• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.423-428
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• 2009

Recently, the marine traffics have been increased along with enlargement of overseas commerce. Increasing the marine traffic may make higher the risk of marine accidents. Especially, the rate of accidents on costal area are more frequently. As if the marine safety information can be afforded to vessel and shore, the accident rate would be down. AIS AtoN is the navigational safety support device which is subject to functional requirements of IALA and technical standards of ITU. In this paper, we extend and implement the user-defined specification of AIS AtoN with message 21 for AIS basic information, messsage 6 for status report and message 12/14 for safety management.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1053-1062
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• 2015

This research assesses the implementation of the bilateral fisheries order of the China-Japan fisheries agreement. After establishment of UNCLOS, the China-Japanese fisheries agreement has played as a basis for the fisheries order in the East China Sea. The China-Japanese fisheries agreement intends that the fisheries industries in China and Japan can utilize the renewable natural resources in the East China Sea. As the EEZ of China overlaps with that of Japanese in the East China Sea, the two countries established the China-Japan Provisional Measure Zone and Middle Zone in the Sea. Even though the three coastal States (e.g. Korea, China, and Japan) in the East China Sea are involved in managing these zones, there has been little effort to coordinate each county's management. Additionally, the Taiwan-Japan fisheries agreement, which is for the area of N $27^{\circ}$, has made costal States to establish and implement united measures to conduct effective fisheries management. Regarding access to the joint fishing zone in EEZ, Chinese fisheries regulations have been enforced in the zone because the fishing capacity of China exceeds all of other countries, reducing the number of fishing licenses and catch quotas. It turned out that a nation that has authority over fisheries resources tends to establish specific conditions of fishing operations to maximize its national interest. In the China-Japan Provisional Measure Zone, Chinese and Japanese authorities have introduced united measures to manage fisheries resources. However, in the Middle Zone between China and Japan, there is no regulation on fishing; both countries' fishing vessels can have free access to the zone. Thus, it is recommended that one should introduce an international fisheries management regime for the Middle Zone. In this regard, Korea should play a leading role in establishing the international management regime because Korea has middle position in terms of geographical standpoint, the degree of dependence on commercial fishing, and its fishing capacity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1450-1456
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• 2015

The received signal strengths according to the propagation distance between a transmitting shore station with a 53 m antenna hight and a receiving ship station with about 6m antenna hight from 700 m upto about 20 km are measured at ship's moving velocity of $5{\pm}1m/s$ using a single carrier signal at 150.0625MHz. In this paper, the path loss exponents at the propagation distance from 700 m to 20km are estimated via minimum-mean-square-error method using the measurements of the received signal strength, and the mean of the estimated path loss exponent become 3.79. The estimated propagation path loss exponents is similar to that calculated based on the field-strength values from 2 km to 20 km in Annex 2 of ITU-R P.1546-4, which is measuring results at maritime VHF at 100 MHz carrier frequency. Therefore, the estimated propagation path loss exponent shall be used as the expected path loss exponents for summer in costal area of South Sea of Korea.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.74-80
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• 2005

For the reseach of the natural marine antioxidant, an antioxidant-producing bacterium was isolated from seawater in Jeju costal area. The isolated strain SC2-1 was Gram-positive, catalase positive, oxidase negative, motile and small rods. The strain utilized sucrose, dextrose, fructose, mannitol and maltose as a sole carbon and energy source and NaCl required for growth. The radical scavenging activity of the culture supernatant was detemined by DPPH method. This bacterium was identified based on morphological, biochemical characteristics and 16S rDNA sequence analysis, and then was named Exiguobacterium sp. SC2-1. The optimum conditions of culture for production antioxidnat were $25^{\circ}C$, pH 6-8 and $4\%$ NaCl. The stain showed the highest activity and growth cultured in medium which added $1\%$ maltose. Hydroxyl radical activity of the supernatant of Exiguobacterium sp. SC2-1 was $73\%$. The SOD activity of the culture supernatant was estimated about $35\%$.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.607-616
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• 2014

This research is to observe the shoreline changes in Jinha beach over the 50 years with aerial photographs and satellite images. The shoreline image feature was retrieved from the corrected images using wet and dry techniques and analyzed by DSAS from the statistical point of view. From 1967 to 1992, the mouth of Hoeya River was severely blocked and the northern shoreline off Jinha beach was eroded. The blockade of river mouth seemed to have been eased along with the completion of the dike, but soil continued to be deposited along the high sea away from the river month. Compared to the past, a layer of sediment has been formed off the northern coastline while the southern coastline has eroded. At least in the region subject to this research, the construction of a training dike is to blame. On top of that, a mere combination of dredges and artificial nourishment is not enough to take under control the changing shorelines properly. Thus, it is necessary to devise a more fundamental solution by taking into account reasons behind sediment from the river area that could change the shorelines besides the costal environment.

• 한국해양학회지
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• v.26 no.3
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• pp.242-254
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• 1991

Southern sea of Korea was investigated for primary productivity during four scientific cruises of Korea Ocean research and Development Institute. Frontal structure appeared to be an important physical characteristic in enhancing the phytoplankton production in the study area. Relatively high productivity was occurred near the front between Tsushima Warm Current Water and Coastal Waters of China continent in March 1990 and in November 1989, and near the front between Tsushima Warm Current Water and Korean coastal Water in April 1989. In August 1988 high productive zone was limited to the tidal front off the southwestern coast of Korea. Nutrient supply related to the frontal structure might play a dominant role in increasing the primary productivity but mechanisms of nutrient enrichment are not clear. Average column productivity showed its maximum in April 1989 (1727 mgC/m$^2$/day). In the costal Waters of the china Continent incident light may be an important factor in regulating the regulating the phytoplankton production because of low light penetration rate resulting from high turbidity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.2
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• pp.94-108
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• 1993

In order to investigate the relation between the environmental properties and catch fluctuation of set net fishing ground located in the coastal waters of Yeosu, oceanographic observation and catches on the grounds were carried out from Jan. to Dec. in 1990 and 1992. The results obtained are summarized as follows; 1) Because of the surveyed area is a costal shallow water, the fishing ground was influenced largely by atmospheric phenomena such as air temperature. precipitation. etc. and so showed large variations in temperature and salinity yearly. The inner water flowed out mainly between Yeosu ad Namhe-do, and then through Kumo-do between Dolsan-do and Kumo-do. On the other hand, off shore water was supplied into the fishing ground from the vicinity of Sori-do and Yokchi-do. thus the fishing ground was occupied usually by various sources of water. 2) The water mass in the fishing ground were divided into the inner water(29.0～30.6$\textperthousand$) and the mixed water(31,7～32.2$\textperthousand$) and off shore water(32.3～32.8$\textperthousand$) accourding to the distribution of salinity from T-S diagram plotted all salinity data observed in 1990 and 1992. In summer the inner and mixing water which was formed by river flowed southerly and spread south-easterly in the vicinity of Kumo-do. The off shore water which supplied from the vicinity of Sori-do and Yokchi-do and inner water formed the thermal front and halo front in summer. 3) The fishes caught by the set net were arranged in the order of catch amounts as follows: Spanish mackerel>Horse mackerel >Hair tail>Common mackerel> Sardine> Anchovy. The Catches of anchovy and sardine were high in April to May and those of hair tail and horse mackerel in July to September, but spanish mackerel were caught during the whole period of fishing. When inner water and mixing water appeared respectively and inner water and mixing water speared together in the set net fishing ground, the set net showed a high catch.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.684-689
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• 2017

We examined the possibility of developing an early monitoring system using the shell valve movement activity of Pacific oyster (Crassostrea gigas) for early detection of low salinity water in coastal areas. At salinity levels of 30 psu and 20 psu, SVMs were detected $7.32{\pm}3.21times/hr$ and $7.11{\pm}3.90times/hr$, respectively, The patterns and times of SVMs were not significantly different between the two experiment phases. However, at 10 psu and 5 psu, shell valves were observed to be permanently closed in all experiments. Under combined condition (Group 1: temperature $15^{\circ}C$ ${\times}$ salinity 15 psu), SVMs were observed from 20 psu to 30 psu over a 2 - 3 hr period, and then remained closed. In Group 2 (temperature $30^{\circ}C$ ${\times}$ salinity 15 psu), SVMs were observed, which indicated that the physiological condition of the oysters reached a critical point. Thus, it may be possible to utilize SVMs as an early warning signal for low salinity water.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.1
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• pp.11-21
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• 2000

Most of artificial reefs in the examined areas were normally established except for some lower parts demersed slightly, and some to function. 1) Twenty species of fish were captured by fishing gear, and 10 species were observed by scuba in the examined areas. 2) Five algal and five fisheries animal species were observed as fouling organism. 3) C.P.U.E of trap, long liner and gill netter in the examined areas was respectively 2.12, 10.23, and 4.93, where as that in contral was established as 1.41, 4.43 and 2.86. 4) Species composition by the fishing gear the trap, long liner and gill netter in the examind areas was respectively 94, 85 and 118, where as that in control was established as 58, 37 and 62. Accordingly, The fishing effects in the artificial reefs installation sector was two times higher than comparative sector.

• Geophysics and Geophysical Exploration
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• v.21 no.4
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• pp.244-254
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• 2018

The first geophysical technique applied to the agricultural sector in Korea was electrical resistivity sounding and conducted in purpose of groundwater exploitation in the 1970s. According to the diversity of agricultural activities since the 1990s, various geophysical methods including electrical resistivity, electromagnetic induction, and self-potential method were applied to several agricultural fields such as soil characterization with saline concentration in vast reclaimed area, delineation of seawater intrusion regions in costal aquifer, safety inspection of embankment dikes with leakage problem, detection of ground subsidence from overpumping and tracing of groundwater aquifer contamination by leachate from livestock mortality burial or waste burial site. This paper introduces representative geophysical techniques that have been utilized in various agricultural fields and suggests several ways to develop the geophysical methods required for the precision agriculture field in the near future based on the past achievements.