• 한국융합학회논문지
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• 제8권8호
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• pp.185-190
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• 2017

자연현상에서 발견되는 프랙털 (fractal) 구조는 자기 유사성 (self-similarity)의 반복된 형태로, 생명체의 발생과 기관 형성에서도 자주 관찰된다. 특히, 수많은 종류의 암모나이트에서 관찰되는 봉합선 (suture)의 복잡, 다양한 형태는 프랙털 생성에 대한 생물학적인 이해를 위한 좋은 연구소재이다. 본 연구에서는 희귀하게 초기 발생단계의 봉합선 구조가 매우 잘 보전된 Eogaudryceras sp.를 대상으로 봉합선 형성의 과정을 분석하고자 하였으며, 일반적으로 구하기 힘든 부위인 나선 (spiral) 중심부 1mm 이내의 현미경적인 관찰을 실시하였다. 아직 봉합선의 프랙털 구조 생성에 대한 생물학적인 기전은 아직 불분명한 상태이나, 본 연구를 통하여 암모나이트 발생초기에 프랙털 구조의 복잡성이 단계별로 분명한 차이가 있음을 발견하였다. 이러한 결과는 하나의 생명체 내에서 "Evo-Devo"의 여러 발생단계의 변화를 동시에 보여줄 수 있는 좋은 예시로서, 향후 프랙털 구조의 생물학적인 기전 연구 및 관련되는 다양한 융합학문에서의 접목과 활용이 기대된다.

• 한국강구조학회 논문집
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• 제25권6호
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• pp.613-622
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• 2013

우리나라의 지형 특성상 많은 중소하천들이 생성되어 있으며, 이에 대한 치수 목적으로 다양한 보가 건설되고 있다. 그 중 가동보는 고정보에 비해 저수위를 자유롭게 조절할 수 있고, 상류부 저층수의 수질악화, 수변 생물 서식처의 변화 등 고정보의 문제점을 개선할 수 있기 때문에 그 적용빈도가 증가하고 있는 추세이다. 이 연구에서는 가동보의 종류 중 하나인 다단전도방식 가동보에 대한 특징을 조사하고, 시공된 구조물을 예로 구조적 성능을 확인하기 위한 해석적 연구를 수행하였다. 또한, 유한요소해석을 통해 얻은 결과로부터 다단전도방식 가동보의 우수한 구조적 성능을 확인할 수 있었다.

• 수산해양기술연구
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• 제47권4호
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• pp.300-315
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• 2011

The investigation for the catch and species composition in the deep sea of the East Sea was done to search marine organisms using some kinds of traps with small commercial fishing vessel near Goseong, Korea from 2008 to 2009. The experiments was carried out with some different traps at the depth of 200m, 400m, 700m and 1,000m. In 2008, the amount of catch with rectangular, cone and drum net traps was 91.4kg with twelve trips and the proportion of catch with rectangular and cone traps was high. Dominant species caught were Aniwan whelk (57%), snow crab (12%), hunchback sculpin (7%) and red snow crab (5%). The catch of Aniwan whelk was done well with rectangular and cone traps at the depth of 700-1,000m. Snow crab was mainly caught with rectangular and cone traps at the shallower depth of 200m, while red snow crab caught a lot with cone trap at the deeper depth of 700m. In 2009, the amount of catch with rectangular, cone and round traps was 92.4kg with nine trips. The proportion of catch with round trap was higher than that with cone trap. Dominant species caught were snow crab (67.1%), Aniwan whelk (14.8%) and northern shrimp (9.8%). Snow crab was caught well with round trap at the depth less than 400m.

• Ocean and Polar Research
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• 제25권1호
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• pp.21-30
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• 2003

Seasonal fluctuations of physico-chemical and biological aspects of the environment were studied in Vladivostok harbour (Golden Horn Bay, the East Sea/Sea of Japan). The benthic community structure was described with a focus on size-spectra (bacteria, meio- and macrofauna) related with the chemical environment and chemical fluxes in sediment and to reveal their possible ecological role in the process of bioremediation of the environment. Samples from two sites with different concentrations of heavy metals (Fe, Zn, Cu, Pb, Mn, Cr, Ni Cd, Co) and petroleum hydrocarbon were assessed by a number of methods. These included plate counts of culturable bacteria, observation through a scanning electron (SEM) and transmission electron microscope (TEM). These approaches were complemented with microscopic assessments of the diversity of the benthic community. The specific communities had a limited number of species, tolerant to abnormally high levels of toxic compounds. The dominant species were presented by several sho.1-lived small polychaetes (Capitella capitata) and nematodes (Oncholaimium ramosum). The highest population density was recorded in microbenthos, in various diatoms, various physiological groups of bacteria which participate in biomineralization: marine heterotrophic bacteria, which oxidized oil, black oil in addition to groups resistant to heavy metals. They have the entire set of mechanisms for neutralizing the negative effect of those compounds, forming the detrital food web and biogeochemical circulation of material in sediments, which results in the biological self-recycling of sea basins. Macro- and meiobenthic organisms were more sensitive to a greater extent of $H_2S$ and petroleum hydrocarbons than to metal content, but the within-site rankings were the same as those achieved for microbiological analyses.

• 한국수산과학회지
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• 제31권3호
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• pp.372-379
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• 1998

1994년 1월부터 1994년 12월까지 광양만 대도주변 잘 피밭에서 채집된 날개망둑의 식성을 조사하였다. 날개망둑의 주요 먹이생물은 단각류 (특히 옆새우류), 갯지렁이류, 게류 및 요각류였으며, 그 외, 복족류, 이매패류, 주걱벌레붙이류, 등각류 등이 소량씩 위내용물 중에서 발견되었다. 날개망둑이 성장함에 따라 먹이생물의 조성이 점차 변하였다. 체장이 작은 날개망둑은 옆새우류, 갯지렁이류 및 요각류를 비교적 고르게 먹었으나, 체장이 증가하면서 요각류를 먹는 비율은 점차 낮아진 반면, 갯지렁이류. 게류를 먹는 비율은 증가하였다. 한편 옆새우류는 조사된 모든 크기에 걸쳐 가장 선호된 먹이생물이었다. 계절에 관계없이 옆새우류, 갯지렁이류, 게류 및 요각류가 주요 먹이생물이였으나, 봄과 가을에는 요각류가 차지하는 비율이 다른 계절에 비해 높았으며, 여름에는 옆새우류, 갯지렁이류 및 게류가 차지하는 비율이 다른 계절에 비해 높았다.

• Journal of Multimedia Information System
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• 제5권3호
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• pp.163-170
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• 2018

We developed a multicast communication packet radio protocol using a time-sharing tablet system ("wireless token ring") to achieve the efficient exchange of files among packet radio terminals attached to swans. This paper provides an overview of the system and the protocol of the packet communications. The packet device forming the main part of the transceiver developed is the Texas Instruments CC2500. This device consists of one call-up channel and one data transmission channel and could improve error frame correction using FEC (forward error correction) with 34.8 kbps MSK and receiving power of at least -64 dBm (output 1 dBm at distance of 200 m using 3 dBi antenna). A time-sharing framework was determined for the wireless token ring using call sign ordinals to prevent transmission right loss. Tests using eight stations showed that resend requests with the ARQ (automatic repeat request) system are more frequent for a receiving power supply of -62 dBm or less. A wireless token ring system with fixed transmission times is more effective. This communication protocol is useful in cases in which frequency resources are limited; the energy consumed is not dependent on the transmission environment (preset transmission times); multiple terminals are concentrated in a small area; and information (position data and vital data) is shared among terminals under circumstances in which direct communication between a terminal and the center is not possible. The method allows epidemiological predictions of avian influenza infection routes based on vital data and relationships among individual birds based on the network topology recorded by individual terminals. This communication protocol is also expected to have applications in the formation of multiple in vivo micromachines or terminals that are inserted into living organisms.

• Weed & Turfgrass Science
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• 제6권1호
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• pp.1-10
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• 2017

생물제초제의 이용은 농업에서 지속성을 향한 중요한 단계로 활용 될 수 있을 것이다. 유기농업 및 종합잡초관리는 보존농업에서 합성제초제와는 다르게 한 종류의 잡초관리기술에 의존하지 않아야 하며, 생물제초제는 다른 잡초관리기술과 동시에 평가되는 것이 바람직할 것이다. 우리나라 실정에 적합한 세균 및 진균으로부터 유래한 상업용 생물제초제를 선발하여 유기농업 농가에서 영농부가가치가 높은 고소득 작물을 대상으로 생물제초제 실용화 가능성을 검토할 가치가 있을 것이다. 또한 유기영농 과수원에서 비선택적으로 잡초를 방제하기 위하여 상업용으로 시판되는 옥수수 글루텐 가루 제제와 각종 식물정유 제제 등 제품에 대한 실용화 연구가 필요할 것이다.

• Genomics & Informatics
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• 제3권1호
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• pp.15-23
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• 2005

Background MicroRNAs (miRNAs) are a class of noncoding RNAs found in various organisms such as plants and mammals. However, most of the mRNAs regulated by miRNAs are unknown. Furthermore, miRNA targets in genomes cannot be identified by standard sequence comparison since their complementarity to the target sequence is imperfect in general. In this paper, we propose a kernel-based method for the efficient prediction of miRNA targets. To help in distinguishing the false positives from potentially valid targets, we elucidate the features common in experimentally confirmed targets. Results The performance of our prediction method was evaluated by five-fold cross-validation. Our method showed 0.64 and 0.98 in sensitivity and in specificity, respectively. Also, the proposed method reduced the number of false positives by half compared with TargetScan. We investigated the effect of feature sets on the classification of miRNA targets. Finally, we predicted miRNA targets for several miRNAs in the Caenorhabditis elegans (C. elegans) 3' untranslated region (3' UTR) database. Condusions The targets predicted by the suggested method will help in validating more miRNA targets and ultimately in revealing the role of small RNAs in the regulation of genomes. Our algorithm for miRNA target site detection will be able to be improved by additional experimental­knowledge. Also, the increase of the number of confirmed targets is expected to reveal general structural features that can be used to improve their detection.

• BMB Reports
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• 제47권11호
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• pp.625-630
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• 2014

Defensins, which are small cationic molecules produced by organisms as part of their innate immune response, share a common structural scaffold that is stabilized by three disulfide bridges. Coprisin is a 43-amino acid defensin-like peptide from Copris tripartitus. Here, we report the intramolecular disulfide connectivity of cysteine-rich coprisin, and show that it is the same as in other insect defensins. The disulfide bond pairings of coprisin were determined by combining the enzymatic cleavage and mass analysis. We found that the loss of any single disulfide bond in coprisin eliminated all antibacterial, but not antifungal, activity. Circular dichroism (CD) analysis showed that two disulfide bonds, Cys20-Cys39 and Cys24-Cys41, stabilize coprisin's ${\alpha}$-helical region. Moreover, a BLAST search against UniProtKB database revealed that coprisin's ${\alpha}$-helical region is highly homologous to those of other insect defensins.

• Ocean and Polar Research
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• 제35권4호
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• pp.323-349
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• 2013

The mud shrimp Upogebia major (Upogebiidae: Decapoda: Crustacea) is a common species on muddy and sandy mud tidal flats in the west coast of Korea. They reside in Y-shaped burrows that can extend up to more than 2 meters below the sediment surface. They feed on suspended detritus carried into their burrow by the beating of their pleopods and captured by their hairy first two pairs of thoracic legs. Mud shrimp burrows provide a habitat for a variety of small organisms such as crabs, shrimps, polychaetes, and mollusks. Ovigerous females are observed from December to May. Females deposit eggs only once per breeding season. They start hatching in March and the pelagic larvae of first zoea appear in March and April, followed by benthic settlement in May. Growth over the first year is rapid, and females deposit their first eggs in the third breeding season, 31 months after their settlement. Adult shrimps live for 4~5 years. Depth of the burrow increases with body length. The deep burrows provide refuge from predators and physical stress, allowing the shrimps to survive for a long time. The mud shrimps supply oxygen-rich water to their deep burrows, and exert a great influence on the structure and metabolism of the tidal flat benthic community. However, recently this type of mud shrimp has posed a serious threat to the Korean clam industry along the west coast of Korea. The extensive burrowing shrimp populations suddenly invaded the tidal flats from 2010 where the clams (Ruditapes philippinarum) are raised. As a consequence, clam production has decreased by about 10% over the past three years in some Korean clam beds. Therefore, the objective of this study is to review the biology of this mud shrimp in order to seek solutions to control the burrowing of these shrimps.