• Journal of the Korean Statistical Society
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• v.29 no.3
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• pp.361-373
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• 2000

A simple and efficient algorithm is introduced for generalized least squares estimation under nonnegativity constraints in the components of the parameter vector. This algorithm gives the exact solution to the estimation problem within a finite number of pivot operations. Besides an illustrative example, an empirical study is conducted for investigating the performance of the proposed algorithm. This study indicates that most of problems are solved in a few iterations, and the number of iterations required for optimal solution increases linearly to the size of the problem. Finally, we will discuss the applicability of the proposed algorithm extensively to the estimation problem having a more general set of linear inequality constraints.

• Proceedings of the Acoustical Society of Korea Conference
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• 1992.06a
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• pp.71-75
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• 1992

This paper proposes algorithm in order to classify Korean consonant phonemes same as polosives, fricatives affricates into la sounds, glottalized sounds, aspirated sounds. This three kinds of sounds are one of distinctive characters of the Korean language which don't eist in language same as English. This is thesis on classfication of 14 Korean consonants(k, t, p, s, c, k', t', p', s', c', kh, ph, ch) as a previous stage for Korean phone recognition. As feature sets for classification, LPC cepstral analysis. The eperiments are two stages. First, using short-time speech signal analysis and Mahalanobis distance, consonant segments are detected from original speech signal, then the consonants are classified by fuzzy inference. As the results of computer simulations, the classification rate of the speech data was come to 93.75%.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.113-123
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• 2014

Electrophysiological recordings are considered a reliable method of assessing a person's alertness. Sleep medicine is asked to offer objective methods to measure daytime alertness, tiredness and sleepiness. As EEG signals are non-stationary, the conventional method of frequency analysis is not highly successful in recognition of alertness level. In this paper, EEG signals have been analyzed using wavelet transform as well as discrete wavelet transform and classification using statistical classifiers such as euclidean and mahalanobis distance classifiers and a promising method SVM (Support Vector Machine). As a result of simulation, the average values of accuracies for the Linear Discriminant Analysis (LDA)-Quadratic, k-Nearest Neighbors (k-NN)-Euclidean, and Linear SVM were 48%, 34.2%, and 86%, respectively. The experimental results show that SVM classification method offer the better performance for reliable classification of the EEG signal in comparison with the other classification methods.

• Proceedings of the KSRS Conference
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• 2001.03a
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• pp.62-69
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• 2001

본 연구에서는 해상도가 상이한 시기별 위성영상과 GIS를 이용하여 경남 통영시 한산면 추봉도 지역의 소나무재선충(Bursaphelenchus Xylophilus) 피해지역을 탐지하고 다양한 영상처리를 통하여 이를 효율적으로 추출 할 수 있는 기법을 선정하였다. 연구결과 피해지역의 공간적 범위를 추출하기 위해서는 감독분류의 MHC(Mahalanobis Distance Classification)가 유용하였고 벌채 후의 토지피복 분류로 인한 피해지역 추출을 위해서는 MLC(Maximum Likelihood Classification)가 최적한 기법으로 나타났다. 아울러 이에 관련된 GIS를 구축하여 공간정보를 추출함으로써 피해지역의 공간적 분포특성을 규명하였는데 고도 약 120-160m, 경사 21$^{\circ}$-40$^{\circ}$ 그리고 서쪽 방향 사면에서 소나무재선충이 가장 활발하게 활동하였음이 밝혀졌다.

• Communications for Statistical Applications and Methods
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• v.22 no.1
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• pp.55-67
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• 2015

An important problem in cluster analysis is the selection of variables that define cluster structure that also eliminate noisy variables that mask cluster structure; in addition, outlier detection is a fundamental task for cluster analysis. Here we provide an automated K-means clustering process combined with variable selection and outlier identification. The Automated K-means clustering procedure consists of three processes: (i) automatically calculating the cluster number and initial cluster center whenever a new variable is added, (ii) identifying outliers for each cluster depending on used variables, (iii) selecting variables defining cluster structure in a forward manner. To select variables, we applied VS-KM (variable-selection heuristic for K-means clustering) procedure (Brusco and Cradit, 2001). To identify outliers, we used a hybrid approach combining a clustering based approach and distance based approach. Simulation results indicate that the proposed automated K-means clustering procedure is effective to select variables and identify outliers. The implemented R program can be obtained at http://www.knou.ac.kr/~sskim/SVOKmeans.r.

• Agricultural and Biosystems Engineering
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• v.5 no.1
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• pp.25-29
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• 2004

Fluorescence spectroscopy was used to characterize chicken carcass diseases. Spectral signatures of three different disease categories of poultry carcasses (airsacculitis, cadaver and septicemia) were obtained from fluorescence emission measurements in the wavelength range of 360 to 600 nm with 330 nm excitation. Principal Component Analysis (PCA) was used to select the most significant wavelengths for the classification of poultry carcasses. These wavelengths were analyzed for pathologic correlation of poultry diseases. Using a Soft Independent Modeling of Class Analogy (SIMCA) of principal components with a Mahalanobis distance metric, poultry carcasses were individually classified into different classes with $97.9\%$ accuracy.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.82-89
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• 2013

Novelty detection (ND) is an effective technique that can be used to determine whether a future observation is normal or not. In the present study we propose a novelty detection algorithm that can handle a situation where the distributions of target (normal) observations are inhomogeneous. A simulation study and a real case with the TFT-LCD process demonstrated the effectiveness and usefulness of the proposed algorithm.

• Journal of Biosystems Engineering
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• v.23 no.4
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• pp.343-350
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• 1998

Spectroscopic analysis of soybean kernels were made in the wavelength range of 400 to 1100 nm to find effective discrimination factors which are required for developing an opitical soybean sorter. Soybean samples used for the test were the sound and five classes of the defective kernels such as the immature, discolored(brown and violet), damaged by insect and diseased. Effective discrimination factors to classify the soybean kernels into the sound and the defective were found to be $R_{640}$, $R_{580}$/ $R_{990}$, $R_{600}$- $R_{820}$ and ( $R_{590}$- $R_{820}$)/ $R_{990}$. with classification error of less than 4%. Mahalanobis distance was used as a criterion to select significant wavelengths involved in the discrimination factors.s.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.266-271
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• 1998

본 논문에서는 칼라지도영상으로부터 GIS의 벡터링 과정에 사용할 벡터링 영역(도로, 해안선, 등고선 등)을 추출하는 방법에 대해 연구하였다. 입력영상으로는 트루칼라영상을 사용할 경우 추출 영역의 칼라가 비교적 균일하게 분포되지만 데이터량이 방대하여 처리에 어려움이 있어 현실적이지 못하므로 이를 양자화하여 256칼라 영상으로 변환한 후 사용할 수 있도록 하였다. 추출 단계에서는 Lab칼라공간에서 mahalanobis 거리 및 방향성 마스크를 사용하여 다양한 칼라 분포를 흡수할 수 있도록 하여 배경 영역을 배제하면서 연결성이 있는 추출결과를 얻을수 있도록 하였다. 그리고 추출된 결과를 원영상과 중첩해 보면서 기호, 문자 등의 요소로 인해 끊어진 영역이나 추출시 발생되는 피할 수 없는 잡영을 편집하여 제거할 수 있는 기능을 제공하였다. 추출된 결과는 벡터링 작업에 직접 사용 가능한 형태로 추출되도록 하였는데 실제 벡터링 작업에 다양한 추출영역을 사용해 봄으로써 이를 검증하였다.

• Communications for Statistical Applications and Methods
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• v.10 no.3
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• pp.971-980
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• 2003

The tree method can be extended to multivariate responses, such as repeated measure and longitudinal data, by modifying the split function so as to accommodate multiple responses. Recently, some decision trees for multiple responses have been constructed by Segal (1992) and Zhang (1998). Segal suggested a tree can analyze continuous longitudinal response using Mahalanobis distance for within node homogeneity measures and Zhang suggested a tree can analyze multiple binary responses using generalized entropy criterion which is proportional to maximum likelihood of joint distribution of multiple binary responses. In this paper, we will modify CART procedure and suggest a new tree-based method that can analyze multiple binary responses using similarity measures.