• 반도체디스플레이기술학회지
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• 제9권3호
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• pp.17-21
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• 2010

As the compact and easily accessible handheld devices, such as cellular phones and MP3 players equipped with image acquisition functionality, are becoming widely available among common users, various applications of images are rapidly increasing. Image related services and software such as web-based image presentation and image manipulation for personal or commercial purpose enable users to view contents of remote image archive and to manipulate enormous amount of images in local or network based storage as well. It is necessary for users to identify the images efficiently so that the same images are perceived as one physical entity instead of recognizing them as different images as the trends are getting stronger. In order to support this environment, we propose a method that generates image identifiers or indexing for images within a solid and efficient manner. The proposed image identifier utilizes multiple index values. The integration of component index values creates a unique composite value that can be used as a file name, file system identifier, or database index. Our experimental results on generation of constituent index values have shown favorable results.

• 한국컴퓨터정보학회논문지
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• 제23권9호
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• pp.35-42
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• 2018

In this paper, we propose an optimal streaming service method based on Hybrid CDN/P2P architecture. Recently, video streaming utilizes a CDN (Content Delivery Network) operation technique based on a Proxy Server, which is an end node located close to a user. However, since CDN has a fixed network traffic bandwidth and data information exchange among CDNs in the network is not smooth, it is difficult to guarantee traffic congestion and quality of image service. In the hybrid CDN/P2P network, a data selection technique is used to select only the data that is expected to be continuously requested among all the data in order to guarantee the QoS of the user who utilizes the limited bandwidth efficiently. In order to search user requested data, this technique effectively retrieves the storage information of the constituent nodes of CDN and P2P, and stores the new image information and calculates the deletion priority based on the request possibility as needed. Therefore, the streaming service scheme proposed in this paper can effectively improve the quality of the video streaming service on the network.

• 한국지반공학회논문집
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• 제26권5호
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• pp.27-36
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• 2010

본 연구에서는 동상성이 높은 대상 시료에 입경이 다른 3종의 폐타이어분말을 대상으로 서멀 프루브법을 이용하여 $-20^{\circ}C{\sim}+10^{\circ}C$의 온도변화에 따른 열전도율을 실측하는 것과 동시에 펄스형NMR장치를 이용하여 동토중의 부동수분량을 측정하였고 이를 온도함수로 나타내었다. 또한 열전도율 계산모델의 하나인 2상계모델을 발전시켜 3상계 동결토영역에 적용 가능한 새로운 모델을 제안하였다.

• 한국수산과학회지
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• 제57권2호
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• pp.137-144
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• 2024

In this study, we investigated the antioxidant and physiological activities of the Korean marine algae, Enteromorpha compressa. Solvent extracts of E. compressa were prepared using 70% ethanol, 80% methanol, and water, with extraction yields ranging from 9.55% to 25.67%. The total polyphenol and flavonoid contents ranged from 20.76-28.41 mg/g and 2.56-18.59 mg/g, respectively. Compared with the water extract, the ethanol and methanol extracts were found to have higher antioxidant activities. All three extracts were found to promote alcohol dehydrogenase and aldehyde dehydrogenase activities in a concentration-dependent manner, whereas the methanol and ethanol extracts were established to have the highest angiotensin-converting enzyme (ACE) inhibitory activity (IC₅₀=1.40 ㎍/mL) and β-secretase inhibitory activity (IC₅₀=0.17 ㎍/mL), respectively. These findings thus indicate that E. compressa could have beneficial application as a supplementary antioxidant and functional constituent in food and pharmaceutical materials.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1091-1099
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• 2024

Fluoride-salt-cooled High-temperature Reactor (FHR) is a promising nuclear reactor technology. Among many challenges presented by the molten fluoride salts is the corrosion of salt-facing structural components. Higher moisture contents, in the FLiNaK (LiF-NaF-KF, 46.5-11.5-42 mol%) salt, aggravate intergranular corrosion and pitting for the given alloys. Therefore, several thermal dehydration tests of FLiNaK salt were performed with a batch size suitable for thermal-hydraulic experiments. Thermogravimetric Analysis (TGA) was performed for the three constituent fluoride salts individually. Preliminary thermal dehydration plans were then proposed for NaF and KF salts based on the TGA curves. However, the dehydration process may not be required for LiF since its low mass loss (<1.3 wt%). To evaluate the performance of these thermal dehydration plans, a batch-scale salt dehydration test facility was designed and constructed. The preliminary thermal dehydration plans were tested by varying the heating rates, target temperature, and holding time. The sample mass loss data showed that the high temperatures (>500 ℃) were necessary to remove a significant amount of moisture (>1 wt%) from NaF salt, while relatively low temperatures (around 300 ℃) with a long holding time (>10 h) were sufficient to remove most of the moisture from KF salt.

• 한국자원식물학회지
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• 제26권6호
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• pp.663-672
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• 2013

To characterize the nutraceutical property of Italian millet (Setaria italica) and sorghum (Sorghum bicolor), ten Korean landraces of each crop were collected and their vitamin E (tocopherols and tocotrienols), squalene and phytosterols (campesterol, stigmasterol and ${\beta}$-sitosterol) contents as well as fatty acid composition in seeds were evaluated. Italian millet seeds exhibited 5 forms of vitamin E isomers: three (${\alpha}$-, ${\gamma}$- and ${\delta}$-) tocopherols and two (${\alpha}$- and ${\gamma}$-) tocotrienols, while sorghum seeds showed only three forms of vitamin E isomers: ${\alpha}$- and ${\gamma}$-tocopherol and ${\alpha}$-tocotrienol. In both crops, ${\gamma}$-tocopherol was the major constituent of vitamin E in terms of highest quantity. Total vitamin E content in Italian millet and sorghum landraces were 88.3 mg/kg and 44.3 mg/kg, respectively. Among three phytosterols (campesterol, stigmasterol and ${\beta}$-sitosterol) analyzed, ${\beta}$-sitosterol was the major form comprising about 85% and 65% in Italian millet and sorghum landraces, respectively. Total phytosterols content ranged from 443.0 to 568.5 mg/kg and 442.3 to 719.2 mg/kg in Italian millet and sorghum, respectively. Squalene, a precursor of phytosterols biosynthesis, ranged from 6.8 to 10.2 mg/kg in Italian millet and from 62.2 to 115.2 mg/kg in sorghum. Linoleic, oleic and palmitic acids were the major fatty acids in both of the crops and about 80% of the total fatty acids were unsaturated fatty acids. Among the tested landraces, M09 and S10 showed relatively higher proportion of phytonutrients, suggesting their potential as a gene source for further breeding program.

• 한국패류학회지
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• 제32권3호
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• pp.165-174
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• 2016

바지락의 섭식 특성을 분석하기 위해 서해의 곰소만에서 바지락의 소화관 내용물과 표층 해수의 식물플랑크톤 군집에 대해 정량 및 정성분석을 실시하였다. 바지락의 소화관에는 규조류 (71.5%), 와편모류 (13.1%), 미소플랑크톤 (6.6%) 과 중형동물플랑크톤을 포함한 유기쇄설물 등이 관찰되었다. 소화관내에서 섭식량은 겨울과 봄에 많았고 여름과 가을에 낮게 나타난 반면, 표층 해수의 식물플랑크톤 현존량은 가을에 가장 많았다. 또한 바지락의 크기가 클수록 섭식한 먹이생물의 양은 증가하였다. 소화관에서 관찰된 우점종은 저서성 규조류인 Paralia sulcata 및 Navicula arenaria와 와편모류의 cyst 이었던 반면 표층해수에서 우점종은 부유성 규조류인 Chaetoceros 속, Skeletonema 속, Asterionellopsis 속 등과 cryptomonads 및 P. sulcata이었다. 소화관 내용물 분석을 통해 바지락의 주요 먹이원은 저서성 규조류이며, 식물플랑크톤의 크기와 모양에 따라 선택적으로 섭식함을 확인하였다.

• 한국콘텐츠학회논문지
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• 제20권6호
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• pp.510-520
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• 2020

최근 들어 웹툰(Webtoon)은 인터넷 세대에게 선풍적인 인기몰이를 하고 있다. 실제 웹툰을 게임, 영화, 드라마 등으로 제작하여 세계적으로 인정을 받으며, 한류문화의 대표적 콘텐츠로 떠오르는 추세다. 이에 따라 사회각계에서 웹툰에 대한 관심이 집중되고 있다. 이러한 시대적 조류에 맞추어 본 연구는 엔터테인먼트로서 웹툰의 다른 이면인 교육적 활용가능성에 대해 탐구하고자 한다. 웹툰은 교육환경에서 매우 유용한 교육적 요소가 있다. 먼저 인터넷 세대인 학습자에게 매우 인기 있는 콘텐츠이며, 텍스트 위주의 수업환경에서 학습자에게 몰입감과 재미를 줄 수 있을 뿐 아니라, 웹툰이 지닌 서사성 및 맥락성은 교과와 연계하여 풍부한 자료를 제공할 수 있겠다. 본 연구는 웹툰의 교육적 활용가능성을 탐구하기 위하여 이론적, 실천적 방법으로 접근하고자 한다. 이를 위해 먼저 웹툰의 '교육적 활용요소'에 대한 이론적 근거를 탐색할 것이며, 예비교사들 즉, 인터넷 세대라 할 수 있는 예비교사 108명에게서 웹툰의 '교육적 활용가치'에 대한 의견을 수렴하고자 한다. 이후 예비교사들이 실제 웹툰 기반 수업설계를 시도하여 실천적으로 그 가능성을 탐색하였다. 본 연구를 통해 웹툰의 교육적 활용가능성에 대한 긍정적인 전망을 가늠해보고자 한다.

• 디지털콘텐츠학회 논문지
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• 제17권6호
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• pp.489-497
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• 2016

본 연구는 행위자의 행동을 유도하는 특성을 뜻하는 어포던스 관점으로 학습자의 안전행동을 증진시키는 안전교육 앱의 설계원리를 구체적으로 제시하는데 목적이 있으며, 설문조사를 기반으로 한 포커스 그룹 인터뷰를 중심으로 진행하였다. 안전교육 앱의 표현상의 특성인 어포던스를 측정하기 위하여 인지적 어포던스, 감각적 어포던스, 물리적 어포던스, 안전행동 증진에 관한 문항을 구성요인으로 사용하여 측정문항을 구성하였으며, 분석하고자 한 안전교육 앱은 소방방재청에서 개발한 '물놀이GO!' 앱을 선정하였다. 연구 결과 첫째, 학습자가 안전교육 앱 학습환경에서 유의미한 학습활동을 하게 하려면 지속적으로 학습에 참여하도록 도와야 한다. 둘째, 앱에서 모바일 기기와 상호작용 하면서 학습을 촉진하면서도 학습자의 학습을 방해할 수 있는 요소들은 줄여야 한다. 본 연구를 통해 안전교육 앱 학습환경을 구성할 때 안전행동을 증진시키는 가이드라인으로써 본 설계원리를 활용할 수 있다.

• The Korean Journal of Ecology
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• 제16권2호
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• pp.159-168
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• 1993

The seasonal changes of symbiotic nitrogen-fixation activity and environmental factors of autumn olive plant (Elaeagnus umbellata Thunb.), which is an important constituent species of temperate vegetation and a non-leguminous root nodule plant interacting with Frankia sp., were quantitatively analyzed inthe natural vegetations during hegrowing period. The acetylene redution April and showed two peaks of 133 and $145{\mu}M\;C_2H_4\;{\cdot}\;gfw^{-1}\;{\cdot}\;hr^{-1}$ in early June and mid September. The nitrogenase activity decreased to 10~30% during hot dry summer frommid June to the end of August, and disappeared during the dormant period of winter. The optimum rhizoshere. diurnal change showed the maximum activity in the mid-day and the minimum in the mid-night. The average contents of total nitrogen in each organ changed in the ranges of 42.5~40.1, 40.2~36.3, 30.3~28.6 and 18.4~16.2mgN $gdw^{-1}$ for nodule, leaf, root, and stem, respectively. The soil conditions of rhizosphere were weak acidic, ad seasonal variations of $NO_3^--N,\;NH_4^+-N,\;PO_4^{3-}-P$ and water contents were in the ranges of 48.3~79.5ppm,5.1~13.9ppm, 4.4~$9.9{\mu}M$ and 14.5~39.4%, respectively.