• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.293-307
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• 2020

Every year, the floating macroalgae, green and golden tide, are massively detected at the Yellow Sea and East China Sea. After influx of them to the aquaculture facility or beach, it occurs enormous economic losses to remove them. Currently, remote sensing is used effectively to detect the floating macroalgae flowed into the coast. But it has difficulties to detect the floating macroalgae exactly because of the wavelength overlapped with other targets in the ocean. Also, it is difficult to distinguish between green and golden tide because they have similar spectral characteristics. Therefore, we tried to distinguish between green and golden tide applying the Deep learning method to the satellite images. To determine the network, the optimal training conditions were searched to train the AlexNet. Also, Gaofen-1 WFV images were used as a dataset to train and validate the network. Under these conditions, the network was determined after training, and used to confirm the test data. As a result, the accuracy of test data is 88.89%, and it can be possible to distinguish between green and golden tide with precision of 66.67% and 100%, respectively. It is interpreted that the AlexNet can be pick up on the subtle differences between green and golden tide. Through this study, it is expected that the green and golden tide can be effectively classified from various objects in the ocean and distinguished each other.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.633-642
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• 1994

Distribution of ichthyoplankton in the adjacent waters to Kori were surveyed during the period from April, 1991 to January, 1992. The dominant fish eggs included the eggs of Engraulis japonica, Maurolicus muelleri, Callionymus spp. and others. The eggs of Engrualis japonica and Maurolicus muelleri were $79.52\%$ and $1.86\%$ of the total eggs abundance, respectively. A total of 15 taxa of fish larvae were found. The dominant species was Engraulis japonica accounting for $52.39\%$ of the total larvae and followed by Callionymidae fish($29.36\%$). Other major species were Stephanolepis cirrhifer($6.30\%$), Sebastes schlegeli($3.16\%$), Ammodytes personatus($1.33\%$) and Girella punctata($1.70\%$). These 6 taxa constituted $94.30\%$ of the total larvae collected. In this area, distributions of warm water had a great influence on larvae and juvenile distribution which usually is along the coast and the other places where there layer water movements since, upwelling in the open sea affects ichthyoplankton distribution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6388-6398
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• 2014

To understand size fractioned chlorophyll a and material cycle characteristics in Jeju marine ranching area (JMRA), 4 times of survey were conducted from April to November 2008. Picoplankton on the surface in JMRA was on average, $0.30{\mu}g/L$(annual mean(M):17.3%) in the $0.03{\sim}0.84{\mu}g/L$ range, accounting for 17.3%. Nannoplankton and picoplankton was on average, $1.35{\mu}g/L$(M:78.0%) in the $0.22{\sim}3.93{\mu}g/L$ range, and $1.73{\mu}g/L$(M:4.7%) in the nd ~ 0.24 range, respectively. The 10m layer was similar to the surface. The measured values changed according to the measurement times but the nanoplankton composition ratio was higher throughout the year. In addition, the size fractioned chlorophyll a distribution in JMRA was similar to that of tropical sea area affected by the Monsoon rather than South Korean offshore coast geographically adjacent to the East China Sea and Japan coastal waters affected by the Kuroshio/Tsushima warm currents. That is, the material cycle of JMRA consists of a microbial food web rather than traditional food chain at a lower trophic levels. Primary production is deemed to have a higher possibility of being adjusted by top-down dynamics, such as micro-zooplankton grazing pressure rather than nutrients supply.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.496-505
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• 2020

In the previous research, the effectiveness of resonator was confirmed through the numerical analysis on two cases with the use of existing resonator at the Mukho and Imwon ports located in the eastern coast of South Korea by discussing the reduction rates of 1983 Central East Sea tsunami, and 1993 Hokkaido Southwest off tsunami, respectively. In this study, the reduction rates of tsunami height with three different resonators, Type I, II-1, and II-2, at the Samcheok port were examined respectively through the numerical analysis using COMCOT model under the same condition as the previous study. It was discussed the spatial distribution of maximum height of tsunami, change of water level, and effectiveness of resonator with the presence of new types of resonator, and change of their sizes. As a result, the effectiveness of resonator was verified through the application of new types of resonator reducing about maximum 40% of tsunami height. In order to design the optimal resonator for the variety of site condition, it is necessary to research about the various cases applying different shape, arrangement, and size of resonator as further study.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.58-63
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• 2020

The ascidian Halocynthia aurantium (sea peach), which belongs to the phylum Chordata, is thought to be a valuable organism of aquaculture like H. roretzi (sea pineapple), but its biological characteristics such as development and ecology are not well known. In this study, in order to obtain basic data for H. aurantium farming, the development processes of H. aurantium inhabiting the east coast of Gangwon-do were investigated and compared with those of H. roretzi, a related species. As a result, the morphology and developmental stages of the fertilized eggs, embryos and larvae of H. aurantium were very similar to those of H. roretzi. Fertilized eggs of H. aurantium took about 42.1 hours to hatch at 11℃, almost similar to 40.9 hours of H. roretzi. The time required for larvae to metamorphose into juveniles after hatching was very similar between the two species. The hatched larvae of the two species became juveniles with oral and atrial siphons after 23 days at 11℃. Both types of embryos developed slowly in seawater at low temperatures and rapidly developed at high temperatures. Fertilized eggs of H. aurantium hatched in an average of 62.3 hours at 9℃, 42.1 hours at 11℃, and 36.3 hours at 13℃, whereas those of H. roretzi hatched in an average of 60.4 hours, 40.9 hours, and 35.2 hours. Most of H. aurantium embryos did not develop normally above 15℃, so it is thought that attention is needed in the seed production processes.

• (The) Research of the performance art and culture
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• no.41
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• pp.321-352
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• 2020

Donghaean Byeolsingut itself reflects the ideals and dreams of seaside life. Imagination and interest in water are fully reflected in Donghaean Byeolsingut as a living in a seaside town. For the beach people, water is the foundation of life and the object of fear. It is the water of life and the water of death. It projects the whole process of life into the imagination created by the world encompassed by the sea. The beach's imagination is an existential insight into the whole process of life and a reflection of existential agony. At Poongeoje, the villagers hope for a specific blessing from God. People are free only when God's retribution comes down. The villagers feel free because of the virtue of the shaman's blessing. Individual trauma is experienced to a certain extent by gaining mental freedom. It can be said that the state of aesthetic pleasure experienced by creating an art work by itself and the nature of aesthetic pleasure experienced through Pungeoje and Byeolsingut are not different. The prototype of Poongeoje is a free spirit, and a religious aesthetic to strengthen the free spirit is the core of the aesthetic.

• Journal of the Korean earth science society
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• v.21 no.3
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• pp.230-249
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• 2000

Southeastern Korean Peninsula has undergone the polyphase deformations according to the changes of regional tectonic settings during the Cenozoic. Through analyses of more than 600 fault-slip data gathered in the study area, five tectonic events are revealed as the followings: (I) NW-SE transtension, (II) NW-SE transpression, (III) NE-SW pure or radial extension, (IV) NNE-SSW transpression, (V) NE or ENE-WSW transpression. Event I was induced by the pull-apart type extension of the East Sea during 24-16 Ma, which resulted in the NW-SE extension of the Tertiary Basins in SE Korea. Event II was resulted from the collision of SW Japan and Izu-Bonnin Arc (or Kuroshio Paleoland) on the Philippine Sea Plate at ${\sim}$ 15 Ma, which stopped the extension of the Tertiary Basins and originated the uplift of fault blocks in and around SE Korean Peninsula. It was continued until ${\sim}$ 10 Ma. Event III is interpreted as the post-tectonic event after the block-uplifts due to the event II, which indicates a temporal lull in activity of the Philippine Sea Plate since 10 Ma. Event IV was originated from the resumption in activity of the Philippine Sea Plate which was restarted to move toward north at ${\sim}$ 6 Ma. The event made the EW compressional structures behind SW Japan as well as in the Korea Straits, and thus the block-uplifts in SE Korea was resumed again. Lastly, event V was resulted from the gradual decrease in influence of the Philippine Sea Plate and the cooperative compression due to the subduction of the Pacific Sea Plate and the collision of the Indian Plate since 5-3.5 Ma, which generated the NS compressional structures in the offshore along the eastern coast of the Korean Peninsula and thrust up the fault-blocks toward west. This event is continuing so far, and thus is making the active faultings resulting in the present earthquakes of the Korean Peninsula.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.2
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• pp.119-130
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• 2000

Mn, Zn, Cd and Pb in shells of Littorina brevicula, which lives ubiquitously in intertidal zone around the Korean coast, were analyzed to determine the relationship between metal levels in its shell, ambient seawater and its tissue. Periwinkles and seawater samples were collected from 38 sites along the Korean coast in January 1997. Mn contents in shells of this organism show the range of 7.0 ${\mu}g$/g-211 ${\mu}g$/g (mean 59 ${\mu}g$/g) and are the lowest in northern east coast but high in western south and west coast. Close relationship between Mn contents in shells and metal levels both in seawater and in tissues indicates that Mn in shell might be incorporated from ambient seawater by a biological process. Although the contents of Cd in shells did not reflect the distribution of total Cd in seawaters and they were very low compared to those in tissues, they followed spatial gradient of contents in tissues. However, the spatial distribution of Zn contents in shells accords neither ambient seawater nor tissues, while it is negatively correlated with the contents of Na in shells. This fact suggests that Zn contents might be controlled by salinity of ambient seawater. On the contrary, Zn contents in highly polluted sites near Onsan Bay show generally higher levels than other sites. The contents of Pb show the range of 0.1 ${\mu}g$/g-17.5 ${\mu}g$/g (mean 1.01 ${\mu}g$/g) and the highest in sites near Onsan Bay. Although the spatial distribution of shell Pb does not follow those of tissue, Pb in shells of Littorina brevicula may be controlled both by shell secretion process and by Pb levels in ambient seawater because the contents of Pb in the shell decrease steadily with growth and vary with levels of Pb in ambient seawater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.4
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• pp.206-216
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• 2017

The temporal distribution of the turbulence kinetic energy (TKE) and the vertical component of Reynolds stresses ($-{\bar{u^{\prime}w^{\prime}}}$) was measured during one wave period under high wave energy conditions. The wave data were obtained at Hujeong Beach in the east coast of Korea at January 14~18 of 2017 when an extratropical cyclone was developed in the East Sea. Among the whole thousands of waves measured during the period, hundreds of regular waves that had with similar pattern were selected for the analysis in order to give three representing mean wave patterns using the ensemble average technique. The turbulence properties were then estimated based on the selected wave data. It is interesting to find out that $-{\bar{u^{\prime}w^{\prime}}}$ has one clear peak near the time of flow reversal while TKE has two peaks at the corresponding times of maximum cross-shore velocity magnitudes. The distinguished pattern of Reynolds stress indicates that vertical fluxes of such properties as suspended sediments may be enhanced at the time when the horizontal flow direction is reversed to disturb the flows, supporting the turbulence convection process proposed by Nielsen (1992). The characteristic patterns of turbulence properties are examined using the CADMAS-SURF Reynolds-Averaged Navier-Stokes (RANS) model. Although the model can reasonably simulate the distribution of TKE pattern, it fails to produce the $-{\bar{u^{\prime}w^{\prime}}}$ peak at the time of flow reversal, which indicates that the application of RANS model is limited in the prediction of some turbulence properties such as Reynolds stresses.

• Journal of the Korean earth science society
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• v.36 no.1
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• pp.68-81
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• 2015

In this study, the correlation between the frequency of summer tropical cyclones (TC) affecting areas around Korea over the last 37 years and the western North Pacific monsoon index (WNPMI) was analyzed. A clear positive correlation existed between the two variables, and this high positive correlation remained unchanged even when excluding El Ni$\tilde{n}$o-Southern Oscillation (ENSO) years. To investigate the causes of the positive correlation between these two variables, ENSO years were excluded, after which the 8 years with the highest WNPMI (positive WNPMI phase) and the 8 years with the lowest WNPMI (negative WNPMI phase) were selected, and the average difference between the two phases was analyzed. In the positive WNPMI phase, TCs usually occurred in the eastern waters of the tropical and subtropical western North Pacific, and tended to pass the East China Sea on their way north toward Korea and Japan. In the negative WNPMI phase, TCs usually occurred in the western waters of the tropical and subtropical western North Pacific, and tended to pass the South China Sea on their way west toward the southeastern Chinese coast and the Indochina peninsula. Therefore, TC intensity was higher in the positive WNPMI phase, during which TCs are able to gain sufficient energy from the sea while moving a long distance to areas nearby Korea. TCs also tended to occur more often in the positive WNPMI phase. In the difference between the two phases regarding 850 and 500 hPa streamline, anomalous cyclones were reinforced in the tropical and subtropical western North Pacific, while anomalous anticyclones were reinforced in mid-latitude East Asian areas. Due to these two anomalous pressure systems, anomalous southeasterlies developed in areas near Korea, with these anomalous southeasterlies playing the role of anomalous steering flows making the TCs head toward areas near Korea. Also, due to the anomalous cyclones developed in the tropical and subtropical western North Pacific, more TCs could occur in the positive WNPMI phase.