• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.4
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• pp.151-156
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• 1987

The author carried out an experiment to find out the response of sea-bass, Epinephelus septemfasciatus (Thunberg) to the color lights. The experimental tank (360L$\times$50W$\times$55H cm) was set up in a dark room. Six longitudinal sections with 60 cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50 cm level. Light bulbs of 20 W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in the order of blue, red, white and yellow in day time, and red, blue, yellow and white at night time. The gathering rate of fish on illumination period was not constant and fluctuated with irregularity. The difference of the gathering rate on two different colors of light was small and the difference was larger in night time then in day time.

• Spatial Information Research
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• v.23 no.5
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• pp.21-30
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• 2015

Korean government has promoted the projects of National Geographic Information Systems since 1995 and the utilization level of Korean National Spatial Data Infrastructure based on them has also developed. However, due to the limit to domestic market size and the legal regulation on prohibition of large sized companies' expansion into domestic spatial information markets, Korean spatial information markets are tied up in term of industrial competitiveness. To overcome those problems and evade the domestic red oceans, it is necessary to find new one in overseas' blue ocean markets. It is estimated that overseas spatial information market will be grown to 125 billion-dollar size and the annual growth rate of it will be reached to 10.5% until 2015. Thus, Asian spatial information market has a huge growth potential and it is newly rising blue oceans for Korea. Advanced countries such as Finland, Germany, Sweden, and Japan have already expanded their market size into the newly industrializing countries. To step with advanced countries, it is time to set up the new globalization strategy of Korean spatial information for expansion into newly industrializing markets. The purpose of this study is to analyze the SWOT of domestic spatial information, investigate the status on spatial information of Asian developing countries, and suggest the globalization strategy of Korean spatial information for expansion into them. The globalization strategy can be labelled as K-FBI composed of 4 domains such as Knowledge sharing platform, Frontier, Back to the basic, and Internalization. In near future, the establishment and performance of road map based on the strategy will be the milestone for Korean spatial information companies' advance into Asian developing countries.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.3
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• pp.213-219
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• 1995

The author carried out an experiment to find out the response of Black porgy, Acanthopagrus schlegelii [Bleeker] to the color lights. The experimental tank ($360L{\times}50W{\times}55H$cm) was set up in a dark room. Six longitudinal sections with 60cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50cm level. Light bulbs of 20 W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity was controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in order of blue, yellow, white and red in the day-time and blue, red, yellow and white at night. The difference of the average distribution on two different colors of light was 7.18%(0.35-19.55%), and the difference in the daytime(8.20%) was larger than at night (6.15%). The gathering rate of fish on illumination period didn't show the regular trend of increase and decrease, and was fluctuated with instability. The difference of the gathering rate on two different colors of light wasn't distinct, and the difference in the daytime was larger than at night.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.90-95
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• 2010

Blue devil (Pomacentrus caeruleus, also called Chrysiptera cyanea) is widespread in the Indo-Pacific Ocean and very popular all over the world as an aquarium fish because it is so easy to keep in a marine aquarium. However, tank-breeding techniques are not completely known. In this study, we reared blue devil and investigated its spawning ecology, as a necessary precursor for successful artificial-tank breeding. We investigated the spawning volume according to time with two types of calendars: solar and lunar. Rearing conditions were set at 30 ppt salinity, $27^{\circ}C$ water temperature, in two aquariums with water volumes of 80 and 125 L. We successfully bred P. caeruleus in this artificial-tank system. The aquarium fish formed a spawning harem with one male and more than two females. We harvested about 113,580 eggs in 44 spawning episodes by two spawning harems during the 11-month period from December to October. They showed a peak season of spawning volume and time in May and June. We confirmed the two peak points in spawning volumes and times, which coincided with the first quarter and last (third) quarter of the lunar phases of the moon.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.3
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• pp.167-174
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• 2021

In this study, the amount and frequency characteristics of cloud cavitation formed on a navy ship rudder were investigated through cavitation image processing technique and cavitation noise analysis. A high-speed camera with high time resolution was used to observe the cavitation on a full-spade rudder. The deflection angle range of the full-spade rudder was set to 8 to 15 degrees so that cloud cavitation was generated on the rudder surface. For images taken at 10⁴ fps (frame per second), reference values for detecting cavitation were defined and detected in Red, Green, Blue and Hue, Saturation, Lightness color spaces to quantitatively analyze the amount of cavitation. Intrinsic frequency characteristics of cloud cavitation were detected from the time series data of the amount of cavitation. The frequency characteristics of cloud cavitation obtained by using the image processing technique were found to be the same through the analysis of the noise signal measured by the hydrophone installed on the hull above the rudder, and its peak value was in the frequency band of 30~60Hz.

• The Journal of the Korea Contents Association
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• v.12 no.10
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• pp.116-127
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• 2012

With the recent rapid growth in the number of people who enjoy marine and leisure activities in Korea, the marine leisure industry faces good opportunities for development. Korean brands are in between them. In this situation, new and innovative products related to an inflatable tube, which is one of the most popular marine leisure items, will help to increase sales of domestic companies and to pioneer a new market. Research methods are largely divided into 4: investigation, analysis & synthesis, development and evaluation. This paper introduces a "tube cushion" which is an inflatable tube covered by fabrics. It can be functioned at home 365 days a year as a cushion or a children's plaything. Tactile fabrics, neoprene and air-mesh, are used as the cover with a zipper, making it easy to open and close. Moreover, by putting together tubes and connecting them with snap fastener attached straps, the cushion can be transformed into a chair, a table, a tunnel, a train, and so on, serving as a creative plaything for children. With this paper, it is expected that new and innovative items differentiated from others, like this crossover tube cushion, will help to create a 'Blue Ocean' market for the marine leisure industry from the long-term perspective.

• ALGAE
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• v.20 no.1
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• pp.43-52
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• 2005

A study on the seasonal changes in the phytoplankton community was carried out in four aquaculture ponds of Bangladesh over a period of 16 months from August 2000 to November 2001. Out of 45 phytoplankton species identified, 30 belong to Cyanophyceae, 7 to Chlorophyceae, 5 to Bacillariophyceae and 3 to Euglenophyceae. The highest phytoplankton abundance was observed in spring followed by early autumn, summer, and the lowest was in winter. The annual succession of Cyanophyceae was characterized by spring and early autumn period dominated by Microcystis sp. Anabaena sp. and Planktolymbya sp. with Microcystis sp. as the main blue-green algae represented. Chlorophyceae was characterized by rainy season domination of Chlorella vulgaris, Pediastrum sp. and Scenedesmus denticulatus with maximum abundance of Chlorella vulgaris. Whereas Bacillariophyceae was dominant during the winter period. Navicula angusta and Cyclotella meneghiniana were the most frequently occurring species of Bacillariophyceae throughout the study period. Euglenophyceae was dominant in late autumn and Euglena sp. was the dominant species. The effect of various physicochemical water quality parameters on the seasonal distribution and succession of the above mentioned phytoplankton population as well as the interaction and eutrophication are discussed.

• Ocean and Polar Research
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• v.31 no.3
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• pp.257-264
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• 2009

Seventeen females of the mud crab Scylla serrata, from the State of Kosrae, Micronesia, were transported to the Fisheries Resources Research Institute, Gyeongsangnam-do, in oxygen-filled plastic bags. After acclimatization to a $30^{\circ}C$ holding temperature, nine females were selected for seed production trials. Spawning was hastened using eyestalk ablations; however, this may not be required in commercialscale mud crab seed production. Primary spawning produced an average of 2.4 million hatched larvae, whereas secondary spawning produced 0.4 million. About 10 days elapsed between spawning and hatching and 30 days between hatching and crablet. Mass mortalities up to 90% were observed between stages zoea 1 and zoea 2 in every trial. The highest survival rate from zoea 1 to crablet was estimated at 0.25%. Most commercial shrimp hatcheries in Korea are equipped with almost all necessary facilities and could be converted easily to mud crab hatcheries, able to run three to four times per year using hatchery technologies developed for blue crabs and Chinese mitten crabs.

• Korean Journal of Ichthyology
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• v.20 no.4
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• pp.324-326
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• 2008

One specimen (103.7 mm SL) of Lactoria fornasini, belonging to the family Ostraciidae, collected from the coastal waters of Jeju Island, marks the first record of the species from Korea. It is characterized by having a strongly curved spine on the dorsal ridge, a pair of short spines in front of the eyes, a pair of spines projecting posteriorly from the rear end of the ventrolateral ridge, and wavy blue lines on the body. We add this species to the Korean fish fauna and propose its new Korean name, "Jul-mu-nui-ppul-bok."

• Journal of Environmental Science International
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• v.10 no.6
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• pp.431-436
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• 2001

Variations in phytoplankton concentrations result from changes of the ocean color caused by phytoplankton pigments. Thus, ocean spectral reflectance for low chlorophyll waters are blue and high chlorophyll waters tend to have green reflectance. In the Korea region, clear waters and the open sea in the Kuroshio regions of the East China Sea have low chlorophyll. As one moves even closer In the northwestern part of the East China Sea, the situation becomes much more optically complicated, with contributions not only from higher concentration of phytoplankton, but also from sediments and dissolved materials from terrestrial and sea bottom sources. The color often approaches yellow-brown in the turbidity waters (Case Ⅱ waters). To verify satellite ocean color retrievals, or to develop new algorithms for complex case Ⅱ regions requires ship-based studies. In this study, we compared the chlorophyll retrievals from NASA's SeaWiFS sensor with chlorophyll values determined with standard fluorometric methods during two cruises on Korean NFRDI ships. For the SeaWiFS data, we used the standard NASA SeaWiFS algorithm to estimate the chlorophyll_a distribution around the Korean waters using Orbview/ SeaWiFS satellite data acquired by our HPRT station at NFRDl. We studied In find out the relationship between the measured chlorophyll_a from the ship and the estimated chlorophyll_a from the SeaWiFs satellite data around the northern part of the East China Sea, in February, and May, 2000. The relationship between the measured chlorophyll_a and the SeaWiFS chlorophyll_a shows following the equations (1) In the northern part of the East China Sea. Chlorophyll_a =0.121Ln(X) + 0.504, R²= 0.73 (1) We also determined total suspended sediment mass (55) and compared it with SeaWiFS spectral band ratio. A suspended solid algorithm was composed of in-.situ data and the ratio (L/sub WN/(490 ㎚)L/sub WN/(555 ㎚) of the SeaWiFS wavelength bands. The relationship between the measured suspended solid and the SeaWiFS band ratio shows following the equation (2) in the northern part of the East China Sea. SS = -0.703 Ln(X) + 2.237, R²= 0.62 (2) In the near future, NFRDI will develop algorithms for quantifying the ocean color properties around the Korean waters, with the data from regular ocean observations using its own research vessels and from three satellites, KOMPSAT/OSMl, Terra/MODIS and Orbview/SeaWiFS.