• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1241-1244
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• 2005

In this case study, the field investigation work on soft soils like a reclamation area with dredged-clay or intertidal mud flat which has not enough strength to resist the load of surveying machines, the amphibious barge(modified AMFIROL) which travels on land and water was adopted to the field investigation work. Despite of slight increase of cost, it was found that the adoption of amphibious barge in field investigation could improve the quality of test results and avoid the waste of time and some effort.

• Journal of Environmental Science International
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• v.31 no.12
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• pp.1027-1038
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• 2022

The intertidal zone has both land and marine characteristics and shows complex weather environments. These characteristics are suited for studying climate change, energy balance and ecosystems, and may play an important role in coastal and marine weather prediction and analysis. This study was conducted at Odo Island, approximately 300m from the mainland in Yeosu. We built a weather observation system capable of real-time monitoring on the mud flat in the intertidal zone and measured actual weather and marine data. Weather observation was conducted from April to June 2022. The results showed changes in air temperature and water temperature with changes in the tide level during spring. Correlation analysis revealed characteristic changes in air temperature and water temperature during the day and night, and with inundation and exposure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.44-50
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• 2004

Age and growth of the blue spot mudskipper (Boleophthalmus pectinirostris) were studied using the samples caught in the mud flats of southwestern Korea during April-October, 2001. The value of the marginal index of the second actinost bone was the lowest in July and October and indicated by rings that was analysis of formed teice a year. The relationship between body weigt (BW) and total length (TL) was expressed as BW=0.000005 $TL^{3.12}\;(r^2=0.92)$ for females and BW=0.000476 $TL=^{2.18}\;(r^2=0.62)$ for males. Regression analysis of TL-BW between sexes showed a significant difference (P<0.01). Relationship between total length (TL) and actinost radius (R) were expressed as TL=16.9+33.4 R $(r^2=0.62)$ for females and TL=45.8+26.2 R $(r^2=0.41)$ for males. Growth parameters, $L\infty,t_0$ and K were estimated as 165.2 mm, -0.23, and 1.07 for females and 155.3 mm, -0.35, and 1.39 for males.

• The Korean Journal of Food And Nutrition
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• v.19 no.4
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• pp.496-501
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• 2006

This study was to isolate a bacterium producing a alkaline protease from mud flats of the west seaside of Korea and to investigate the biochemical analysis of the alkaline protease producing from the isolate. The isolate was named as Gelidibacter sp. HK-1 based on 16S rRNA sequence, Gram staining and the photograph of electron microsceope. Optimum temperature for growth and pretense production of the isolate was $25^{\circ}C$. Growth of the isolate was reached at stationary phase after 10hrs followed by inoculation. Maximum activity of protease produced from the isolate was shown after 14hrs. Optimum temperature and pH for the protease activity were $45^{\circ}C$ and pH 9, respectively. Molecular weight of the pretense was about 50KD and the partial amino acid sequence of the pretense was Ala-Try-Ala-Leu-Asn-Thr-Ser-Val-Thr-Glu-Thr-Phe-Ala-Lys. The partial amino acid sequences of the protease showed significant homology with a pretense produced from Streptomyces avermitilis.

• The Korean Journal of Food And Nutrition
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• v.22 no.1
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• pp.14-19
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• 2009

This study was performed to characterize the lipases produced from Gelidibacter sp. YH333 and Vibrio sp. YH339 isolated from mud flats for industrial application of a lipase. Amount of the lipases secreted from the isolated strains was sharply increased in the proportion of increase of number of the cells. The lipases produced from the isolated strains were constitutively secreted from the cells. The lipase activity of Gelidibacter sp. YH333 was higher than that of Vibrio sp. YH339 to p-nitrophenyl esters. The lipases produced from both strains showed the highest activity in p-nitrophenyl laulate among various p-nitrophenyl esters. The molecular weights of the lipases from Gelidibacter sp. YH333 were about 50 KDa and 25 KDa, respectively. Molecular weight of the lipase from Vibrio sp. YH339 was about 50 KDa.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.2
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• pp.135-141
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• 2018

This study investigated the immuno-potentiating activities of Japanese mud shrimp Upogebia major. We examined the effects of enzymatic hydrolysate from U. major on the production of nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) and on the expression of pro-inflammation cytokines including $TNF-{\alpha}$, IL-6 and $IL-1{\beta}$ in RAW 264.7 cells. The treatment of six enzymatic hydrolysates of U. major (alcalase, ${\alpha}$-chymotrypsin [${\alpha}-Chy$], trypsin, pepsin, neutrase, protamex) significantly increased the production of NO in RAW 264.7 cells, with ${\alpha}-Chy$ having the greatest effect. This hydrolysate was fractionated by two ultrafiltration membranes at 3 and 10 kDa to created three fractions (below 3 kDa, between 3 and 10 kDa, and above 10 kDa). Of these, the <3 kDa and >10 kDa fractions showed significant increases in NO production. These two fractions also induced $PGE_2$ production in RAW 264.7 cells and showed significant increases in the expression of all cytokines studied. These results suggest that enzymatic hydrolysate from U. major is a potentially useful food material with immune-potentiating effects.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.49-58
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• 2006

This study was conducted to evaluate effects of mud flat bacteria origin protease supplementation on growth performance, amino acid digestibility, blood characteristics, meat quality, fecal VFA (volatile fatty acids) and NH3-N (ammonia nitrogen) concentration in finishing pigs. Eighty pigs (Landrace×Yorkshire×Duroc, 60.08±2.69 kg average initial body weight) were used during experimental period. Dietary treatments included 1) high nutrient density diet, 2) high nutrient density diet+0.1% protease, 3) low nutrient density diet and 4) low nutrient density diet+0.1% protease. For overall period, ADG was improved in treatment of high nutrient density diet added protease compared with treatment of low nutrient density diet without protease (P<0.05). DM and N digestibilities were improved in treatments of high nutrient density diet and low nutrient density diet added protease compared with treatment of low nutrient density diet without protease (P<0.05). Essential amino acid digestibility was improved in treatment of low nutrient density diet added protease compared with other treatments (P<0.05). Nonessential amino acid digestibility was improved in treatment of high nutrient density diet added protease compared with treatments of high and low nutrient density diet (P<0.05). BUN (blood urea nitrogen)　concentration in blood was increased in treatment of high nutrient density diet added protease compared with treatment of low nutrient density diet without protease (P<0.05). L*value of M. longissimus dorsi muscle was increased in treatments of low nutrient density diet compared with treatments of high nutrient density diet (P<0.05). In conclusion, mud flat bacteria origin protease was effective for improving growth performance, amino acid digestibility and influencing BUN concentration and meat color in finishing pigs.

• Journal of the Korean Geographical Society
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• v.36 no.4
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• pp.474-482
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• 2001

The purpose of this study is to investigate the formation and development processes of beach resort by fabric construction in a island environment. The results are as follows. (1) The research area(Tong-ri beach, Bokil-myon, Chollanam-do)has been transformed to belch by sedimentary environmental change since latter half of 1800's. (2) The mean slope of beach face is 0.96°, and the difference of attitude between beach and mud flat face is 75cm. (3) The mean particle size of beach surface sediment is 3.53$\Phi$. This value is very finer than that of any other beach in Korea peninsula. But its value is coarser than that of mud flat surface sediment. (4) The particle size distribution of core sediment is become changed to fine particle in 70cm depth. This value is corresponded to difference of altitude between beach face and mud flat face. (5) The analysis of aerial photographs after 1970 indicates that sedimentation process was not brisked since 1970's. Consequently, the research ares has been developed by sedimentary environmental change for sea-level rise effect and wave height energy rise effect.

• Korean Journal of Remote Sensing
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• v.40 no.3
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• pp.295-305
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• 2024

This study aims to analyze the micro-sedimentary structures of the Hwangdo tidal flats using ultra-high resolution unmanned aerial vehicle (UAV) data. Tidal flats, located in the transitional area between land and sea, constantly change due to tidal activities and provide a unique environment important for understanding sedimentary processes and environmental conditions. Traditional field observation methods are limited in spatial and temporal coverage, and existing satellite imagery does not provide sufficient resolution to study micro-sedimentary structures. To overcome these limitations, high-resolution images of the Hwangdo tidal flats in Chungcheongnam-do were acquired using UAVs. This area has experienced significant changes in its sedimentary environment due to coastal development projects such as sea wall construction. From May 17 to 18, 2022, sediment samples were collected from 91 points during field surveys and 25 in-situ points were intensively analyzed. UAV data with a spatial resolution of approximately 0.9 mm allowed identifying and extracting parameters related to micro-sedimentary structures. For mud cracks, the length of the major axis of the polygons was extracted, and the wavelength and ripple symmetry index were extracted for ripple marks. The results of the study showed that in areas with mud content above 80%, mud cracks formed at an average major axis length of 37.3 cm. In regions with sand content above 60%, ripples with an average wavelength of 8 cm and a ripple symmetry index of 2.0 were formed. This study demonstrated that micro-sedimentary structures of tidal flats can be effectively analyzed using ultra-high resolution UAV data without field surveys. This highlights the potential of UAV technology as an important tool in environmental monitoring and coastal management and shows its usefulness in the study of sedimentary structures. In addition, the results of this study are expected to serve as baseline data for more accurate sedimentary facies classification.

• Journal of Environmental Impact Assessment
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• v.24 no.3
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• pp.287-299
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• 2015

If the Nakdong River estuary is to be sustainable, land use management practices need to consider bird habitat requirements, especially given that the area serves as an important migratory bird sanctuary. In this study, bird habitats found in the Nakdong River estuary were classified into 11 different types including Phragmites australiss, mud flat, farmland, open surface in freshwater, sand bar, riparian forest, Scirpus planiculmis, waterway, construction, grasslands, and open surface in sea or brackish water. Taking into consideration the regional characteristics, habitat properties, and landscape indices, a total of 12 study sites were analyzed. Mud flat, construction, farmland, and P. australis account for 80% of the total land area. The high area ratio of construction and farmland to other types of habitat revealed a high amount of historical human activity and intervention in the area. Both patch numbers as well as patch density were high in West Nakdong River, Samrak Waterfront, Maekdo River, and Daejeo Floodgate, with these areas showing the greatest fragmentation as well. Total numbers of species and individuals had a positive correlation with the area and the number of habitat types. Findings suggest that protecting the habitat area, especially in S. planiculmis, is the most important factor for bird habitat management and that future development could result in habitat loss, having a profoundly adverse impact on bird populations. Therefore, it is important that the total area should be carefully protected by land use regulations in order to ensure that the Nakdong River estuary maintains its functional integrity as a migratory bird sanctuary.