• ETRI Journal
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• 제36권6호
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• pp.1016-1022
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• 2014

This paper presents a hybrid model solution for user motion recognition. The use of a single classifier in motion recognition models does not guarantee a high recognition rate. To enhance the motion recognition rate, a hybrid model consisting of decision trees and artificial neural networks is proposed. We define six user motions commonly performed in an indoor environment. To demonstrate the performance of the proposed model, we conduct a real field test with ten subjects (five males and five females). Experimental results show that the proposed model provides a more accurate recognition rate compared to that of other single classifiers.

• Communications for Statistical Applications and Methods
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• 제13권2호
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• pp.449-466
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• 2006

We propose to use variable selection methods based on penalized regression for pruning decision tree ensembles. Pruning methods based on LASSO and SCAD are compared with the cluster pruning method. Comparative studies are performed on some artificial datasets and real datasets. According to the results of comparative studies, the proposed methods based on penalized regression reduce the size of boosting ensembles without decreasing accuracy significantly and have better performance than the cluster pruning method. In terms of classification noise, the proposed pruning methods can mitigate the weakness of AdaBoost to some degree.

• Journal of the Korean Data and Information Science Society
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• 제23권2호
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• pp.375-383
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• 2012

The purpose of the ensemble methods is to increase the accuracy of prediction through combining many classifiers. According to recent studies, it is proved that random forests and forward stagewise regression have good accuracies in classification problems. However they have great prediction error in separation boundary points because they used decision tree as a base learner. In this study, we use the kernel ridge regression instead of the decision trees in random forests and boosting. The usefulness of our proposed ensemble methods was shown by the simulation results of the prostate cancer and the Boston housing data.

• 아태비즈니스연구
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• 제15권1호
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• pp.145-157
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• 2024

Purpose - In this study, we propose an empirical model for predicting seasoned equity offering (SEO here after) using machine learning methods. Design/methodology/approach - The models utilize the random forest method based on decision trees that considers non-linear relationships, as well as the gradient boosting tree model. SEOs incur significant direct and indirect costs. Therefore, CEOs' decisions of seasoned equity issuances are made only when the benefits outweigh the costs, which leads to a non-linear relationship between SEOs and a determinant of them. Particularly, a variable related to market timing effectively exhibit such non-linear relations. Findings - To account for these non-linear relationships, we hypothesize that decision tree-based random forest and gradient boosting tree models are more suitable than the linear methodologies due to the non-linear relations. The results of this study support this hypothesis. Research implications or Originality - We expect that our findings can provide meaningful information to investors and policy makers by classifying companies to undergo SEOs.

• 대한간호학회지
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• 제51권1호
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• pp.40-53
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• 2021

Purpose: The purpose of this study was to develop and compare the prediction model for suicide attempts by Korean adolescents using logistic regression and decision tree analysis. Methods: This study utilized secondary data drawn from the 2019 Youth Health Risk Behavior web-based survey. A total of 20 items were selected as the explanatory variables (5 of sociodemographic characteristics, 10 of health-related behaviors, and 5 of psychosocial characteristics). For data analysis, descriptive statistics and logistic regression with complex samples and decision tree analysis were performed using IBM SPSS ver. 25.0 and Stata ver. 16.0. Results: A total of 1,731 participants (3.0%) out of 57,303 responded that they had attempted suicide. The most significant predictors of suicide attempts as determined using the logistic regression model were experience of sadness and hopelessness, substance abuse, and violent victimization. Girls who have experience of sadness and hopelessness, and experience of substance abuse have been identified as the most vulnerable group in suicide attempts in the decision tree model. Conclusion: Experiences of sadness and hopelessness, experiences of substance abuse, and experiences of violent victimization are the common major predictors of suicide attempts in both logistic regression and decision tree models, and the predict rates of both models were similar. We suggest to provide programs considering combination of high-risk predictors for adolescents to prevent suicide attempt.

• 한국융합학회논문지
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• 제12권8호
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• pp.39-45
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• 2021

본 논문은 손실값을 포함하는 불완전한 데이터를 처리하는 방법에 대해 논한다. 손실값을 최적으로 처리한다는 것은 학습 데이터가 가지고 있는 정보들에서 본래값과 가장 근사한 추정치를 구하고, 이 값으로 손실값을 대치하는 것이다. 이것을 실현하기 위한 방안으로 분류기가 정보를 분류하는 과정에서 완성되어가는 결정트리를 이용한다. 다시말해 이 결정트리는 전체 학습 데이터 중에서 손실값을 포함하지 않는 완전한 정보만을 C4.5 분류기에 입력하여 학습하는 과정에서 얻어진다. 이 결정트리의 노드들은 분류 변수의 정보를 가지는데, 루트에 가까운 상위 노드일수록 많은 정보를 포함하게 되고 말단 노드에서는 루트로부터의 경로를 통해 분류 영역을 형성하게 된다. 또한 각 영역에는 분류된 데이터 사건들의 평균이 기록된다. 손실값을 포함하는 사건들은 이러한 결정트리에 입력되어 각 노드의 정보에 따라 순회과정을 통해 사건과 가장 근접한 영역을 찾아가게 된다. 이 영역에 기록된 평균값을 손실값의 추정치로 간주하고, 보상 과정은 완성된다.

• 대한간호학회지
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• 제43권3호
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• pp.442-451
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• 2013

Purpose: This descriptive study was done to develop a predictive model of depression in rural elders that will guide prevention and reduction of depression in elders. Methods: A cross-sectional descriptive survey was done using face-to-face private interviews. Participants included in the final analysis were 461 elders (aged${\geq}$ 65 years). The questions were on depression, personal and environmental factors, body functions and structures, activity and participation. Decision tree analysis using the SPSS Modeler 14.1 program was applied to build an optimum and significant predictive model to predict depression in rural elders. Results: From the data analysis, the predictive model for factors related to depression in rural elders presented with 4 pathways. Predictive factors included exercise capacity, self-esteem, farming, social activity, cognitive function, and gender. The accuracy of the model was 83.7%, error rate 16.3%, sensitivity 63.3%, and specificity 93.6%. Conclusion: The results of this study can be used as a theoretical basis for developing a systematic knowledge system for nursing and for developing a protocol that prevents depression in elders living in rural areas, thereby contributing to advanced depression prevention for elders.

• 한국지능시스템학회논문지
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• 제8권6호
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• pp.27-36
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• 1998

본 논문은 대규모 데이터베이스에서 유용한 지식을 발견하기 위해 라프셋을 중심으로 한 통합적 방법을 제시한다. 본 방업에서는 데이터베이스에 있는 실제 데이터에서 일반화된 데이터를 추출하기 위해 속성중심의 개념계층 상승기법을 사용하고, 획득 정보량을 측정하기 위해 결정 트리에 의한 귀납법을 사용한다. 그리고 불필요한 속성 및 속성값을 제거하기 위해 라프셋 이론의 지식감축 방법을 적용한다. 통합 알고리즘은 먼저, 개념의 일반화에 의해 데이터베이스의 크기를 줄이고, 다음으로 결정속성에 영향을 적게 미치는 조건속성을 제거함으로써 속성의 수를 줄인다. 마지막으로 속성간의 종속관계를 분석함으로써 불필요한 속성값을 제거하여 간략화된 결정규칙을 유도한다.

• 대한간호학회지
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• 제50권5호
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• pp.686-698
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• 2020

Purpose: This study was aimed to investigate experiences, perceptions, and educational needs related to patient safety and the factors affecting these perceptions. Methods: Study design was a descriptive survey conducted in November 2019. A sample of 1,187 Koreans aged 20-80 years participated in the online survey. Based on previous research, the questionnaire used patient safety-related and educational requirement items, and the Patient Safety Perception Scale. Descriptive statistics and a decision tree analysis were performed using SPSS 25.0. Results: The average patient safety perception was 71.71 (± 9.21). Approximately 95.9% of the participants reported a need for patient safety education, and 88.0% answered that they would participate in such education. The most influential factors in the group with low patient safety perceptions were the recognition of patient safety activities, age, preference of accredited hospitals, experience of patient safety problems, and willingness to participate in patient safety education. Conclusion: It was confirmed that the vulnerable group for patient safety perception is not aware of patient safety activities and did not prefer an accredited hospital. To prevent patient safety accidents and establish a culture of patient safety, appropriate educational strategies must be provided to the general public.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권1호
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• pp.27-35
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• 2016

Black-box classifiers, such as artificial neural network and support vector machine, are a popular classifier because of its remarkable performance. They are applied in various fields such as inductive inferences, classifications, or regressions. However, by its characteristics, they cannot provide appropriate explanations how the classification results are derived. Therefore, there are plenty of actively discussed researches about interpreting trained black-box classifiers. In this paper, we propose a method to make a fuzzy logic-based classifier using extracted rules from the artificial neural network and support vector machine in order to interpret internal structures. As an object of classification, an anomalous propagation echo is selected which occurs frequently in radar data and becomes the problem in a precipitation estimation process. After applying a clustering method, learning dataset is generated from clusters. Using the learning dataset, artificial neural network and support vector machine are implemented. After that, decision trees for each classifier are generated. And they are used to implement simplified fuzzy logic-based classifiers by rule extraction and input selection. Finally, we can verify and compare performances. With actual occurrence cased of the anomalous propagation echo, we can determine the inner structures of the black-box classifiers.