• The Korean Journal of Applied Statistics
• /
• v.30 no.6
• /
• pp.867-876
• /
• 2017

Datasets with small n and large p are often found in various fields and the analysis of the datasets is still a challenge in statistics. Discriminant analysis models for such datasets were recently developed in classification problems. One approach of those models tries to detect dimensions that distinguish between groups well and the number of the detected dimensions is typically smaller than p. In such models, the number of dimensions is important because the prediction and visualization of data and can be usually determined by the K-fold cross-validation (CV). However, in sparse data scenarios, the CV is not reliable for determining the optimal number of dimensions since there can be only a few observations for each fold. Thus, we propose a method to determine the number of dimensions using a measure based on the standardized distance between the mean values of each group in the reduced dimensions. The proposed method is verified through simulations.

• Journal of Korea Technology Innovation Society
• /
• v.10 no.2
• /
• pp.183-205
• /
• 2007

An investigation was undertaken of the optimal discriminant model for predicting the likelihood of insolvency in advance for medium-sized firms based on the technology evaluation. The explanatory variables included in the discriminant model were selected by both factor analysis and discriminant analysis using stepwise selection method. Five explanatory variables were selected in factor analysis in terms of explanatory ratio and communality. Six explanatory variables were selected in stepwise discriminant analysis. The effectiveness of linear discriminant model and logistic discriminant model were assessed by the criteria of the critical probability and correct classification rate. Result showed that both model had similar correct classification rate and the linear discriminant model was preferred to the logistic discriminant model in terms of criteria of the critical probability In case of the linear discriminant model with critical probability of 0.5, the total-group correct classification rate was 70.4% and correct classification rates of insolvent and solvent groups were 73.4% and 69.5% respectively. Correct classification rate is an estimate of the probability that the estimated discriminant function will correctly classify the present sample. However, the actual correct classification rate is an estimate of the probability that the estimated discriminant function will correctly classify a future observation. Unfortunately, the correct classification rate underestimates the actual correct classification rate because the data set used to estimate the discriminant function is also used to evaluate them. The cross-validation method were used to estimate the bias of the correct classification rate. According to the results the estimated bias were 2.9% and the predicted actual correct classification rate was 67.5%. And a threshold value is set to establish an in-doubt category. Results of linear discriminant model can be applied for the technology financing banks to evaluate the possibility of insolvency and give the ranking of the firms applied.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2007.04a
• /
• pp.295-298
• /
• 2007

본 논문에서는 사람의 얼굴표정을 통해 4개의 기본감정(기쁨, 슬픔, 화남, 놀람)에 대한 특징을 추출하고 인식하여 그 결과를 이용하여 감정표현 시스템을 구현한다. 먼저 주성분 분석(Principal Component Analysis)법을 이용하여 고차원의 영상 특징 데이터를 저차원 특징 데이터로 변환한 후 이를 선형 판별 분석(Linear Discriminant Analysis)법에 적용시켜 좀 더 효율적인 특징벡터를 추출한 다음 감정을 인식하고, 인식된 결과를 얼굴 표현 시스템에 적용시켜 감정을 표현한다.

• Communications for Statistical Applications and Methods
• /
• v.17 no.4
• /
• pp.561-574
• /
• 2010

We studied the performance of 8 data mining algorithms including decision trees, logistic regression, LDA, QDA, Neral network, and SVM and their combinations of 2 ensemble techniques, bagging and boosting. In this study, we utilized 13 data sets with binary responses. Sensitivity, Specificity and missclassificate error were used as criteria for comparison.

• Food Science of Animal Resources
• /
• v.30 no.2
• /
• pp.313-320
• /
• 2010

The purpose of this study was to evaluate the freshness of chicken meat during 19 d of storage at $4^{\circ}C$ using a portable electronic nose. The portable system consisted of six different metal oxide sensors and a moisture sensor. Determination of volatile compounds with gas chromatography-mass spectrometry, total bacterial count (TBC), and 2-thiobarbituric acid reactive substances (TBARS) monitored the quality change of the samples. These results were compared with the results measured by the electronic nose system. TBC and TBARS measurements could be separated into five groups and seven groups, respectively, among ten groups. According to principal component analysis and linear discriminant analysis with the signals of the portable electronic nose, the sample groups could be clearly separated into eight groups and nine groups, respectively, among ten groups. The portable electronic nose demonstrated potential for evaluating freshness of stored chicken.

• Proceedings of the KIPE Conference
• /
• 2020.08a
• /
• pp.172-174
• /
• 2020

기존의 절대위치 감지 방식은 초기위치를 알기 위하여 이동자의 위치를 초기화해야 하고 생산 단가가 높다는 단점을 보완하기 위해 MR 센서를 이용하여 비접촉 방식으로 선형모터 이동자 절대위치를 판별하는 시스템을 제안하였다. 센서값을 이용하여 절대위치를 판별해야 하기 때문에 ADC 기능과 실시간 연산 기능이 필요하다. 때문에 8bit MCU(Atmega324PA)를 이용했다. 본 논문에서 이용한 MR 센서의 출력 변동폭이 작기 때문에 Instrumentation Amplifier를 이용하여 증폭된 출력을 MCU로 읽어 사용했다. 제안 시스템의 회로 및 알고리즘을 구현하였고 이를 이론적, 실험적 분석을 통해 동작 및 타당성을 검증하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2010.11a
• /
• pp.129-130
• /
• 2010

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.1
• /
• pp.196-204
• /
• 2008

In this paper, we propose an efficient method to classify human facial impression using frontal face image. The features that represent the shape of eye, jaw and face are used. The proposed method employs PCA, LDA and SVM in series. PCA is used to project the feature space to a low dimensional subspace. LDA produces well separated classes in a low dimensional subspace even under severe variation. This results in good discriminating power for classification. SVM is used to classify the data. Human face has been classified for 8 facial impressions. The experiments have been performed for many face images, and show encouraging result.

• Journal of Korea Society of Industrial Information Systems
• /
• v.14 no.3
• /
• pp.106-113
• /
• 2009

Various statistical classification methods have been used to establish prediction model of underground cultural assets in our country. Among them, linear discriminant analysis, logistic regression, decision tree, neural network, and support vector machines are used in this paper. We introduced the basic concepts of above-mentioned classification methods and applied these to the analyses of real data of I city. As a results, five different prediction models are suggested. And also model comparisons are executed by suggesting correct classification rates of the fitted models. To see the applicability of the suggested models for a new data set, simulations are carried out. R packages and programs are used in real data analyses and simulations. Especially, the detailed executing processes by R are provided for the other analyser of related area.

• The Korean Journal of Financial Management
• /
• v.14 no.3
• /
• pp.183-201
• /
• 1997

본 논문은 우리나라의 주가지수수익률의 변동특성이 카오스를 내재하고 있는지 아니면 랜덤과정을 따르는지를 분석하기 위하여 Hurst의 R/S분석을 중심으로 분석하였다. 우리나라 증권시장의 1980년 1월 5일부터 1996년 말까지 총 4,982일 동안의 일별종합주가지수를 대수수익률로 전환한 시계열자료로 R/S분석한 결과 안정성과 주기유무를 판별하는 V-통계량 그래프에 의하면 83일과 33일의 비주기적 순환을 나타내고 있음을 알 수 있었다. 이러한 분석결과는 가우시안 랜덤과정과 그다지 큰 차이가 나지 않음을 알 수 있었다. 또한 선형성을 제거한 ARMA잔차와 비선형성을 제거한 GARCHM잔차자료에 대한 R/S분석한 결과도 원래 시계열보다 더 가우시안 랜덤과정에 더 근접함을 알 수 있었다. 한편 총 10개의 대리자료를 만들어서 평균을 취한 값으로 분석한 결과도 마찬가지로 나타나고 있다. 일별주가지수수익률에 내재하는 선형성분을 ARMA과정에 의정에 제거하고 남은 잔차중에는 비선형성분이 여전히 잔존하는데 그것이 일부 GARCHM과정에 의해서 미미하고 가우시안 랜덤과정이 보다 크게 나타남을 알 수 있었다.