux functions for the 2-dimensional Euler equations has been conducted. Explicit 4-stage Runge-Kutta method is used to integrate the equations. Flux functions used in the study are Steger-Warming's, van Leer's, Godunov's, Osher's(physical order and natural order), Roe's, HLLE, AUSM, AUSM+, AUSMPW+ and M-AUSMPW+. The performance of MUSCL limiters and MLP limiters in conjunction with flux functions are compared extensively for steady and unsteady problems.

• 한국디지털정책학회:학술대회논문집
• /
• 2005.06a
• /
• pp.591-604
• /
• 2005

이러닝의 중요성과문화산업에의 파급효과 및 장래성에 대하여는 이미 많은 문건이나 발표로 알려져 있다. 이렇게 여러 분야에 중요한 효과를 가져가기 위해서는 교육의 양적 성장 뿐 만 아니라 효율적인 교육과 이에 대한 효과에 대해 관심을 기울여야 한다. 이미 미국이나 유럽을 중심으로 각종 이러닝 관련 연구를 통해 ROE(교육투자회임) 연구와 더불어 품질인증(QA : Quality Assurance)에 대한 중요성이 부각되고 있다. 이러한 움직임은 이러닝을 위한 교육자원의 상호운용 또는 활용이라는 측면에서 강조되어 온 이러닝 표준화와 연계되어 그 움직임이 활발히 진행되고 있다. 이러닝 품질표준화의 논의는 단순히 교육자원의 상호운용과 재사용이라는 측면에서 제시되어 온 메타데이터 관리 차원의 SCORM과 같은 기준 외에 교육자원의 생성으로부터 교육시스템 및 교육과정 운영에 이르기까지 그 영역이 광범위한 것에 주목할 필요가 있으며, 국가와 문화적으로도 다양한 환경을 고려해야만 할 것이다. 본고에서는 이러닝 품질보증 표준화의 정의와 범위 그리고 표준안을 만들기 위한 수행절차 및 적용방법 등을 살펴본 후에 외국의 개발 현황과 국내의 개발 현황을 비교함으로써 우리가 가져야 할 미래지향적 표준전략을 제시하고자 한다.

• Korean Journal of Child Studies
• /
• v.12 no.1
• /
• pp.5-20
• /
• 1991

The purpose of this study was to investigate developmental tendencies and age-related differences in the relationship between children's cognitive and emotional perspective-taking ability. The subjects were 4-year-old (N=60), 6-year-old (N=60) and 8-year-old (N=60) children. In each group, there were an equal number of boys and girls. Feshbach & Roe's child perspective-taking ability test was modified for this study. The test included four facial expression cards and six different stories inducing three types of emotion: happy, sad and angry. This experiment consisted of a 3 (age) by 3 (emotional stories: happy, sad and angry) factorial design. The dependent measures were two response types: emotional and cognitive perspective-taking ability. The results showed that both cognitive and emotional perspective-taking ability increased with age. Happy emotional perspective-taking ability developed earlier than sad and angry perspective-taking ability. The correlation between cognitive and emotional perspective-taking ability increased with age.

• Journal of computational fluids engineering
• /
• v.9 no.1
• /
• pp.34-40
• /
• 2004

Recently with growth in the capability of super computers and Parallel computers, shape design optimization is becoming easible for real problems. Also, Computational Fluid Dynamics(CFD) techniques have been improved for higher reliability and higher accuracy. In the shape design optimization, analysis solvers and optimization schemes are essential. In this work, the Roe's 2nd-order Upwind TVD scheme and DADI time march with multigrid were used for the flow solution with the Euler equation and FDM(Finite Differenciation Method), GA(Genetic Algorithm) and Kriging were used for the design optimization. Kriging were applied to 2-D airfoil design optimization and compared with FDM and GA's results. When Kriging is applied to the nonlinear problems, satisfactory results were obtained. From the result design optimization by Kriging method appeared as good as other methods.

• The Korean Journal of Financial Management
• /
• v.14 no.3
• /
• pp.263-287
• /
• 1997

본 연구에서는 국내은행의 위험도가 반영된 보험요율을 Merton에 의해 처음으로 제시된 예금보험요율 결정모형을 이용하여 추정하였다. 실증분석 결과에 의하면 표본은행간의 예금보험요율의 추정치에는 횡단면적 차이가 있는 것으로 나타나 표본기간 중 여러 은행들이 공격적 경영을 취함으로써 은행파산의 위험도를 높이는 도덕적 위해의 문제를 발생시켰음을 보여주고 있다. 본 연구는 상관관계 분석을 통하여 추정된 보험요율이 Moody's사의 국내은행에 대한 장기신용등급과 재무건전도등급, 그리고 은행규모, 수익성, 자본적정성, 자산건전성을 나타내는 지표들과 어떠한 관계에 있는 지를 살펴보았다. 분석결과에 의하면 Moody's사의 국내은행에 대한 장기신용등급, 재무건전도등급과 보험요율 사이에는 통계적으로 유의한 관계가 있는 것으로 나타나 추정된 보험요율이 이들 지표와 마찬가지로 위험도를 적절히 반영하는 것으로 나타났다. 또한 보험요율은 은행규모, ROA, ROE들과는 음의 관계가 있는 것으로 나타났으나, BIS기준 자기자본비율, 부실여신비율과는 양의 관계가 있는 것으로 나타났다. 그러나 자기자본비율이나 부실여신비율이 은행의 신용도나 위험도를 적절하게 반영하지 못하는 것으로 나타남으로써 이들 비율에 대한 회계방식의 개선이 요구됨을 본 연구의 결과는 보여주고 있다.

• Journal of computational fluids engineering
• /
• v.20 no.3
• /
• pp.27-34
• /
• 2015

In this study, preconditioned adjoint equations for the quasi one-dimensional Euler equations are developed, and their computational benefit at all speed is assessed numerically. The preconditioned adjoint equations are derived without any assumptions on the preconditioning matrix. The dissipation for Roe type numerical flux is also suggested to scale the dissipation term properly at low Mach numbers as well as at high Mach numbers. The new preconditioned method is validated against analytical solutions. The convergence characteristics over wide range of Mach numbers is evaluated. Finally, several inverse designs for the nozzle are conducted and the applicability of the method is demonstrated.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.7
• /
• pp.2347-2355
• /
• 1996

Purpose of the present study is to develop a computational design program for shape optimization, combining the numerical optimization technique with the flow analysis code. The present methodology is then validated in three cases of aerodynamic shape optimization. In the numerical optimization, a feasible direction optimization algorithm and shape functions are considered. In the flow analysis, the Navier-Stokes equations are discretized by a cell-centered finite volume method, and Roe's flux difference splitting TVD scheme and ADI method are used. The developed design code is applied to a transonic channel flow over a bump, and an external flow over a NACA0012 airfoil to minimize the wave drag induced by shock waves. Also a separated subsonic flow over a NACA0024 airfoil is considered to determine a maximum allowable thickness of the airfoil without separation.

• Journal of Microbiology
• /
• v.44 no.1
• /
• pp.121-125
• /
• 2006

Mycothiol is a low molecular weight thiol compound produced by a number of actinomycetes, and has been suggested to serve both anti-oxidative and detoxifying roles. To investigate the metabolism and the role of mycothiol in Streptomyces coelicolor, the biosynthetic genes (mshA, B, C, and D) were predicted based on sequence homology with the mycobacterial genes and confirmed experimentally. Disruption of the mshA, C, and D genes by PCR targeting mutagenesis resulted in no synthesis of mycothiol, whereas the mshB mutation reduced its level to about $10\%$ of the wild type. The results indicate that the mshA, C, and D genes encode non-redundant biosynthetic enzymes, whereas the enzymatic activity of MshB (acetylase) is shared by at least one other gene product, most likely the mca gene product (amidase).

• Journal of Microbiology
• /
• v.38 no.3
• /
• pp.156-159
• /
• 2000

The cttl+ gene in Schizosaccharomyces pombe encoeds a catalse responsible for H2O2-resistance of this organism as judged by the H2O2-sensitive phenotype of the ctt1Δ mutant. In this study, we investigated the subcellular localization of the Ctt1 gene product. In wild type cells catalase activity was detected in the organelle fraction as well as in the cytosol. The ctt1Δ mutant contained no catalase activity, indicating that both cytosolic and organellar catalases are the products of a single ctt1+ gene. Western bolt analysis revealed two catalase bands, both of which disappeared in the ctt1Δ mutant. The major, fastermigrating band existed in the cytosol whereas the monor, slower-migrating band appeared to be located in organelles, most likely in peroxisomes. These results suggest that the ctt1+ gene product targeted to the peroxisome is a modified form of the one in the cytosol.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.514-519
• /
• 1997

The MRX is an integral type ship reactor with 100 MWt power, which is designed by Japan Atomic Energy Research Institute. It is characterized by integral type PWR, in-vessel type control roe drive mechanism, water-filled containment vessel and passive decay heat removal system. Marine reactor should have high passive safety. Therefore, in this study, we simulated the loss of flow accident to verify the passive decay heat removal by natural circulation using RETRAN-03 code. auxiliary feed water systems are used for decay heat removal mechanism and results are compared with the loss of flow accident analysis using emergency decay heat removal system by JAERI. Results are very similar to case of EDRS 1 loop operation in JAERI analysis and decay heat is successfully removed by natural circulation.