• Communications for Statistical Applications and Methods
• /
• v.18 no.6
• /
• pp.761-770
• /
• 2011

Robust principal components regression is suggested to deal with both the multicollinearity and outlier problem. A main aspect of the robust principal components regression is the selection of an optimal set of principal components. Instead of the eigenvalue of the sample covariance matrix, a selection criterion is developed based on the condition index of the minimum volume ellipsoid estimator which is highly robust against leverage points. In addition, the least trimmed squares estimation is employed to cope with regression outliers. Monte Carlo simulation results indicate that the proposed criterion is superior to existing ones.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04a
• /
• pp.595-597
• /
• 2002

본 연구는 주어진 병렬 프로그램에 대해서 병릴 시스템의 성능을 효과적으로 이끌어낼 수 있는 최적 프로세서 수를 결정하는 방법에 관한 것이다. 최적 프로세서 수는 병렬 시스템의 성능 뿐만 아니라 비용도 같이 고려하여 이들 조건이 균형을 이루어 가상 효율적인 성능을 이끌어낼 수 있는 병렬 시스템의 프로세서 수로 정의된다. 최적 프로세서 수는 주어진 병렬 프로그램에 대해서 얼마나 많은 프로세서를 사용할 수 있는지 알려줄 수 있으므로, 보다 객관적이고 구체적인 병렬 시스템의 확장성 기준으로도 사용될 수 있다.

• The Korean Journal of Applied Statistics
• /
• v.28 no.3
• /
• pp.561-571
• /
• 2015

When we consider an optimal design to predict the response corresponding to the point outside the design region, we are extremely careful about choosing the design criteria for selecting the support points. The assumed model and its accompanying error structure should be assumed to extend beyond the design region for the selected design criteria to be valid. Thus, we modify the existing design criteria such as extrapolation-optimality to be suited to those situations. We propose some maximin approaches in this paper. Simple and quadratic regression models are tested to find the basic characteristics of such maximin approaches. Some main findings are discussed in the conclusion.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.49 no.4
• /
• pp.54-61
• /
• 2012

This paper proposes a fusion method of the queen-bee evolution into the rank-based control of mutation probability for improving the performances of genetic algorithms. The rank-based control of mutation probability which showed some performance improvements than the original method was a method that prevented individuals of genetic algorithms from falling into local optimum areas and also made it possible for the individuals to get out of the local optimum areas if they fell into there. This method, however, showed not good performances at the optimization problems that had a global optimum located in a small area regardless of the number of local optimum areas. We think that this is because the method is insufficient in the convergence into the global optimum, so propose a fusion method of the queen-bee evolution into this method in this paper. The queen-bee evolution inspired by reproduction process of queen-bee is a method that can strengthen the convergency of genetic algorithms. From the extensive experiments with four function optimization problems in order to measure the performances of proposed method we could find that the performances of proposed method was considerably good at the optimization problems whose global optimum is located in a small area as we expected. Our method, however, showed not good performances at the problems whose global optima were distributed in broad ranges and even showed bad performances at the problems whose global optima were located far away. These results indicate that our method can be effectively used at the problems whose global optimum is located in a small area.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.40 no.2
• /
• pp.26-37
• /
• 2003

An optimal software release, which is related to the development cost, error detection and correction under the various operation systems, is a critical factor for managing project. This paper described optimal software release issues to predict the release time of large switching system with the system stability point of view and evaluated a timely supply of target system, proper utilization of resources under the software reliability valuation basis. Finally, Using initial failure data, based on the exponential reliability growth model methodology, optimal release time, and analysis of failure data during the system testing and managing methodologies were presented.

• Proceedings of the KAIS Fall Conference
• /
• 2010.11b
• /
• pp.850-854
• /
• 2010

본 연구는 ANP법을 활용하여 전평시 군수지원 시스템에 대한 운용평가 방안을 제시하였다. 이러한 평가를 위하여 본 연구에서는 군 실정에 부합한 평가기준 재정립하여 기준별 구체적인 평가방법을 제시하였다. 그에따라 연구에서는 시뮬레이션을 이용하여 시스템 운용의 최적조합을 판단하는 과정과 정수계획법을 통한 수리적 모델링으로 군수품의 배송비용에 대한 경제성 평가를 제시하였고 회귀분석을 통한 효용성 평가와 IPB에 의한 군수품 수송의 안정성 평가를 실시하였다. 마지막으로 이러한 각 평가 결과를 ANP법을 이용한 종합 평가치를 산출하여 전평시 지휘관 및 참모의 부대지휘절차간에 구체적인 방책구상 및 선정시 지휘관이 최적의 의사결정할 수 있도록 하였다.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.463-464
• /
• 2007

본 논문은 경제성 및 안정성을 유지하는 최적의 전압유지범위 설정을 위해 다양한 목적함수를 최적조류계산에 이용하였다. 경제성을 위해 융통전력 최대화와 유효전력 손실최소화를 목적함수로 하였고 안정성을 위해 무효전력예비력 최대화를 목적함수로 하였다. 또한 경제성과 안정성을 모두 반영하기 위해 다목적 함수를 구성하였다. 최적화기법을 실계통에 적용하였을 때 목적함수를 얼마나 잘 만족시킬 수 있는지 각종 지표를 통해 살펴보았다. 그리고 모니터링 모선의 전압 변동 추이를 살펴보고 이를 통해 경제성 및 안정성을 유지하는 최적의 전압유지 범위설정을 하는데 활용할 수 있도록 하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.4
• /
• pp.309-317
• /
• 2007

Cadastral control points in Korea are refered to various origins, for example an early separated small triangulation, a separated small triangulation, a separated control surveying origin and an unified origin. Cadastral map with early separated small triangulation origin have difficulties to connect with national GIS data by refered an unified origin. We determined transformation parameters from old origin to unified origin using 2D conformal transformation method. To evaluate of transformation accuracy, we compared with GPS field surveying results. And we experiment on coordinate transformations with unified results between the local geodetic datum and the new Korea geodetic datum.

• The Korean Journal of Applied Statistics
• /
• v.11 no.2
• /
• pp.435-449
• /
• 1998

In this article we have introduced a Bayes criterion for the variable selection in multiple discriminant analysis (MDA). The criterion is a default Bayes factor for the comparision of homo/heteroscadasticity of the multivariate normal means. The default Bayes factor is obtained from a development of the imaginary training sample method introduced by Spiegelhalter and Smith (1982). Based an the criterion, we also provided a test for additional discrimination in MDA. The advantage of the criterion is that it is not only applicable for the optimal subset selection method but for the stepwise method. More over, the criterion can be reduced to that for two-group discriminant analysis. Thus the criterion can be regarded as an unified alternative to variable selection criteria suggested by various sampling theory approaches. To illustrate the performance of the criterion, a numerical study has bean done via Monte Carlo experiment.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.287-291
• /
• 2009

지구 온난화의 영향으로 최근 이상홍수에 의한 피해가 증가하고 있다. 국내 다목적댐의 경우 월별 목표수위를 기준으로 하는 저수지 운영률이 존재하지만 이것은 실제 이상홍수가 발생할 경우 저수지 운영에 도움을 주지 못하는 것이 현실이다. 본 연구에서는 자원배분문제의 최적해를 찾는데 사용되는 최적화기법의 하나인 선형계획법과 수자원 문제와 같이 불확실성이 산재해있고, 애매모호한 문제를 다루기에 적합한 퍼지제어 기법을 적용하여 이상홍수 발생 시 두 개 이상의 다목적댐 군을 연계운영하기 위한 퍼지 최적 운영 기법을 개발하는 것을 목표로 하였다. 시험유역으로는 낙동강 상류에 위치한 안동댐과 임하댐 유역을 대상으로 PMF 발생 시 댐의 안전성을 높이고 안동시 지점에서의 최대홍수량을 최소화하기 위한 퍼지최적운영기법을 개발하였다.