• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.388-389
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• 2002

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.55-65
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• 2018

This study was conducted to clarify diet items and predatory behavior of American bullfrog (Lithobates catesbeianus) according to the sex, maturity and season from April to September 2014 at Gahang wetland of Changnyeong-gun, Gyeongsangnamdo province, Korea. We examined the stomach contents of L. catesbeianus using a gastrectomy technique and identified the contents to a genus or species. The examination showed that large and heavy individual of L. catesbeianus fed on larger amounts of food. However, there were no statistically significant differences in predation amount according to the sex and maturity of L. catesbeianus. The main diet item of during the study period was mostly Insecta (average population rate of 65.5%), followed by Crustacea (13.5%) and Gastropoda (7.9%). The most preferred diet item of L. catesbeianus was Muljarus japonicus. Surprisingly, L. catesbeianus also foraged Parus major, Apodemus agrarius, and Crocidura lasiura. Ths findings showed that L. catesbeianus directly disturbed the wetland ecosystem. We expect the results will be the important reference data for checking the impact of L. catesbeianus, which is designated as invasive species by the Ministry of Environment, on wetland ecosystem.

• 한국해양학회지
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• v.21 no.1
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• pp.25-33
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• 1986

Ontogenetic food habits of the four most abundant fish species in seagrass neadows of Redfish Bay, Texas, were examined quantitatively during 1982-1983. The darter goby (Gobionellus bolelsoma) and pinfish (Lagodon rhomboides) were trophic generalists, which used a wide range of food items. The darter goby had relatively diverse, omnivorous diet which included amphipods, copepods, polychaetes, filamentous algae, diatoms, and detritus. This species did not show distinct ontogenetic changes in foodpreferences. Unlike the darter goby, the pinfish showed ontogenetic progression of four feeding stages. An initial feeding stage was a planktivorous stage in which copepods were int major food items, followed by a carnivorous stage in which amphipods became the major food items, an omnivorous stage in which filamentous algae, diatoms, amphipods, and polychaetes were the major food items, and finally a herbivorous stage in which seagrass pieces with attached epiphytes and their debris were the major food items. The code goby (Gobiosoma robustrm) and Gulf pipefish (Syngathus scovelli) appeared to be relatively specialized in food havits as carnivorous. Similar ontogenetic changes in food habits were observed for these two species, i.e.initially, copepods were the major food items, followed by a gradual transition to amphipods with growth.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.319-327
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• 2000

The feeding behavior of 1-year-old silver carp, Hypophthalmichthys molitrix (Val.) on phytoplankton species in a shallow hypertrophic lake was studied from 22 May to 18 September, 1997. Over the experimental period, the filter-pore sizes of the fish, the total biomass of the phytoplankton and the water temperature in each enclosure changed little with time. The fish biomass in each enclosure increased with time, while their percentage of weight gain correlated negatively to the stocking density, due perhaps to competition for prey. An analysis of gut contents of silver carp showed a strong similarity between the algal communities in the foregut and the water, and was significant for the fish enclosure with a low density (p<0.05). The presence of silver carp rarely suppressed the abundance of phytoplankton such as Oscillatoria, Anabaena and Melosira even at high ingestion levels. There were weak relationships between the IU values of each phytoplankton and the selectivity of fish on them (r = 0.001, p>0.5). There was no doubt that the silver carp fed unselectively when cyanobacteria populations were high, even though the selectivity index for diatoms was slightly higher than those for cyanobacteria, green algae and cryptomonads. Improvements in methodologies are needed to clearly understand and generalize the feeding behavior of silver carp.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.418-421
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• 2003

This study is object to design and souctural analysis of duck breeding system. Design tool is Auto CAD and souctural analysis of duck breeding system using result from ANSYS Code. The finite element model was developed to compute the stress, strain and displacement for duck breeding system. This structural analysis results, many variables such as boundary condition, constraint condition and load condition are considered.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.358-367
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• 2010

Feeding habits of Acentrogobius pellidebilis collected from in an eelgrass(Zostera marina) bed from January to December 2006 were studied. A. pellidebilis ranged form 1.6 to 6.9 cm in standard length were determined. A. pellidebilis was a carnivore which consumed mainly copepods, polychaetes, and amphipods. Its diets included small quantities of isopods, seaweeds, nematods, and gastropods. It showed ontogenetic changes in feeding habits. Smaller individuals (<2.0cm SL) fed mainly on copepods. While the consumption of copepods decreased with increasing fish size, the consumption of polychaetes and amphipods were increased. Dietary breadth index was varied with fish size.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.489-490
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• 2001

해초가 밀생하기에 알맞은 연안 환경을 지닌 우리나라의 경우, 해초생태계에 관한 연구가 얼마 전까지만 해도 부진하였으나, 최근 들어 제주도와 광양만 잘피밭을 중심으로 활발히 연구가 진행되고 있다. 그 결과 해초의 형태 및 생활사 등에 관한 연구(Kong, 1981, 1982), 해초지 어류 군집에 관한 연구(Huh, 1986; Go and Cho, 1997a; Huh md Kwak, 1997d), 해초지에 서식하는 어류의 먹이습성에 관한 연구(Go et al., 1997b; Huh and Kwak,1997a, b, c,1998a, b, c, d, e, f), 저서생물에 관한 연구(Yun et al., 1997), 새우류에 관한 연구(Huh and An, 1997), 게류에 관한 연구(Huh and An, 1998), 부착해조류에 관한 연구(Huh et al., 1998) 등 다양한 연구 결과가 발표되고 있다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.221-222
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• 2000

수산환경에 있어 저질성상은 탁도, pH 및 영양염류 등과 같은 수질환경에 영향을 미치며, 새우류의 자연서식지 및 양식장에서는 이들의 분포 및 먹이활동에 영향을 미친다 (Ruello, 1973; Huguenin and Colt, 1989). 대하는 유생기의 발달단계가 진행됨에 따라 천천히 저질 속으로 잠복하기 시작하며, 치하 및 성체시기에는 주야간에 걸쳐 저질과 수중을 오가며 생활하는 습성을 가지고 있다. (중략)

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.865-873
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• 2016

Since 2004, Asiatic Black Bear of the Jirisan National Park is subjected to the restoration project through the re-introduction by the Maritime Province of Siberia in Russia, North Korea, Northeastern part of China and Seoul Grand Park. The purpose of this study is to analyze diets with scat to identify Asiatic Black Bear's feeding habit and eating resources environment in the Jirisan National Park. 78 scats of Asiatic Black Bears were observed during the field studies of radio telemetry-marked bears and by chance in the Jrisan National Park, from 2005 to 2013. The relative frequency of occurrence demonstrated that the plants comprised the highest with 77%, followed by insects with 12.8%, mammals with 5.6%, birds with 0.5%, arthropoda with 0.5%, and others with 3.6%. Also, 52 scats among the collected scats that were measured for the ratio of food were subjected to dry weight, and plants were the highest with 91.2%, followed by mammals with 3.6%, insects with 1.0% and others with 4.2% in the order mentioned. Asiatic Black Bear's feed research demonstrated that the Asiatic Black Bear at Jirisan is omnivorous and that the vegetable food is the main feed instead of animal feed.

• The KIPS Transactions:PartB
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• v.16B no.3
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• pp.195-202
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• 2009

In this paper, we propose the regions segmentation method of the white matter and the gray matter for brain MR image by using the ant colony optimization algorithm. Ant Colony Optimization (ACO) is a new meta heuristics algorithm to solve hard combinatorial optimization problem. This algorithm finds the expected pixel for image as the real ant finds the food from nest to food source. Then ants deposit pheromone on the pixels, and the pheromone will affect the motion of next ants. At each iteration step, ants will change their positions in the image according to the transition rule. Finally, we can obtain the segmentation results through analyzing the pheromone distribution in the image. We compared the proposed method with other threshold methods, viz. the Otsu' method, the genetic algorithm, the fuzzy method, and the original ant colony optimization algorithm. From comparison results, the proposed method is more exact than other threshold methods for the segmentation of specific region structures in MR brain image.