• 한국해양공학회지
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• 제15권1호
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• pp.1-6
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• 2001

This study focuses on the potential flow analysis for a hull with the transom stern. The method is based on a low order panel method. The Kelvin type free-surface boundary condition which is known to better fit experimental data for a high speed is applied. To treat a dry transom stern effect a special treatment for the free-surface boundary condition is adopted at the free-surface region after the transom stern. Trim and sinkage, which are important in high speed ships, are considered by an iterative method. Pressure and momentum approaches are used to calculate the wave resistance. Numerical calculations are performed for Athena hull and these results are compared with the experimental data and also other computational results.

• 환경영향평가
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• 제25권5호
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• pp.307-318
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• 2016

본 연구는 도시화가 1인당 탄소 배출에 미치는 영향을 도시화와 소득 수준 간의 교호 작용을 중심으로 분석하였다. 이를 위해 84개 국가에 대한 패널 자료를 고정효과 모형을 통해 회귀분석하고 동시에 Pooled LS 모형 및 패널 GLS 모형과도 비교하였다. 그 결과 1인당 탄소배출과 도시화는 비선형적 관계를 이루는 것으로 나타났다. 즉 저소득 국가에서 도시로의 인구 집중이 1인당 탄소 배출을 증가시키는 반면, 고소득 국가에서는 오히려 반대의 효과가 나타났다. 이러한 본 연구의 결과는 도시의 압축성(compactness)과 에너지 소비 패턴에 대한 논의로 확장할 수 있으며, 이를 통해 지속가능한 도시개발을 위한 연구와 정책 개발의 토대를 제공할 수 있다.

• 한국해양공학회지
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• 제35권3호
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• pp.191-202
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• 2021

Studies on very large offshore structures are increasing owing to the development of deep sea, large-scale energy generation using ocean resources, and so on. The enlargement of offshore structures makes the hydroelastic effect and low natural frequency related responses important. Numerical analyses and model tests for hydroelastic and higher-order springing responses of fixed cylindrical structures are conducted in this study. The panel methods with and without the hydroelastic effect with shell elements, and the Morison analysis method with beam elements are applied. To observe the hydroelastic effect for structural strength, two structures are considered: bottom-fixed cylindrical structures with high and low bending stiffnesses, respectively. The surge motions at the top of the structure and bending stresses on the structure are observed under regular and irregular wave conditions. The regular wave conditions are generated considering the ratios of the cylindrical outer diameter to the wave lengths, and keeping the wave steepness constant. The model tests are performed in the three-dimensional ocean engineering basin in the KRISO (Korea Research Institute of Ships and Ocean Engineering). From the numerical and experimental results, in which the hydroelastic responses are only observed in the case of the structure with a low bending stiffness, it is confirmed that the hydroelastic responses are highly dependent on the structural stiffness. Additionally, the higher-order phenomenon on the specified wave condition is analyzed by observing the higher-order springing responses when the incident wave frequency or its multiples with the high wave height coincides with the natural frequency of the structure.

• The Journal of Asian Finance, Economics and Business
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• 제7권4호
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• pp.121-131
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• 2020

This study aims to investigate the interplay between education and local roads on Foreign Direct Investment (FDI) in the Philippines, using economic growth as an instrument. The study used the quantitative research design applying both descriptive and inferential statistics. A combination of Two Stage Least Square Regression Model and three approaches in Panel Regression Model such as Pooled Least Square, Fixed Effect Model, and Random Effect Model were utilized in order to study the effects of education and local roads on foreign direct investment of the Philippines. Based on Fixed Effect regression results, higher education graduates and local road investments, as conditioned by economic growth, were significant factors in order to increase the foreign direct investment in the Philippines. Accordingly, a unit increase in higher education graduates, as conditioned by economic growth, leads to 8.758 unit increases in the foreign direct investment. While, a unit increased in local road investments, as conditioned by economic growth, leads to a 0.002 decrease in foreign direct investment. The regression results of the study suggest that the Foreign Direct Investment in the regions such as CAR, I, II, IV-B, V, VIII, IX, X, XI, XII, XIII, and ARMM are higher compared to Region IV-A.

• 대한조선학회논문집
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• 제47권3호
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• pp.306-320
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• 2010

Modern ultra-large container carriers can be exposed to the unprecedented springing excitation from ocean waves due to their relatively low torsional rigidity. Large deck opening on the deck of container carriers tends to cause warping distortion of hull structure under wave-induced excitation, eventually leading to the higher chance of resonance vibration between its torsional response and incoming waves. To handle this problem, a higher-order B-spline Rankine panel method and Vlasov-beam FE model was directly coupled in the time domain, and the coupled equation was solved by using an implicit iterative method. In order to capture the complicated behavior of thin-walled open section girder, a sophisticated beam-based finite element model was developed, which takes into account warping distortion and shear-on-wall effect. Then, the developed beam model was directly coupled with the time-domain Rankine panel method for hydrodynamic problem by using the fixed-point iteration method. The developed computational scheme was validated through the comparison with the frequency-domain solution on the container carrier model in linear springing regime.

• 노동경제논집
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• 제34권1호
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• pp.71-101
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• 2011

본 연구는 고용보험 DB를 이용하여 구축한 사업체패널 자료(2000~2009년)를 이용하여 고연령층의 고용변화가 청년층 고용에 미치는 효과를 분석한다. 구체적으로 본 연구는 사업체 수준에서 (1) 고령근로자의 비중 증가가 청년층 고용에 미치는 영향과 (2) 고연령층 고용과 청년층 고용 간의 일자리 경합 여부를 실증분석한다. 사업체패널 전체를 이용하여 추정한 결과에서 고연령층의 고용 증가와 노동력 고령화가 청년층 고용 감소를 동반한다는 증거는 발견되지 않는다. 그러나 이와 같은 분석 결과가 하부 표본별 추정에서는 일관되게 관찰되지 않는다.

• Journal of Preventive Medicine and Public Health
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• 제48권6호
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• pp.319-329
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• 2015

Objectives: Parental socioeconomic status (SES) exerts a substantial influence on children's health. The purpose of this study was to examine factors determining children's private health insurance (PHI) enrolment and children's healthcare utilization according to PHI coverage. Methods: Korea Health Panel data from 2011 (n=3085) was used to explore the factors determining PHI enrolment in children younger than 15 years of age. A logit model contained health status and SES variables for both children and parents. A fixed effects model identified factors influencing healthcare utilization in children aged 10 years or younger, using 2008 to 2011 panel data (n=9084). Results: The factors determining children's PHI enrolment included children's age and sex and parents' educational status, employment status, and household income quintile. PHI exerted a significant effect on outpatient cost, inpatient cost, and number of admissions. Number of outpatient visits and total length of stay were not affected by PHI status. The interaction between PHI and age group increased outpatient cost significantly. Conclusions: Children's PHI enrolment was influenced by parents' SES, while healthcare utilization was affected by health and disability status. Therefore, the results of this study suggest disparities in healthcare utilization according to PHI enrollment.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.43-54
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• 2021

Human capital and innovation capacities are essential elements and one of the sustainable approaches to driving economic growth. However, there is debate among scholars concerning these two factors in fostering economic growth. This study investigates the relationships between human capital and innovation capacity and economic growth in selected ASEAN countries, namely, Malaysia, Thailand, and Indonesia. Economists widely discussed the interrelation of human capital and innovation. A large body of literature stated that human capital is an essential factor and engine of economic growth. Innovation has become key in transforming the economic development of developing countries. We analyze human capital (HC) and innovation capacity (INC) using static panel data analysis. The data analysis shows that the fixed-effect model is the best model in this study. Further, human capital (HC) has a significant positive relationship with economic growth. Meanwhile, innovation capacity has no significant relationship with economic growth. We also found that Malaysia's coefficient of human capital and innovation capacity is higher and more efficient than in Thailand and Indonesia. In conclusion, human capital and innovation capacity are crucial elements for measuring economic growth. Skilled human capital contributes significantly to the economic growth and economic development of a nation.

• 정보관리학회지
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• 제38권4호
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• pp.1-23
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• 2021

본 연구에서는 베스트셀러 목록에 포함된 도서의 순위가 공공도서관에서의 평균 대출 건수에 미치는 영향을 패널분석을 통해 살펴보고자 하였다. 본 연구를 위해 문화 빅데이터 플랫폼을 통하여 국립중앙도서관이 제공하는 데이터를 바탕으로 2018년 1월 1일부터 2019년 12월 29일까지 총 104주 동안의 분석 대상 도서 179권의 공공도서관 대출 데이터 세트를 생성하였고, YES24 웹사이트를 통해 같은 기간 주간 베스트셀러 목록 데이터 세트를 구축하였다. 공공도서관 대출과 베스트셀러 도서 순위 간 정확한 관계를 확인하기 위해 패널자료의 특성을 활용한 분석 방식인 선형회귀모형, 고정효과모형, 확률효과모형 등 세 개의 모형을 비교한 결과, 고정효과모형이 가장 적합한 것으로 나타났다. 순위 데이터 결측값이 47주 미만인 179권의 도서의 자료를 고정효과모형으로 분석한 결과, 도서의 베스트셀러 순위가 한 단계 내려가면 공공도서관에서의 해당 도서 평균 대출 건수가 0.108권 유의미한 수준에서 감소한다는 것을 밝혀내었다. 또한, 베스트셀러 순위가 도서 평균 대출 건수에 미치는 효과가 도서의 내용분류에 따라 상이함을 알 수 있었다. 이 연구는 베스트셀러 순위가 사람들의 도서관 대출행태에 영향을 미치고 있음을 실증적으로 확인한 것으로, 공공도서관에서는 이용자의 요구를 예측하고, 장서 개발 정책 수립에 베스트셀러 목록을 비롯한 사회문화적 맥락을 고려할 필요가 있음을 시사한다.

• Journal of the Korean Data and Information Science Society
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• 제28권1호
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• pp.1-10
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• 2017

경시적 자료를 이용한 아동 학업성취도에 영향을 주는 요인을 찾기 위한 기존의 분석들은 각 아동의 반복 측정된 자료들이 독립이라고 가정한 모형을 주로 이용하였다. 본 연구에서는 기존 연구들에서 고려한 아동 학업성취도에 영향을 주는 변수들을 선택하여 반복 측정된 경시적 자료의 종속성을 고려한 고정효과와 임의효과를 포함하는 선형혼합모형으로 분석하여 아동 학업성취도에 영향을 주는 변수들은 무엇인지, 각 아동의 특성들이 반영되는 임의절편과 임의기울기가 있는지를 파악하는 것이 연구의 목적이다. 본 연구에 사용된 자료는 한국복지패널 1, 4, 7차 부가조사 중에서 아동용 설문문항에 대한 자료이고, 국어, 영어와 수학의 학업성취도 점수의 합을 아동 학업성취도로 한다. 선형혼합모형을 이용한 분석 시에 다중공선성의 검토와 결측치의 특성을 파악하고 적절한 오차의 상관행렬을 선택한다.