• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.432-436
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• 2009

We have developed a new optimization algorithm termed simple bacteria cooperative optimization (sBCO) based on bacteria behavior patterns [1]. In [1], we have introduced the algorithm with basic operations and showed its feasibility with some function optimization problems. Since the sBCO was the first version with only basic operations, its performance was not so good. In this paper, we adopt a new operation, rank replacement, to the sBCO for improving its performance and compare its results to those of the simple genetic algorithm (sGA) which has been well known and widely used as an optimization algorithm. It was found from the experiments with four function optimization problems that the sBCO with rank replacement was superior to the sGA. This shows that our algorithm can be a good optimization algorithm.

• Communications for Statistical Applications and Methods
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• v.9 no.1
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• pp.75-86
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• 2002

We consider the problem of estimating the change-point in mean change model with one change-point. Gombay and Huskova(1998) derived a class of change-point estimators with the score function of rank. A change-point estimator with the log score function of rank is suggested and is shown to be involved in the class of Gombay and Huskova(1988). The simulation results show that the proposed estimator has smaller rose, larger proportion of matching the true change-point than the other estimators considered in the experiment when the change-point occurs in the middle of the sample.

• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.159-171
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• 1994

Some rank score tests are proposed for testing the equality of all sampling distribution functions against umbrella location-scale alternatives in k-sample problem. Only the case of known peak $\ell$ is considered. Under the null hypothesis and a contiguous sequence of unbrella location-scale alternatives, the asymptotic properties of the proposed test statistics are investigated. Also, the asymptotic local powers are compared with each others. The results show that the tests based on the Chen-Wolfe rank analogue statistic are more powerful than others for unequally spaced umbrella location-scale alternatives and robust.

• Annual Conference of KIPS
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• 2019.10a
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• pp.653-656
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• 2019

소프트웨어의 유지보수 단계에서 소프트웨어의 버그 리포트는 개발자에게 유용한 정보를 제공한다. 개발자들은 버그 수정이나 변경 내역 열람 등 다양한 작업을 위해 버그 리포트를 열람한다. 하지만, 대화 형식으로 작성되는 버그 리포트의 특징 때문에 버그 리포트는 종종 매우 길거나 장황하여 이를 읽고 이해하기 어려운 경우가 많다. 이러한 문제점을 해결하기 위한 방법으로 버그 리포트의 요약문을 자동으로 생성하는 기법을 제안하였고, 다양한 관련 연구가 진행되었다. 그러나, 기존에 제안된 버그 리포트 요약 기법들은 버그 리포트만의 고유한 특성들을 활용하지 않는 경우가 많다. 본 연구에서는 버그 리포트들 사이의 중복(duplicates), 의존(depends-on), 역의존(blocks) 관계들을 이용한 PageRank 알고리즘 기반 버그 리포트 요약 기법을 제안한다. 실험 결과 제안 기법이 기존 버그 리포트 요약 기법보다 요약 품질과 적용 범위 측면에서 뛰어남을 확인하였다.

• ETRI Journal
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• v.41 no.5
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• pp.619-625
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• 2019

In this paper, we propose an array pattern synthesis scheme using semidefinite programming (SDP) under array excitation power constraints. When an array pattern synthesis problem is formulated as an SDP problem, it is known that an additional rank-one constraint is generated inevitably and relaxed via semidefinite relaxation. If the solution to the relaxed SDP problem is not of rank one, then conventional SDP-based array pattern synthesis approaches fail to obtain optimal solutions because the additional rank-one constraint is not handled appropriately. To overcome this drawback, we adopted a bisection technique combined with a penalty function method. Numerical applications are presented to demonstrate the validity of the proposed scheme.

• Journal of the Korean Mathematical Society
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• v.61 no.2
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• pp.279-291
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• 2024

In this paper, we investigate a few strategies to construct Ulrich bundles of small ranks over smooth fourfolds in ℙ⁵, with a focus on the case of special quartic fourfolds. First, we give a necessary condition for Ulrich bundles over a very general quartic fourfold in terms of the rank and the Chern classes. Second, we give an equivalent condition for Pfaffian fourfolds in every degree in terms of arithmetically Gorenstein surfaces therein. Finally, we design a computer-based experiment to look for Ulrich bundles of small rank over special quartic fourfolds via deformation theory. This experiment gives a construction of numerically Ulrich sheaf of rank 4 over a random quartic fourfold containing a del Pezzo surface of degree 5.

• Communications for Statistical Applications and Methods
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• v.14 no.1
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• pp.169-182
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• 2007

Receive operating characteristic (ROC) approach can be employed to rank candidate genes from a microarray experiment, in particular, for the biomarker development with the purpose of population screening of a cancer. In the cancer microarray experiment based on n patients the researcher often wants to compare the tumor tissue with the normal tissue within the same individual using a common reference RNA. Ideally, this experiment produces n pairs of microarray data. However, it is often the case that there are missing values either in the normal or tumor tissue data. Practically, we have $n_1$ pairs of complete observations, $n_2$ "normal only" and $n_3$ "tumor only" data for the microarray. We refer to this data set as a mixed data set. We develop a ROC approach on the mixed data set to rank candidate genes for the biomarker development for the colorectal cancer screening. It turns out that the correlation between two ranks in terms of ROC and t statistics based on the top 50 genes of ROC rank is less than 0.6. This result indicates that employing a right approach of ranking candidate genes for the biomarker development is important for the allocation of resources.

• Journal of KIISE:Software and Applications
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• v.27 no.7
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• pp.723-730
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• 2000

Fuzzy numbers represent fuzzy numeric values. However, it is difficult to clearly determine whether one fuzzy number is larger or smaller than other fuzzy numbers. Thus it is also difficult to determine the rank which a fuzzy number takes, or to select the k-th largest fuzzy number in a given set of fuzzy numbers. In this paper, we propose a fuzzy set based method to determine the rank of a fuzzy number and the k-th largest fuzzy number. The proposed method uses a given fuzzy greater-than relation which is defined on a set of fuzzy numbers. Our method describes the rank of a fuzzy number with a fuzzy set of ranks that the fuzzy number can take, and the k-th largest fuzzy number with a fuzzy set of fuzzy numbers which can be k-th ranked.

• Journal of Korean Society of Rural Planning
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• v.13 no.4
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• pp.9-22
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• 2007

With the establishment of municipalities, public interest in small towns in Korea has been on the rise. To initiate an effective study and suggest subsequent policies for small towns, it is necessary to analyze and discuss substantive issues based on specific conditions of these small towns. The primary objective of this paper is to categorize small towns into types and to analyze the peculiarities and differences of their internal factors. The focus of this research is to determine the general characteristics of the classified towns and to suggest specific revitalization and specialized studies about them. In the main analysis of this paper, 39 small towns are divided into sets according to urban rank, conditions of location, and size of the population in the central site. Furthermore, distinctions of the divided towns are analyzed using three constituents for urban organization, including populations, activities, and facilities/land. From the research results, it was determined that there is a difference between small town types, according to population, land cost, and urban activities, based upon the urban rank and size of the population in the central site. Therefore, this paper concludes it is necessary to conduct further studies on time series analysis regarding the peculiarity changes of the types, and to complement the variables for future related studies.

• Journal of Information Management
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• v.37 no.2
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• pp.33-50
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• 2006

In this paper, after reviewing hyperlink based ranking methods, we saw various other parameters that effect ranking. Then, We analyzed the PageRank and HITS(Hypertext Induced Topic Search) algorithm, which are two popular methods that use eigenvector computations to rank results in terms of their characteristics. Finally, google and Ask.com search engines were examined as examples for applying those methods. The results showed that use of Hyperlink structure can be useful for efficiency of web site search.