XGBoost 기반의 2단계 확률적 일사량 예측과 태양광 예측 알고리즘의 성능 검증

이유림(Yurim Lee),김현진(Hyunjin Kim),이다한(Dahan Lee),이채정(Chaijung Lee),이두희(Duehee Lee) 대한전기학회 2019 전기학회논문지 Vol.68 No.12

We propose the novel solar power forecasting algorithm by using the Extreme Gradient Boosting (XGBoost) machine based on the 2-stage forecasting structure. Our algorithm is implemented to solve three problems. First, the solar power is linearly proportional to the solar irradiation on a target solar panel, but it is hard to obtain the target solar irradiation. Therefore, in the first stage, we predict the target solar irradiation by using the XGBoost based on numerical weather prediction, which is measured on a different location but modified for the target location. Second, the forecasting errors on the predicted solar irradiation can be transferred to the second stage when the predicted solar irradiation is used to predict the solar power. We forecast the conditional error distribution of predicted irradiation by collecting forecasting errors, and we sample solar irradiation scenarios, which are converted to the solar power scenarios. Then, the final point forecast of solar power is estimated by calculating the median of scenarios so that we can improve the forecasting accuracy. Third, in this process, the quality of numerical weather prediction deteriorates as the target hour is farther. Therefore, we build forecasting models for each target hour in parallel to minimize the forecasting accuracy deterioration from the quality deterioration. Finally, we verify our proposed algorithm by participating in the solar power forecasting competition hosted by KPX.

스웨덴, 일본, 한국의 일가족양립지원정책 비교

이채정 ( Chae Jeong Lee ) 연세대학교 사회발전연구소 2009 현대사회와 문화 Vol.28 No.-

이 논문은 스웨덴, 일본, 한국의 일가족양립지원정책을 비교하여, 일본과 한국에서의 스웨덴식 정책 시행에 걸림돌이 되는 요인을 찾는다. 한국이 아동수당을 도입하지 않았다는 점만을 제외하고는 스웨덴, 일본, 한국의 일가족양립지원정책의 큰 틀은 유사하다. 그러나 보육정책 집행의 이원화가 스웨덴과 일본, 한국의 정책 내용적 측면의 차이점이다. 또한, 부모는 사설보육시설과 사교육에 의지하는 경향이 있으며, 고용주는 직장 내 보육시설의 설치를 최소화하여 실시하고, 남성 노동자의 육아휴직 이용도 매우 저조하다. 일본과 한국 아버지들의 저조한 육아휴직 이용과 부모들의 사설보육시설과 사교육 선호는 이 두 국가의 노동시장 구조와 관련되어 있다. 일본과 한국의 노동자들은 OECD 국가 중 가장 긴 시간을 노동에 사용하고 있으며, 이는 아버지들의 자녀돌봄을 방해하는 요인 중 하나이다. 교육을 통한 노동시장 진입에 있어서의 치열한 경쟁과 노동시장 진입 시의 첫 위치에 따른 노동시장 지위의 분리현상(labour market segregation)은 일본과 한국의 부모가 자녀의 경쟁력을 키우기 위해 사교육을 선호하는 이유이다. 따라서 스웨덴식 정책적 성과를 일본과 한국에서 달성하기 위해서는 일가족양립지원정책과 노동정책의 통합적인 시행을 추진해야 한다. This study compares work-family reconciliation policies in Sweden (the prototype of the study), Japan and Korea, and identifies barriers that interrupt the implementation of a Swedish work-family reconciliation approach in Japan and Korea. The outlines of work-family reconciliation policies in Japan and Korea are similar to the Swedish, excepting the absence of a Korean childcare allowance system. However, less coordination and dual policy approach are major policy limitations in Japan and Korea. As a result, individuals adopt a strategy of relying on private care and education, while it is still common for both employers and employees to make minimal use of state-sanctioned policies such as workplace nurseries or paternity leave. Fathers` low utilisation of parental leave and parents` preference for private childcare and education, in both Japan and Korea are linked to these countries` labour-market structures. Japanese and Korean workers have the longest working hours among OECD countries, which interrupts fathers` involvement in childcare. The competitiveness to enter the labour market through education and labour market segmentation based on the first job status are the reasons why Japanese and Korean parents prefer private childcare and education. Thus, in order achieve Swedish-style work-family reconciliation, Japan and Korea need to implement integrated work-family reconciliation and labour policies.

무상보육정책이 영유아 자녀 양육비용 지출에 미친 영향 분석

이채정(Lee, Chae Jeong),권혁주(Kwon, Huck Ju) 서울행정학회 2017 한국사회와 행정연구 Vol.28 No.3

본 연구는 한국복지패널 7차년도(2011년)와 11차년도(2015년) 자료를 활용하여 무상보육 실시 이전과 이후 영유아 양육가구의 자녀양육비 지출이 어떻게 변화하였으며, 그러한 변화를 유발한 요인이 무엇인가를 분석하였다. 분석 결과, 저소득가구(1분위)는 무상보육 이전과 이후 모두 자녀양육비 지출 수준이 다른 소득계층에 비하여 높았고, 고소득가구(5분위)는 무상보육 이후 시설외보육비용을 중심으로 자녀양육비 지출이 증가하였다. 또한, 무상보육 실시 이후 가구의 소득수준이 높을수록 통계적으로 유의미하게 엔젤지수가 증가한 것으로 분석되었다. 이는 현행 보육정책이 부모의 노동시간과 시설보육서비스 제공시간의 불일치에 따른 돌봄공백을 축소하지 못하여 저소득가구의 자녀양육부담을 경감하지 못하였으며, 무상보육정책이 고소득가구의 시설보육외비용 지출 증가를 촉발하여 소득계층에 따른 자녀양육방식의 차이를 발생시킬 수 있음을 의미한다. 요컨대, 무상보육은 당초 목표대로 영유아 양육가구의 자녀양육부담을 경감했다기보다는 가구별 소득수준에 따른 정책효과의 차이로 인하여 소득계층 간 자녀양육의 질적 차이를 야기하고 있다고 볼 수 있다. 향후 보다 면밀한 분석을 토대로, 소득계층과 맞벌이여부, 부모의 근무형태 등을 반영하여 보육료를 지원하는 방식으로 보육정책을 개편하는 방안 등을 검토해 볼 필요가 있다. This study analyzes the change in family’s child support expenses with a child under the age of five by comparing the before and after of the expansion of childcare subsidy and figure out reasons of the change of child support expenses in households. To accommodate the study, data collected from the 2011’s 7th and 2015’s 11th wave of Korean Welfare Panel Study were utilized. As a result, the child support expenses of the lower income family(the bottom 20 percent) were higher than other income group before and after the childcare subsidy expansion in 2013. In the case of the higher income family(the top 20 percent), the child support expenses, especially the cost for private childcare not using the day-care centers and kindergartens, which can use the governmental childcare subsidy, was increased after the childcare subsidy expansion. In addition, after the expansion of the childcare subsidy, the angel coefficient of household was inclined statistically significant as the income level of family is increased. It implies that the childcare policy based on the expansion of childcare subsidy cannot lessen the individual households’ burden of child caring of lower income family since the care deficit did not mitigate due to the discord of parents’ working hours and childcare service hours provided by day-care centers and kindergartens. Moreover, the expansion of childcare subsidy triggers the private childcare expenses of higher income family and it might bring the difference of child rearing according to the income level of households. To sum up, the expansion of childcare subsidy might not accomplish the policy goal which was lessening the child caring burden of families with children under aged five. It tends to incur the difference of quality in child rearing among income level because of the different policy impact in association with different income level of families.

무상보육정책의 영유아 연령별 자녀양육비용 경감 효과 분석

이채정 ( Chae Jeong Lee ) 한국정책학회 2018 韓國政策學會報 Vol.27 No.2

본 연구는 한국복지패널을 활용하여 무상보육정책 실시로 인하여 자녀양육비용 지출이 경감되었는지를 영아와 유아 양육가구별로 이중차이모형을 적용하여 분석하였다. 분석 결과, 영아 양육가구는 자녀양육비용이 경감된 반면에 유아 양육가구는 증가한 것으로 나타났다. 구체적으로, 영아 양육가구는 월평균 약 23.6만원 감소(시설보육비용 약 23.3만원, 시설보육외비용 약 0.3만원 감소)하였으며, 유아 양육가구는 월평균 약 7.4만원 증가(시설보육비용 약 3.0만원, 시설보육외비용 약 4.4만원)하였다. 이는 무상보육정책이 시설보육을 이용하는 영아 양육가구의 자녀양육비용은 경감하지만, 학령기 진입을 앞둔 유아양육가구는 정부의 보육료·유아학비 지원으로 발생한 여분의 경제적 자원을 부가적인 특별활동이나, 베이비시터, 학습지 등 시설보육 이외의 보육서비스 이용에 지출하고 있다는 것을 보여준다. 2016년 기준 영아 어린이집 이용률이 36.0%로 일부 영아 양육가구만이 자녀양육비용 경감 효과를 누리고 있고, 유아 양육가구는 가구별 경제적 자원의 차이에 따라 보육서비스의 질적 차이가 유발될 수 있다는 점에서 정책수행방식의 적절성 등에 대한 논의가 필요하다. 한편, 본 연구의 분석결과는 표본 수의 한계로 인하여 일반화가 제한적이므로, 후속연구에서는 좀 더 누적된 자료를 활용하여 무상보육정책의 영유아 연령별 자녀양육비용 경감 효과를 분석해 볼 필요가 있다. This study analyzes the effect on the childcare cost reduction after implementing a free childcare policy - under which all households with children under five would receive childcare subsidy - using the Korea Welfare Panel by applying the difference-in-differences model for households with infants and toddlers. As a result, infant care households were shown to have reduced their child support costs while child support costs of toddler care households had increased. More specifically, child support costs of infant care households decreased by 236 thousand won per month on average, while those of toddler care households increased by 74 thousand won per month on average. It shows that the free childcare policy reduces childcare costs of the households that use facility care, but the households with toddlers who are about to enter the school are more likely to spend additionally for babysitter, childminder or home study materials. The adequacy of policy implementation methods needs to be discussed since only some infant care households enjoy the benefit of cost reduction in childcare as the utilization rate of infant daycare centers was 36.0% in 2016. In case of toddler care households, the differences in economic resources can trigger the difference in the quality of childcare services. Due to the limited number of samples, the analysis results of this study are limited in general. In the follow-up studies, it is recommended that more accumulated data be used to analyze the effectiveness of reducing childcare costs for children’s age groups.

Digital Library를 위한 텍스타일 프린트 디자인의 이미지 유사성 평가

이채정 ( Chae Jung Lee ),김주용 ( Joo Yong Kim ) 한국감성과학회 2007 감성과학 Vol.10 No.4

OECD 회원국의 사회지출 효율성 비교

이채정(Chae-jeong LEE),탁현우(Hyunwoo Tak) 호남대학교 인문사회과학연구소 2023 인문사회과학연구 Vol.66 No.2

Fullerene과 Polyaniline을 이용한 유기 Peltier소자의 개발

이채정(Lee, Chae-Jung),김주용(Kim, Joo-Yong) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.06

Temperature difference between two plates occurs when a current is passed though two semi-conductors that are connected each other at two junctions. The current drives a transfer of heat from one junction to the other. In this study, the thermoelectric module based on th Peltier effect was made by combing fullerene and polyaniline. Continuous temperature measurements on both surfaces were performed at room temperature(25.4?C) by an infrared non-contact thermometer. The results showed that cool ing effect of 2.2?C was attained by 30 seconds, after which the effect was continuously vanished mainly due to electro decomposition.

보육정책 확대의 효과성 분석

이채정(Chae Jeong Lee),탁현우(Hyunwoo Tak) 한국정책분석평가학회 2017 政策分析評價學會報 Vol.27 No.3

This study analyses the impacts of childcare policy expansion on the childcare service use and child support expenses of families with children under the age of five during the period (2005-2012) of steady expansion of policy beneficiaries and during the period (2010-2015) of childcare service provision for all income levels. As a result, the childcare subsidy reduced child support expenses of families, but it did not increase the use of the childcare service. During the steady expansion period, the beneficiaries of the childcare subsidy were more likely to use nursery facilities. However, childcare service for all income levels did not have statistically significant impact on the use of childcare centres. Moreover, child support expenses of higher income families did not decrease regardless of the childcare subsidy given. Child support expenses tend to increase if a child’s mother is a high-income earner with good education. During the free childcare service provision period, the expenses for private childcare increased for homeowner households, in case of household with its own house. To improve the effectiveness of childcare policy, it is crucial that the subsidy differential between childcare subsidy and home care allowance requires to be mitigated. Also, policy implementation needs to be reconsidered to reflect various factors including parents’ income level and working hours.

기술혁신에 따른 직무대체의 사회적 영향 탐색 : 사회적 비용 추계와 사회적 인식 검토를 중심으로

이채정(LEE, Chae-jeong),조희찬(CHO, Hee-chan),장윤정(CHANG, Yoon jeong) 강원대학교 사회과학연구원 2021 사회과학연구 Vol.60 No.1

4차 산업혁명에 따른 지능정보사회의 도래는 노동과 고용관계를 다각도에서 변화시킬 것이라는 예측이 지배적이다. 전통적으로 인간에 의해 행해지던 생산활동을 네트워크, 인공지능, 로봇 등 혁신적 기술이 빠르게 대체하게 되어, 기술혁신의 영향에 취약한 분야에 종사하던 인간은 실직하거나, 급여가 감소하여 소득수준이 낮아지는 등의 변화에 처하게 된다는 것이다. 본 논문은 이러한 관점에서 진행된 기존의 기술혁신에 따른 직무대체율 연구에 기반하여, 직무대체가 일어날 경우 소득수준 하락으로 인해 한국 사회에 필요하게 될 공공부조 증가분과 조세수입 및 사회보험료 감소분를 추계하고, 직무대체로 인한 소득 감소와 사회적 인식의 관계를 탐색하였다. 2018년 기준의 직종별 직무대체율을 한국노동패널 원자료의 소득정보에 적용하여 추계한 결과, 빈곤비용은 42∼54% 증가하며, 소득세수는 45∼57% 감소하고, 사회보험료수입은 10∼16% 감소하는 것으로 나타났다. 한편, 자산 및 소득 수준이 낮고, 가구의 경제상태를 부정적으로 인식하는 경우 직무대체로 인한 가처분소득 감소폭도 클 것으로 분석되었다. 뿐만 아니라, 직무대체로 인한 가처분소득 감소폭이 큰 가구 중에서도 자산수준이 낮은 가구에서는 5년 뒤 삶의 질에 대한 주관적 전망이 낮아지지만, 자산수준이 높은 경우에는 삶의 질에 대한 전망에 유의한 영향이 없는 것으로 나타났다. 이러한 분석 결과는 직무대체에 의한 국가의 사회지출 투입 재원 감소가 현행 사회보장체계 유지에 부정적인 영향을 미치며, 실직과 급여 감소 등에 의해 양극화 문제가 심화할 수 있음을 시사한다. The advent of the intelligent information society, as a result of the fourth industrial revolution, is often perceived as a threat that will redefine a wide range of jobs. Technologies such as artificial intelligence and robots penetrate the domain of tasks that were regarded as highly sophisticated for machines to emulate and may lead to extensive technological unemployment. This study estimates the amount of increase needed in public assistance in Korean society due to the anticipated decrease in tax revenue and social insurance premiums from automation. Using the data from the Korean Labor and Income Panel Study and the predicted level of unemployment from former studies, we show that the poverty cost is expected to increase by 42-54%. Moreover, income tax revenue is estimated to decrease by 45-57%, while social insurance premiums decrease by 10-16%. Households with low income or assets were more vulnerable to the reduction in disposable income due to job displacement. This study also shows that the subjective outlook for the quality of life of wealthy households was not as significantly affected by the decreased disposable income due to automation as that of households with fewer assets. These results suggest that the job replacement by technological innovation may undermine the upkeep of the current social security system and worsen income inequality.

프랑스와 한국의 공공의료서비스 전달체계 비교분석

이유현(Youhyun Lee),이채정(Chae-jeong Lee) 한국비교정부학회 2021 한국비교정부학보 Vol.25 No.3

(Purpose) This study aims to present the direction of future public healthcare service delivery systems through in-depth comparative analysis in France and Korea. Through this paper, we aims to understand how government and market relationships are established to provide social services in the two countries. We also expect to be able to identify its differential characteristics. (Design/methodology/approach) A two-step qualitative approach is conducted. First, the research examines the commonalities and differences of the public healthcare service delivery system in France and Korea, which are considered as social insurance-based welfare states. Second, the study evaluates the role of the state-to-market among countries with similar social welfare systems. For the comparison, Germany and Japan, social insurance-based welfare states, are chosen as the comparative groups. (Findings) The characteristics of the public healthcare service delivery system in France and Korea are analyzed. Additionally, the level of government intervention in the public healthcare service delivery systems is measured. According to the analysis, France has a low rate of self-charge, and the proportion of healthcare, public hospitals, and public beds among public funds was high. Therefore, France is more of a complete government intervention model. Subsequently, in Korea, the percentage of self-payment was high, and the percentage of healthcare, public hospitals, and public beds was low among public funds. Thus, Korea is close to a complete market intervention model and has the opposite public healthcare service delivery system compared to France. (Research implications or Originality) This study presents some rationales for expanding public hospitals and beds in align with the reinforcement of the publicness of health service. The two-stage qualitative analysis methodology identified the characteristics of the public healthcare service delivery systems of both countries.