• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.117-120
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• 2008

As we can see at the oil spill occident on the coast of Taean, the viscosity of the spilled oil becomes thicker as time goes by. It becomes waste oil with the form of tar. It moves to other areas following a tide. When the temperature of the water goes up, the viscosity becomes lighter and forms oil film. It repeats the process spreading to and polluting extensive areas where the tide reaches. People have used hand nets to collect waste oil of tar at the sea. But it is very difficult for them to collect the tar type waste oil spread on large areas before it reaches to the beach. This paper tried to find a way to collect the tar type waste oil efficiently. It used absorption mat of boom type that uses the attachment characteristics of the tar type waste oil and floating waste recovery device of net type. It tested the possibility of using the devices at the oil spill accident on the beach of Taean. The result showed that net type recovery device was much more efficient in collecting the waste oil in short time than the hand net system of people. It confirmed that the net type recovery device could be used to collect tar type waste oil.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.451-458
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• 2018

The coast of Incheon reaches Incheon itself, Gimpo, Siheung, and Ansan of Gyunggi-do. Because this area has been seriously polluted, the Ministry of Oceans and Fisheries has established the Incheon Special Area Management Plan (SAMP) to preserve sea water quality as a marine environment asset. However, there is concern that actions taken in this area may change the surrounding marine ecology, being effected by farms, via a river that flows from waste lands, abandoned fishing activities and fishing nets, etc. Given this background, this study estimates the value of SAMP sea water quality using a choice experiment (CE). A CE survey of 1,000 households was undertaken, investigating trade-offs involving price and four attributes for selecting a preferred alternative to obtain a marginal willingness to pay (MWTP) estimate for each attribute. The estimation results showed that MWTP for a 1 %p improvement in sea water quality, the diversity of fauna species, the diversity of flora species, and a 1 %p reduction in marine litter as a result of conserving Incheon coastal sea water quality are estimated to be KRW 75, 135, 309 and 72 per household per year, respectively. All estimation results were statistically significant at the 1 % level. These findings can provide policy makers with useful information for evaluating and planning marine environmental management policies.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.475-481
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• 2018

In this study, the safety and effectiveness of ope cutter, developed to prevent frequent accident propeller windingness at sea. First, we calculated the bolt strength of the three types of rope cutting devices used in the experiment and the torsional stresses on the shafting system theoretical equation and the finite element method. As a result, the bolts used in the rope cutter confirmed from the viewpoint of safety life design and fail safe design. Also, safety satisfactory because of the small effect on the shaft system when locking up. Experiments were carried out to cut ropes and fishing nets from the sea using the ships equipped with three types of rope cutters verified to be safe. As a result, ropes of 20 to 50 mm in thickness were generally cut. It was found that the cutting efficiency of a rope cutter attached to shafting decreased when cutting thick ropes.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.304-311
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• 2021

This Experiment was conducted to determine the effects of light shield materials when melon grown inside a plastic greenhouse in summer season. The average temperatures were 36.6℃, 34.5℃ and 34.0℃ respectively for the control(non-shield), coating agent, and the white net. The light transmittances were 69% and 75%, respectively inside the greenhouse treated with the coating agent and white net immediately after applicants, compared with that inside the control greenhouse. At the 40 and 80 days after treatment, the light transmittances for the coating agent were 92% and 98%, respectively, indicating it was slowly decomposed and removed, but there was no change in the transmittance for the white net. While the leaf number did not differ among the treatments, the plant height was higher in the white net and shading agent than in control. The weight of the leaves, fresh-weight and dry-weight were no different from that of shading, but it became heavier in the later stages. The marketable fruit yield was increased by 6% for white nets and 5% for the coating agent compared to control, there was no statistical significance. Therefore, coating agent is considered as an effective method to lower temperature during high temperature period, but it is preferable to use it in consideration of cultivation period, because the coating agent is gradually removed.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.107-117
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• 2019

Because shipbuilding is single-product production with limited resources, production management technology is essential to manage the resources effectively and maximize the productivity of ship-process. Therefore, many shipbuilding companies are conducting research on ship production plan and process considering various constraints in the field by applying modeling and simulation. However, it is difficult to provide accurate production plan on sudden schedule and process changes, and to understand the interconnectivity between the processes that produce blocks in existing research. In addition, there are many differences between the production planning and field planning because detailed processes and quantity of blocks can not be considered. In this research, we propose the integrated process-based modeling method considering process-operation sequences, BOM(Bill of materials) and resource constraints of all the scheduled blocks in the indoor system. Through the integrated process-based model, it is easy for the user to grasp the assembly relationship, workspace and preliminary relationship of assembly process between the blocks in indoor system. Also, it is possible to obtain the overall production plan that maximizes resource efficiency without the separate simulation and resource modeling procedures because resource balancing that considers the amount of resource quantity shared in the indoor system is carried out.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1066-1076
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• 2018

Objective: The reliability of size measurements of liver metastases from neuroendocrine tumors (NETs) on contrast-enhanced computed tomography (CT) phases made by different readers may be hampered due to transient, variable rim enhancement in arterial phase (AP) or portal venous phase (PVP) images. We aimed to assess the reliability of tumor size measurements in pre- and post-contrast scans. Materials and Methods: The study coordinator selected target lesions according to Response Evaluation Criteria in Solid Tumors 1.1 guidelines in 44 consecutive patients with pathologically confirmed NET liver metastases. Two blinded readers measured the longest diameters of target lesions on pre-contrast, AP, and PVP images twice with a 4-week interval. Inter- and intra-observer agreements were evaluated using Bland-Altman plots and 95% limit of agreement (LOA) calculations. Results: Of the 79 target lesions (approximate mean size of 3 cm), 45 showed rim enhancement. Inter-observer agreement assessed based on LOA was highest in pre-contrast CT images (-6.1-5.7 mm), followed by PVP (-7.9-7.1 mm) and AP (-8.5-7.4 mm) images. Intra-observer agreement showed the same trend: -2.8-2.9 mm and -2.9-2.9 mm for readers 1 and 2, respectively, on pre-contrast CT, -2.8-2.9 mm and -3.0-3.2 mm, respectively, on PVP, and -3.2-4.2 mm and -3.4-3.2 mm, respectively, on AP images. Mean tumor diameters differed significantly among the phases in the following increasing order: pre-contrast CT, PVP, and AP images. Conclusion: There was better inter- and intra-observer agreement in size measurements of NET liver metastases on pre-contrast scans than on AP and PVP scans. Pre-contrast CT may be the optimal for measuring NET liver metastases if its accuracy is proven.

• Korean journal of applied entomology
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• v.58 no.2
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• pp.159-164
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• 2019

The purpose of this study was to investigate whether leaf damage in pear orchards caused by large black chafer beetles can be controlled through net traps and clove oil treatment. In June 2017, we measured large black chafer beetle population density and leaf damage rates in two orchards, located in Boseong and Hampyeong, under three treatments: net, net plus clove oil, and control. In order to evaluate the effect of net position on the adult beetles, nets were placed outside the orchard and along the upper and lower parts of a horizontal trellis. The adult beetle population density was 20.4 to 34.7% lower in the net alone treatment, and 21.1 to 38.1% lower in the combined net and clove oil treatment than in the control. The adult beetle population density was 10.9-14.4 times higher outside the orchard and 5.1 to 9.1 times higher in the upper parts of the horizontal trellis than in the lower parts of the horizontal trellis. Leaf damage under both the net only and net plus clove oil treatments was significantly lower than that in the control at both sites. Therefore, intensive net installation around orchards may be a practical organic alternative to prevent leaf damage caused by large black chafer beetles.

• Korean Journal of Ichthyology
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• v.31 no.1
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• pp.30-38
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• 2019

Egg development and early life history of the Korean endemic sand spine loach, Cobitis nalbanti, were investigated in the present study. Adult fish were sampled using spoon nets at the Yeongsan River in Seongam-ri, Bukha-myeon, Jangseong-gun, Jeollanam-do, Korea, June 2011. Eggs were obtained after injecting Ovarprim into females. Eggs were then artificially fertilized using the dry method in the laboratory. Mature eggs were transparent and slightly adhesive with light yellowish coloring, measured $0.99{\pm}0.03mm$ ($mean{\pm}SD$) in diameter. And number of spawned eggs were $1,527{\pm}410$ per individual. Hatching (50%) of the embryo occurred 52 hours after fertilization a water temperature of $25^{\circ}C$, and the average newly hatched larvae size was about $4.2{\pm}0.22mm$ in total length. At fifth day after hatching, the larval total length reached $6.0{\pm}0.34mm$ on average and their yolk sac had been completely absorbed. At fifteen day after hatching, larva entered the juvenile stage and reached $10.8{\pm}0.45mm$ in total length. At 100th day after hatching, the formation of Gambetta's zone of four dotted line was complete and juveniles were similar in general appearance to adults, and they averaged $41.1{\pm}2.95mm$ in total length.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.1
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• pp.82-93
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• 2019

The International Labor Organization (ILO) selected fishing as the most dangerous group of jobs in the world, and it is well known in Korea as a 4D industry. Offshore large purse seine accounts for the largest portion of the fishing industry in the coastal region with high death rate and the accident rate. The repeated disaster rate survey by the Korea Maritime Institute (KMI) shows offshore large purse seiner is the highest at 22.3 percent and coastal gill nets and offshore stow net are following at 12.4 percent and 11.9 percent in order. Therefore, risk factors occurring in offshore large purse seiners were analyzed based on data from the National Federation of Fisheries Cooperatives (NFFC) for three years from 2015 to 2017 and 4M (Man, Machine, Media, Management) 3E (Engineering, Education, Enforcement) techniques were used to provide a safe fishing environment. The number of accidents on offshore large purse seiners each year was more than 150, and the number of accidents on every fishing boats was as high as 17 percent in 2015. If the accident rate and the risk level were divided by insurance, the accident resulting from contact with machinery was the highest, and the risk of a contact with gear was low but frequently occurring. This was caused by collisions and contact with gear in situations where death and disappearance risk are not high, and accident types in situations where death and loss risk are considered to be contact with machinery, falls or other accidents. Through these analysis techniques, the frequency and risk of each type of accident on a offshore large purse seiners can be demonstrated, and it is expected to raise awareness of a safer fishing environment and contribute to the reduction of accidents.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.12
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• pp.439-451
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• 2019

This study is about the historical records of anchovy which has fluent nutritions as well as the representative side dish in Korean food culture and life. The formal first record about anchovy is in the Uhaeieobo written by Damjeung in 1803. Another important historical record about anchovy are Hyeonsaneobo(Jasaneobo) written by Jeong Yak-jeon in 1814, and Eomyeonggo(Fish name list) of Nanhoeomogji written by Seo Yu-gu in 1820. The anchovies were used for food in Korea even before the Chosun Dynasty, but they were not noticed by people. Because at that time, fishing tools and instruments such as nets were not developed enough to raise enough catches and food processing technology were not developed. Since then, in the Japanese colonial era, it has been actively developing agricultural fertilizers using anchovies. In addition, the processing technology that can be used as an edible food using anchovy has been rapidly developed. Now, the anchovy industry has very important position in Korea's fisheries industry. Among them, 'Jukbangryum anchovy' catching bamboo weir tool which has been existed for over five hundred years in Namhae province, not only creates great high economic value, but also has cultural value. Therefore, the historical literature study on anchovy can be used as an invaluable resource not only for the study of fishery from an industrial point of view, but also for the registration of world cultural heritage and GIAHS (Globally Important Agricultural Heritage System) of 'Jukbangryum' which is traditional fishery catching instrument in Korea.