• Journal of Broadcast Engineering
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• v.22 no.1
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• pp.28-41
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• 2017

In this paper, the fast encoding algorithm in High Efficiency Video Coding (HEVC) encoder was studied. For the encoding efficiency, the current HEVC reference software is divided the input image into Coding Tree Unit (CTU). then, it should be re-divided into CU up to maximum depth in form of quad-tree for RDO (Rate-Distortion Optimization) in encoding precess. But, it is one of the reason why complexity is high in the encoding precess. In this paper, to reduce the high complexity in the encoding process, it proposed the method by determining the maximum depth of the CU using a hierarchical clustering at the pre-processing. The hierarchical clustering results represented an average combination of motion vectors (MV) on neighboring blocks. Experimental results showed that the proposed method could achieve an average of 16% time saving with minimal BD-rate loss at 1080p video resolution. When combined the previous fast algorithm, the proposed method could achieve an average 45.13% time saving with 1.84% BD-rate loss.

• Journal of Energy Engineering
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• v.29 no.1
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• pp.63-74
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• 2020

The Kori-Unit 1 nuclear power plant, which is scheduled for decommissioning after permanent shutdown, is expected to generate a large amount of various types of radioactive waste during decommissioning process. For concrete radioactive waste, which is expected to occupy the most amount, it is important to analyze the current waste disposal status and legal limitations and to prepare an appropriate and efficient disposal method. Concrete radioactive waste is waste of various levels, of which the clearance level is bioshield concrete. In this paper, clearance radioactive waste safety evaluation was performed using the RESRAD code, which is a safety evaluation code, based on the activation evaluation results for the wastes with the clearance level. The clearance scenario of the target radioactive waste was selected and the individual's exposure dose was calculated at the time of clearance to determine whether the clearance criteria limit prescribed by the Nuclear Safety Act was satisfied. As a result of the evaluation, the results showed significantly lower results and satisfied the criteria value. Based on the results of this clearance safety assessment, the appropriate disposal method for bioshield concrete, which are the clearance wastes of subject of deregulation, was suggested.

• Journal of Engineering Education Research
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• v.10 no.1
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• pp.60-76
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• 2007

In this study, the effect of a sustainable energy design project on academic achievement for engineering freshmen at Virginia Tech in fall semester 2006 in the United States was examined by experimental method. The department of engineering education at Virginia Tech was opened in 2004. In this experiment the population was approximately 1200 freshmen, and 5 classes were sampled. Subject name is engineering exploration, a theme of the instruction is sustainable energy design, the project was performed throughout a 6 weeks period with one by 50 minutes lecture conducted by faculty and one 90 minutes workshop conducted by GTAs (Graduate Teaching Assistants) every week. The statistical results using SPSS (ver. 15.0) are as follows: A paired-samples t test analysis was run on the pre- and posttest to determine academic achievement, the results indicated a significant increase in 4 classes of mixed gender at .05 significance level, but there was no significance at 1 group of female class. A paired-samples t test analysis was run on the pre- and posttest to get an attitude score, the results showed, the posttest scores decreased for 5 groups even though it was not statistically significant. Finally, in responses to an open-ended question about students' perceptions of their improvement in skills, the 3 most frequently identified skills were teamwork, design process, knowledge.

• The Journal of Engineering Geology
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• v.5 no.2
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• pp.193-200
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• 1995

It has been well known that the alkali-aggregate reaction between the aggregates and cement paste is one of the reasons of a concrete siructre expansion. Because of a serious demage on the concrete stnicture from the expansion, in many countries, the safety of the materials is checked in laboratory by mortar-bar test and the upper limit of expansion in length is 0.1%. The prescriptions are presented in the ASTM C227 and 490 of U.S. which has been international currency and in the KS Handbook F2503, F2546 and L5107 of Korea published by Korean Standards Association. Both of the prescriptions are almost same in their contents. Actually, in the process of preparing and measuring the mortar-bar according to the prescription mentioned above, it seems that there are no problems for its own purpose but a few points are found to be improved upon the methods to increase the accuracy for laboratory work as follows. 1. The prescription of blending ratio(aggregate, cement and water) should be noted by volume not by weight. 2. It is unreasonable to measure the initial length of mortar bars after 24$\pm$2 hours at once regardless the kind of aggregates. 3. It may bring about errors in calculating the expansion ratio under the condition of the denominator value fixed as 254mm. 4. The measuring methods of specific gravity are selected according to the purposes but the pure specific gravity displays the highest accuracy among them.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.455-469
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• 2007

The study area, Bonggil-ri, Gyeongju, SE Korea, is composed of Cretaceous sedimentary rocks, and Tertiary igneous rocks and dykes. A research on fracture developing history and density distribution was carried out on well exposed Tertiary granites. The fractures developed in this area have the following sequence; NW-SE trending duo-tile shear bands (set a), NNW-SSE trending extensional fractures (set d), WNW-ESE trending extensional or normal fractures (set b), NE-SW trending right-lateral fractures (set c), WNW-ESE trending reverse fault reactivated from normal faults (set e) and NW-SE trending left-lateral faults reactivated from shear bands (set a) under brittle condition. According to the result of fracture density analysis, the fracture density in this area depends on rock property rather than rock age, and also higher fracture density is observed around fault damage zones. However, this high fracture density may also be related to the cooling process associated with dyke intrusion as well as rock types and fault movement. Regardless of the reason of the high fracture density, high fracture density itself contributes to fluid flow and migration of chemical elements.

• Journal of Engineering Education Research
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• v.12 no.1
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• pp.82-94
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• 2009

This paper examines the roles, main contents, and writing guidelines of ethical codes, and analyses the developmental process and characteristics of ethical codes of scientific and technological communities in Korea. Korean communities occasionally tried for ethical codes from the 1970s to the 1990s, and have paid a serious attention to ethical codes in the 2000s. The forms of ethical codes became more sophisticated pursuing detailed commentary and ethical education. The focus of contents changed from professional dignity to social responsibility, and the importance of research integrity became embossed in the 2000s. Scientific and technological communities in Korea should make or revise ethical codes with self-imposed control considering realistic operation.

• Journal of Engineering Education Research
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• v.22 no.6
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• pp.51-63
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• 2019

This study aims to present concept of "gong" which was shared by traditional East Asian societies (Korea, China and Japan) and to identify how it has been developed through their respective process of modernization and industrialization. Despite the territorial proximity of the three countries, their industrial and technological development followed different patterns, and the notion of engineering from the Occident was also accepted and reconstructed with a certain difference in each country. Japan had developed its own concept of engineering as part of industrialization in Western style and in the context of establishment of an imperialist nation. What was important for Japan was how engineering could contribute to the national development of technology and industry, and to the development of Imperial Japan. For China, which attached importance to resistance to Western civilizations and to strengthening the competitiveness for and which needed to resolve domestic political conflicts, engineering constituted more than a simple issue on technological and industrial dimension; it was also associated with obtaining ethical and political legitimacy which would allow the nation to gain support from the working and peasant classes. Though belated, Korean attempted to build an independent modern state, yet experienced a considerable nuisance from the invasion of Japan and the protracted colonial period. Engineering of Korea had to take a long time before emerging from backwardness especially because of Japanese policies which tended to restrict technological development and avoid fostering qualified engineers in the colony. Therefore, engineering in Korea started to contribute to the nation's development and the improvement of technological competitiveness only after it was combined with modern higher education after liberation, under the name of engineering science (工學, gong-hak). This study argues that our recognition of what engineering was for and who engineers were in East Asia will allow us to evaluate current status of engineering education and provide us with significant insight which will be useful when we imagine the future society. Identity of engineering in Korea, China, and Japan has been developed along with historical contexts such as clash of civilizations, wars, recovery of sovereignty and obtaining of national competitiveness; now, what will be combined with engineering in the next generation? This question will lead and motivate engineering students to think and imagine about what future engineering should be and how they respond to it.

• Journal of Environmental Impact Assessment
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• v.24 no.2
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• pp.154-162
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• 2015

Correlation between occupational exposure levels to toluene and urinary hippuric acid (HA) concentrations were studied for 124 workers at 54 work places. The highest indoor toluene concentration measured at printing process was 81.116 ppm, and their geometric average concentration was as high as 12.304 ppm. The geometric average concentration of hippuric acid in urine samples from workers who are exposed to toluene was 0.714 g/g creatinine. This is almost five times higher than the average HA concentration from non-exposure workers. Printing workers showed the average HA concentration of 1.145 g/g creatinine from their urine samples. It is the highest concentration among the workers exposed to toluene. The correlation coefficient between HA concentrations in urine and indoor toluene concentration at work places was relatively high as r=0.624 (P<0.01). But the correlations of HA with sex, smoking, drinking, age and employment history was relatively low. We can express the regression equation for the urinary HA concentration which is Y = 0.037X + 0.562 as exposure toluene concentration is X. The urinary HA concentrations showed significantly increase depend on indoor toluene concentration at work place.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.243-249
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• 2019

The purpose of this study is to analyze the reflectance of bed materials according to changes in the water level using a drone-based hyperspectral sensor. For this purpose, we took hyperspectral images of bed materials such as soil, gravel, cobble, reed, and vegetation to compare and analyze the spectral data of each material. To adjust the water level, we constructed an experimental channel to control the discharge and installed the bed materials within the channel. In this study, we configured 3 cases according to the water level (0.0 m, 0.3 m, 0.6 m). After the imaging process, we used the mean value of 10 points for each bed material as analytical data. According to the analysis, each material showed a similar reflectance by wavelength and the intrinsic reflectance characteristics of each material were shown in the visible and near-infrared region. Also, the deeper the water level, the lower the peak reflectance in the visible and near-infrared region, and the rate of decrease differed depending on the bed material. We expect the intrinsic properties of these bed materials to be used as basic research data to evaluate river environments in the future.

• Journal of Environmental Impact Assessment
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• v.27 no.3
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• pp.241-250
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• 2018

Recently, negative effects on human health such as disease caused by harmful environment have been dealt with seriously. In particular, studies on the effect of radon exposure, which is known as a primary carcinogen in lung cancer due to radioactive materials, have been actively studied. In Korea, since January 1, 2018, radon measurement is mandatory when building a new apartment, so it is necessary to measure the radon concentration and submit it to the local government and it should be posted where residents can see it. Radon has only recommended standards for multi-use facilities, but now it has decided to set recommendation standards for private homes. Therefore, it should now be possible to manage the radon in the environmental impact assessment phase as well as in the Post-environmental Impact Assessment. It should be possible to share health information such as the radon concentration and the risk of radon, and participation of health experts in the environmental impact assessment stage is required. Soil, air quality, hygiene and aerial items should be improved to take into account the effects of radon on human health during the environmental impact assessment process. If the level value of conncentration of radon shows above the recommended level, then alternative measures should be prepared and mitigation measures should be prepared as well.