• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.152-157
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• 2001

This paper was studied on the characteristics of crevice corrosion prevention of SS 400 in marine environment. In NaCl solution, polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 applied cathodic protection and non cathodic protection was measured according to the NaCl concentration. The main results obtained are as follows : The weight loss rate of Al-alloy galvanic anode was increased as the concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, that of Al-alloy galvanic anode become decreased. The protective potential of SS 400 used Al-alloy galvanic anode becomes more cathodic polarization with increasing concentration of NaCl solution. Effects of oxygen on the weight loss rate of Al-alloy sacrificial anode for cathodic protection as the concentration of 3.5% NaCl solution become sensitive than that of 0% NaCl solution.

• Journal of Environmental Analysis, Health and Toxicology
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• v.21 no.4
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• pp.252-263
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• 2018

Distributions of 15 PAHs and 82 PCBs were investigated in sediment and fish samples collected from the Suyoung Estuary of Busan, one of the most urbanized and newly contaminated areas in Busan. The concentrations of $S_{15}PAH$ in sediments ranged from 17.9 to 777 ng/g-dry and were mainly originated from combustion processes. The concentrations of $S_{82}PCB$ in sediments ranged from 0.55 to 12.5 ng/g-dry and were significantly correlated with those of 12 dioxin-like PCBs and 6 non-dioxin like PCBs. Higher concentrations of PAHs and PCBs were found in the upper river and the inner Suyoung Bay than in marina and the outer Suyoung Bay. No sites exceeded the ecotoxicological values of PAHs and PCBs in marine sediments. Benzo[a]-pyrene was not detected in fish samples and the concentrations of $S_4PAH$ (0.15~0.45 ng/g-wet) were lower than the maximum level set by EU. The levels of PCBs in fish samples were at less than 1% of the Korean maximum level and 2% of the EU maximum level. The concentrations of dioxin-like PCBs were $0.01{\sim}0.32pg-TEQ_{WHO-2005}/g-wet$, and the highest concentration was found in eels, which were at less than 5% of the EU maximum level. Dietary intakes of PAHs and PCBs through fish consumption were estimated, and their lifetime cancer risk and non-cancer risk were much lower.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.316-322
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• 2002

A newly isolated heterotrophic marine bacterium, Vibrio alginolyticus, was used to remove a high load of ammonia gas under non-sterile condition. The cells were inoculated onto an inorganic packing material in a fixed-bed reactor (biofilter), and a high load of ammonia, in the range of ammonia gas concentration of 170 ppm to 880 ppm, was introduced continuously. Sucrose solution and 3% NaCl was supplied intermittently to supplement the carbon source and water to the biofilter. The average percentage of gas removed exceeded 85% for 107-day operation. The maximum removal capacity and the complete removal capacity were$19\;g-N\;kg^{-1}$ dry packing material $day^{-1}$ and $16\;g-N\;kg^{-1}$ dry packing material $day^{-1}$, respectively, which were about three times greater than those obtained in nitrifying sludge inoculated onto the same packing material. On day 82, the enhanced pressure drop was restored to the normal one by NaOH treatment, and efficient removal characteristics were later observed. During this operation, the non-sterile condition had no significantly adverse effect on the removability of ammonia by V. alginolyticus.

• The Journal of Fisheries Business Administration
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• v.47 no.4
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• pp.45-55
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• 2016

The purpose of this study is to estimate the utility value of boat fishing experience marine tourism activity in Jeju Island's Chagwido. The utility value is estimated by single bounded and double-bounded dichotomous choice contingent valuation method. The contingent valuation method is used to estimate economic values for all kinds of coastal ecosystem services. The method involves directly asking people, in a survey, how much they would be willing to pay for specific environmental services. So, the method has great flexibility, allowing valuation of a wider variety of non-market goods and services than is possible with any other non-market valuation technique. This study collects the effective 504 questionnaires from boat fishing experience tourists in Jeju Island's Chagwido. The results show that the average willingness to pay amount(WTP) is estimated to be about 17,000 Korea won by single bounded and double-bounded dichotomous choice contingent valuation method. This indicates that the utility value of boat fishing experience marine tourism activity is estimated to be about 17,000 Korea won in Jeju Island's Chagwido.

• Journal of fish pathology
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• v.24 no.3
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• pp.297-305
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• 2011

A trap identification system for isolating functional sequences to allow the constitutive expression of foreign protein from Edwardsiella tarda was developed. Using the green fluorescent protein (GFP) reporter-based trap system, various functional sequences to drive heterologous expression of the GFP were selectable in Escherichia coli host. However from the bioinformatic sequence analysis, all the segments predicted as regulatory regions were not native promoters actually existing upstream of endogenous E. tarda genes. Instead, a number of non-authentic sequences, possibly resulted from the random shuffling and/or intermolecular ligation were also proven to be able to display a potent GFP expression in the recombinant E. coli. Further analysis with selected clones showed that both authentic and non-authentic sequences could function in as a constitutive promoter, leading quite a consistent and stable GFP expression after repetitive subcultures. Microscopic examination also confirmed the uniform pattern of GFP expression in every host bacterium. Semi-quantitative assay of GFP showed that there was no clear relationship between expression levels and organizational features of the promoters trapped. Functional promoter-like elements achieved in the present study could be a good starting material for multivalent genetic engineering of E. tarda in order to produce recombinant vaccines in a cost-effective fashion.

• The Journal of Fisheries Business Administration
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• v.40 no.3
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• pp.127-146
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• 2009

This study is to estimate the factor weights of the reasons for decreases in marine fishery resources using the Analytical Hierarchy Process. Furthermore, it classifies 20 fishes under a fishery resource recovery plan into various groups of fishes according to these factor weights using the non-hierarchial cluster analysis. The factors of decreases in marine fishery resources are identified as bio-ecological, technology-system, economic-business, and fishing village-society factors. Two of the most important factors of decreases in resource are turned out to be the economic-business and bio-ecological factors, estimated as 31% and 30% respectively. The technology-system and fishing village-society factors are estimated as 21% and 18% respectively. The study utilizes non-hierarchical cluster analysis in order to classify 20 fishes into 2, 3, and 4 groups. K-means cluster analysis is applied for grouping in conjunction with ANOVA to identify statistical differences in factors. Once again, the economic-business and bio-economic factors play main role in grouping 2-groups of fishes case. The third group of fishes in addition to the previous 2 groups of fishes appears as those 4 factors of decrease evenly play about the same role at a 3-groups of fishes case. Finally, the economic-business and bio-economic factors are turned out to be evenly important in the 4th group once there are 4-groups of fishes.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.4
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• pp.439-449
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• 2018

In this paper, multi-objective optimization of a multi-bubble pressure cabin in the underwater glider with Blended-Wing-Body (BWB) is carried out using Kriging and the Non-dominated Sorting Genetic Algorithm (NSGA-II). Two objective functions are considered: buoyancy-weight ratio and internal volume. Multi-bubble pressure cabin has a strong compressive capacity, and makes full use of the fuselage space. Parametric modeling of the multi-bubble pressure cabin structure is automatic generated using UG secondary development. Finite Element Analysis (FEA) is employed to study the structural performance using the commercial software ANSYS. The weight of the primary structure is determined from the volume of the Finite Element Structure (FES). The stress limit is taken into account as the constraint condition. Finally, Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) method is used to find some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. The best solution is compared with the initial design results to prove the efficiency and applicability of this optimization method.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.303-310
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• 2011

We characterized a cytoplasmic actin gene locus in greenling Hexagrammos otakii (Scorpaeniformes). Genomic clones isolated from the greenling DNA library contained two homologous cytoplasmic actin gene copies (HObact2.1 and HObact2.2) in a tail-to-head orientation. Their gene structure is characterized by six translated exons and one non-translated exon. Exon-intron organization and the nucleotide sequences of the two actin gene isoforms are very similar. However, only the HObact2.1 isoform contains microsatellite-like, dinucleotide repeats in the 5'-flanking region (named HOms2002) and intron 1 following the non-translated exon 1 (named HOms769). One microsatellite locus (HOms769) was highly polymorphic while the other (HOms2002) was not. Based on bioinformatic analysis, different transcription factor binding motifs are related to stress and immune responses in the two actin isoforms. Semiquantitative and real-time reverse transcription-PCR assays showed that both isoform transcripts were detectable ubiquitously in all the tissues examined. However, the basal expression levels of each isoform varied across tissues. Overall, the two isoforms showed a similar, but not identical, expression pattern. Our data suggest that the cytoplasmic actin genes may be the result of a recent duplication event in the greenling genome, which has not experienced significant subfunctionalization in their housekeeping roles.

• Fisheries and Aquatic Sciences
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• v.22 no.7
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• pp.14.1-14.8
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• 2019

Olive flounder (Paralichthys olivaceus) is the major species developed for aquaculture in South Korea. Over the long history of olive flounder aquaculture, complex and diverse diseases have been a major problem, negatively impacting industrial production. Vibriosis is a prolific disease which continuously damages olive flounder aquaculture. A bacterial disease survey was performed from January to June 2017 on 20 olive flounder farms on Jeju Island. A total of 1710 fish were sampled, and bacteria from the external and internal organs of 560 fish were collected. Bacterial strains were identified using 16 s rRNA sequencing. Twenty-seven species and 184 strains of Vibrio were isolated during this survey, and phylogenetic analysis was performed. Bacterial isolates were investigated for the distribution of pathogenic and non-pathogenic species, as well as bacterial presence in tested organs was characterized. V. gigantis and V. scophthalmi were the dominant non-pathogenic and pathogenic strains isolated during this survey, respectively. This study provides data on specific Vibrio spp. isolated from cultured olive flounder in an effort to provide direction for future research and inform aquaculture management practices.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.541-551
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• 2020

Based on the trend, there have been numerous researches analysing the ship collision risk. However, in this scope, the navigational conditions and external environment are ignored or incompletely considered in training or/and real situation. It has been identified as a significant limitation in the navigational collision risk assessment. Therefore, a novel algorithm of the ship navigational collision risk solving system has been proposed based on basic collision risk and vulnerabilities of marine accidents. The vulnerability can increase the possibility of marine collision accidents. The factors of vulnerabilities including bad weather, tidal currents, accidents prone area, traffic congestion, operator fatigue and fishing boat operating area are involved in the fuzzy reasoning engines to evaluate the navigational conditions and environment. Fuzzy logic is employed to reason basic collision risk using Distance to Closest Point of Approach (DCPA) and Time of Closest Point of Approach (TCPA) and the degree of vulnerability in the specific coastal waterways. Analytical Hierarchy Process (AHP) method is used to obtain the integration of vulnerabilities. In this paper, vulnerability factors have been proposed to improve the collision risk assessment especially for non-SOLAS ships such as coastal operating ships and fishing vessels in practice. Simulation is implemented to validate the practicability of the designed navigational collision risk solving system.