• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.211-218
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• 2007

Even though some standard developmental bioassay protocols for environmental assessment using sea urchins have already been described, there have not been many attempts to apply and modify these protocols with Korean species. Therefore, there is a strong need to establish standard bioassay protocols using sea urchins commonly found in Korea. Prior to developing a new protocol, it is essential to know the optimal conditions for the bioassay procedures. We investigated the optimal conditions (temperature, salinity, and embryo density) of the sea urchin Strongylocentrotus intermedius. The ideal temperature for developmental bioassay of S. intermedius was determined to be $15^{\circ}C$ and the time required for the embryo to become pluteus larva was 72 hr. The optimal range of salinity for the embryo toxicity using S. intermedius was between 30 to 32 psu, which is similar to the range found in the natural habitats of adult populations. The optimum density of embryos at the beginning of bioassays was 100 embryos/mL. When the assays were carried out at higher densities, the proportion of normally developed larvae decreased significantly.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.1-8
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• 2010

Electronic Navigational Charts(ENCs) are a database for the use of supporting the safety of navigation in marie voyage embedded within the navigational information in the Electronic Chart Display & Information System(ECDIS). Recently IMO made a decision on the mandatory equipment resolution of ECDIS for the international SOLAS vessels until 2018. With this regulation intention together the spontaneous uses from the wide range of marine applications are accelerating the increasing demand for ENCs at both of the navigational purpose and the non-navigational purpose. But there seems to be not enough guidelines or systematic approach for the service of the non navigational purpose. This paper deals with ENCs distribution issues. We present a integrated solution for the ENCs service of both user domains and also demonstrate the implemented results.

• Ocean and Polar Research
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• v.28 no.4
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• pp.415-423
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• 2006

Interannual variation and long-term trends of coastal sea surface temperature (SST) in Korea were investigated by analyzing 27 coastal SST time series from 1969 to 2004. Long-term linear increasing trend was remarkable with the rate over $0.02^{\circ}C/year$ at almost all the stations. The slope of long-term linear trend was larger at the stations along the eastern coast than in the western and southern regions. It was also noticeable that there was a common tendency of interannual variability with the period of 3-5 years at most of the stations. SST was lower in the 1970's and early 1980's while it was higher in the 1990's and early 2000's after the increase in the late 1980's. The pattern of the interannual variability of SST was similar to that of air temperature. Increasing trend of minimum SST in winter was obvious at most stations na it was larger along the eastern coast, while the linear trend of maximum SST in summer was less definite. Therefore, the decreasing tendency of annual amplitude was mainly due to the increasing tendency of SST in winter.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.184-191
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• 2011

Preliminary design of a mooring system for a floating wave energy converter(WEC) is performed. A mooring line is designed to consist of two parts; the one is a chain in heavy weight laid on the seabed and linked to an anchor on the seabed and the other is a light weight chain suspended at a floater. A high weight chain laid on the seabed can contribute to mitigate dynamic energy propagated from top oscillation and decrease anchor weight and volume. Through a low weight chain suspended between a floater and seabed the WEC's function to produce energy from wave can be affected in minimum by the motion of a chain. The static and dynamic analyses for the designed mooring system were carried out to evaluate WEC system's safety. The present study shows that the designed gravity anchor moves horizontally due to the tension exerted on the anchor in the severe ocean environmental condition. The present mooring system should be redesigned to satisfy the safety requirements. The present study will be useful to predict the safety of the mooring system under ocean environment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.2
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• pp.170-178
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• 2007

Most of parabolic approximation models employ a relatively limited open boundary condition in which there is no depth variation in the longshore direction outside of the computation domain so that Snell's law may be presumed to hold. Existing Kirby's condition belongs to this category and in the paper both modified Kirby's method and Dirichlet boundary condition are presented in detail and numerical results of three methods were shown. Judging from computation to wave propagations over a circular shoal in a constant depth, the method based on present Dirichlet boundary condition with fictitious numerical adjusting regions in both sides of the computation domain gives the least distorted amplitude ratio distribution.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.4
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• pp.224-229
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• 2011

Recently, the management of the marine invasive alien species introduced by ballast water has come to the core as an urgent task. Because, hazardous organisms cause harmful effects on the ecosystem. Hazardous organisms also negatively affect fisheries, commercial shipping activities, and marine resources. In this regard, IMO used to operate GloBallast, Ballast Water Risk Assessment System, in order to manage the introduction of invasive species by ballast water. GloBallast is constructed to assess the relative risk due to the movement of ballast water between nations, using the volume and the number of times of ballast water discharge, the environmental similarity between ports, and the abundance of hazardous species as the main factors. According to the results of the demo-operation of GloBallast, it was found out that the environmental similarity factor had affected most highly the results of risk assessment. Therefore, in this study, the correlation between the main factors used in GloBallast risk assessment were re-examined, and some methods were suggested in order to reflect these main factors in the risk assessment more reasonable.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.1
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• pp.58-66
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• 2010

In this paper, we have constructed high-resolution topographical map of macro-tidal Malipo beach through integration of terrestrial LiDAR measurement and MBES survey data at inter-tidal zone. To acquire the enough information of inter-tidal zone, we have done terrestrial LiDAR measurement mounted on the roof of vehicle with DGPS through go-stop-scan method at the ebb tide and MBES depth surveying with tide gauge and eye staff measurement for tide correction and MSL calculation at the high tide all together. To integrate two kinds of data, we have unified the vertical coordination standard to Incheon MSL. The mean error of overlapped inter-tidal zone is about 2~6 cm. To verify the accuracy of terrestrial LiDAR, RTK-DGPS measurement have done simultaneously and the difference of Z value RMSE is about 4~7 cm. The resolution of Malipo topographical map is 50 cm and it has constructed to DEM (Digital Elevation Model) based on GIS. Now it has used as an input topography information for the storm-surge inundation prediction models. Also it will be possible to use monitoring of beach process through the long-term periodic measurement and GIS-based 3D spatial analysis calculating the erosion and deposition considering with the artificial beach transition and coastal environmental parameters.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.1
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• pp.30-34
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• 2004

To verify the characteristics of deep ocean water, oceanographic observation and qualitative analysis were carried out from March of 2001 to February of 2002. Spatiotemporal variation of water quality of deep ocean water were discussed from survey results around development site and along northeastern coastal sea of Korean peninsular. Vertical distribution of water temperature and salinity were measured, and sampled seawater were analyzed in order to determine the definition of deep ocean water resource and the position of intake device for supplying qualified deep ocean water resource.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.75-82
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• 2010

The economical efficiency and easy ship building have enabled to spread FRP ships in the shipbuilding field. As waste FRP ships have been thrown away at a river or within a harbour, this matter has become issues. For the improvement of this matter, the melting technique and system of waste FRP ships was developed. But, Decision making was required for a location plan of the melting system of waste FRP ships. It's recognized that the location decision of this system is difficult due to the dependence on technical, economical, environmental factors. In this paper, we survey the primary factors of location-economic, life-environment, infrastructure and make up a question for the experts. We also calculate the important weight and related weight using Fuzzy AHP, Limiting probability method and discuss on the calculation results on the proposed sites.

• Ocean and Polar Research
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• v.26 no.2
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• pp.145-154
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• 2004

Surface energy and $CO_2$ fluxes have been measured over an ocean at Ieodo Ocean Research Station of KORDI since May 2003. Eddy covariance technique, which is a direct flux measurement, is used to quantitatively understand the interaction between the ocean surface and the atmospheric boundary layer. Although fluxes were continuously measured during the period from May 2003 to February 2004, the quality control of these data yielded <20% of data retrieval. The atmospheric stability did not show any distinct dirunal patterns and remained near-neutral to stable from May to June but mostly unstable during fall and winter in 2003. Sensible heat flux showed a good correlation with the difference between the sea water temperature and the air temperature. The maximum fluxes of sensible heat and latent heat were $120Wm^{-2}$ and $350Wm^{-2}$ respectively, with an averaged Bowen ratio of 0.2. The ocean around the tower absorbed $CO_2$ from the atmosphere and the uptake rates showed seasonal variations. Based our preliminary results, the daytime $CO_2$ flux was steady with an average of $-0.1 mgCO_2m^{-2}s^{-1}$ in summer and increased in winter. The nighttime $CO_2$ uptake was greater and fluctuating, reaching up to $-0.1 mgCO_2m^{-2}s^{-1}$ but these data require further examination due to weak turbulent mixing at nighttime. The magnitude of $CO_2$ flux was positively correlated with the half hourly changes in horizontal mean wind speed. Due to the paucity of quality data, further data collection is needed for more detailed analyses and interpretation.