• 제어로봇시스템학회논문지
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• 제18권10호
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• pp.928-933
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• 2012

In this paper, the IR and compass sensors for the underwater system were used. The walls of the water tank have been recognized and avoided treating the walls as obstacles by the bio-mimetic underwater robot. This paper is consists of two parts: 1.The hardware part for the IR and compass sensors and 2.The software part for obstacle avoidance algorithm while the bio-mimetic robot is swimming with the obstacle recognition. Firstly, the hardware part controls through the RS-485 communications between a microcontroller and the bio-mimetic underwater robot. The software part is simulated for obstacle recognition and collision avoidance based upon the data from IR and compass sensors. Actually, the bio-mimetic underwater robot recognizes where is the obstacle as well as where is the bio-mimetic robot itself while it is moving in the water. While the underwater robot is moving at a constant speed recognizing the wall of water tank as an obstacle, an obstacle avoidance algorithm is applied for the wall following swimming based upon the IR and compass sensor data. As the results of this research, it is concluded that the bio-mimetic underwater robot can follow the wall of the water tank efficiently, while it is avoiding collision to the wall.

• The Plant Pathology Journal
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• 제35권5호
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• pp.417-424
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• 2019

Melanose, caused by Diaporthe citri, is one of severe diseases in citrus, a major economic resource in Jeju island. To reduce the usage amount of organic synthetic fungicide, bio-sulfur was tested as an alternative chemical to control citrus melanose in the present study. Direct antifungal activity of bio-sulfur against D. citri was determined through in vitro experiment using artificial nutrient media. Disease severity of melanose on bio-sulfur pretreated citrus leaves was lower than that on untreated ones. To illustrate the mechanism of disease suppression by bio-sulfur, infection structures were observed with a fluorescent microscope and a scanning electron microscope. In fluorescent microscopic observation, most conidia rarely germinated. In addition, hyphal growth on leaves pretreated with bio-sulfur was inhibited compared to that on untreated ones. In scanning electron microscope images of bio-sulfur pretreated leaves, surfaces of most conidia were shrunk while hyphae were morphologically changed and frequently branched. Such microscopic observations were also found for leaves pretreated with a commercial fungicide Dithianon. These results suggest that bio-sulfur may be used to control citrus melanose as an environment friendly alternative to organic synthetic fungicides

• Reproductive and Developmental Biology
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• 제29권2호
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• pp.93-99
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• 2005

Human embryonic stem cells (hESCs) derived from the inner cell mass of blastocysts have the ability to renew themselves and to differentiate into cell types of all lineage. The present study was carried out to investigate whether the Wnt signaling pathway is related to maintaining self-renewal of hESCs. Glycogen Synthase Kinase 3 (GSK-3) inhibitor, BIO ((2'Z,3'E)-6-Bromoindirubin-3'-oxime) was treated to Miz-hES1 line for activation of Wnt signaling pathway. BIO-nontreated hESCs (control) and BID-treated hESCs were cultured for 5 days in the modified feeder-free system. During the culture of hESCs, differences were observed in the colony morphology between 2 groups. Controls were spread outwards whereas BIO-nontreated hESCs were clumped in the center and the differentiated cells were spreading outwards in the edges. The results of stem cell specific marker staining indicated that control were differentiated in large part whereas BIO-treated hESCs maintain self-renewal in the center of the colony. The results of lineage marker staining suggested that outer cells of the hESC colony were differentiated to the neuronal progenitor cells in both control and BIO-treated hESC. These results indicate that Wnt signaling is related to self-renewal in hESCs. In addition, control group showed higher composition of apoptotic cells $(23.76\%)$ than the BID-treated group $(5.59\%)$. These results indicate that BIO is effective on antapoptosis of hESCs.

• 생물환경조절학회지
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• 제19권4호
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• pp.183-188
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• 2010

본 연구는 딸기의 수경재배에서 증발냉각방식을 이용하여 배지의 지하부 온도를 관리할 수 있는 냉각시스템을 개발하고 고온기 온실내 기온에 따른 배지내 온도분포 특성을 분석하고자 다공질 필름 덕트법, 배지 상면 기습부직포 멀칭법, 투수부직포 재배조 표면 증발법의 3가지 냉각시스템에 대하여 배지냉각특성을 시험하였다. 그 결과 투수부직포 재배조 표면 증발법의 경우 온실내 기온 $35^{\circ}C$인 배지표면의 온도와 상대습도 50%일 때 재배조 표변의 부직포의 온도는 $27^{\circ}C$로 니타났으며, 뿌리가 많이 분포되어 있는 배지내 온도는 $28{\sim}30^{\circ}C$ 정도로 나타나 외기온에 비하여 $5{\sim}7^{\circ}C$ 정도로 기장 크게 강하되었다. 따라서, 투수부직포 재배조 표면 증발법이 가장 효율적인 배지냉각 방법이라고 판단된다.

• 한국유기농업학회지
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• 제28권2호
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• pp.223-233
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• 2020

본 연구에서는 친환경 농가에서 사용되고 있는 바이오 황(Bio-S, bio-sulfur)을 이용하여 감귤 더덩이병(Citrus scab)에 대한 발병 억제 효과를 알아보고자 수행되었다. 바이오 황이 감귤 더뎅이병의 발아관 생장 억제 효과는 감귤 더뎅이병균을 PDB와 Agar 배지에서 배양하여 발아관을 관찰한 결과 접종 40시간과 88시간 모두 바이오 황 500배, 1,000배, 2,000배 처리구에서 발아관 형성이 억제되었으며, 4,000배 이상 희석배수가 높아질수록 발아관은 형성되었으나 무처리구에 비해 생장이 억제되었다. 포장에서 감귤 봄순 잎에 대한 더뎅이병의 발병 억제 효과는 무처리구 이병율은 40.3%였으며, 화학농약인 Imibenconazole 수화제 이병율이 5.3%을 보였으며, 친환경 농업에 사용하는 석회보르도액 2-4식과 6-6식은 모두 10.3%, 바이오 황 500배 12.3%, 석회유황합제 15.3%로 비슷한 경향을 나타냈으며, 반면 바이오 황 1,000배에서는 24.0%로 비교적 높은 이병율을 보였다. 감귤 과실에 대한 시험결과 무처리구 이병율은 79.3%였으며, Imibenconazole 수화제 이병율은 4.0%을 보였으며, 석회보르도액 2-4식 33.8%, 6-6식 42.0%, 바이오 황 500배 43.3%, 석회유황합제 44.8%로 비슷한 효과를 나타냈으며, 반면 바이오 황 1,000배에서는 78.0%로 비교적 높은 이병율을 보였다. 따라서 감귤 더뎅이병은 봄순이 전개되는 5월부터 감귤의 잎에 발생하기 때문에 봄순이 전개되기 전인 4월 중하순부터 예방방제를 시작하여 예찰을 통해 방제하면 높은 방제율과 노동력 및 영농비용 등을 절감할 수 있을 것으로 생각된다.

• 농약과학회지
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• 제13권4호
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• pp.325-331
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• 2009

세 종류의 유용세균, Lactobacillus KLF01, Lactococcus KLC02 그리고 Paenibacillus KPB3는 무름병원세균 Pectobacterium carotovorum subsp. carotovorum (Pcc)에 대한 기내 길항효과를 나타내었으며, 온실 내 포트에서 배추 무름병에 대한 생물적 방제 효과를 병원균 접종 4, 8, 12일 후 각각 조사한 결과 KLC02 균주는 64%, 50%, 56%, KPB3 균주는 66%, 57%, 58%로 나타났다. 반면, KLF01 균주는 KLC02 및 KPB3 균주에 비해 그 효과가 다소 낮았으나 유의성이 인정될 수 있는 방제효과로 조사되었다. 또한 재배포장에서 배추 무름병에 대한 생물적 방제효과는 KLF01, KLC02 및 KPB3 모두 각각 55%, 60% 그리고 62%로 매우 효과적임을 알 수 있었다. 따라서 세 종류의 유용세균 Lactobacillus KLF01, Lactococcus KLC02 그리고 Paenibacillus KPB3 균주를 이용하여 배추 무름병을 억제하기 위한 생물적 방제제로 활용할 수 있음을 보고한다.

• 한국수산과학회지
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• 제48권5호
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• pp.688-695
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• 2015

The objective of this study was to investigate the effects of bio-floc system that is composed of effective microorganisms (EM) on the microbial composition and water qualities in rearing water and the growth of Chinese white shrimp, Fenneropenaeus chinensis. To investigate the microbial composition according to the bio-floc levels, the study was conducted at 100 and 150% of bio-floc after 5 and 10 days in bio-floc system. The results showed that total bacteria count (TBC) and the counts of Latobacillus sp., Bacillus sp. and Rhodobactor sp., were significantly decreased after 5 days in bio-floc system. To assess the growth of F. chinensis according to the concentrations of bio-floc, the study was conducted at the bio-floc concentrations; 0 (control), 60, 80, 100, 120 and 140% of the prepared bio-floc for 90 days. The growth factors such as daily length and weight gain were considerably increased at the concentrations of bio-floc 100, 120, and 140% after 90 days. As water quality indicators, the values of total-N, NH₄⁺-N and PO₄^--P were analyzed, and they were significantly decreased at 120 and 140% of bio-floc, compared to the control. The results demonstrated that combination of EM showed the synergic effect on removing N and P.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권3호
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• pp.282-293
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• 2018

This paper attempts to address the motion parameter skip problem associated with three-dimensional trajectory tracking of an underactuated Autonomous Underwater Vehicle (AUV) using backstepping-based control, due to the unsmoothness of tracking trajectory. Through kinematics concepts, a three-dimensional dynamic velocity regulation controller is derived. This controller makes use of the surge and angular velocity errors with bio-inspired models and backstepping techniques. It overcomes the frequently occurring problem of parameter skip at inflection point existing in backstepping tracking control method and increases system robustness. Moreover, the proposed method can effectively avoid the singularity problem in backstepping control of virtual velocity error. The control system is proved to be uniformly ultimately bounded using Lyapunov stability theory. Simulation results illustrate the effectiveness and efficiency of the developed controller, which can realize accurate three-dimensional trajectory tracking for an underactuated AUV with constant external disturbances.

• 로봇학회논문지
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• 제14권4호
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• pp.264-269
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• 2019

This paper presents mechanical design and control of a bio-inspired legged robot. To achieve a fast legged running mechanism, a novel linkage leg structure is designed based on hind legs of domestic cats. The skeletomuscular system and parallel leg movement of a cat are analyzed and applied to determine the link parameters. The hierarchical control architecture is designed according to the biological data to generate and modulate desired gaits. The effectiveness of the leg mechanism design and control is verified experimentally. The legged robot runs at a speed of 46 km/h, which is comparatively higher speed than other existing legged robots.

• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 2006년도 춘계 학술대회 및 정기총회
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• pp.108-112
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• 2006