• The Korean Journal of Applied Statistics
• /
• v.22 no.2
• /
• pp.297-307
• /
• 2009

Korean household debt is one of the main sources of the current financial crisis. This paper studies the impact of household members' attributes such as a type of housing(self-own or rent), education, age, average monthly income of the head of household, and the area of residence, on the stress level of the household members due to household debt. We analyze a real data set collected by KB Kookmin Bank in 2004. We consider low and high stress level as a binary response variable and use a logistic regression model with the attributes of household members as explanatory variables. A simple but well-fitting model is selected by backward elimination method based on the likelihood statistic for goodness-of-fit test, and the impact of the attributes on the stress level is studied from parameter estimates of the selected model. We also perform the similar analysis on a binary response variable which distinguishes households with no debt from the rest. From the analysis, the stress level tends to be low for households with self-own houses, high average monthly income, low education level, and young members.

• Journal of Korean Academy of Nursing Administration
• /
• v.6 no.1
• /
• pp.109-122
• /
• 2000

The present study examined the causal relationships among nurses' perceived autonomy, job satisfaction, work environment (work overload, role conflict, situational support, head nurses' leadership), personal aspects(experiences, need for achievement, professional knowledge and skill) by constructing and testing a theoretical framework. Based on literature review nurses' perceived autonomy and job satisfaction were conceived of as outcomes of the interplay among work environment and personal characteristics. Work environment factors involved work overload, role conflict, situational support, and head nurses' leadership (task oriented leadership, relation oriented leadership). Personal charateristics included experiences, need for achievement, and professional knowledge and skill. Three large general hospital in Chonbuk were selected to participate. The total sample of 516 registered nurses represents a response rate of 92 percent. Data for this study was collected from July to September in 1998 by Questionnaire. Path analyses with LISREL 7.16 program were used to test the fit of the proposed conceptual model to the data and to examine the causal relationship among variables. The result showed that both the proposed model and the modified model fit the data excellently. It needs to be notified, however, that path analisis can not count measurement errors; measurement error can attenuate estimates of coefficient and explanatory power. Nevertheless the model revealed relatively high explanatory power. 42 percent of nurses' perceived autonomy was explained by predicted variables; 32 percent of nurses' job satisfaction was explained by by predicted variables. Tn predicting nurses' perceived autonomy the findings of this study clearly demonstrated the work overload might be the most important variable of all the antecedent variables. Head nurses' relation oriented leadership, situational supports, need for achievement, and role conflict were also found to be important determinants for nurses' perceived autonomy. As for the job satisfaction, role conflict, situational supports, need for the achievement, and head nurses' relation oriented leadership were in turn important predictors. Unexpectedly the result showed perceived autonomy have few influence on job satisfaction. The results were discussed, including directions for the future research and practical implication drawn from the research were suggested.

• The Journal of the Korea Contents Association
• /
• v.17 no.11
• /
• pp.479-490
• /
• 2017

The study analyzed the relationship between dating violence and limerence and ruminative response in romentic relationship. The subjects were 205 college students who had experience of dating. And mean age of subjects was 22.1 years. Analysis methods were correlation analysis, ANOVA, two-step cluster analysis, and multinomial logistic regression analysis. The results of this study are as follows. First, self-reproach ruminative respone were significantly higher the victim group and perpetrator victim group than the general group. Second, all sub-factors of ruminative respone were significantly higher the victim group and perpetrator victim group than the general group. Third, the self-reproach ruminative respone was significant positive explanatory variable on dating violence. Fifth, the victim limerence experience significantly increased the odds ratio of victim group of dating violence by 3.3 times, and that of perpetrator victim group of dating violence by 10.9 times. Based on these findings, he discussed the importance of dating violence and the importance of limerence and rumination.

• Journal of Korean Academy of Nursing Administration
• /
• v.13 no.2
• /
• pp.156-166
• /
• 2007

Purpose: The purpose of the present study was to examine the causal relationships among hospital nursing organizational characteristics (organizational climate, workload), individual characteristics (experience, education) and outcome variables (job satisfaction, job stress, task performance) by constructing and testing a conceptual framework. Method: Five large general hospitals located in Seoul were selected to participated. The total sample of 245 registered nurses represents a response rate of 94 percent. Data for this study was collected from January to February in 2006 by questionnaire. Path analyses with LISREL program were used to test the fit of the proposed model to the data and to examine the causal relationships among variables. Result: Both the proposed model and the modified model fit the data excellently. The model revealed relatively high explanatory power of work stress (40%), job satisfaction (46%) and task performance (27%) by predicted variables. In predicting work stress, job satisfaction and task performance, the finding of this study clearly demonstrate organizational climate might be the most important variable. Conclusion: Based on the findings of the study, it was suggested that desirable organizational climate was needed to increase the nurses' mental and physical health as well as qualified task performance.

• The Korean Journal of Applied Statistics
• /
• v.30 no.5
• /
• pp.793-808
• /
• 2017

We compare various variable screening methods on multiclass classification problems when the data is ultrahigh-dimensional. Two different approaches were considered: (1) pairwise extension from binary classification via one versus one or one versus rest comparisons and (2) direct classification of multiclass responses. We conducted extensive simulation studies under different conditions: heavy tailed explanatory variables, correlated signal and noise variables, correlated joint distributions but uncorrelated marginals, and unbalanced response variables. We then analyzed real data to examine the performance of the methods. The results showed that model-free methods perform better for multiclass classification problems as well as binary ones.

• Journal of the Korean Data and Information Science Society
• /
• v.20 no.6
• /
• pp.1093-1101
• /
• 2009

Quantile regression has become a more widely used technique to describe the distribution of a response variable given a set of explanatory variables. This paper proposes a novel modelfor quantile regression using doubly penalized kernel machine with support vector machine iteratively reweighted least squares (SVM-IRWLS). To make inference about the shape of a population distribution, the widely popularregression, would be inadequate, if the distribution is not approximately Gaussian. We present a likelihood-based approach to the estimation of the regression quantiles that uses the asymmetric Laplace density.

• Journal of the Korean Geotechnical Society
• /
• v.36 no.5
• /
• pp.5-16
• /
• 2020

The purpose of this study is to suggest the management criteria through the decision tree analysis for a seepage, which is an important instrumentation type of the fill dam. In the case of the seepage of the dam in Korea, seepage can be increased rapidly because rainfall directly flow into the downstream slope and abutment of dam during rainfalls. Therefore, it is necessary the management criteria for the seepage of the fill dam in consideration of rainfall. In this study, decision tree analysis was performed for a fill dam in Korea by setting the seepage as the response variable and the rainfall and water level of dam as explanatory variables. As the study results, the water level acted as an explanatory variable from the conditions under daily rainfall of 34.75 mm/day, and the branch conditions of the water level were analyzed to be 37.4 m and 35.23 m. 98% of the rainfall data is distributed under the conditions of the daily rainfall of 34.75 mm/day, and coverage of the seepage is indicated from 13.25 L/min to 24.24 L/min. When the rainfall and water level as the influence factors for the seepage were selected, the influence of the rainfall was dominant. Finally, the seepage of fill dam by considering the rainfall and water level was suggested as a management criteria.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2021.11a
• /
• pp.868-871
• /
• 2021

기후, 경영, 경제 등 여러 분야의 회귀분석에서 설명변수가 반응변수에 일정 시차를 두고 영향을 미치는 경우들이 많다. 하지만 지금까지 대부분의 회귀분석은 설명변수가 반응변수에 즉각적으로 영향을 미치는 경우만을 가정하고 있으며, 설명변수와 반응변수 간에 존재하는 시차를 탐색하는 연구는 거의 이루어지지 않았다. 그러나 보다 정확한 회귀분석을 위해서는 설명변수와 반응변수 간에 존재하는 시차를 파악하는 것이 중요하다. 본 논문은 회귀분석 데이터가 주어졌을 때 설명변수와 반응변수 간에 존재하는 시차를 파악하는 딥러닝 모델을 제안한다. 제안하는 딥러닝 모델은 설명변수의 과거 값들 중 어떤 값이 현재 반응변수에 가장 큰 영향을 미치는지를 노드 간 가중치로 표현하고, 회귀모델의 오차를 최소화하는 가중치를 탐색한다. 훈련이 끝나면 이 가중치들을 사용하여 각 설명변수와 반응변수 간에 존재하는 시차를 파악한다. 실험을 통해 제안 방법은 시차를 고려하지 않는 기존 회귀모델에 비해 시차까지 고려함으로써 오차가 1/100 수준에 불과한 더 정확한 회귀모델을 찾을 수 있음을 확인하였다.

• The Korean Journal of Applied Statistics
• /
• v.34 no.3
• /
• pp.375-388
• /
• 2021

This paper aims to help prevent the spread of COVID-19 by analyzing confirmed cases of COVID-19 in Daejeon. A high volume of visitors, downtown areas, and psychological fatigue with prolonged social distancing were considered as risk factors associated with the spread of COVID-19. We considered the weekly confirmed cases in each administrative district as a response variable. Explanatory variables were the number of passengers getting off at a bus station in each administrative district and the elapsed time since the Korean government had imposed distancing in daily life. We employed a mixed-effects zero-inflated Poisson regression model because the number of cases was repeatedly measured with excess zero-count data. We conducted k-means clustering to identify three groups of administrative districts having different characteristics in terms of the number of bars, the population size, and the distance to the closest college. Considering that the number of confirmed cases might vary depending on districts' characteristics, the clustering information was incorporated as a categorical explanatory variable. We found that Covid-19 was more prevalent as population size increased and a district is downtown. As the number of passengers getting off at a downtown district increased, the confirmed cases significantly increased.

• Journal of Korean Academy of Nursing Administration
• /
• v.8 no.4
• /
• pp.551-561
• /
• 2002

Purpose : The purpose of the present study was to examine the causal relationships among head nurses' leadership (consideration oriented leadership, structure initiated leadership), nursing unit culture (human development culture, task development culture), and nurses' organizational commitment. Method : Four large general hospitals located in and around Seoul were selected to participate. The total sample of 286 registered nurses represents a response rate of 90 percent. Data for this study was collected from August to September in 2000 by questionnaire. Path analyses with LISREL program were used to test the fit of the proposed model to the data and to examine the causal relationships among variables. Result : Both the proposed model and the modified model fit the data adequately. The model revealed relatively high explanatory power. 52% of human development culture was explained by predicted variables and 44% of task development was explained by predicted variables; 47% of the organizational commitment was explained by predicted variables. In predicting developmental (both human and task) nursing unit culture, the findings of this study clearly demonstrated that head nurses' consideration oriented leadership might be the most important variable. The result also showed that head nurses' consideration oriented leadership might be the most important variable among the predicted variables in predicting organizational commitment. Conclusion : Based on the findings of this study, it was suggested that various studies, for example, matching leadership and nursing unit culture, were needed.