• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1253-1258
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• 2012

In the present study, we investigated the effects of Rubus coreanus Miquel (RCM) on memory ability of senescence-accelerated mice (SAM). Prone 8 strains of SAM mice (SAMP8), which is a useful animal for investigating the mechanism of brain aging and senile dementia, were fed a diet containing 100 mg/kg body weight/day of RCM for 8 weeks. Memory ability of mice was examined by using passive avoidance test and Morris water maze test. SAMP8 mice showed remarkable memory impairment compared with senescence-resistant 1 strains of SAM (SAMR1). RCM significantly improved memory ability of SAMP8 mice. In addition, acetylcholineasterase activities decreased in the brain of SAMP8 mice treated with RCM. Taken together, these results suggest that RCM may act as an acetylcholineasterase inhibitor, thereby improving senescence-related memory impairment.

• Korean Journal of Remote Sensing
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• v.38 no.3
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• pp.237-250
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• 2022

In this study, we propose a method to estimate the biomass of invertebrate grazers from the videos with underwater drones by using a multi-object tracking model based on deep learning. In order to detect invertebrate grazers by classes, we used YOLOv5 (You Only Look Once version 5). For biomass estimation we used DeepSORT (Deep Simple Online and real-time tracking). The performance of each model was evaluated on a workstation with a GPU accelerator. YOLOv5 averaged 0.9 or more mean Average Precision (mAP), and we confirmed it shows about 59 fps at 4 k resolution when using YOLOv5s model and DeepSORT algorithm. Applying the proposed method in the field, there was a tendency to be overestimated by about 28%, but it was confirmed that the level of error was low compared to the biomass estimation using object detection model only. A follow-up study is needed to improve the accuracy for the cases where frame images go out of focus continuously or underwater drones turn rapidly. However,should these issues be improved, it can be utilized in the production of decision support data in the field of invertebrate grazers control and monitoring in the future.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.189-199
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• 2007

The present survey paper introduces the research history, characteristics of body and fin shapes, basic principles of various locomotions and propulsion-generation mechanism of aquatic animals in nature, which utilize unsteady flow through a noble mechanism that is different in paradigm from the propulsion generation mechanism of man-made marine vehicles, and so have excellent performance and efficiency. The authors hope that the present paper helps to activate the domestic research interest on the fields of swimming in nature, which is expected to provide great ideas for improvement and innovation of today's marine vehicles.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.21-22
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• 2000

생물의 특성 중 하나는 외부나 내부의 자극에 대하여 반응한다는 것이다. 이러한 환경의 변화를 감각기관에서 수용하여 그 환경의 변화에 적절하게 대응하는데 이러한 반응은 작게는 운동, 크게는 행동이라는 형태로 나타난다. 동물에 있어서 이와 같이 자극에 대하여 특이한 반응행동을 일으키는 성질들을 주성(Taxis)이라 한다. 주성에는 자극에 따라 주광성, 주촉성, 주류성, 주온성 등이 있으나 어업에 있어서 가장 광범위하게 이용하고 있는 것이 어류의 주광성이라 할 수 있다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.501-502
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• 2001

갯벌의 수질정화기능에 대하여 다양한 정의를 내릴 수 있으나 본 연구에서는 갯벌의 여과식성 저서생물에 의해 수중의 동ㆍ식물 플랑크톤과 데트리터스를 포함하는 입자성 유기물 (POM)이 포집되어 제거되는 기능으로 그 범위를 한정하였다. 갯벌생태계에서 수질정화기능의 핵심적 역할은 단연 이매패류가 담당하고 있다. 이들은 탁월한 여과능력으로 먹이 섭식과정에서 많은 양의 해수를 아가미로 걸러내기 때문에 결과적으로 수층의 입자성 유기물을 물리적으로 제거시키는 자연 여과시스템에 견주어진다. (중략)

• The Korean Journal of Soil Zoology
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• v.4 no.2
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• pp.61-68
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• 1999

This study reports evolution of spiders which were introduced 400 million years ago in ecological and evolutional aspects. First ecological aspects: underwater life, life of fallen leaves, the crevice of soil, underground life, life in cavern, wandering life in the surface of the earth and threading life in the air. Second evolutional aspects : a kind of the arachnids and morphological change.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.297-309
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• 2023

The degradation of coastal ecosystems and fishery environments is accelerating due to the recent phenomenon of invertebrate grazers. To effectively monitor and implement preventive measures for this phenomenon, the adoption of remote sensing-based monitoring technology for extensive maritime areas is imperative. In this study, we compared and analyzed the robustness of deep learning-based object detection modelsfor detecting and monitoring invertebrate grazersfrom underwater videos. We constructed an image dataset targeting seven representative species of invertebrate grazers in the coastal waters of South Korea and trained deep learning-based object detection models, You Only Look Once (YOLO)v7 and YOLOv8, using this dataset. We evaluated the detection performance and speed of a total of six YOLO models (YOLOv7, YOLOv7x, YOLOv8s, YOLOv8m, YOLOv8l, YOLOv8x) and conducted robustness evaluations considering various image distortions that may occur during underwater filming. The evaluation results showed that the YOLOv8 models demonstrated higher detection speed (approximately 71 to 141 FPS [frame per second]) compared to the number of parameters. In terms of detection performance, the YOLOv8 models (mean average precision [mAP] 0.848 to 0.882) exhibited better performance than the YOLOv7 models (mAP 0.847 to 0.850). Regarding model robustness, it was observed that the YOLOv7 models were more robust to shape distortions, while the YOLOv8 models were relatively more robust to color distortions. Therefore, considering that shape distortions occur less frequently in underwater video recordings while color distortions are more frequent in coastal areas, it can be concluded that utilizing YOLOv8 models is a valid choice for invertebrate grazer detection and monitoring in coastal waters.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.717-731
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• 2021

We analyzed the characteristics of the habitat environment for the Seonam study area in Ulsan, the southern shore of the East Sea using bathymetry and seafloor environment data. The depth of the study area ranges from about 0 m to 23 m. In the west of the study area, the water depth is shallow with a gentle slope, and the water depth becomes deeper with a steep slope in the east. Due to the right-lateral strike-slip faults located in the continental margin of the East Sea, the fracture surfaces of the seabed rocks are mainly in the N-S direction, which is similar to the direction of the strike faults. Three seafloor types (conglomeratic-grained sandy, coasre-graiend sandy, fine-grained sandy) and rocky bottom area have been classified according to the analyses of the bathymerty, seafloor image, and surface sediment data. The rocky bottom areas are mainly distributed around Seaoam and in the northern and southern coastal area. But the intermediate zone between Seonam and coastal area has no rocky bottom. This intermediate area is expected to have active sedimentation as seawater way. The sandy sediments are widely distributed throughout the study area. Underwater images and UAV images show that Cnidarians, Brachiopods, Mollusks are mostly dominant in the shallow habitat and various Nacellidae, Mytilidae live on the intertidal zone around Seonam. Annelida and Arthropod are dominant in the sandy sediments. The distribution of marine organism in the study area might be greatly influenced by the seafloor type, the composition and particle size distribution of the seafloor sediments. The analysis of habitat environment mapping with bathymetry, seafloor data and underwater images is supposed to contribute to the study of the structure and function of marine ecosystem.

• Journal of Navigation and Port Research
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• v.30 no.3 s.109
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• pp.241-245
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• 2006

Displayed result that handle particle contaminant and hydrospace organism included a number of ballast that is happened in ship using automatic back washing filter. Reason that removes first contaminant that is included in number of ballast is that heighten processing effectof after processing processof the filter. Another advantage is to drop off the solids with controlling revolution of drum screen in pretreatment filtration process. The fact that it is easy to attach and detach a several type of screen for getting the expected water quality is another advantage. Filter rotation speed of filtration filter could be expose by 35mmHg more than 60 rpm and filter consecutively filtration pressure is 40.5mmHg in 20 rpm and 40 rpm are 36.6mmHg. Filtration system removal aquatic organism over $70{\mu}min$ ballast water. This study shows that the filtration treatment system has a potential for the treatment of ballast water.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.181-185
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• 2005

The treated ballast water from previous treatment contains microorganisms and pathogenic organisms in an filtration treatment system. The advantage of this process can be filtrated to minimize the demage to screen clogging of drum filter with sweeping the solids off rotating the surface of the filter. Another advantage is to drop off the solids with controlling revolution of drum screen in pretreatment filtration process. Also the fact that it is easy to attach and detach a several type of screen for getting the expected water quality is another advantage, too. Filter rotation speed at 20rpmis 40.5cmHg and 40rpm is 36.6cmHg. Filter out impurities from ballast water over 60rpm is 35cmHg. Filtration system removal aquatic organism over $80{\mu}m$ in ballast water. This study shows that the filtration treatment system has a potential for the removal of ballast water.