• 한국환경과학회지
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• 제26권10호
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• pp.1111-1124
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• 2017

This study aimed to understand the distribution of vegetation in the eastern and western sides of the Baekdudaegan (ridge) dividing the Odaesan National Park, as influenced by its topography and climate. The actual vegetation, topography and climate for each side were used in the overlay analysis. The results of the analysis of actual vegetation showed a high distribution rate of Quercus mongolica forest on both the eastern and western sides. On the eastern side, the distribution rate of Pinus densiflora forest and P. densiflora-Q. variabilis forest was high, while the western side had a high distribution rate of deciduous broad-leaved tree forest and Abies hollophylla forest. A clear trend was identified for vegetation distribution with respect to elevation but not with respect to slope or aspect. The results of micro-landform analysis showed that the P. densiflora forests in the ridge and slope and the deciduous broad-leaved tree forest in the valley were respectively distributed with a high ratio. In terms of climate, the eastern side revealed an oceanic climate, with a relatively high average annual temperature, while the western side was characterized by relatively high average annual humidity and average annual precipitation. The distribution rate of P. densiflora forest was found to be high on the eastern side of the mountain range.

• The Korean Journal of Ecology
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• 제16권3호
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• pp.305-316
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• 1993

Stands profiles, yearly changes in growth of annual rings, age and diameter structure, and spatial distribution pattern of individuals in the Pinus densiflora stands around the Yeocheon industrial complex were investigated. Growth of annual ring in Pinus densiflora, which survived when vegetation of this area was damaged by air pollutants, was suppressed for about 10 years since 1974 when factories in this area began to operate, but since then such suppressed growth tended to be recovered. It was supposed that the suppresed growth was originated from air pollution and that improvement of growth since the suppressed period was due to the release from competition with them by death of neighbouring trees and the resuction of the amount of air pollutants. Physiognomy of Pinus densiflora stands showed mosaic pattern composed of different patches. Spatial distribution pattern of individuals an stand profiles were similar to those of Pinus densiflora stands regenerated after natural and artificial disturbances. In an age distribution diagram, age of Pinus densiflora population ranged from 1 to 33 years, Among these individuals were recrited corresponded to the suppresed period of growth of annual ring in Pinus densiflora survived when the vegetation was damaged by air pollution. On the other hand, from the result of analysis of frequency distribution diagram of diameter, it was postulated that even if whis Pinus densiflora community can be maintained as it is for the time being, it might be changed to Quercus community with the lapse of time.

• Advances in Energy Research
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• 제6권1호
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• pp.35-54
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• 2019

A successful blade design must satisfy some criterions which might be in conflict with maximizing annual energy yield for a specified wind speed distribution. These criterions include maximizing power output, more resistance to fatigue loads, reduction of tip deflection, avoid resonance and minimize weight and cost. These criterions can be satisfied by modifying the geometrical parameters of the blade. This study is dedicated to the aerodynamic assessment of a 20 kW horizontal axis wind turbine operating with two possible airfoils; that is $G{\ddot{o}}ttingen$ 413 and NACA 2415 airfoils (the Gottingen airfoil never been used in wind turbines). For this study parameters such as chord (constant, tapered and elliptic), twist angle (constant and linear) are varied and applied to the two airfoils independently in order to determine the most adequate blade configuration that produce the highest annual energy output. A home built numerical code based on the Blade Element Momentum (BEM) method with both Prandtl tip loss correction and Glauert correction, X-Foil and Weibull distribution is developed in Matlab and validated against available numerical and experimental data. The results of the assessment showed that the NACA 2415 airfoil section with elliptic chord and constant twist angle distributions produced the highest annual energy production.

• 식품기술
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• 제25권3호
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• pp.297-305
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• 2012

• The Korean Journal of Ecology
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• 제17권3호
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• pp.261-275
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• 1994

수도권과 그 주변의 33장소의 리기다소나무 숲에서 연륜생장과 잔뿌리의 수직분포를 조사하였다. 생리적 연령이 16년과 20년 사이의 연륜의 생장은 전원지보다 도심지에서 불량하였다. 그리고 최근 5년간 (1985~1989)의 연륜생장은 연령 11년~20년, 연령 21년~30년 및 연령 31년~40년 그룹 모두에서 도심지에서 거리가 멀어짐에 따라 양호하였다. 리기다소나무 잔뿌리의 양은 도심지, 주변지 및 전원지 모두에서 토양의 깊이가 깊어짐에 따라 지수함수적으로 감소하였고, 그 양은 전원지에 비해 도심지에서 매우 적었다. 그리고 전원지의 잔뿌리의 수직분포와 비교해 볼 때, 도심지에서 잔뿌리는 토양층보다 낙엽층에 많이 분포하였다. 그리고 낙엽층 속의 잔뿌리 양과는 유의한 음의 상관이 있었다. 이들 결과로부터 도심지에서 리기다소나무 생장감소는 잔뿌리 생장감소와 잔뿌리의 비정상적인 수직분포에 원인이 있는 것으로 판단되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.595-598
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• 2004

This research seeks to derive the design rainfalls through the L-moment with the test of homogeneity, independence and outlier of data on annual maximum daily rainfall at 38 rainfall stations in Korea. To select the appropriate distribution of annual maximum daily rainfall data by the rainfall stations, Generalized Extreme Value (GEV), Generalized Logistic (GLO), Generalized Pareto (GPA), Generalized Normal (GNO) and Pearson Type 3 (PT3) probability distributions were applied and their aptness were judged using an L-moment ratio diagram and the Kolmogorov-Smirnov (K-S) test. Parameters of appropriate distributions were estimated from the observed and simulated annual maximum daily rainfall using Monte Carlo techniques. Design rainfalls were finally derived by GEV distribution, which was proved to be more appropriate than the other distributions.

• 한국농공학회논문집
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• 제46권3호
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• pp.31-42
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• 2004

This research seeks to derive the design rainfalls through the L-moment with the test of homogeneity, independence and outlier of data on annual maximum daily rainfall at 38 rainfall stations in Korea. To select the appropriate distribution of annual maximum daily rainfall data by the rainfall stations, Generalized Extreme Value (GEV), Generalized Logistic (GLO), Generalized Pareto (GPA), Generalized Normal (GNO) and Pearson Type 3 (PT3) probability distributions were applied and their aptness were judged using an L-moment ratio diagram and the Kolmogorov-Smirnov (K-S) test. Parameters of appropriate distributions were estimated from the observed and simulated annual maximum daily rainfall using Monte Carlo techniques. Design rainfalls were finally derived by GEV distribution, which was proved to be more appropriate than the other distributions.

• 한국농공학회논문집
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• 제48권5호
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• pp.17-27
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• 2006

The objective of this study is to induce the design floods by the methodology of L-moment including test of homogeneity, independence and outlier of the data of annual maximum flood flows for 12 water level gaging stations of South Korea. To select appropriate distribution of the data for annual maximum flood flows, the distributions of Wakeby and Kappa are applied and the appropriateness is judged by Kolmogorov-smirnov (K-S) test. The parameters of selected Wakeby and Kappa distributions are calculated by the method of L-moment and the design floods are induced. Through the comparative analysis using the relative root mean square errors (RRMSE) and relative absolute errors (RAE) of design floods, the result shows that the design floods by Wakeby distribution are closer to the observed data than those obtained by the Kappa distribution.

• 한국항공우주학회지
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• 제39권6호
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• pp.576-584
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• 2011

성공적인 발사체 개발을 위해서는 개발비용을 정확하게 추정하는 것도 중요하지만 연차별 예산 배분을 적절히 계획하는 것도 중요하다. 본 논문에서는 통계적 기법을 이용하여 개발기간 중 연차별 예산 배분에 대하여 분석하였다. 연차별 비용 모델링을 위해서 통계적 모델의 분석을 통해 적합성을 판단하여 베타분포모델을 선택하였고, 프로젝트의 설계와 기술의 성숙도로 추정이 가능한 모델을 개발하였다. 연차별 비용 모델의 타당성을 검증하기 위하여 우주왕복선 주 엔진(Space Shuttle Main Engine)의 실제 개발비용 분포와 본 모델을 통한 개발비용 분포의 비교 연구를 통해 적합성을 확인하였다. 또한, 본 논문의 개발 비용 모델을 한국형발사체 개발에 적용하여 연차별 소요 비용을 추정하였다. 본 논문에서 제시하는 연차별 분포 모델은 발사체뿐만 아니라 다른 대형복합시스템의 개발에도 활용이 가능할 것으로 예상된다.

• 한국대기환경학회지
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• 제2권2호
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• pp.60-65
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• 1986

Atmospheric particulates were collected at a site near the front gate of the Yonsei University using nine stages Andersen air sampler and the distribution of seasonal particle size was investigated. Rubber, Pb and Zn contents of the collected particulates in each stage were determined. Particle size distribution of atmospheric particulate, which was made by concentration distribution curve method, was usually divided into two groups, course (particles larger than 1 - 2 $\mu m in diameter$) and fine (particles smaller than 1 - 2 \mu m in diameter$) groups, regardless of sampling period. More than 80 percent of the total rubber contents in atmospheric particulates were larger than $5 \mu m$ in diameter, meaning that most of rubber particles were originated from tire tread. After benzene extraction for 4 hrs, the extracts were analyzed by Curie-point pyrolysis gas chromatography for rubber content. Pb and Zn contents were determined by atomic absorption spectroscopy. The annual average concentration of rubber particles was $4.2 \mu g/m^3$, which corresponded to 2.2% of the annual average total suspended particulates. Average concentration of styrene brtadiene rubber was about five times that of natural rubber. Annual average concentrations of Pb and Zn were $1.2 \mu g/m^3 and 0.4 \mu g/m^3$ respectively, which corresponded to about 0.7% and 0.2% of the annual average total suspended particulates.