• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.217-217
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• 2017

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.218-218
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• 2017

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.2
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• pp.252-260
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• 2016

Unlike terrestrial transportation, marine transportation should consider environment factors in order to optimize path planning. This is because, ship's path planning is greatly influenced by real-time ocean environment-sea currents, wave and wind. Therefore, in this study, we suggest a ship path planning algorithm based on real-time ocean environment using not only $A^*$ algorithm but also path smoothing method. Moreover, in order to improve objective function value, we also consider ship's moving distance based on ship's location and real-time ocean environment data on grid map. The efficiency of the suggested algorithm is proved by comparing with $A^*$ algorithm only. This algorithm can be used as a reasonable automatics control system algorithm for unmaned ship.

• Ocean and Polar Research
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• v.44 no.4
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• pp.287-296
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• 2022

High-frequency (HF) radar measures sea surface currents from the radio waves transmitted and received by antenna on land. Since the data quality of HF radar measurements sensitively depend on the radio wave environment around antenna, Antenna Pattern Measurements (APM) plays an important role in evaluating the accuracy of measured surface currents. In this study, APM was performed by selecting the times when the background noise level around antenna was high and low, and radial data were generated by applying the ideal pattern and measured pattern. The measured antenna pattern for each case was verified with the current velocity data collected by drifters. The radial velocity to which the ideal pattern was applied was not affected by the background noise level around antenna. However, the radial velocity obtained with APM in the period of high background noise was significantly lower in quality than the radial velocity in a low noise environment. It is recomended that APM be carried out in consideration of the radio wave environment around antenna, and that the applied result be compared and verified with the current velocity measurements by drifters. If it is difficult to re-measure APM, we suggest using radial velocity in generating total vector with the ideal pattern through comparative verification, rather than poorly measured patterns, for better data quality.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.415-420
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• 2010

"Journal of the Korean Society of Marine Environment & Safety" is representative scientific journal about ocean environment and ocean safety in Korea. This study analyzed research trend of "Journal of the Korean Society of Marine Environment & Safety" through review of articles published in the journals for 10 years tram 2000 to 2009. On the basis of the pursuit of learning and academic constitution of "The Korean Society of Marine Environment & Safety", criteria items of analysis for research trend such as authors institution of employment, region of authors' institution, form of participation in research, article's educational nature, article's method of study, article's area of study, etc. were set up and applied to 310 research articles published in "Journal of the Korean Society of Marine Environment & Safety" for 10 years.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.39-43
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• 2009

A flow and low temperature of deep seawater the biofouling properties in a seawater environment of different materials, such as a steel pipe, polyethylene pipe, and nylon net, used for ocean industries. Experiments in a real sea environment were performed to grasp the quantitative and qualitative biofouling from diatoms attached to materials by measuring the Chlorophyll-a density. Experimental samples were placed under five types of ocean environmental conditions and analyzed every month for five months. It is shown that the biofouling by diatoms was strongly affected by the seawater temperature for all of the experimental samples. It was found that diatoms mainly adhered to the nylon net, while crustaceans prefer polyethylene, under a high temperature condition. It is believed that the biofouling properties are strongly related to the surface roughness of a material. The biofouling under the low temperature condition of deep seawater was rare and stable for the experimental periods. The inside of a pipe conveying deep seawater can be presumed to remain clear without biofouling on the condition of a flow and low temperature of deep seawater.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.545-555
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• 2007

Ocean general circulation model developed by GFDL on the basis of MOM4 of FMS are examined and evaluated in order to elucidate the global ocean status. The model employs a tripolar grid system to resolve the Arctic Ocean without polar filtering. The meridional resolution gradually increases from $1/3^{\circ}$ at the equator to $1^{\circ}$ at $30^{\circ}N(S)$. Other horizontal grids have the constant $1^{\circ}$ and vertical grids with 50 levels. The ocean is also coupled to the GFDL sea ice model. It considers tidal effects along with fresh water and chlorophyll concentration. This model is integrated for a 100 year duration with 96 cpu forced by German OMIP and CORE dataset. Levitus, WOA01 climatology, serial CTD observations, WOCE and Argo data are all used for model validation. General features of the world ocean circulation are well simulated except for the western boundary and coastal region where strong advection or fresh water flux are dominant. However, we can find that information concerning chlorophyll and sea ice, newly applied to MOM4 as surface boundary condition, can be used to reduce a model bias near the equatorial and North Pacific ocean.

• Ocean and Polar Research
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• v.33 no.3
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• pp.255-263
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• 2011

The aim of this investigation was to evaluate antioxidant activity of crude extracts from the halophyte Vitex rotundifolia, their solvent fractions, and isolated compounds (1-3). Antioxidant capacity was determined by measuring DPPH radical, and authentic $ONOO^-$ and $ONOO^-$ generated from 3- morpholinsydnonimine (SIN-1) in vitro as well as degree of occurrence of intracellular ROS, NO and GSH in mouse macrophage Raw 264.7 cells. From comparative analysis, MeOH extract, n-BuOH, and 85% aq. MeOH solvent fractions showed significant antioxidant effect in DPPH radical and $ONOO^-$ assay systems. Activity-guided purification of n-BuOH and 85% aq. MeOH fractions led to the isolation of flavonoids 1-3. Among them, compound 1 exhibited excellent antioxidant effect in all bioassay systems tested. On the other hand, compounds 2 and 3 revealed potent inhibitory effect against $ONOO^-$ generated from SIN-1, comparable with the positive control penicillamine.

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.226-229
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• 2007

Survival, tag retention and tag readability were compared among the control and three treatment groups of soft-shelled turtles, Pelodiscus sinensis Crother, 2000 (mean body $weight{\pm}SD$: $182.6{\pm}13.7\;g$), marked with visible implant fluorescent elastomer (VIFE) tags for 16 months. Mortality 4 to 16 months after tagging was attributed to collection and handling stress rather than to the tagging itself. Tags applied to the web surface between the fourth and fifth dactyl of the hindfoot appeared to have the highest retention rates, while adipose eyelid tagging had high tag readability but a high loss rate. We conclude that in soft-shelled turtles, the most suitable region for VIFE tagging is on the web surface between the fourth and fifth dactyls of the hindfoot.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.812-817
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• 2017

This study evaluated the effects of dietary inclusion of soybean (SM) and fermented soybean meal (FSM) on growth promotion in juvenile abalone Haliotis discus. Six hundred and thirty juvenile abalone were distributed into nine plastic containers. Three diets were prepared with 22% fish meal, 2% casein, and either 25% SM or FSM used as the protein sources in the experimental diets, and Undaria was used as a control diet to compare the effects of the experimental diets on the growth performance of abalone. The diets were assigned to three containers each and fed to the abalone once daily to satiation for 16 weeks. Weight gain and specific growth rate (SGR) were higher in abalone fed the SM diet than in those fed the FSM diet. Weight gain and SGR of abalone fed the SM and FSM diets were higher than those of abalone fed Undaria. The crude protein and lipid contents of the edible portions of abalone fed the SM and FSM diets were higher than those of abalone fed Undaria. SM was superior to FSM as a protein source in abalone feed. The SM and FSM diets facilitated greater growth than Undaria.