• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.195-198
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• 2004

One Important problem in a cancer microarray study is to identify a set of genes from which a molecular prognostic indicator can be developed. In parallel with this problem is to validate the chosen set of genes. We develop in this note a K-fold cross validation procedure by combining a 'pre-validation' technique and a bootstrap resampling procedure in the Cox regression . The pre-validation technique predicts the microarray predictor of a case without having seen the true class level of the case. It was suggested by Tibshirani and Efron (2002) to avoid the possible over-fitting in the regression in which a microarray based predictor is employed. The bootstrap resampling procedure for the Cox regression was proposed by Sauerbrei and Schumacher (1992) as a means of overcoming the instability of a stepwise selection procedure. We apply this K-fold cross validation to the microarray data of 92 gastric cancers of which the experiment was conducted at Cancer Metastasis Research Center, Yonsei University. We also share some of our experience on the 'false positive' result due to the information leak.

• The Korean Journal of Applied Statistics
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• v.7 no.1
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• pp.149-158
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• 1994

Nonparametric regression technique using kernel estimator is an attractive alternative that has received some attention, recently. The kernel estimate depends on two quantities which have to be provided by the user : the kernel function and the bandwidth. However, the more difficult problem is how to find an appropriate bandwidth which controls the amount of smoothing (see Silverman, 1986). Thus, in practical situation, it is certainly desirable to determine an appropriate bandwidth in some automatic fashion. Thus, the problem is to find a data-driven or adaptive (i.e., depending only on the data and then directly computable in practice) bandwidth that performs reasonably well relative to the best theoretical bandwidth. In this paper, we introduce a relation between bias and variance of mean square error. Thus, we present a simple and effective algorithm for selecting local bandwidths in kernel regression.

• Journal of Families and Better Life
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• v.24 no.2 s.80
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• pp.93-106
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• 2006

This study investigated the determinants of Tap Water consumption patterns. Socio-demographic variables(gender, family income, education level, residual area) and consumer attitude knowledge(confidence, knowledge, problem experience, risk perception and aesthetic satisfaction)were included in the analysis. Three hundred fifty-nine teachers were participated in this study. ANOVA(Scheffe test), t-test, regression and logistic regression were conducted. The results of this study are as follows: 1. Tap water was consumed by only 1.7%, boiled water prior to drinking by 37.9%, water filtered by 39.8% and bottled water by 19.0%. 2. Consumer attitude knowledge was affected by socio-demographic variables. That is, aesthetic satisfaction was affected by age, risk perception by gender and educational level, confidence by educational level, knowledge by gender and age, and problem experience by age. 3. Logistic regression analysis indicated that age, confidence and aesthetic satisfaction were the determinants of bottled water or filtered water choice. However, risk perception was not a significant determinant. This suggests alternatives to tap water is related to non-risk, or non-safety factors.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.480-486
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• 2007

The subway is a necessary public transportation in big cities, which many citizens are using now. However, the demands for subway inner circumstance by citizens are growing recently. Among them, the noise problem is the hot issue to be solved. So, in this study we classified the characteristics of subway noise using the classification and regression trees (CART) based on noise level data in line No. 5 in Seoul. After that We developed the models for effect of subway noise and analyzed the characteristics through it. The result of this study is that we need to consider the type of geometry design and operational factors when the problem of subway noise improves, because the factors which weigh with subway noise are different by type of geometry and operational part.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.5
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• pp.253-263
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• 2021

Traffic data collected using advanced equipment are highly valuable for traffic planning and efficient road operation. However, there is a problem regarding the reliability of the analysis results due to equipment defects, errors in the data aggregation process, and missing data. Unlike other detectors installed for each vehicle lane, radar detectors can yield different error types because they detect all traffic volume in multilane two-way roads via a single installation external to the roadway. For the traffic data of a radar detector to be representative of reliable data, the error factors of the radar detector must be analyzed. This study presents a field survey of variables that may cause errors in traffic volume collection by targeting the points where radar detectors are installed. Video traffic data are used to determine the errors in traffic measured by a radar detector. This study establishes three types of radar detector traffic errors, i.e., artificial, mechanical, and complex errors. Among these types, it is difficult to determine the cause of the errors due to several complex factors. To solve this problem, this study developed a radar detector traffic volume error analysis model using a multiple linear regression model. The results indicate that the characteristics of the detector, road facilities, geometry, and other traffic environment factors affect errors in traffic volume detection.

• Korean Journal of Child Education & Care
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• v.18 no.2
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• pp.117-127
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• 2018

The purpose of this study was to analyze the relationships among mother's depression, parenting behavior of children's problem behavior. The subjects used in this study were 203 three to five-year-old children who attended kindergarten and deycare center in Seoul and Gyonggido. The research data were collected through the 'Beck Depression Inventory(BDI)', 'Maternal Behavior Research Instrument(MBRI)', 'K-CBCL'. The data were analyzed by Pearson's correlation and Stepwise Multi-Regression. The results of this study indicate that there were significant positive correlations among children's problem behavior, mother's depression, rejective and control parenting behavior. And there were significant negative correlations among children's problem behavior, mother's affectionate and permissive parenting behavior. Also, the mother's depression was the predicted variable that has the most significant relative effect on children's problem behavior. Moreover, the results of this study indicate that rejective parenting behavior that is subordinate factor of parenting behavior was additional predictor of stress.

• Convergence Security Journal
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• v.13 no.2
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• pp.175-183
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• 2013

This study determined the correlation between College Life in Freshmen critical thinking disposition; problem solving process. It also examined the impact of critical thinking disposition on problem solving process. The data was collected from 215 Freshmen members. Descriptive statistics, t-test, ANOVA, scheffe test, pearson correlation analysis and multiple regression analysis were performed. Results: In critical thinking disposition, there were significants differences in age, interpersonal relationships. In multiple regression analysis, critical thinking disposition and major satisfaction were significants factors of problem process ability explaining 38% Conclusion: To enhance problem process ability for freshmen, it is necessary to develop teaching program and curriculum.

• Korean Journal of Childcare and Education
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• v.9 no.1
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• pp.175-200
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• 2013

This study focused on the relationships among teachers'playfulness, teachers'positive play beliefs, teaching efficacy on play and teacher's strategies of problem behavior guidance, and especially the mediating effects of teaching efficacy on children's play. Subjects were 151 early childhood teachers in Seoul and Chungcheungnam-do. The collected data were analyzed using simple regression, hierarchical multiple regression and the Sobel test. The main results of this study were as follows. First, teachers' playfulness and teachers'positive play beliefs had a positive influence on their proactive, positive reactive strategies of problem behaviors. On the other hand, teachers' positive play beliefs had a negative influence on their negative reactive strategies of problem behaviors. Second, teachers' playfulness and teachers'positive play beliefs had a positive influence on their teaching efficacy on play. Finally, the effects of teachers' playfulness on their proactive, positive reactive strategies of problem behaviors of preschoolers were totally mediated by their teaching efficacy on play.

• Korean Journal of Childcare and Education
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• v.13 no.3
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• pp.83-102
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• 2017

Objective: This study investigates the main effects and interaction effects of mother's reactions to young children's negative emotions on the children's problem behaviors. Methods: A total of 346 mothers with toddlers completed questionnaires, the data were analyzed using Pearson's correlation coefficient and multiple regression. Results: First, mothers' supportive response to young children's negative emotions, including expressive encouragement, emotion-focused reactions, and problem-focused reactions, showed negative relations with the children's internal and external problem behaviors. Mothers' unsupportive response to children's negative emotions, including distress reactions, minimization reactions, and punitive reactions, showed positive relations with the children's internal and external problem behaviors. Second, an interactive effect was observed. For external problem behavior, mothers' lower distress reactions accompanied by higher emotion-focused reactions, lower punitive reactions accompanied by higher emotion-focused reactions, lower distress reactions accompanied by higher problem-focused reactions, and lower punitive reactions accompanied by higher problem-focused reactions all decreased children′s problem behavior. However, for internal problem behavior, only mothers' lower distress reactions accompanied by higher emotion-focused reaction decreased children′s problem behavior. Conclusion/Implication: The main interaction effect on mothers' reaction to young children's negative emotional expression shows that preventive intervention is needed to address problem behavior.

• Korean Journal of Child Studies
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• v.28 no.6
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• pp.169-182
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• 2007

Creative problem solving skills in mathematics were measured by fluency, flexibility, and originality; cognitive strategies were measured by rehearsal, elaboration, organization, planning, monitoring, and regulating. The Creative Problem Solving Test in Mathematics developed at the Korea Educational Development Institute(Kim et al., 1997) and the Motivated Strategies for Learning Questionnaire(Pintrich & DeGroot, 1990) were administered to 84 subjects in grade 5(45 girls, 39 boys). Data were analyzed by Pearson's correlation, multiple regression analysis, and canonical correlation analysis. Results indicated that positive regulating predicted total score and fluency, flexibility, and originality scores of creative problem solving skills. Elaboration, rehearsal, organization, regulating, monitoring, and planning positively contributed to the fluency and flexibility scores of creative problem solving skills.