• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.1-2
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• 2021

3D NAND 플래시 메모리는 플래너(2D) NAND 셀을 적층하는 방식으로 단위 면적당 고용량을 제공한다. 하지만 적층 공정의 특성상 각 레이어별 또는 셀 위치에 따라 오류 발생 빈도가 달라질 수 있는 문제가 있다. 이와 같은 현상은 플래시 메모리의 쓰기/지우기(P/E) 횟수가 증가할 수록 두드러진다. SSD와 같은 대부분의 플래시 기반 저장장치는 오류 교정을 위하여 ECC를 사용한다. 이 방법은 모든 플래시 메모리 페이지에 대하여 고정된 보호 강도를 제공하므로 물리적 위치에 따라 에러 발생률이 각기 다르게 나타나는 3D NAND 플래시 메모리에서는 한계를 보인다. 따라서 본 논문에서는 오류 발생률 차이를 보이는 페이지와 레이어를 분류하여 각 영역별로 차별화된 보호강도를 적용한다. 우리는 페이지와 레이어별로 오류 발생률이 현저하게 달라지는 3K P/E 사이클에서 측정된 오류율을 바탕으로 페이지와 레이어를 분류하고 오류에 취약한 영역에 대해서는 패리티 데이터를 추가하여 차별화된 보호 강도를 제공한다. 오류 발생 횟수에 따른 영역 구분을 위하여 K-Means 머신러닝 알고리즘을 사용한다. 우리는 이와 같은 차별화된 보호정책이 3D NAND 플래시 메모리의 신뢰성과 수명향상에 기여할 수 있는 가능성을 보인다.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.263-270
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• 2023

The Ukraine-Russia war is a testing ground for High-Tech weapons and the first full-scale drone warfare. The Ukrainian military has been aggressively deploying a variety of reconnaissance and attack drones on the battlefield, and more recently, FPV drones, also known as racing drones, have been fitted with bombs as a game-changer in small-unit combat. To better understand these FPV drones, this article reviews their definition, aircraft components, and key characteristics, and draws implications from the Ukrainian military's FPV combat experience. In the future, the combination of artificial intelligence and swarming technology will make FPV drones even more lethal. Accordingly, the need to develop FPV drones suitable for the future operational environment on the Korean Peninsula is increasing, and follow-up research is needed to specify fighting methods and optimize related technologies.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.51-51
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• 2020

콩의 원산지는 만주를 중심으로한 동북아시아를 원산지로 추정하고 있으며, 동아시아인 한국, 중국, 일본의 주요 식재료로 다양하게 이용되어왔다. 콩은 단백질과 지방의 공급원으로서 뿐 아니라 최근에는 콩의 생리활성 물질이 항암효과, 골다공증, 신장질환과 같은 질병예방에도 효과가 있는 것으로 알려지면서 활용가능성이 높아지고 있다. 본 연구는 유전자원센터에 보존 중인 콩 수집단에서 농업형질, 기초정보 등을 토대로 핵심집단을 작성하고 그 중 한국, 중국, 일본 수집단 각 425, 93, 42자원의 개화일수, 생육일수, 주당협수, 100립중, 주당수량과 같은 양적형질을 비교하였다. 개화일수와 생육일수는 중국수집 자원에서 평균38일, 107일로 가장 빠르며, 한국수집 자원은 평균 53일, 127일로 가장 늦었다. 협당립수는 중국수집 자원에서 협당 평균3립으로 가장 많았으며, 한국과 일본 수집자원은 각 2.3과 2.4립으로 유사하였다. 주당협수는 한국 수집자원에서 주당 평균 327.4개로 가장 많고 일본이 248.0개 중국이 224.4순으로 조사되었다. 100립중은 일본 수집 자원이 평균 33.6g으로 대립이 많고 한국 26.5g , 중국 21.1g 이었다. 주당수량은 한국 수집자원이 평균 119.8g, 일본 84.2g, 중국 76.8g순이었다. 이들 5개 양적형질을 토대로 군집분석한 결과 한국 자원은 대다수가 C3 그룹에 속하고, C1 그룹에 일부가 속하였으며, 일본 자원은 C3 그룹과 C2 그룹에, 중국 자원은 C2 그룹에 속하여 한국과 일본자원이 유사하고 중국자원과는 차이를 보이는 것으로 나타났다. 이러한 특성조사 결과는 자원의 수집, 도입시 다양성 확보를 위한 기초정보로 이용할 수 있다.

• Smart Media Journal
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• v.12 no.11
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• pp.36-47
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• 2023

Industrial Control System(ICS), which controls facilities at major industrial sites, is increasingly connected to other systems through networks. With this integration and the development of intelligent attacks that can lead to a single external intrusion as a whole system paralysis, the risk and impact of security on industrial control systems are increasing. As a result, research on how to protect and detect cyber attacks is actively underway, and deep learning models in the form of unsupervised learning have achieved a lot, and many abnormal detection technologies based on deep learning are being introduced. In this study, we emphasize the application of preprocessing methodologies to enhance the anomaly detection performance of deep learning models on time series data. The results demonstrate the effectiveness of a Wavelet Transform (WT)-based noise reduction methodology as a preprocessing technique for deep learning-based anomaly detection. Particularly, by incorporating sensor characteristics through clustering, the differential application of the Dual-Tree Complex Wavelet Transform proves to be the most effective approach in improving the detection performance of cyber attacks.

• Environmental and Resource Economics Review
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• v.33 no.1
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• pp.59-86
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• 2024

Recently, research on city gas demand is increasing by reflecting the characteristics of each region. The similarity of the social structure of the adjacent region and the density of the supply infrastructure induce spatial correlation with the clustering that has a microscopic relationship between regions. Accordingly, as a result of analyzing the spatial correlation after dividing the demand for city gas for civilian use into a total of 54 regions based on the jurisdiction of 34 city gas companies, it was confirmed that there was a positive spatial correlation from a global and local perspective. In this study, the demand for city gas for civilian use for 54 regions from January 2014 to December 2022 was composed of panel data, and the spatial panel regression analysis and the general panel regression analysis were compared, and it was found that the spatial error model (SEM) was the most suitable model. This presents policy and practical implications by confirming that the demand for city gas for civilian use in one region has a significant relationship with the adjacent region.

• Korean Journal of Environment and Ecology
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• v.25 no.2
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• pp.132-144
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• 2011

We studied the forest environment and characteristics of bird community between April and September of 2010 on the Hyangjeokbong area(A), Baekryunsa area(B) and Anseong area(C), all in the Deogyusan National Park. Hyangjeokbong area of the high latitude ridge was characterized by the Taxus cuspidata and Abies koreana etc., and deciduous broadleaf forest species, such as the Quercus mongolica, with abundance of subalpine zone coniferous trees, the Hemerocallis fulva and the Rhododendron schlippenbachii, while the areas Baekryunsa and Anseong were primarily characterized by deciduous broadleaf forests, with the valleys showing Fraxinus mandshurica colonies. In terms of the DBH(diameter at breast height) of trees, between 11 and 20cm showed the highest frequencies, while over 30cm was the highest in Baekryunsa area and the lowest in Hyangjeokbong area. Furthermore, in terms of coverage in relation to layers, in Hyangjeokbong area, the coverage volume of the lower layer was very high, in Baekryunsa area, the coverage volume of the middle layer between 8 and 12m was the highest, and in Anseong area, the coverage volume of the upper layer over 18m was the highest. A total of 53 bird species were observed during the study period at the Deogyusan National Park. The numbers of species and density of areas were 25 species and 45.20 Ind./km for Hyangjeokbong area, 50 species and 58.63 Ind./km for Baekryunsa area and 35 species and 66.89 Ind./km for Anseong area, with Baekryunsa area showing the highest number of species and Anseong area showing the highest level of density. In terms of dominant species, in Hyangjeokbong area, Cettia diphone, along with species which inhabit in grassland and shrubs, were the dominant species, and species which live in the canopy layer, including the Aegithalos caudatus, were found to be dominant in Baekryunsa and Anseong areas. For guild structure, bush nesting guild and bush foraging guild species were the highest in all areas, and the hole nesting guild and the air foraging guild species showed the lowest proportion. This seems to be the result of the low number of trees with diameter at breast height of over 30cm, which results in the lack of nesting grounds for hole nesting guild species.

• Korean Journal of Environmental Biology
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• v.30 no.1
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• pp.15-25
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• 2012

From April to November 2009, we performed field investigation to survey the characteristics of fish fauna and fish community structure inhabited in Yongdam reservoir in the upper Geumgang, which is changed into flat-water zone from flow-water zone by blocking the continuity by the gigantic submerged weir built in the upstream of Geumgang. 15 species belonging to 8 families were collected from natural habitat (St. 1) where its natural characteristics is well preserved, and 11 species were korean endemic fish species. 24 species belonging to 10 families were collected at the down region of Yongdam dam (St. 3), which might be affected by the change of water environment due to the dam, and 11 species were korean endemic fish species. On the other hand, 20 species belonging to 7 families were collected inside Yongdam reservoir (St. 2) which is changed into flat-water zone from flow-water zone by the dam reservoir, and 6 species were korean endemic fish species. In the dam reservoir, due to Yongdam dam built in the upper Geumgang, the original flow-water zone fish such as $Acheilognathus$ $koreensis$, $Pseudopungtungia$ $nigra$, $Coreoleuciscus$ $splendidus$, and $Gobiobotia$ $macrocephala$ were disappeared, and instead, the kinds of fish habitating in the flat-water zone tend to increase rapidly, such as $Carassius$ $auratus$, $Opsarichthys$ $uncirostris$ $amurensis$, $Hemiculter$ $eigenmanni$, $Zacco$ $platypus$, and $Lepomis$ $macrochirus$. Relative abundance of the insective fish was 66.7% at St. 1, 40.0% at St. 2, and 54.2% at St. 3. In order to preserve endemic fish species and aquatic ecosystem, it is desirable to minimize the artificial installation in the upper river, such as a large scale dam which can affect the habitat and if inevitable, it is required to prepare preservation measures when building facilities.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.524-540
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• 2013

After the construction of the Geum River estuary dam, we investigated the ecological property of phytoplankton community with physicochemical property in 9 stations of Geum River estuary 4 times seasonally in 2010 about the environmental changes through the change of phytoplankton. Physicochemical property seems to show eutrophication which developed from the tendency of accruing of the nutrients (those involved in intermittency of freshwater which flows from the dike and the surrounding cities), caused by the changing of tidal flow, the decreasing of the inflow of seawater after the construction of the Geum River estuary dam (dike). A total of 233 species of species composition of phytoplankton emerged, showing a highly increased result compared to that of the former research. The reason for the increase in number is considered as a phenomenon resulting from the mix of blackish and freshwater marine species in the flow of intermittency of freshwater discharge. Also, the standing crops of phytoplankton considerably increased compared to when the dike had not yet been built. Highly affected by the discharge of occasional freshwater, the diatoms of blackish water zone dominated in spring and winter, while freshwater species appeared to dominate in summer and autumn. The species diversity showed over 2.0 except in winter season. After a cluster analysis, the result showed that the Geum River estuary was influenced by runoff from cities like Gunsan, the sewage which flows from Gyeongpo River, and the intermittency of freshwater discharge from the Geum River estuary dam.

• The Korean Journal of Malacology
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• v.24 no.3
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• pp.215-228
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• 2008

This study was performed to find out the community structure of macrobenthos and the environmental factors around Munseom coastal water in Jeju Island from June to December, 2007. Mean temperature and mean salinity were $19.6^{\circ}C$ and 34.03 psu, indicating stable water masses. Concentrations of DO, COD and SS were as low as those in the standard sea-water-quality classes I. Chlorophyll a concentrations ranged from 0.40 to 1.09 mg/L (mean, 0.69 mg/L), and higher concentration was observed in December rather than in June due to a blooming in winter. The mean concentration (their ranges are in parentheses) of nitrate, phosphate, and silicate were 0.15 mg/L (0.073-0.264 mg/L), 0.01 mg/L (0.004-0.011 mg/L) and 0.23 mg/L (0.039-0.464 mg/L), respectively. The values were higher near the Munseom due to influxes from the land. Of the 112 species that were identified, 40 species (36.0%) were Mollusca; 33 (28.8%) were Cnidaria; 13 (11.7%) were Porifera; 8 (7.2%) were Arthropoda and 17 species (15.3%) were others including Echinodermata. Density and biomass were estimated to be 4,340 individual/$m^2$ and $53,107.8\;gwwt/m^2$ respectively. Anthozoa was the most dominant group in abundance ($2,132\;ind./m^2$) as well as in the number of species, whereas Cnidaria was predominant in biomass ($37,630.9\;gwwt/m^2$). The dominant species were Dendronephthya gigantea, Scleronephthya gracillimum, Anthoplexaura dimorpha, Dendronephthya castanea, Thecocarpus niger, Dendronephthya spinulosa, Dendronephthya putteri, and Acabaria bicolor in the depth of 10-30 m. The seasonal variations of the number of individual and biomass of Cnidaria and Mollusca were observed. There was a slow increment in June, a decrement in October, and a drastic increasing in December. The biodiversity, evenness and richness index in surveyed stations were 2.715-3.413 (H'), 0.758-0.851(E'), and 5.202-8.720 (R) respectively. The dominance index was the highest in station M2 and the lowest in station M1.

• Korean Journal of Environmental Biology
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• v.31 no.1
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• pp.37-44
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• 2013

This study was to investigate water quality and biotic community characteristics in Juam Lake. In water quality, water temperatures was $3.8{\sim}21.2^{\circ}C$, 6.7~8.6 in pH, $64{\sim}76{\mu}s\;cm^{-1}$ in Conductivity, $5.3{\sim}13.2mg\;L^{-1}$ in DO, $2.5{\sim}3.3mg\;L^{-1}$ in COD, $1.0{\sim}5.1mg\;L^{-1}$ in SS, $0.622{\sim}0.841mg\;L^{-1}$ in T-N, $0.007{\sim}0.019mg\;L^{-1}$ in T-P and $2.8{\sim}8.8mg\;m^{-3}$ in Chl-a. Revised Carlson's Index (TSIm) assessment using total phosphorus (TP) and chlorophyll-a domonstrated that the trophic states of Juam Lake were rated as mesotrophic. A total of 53 species of phytoplankton were identified. They were 28 Bacillariophyceae, 13 Chlorophyceae, 3 Cyanophyceae, and 9 Other algal taxa. The standing crops of phytoplankton was ranged from $113cells\;mL^{-1}$ to $2,909cells\;mL^{-1}$. A total of 16 species of zooplankton were identified (10 rotifers, 4 cladocerans and 2 copepods). Total zooplankton abundance was $309ind.\;L^{-1}$ to $435ind.\;L^{-1}$. The collected benthic macroinvertebrates from the surveyed sites in Juam Lake were 1,038 individuals, 33 species, 21 families and 12 orders. A dominant species was Uracanthella rufa and a subdominant species was Ecdyonurus kibunensis. Hydrophytes recorded from Juam Lake were identified 9 taxa. Emerged plants, floating plants among the hydrophytes was classified 8, 1 taxa, respectively. Ecosystem disturbance wildplant by Environment Ministry found were Paspalum distichum var. distichum and Ambrosia artemisiaefolia. A total of 30 species (6 families) were collected fishs from Juam Lake. There were 10 Korean endemic species (33.3% of collected species number) and 3 exotic species (10.0%).