• Journal of Labour Economics
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• v.25 no.1
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• pp.47-74
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• 2002

Since the Economic Crisis at the end of 1997, unemployment rate soared up to the record-high 8.6% (February 1999) and, for youth aged 15~29, it was 14.6% (27.8% for aged 15~19). In spite of economic recovery after the crisis, new participants in labor market at the school-to-work transition have faced with difficulties in finding their first jobs and, even further, the ratio of youth at out-of the labor force but not in school has remained at a higher level. It is important to calibrate the negative effects of nonemployment in the short-run as well as in the long-run, but there has been few study on the school-to-work transition in Korea. This study focus on the nonemployment duration to first job after formal education and comparison of its pattern before and after the crisis. A proportional hazard model, considering job prenaration before graduation (21.4% of the sample), with the semi-parametric baseline hazard is applied to the sample from the Korean Labor and Income Panel Survey(1998~2000) and its Youth Supplemental survey(2000). Interview of the Survey is conducted, by the Korea Labor Institute, to the same 5,000 household and 13,738 individual sample, guaranteeing nationwide representativeness. The Supplemental Survey consists of 3,302 young individuals aged 15 to 29 at the time of survey and 1,615 of them who are not in school and provide appropriate information is used for the analysis. The empirical results show that there exists negative duration dependence at the first three or for months at the transition period and no duration dependence since a turning point of the baseline hazard rate and that unemployment rate reflecting labor demand conditions has a positive effect on exiting the nonemployment state, which is inconsistent with a theoretical conclusion. Estimation with samples separated by the date of graduation before and after the crisis shows that the effect of unemployment rate on the hazard was negative for the pre-crisis sample but positive for the post-crisis sample.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.206-212
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• 2009

Chemical behaviors of each surface material for interior facilities affect to fire initiation and growth in general fire situation. These chemical behaviors were characterized by thermal properties (Heat release rate, Pyrolysis rate, specific heat, etc) which could be derived from experimental test. Especially, Heat release rate which indicates aspect of fire size is one of the most important property to asses fire hazard and protection needs. The cone calorimeter test (ISO 5660) has recently assumed to a dominant role in bench scale fire testing to obtain the Heat release rate of materials. This value could be calculated by the 'Oxygen Consumption Method' under various producing irradiances to each surface of materials. In this study, Process of the cone calorimeter test was simulated by Pyrolysis model of FDS (Fire Dynamics Simulator by NIST) base on the ISO 5660 international standard. Then, we could estimate the simulation method of FDS in case of single materials through the comparative study with test results.

• Journal of Korean Critical Care Nursing
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• v.3 no.2
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• pp.1-11
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• 2010

Purpose: This study was designed to identify the factors affecting healing of Stage 2 pressure ulcer in an acute care facility in Korea. Methods: 286 Stage 2 pressure ulcers of 145 patients were examined. Data were collected in the period between October $1^{st}$, 2006 and September $30^{th}$, 2007. Data were analyzed with Kaplan-Meier survival analysis for cumulative recovery rate of Stage 2 pressure ulcers. Cox proportional hazard model was used to examine effects of multiple variables simultaneously. Results: Out of 286 initial Stage 2 pressure ulcers, 204 (71.3%) pressure ulcers healed completely. The median time to heal was 15 days according to Kaplan-Meier survival analysis. Cox proportional hazard model showed that the Stage 2 pressure ulcers healed more quickly when pressure redistribution surfaces were used (p<.001, HR=2.184), patients were administered with vitamins (p= .038, HR=1.451), and the size of the pressure ulcers were small (${\leq}3.0cm^2$, p= .006, HR=1.765). Conclusion: The factors contributing to the healing of Stage 2 pressure ulcer in an acute care setting were the application of pressure redistribution surface, small ulcer size (${\leq}3.0cm^2$), and the administration of vitamins.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.87-93
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• 2009

The labyrinth weir can be defined that the plane shape of overflow part is not straight line and is a kind of weir having overflow length increased by changing its plane shape. Recently, the labyrinth weir can be widely applied to various hydraulic facilities such as dam spillway, irrigation facilities, and canal structures by increasing precipitation. This study was performed to analyze the hydraulic characteristics according to triangle labyrinth weir using hydraulic model experiments and finally estimate the discharge coefficients for triangle labyrinth weirs. The formulae of discharge coefficient provided in this study, which make it feasible to calculate the overflow rate by a coefficient of correlation. sum of residuals, MAPE(Mean Absolute Percentage Error), are expected to be widely applied to design of hydraulic facilities such as dam spillway and irrigation system.

• Korean Journal of Social Welfare
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• v.39
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• pp.5-40
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• 1999

Little is known about unemployment duration and re-employment pattern. This paper empirically examines unemployment duration and re-employment pattern using data by the 1998 national survey about the unemployed and their needs. A parametric survival model(Weibull model) is adopted to identify variables predicting unemployment duration. It is found that the data including people without unemployment insurance as well as people with unemployment insurance fit the Weibull model including the hazard distribution that the hazard of reemployment is increasing at an decreasing rate. Variables that affect unemployment duration are age, householdership, family income, size of prior employment organization, and cause of unemployment. In re-employment pattern, statistically significant variables are age, type of prior employment industry, prior employment pattern, and membership in unemployment insurance. This paper provides a basic knowledge about realities of unemployed individuals in the economic crisis period of Korea, identifies research areas for further research, and develops policy implications for the unemployed.

• Korean Journal of Social Welfare
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• v.61 no.3
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• pp.307-328
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• 2009

This study aims to investigate the patterns and causes of the marital duration. Data used for this study are ten waves of Korean Labor and Income Panel Study(KLIPS) in 1998~2007, in which the final sample consists of 2,397 households. The Life-table method is used for describing the overall patterns of marital duration by birth-cohorts and different education groups, and the Cox proportional hazard regression model is used to identify significant factors on the marital duration. The results show that among the all respondents, the 0.79% has divorced or separated within five years after marriage, 2.12% within 10 years, and 5.84% within 20 years, respectively. In addition, the Cox regression results show that the marital duration is significantly affected by the birth-cohorts of respondents and their spouses, education level, earning of spouses, co-residence with parents, and household income. This implies that the hazard rate of marital disruption is higher for younger cohorts, individuals with lower education and economic status, persons living with parents-in-law, compared to their counterparts. Thus, it is necessary to implement social welfare policies applicable for these persons.

• Korea journal of population studies
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• v.32 no.1
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• pp.1-23
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• 2009

This paper uses a survey data to analyze the age-specific fertility rates, age-specific cumulative fertility rates, and ages of marriage of the five birth cohorts of Korean women born in the 1940s and thereafter. It was found that later cohorts reach their highest age-specific fertility rate at higher ages than earlier cohorts. The age-specific cumulative fertility rates of the 1950s and 1960 cohorts were found to be much lower than those of the immediately preceding cohorts, while those of the 1970s and 1980s cohorts were not different from those of the 1960s cohorts. Women belonging to later cohorts were found to get married at relatively higher ages. The estimation results of the hazard model show that women belonging to later cohorts and those with more schooling have a tendency to get married at higher ages. The effect of the birth cohorts is thought to be due to the economic, social, and cultural changes in Korea during the late 50 years or so. The time interval between a woman‘s marriage and first birth was found not to be affected by either the year of marriage or that of her birth. Also, those who remained employed for some time around their marriage and those with low schooling were found to have a lower first child birth hazard, which implies that married women’s employment status and family income play an important role in their decisions on childbirth.

• Journal of Preventive Medicine and Public Health
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• v.39 no.1
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• pp.74-80
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• 2006

Objectives: The purpose of this study is to examine the factors affecting the rate and duration of breastfeeding. Methods: We analyzed the data from the year 2000 Korea National Fertility Survey that was collected through direct interviews. In particular, the mothers who delivered their last child and the child was under 1 year of age from January 1998 to June 2000 (N=1,066) were analyzed via a logistic model to assess the factors affecting the breastfeeding rate. Among the study subjects, those who had initiated breastfeeding (N=740) were analyzed through Cox's proportional hazard model to evaluate the factors affecting the duration of breastfeeding. Results: The multivariate logistic model showed that the delivery type and the baby's birth-weight have a statistically significant influence on the breastfeeding rate. Women who delivered their babies through Cesarean section were less likely than others to breastfeed. In contrast, the women whose babies weighed 2.5Kg or more were more likely than others to breastfeed. The results obtained from the survival analysis are as follows: the higher the mother's education level, the shorter is the breastfeeding duration. The mother's work status played a significant role in the early termination of breastfeeding. Women aged 35 or older showed a longer breastfeeding duration than the younger age groups, whereas the maternal age was not a significant factor in affecting whether or not a mother would breastfeed. Conclusions: Reducing the cases of operative delivery (Cesarean section) and low weight births, enlightening young and highly educated women on breastfeeding and improving the environment for breastfeeding on the job are important strategies to encourage women to breastfeed.

• International Journal of Highway Engineering
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• v.12 no.1
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• pp.61-69
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• 2010

In this paper, we present the methodology about an optimal probability distribution selection as well as survival rate estimation with the national highway database from 1999 to 2008. Probability paper methods are adopted to estimate the parameters of each hazard model. The goodness-of-fit test, such as the Anderson-Darling statistics, was performed. As a result, we found that Lognormal distributionan is an appropriate distribution of newly constructed sections as well as overlayed sections. We also ascertained that the results of survival rate for pavement life between the proposed method and observed data are similar. Such a selection methodology and measures based on reliability theory can provide useful information for maintenance plans in pavement management systems as long as additional life data on pavement sections are accumulated.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.692-700
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• 2022

This study was conducted to analyze firms' death rate and impact factors on the death of Foreign-invested Companies in Korea which is between 20013 and 2017. Cox Proportional Hazard Model took to conduct on the death impact factors, such as 2 characteristics factors of the firm, and 4 financial characteristics variables, variables, and 4 profitability factors. As a result of the impact factors of Foreign-invested Companies' death the Labour(NE) variables of characteristics firm had negative effects. And the Debt(LB), Operating Profit (OP), and Sales Profit (SP) of the financial characteristics had a negative effect. Other factors did not produce significant results. As a result of an empirically comparative analysis of the mortality rate of foreign-invested companies by the Kaplan-Meier method, it was analyzed that fully owned companies and large enterprises had lower extinction risk and greater sustainable management potential than joint ventures or SMEs.