• Journal of Korean Port Research
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• v.12 no.1
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• pp.95-104
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• 1998

Water pollution in a semi-enclosed sea area such as a bay due to stagnancy of water has been a serious water environmental problem. Recently, some kinds of new methods to activate the tidal exchange between an inner bay and an outer sea area by control of a tidal residual current have been proposed. However, these methods have several problems, that is, I). deterioration in a natural view due to building of huge structures, II). increase of risk of navigation in case of a submerged structure, III). limition of sea area where a tidal current can be controlled and IV). difficulty in removing those structures in case of occurrence of an unexpected impact on water environment. In this paper, a new method is proposed, which can solve all the above problems, to purify water quality in a semi-enclosed bay by creation and control of a pattern of a tidal residual current. The tidal residual current is controlled by unsymmetric structures, which change the properties of resistance according to the direction of flow, arranged on the sea bottom. In this study, several numerical and hydraulic experiments of tidal current and particle-tracking for various arrangements of bottom roughness in a semi-enclosed model bay were carried out. As a result of experiments, it becomes clear that it is possible to generate a new tidal residual current and to activate a tidal exchange by only operation of bottom roughness arrangement.

• Agribusiness and Information Management
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• v.9 no.1
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• pp.18-22
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• 2017

It takes lots of time and labor if a worker have to measure the water quality at a certain but designated time every day in an un-automated aqua farm. In addition, if the equipment is soaked in the sea water consistently, it will be contaminated by diverse floating matters and barnacles, and it often becomes mal-functional within 2~3 months. Therefore, we need to develop a system with which the sensed data could be checked in real time and operated automatically, while preventing the contamination of the sensor, a crucial component for water quality measuring equipment, as much as possible, and increasing the replacement cycle. We have developed a non-cleaning water quality measuring equipment and its software which are used in the fishery household of offshore aqua farms. By providing the workers with a mobile application which has a function of monitoring the water quality in real time, they can check the situation directly without going to the fishery household.

• Ocean and Polar Research
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• v.33 no.3
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• pp.291-301
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• 2011

To investigate major factors controlling variations in water quality, principal component analysis and cluster analysis were used to analyze data sets of 12 parameters measured at 23 sampling stations of Jinhae Bay during winter and spring. Principal component analysis extracted three major factors controlling variations of water quality during winter and spring. In winter, major factors included freshwater input, polluted material input, and biological activity. Whereas in spring they were polluted material input, freshwater input, and suspended material input. The most distinct difference in the controlling factors between winter and spring was that the freshwater input was more important than the polluted material input in winter, but the polluted material input was more important than the freshwater input in spring. Cluster analysis grouped 23 sampling stations into four clusters in winter and five clusters in spring respectively. In winter, the four clusters were A (station 5), B (stations 1, 2), C (station 4), and D (the remaining stations). In spring, the five clusters included A (station 5), B (station 1), C (station 3), D (station 6), and E (the remaining stations). Intensive management of the water quality of Masan and Hangam bays could improve the water quality of Jinhae Bay since the polluted materials were mainly introduced into Jinhae Bay through Masan and Hangam bays.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.321-337
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• 2010

Long-term trends and distribution patterns of water quality were investigated in the Mokpo coastal areas of the Yellow Sea, Korea from 1979 to 2009. Water samples were collected at 5 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO) and nutrients. Spatial distribution patterns of temperature, pH and DO were not clear among stations but the seasonal variations were distinct except ammonium. The trend analysis by principal component analysis (PCA) during 30 years revealed the significant variations in water quality in the study area. Spatial water qualities were discriminated into 3 clusters by PCA; station cluster 1, 2~4, and 5. Annual water qualities were clearly discriminated into 4 surface water clusters and 2 bottom water clusters by PCA. By this multi-variate analysis, the annual trends were summarized as the followings; water temperature, pH and COD tended to increase from late 1980's, salinity to decrease, phosphate to increase from 1994 and dissolved inorganic nitrogen to increase, due to the input of fresh water same as shown in Kyoungin coastal area, Asan coastal area, Choensoo bay and Gunsan coastal area.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.1
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• pp.33-39
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• 1999

A two-dimensional numerical experiment and field observations were conducted to evaluate changes in sea water movement and the water quality environment related to comprehensive projects of waterfront development around Kwangyang Bay on the south coast of Korea. Tidal flow velocities, especially in the western part of the bay, were considerably slower as a result of the development projects. Accordingly, the seawater exchange ratio reduced from 38.7% to 26.3%. The impact of dredging work on the water quality environment was much stronger than expected. Furthermore, after the completion of the industrial parks and container-exclusive wharfs, COD from the waste water treatment plant will be dispersed extensively into the adjacent water at a level of less than 0.1 mg/l for up to 142.5 $\textrm{km}^2$. Therefore, consistent monitoring and management of the water quality environment is strongly recommended.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1239-1241
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• 2003

This paper presents the results of Landsat-TM imagery applications for detecting spatial variations of the water environments in the Saemankeum (STLR) project areas. The simulated tidal flow patterns from a two -dimensional hydro - dynamic model and water quality data from STRL project were used for relationships with the satellite data. Unsupervised classification of the tidal water body reflects the overall flow patterns at a flooding tide. Regressive equations for water quality parameters were derived and used for supervised classifications. The results were found to be useful to synoptically evaluate the water environments during the construction stages of the STLR project.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.716-721
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• 2012

This study was designed to compare the quality characteristics of spray-dried (SD) and freeze-dried (FD) powders prepared with hot water extracts of sea mustard (Undraia pinnatifada) and sea tangle (Laminaria longissima). The moisture content of FD seawed was lower than that of SD, and sea mustard had a higher overall moisture content than sea tangle. The alginic acid content of SD seaweed was significantly higher than that of FD seaweed for both species. There were relatively higher contents of phenolic compounds in SD powders than in FD powders. DPPH radical scavenging ability was significantly greater in SD seaweed, and also, SOD-like activity in SD powders was higher than those of FD powders. However, the nitrite scavenging activity of FD powders of sea mustard (10 mg/mL) was higher than that of SD. In conclusion, spray-dried sea mustard and sea tangle extracts exhibited higher physiological functionalities than their freeze-dried counterparts.

• Journal of Environmental Science International
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• v.7 no.5
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• pp.591-598
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• 1998

This study was conducted to evaluate water quality in the Keum River estuary using principal component analysis. The results was summarized as follow; Water quality in the Keum River estuary could be explained up to 70.40% by three factors which were included in the inffluent loading by the Keum River and Kyungpo cheon(38.99%), seasonal variation and organic matter pollution(19.05%), sediment resuspension and internal metabolism(12.35%). For spatial variation of factor score, artificial pollutant loading is highest at st.1, below Keum River barrage, and decreases toward the outer sea. For annual variation of factor score, factor 1 was highly related to artificial pollutant leading, and it was gently increased in 1994. Also, organic matter pollution, sediment resuspension and internal metabolism were increased to every year. It is necessary to control the nutrient leading by Keum river and Kyongpo cheon for Water quality management of estuary.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.425-435
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• 2019

Purpose: The purpose of this study was to resolve the Naval ship's Local Operation Panel(LOP) malfunction problems which caused by overheating in summer season and dispatching to equatorial regions. Methods: Instead of using dual type heat insulation materials(consist with ceramic wool and glass wool), aerogel heat insulation materials were used for decreasing heat emissions from gas-turbine heat waste steam pipes passing water-jet- room. Experiment and Computational analysis of heat flow were conducted to analyze the internal room temperature changes. Results: The results of this study are as follows; The aerogel heat insulation materials suppress heat emission more efficiently than dual type insulation materials. The cold surface temperature of insulation was far more decreased and internal room, LOP surface temperature also showed significant results too. Conclusion: The substituted heat insulation materials appeared remarkable performance in decreasing room temperature that it could be used for suppressing the LOP overheatings and malfunctions.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.141-151
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• 2009

Temperature, salinity, COD, DIN (Dissolved Inorganic Nitrogen), DIP (Dissolved Inorganic Phosphorus), and Chlorophyll ${\alpha}$ obtained from the southern coastal waters during the period of 2003 to 2005 were analyzed. Variability in temperature was not found between groups in southern coastal waters, but significantly different depending on sampling sites (p<0.05). The average temperature in 2003 estimated at $18.33^{\circ}C$ that was annually increased by 2005 and significantly different based on statistics (p<0.05). Unlikely to temperature, salinity was significantly different depending on sampling sites, as well as monthly variations (p<0.05). Likewise to temperature, the value of salinity was annually increased. COD estimated at the average of $>1.7\;mg\;l^{-1}$ for three years, indicating optimal water quality. The fluctuations of nutrients were extremely shown in different sampling sites and monthly variations. Chlorophyll a recorded above $2.0{\mu}g\;l^{-1}$ which was associated with high primary phytoplankton, whereas it showed much fluctuations in temporal and spatial, In particular, Tongyong, Jaranman, Jinjuman, and Samcheonpo located in the southeast were the highest fluctuations in water quality than any other regions. The correlation between salinity/COD and nutrients/chlorophyll a was strongly negative or positive, which was possibly associated with much the introduction of run-off water as well as rainfall in summer.