http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
생태자연도 등급 하락에 영향을 미치는 인위적 토지피복 변화 분석
최철현,임치홍,이성제,서현진 한국환경복원기술학회 2019 한국환경복원기술학회지 Vol.22 No.6
The first grade zones in Ecology and Nature Map are important regions for the conservation of the ecosystem, but it would be degraded by various anthropogenic factors. This study analyzes the relation- ship between potential land cover change and degradation of the first grade zones using land cover transition probability. As a result, it was shown that most of the first grade zones with degraded were converted from forest to urban(5.1%), cropland(27.2%), barren(11.0%) and grass(27.5%) in Gangwon and forest to urban(18.0%), cropland(15.3%), grass(28.4%), barren(12.3%) in Gyeonggi. The result of the logistic regression analysis showed that the probability of degradation of first grade zone was high- er in area where was expected the higher probability of urban, cropland, barren, grass transition. The barren transition probability was the most influential and grass was the next highest. There were re- gional differences in the probability of urban transition and cropland transition, and the urban transition probability was more influential in Gyeonggi-do. This is because development pressure such as housing site development is high in Gyeonggi-do. Due to the limitations of the Act on Mountain Districts Management, even in the first grade zones, the grade may be degraded. Therefore, if Ecology and Nature Map are used to prevent deforestation or conversion of mountainous districts, it may contribute to the preservation of the ecosystem.
최철현,박순룡,오범환 한국광학회 2000 한국광학회지 Vol.11 No.6
방향성 결합기의 성능개선을 위해 입사광과 결합기 도파모드와의 전이계수를 조절하여 $Cv_e$ 와 $Cv_o$ 의 차이, $Cv_e-Cv_o$ 를 줄임으로써 소멸비를 향상시키는 방안을 제안한다. 입력 도파로와 결합기의 접합부에서 입력 도파로를 수평 이동시키는 방식과 곡선형 입력 도파로의 도파모드 편향성을 이용한 방식을 혼합하여 적용해서 전이계수와 손실을 최적화하고 소멸비와 제작상의 허용오차를 월등히 개선한다. 주어진 도파로 구조의 경우 유효굴절률법과 MPA를 사용하여 분석한결과 곡률 반경이 $300\mu\textrm{m}$이고 접합위치의 수평이동이 $0.1\mu\textrm{m}$인 입력 도파로의 채택으로 최대 소멸비는 -39 dB로 낮출 수 있으며 -30dB 소멸비 기준에서의 방향성 결합기의 결합길이에 대한 제작 허용오차 폭은 $57.19\mu\textrm{m}$에 이르게 되었다. 이는 수평 이동을 고려하지 않는 직선형 입력 도파로에 비하여 최대 소멸비의 향상은 6dB 제작 허용오차 폭은 $13.9\mu\textrm{m}$ 향상시킨 결과이다. We propose a novel design concept to improve extinction ratio by minimizing $Cv_e-Cv_o$ . Improvements of loss and fabrication error limit are also obtained by this hybrid design of the lateral shift and curved waveguide to control transfer coefficients, $Cv_e and Cv_o$ . The concept of lateral shift merges two transfer coefficients, and additional curved waveguide controls mode profile asymmetrically to help this minimizing effect of $Cv_e-Cv_o$ with no serious decrease in transfer efficiency. For a given InP based waveguide structure, the mode propagation analysis with an effective index approximation provided a calculational improvement of extinction ratio to -39 dB and fabrication error limit to $57.19\mu\textrm{m}$, with a structure design of $300\mu\textrm{m}$ waveguide curvature and $0.1\mu\textrm{m}$lateral shift. shift.
최철현,장인영,한상학,강성룡 (사)지오에이아이데이터학회 2023 GEO DATA Vol.5 No.4
In this study, we utilized Google Earth Engine to construct, for the first time in South Korea, a long-term (1986-2021) continuous time series of land cover maps with a spatial resolution of 30 meters. Derived from the surface reflectance data of the Landsat satellite series, a total of 44 input variables were generated, including various spectral bands and indices related to land cover. For accuracy verification of the maps, 4,824 reference data were established using areas where land cover remained unchanged, identified by comparing the most recent (2018) and historical (1988) land cover maps from the Ministry of Environment. The Random Forest model was employed to classify seven land cover types (settlements, cropland, forest land, grassland, wetlands, bare land, and water bodies), with an overall accuracy of 0.97 and a Macro F1-score of 0.91, indicating a generally high performance of the model. However, considering the annual variability, potentially due to unidentified or untraceable errors, a composite land cover map dataset, integrated in five-year intervals, was suggested to ensure the generation of stable data.