• Geophysics and Geophysical Exploration
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• v.20 no.4
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• pp.241-267
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• 2017

Since the liberation in 1945, Korean specialists in the field of geological science and mineral resources engineering have developed two disciplines through the cooperation and competition with each other. Specialists both in the geophysics and in the geophysical exploration, who share much, have developed their own fields deeper and broader. Since the late 1990s, specialists in both fields felt the need for an independent society to deal with their fields and discussed the establishment of such a society. In 1997, they discussed to establish a unified society which integrates both fields instead of separated societies. However, in 1998, the Korean Geophysical Society and the Korean Society of Exploration Geophysicists were separately established due to some practical problems. During 7 ~ 8 years since the establishment of the two societies, many members of the two societies intended that the two societies should integrate into a single comprehensive society based on the facts that many fields of each society are overlapped and naturally many members of one society are the members of the other society. The leaders of the two societies accepted these opinions also and began to discuss thoroughly the integration from 2005. Eventually, in 2007, the two societies successfully integrated and established the Korean Society of Earth and Exploration Geophysicists. The Korean Society of Earth and Exploration Geophysicists continues to cooperate and compete with other societies of geological science and mineral resources engineering in Korea and in circumpacific area including Asia, Oceania and Americas, contributing to the development of geophysics and geophysical exploration.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.281-286
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• 2011

This study was performed to investigate the effects of salted and fermented shrimp ethanol extract (SFS) on serum lipid metabolism and hepatocytes in rats. Male Sprague-Dawley rats were administered 60% fat feed to induce hypercholesterolemia and were divided into five groups. Experimental groups were classified according to administered diet: normal diet group (NC), high cholesterol diet group (HC), high cholesterol and low dose shrimp extract (20 mg/kg) group (HC-SFSL), high cholesterol and high dose shrimp extract (200 mg/kg) group (HC-SFSH), and high cholesterol and lovastatin (20 mg/kg) group (HC-Lov). The experimental diets were fed ad libitum for 14 days. Compared with the control group, the serum cholesterol and triglycerides were 40.4 and 64.7% lower in the group fed HC-SFSH respectively. Low density lipoprotein (LDL)-cholesterol concentration in serum decreased in the HC-SFSH group compared with the HC group. In a histological assay, hepatocytes in the HC group showed that the vacuolated cells by fat appear clear due to the large amount of intracytoplasmic fat, whereas the liver hepatocytes in the group fed SFS effectively decreased fatty liver and intracytoplasmic fats. These results suggest that the extract of salted and fermented shrimp has an antiatherosclerotic effect and may lessen the effects of cardiovascular disease by reducing the cholesterol level in serum.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.3
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• pp.162-168
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• 2017

Shallow-water bathymetry survey has been conducted using high definition color images obtained at the altitude of 100 m above sea level using a drone. Shallow-water bathymetry data are one of the most important input data for the research of beach erosion problems. Especially, accurate bathymetry data within closure depth are critically important, because most of the interesting phenomena occur in the surf zone. However, it is extremely difficult to obtain accurate bathymetry data due to wave-induced currents and breaking waves in this region. Therefore, optical remote sensing technique using a small drone is considered to be attractive alternative. This paper presents the potential utilization of image processing algorithms using multi-variable linear regression applied to red, green, blue and grey band images for estimating shallow water depth using a drone with HD camera. Optical remote sensing analysis conducted at Wolpo beach showed promising results. Estimated water depths within 5 m showed correlation coefficient of 0.99 and maximum error of 0.2 m compared with water depth surveyed through manual as well as ship-board echo-sounder measurements.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.551-557
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• 1998

Whole soybean cereal was fermented with four Aspergillus strains in pilot meju fermentation system. The pH range of the product was 7.40~7.98, the contents of reducing sugar and amino-nitrogen were 0.04~2.78%, 178~309 mg%, respectively and that of free fatty acid ranged 2.67~5.05%. The components of the amino acid, organic acid, free sugars and fatty acid showed distinctive patterns among four groups of fermented soybean cereals. Amylase activity and carbohydrate degradation rate of A. usami was higher than other strains. But protease and protein degradation rate, lipase and lipid degradation rate were similar in four strains. The odor concentrates of soybean cereals fermented with Aspergillus strains were different from Bacillus strains. Especially, pyrazine components, the main and common flavor chemicals in Bacillus strains, were not determined in this study and Aspergillus specific components were 9-methyl-acridine, dl-limonene and 2,3-butanediol. Soybean paste, made from A. oryzae fermented soybean cereal, showed excellent sensory evaluation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.470-479
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• 2009

The local scour in waves can be thought of as very complex synthetic processes which is influenced by geology of bed material, bed flow in the sea and hydraulics condition. The most research until now be targeted at the scour depth and therefore the local scour width in waves has not been investigated as well. The size of wave or bottom velocity at the bed is direct cause of the local scour among lots of the scour effect factors, and the scour depth and width can be estimated through interrelationship analysis with scour area to use the dimensionless parameters including these such as Keulegan-Carpenter number, Ursell number etc. In this paper, to find out closely relation with the dimensionless parameters and scour width, performed an experiment with the variations of pipe diameters, wave heights and wave periods and then analyzed it. As the result, while Reynolds number and period parameter were seen to disperse local scour width largely, Shields number, KC number and Ursell number appeared good interrelationship. Specially, Shields number doesn't much affect the scour depth but has good relation for the scour width.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.26-37
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• 2006

This study addresses the applicability of box fractal dimension, $D_B$, as an index of statistical homogeneity of fractured rock mass. The box-count method's capability in quantifying the combined effect of fracture density and size distribution is examined systematically. Total of 129 two-dimensional fracture configurations were generated based on different combinations of fracture size distribution and fracture density. $D_B$was calculated for the generated fracture network systems using the box-counting method. It was found that was standard deviation of trace length and fracture orientation have no effect on calculated $D_B$. The estimated $D_B$ was found to increase with increasing total density and/or mean trace length. To explore the field applicability of this study, the statistical homogeneity of fractured rock mass was investigated at the rock slope and the underground facility using the box-counting method as well as conventional contingency table analysis. The results obtained in this study clearly show that the methodologies given in this paper have the capability of determining the statistical homogeneity of fractured rock mass.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.557-562
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• 2016

Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis are gram-negative bacteria frequently found in lesions from patients with periodontitis manifesting alveolar bone loss. Lipopolysaccharides are a major virulence factor of gram-negative bacteria. Bone resorption is known to be regulated by bacteria and their virulence factors. In the present study, we investigated the effects of A. actinomycetemcomitans and P. gingivalis on bone resorption. Heat-killed A. actinomycetemcomitans (HKAa) and heatkilled P. gingivalis (HKPg) induced bone loss in the femurs of mice after intraperitoneal administration. HKAa and HKPg augmented the differentiation of committed osteoclast precursors into osteoclasts, while they inhibited the differentiation of bone marrow-derived macrophages into osteoclasts. Concordant with the effects of the heat-killed whole cells, LPS purified from A. actinomycetemcomitans and P. gingivalis also augmented osteoclast differentiation from committed osteoclast precursors but attenuated it from bone marrow-derived macrophages. Taken together, these results suggest that the whole cells and lipopolysaccharides of A. actinomycetemcomitans and P. gingivalis induce the differentiation of committed osteoclast precursors into osteoclasts, potentially contributing to bone resorption in vivo.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.207-214
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• 2013

A concerted effort to develop alternative forms of energy is underway due to fossil fuel shortages and its deleterious effects. Recently, bioenergy from microalgae has gained prominence and the use of municipal wastewater as a low cost alternative for a nutrient source has significant advantages. In this study, we have employed municipal wastewater directly after primary treatment (primary settling basin) in a small scale raceway pond (SSRP) for microalgal growth. Indigenous microalgae in the wastewater were encouraged to grow in the SSRP under optimal conditions. The mean removal efficiencies of TN, TP, and $NH_3-N$ after 6 days were 77.77%, 63.55%, and 89.02%, respectively. The average lipid content of the microalgae was 19.51% of dry cell weight, and linolenate and linoleate (18:n) were the predominant fatty acids. The 18S rRNA gene analysis and microscopic observations of the indigenous microalgae community revealed the presence of Chlorella vulgaris and Scenedesmus obliquus as the dominant microalgae. These results indicate that untreated municipal wastewater, serving as an excellent nitrogen and phosphate source for microalgal growth, could be treated using microalgae in open raceway ponds. Moreover, microalgal biomass could be further profitable by the extraction of biodiesel.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.158-165
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• 2006

In this study, we investigated the biological activity of antioxidant and antibacterial activity of citrus by-product ferment. Among the six probiotic bacteria, Bacillus subtilis and Saccharomyces cerevisiae had the highest antioxidant activity. Hot water extracts from citrus by-product of ferment were screened for antibacterial activity fish pathogenic bacteria by paper disc method. Among the various hot water extracts, the Bacillus subtilis, Saccharomyces cerevisiae, Pediococcus pentosaceus, Lactobacillus rhamnosus, Lactobacillus plantarum, Enterococcus faecium showed relatively strong antibacterial activities in the order. The reducing activity on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and $O^{2-}$ and OH radical scavenging potential were sequentially screened, in search for antioxidant activities of citrus by-product ferment.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.13-22
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• 2009

The study area is a tunnelling section passing through the Yangsan Fault zone. Kyungbu express highway and national road 35 are located above the tunnel. Previous study showed that fault gouge and fault breccia were widely distributed in the tunnelling section with a maximum width of 100 m. From the present study, it is found that sedimentary rocks consisting mainly of shale are distributed at the eastern block of the Yangsan Fault and these rocks are not subject to mechanical fracturing and hydrothermal alteration. On the other hand, dacitic tuff distributed at the western block of the Yangsan Fault is largely affected by mechanical fracturing and hydrothermal alteration. The large fault zone of $50{\sim}130m$ width was formed by complex processes of mechanical fracturing and hydrothermal alterations such as chloritization, sericitization, and kaolinization. Based on the characteristics of mechanical fracturing and hydrothermal alterations, the Yangsan fault zone in the study area is geotechnically classified as four zones: unaltered zone, altered zone, altered fractured zone, and fault gouge zone. These zones show different degrees and aspects in mechanical fracturing and hydrothermal alterations, resulting in different engineering properties.