• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.16-19
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• 2001

This paper presents a type-2 fuzzy C-means (FCM) algorithm that is an extension of the conventional fuzzy C-means algorithm. In our proposed method, the membership values for each pattern are extended as type-2 fuzzy memberships by assigning membership grades to the type-1 memberships. In doing so, cluster centers that are estimated by type-2 memberships may converge to a more desirable location than cluster centers obtained by a type-1 FCM method in the presence of noise.

• The KSFM Journal of Fluid Machinery
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• v.9 no.4 s.37
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• pp.43-48
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• 2006

In this study, the effect of flow settling means on the performance of fan tester were numerically investigated by using a computational fluid dynamics(CFD). The airflow rate was calculated from the pressure differential across a flow nozzle in the measuring plane and the flow settling means were generally installed in the chamber of the fan tester to provide proper airflow patterns ahead of the measuring plane. The predicted nozzle differential pressures with uniform inlet velocities were compared with the values of the ANSI/AMCA 210-99 to verify the performance of the commercial CFD code CFX 5.6. The influence of flow settling means on the measurement of airflow rate in a fan tester were discussed with various porosities and inlet jet velocities. The results obtained show that the proper band of porosities exist to meet the AMCA standard in a specified inlet jet velocity.

• IE interfaces
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• v.16 no.spc
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• pp.123-126
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• 2003

In this paper, we use three cluster algorithms (K-means, Self-Organizing Map, and Fuzzy K-means) to find proper graded stock market brokerage commission rates based on the cumulative transactions on both stock exchange market and HTS (Home Trading System). Stock trading investors for both modes are classified in terms of the total transaction as well as the corresponding mode of investment, respectively. Empirical analysis results indicated that fuzzy K-means cluster analysis is the best fit for the segmentation of customers of both transaction modes in terms of robustness. We then propose the rules for three grouping of customers based on decision tree and apply different brokerage commission to be 0.4%, 0.45%, and 0.5% for exchange market while 0.06%, 0.1%, 0.18% for HTS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.386-388
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• 2018

본 논문은 사회적 상호작용 결여로 감정 기복이 심하고 스트레스로 인해 정서불안 증세를 보이는 자폐 범주성 장애아동의 감정 상태를 인식하기 위한 목적으로 4가지 감정 자극에 대하여 생체신호를 분석하고 K-Means 알고리즘을 적용하여 획득한 정보로부터 감정 상태를 인식하는 방법을 제안한다. 실험구성은 참가자가 주어지는 감정자극 영상을 시청하는 동안 맥파 및 피부전도 센서를 이용하여 생체신호를 측정한 후 자율신경 비율을 나타내는 LF/HF의 심박 정보와 피부 반응 정보를 정량적으로 분석하였고, 추출된 정보로부터 K-Means 알고리즘을 적용하여 감정 상태를 분류하는 과정으로 진행된다. 총 3명의 일반인을 대상으로 실험을 진행하였으며, 4가지 감정 자극에 대한 실험을 수행한 결과, 생체신호 측정을 이용한 감정인식 방법이 제시되는 감정 자극을 충분히 분류할 수 있음을 확인할 수 있었다.

• Communications for Statistical Applications and Methods
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• v.22 no.4
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• pp.321-331
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• 2015

The K-means clustering algorithm is a popular and widely used method for clustering. For covariance matrices, we consider a geodesic clustering algorithm based on the K-means clustering framework in consideration of symmetric positive definite matrices as a Riemannian (non-Euclidean) manifold. This paper considers a geodesic clustering algorithm for data consisting of symmetric positive definite (SPD) matrices, utilizing the Riemannian geometric structure for SPD matrices and the idea of a K-means clustering algorithm. A K-means clustering algorithm is divided into two main steps for which we need a dissimilarity measure between two matrix data points and a way of computing centroids for observations in clusters. In order to use the Riemannian structure, we adopt the geodesic distance and the intrinsic mean for symmetric positive definite matrices. We demonstrate our proposed method through simulations as well as application to real financial data.

• Communications for Statistical Applications and Methods
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• v.27 no.4
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• pp.431-443
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• 2020

The K-means clustering algorithm has had successful application in sufficient dimension reduction. Unfortunately, the algorithm does have reproducibility and nestness, which will be discussed in this paper. These are clear deficits for the K-means clustering algorithm; however, the hierarchical clustering algorithm has both reproducibility and nestness, but intensive comparison between K-means and hierarchical clustering algorithm has not yet been done in a sufficient dimension reduction context. In this paper, we rigorously study the two clustering algorithms for two popular sufficient dimension reduction methodology of inverse mean and clustering mean methods throughout intensive numerical studies. Simulation studies and two real data examples confirm that the use of hierarchical clustering algorithm has a potential advantage over the K-means algorithm.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.83-86
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• 2006

많은 유전자 정보와 그 부산물은 많은 방법을 통해 연구되어 왔다. DNA 마이크로어레이 기술의 사용은 많은 데이터를 가져왔으며, 이렇게 얻은 데이터는 기존의 연구 방법으로는 분석하기 힘들다. 본 눈문에서는 많은 양의 데이터를 처리할 수 있게 하기 위하여 K-means 클러스터링 알고리즘을 이용한 분할 클러스터링을 제안하였다. 제안한 방법을 쌀 유전자로부터 나온 마이크로어레이 데이터에 적용함으로써 제안된 클러스터링 방법의 유용성을 검증하였으며, 기존의 K-means 클러스터링 알고리즘을 적용한 결과와 비교함으로써 제안된 알고리즘의 우수성을 확인 할 수 있었다.

• Journal of information and communication convergence engineering
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• v.16 no.4
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• pp.258-263
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• 2018

Color Doppler sonography is a useful tool for examining blood flow and related indices. However, it should be done by well-trained operator, that is, operator subjectivity exists. In this paper, we propose an automatic blood flow area extraction method from brachial artery that would be an essential building block of computer aided color Doppler analyzer. Specifically, our concern is to examine hypertension suspicious (prehypertension) patients who might develop their symptoms to established hypertension in the future. The proposed method uses fuzzy C-means clustering as quantization engine with careful seeding of the number of clusters from histogram analysis. The experiment verifies that the proposed method is feasible in that the successful extraction rates are 96% (successful in 48 out of 50 test cases) and demonstrated better performance than K-means based method in specificity and sensitivity analysis but the proposed method should be further refined as the retrospective analysis pointed out.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1132-1134
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• 2013

K-Means 클러스터링 기법은 데이터마이닝 분야 중 클러스터링 분야에서 가장 널리 쓰이는 방법 중 하나로 주어진 데이터 셋에서 k개의 클러스터를 중심으로 데이터를 분할하는 기법이다. 최근의 데이터는 여러개의 속성을 고려해야 한다. 따라서 본 논문에서는 K-Means 클러스터링 기법을 소개하고, 또 K-Means 클러스터링 기법을 여러 개의 속성을 고려하기 위하여 다차원 데이터에 적용한 실험을 소개한다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.4
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• pp.1-11
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• 2023

Clustering analysis is used in various fields including customer segmentation and clustering methods such as k-means are actively applied in the credit card customer segmentation. In this paper, we summarized the input features selection method of k-means clustering for the case of the credit card customer segmentation problem, and evaluated its feasibility through the analysis results. By using the label values of k-means clustering results as target features of a decision tree classification, we composed a method for prioritizing input features using the information gain of the branch. It is not easy to determine effectiveness with the clustering effectiveness index, but in the case of the CH index, cluster effectiveness is improved evidently in the method presented in this paper compared to the case of randomly determining priorities. The suggested method can be used for effectiveness of actively used clustering analysis including k-means method.