• Korean Journal of Child Studies
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• v.28 no.2
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• pp.217-233
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• 2007

The present study investigated the effects of individual, family, school, and community factors on the onset of adolescent runaway behavior. Using the Korean Youth Panel data(n=3,118), discrete-time survival analysis was applied for research purposes. Results showed that the likelihood of onset of adolescent runaway behavior increased sharply during the early middle school years. The variables of self-control, aggression, parents' divorce, paternal abuse, attachment with parents, and number of delinquent peers were associated with the likelihood of runaway behavior. These results suggest that special attention should be paid to adolescents in the early middle school years and that various preventive programs, e.g., aggression and stress management, and peer relations programs, should be developed and implemented.

• Survey Research
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• v.11 no.3
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• pp.81-101
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• 2010

The purposes of the present study were to investigate the effects of individual, family, and school factors on the onset of adolescents' violence behaviors. For these goals, we applied discrete-time survival analysis to the Korean Youth Panel Survey. According to the estimated hazard function, the likelihood of onset of adolescents' violence behavior was low during elementary school years and increasing sharply from middle school years. Results showed that gender, self-esteem, aggressiveness, broken home, parental abuse, and the number of delinquent friends were significant determinants of the onset of adolescents' violence behaviors. Findings from this study suggest the need to focus on the significant determinants and consider various prevention programs.

• Journal of Preventive Medicine and Public Health
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• v.56 no.1
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• pp.59-66
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• 2023

Objectives: The aim of this study was to evaluate the effect of body weight status and sleep duration on the discrete-time hazard of menarche in Korean schoolgirls using multiple-point prospective panel data. Methods: The study included 914 girls in the 2010 Korean Children and Youth Panel Study who were in the elementary first-grader panel from 2010 until 2016. We used a Gompertz regression model to estimate the effects of weight status based on age-specific and sex-specific body mass index (BMI) percentile and sleep duration on an early schoolchild's conditional probability of menarche during a given time interval using general health condition and annual household income as covariates. Results: Gompertz regression of time to menarche data collected from the Korean Children and Youth Panel Study 2010 suggested that being overweight or sleeping less than the recommended duration was related to an increased hazard of menarche compared to being average weight and sleeping 9 hours to 11 hours, by 1.63 times and 1.38 times, respectively, while other covariates were fixed. In contrast, being underweight was associated with a 66% lower discrete-time hazard of menarche. Conclusions: Weight status based on BMI percentiles and sleep duration in the early school years affect the hazard of menarche.

• Communications for Statistical Applications and Methods
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• v.7 no.2
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• pp.605-616
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• 2000

Three primary interests frequently raised by mortgage companies are introduced and the corresponding statistical approaches for the default probability in mortgage companies are examined. Statistical models considered in this paper are time series, logistic regression, decision tree, neural network, and discrete time models. Usage of the models is illustrated using an artificially modified data set and the corresponding models are evaluated in appropriate manners.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.459-467
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• 2021

This study examined the onset of adolescent delinquency through discrete-time survival analysis. Our analysis used data obtained from the Korean Children & Youth Panel Survey, and included 2,277 middle school students. The main analysis results are as follows. First, the hazard probability for the occurrence of delinquency was the highest at 16.6% in the second year of middle school, slightly decreased in the third year of middle school, but continued to increase as the overall grade increased. Second, adolescent psychological and emotional factors have significantly affected the onset of delinquency. Third, negative parenting methods had a significant impact on delinquency, but neglect was not significant. Fourth, having delinquent friends was an important factor affecting the status of delinquency. Fifth, among the school factors, adjustment of learning activities, adjustment of school rules, and adjustment of friendship relations influenced the status of delinquency, while the adjustment of teacher relations was not significant. As early intervention is important to prevent juvenile delinquency, education and support for establishing healthy relationships are needed.

• Journal of the Korean Statistical Society
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• v.36 no.2
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• pp.321-333
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• 2007

In the proportional hazard model with the beta process prior, the posterior computation with the discrete approximation is considered. The time period of interest is partitioned by small intervals. On each partitioning interval, the likelihood is approximated by that of a binomial experiment and the beta process prior is by a beta distribution. Consequently, the posterior is approximated by that of many independent binomial model with beta priors. The analysis of the leukemia remission data is given as an example. It is illustrated that the length of the partitioning interval affects the posterior and one needs to be careful in choosing it.

• Journal of Labour Economics
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• v.38 no.4
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• pp.57-81
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• 2015

In this paper we try to explain delays in one's first marriage that are observed in contemporary society by accounting for possible factors that may play a substantial role in delaying marriages. Discrete-time survival analysis with unobserved heterogeneity was employed. The result indicates that the odds of getting married compared to odds of not getting married are 0.91 times, i.e. 8.5% lower for women with bachelor's degree than women with high school diploma or below. The odds of getting married compared to odds of not getting married are 0.4 times, i.e. 59.6% lower in case of women with masters and/or doctorate program degree than women with bachelor's degree. Employed men's odds of getting married to not getting married are increased by a factor of 1.65 compared to the unemployed men. In addition, if one's family circumstances are economically below average at the age of 14, the odds decrease by a multiple of 0.65. With these results, we are able to conclude that not only education level but also one's economic ability play significant roles in determining one's marriage decision.

• Land and Housing Review
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• v.13 no.2
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• pp.91-115
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• 2022

This study examines changes in business survival rates in a gentrified commercial district by comparing early movers with late entrants. Using the Hongik University Commerical District, or Hongdae, as a case study, we adopt discrete-time survival analysis to compare survival rates between businesses established before 2000 (early movers) and ones established after 2000 (late arrivers). We compare the business survival patterns in a gentrified commercial district (experimental group) to non-gentrified commercial districts (control group) in Mapogu. We examine a survival-rate difference between early movers and late arrivers by different industrial categories. We finally examine a survival-rate gap between franchise and non-franchised businesses. The results show that the early movers have lower survival rates than the late arrivers in the gentrified Hongdae area, whereas there is no significant difference in survival rates between the early movers and the late arrivers in Mapogu. The early movers in daily-life-supporting businesses in Mapogu have even higher survival rates than the late-arrivers. In addition, franchised businesses have higher survival rates than non-franchised stores both in Hongdae and Mapogu. The results provide statistical and comprehensive evidence of the displacement of early movers at a more rapid pace in gentrified areas than non-gentrified aveas, which has been an anecdotal narrative.

• Journal of Korean Academy of Nursing
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• v.51 no.1
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• pp.54-67
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• 2021

Purpose: The aim of this study was threefold, to longitudinally examine the risk of habitual smoking onset in adolescents, to delineate the effects of neighborhood characteristics and friends' smoking status on the habitual smoking onset, and to investigate whether the association between friends' smoking status and habitual smoking onset was moderated by neighborhood characteristics. Methods: This study conducted multilevel discrete-time survival analysis, using cohort data from the 3rd to 6th waves of the Korean Child and Youth Panel Survey, which excluded habitual smokers, matched with 2010 census data on respondents' residence. Results: Habitual smoking onset risk increased from the 8th to the 11th grade, and then slightly decreased from the 11th to the 12th grade. Friends' smoking status (B = 0.60, p < .001), smoking rate (B = 0.06, p = .038), and the number of tobacco outlets in the respondents' neighborhood (B = 0.51, p = .003) were positively associated with habitual smoking onset risk. Furthermore, the association between friends' smoking status and habitual smoking onset risk was moderated by the number of tobacco outlets in the neighborhood. Specifically, the association was stronger in neighborhoods with more tobacco outlets (B = 0.58, p = .048). Conclusion: Friends' smoking status and living in neighborhoods that are more susceptible to smoking increase the risk of habitual smoking. The number of tobacco outlets in the neighborhood enhances the peer effect of adolescent's smoking behavior. Therefore, policies or interventions designed to reduce youth's tobacco use should focus on not only on reducing peer smoking, but also restricting smoking by adults and the number of neighborhood tobacco outlets.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.6
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• pp.59-76
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• 2019

Most technology-based entrepreneurship(TBE) go through an process of decline or disappear without overcoming the valley of death(VoD). The purpose of this study is to identify the growth dimension of TBE and to test the influence of firms activities on firms growth over time. This study identified the two-dimensional growth dimension divided by size and profit through exploratory factor analysis(EFA) of a number of growth indicators. Then, we defined the discrete state of growth firm in four states, divided by size and profit, and five states, including the closure of business. Multi-nomial logit model is used to predict the effect of TBE activities on a discrete state of growth firm(size×profit, closure of business) based on multiple independent variables. The independent variables are based on five representative firms activities: employment, marketing, R&D, financial activities, and general management activities. The growth stage of TBE over time has been categorized into three stages: early stage, middle stage, and late stage of business, taking into account the main periods during which the survival rate of startups sharply decreases. The analytical data of this study was based on the secondary data of the start-up supporting companies of government and public institutions. The subjects of analysis were TBE within 10 years. As a result of the empirical analysis, the employment and marketing activities of TBE show that early and mid-term activities had an effect on the state of firms growth. However, if there is a difference, employment activities have both positive and negative effects, while marketing activities have only a positive effect on size and profit growth. And besides, R&D activities, financial activities, and general management activities throughout the entire process of firms growth were found to be firms activities that have both positive and negative effects on firms growth. In addition, the age of the founder, the firms' industry, and the geographic location of the firms, which are general characteristics of the company, were found to have a distinctive effect on the growth status of the firms according to the growth stage.