실선에 의한 표류 예측모델에 관한 연구

이창헌,김광일,유상록,김민선,한승훈 한국수산해양기술학회 2024 수산해양기술연구 Vol.60 No.1

표류 예측모델을 제시하기 위하여 표류시험을 수행하였으며, 이상치 및 영향점을 검증한 후 회귀분석을 하였다. DFFITS, Cook’s distance 분석결과, 표류속도의 경우 데이터 index 1, 27, 28, 72, 73, 74번째, 표류방향의 경우 index 2, 8, 68, 70, 71, 73, 74번째에서 회귀모형에 영향을 미치는 것으로 나타났다. 하지만, 회귀계수에 영향을 미치는 척도를 나타내는 DFBETAS 분석 결과, 표류속도에서는 index 1번째에서만 풍향의 DFBETAS 절대값이 임계값인 1을 초과하지만, 1에 가까우며 예측값에 대한 적합도에는 크게 영향이 미치지 않을 것으로 판단되어, 81개 샘플에 대해 다중회귀분석을 하는 데 크게 문제되지 않을 것으로 분석되었다. 예측 표류속도 및 표류방향의 예측값과 잔차의 분석 결과, 선형성과 독립성을 만족하였다. 독립변수의 다중 공선성은 10이하로 나타나 공선성이 전혀 없었으며, 잔차의 왜도 및 첨도에서도 임계값 이하로 나타났으며, omnibus 및 kolmogorv-smirnov 검정통계량도 만족하는 것으로 나타나 정규분포를 따른다고 할 수 있다. 다만, 잔차의 독립성을 나타내는 Durbin-Watson 검정통계량에서는 미흡한 점이 있지만, 양의 상관관계를 이루고 1에 가까우므로 큰 문제가 없다고 볼 수 있었다. 종속변수와 독립변수들 상관계수는 표류속도에서 유속이 0.49, 표류방향에서 유향이 0.81로 가장 높게 나타났다. 독립변수가 종속변수에 미치는 비율을 나타내는 표준회귀계수에서 표류속도는 유속이 47.1%, 표류방향에는 유향이 58.1%로 영향력이 가장 큰 변수로 나타났고, 도출한 다중회귀예측모델의   는 표류속도 69.3%, 표류방향 79.3%이며,    는 67.6%, 78.3%인 것으로 나타났다. 향후, 연구결과로 나타난 독립변수에 의한 표류속도/표류방향의 다중선형회귀모델을 추가적인 실험을 통하여 확인이 필요하다. 또한, 다양한 회귀모형을 적용하여 예측 정확도가 높은 모형 도출이 필요하다. In order to present a predictive drift model, Jeju National University's training ship was tested for about 11 hours and 40 minutes, and 81 samples that selected one of the entire samples at ten-minute intervals were subjected to regression analysis after verifying outliers and influence points. In the outlier and influence point analysis, although there is a part where the wind direction exceeds 1 in the DFBETAS (difference in Betas) value, the CV (cumulative variable) value is 6%, close to 1. Therefore, it was judged that there would be no problem in conducting multiple regression analyses on samples. The standard regression coefficient showed how much current and wind affect the dependent variable. It showed that current speed and direction were the most important variables for drift speed and direction, with values of 47.1% and 58.1%, respectively. The analysis showed that the statistical values indicated the fit of the model at the significance level of 0.05 for multiple regression analysis. The multiple correlation coefficients indicating the degree of influence on the dependent variable were 83.2% and 89.0%, respectively. The determination of coefficients were 69.3% and 79.3%, and the adjusted determination of coefficients were 67.6% and 78.3%, respectively. In this study, a more quantitative prediction model will be presented because it is performed after identifying outliers and influence points of sample data before multiple regression analysis. Therefore, many studies will be active in the future by combining them.

김대중 정부 시기 남북대화의 전개와 평가

이창헌 평화문제연구소 2004 統一問題硏究 Vol.16 No.2

In February 1998, the Kim Dae-Jung government started in South Korea. Since then, the Kim Dae-Jung government established the Reconciliation and cooperation policy for the South-North Korean dialogue, in which the government not only attempted to help North Korea to stabilize North Korean security but also aided North Korea to change into a rational national recognized by the international society for solving the national problem of division. As a result, South-North Korean summit talks have been held for the first time since the division of the peninsula, separated families have been reunited six times and South Korea and North Korea expanded bilateral economic, social and cultural exchanges and cooperation. But, there have been criticisms that South Koreas Reconciliation and cooperation policy towards North Korea and the dialogue did not contribute a lot to solve the cold war divisions of the Korean peninsula. This paper attempts to review and evaluate the South-North Korean dialogue held during the Kim Dae-Jung government. Thus, this study provides future directions by examining policy environment and analysing progress in the South-North Korean dialogue as well as the outcome and problems of the policy dialogue.

방사성 폐기물 내 55Fe, 90Sr 및 94Nb의 분리 연구

이창헌,정기철,임석남,김원호,지광용 한국방사성폐기물학회 2003 한국방사성폐기물학회 학술논문요약집 Vol.2003 No.11

때죽나무 종자의 발아촉진 및 종자내 성분의 변화

이창헌,서병수,박지원 ( Chang Heon Lee,Byung Soo Seo,Ji Won Park ) 한국산림과학회 1998 한국산림과학회지 Vol.87 No.4

This research was carried out to promote the seed germination of Styrax japonica, by several pretreatments and to examine its seedling growth and seed component variations according to time and pretreatment. The results are as follows ; 1. Styrax japonica seeds are usually germinated after more than one year cold stratification. However, when the seeds were stratificated for 5 months after dipped in the solution of 70% H₂SO₄ for 30 minutes and also treated with GA₃(3000ppm), they showed 55% germination. This demonstrated that the seeds could be germinated in one year when pretreated. 2. The growth of one-year-old seedlings after pretreatment was the same as that of two-year-old seedlings when compared 160 days after seeding. 3. Before seeding, one-year-old, pretreated seeds of Styrax japonica showed increased moisture content but decreased crude fat, carbohydrate and exude ash, which were similar to the components of two-year-old seeds.

폐기물 소각로의 최근의 진보

이창헌,Lee, Chang Heon 환경보전협회 1985 환경정보 Vol.7 No.7

방사성 폐기물 내 59/63Ni의 선택적 분리

이창헌,정기철,최광순,지광용,김원호 한국방사성폐기물학회 2005 한국방사성폐기물학회 학술논문요약집 Vol.3 No.1

최근 남북대우의 환경요인분석

이창헌 朝鮮大學校 統一問題硏究所 1992 統一 問題 硏究 Vol.10 No.-

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돈분 처리에 의한 빈도리나무 유묘생육 및 무기양분 흡수에 관한 연구

이창헌,강학모,진재준,홍지숙,김미자 한국환경복원기술학회 2018 한국환경복원기술학회지 Vol.21 No.3

This study was conducted to obtain a reliable result assessing proper amount of solid swine manure for the growth of Deutzia crenata seedlings. Seedling growth dry weight, chlorophyll content inorganic nutrients and soil chemical properties were investigated. 1. When treated with solid swine manure, seed germination rate was highest on the control. However, germination rates tended to decrease when treated with swine manure at high concentrations. 2. The growth of seedlings treated with swine manure was always higher than that of in control. At the 1.0% of swine manure treatment, the growth rate of the seedlings was highest. 3. Seedling dry weight was highest at the 1.0% swine manure treatment. The amount of inorganic nutrients absorbed by the seedling was generally high with the 1.0% treatment, declined sharply with the 2.0% treatment. 4. For the planting soil of Deutzia crenata, the higher the concentration of swine manure, the lower the soil pH. However, nitrogen, available P, K, Na, Mg and Ca contents in the soil have increased with higher concentrations.

계분 처리에 의한 빈도리나무(Deutzia crenata) 종자발아·유묘생육 및 무기물 흡수에 관한 연구

이창헌,김미자,진재준,강학모 한국환경복원기술학회 2018 한국환경복원기술학회지 Vol.21 No.6

This study was conducted to obtain proper amount of solid poultry manure in the beginning phase of Deutzia crenata growth. Seedling growth increment, dry weight, inorganic matter uptake and chem- ical changes of soil according to the concentration of solid poultry manure fertilization. 1. When treated with solid poultry manure, seed germination rate was highest on the control. However, germination rates tended to decrease when treated with at high concentrations. 2. The growth of seedlings treated with poultry manure was always higher than that in control. At the 1.0% of poultry manure treatment, the growth rate and dry weight of the seedlings was highest. 3. The amount of inorganic nutrients absorbed by the seedling was generally high with the 1.0% treatment, declined sharply with the 2.0% treatment. 4. For the planting soil of Deutzia crenata, the higher the concentration of poultry manure, the lower the soil pH. However, nitrogen, available P, K, Na and Mg contents in the soil have increased with higher concentrations.

4자회담의 전개과정 및 추진방향

이창헌 한국동북아학회 1997 한국동북아논총 Vol.2 No.3