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왜 다시 EBS인가?- EBS강의가 사교육비와 학업성취도에 미치는 영향
한상억 한국교육재정경제학회 2023 敎育財政 經濟硏究 Vol.32 No.3
Due to the outbreak of COVID-19, concerns about learning loss and the soaring expenses of private education have become prominent social issues. In light of these concerns, the government is actively exploring strategies to enhance the integration of EBS lectures into the College Scholastic Ability Test(CSAT). While previous studies have primarily focused on the initial impact of the 2010 college entrance exam policy, there remains a lack of research on the dynamic effects of the policy over time. Firstly, in order to estimate the effect of EBS lectures on the reduction in private education expenses, we employ the Correlated Random Effects approach - Panel Tobit Model along with other panel data models, using data from high school students in the Seoul Education Longitudinal Study (SELS). Additionally, we evaluate the outcome of EBS lectures compared to other educational goods such as school achievement. The results indicate that, except for the early stages of policy implementation, EBS lectures have significantly reduced private education expenses and positively influenced academic achievement in math and English courses. However, a continuous decline in EBS lecture participation rates and the preference of top-performing students for private education seem to diminish the overall impact of the policy. Accordingly, policy responses addressing these issues should be considered to maximize the effectiveness of the EBS lecture policy.
소나무 , 해송 및 리기다소나무에 있어서 건전엽과 (健全葉) 솔잎혹파리 피해엽의 생화학적 물질비교
한상억,이돈구,전상근 ( Sang Urk Han,Don Koo Lee,Sang Keun Chon ) 한국산림과학회 1980 한국산림과학회지 Vol.50 No.1
Monoterpenes, phenolic substances, growth substances and total nitrogen from normal needles and infested needles attacked by Thecodiplosis japonensis were compared for Pinus densiflora, Pinus thunbergii and Pinus rigida. The results obtained in this study were as follows: 1. Major monoterpene components in P. densiflora needles were β-phellandrene, α-pinene and those in P. rigida needles were β-pinene and α-pinene. In P. rigida resistant to this insect, infested needles showed higher α-pinene, β-pinene and myrcene but lower camphene, limonene and β-phellandrene than normal needles. 2. Orcinol, catechol ferulic acid, salicylic acid and five unknowns were detected in P. rigida needles whereas orcinol, catechol, ferulic acid and four unknowns in P. densiflora needles. 3. Tryptophan, a precursor of IAA, was detected in larvae and also in gall tissues of both P. densiflora and P. thunbergii needles. This fact shows that growth substances may involve in gall formation by Thecodiplosis japonensis. 4. Total nitrogen contents per unit needle weight were neither significantly different between P. densiflora and P. rigida, nor between normal and infested needles.
잣나무 생장특성의 광의의 (廣義) 유전력과 수형목 (秀型木) 클론선발에 의한 개량효과
한상억,최선기,권혁민,이상붕 ( Sang Urk Han,Sun Ki Choi,Hyuk Min Kwon,Sang Boong Lee ) 한국산림과학회 1985 한국산림과학회지 Vol.69 No.1
Growth characters such as height, DBH, crown width, branch length and branch diameter were measured from 23 clones of plus trees of Pinus koraiensis. The results were as follows; 1) Differences between the largest and smallest clones were amounted to 41% in height, 81% in DBH, 50% in crown width, 55% in branch length and 83% in branch diameter. 2) There were significant differences between clones in every growth characters and correlation coefficients between growth characters were positive and significant (r = 0.418^*-0.917^(**)). 3) The broad sense heritabilities were 0.46 for height, 0.45 for DBH, 0.28 for crown width, 0.26 for branch length and 0.18 for branch diameter. 4) The genetic gains predicted for each characters were ranged from 4.1% to 11.1%, when selecting the best 3 out of 23 clones.