• Journal of Advanced Marine Engineering and Technology
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• 제37권6호
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• pp.603-610
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• 2013

유한요소해석을 수행하여 조향장치용 타이로드 볼 조인트의 주름 형상 더스트 커버의 응력과 변형을 평가하였다. 조립상태 및 작동상태 하에서 기존 설계안의 더스트 커버를 해석한 결과, 밀봉성이 우수하고 최대응력은 인장강도보다 낮게 나타났다. 더스트 커버의 최대응력을 저감시키기 위하여 형상설계변수를 선정하고, 다구찌 기법을 사용하여 최적형상을 구하였다. 도출된 최적설계안의 작동상태에서의 최대응력은 초기설계안 대비 22 % 감소되는 것으로 나타났다. 본 연구에서 제시된 방법을 사용하면 더스트 커버의 평가 및 설계를 효율적으로 할 수 있다.

• 대한원격탐사학회지
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• 제20권4호
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• pp.253-259
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• 2004

본 연구의 목적은 다양한 공간해상도의 위성영상(Landsat + ETM, KOMPSAT-1 EOC, ASTER VNIR, IKONOS 전정색 및 다중분광)을 비교하여 각 영상에서의 농업관련 정보의 분류기준을 파악하고자 하였다 여기서 농업관련 정보는 식별이 가능한 농업지역, 작물형태, 농업시설과 구조물을 대상으로 하였다. 그 결과는 국토지리정보원과 환경부의 분류기준과 비교하였으며, 본 연구에서 설정한 농업관련정보의 기준을 IKONOS 영상에 적용하여 농업관련 토지피복도를 작성하였다. IKONOS 영상에 대하여 분석된 결과는 KOMPSAT-2의 농업분야 활용에 적용될 것이다.

• 한국생산제조학회지
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• 제24권4호
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• pp.469-474
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• 2015

In ultrasonic spray pyrolysis deposition, a precursor solution is evaporated by an ultrasonic atomizer, then gas-carried into a furnace where the solute is separated from the water vapor. After condensation, polymerization, and nucleation, the solute oxide forms a thin film. To improve the deposition efficiency, the ultrasonic atomizer was studied to optimize the evaporated gas flow. The vat cover was redesigned, using three versions with different inlet factors being tested through a computational fluid dynamic analysis as well as a water evaporation experiment. The atomization rate with a hemispherical cover with a $30^{\circ}$ inlet was found to be 2.4 times higher than that with the original. This improvement was verified with fluorine-doped tin oxide spray pyrolysis deposition. The film obtained with the modified vat cover was 2.4 times thicker than that obtained with the original vat cover.

• 한국전산유체공학회지
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• 제11권3호
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• pp.52-58
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• 2006

A numerical investigation is made of air flow in a spinner equipment used for cleanning and drying flat display panels. A unique feature of the spinner under question is the placement of a torus plate cover over the rotating plate. The turbulent flow is driven by rotation of a large disk and suction by the exhaust system connected to vacuum chamber. The flow is modelled as an axisymmetric two-dimensional flow and computation is conducted by using the FLUENT package with a version of k-$\varepsilon$ turbulence model. The required capacity of the exhaust system is assessed numerically. The usefulness of the cover in controlling air flow circulation is examined. A computational trouble shooting is attempted to resolve the problem of panel rising which occurred in real experiment.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.75-77
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• 2003

The spatial distribution of snow cover area is a crucial input to models of hydrology and climate in alpine and other seasonally snow covered areas.The objective in our study is to develop a rapidly automatic and high accuracy snow cover mapping algorithm applicable for the Tibetan Plateau which is the most sensitive about climatic change. Monitoring regional snow extent reqires higher temoral frequency-moderate spatial resolution imagery.Our algorithm is based AVHRR and MODIS data and will provide long-term fraction snow cover area map.We present here a technique is based on the multiple endmembers approach and by taking advantages of current approaches, we developed a technique for automatic selection of local reference spectral endmembers.

• 한국농림기상학회지
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• 제24권4호
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• pp.318-329
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• 2022

본 연구를 통해 설계된 테스트베드 지역의 식물계절 관측과 적설 탐지는 반복 이미지 학습 및 정량적 RGB 분석을 통해 정확도 높은 산림 식물계절 및 적설 관측 기반을 마련하였다. 무인카메라 기반 식물계절 및 적설 탐지 기술 개발은 복잡한 산악지형이라는 특수한 환경에서 다양한 고도의 환경 데이터를 실시간 수집하는 체계를 구축함으로써 산림환경 연구를 위한 기초 데이터를 수집하는 계기가 되었다. 첨단기술을 활용한 주요 산악지역의 식물계절 변화 탐지 연구는 산림청에서 제공하는 개화 및 개엽 예측 정보의 검증과 산림휴양쾌적지수 고도화 등에 활용 가능하며, 향후 농림위성의 NDVI 등 영상 이미지의 검⋅보정용 자료로써 활용 가치가 매우 높다. 무인카메라 활용 기술은 산림 식물계절 및 적설 탐지뿐만 아니라 산림재해 감시 및 산림관리 등 다양한 산림분야에서도 활용될 수 있을 것으로 기대된다.

• 한국토양환경학회지
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• 제1권1호
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• pp.103-109
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• 1996

일반 및 특정폐기물 매립지에서 복토층의 중요성은 매립지의 바닥층 만큼 강조되지는 않는 것 같다. 그러나 실제로 매립지의 파괴 원인중에 가장 커다란 영향을 미치는 것은 복토층 설치의 실패에서 온다고 볼 수 있다. 특히 복토층 기능은 우수를 지표면으로 유출증진하여 매립장 안으로 침투 억제시키며, 폐기물의 노출시 자연환경 위생에 대하여 완충작용을 하며, 매립지의 침하 및 침강을 억제하는데 있다. 본 연구는 겨울철 동결/융해에 따른 폐기물 매립지 최종복토의 거동을 수행하였으며, 폐기물 매립지에서와 같은 조건을 부여하기 위해 거대한 Lysimeter를 설치하여 실제로 최종복토에 쓰여지는 물질로 세가지 실험을 수행하였다. 실험결과는 동결/융해에 따른 점토층의 변화를 묘사하고 있으며 또한, 매립지에서의 동결깊이에 따른 복토층의 파괴는 점토의 물리 적, 공학적인 측면에 영향을 주며 이러한 영향은 매립지 설계시 고려되어야 한다고 본다. 본문은 실험에 사용되어진 복토층의 물질, 복토층의 묘사와 그들의 실험결과에 대한 결과분석 및 결론을 설명하고 있다.

• 한국작물학회지
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• 제52권3호
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• pp.341-347
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• 2007

Chinese milk vetch (CMV) is a winter legume that is commonly used as cover crop in Korea. Kill date of cover crop for addition into soil affects N content in cover crop and N availability in soil. This study was conducted to evaluate the effect of CMV as green manure cover crop according to kill dates before growing corn without artificial fertilizer. Top of CMV cut three times on 13 April, 27 April, and 11 May were added into soil at a rate of 600 kg per 10a. Sugar content in CMV litter was persistently decreased from mid-April to late-May. The decrease of sugar content might be due to the transformation into starch and/or other storage or structural constituents. The decreased amount of sugars was greater than 12% and the increased amount of starch was less than 0.2%. Concentration of $NH_4^+$ in soil treated by CMV litter cut on May 11 was slightly higher than that in the treatment with early-cut (April 13) CMV, the concentration at 28 and 49 DAT (days after treatment) was higher in the treatment with late-cut CMV litter. Regardless of cut (kill) date of CMV, the phosphatase activity in the treatment of CMV litter was higher compared to the untreated control. Soil dehydrogenase activity was increased steadily by addition of CMV litter implying total microbial activities in the soil were increased. Our results demonstrate that the status of cover crop species at kill date is an important factor influencing soil enzyme activities derived from microorganisms. Therefore, the optimal kill date of cover crop should be examined to improve the efficiency of cover crop as green manure crop regarding the practical sequence in cropping system.

• 농업과학연구
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• 제47권4호
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• pp.933-940
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• 2020

Land-use change matrix data is important for calculating the LULUCF (land use, land use change and forestry) sector of the national greenhouse gas inventory. In this study, land cover changes in 2004 and 2019 were compared using the Wall-to-Wall technique with a land cover map of Sejong City from the Ministry of Environment. Sejong City was classified into six land use classes according to the Intergovernmental Panel on Climate Change (IPCC) guidelines: Forest land, crop land, grassland, wetland, settlement and other land. The coordinate system of the land cover maps of 2004 and 2019 were harmonized and the land use was reclassified. The results indicate that during the 15 years from 2004 to 2019 forestlands and croplands decreased from 50.4% (234.2 ㎢) and 34.6% (161.0 ㎢) to 43.4% (201.7 ㎢) and 20.7% (96.2 ㎢), respectively, while Settlement and Other land area increased significantly from 8.9% (41.1 ㎢) and 1.4% (6.9 ㎢) to 35.6% (119.0 ㎢) and 6.5% (30.3 ㎢). 79.㎢ of cropland area (96.2 ㎢) in 2019 was maintained as cropland, and 8.8 ㎢, 1.7 ㎢, 0.5 ㎢, 5.4 ㎢, and 0.4 ㎢ were converted from forestland, grassland, wetland, and settlement, respectively. This research, however, is subject to several limitations. The uncertainty of the land use change matrix when using the wall-to-wall technique depends on the accuracy of the utilized land cover map. Also, the land cover maps have different resolutions and different classification criteria for each production period. Despite these limitations, creating a land use change matrix using the Wall-to-Wall technique with a Land cover map has great advantages of saving time and money.

• 한국대기환경학회지
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• 제3권1호
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• pp.47-54
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• 1987

A new method for designing air pollution monitoring newtork is presented in this study. In this method, the magnitudes and the correlation coefficients of predicted concentrations in each grid points are examined and the monitoring stations are assigned to those stations which cover the damage cost the most. This method was applied to the Ulsan-Onsan Industrial Complex. This method turned out to be much more efficient than the method of TM coordinates and the method of concentric circles prescribed in the Standard Methods for Pollution Measurement as well as the existing monitoring system established in the area. The 21 stations selected by the method of TM coordinates could cover only 64.4% of the damage cost in the area, the 16 stations by the method of concentric circles 72.1%, and the existing 21 stations 67.8%, while 11 stations were enough to cover 90% of the damage cost in the area with this method. It also was found that this method required only 24 stations to cover the entire area.