• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.40-41
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• 2018

The purpose of this study is to compare the amount of critical chloride of rebar embedded in concrete according to the substitution rate of admixture. In order to determine the starting point of corrosion of rebar, electrodes were embedded in concrete, chloride was supplied, and OCP of rebar was observed in real time. The amount of the contaminants in the concrete surrounding the rebar was judged to be the critical corrosion chloride contents of the rebar at the start of the corrosion. As a result of the comparative evaluation, it was confirmed that the critical chloride contents of the rebar decreased with increasing the substitution ratio of the admixture.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.124-129
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• 2003

Recently, on the internet, we need the protection methods of digital contents. To Protect web contents, we inserted a visible watermark but it could be removed easily and covered some place of original contents. In this paper, we proposed a logo detection algorithm that it insert an invisible logo watermark and extract after attacks. Previous works, it didn't show clearly. Experimental results show that it can be extracted all logo images after an attack. And it is proved that proposed scheme is an appropriate algorithm.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.32-33
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• 2013

This study was a result of laboratory test to confirm the porperties of concrete containing the domestic artificial lightweight aggregate. The domestic artificial lightweight aggregate is made with bottom ash which waste material in the thermal power plant. In the experimental result air contents of fresh concrete was measured lower than other artificial lightweight aggregate. This air contents is important for retaining the resistance of freezing and thawing. Therefore air contents of concrete will be considered for retaining the resistance of freezing and thawing when manufacture the concrete containing the domestic artificial aggregate.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1379-1394
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• 1993

The purpose of this study is to examine the purification efficiency of the septic tank method which has been applied by the most of Korean livestock farms, in terms of anaerobic and aerobic treatment. Except several days in summer, BOD of effluent shows 1,500 -3,000 ppm by anaerobic process. In most cases , it exceeds according to the seasons show an increase by decrease of temperature. The removal effect on T-N is hardly found. The suspended solids contents of effluent are reduced to the level of 50-90%. Although BOD contents of effluent are kept high in the beginning, the removal rate of BOD shows 80 percent in the latter half by the aerobic treatment . The removal efficiency of total nitrogen does not appear through the experimental period, but the contents of T-N are not increased in the aerobic process unlike in the anaerobic process. The total phosphorous contents in effluent keep a constant level of 14 mg/L in average. The removal rate of phosphorous shows 91 percent i the last stage.

• Journal of Korean Elementary Science Education
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• v.24 no.5
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• pp.546-557
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• 2005

The purpose of this study was to analyze the characteristics of the geology-related contents in the 1st~7th elementary science curriculum. Our analysis was based on the analytical frameworks of geology-related contents (the structure of the contents, the amount of teaming, the contents of the experimental activities, the transitions of the terminology, and the change in the number of illustrations). The results are as follows: 1. Consistently covered contents were limited to weathering of the rock and soil, igneous rock, sedimentary rock, metamorphic rock, and the change of the earth's, fold and fault, earthquake and volcano, geologic stratum and fossil. 2. The geological contents account for (average), 11.5% (maximum), and 5.1% (minimum) of the elementary science curriculum. Most contents covered in the curriculum were rock and soil, and the change of the earth's surface. 3. Continuously covered experimental contents were the weathering and soil, igneous rock, change of the earth's surface, geologic stratum and fossil. 4. The terminology on the rock was the most frequently changed. Whenever the curriculum changed, the addition, deletion, or renaming of terminology led to confusions. 5. In terms of the transition of illustrations, the pictures replaced the figures or diagrams as the representative illustration methods as the science or the textbook compilation skill develope. The cartoons or tables were also used increasingly in order to help the children to understand and pay attention to study.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.10a
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• pp.23-28
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• 1993

Shearing properties of soil reinforced with discrete randomly oriented inclusions depend on soil density, particle size, grading, fiber length, tensile strength and stiffness of fiber, mixing ration of fiber, confining stress, etc.. In this paper the effects of those various factors on shear strength of the fiber-reinforced soil was evaluated through triaxial tests and uniaxial tests. Tests were performed on two sandy soils and one silty soil with inclusions in varing lengths, contents and tensile strengths and tested at different confining stresses in triaxial test. From the experimental results, it was investigated if there is an optimal range of fiber lengths and fiber contents for the tested soils.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.340-343
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• 2003

To effectively adopt individual customer's preference and actively adapt change of business situation, suppose an architecture of the system which include information categorization using user's preference. In the experimental results, it is found that information providing system implemented by this idea is more flexible than existing systems in extension of usage of information and goes beyond the traditional models.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.372-375
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• 2003

To effectively adopt individual customer's preference and actively adapt change of business situation, suppose an architecture of the system which include information categorization using user's preference. In the experimental results, it is found that information providing system implemented by this idea is more flexible than existing systems in extension of usage of information and goes beyond the traditional models.

• International Journal of Contents
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• v.5 no.2
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• pp.32-37
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• 2009

A new video watermarking scheme with robustness against collusion and synchronization attacks is presented. We propose to embed only a few copies of the watermark along the temporal axis into frames, which are located at the borders of each two different plotlines of the video. As a result, each change of the video plotline is transformed into pulse, which is used for watermark embedding and extraction. In addition, since we embed a watermark only into a small number of frames, the distortions of the video are reduced to minimum. Experimental results show the robustness of the proposed scheme.

• The Journal of the Korean dental association
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• v.13 no.6
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• pp.529-531
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• 1975

This observation was carried out to investigate the phosphatase activity and the calcium contents of periapical granuloma in patients of both sex and different age. The results were as follows : 1. Acid phosphatase activity was considerably increased with bone absorption. 2. Alkaline phosphatase activity was also remarkably increased in periapical granuloma. 3. In case of periapical granuloma, differences of phosphatase activity by age and sex were not observed. 4. Calcium contents in periapical granuloma was of very small quantity, showing remarkable decrease when compared with the normal bone tissue.