• Title/Summary/Keyword: The Panel Data Model

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Identifying and Predicting Adolescent Smoking Trajectories in Korea (청소년기 흡연 발달궤적 변화와 예측요인)

  • Chung, Ick-joong
    • Korean Journal of Social Welfare Studies
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    • no.39
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    • pp.5-28
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    • 2008
  • The purpose of this study is two-fold: 1) to identify different adolescent smoking trajectories in Korea; and 2) to examine predictors of those smoking trajectories within a social developmental frame. Data were from the Korea Youth Panel Survey(KYPS), a longitudinal study of 3,449 youths followed since 2003. Using semi-parametric group-based modeling, four smoking trajectories were identified: non initiators, late onsetters, experimenters, and escalators. Multinomial logistic regressions were then used to identify risk and protective factors that distinguish the trajectory groups from one another. Among non smokers at age 13, late onsetters were distinguished from non initiators by a variety of factors in every ecological domain. Among youths who already smoked at age 13, escalators who increased their smoking were distinguished from experimenters who almost desisted from smoking by age 17 by self-esteem and academic achievement. Finally, implications for youth welfare practice from this study were discussed.

Review of Policy Direction and Coupled Model Development between Groundwater Recharge Quantity and Climate Change (기후변화 연동 지하수 함양량 산정 모델 개발 및 정책방향 고찰)

  • Lee, Moung-Jin;Lee, Joung-Ho;Jeon, Seong-Woo;Houng, Hyun-Jung
    • Journal of Environmental Policy
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    • v.9 no.2
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    • pp.157-184
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    • 2010
  • Global climate change is destroying the water circulation balance by changing rates of precipitation, recharge and discharge, and evapotranspiration. The Intergovernmental Panel on Climate Change (IPCC 2007) makes "changes in rainfall pattern due to climate system changes and consequent shortage of available water resource" a high priority as the weakest part among the effects of human environment caused by future climate changes. Groundwater, which occupies a considerable portion of the world's water resources, is related to climate change via surface water such as rivers, lakes, and marshes, and "direct" interactions, being indirectly affected through recharge. Therefore, in order to quantify the effects of climate change on groundwater resources, it is necessary to not only predict the main variables of climate change but to also accurately predict the underground rainfall recharge quantity. In this paper, the authors selected a relevant climate change scenario, In this context, the authors selected A1B from the Special Report on Emission Scenario (SRES) which is distributed at Korea Meteorological Administration. By using data on temperature, rainfall, soil, and land use, the groundwater recharge rate for the research area was estimated by period and embodied as geographic information system (GIS). In order to calculate the groundwater recharge quantity, Visual HELP3 was used as main model for groundwater recharge, and the physical properties of weather, temperature, and soil layers were used as main input data. General changes to water circulation due to climate change have already been predicted. In order to systematically solve problems associated with how the groundwater resource circulation system should be reflected in future policies pertaining to groundwater resources, it may be urgent to recalculate the groundwater recharge quantity and consequent quantity for using via prediction of climate change in Korea in the future and then reflection of the results. The space-time calculation of changes to the groundwater recharge quantity in the study area may serve as a foundation to present additional measures for the improved management of domestic groundwater resources.

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Estimating the Determinants of Loan Amount of Housing Mortgage : A Panel Data Model Approach (주택 담보 가계 대출액 결정요인 추정에 관한 패널 데이터 모형 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.7
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    • pp.183-190
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    • 2011
  • Loan amount of housing mortgage is composed of various factors. This study paper studies focuses on estimating the determinants of a loan amount of housing mortgage. The region for analysis consist of seven groups, that is, metropolitan city (such as Busan, Daegu, Incheon, Gwangiu, Daejeon, Ulsan.) and Seoul. Analyzing period be formed over a 45 time points(2007. 01.~ 2010. 09). In this paper the dependent variable setting up loan amount of housing mortgage, explanatory(independent) variables are composed of the consumer price index, unemployment rate, average monthly household income per household, expenditure rate of health care, composite stock price index and overdue rate of household loans for commercial bank. In looking at the factors which determine loan amount of housing mortgage, evidence was produced supporting the hypothesis that there is a significant positive relationship between the consumer price index and unemployment rate. The study also produced evidence supporting the view that there is a significant negative relationship between expenditure rate of health care. The study found that average monthly household income per household, expenditure, composite stock price index and overdue rate of household loans for commercial bank were not significant variables. The implications of these findings are discussed for further research.

The Effect of Child Neglect and Abuse by Parents on School Adjustment of School-Aged Children : The Mediating Effects of Self-Awareness and Peer Attachment (부모의 방임·학대가 학령기 아동의 학교생활적응에 미치는 영향: 학령기 아동의 자아인식과 또래애착의 매개효과)

  • Kim, Hye Gum;Jo, Hye Young
    • Korean Journal of Childcare and Education
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    • v.12 no.1
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    • pp.19-36
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    • 2016
  • The purpose of the present study was to investigate the effect of child neglect and abuse by parents on school adjustment of school-aged children focusing on mediating effect of school-aged children's self-awareness and peer attachment. For this purpose, we analyzed the data of fourth wave Korean Child-Youth Panel Survey(KCYPS) including parents' child neglect and abuse, school-aged children's school adjustment, self-awareness and peer attachment. A total of 2,378 children and their parents using structural equation model of mediating effects responded to the survey. Measurement model and structure model had favorable goodness of fit and the results of structure models on each path were as follows. First, school-aged children's school adaption had negative correlations with parent's child neglect and abuse, but positive correlations with their self-awareness and peer attachment. Second, parent's child neglect and abuse influenced on school-aged children's school adjustment by partial mediators, their self-awareness and peer attachment. These findings showed practical way to increase school-aged children's self-awareness and positive peer attachment.

Predictors of Deviant Self-Concept in Adolescence and Gender Differences: Applying a Latent-State Trait Autoregressive Model (청소년기 일탈적 자아개념의 예측 요인과 성별 차이 : 잠재 상태-특성 자기회귀 모델 (latent state-trait autoregressive model)의 적용)

  • Lee, Eunju;Chung, Ick-Joong
    • Korean Journal of Social Welfare Studies
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    • v.43 no.1
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    • pp.5-29
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    • 2012
  • The present study was to explore what makes adolescents think of themselves as troublemakers even without conduct problems. It was expected that the failure to attain socio-developmental milestones(e.g., healthy relationships with others, academic achievement) would lead to form trait aspect of deviant self-concept. A latent state-trait autoregressive modeling was used to analyze five annual waves of data from 3,449 adolescents taken from the Korean Youth Panel Study. We decomposed trait and state aspect of deviant self-concept and identified significant predictors of trait-like deviant self-concept, while additionally testing for gender differences. Our results showed that conduct problems had greater effect on deviant self-concept among girls compared with boys. Conduct problem was most predictive of deviant self-concept, and yet both poor peer-relations and school failures predisposed adolescents to have deviant self-concept. Low academic achievement conferred risk for trait aspects of deviant self-concept with no gender difference, whereas poor peer relation was more predictive among girls. It highlights the cultural value system underlying self-concept and how and why adolescents think of themselves as troublemakers.

Applicability of Artificial Intelligence Techniques to Forecast Rainfall and Flood Damage in Future (미래 강우량 및 홍수피해 전망을 위한 인공지능 기법의 적용성 검토)

  • Lee, Hoyong;Kim, Jongsung;Seo, Jaeseung;Kim, Sameun;Kim, Soojun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2021.06a
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    • pp.184-184
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    • 2021
  • 2020년의 경우 대기 상층 제트기류가 크게 강화됨에 따라 작은 규모의 저기압의 발달이 평년보다 두 배 이상 증가하였고, 그로 인해 장마가 최대 54일가량 지속되며 1조 371억 원 가량의 대규모 침수피해가 발생하였다. 이와 같이 최근 기후변화로 인한 이상 기후가 빈번하게 발생하고 있으며, 그로 인해 홍수, 태풍과 같은 재난의 강도 및 파급되는 재산피해가 점차 증가하고 있는 추세이다. 따라서 본 연구에서는 기후변화를 고려하여 향후 30년간 강우량 변화 추이를 파악하고, 이에 따라 파급되는 재난피해 규모의 증가 추세를 확인하고자 하였다. 기후변화 시나리오는 IPCC AR6(Intergovernmental Panel on Climate Change - Sixth Assessment Report)에서 제시하고 있는 시나리오 중 극한 시나리오인 SSP5-8.5와 안정화 시나리오인 SSP2-4.5 시나리오를 활용하고자 하였다. GCM(General Circulation Model) 자료는 전 지구적 모형으로 공간적 해상도가 낮은 문제가 있기 때문에, 국내 적용을 위해서는 축소기법을 적용해야 한다. 본 연구에서는 공간적 축소를 위해 통계학적 기법 중 인공지능 기법을 적용하고 Reference data와 종관기상관측(ASOS)의 실측 강우 자료(1905 ~ 2014년)를 통해 학습된 모형의 정확도 검증을 수행하였다. 또한 연 강수량과 연도별 홍수피해의 규모 및 빈도를 확인하여 연도별 강수량 증가에 따른 피해 규모의 증가를 관계식을 도출하였다. 이후 최종적인 축소기법으로 모형을 통해 향후 2050년까지 부산광역시의 예측 강우량을 전망하여 연 강수량의 증가량과 피해 규모의 증가량을 전망해보고자 하였다. 본 연구 결과는 부산광역시의 예방단계 재난관리의 일환으로 적응형 기후변화 대책 수립에 기초 자료로써 활용될 수 있을 것이다.

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Stiffness Enhancement of Piecewise Integrated Composite Robot Arm using Machine Learning (머신 러닝을 이용한 PIC 로봇 암 강성 향상에 대한 연구)

  • Ji, Seungmin;Ham, Seokwoo;Cheon, Seong S.
    • Composites Research
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    • v.35 no.5
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    • pp.303-308
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    • 2022
  • PIC (Piecewise Integrated Composite) is a new concept for designing a composite structure with mosaically assigning various types of stacking sequences in order to improve mechanical properties of laminated composites. Also, machine learning is a sub-category of artificial intelligence, that refers to the process by which computers develop the ability to continuously learn from and make predictions based on data, then make adjustments without further programming. In the present study, the tapered box beam type PIC robot arm for carrying and transferring wide and thin LCD display was designed based on the machine learning in order to increase structural stiffness. Essential training data were collected from the reference elements, which were intentionally designated elements among finite element models, during preliminary FE analysis. Additionally, triaxiality values for each finite element were obtained for judging the dominant external loading type, such as tensile, compressive or shear. Training and evaluating machine learning model were conducted using the training data and loading types of elements were predicted in case the level accuracy was fulfilled. Three types of stacking sequences, which were to be known as robust toward specific loading types, were mosaically assigned to the PIC robot arm. Henceforth, the bending type FE analysis was carried out and its result claimed that the PIC robot arm showed increased stiffness compared to conventional uni-stacking sequence type composite robot arm.

Private Income Transfers and Old-Age Income Security (사적소득이전과 노후소득보장)

  • Kim, Hisam
    • KDI Journal of Economic Policy
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    • v.30 no.1
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    • pp.71-130
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    • 2008
  • Using data from the Korean Labor & Income Panel Study (KLIPS), this study investigates private income transfers in Korea, where adult children have undertaken the most responsibility of supporting their elderly parents without well-established social safety net for the elderly. According to the KLIPS data, three out of five households provided some type of support for their aged parents and two out of five households of the elderly received financial support from their adult children on a regular base. However, the private income transfers in Korea are not enough to alleviate the impact of the fall in the earned income of those who retired and are approaching an age of needing financial assistance from external source. The monthly income of those at least the age of 75, even with the earning of their spouses, is below the staggering amount of 450,000 won, which indicates that the elderly in Korea are at high risk of poverty. In order to analyze microeconomic factors affecting the private income transfers to the elderly parents, the following three samples extracted from the KLIPS data are used: a sample of respondents of age 50 or older with detailed information on their financial status; a five-year household panel sample in which their unobserved family-specific and time-invariant characteristics can be controlled by the fixed-effects model; and a sample of the younger split-off household in which characteristics of both the elderly household and their adult children household can be controlled simultaneously. The results of estimating private income transfer models using these samples can be summarized as follows. First, the dominant motive lies on the children-to-parent altruistic relationship. Additionally, another is based on exchange motive, which is paid to the elderly parents who take care of their grandchildren. Second, the amount of private income transfers has negative correlation with the income of the elderly parents, while being positively correlated with the income of the adult children. However, its income elasticity is not that high. Third, the amount of private income transfers shows a pattern of reaching the highest level when the elderly parents are in the age of 75 years old, following a decreasing pattern thereafter. Fourth, public assistance, such as the National Basic Livelihood Security benefit, appears to crowd out private transfers. Private transfers have fared better than public transfers in alleviating elderly poverty, but the role of public transfers has been increasing rapidly since the welfare expansion after the financial crisis in the late 1990s, so that one of four elderly people depends on public transfers as their main income source in 2003. As of the same year, however, there existed and occupied 12% of the elderly households those who seemed eligible for the National Basic Livelihood benefit but did not receive any public assistance. To remove elderly poverty, government may need to improve welfare delivery system as well as to increase welfare budget for the poor. In the face of persistent elderly poverty and increasing demand for public support for the elderly, which will lead to increasing government debt, welfare policy needs targeting toward the neediest rather than expanding universal benefits that have less effect of income redistribution and heavier cost. Identifying every disadvantaged elderly in dire need for economic support and providing them with the basic livelihood security would be the most important and imminent responsibility that we all should assume to prepare for the growing aged population, and this also should accompany measures to utilize the elderly workforce with enough capability and strong will to work.

A Review on the Contemporary Changes of Capital Structures for the Firms belonging to the Korean Chaebols (한국 재벌기업들의 자본구조변화 추이에 관한 재무적 관점에서의 고찰)

  • Kim, Hanjoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.1
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    • pp.86-98
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    • 2014
  • This study examined a long-standing issue with its perverse results in the Korean capital markets, such as any variant financial profiles over time, affecting capital structure for the firms belonging to the chaebols. It may be of interest to identify these components from the perspectives of international investors and domestic policy makers to implement their contingent strategies on the target leverage, since the U.S. financial turmoils in the late 2000s. Regarding the evidence from the three hypothesis tests on the firms in the chaebols, this research found that the control variabels measuring profitability, business risk, and non-debt tax shields, showed their statistically significant relationships with the different types of a debt ratio. While FCFF(free cash flow to the firm) showed its significant influence to discriminate between the firms in the chaebols and their counterparts, not belonging to the chaebols, BDRELY as the ratio of liabilities to total assets, comprising the enhanced 'Dupont' system, only showed its statistically significant effect on leverage in the context of the parametric and nonparametric tests. In line with the results obtained from the present research, one may expect that a firm in the Korean chaebol, may control or restructure its present level of capital structure to revert to its target optimal capital structure towards maximizing the shareholders' wealth.

A Longitudinal Causal Rrelationship Study on the Elderly's Assets, Depression and Llife Satisfaction: : The Application of Autoregressive Cross-lagged Model (노인의 자산과 우울 및 삶의 만족 간의 종단적 인과관계: 자기회귀교차지연모형의 적용)

  • Lee, Hyoung-Ha
    • Journal of Digital Convergence
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    • v.18 no.6
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    • pp.513-522
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    • 2020
  • The purpose of this study is to analyze the auto-regression effect between the elderly's assets and depression and life satisfaction, and to approach the influence of assets and depression on the elderly's life from a longitudinal perspective. For this purpose, the data for the 9th year (2014), 11th year (2016), and 13th year (2018) of the Korea Welfare Panel were used. As a result of the analysis, First, the assets, depression and life satisfaction of the elderly have a lasting effect on the passage of time, and the assets, depression and life satisfaction of the previous point in time (B=.694, B=.725, p<.001), depression (B=.258, B=.331 and p<.001) and life satisfaction (B=.264, B=.265, p<.001). Second, cross-recursion coefficients show how the relationship between the assets of the elderly and depression and the satisfaction of life affects each other over time, and the assets of the older person at the previous point in time (B=.010, B=.011, p<.001), the assets of the older persons at previous times are subsequently satisfied with their lives (B=.128, B=.124, p<.001). Based on the results of the above analysis, it is necessary to support the elderly's asset management service and education to prevent depression, such as continuous asset utilization education.