• 대한원격탐사학회지
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• 제37권5_1호
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• pp.1149-1161
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• 2021

컴퓨터 비전 기술이 위성영상에 적용되면서, 최근 들어 딥러닝 영상인식을 이용한 구름 탐지가 관심을 끌고 있다. 본연구에서는 SPARCS (Spatial Procedures for Automated Removal of Cloud and Shadow) Cloud Dataset과 영상자료증대 기법을 활용하여 U-Net 구름탐지 모델링을 수행하고, 10폴드 교차검증을 통해 객관적인 정확도 평가를 수행하였다. 512×512 화소로 구성된 1800장의 학습자료에 대한 암맹평가 결과, Accuracy 0.821, Precision 0.847, Recall 0.821, F1-score 0.831, IoU (Intersection over Union) 0.723의 비교적 높은 정확도를 나타냈다. 그러나 구름그림자 중 14.5%, 구름 중 19.7% 정도가 땅으로 잘못 예측되기도 했는데, 이는 학습자료의 양과 질을 보다 더 향상시킴으로써 개선 가능할 것으로 보인다. 또한 최근 각광받고 있는 DeepLab V3+ 모델이나 NAS(Neural Architecture Search) 최적화 기법을 통해 차세대중형위성 1, 2, 4호 등의 구름탐지에 활용 가능할 것으로 기대한다.

• Fisheries and Aquatic Sciences
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• 제18권3호
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• pp.235-240
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• 2015

Seasonal variation in the prevalence of norovirus in oysters Crassostrea gigas was investigated and compared to levels of Escherichia coli, a fecal indicator in oysters. Oysters were collected from Iwon-myeon, Taean-gun, Korea, a primary production area for European Union export of oysters between 2013 and 2014. We observed seasonality in the prevalence of norovirus in oysters, with a higher prevalence and viral load detected during winter months. Oysters taken from production areas that complied with the European Union standard for raw consumption (< 230 MPN/100 g of E. coli) had 22.1% of the samples test positive for norovirus (15/68 samples). However, norovirus was not detected in any of the samples (0%, 0/4 samples) that were collected from production sites that exceeded the standard fecal contamination level for raw consumption (> 230 MPN/100 g of E. coli). These results indicated that there is a negative correlation between the prevalence of norovirus and high levels of E. coli in oysters. Therefore, our results suggest that current food safety guidelines using only a bacterial fecal contamination indicator, E. coli, may not adequately assess shellfish production areas for viral and bacterial contamination.

• International Journal of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.171-176
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• 2023

What we have in common worldwide today is economic difficulties due to high inflation and uncertainty in the financial industry. The root cause of this is the war between Russia and Ukraine. The war between Russia and Ukraine is not simply a war between two countries. The United States and the European Union are providing military aid such as missiles to Ukraine, and Russia is attacking Ukraine by introducing UAVs (unmanned aerial vehicles) from Iran. A prominent weapon in this Russia-Ukraine war is the UAVs used in Russia. It is predicted that the form of war using UAVs will gradually expand in the future based on stealth. In addition, UAVs will continue to be used due to the fact that they can cause serious damage to the other country without harming their own lives, and because they have good cost-effectiveness. In this study, UAVs based on autonomous driving were studied. The target countries of the study include the United States, the European Union, China, and Iran, and the UAVs used in these countries have characteristics that can represent the world. In this study, the main specifications of major UAVs in use in major countries were investigated. In addition, the future technology and development direction were described through specifications and characteristics of UAVs currently in operation in major countries.

• 한국환경복원기술학회지
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• 제23권1호
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• pp.37-48
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• 2020

This study was aimed to design core areas applied by the global conservation criteria to promote the public awareness to the protected areas and the value cognition of the Key Biodiversity Areas (KBAs), targeting the Mt Seorak, according to the designation of globally important biodiversity areas. As a method for carrying out this study, the biota were cataloged through literature reviews and field trips. With applied by the Global Red List criteria of the International Union for Conservation of Nature (IUCN), only nine species were categorized in the studied area; plants were classified into six species as follows: Megaleranthis saniculifolia ohwi, Bupleurum euphorbioides Nakai, Hanabusaya asiatica Nakai, Thuja koraiensis Nakai, Leontopodium leiolepis Nakai, Androsace cortusaefolia Nakai, fish was classified one species as follow: Pungitius sinensis Tanaka, and the mammal was classified as two species as follows: Hydropotes inermis, Naemorhedus caudatus. According to the occupation area (EoO, Extent of Occurrence) and Minimum Viable Population(MVP), the size of protected area was 234.56㎢ for plants, 235.07㎢ for mammals, and 0.14㎢ for fish, and the Key Biodiversity Area (KBA) of Mt. Seolak suggested as 286.72㎢.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2002년도 추계 학술발표회 논문집
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• pp.119-124
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• 2002

We consider a multi-state flow network consisted of undirected links and focus on how to find efficiently the union of minimal paths transmitting a required flow when minimal paths are known.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제26권1호
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• pp.59-73
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• 1998

Sediment samples from five stations at the Shihwa Lake sewage outfall, west cost of Korea, were collected to evaluate the effect of the outfall on benthic foraminifers. Heavy metal (Cu and Zn) polluted the eastern part of the Shihwa Lake, adjacent to the Shihwa-Banwol Industrial Complexes, shows barren or nearly barren of benthic foraminifers, and the lowest number of species both at the core top and downcore. Excepting for the barren zone, pyritized benthic foraminifers abundantly occur both at the surface and downcore sediments in the western part of the Shihwa Lake, suggesting that foraminiferal disease by anoxic bacteria. Recent intrusion of pollutants form the Shihwa-Banwol Industrial Complexes and adjacent six major streams severely polluted the Shihwa Lake as shown by the low abundance (number/10 g) of benthic foraminifers, low number of Ammonia beccarii, low species diversity, and absence of both Elphidium spp. and ostracodes at the surface sediments compared of both downcore. Except the barren zone, both pyritized and non-pyritized Ammonia beccarii occur dominantly in the surface sediments and downcore. Elphidium spp. (either pyritized or non-phyritized) do not occur in the surface sediments of whole stations. However, they occur from the entire downcore sediments except in the eastern part of Shihwa Lake. Arenaceous foraminifers do not inhabit in the heavily polluted areas as evidenced by the occurrence of relatively deep core depth (11-15 cm). Ostracodes occur at the downcore sediments, but they do not occur at the surface sediments. Ostracodes also do not occur at the heavily polluted areas in the eastern part of the Shihwa Lake both at the surface and downcore sediments, indicating that the abundance of ostracodes also can be used for a pollution indicator.

• 대한원격탐사학회지
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• 제38권6_2호
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• pp.1623-1631
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• 2022

유출유는 해양 생태계에 큰 위협이 되므로 피해 최소화를 위해 신속한 현황정보파악이 필요하다. 위성원격탐사는 항공기에 비해 광역적 모니터링이 가능하기 때문에 시공간적 범위에서 장점을 가진다. 최근에는 딥러닝 영상인식 기술의 발전으로 인해 딥러닝을 활용한 유출유 탐지의 필요성이 대두되고 있으나, 기존의 Synthetic Aperture Radar (SAR) 영상 위주의 유출유 탐지와는 달리 고해상도 광학영상에 딥러닝 기법을 적용하는 경우는 많지 않았다. 이에, 본 연구에서는 PlanetScope 위성의 광학영상을 활용하여 유출유 레이블을 제작하고, 이를 기반으로 DeepLabV3+모델을 활용하여 유출유 탐지 모델을 구축하였으며, 암맹평가에서 정확도 0.885, 정밀도 0.888, 재현율 0.886, F1점수 0.883, 평균 교집합 대 합집합 비율(Mean Intersection over Union, mIOU) 0.793 등의 상당히 높은 정확도를 나타냈다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2001년도 춘계학술대회 학술발표 논문집
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• pp.34-37
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• 2001

Park et al. [Proc. KFIS Fall Conf. 10(2) (2000), 59-62] defined fuzzy ${\gamma}$-open sets by using an operation ${\gamma}$ on a fts (X, $\tau$) and investigated the related fuzzy topological properties of the associated fuzzy topology $\tau$/seb ${\gamma}$/ and $\tau$. As generalizations of the notion of fuzzy ${\gamma}$-closed sets, we define gf. ${\gamma}$-closed sets and g*f. ${\gamma}$-closed sets and study basic properties of these sets relative to union and intersection. Also, we introduce and study two classes of ftss called fuzzy ${\gamma}$-T* and fuzzy ${\gamma}$-T$_{1}$2/ spaces by using the notions of gf. ${\gamma}$-closed and g*f. ${\gamma}$-closed sets.

• 한국수소및신에너지학회논문집
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• 제19권2호
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• pp.171-181
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• 2008

There are several methods for the gas hydrate production such as spraying water with countercurrent gas flow, stirring water-gas mixture, and flowing water with micro-bubble, etc. These days it has been widely studied for the gas hydrate production method, having low energy consumption and high efficiency. In this paper, patents in the gas hydrate production method were gathered and analyzed. The search range was limited to the open patents of USA, European Union (EP), Japan (JP), and Korea (KR) from 1991 to 2007. Patents were gathered by using keywords searching and filtered by crucial criteria. The trends of the patents were analyzed by the years, countries, companies, and technologies.

• 한국포장학회지
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• 제15권3호
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• pp.93-98
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• 2009

Migration levels of plasticizers, di-n-butyl phthalate (DBP), benzyl-butyl phthalate (BBP), di-n-octyl phthalate(DNOP), di-iso-decyl phthalate (DIDP) and di-iso-nonyl phthalate (DINP), di-(2-ethylhexyl) adipate (DEHA), from 46 poly(vinyl chloride) (PVC) wrap films and 54 PVC gaskets into food simulants were determined using gas chromatography/mass spectrometry (GC/MS). The method was validated with limit of detection (LOD) of $0.01{\sim}0.02\;{\mu}g/mL$ for DBP, BBP, DNOP and DEHA, and $2\;{\mu}g/mL$ for DIDP and DINP. The linearity were found to be > 0.99 for all the compounds in concentration range of $0.1{\sim}81.4\;{\mu}g/mL$, and overall recoveries were ranged from 90.4 ~ 99.6%. DBP, BBP, DNOP, DEHA, DIDP and DINP were not detected in food simulants, except 1 wrap sample from which 0.28 and $0.99\;{\mu}g/mL$ of DEHA were detected respectively when tested with 20% ethanol and n-heptane as food simulants. These values were below the regulatory limitation in European Union (EU).