• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.59-76
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• 2020

As a continuous increase in demand for the transportation infrastructure in the metropolitan area, the renovation of existing metropolitan and urban railway lines for the rapid transport system requires the construction of sidetrack that can operate local and express trains simultaneously. However, the construction of sidetrack after stopping the operation of the existing subway line causes a lot of economic losses, therefore it is essential to study the tunnel enlargement scheme during the operation of the existing subway tunnel. Accordingly, in this paper, basic research on the enlargement plan of the existing subway tunnel was carried out for the renovation of the existing subway line. In order to investigate the method for the sidetrack construction, the Government Complex Gwacheon station on the Gwacheon line of subway line 4 was selected as a virtual research station. Subsequently, four construction plans including tunnel cross-sectional plan for each section were reviewed and constructability and economic feasibility were compared. Finally, the stability assessment was conducted for the selected construction plan which was considered to be relatively unstable by 3-D full numerical analysis considering the sidetrack construction process.

• Journal of Conservation Science
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• v.31 no.4
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• pp.411-427
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• 2015

The purpose of the present study is to examine the objects excavated from the archaeological site of the Nogye Village in terms of their relationships with the iron production facilities such as 1ho smithing hearth and 2ho smelting furnace. 32 samples including slags, iron ores, and wall were analyzed to identify the mineralogical and chemical characterization. In addition, in the case of the 1ho smithing hearth slag, differing points of the cross-section were analyzed to examine its formation in depth. The analysis results suggest that the slags from the each site adjacent to the 1ho smithing hearth and 2ho furnace are related to smithing and smelting process respectively. Furthermore, it is possible to draw some conclusions that the aspects of the increased contents of nonferrous elements such as CaO in the slags in comparison with those of the iron ores are due to various factors such as charcoal ash and analytical reasons rather than an addition of CaO as flux.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.225-232
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• 2008

An estimation has been made for inventories and characteristics of spent nuclear fuel(SNF) to be generated from existing and planned nuclear power plants based on the 3rd Basic Plan for Electric Power Demand and Supply. The characteristics under consideration in this study are dimensions, a fuel rod array, a weight, $^{235}U$ enrichment, and the discharge burnup in terms of fuel assembly. These are essentially needed for designing a pyroprocessing facility. It is appeared that the anticipated quantity by the end of 2077 is about 23,000 tU for PWR spent nuclear fuel. It is revealed that the proportion of SNF with the initial $^{235}U$ enrichment below 4.5 weight percent(wt.%) is approximately 95 % in total. For SNF with 16$\times$16 fuel rod array the proportion is expected approximately 74% in total. It appears that the average burnup of SNF will be 55 GWd/tU after the medium and/or latter part of 2010s while the average burnup is 45 GWd/tU at present. Finally, a requirement in terms of reference SNF for designing the pyroprocessing facility has been derived from the above-mentioned results. The anticipated SNF seems to be 16$\times$16 Korean Standard Fuel Assembly with a cross section of 21.4 cm$\times$21.4 cm, a length of 453 cm, a mass of 672 kg, the initial $^{235}U$ enrichment of 4.5 wt.%, and the discharge burnup of 55 GWd/tU.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.5
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• pp.179-186
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• 2007

This paper has investigated a rise of water level in upstream and downstream of bridge, which is caused by accumulation of debris in a bridge. The debris has been classified into several types in terms of size. The rise of water level which has been caused by installation and removal of sheet pile that is used to block water in a bridge has been analyzed using HEC-RAS model. According to the analysis, it has turned out that the debris has no influence on the rise of water level in ordinary water flow. In addition, sheet pile has little impact on the rise of water as well. Even though the impact of sheet file has turned out trivial in flood flow just like the ordinary water flow, it's been simulated that the maximum water level difference between upstream and downstream of bridge turned out more than 1.0meter because of debris in 80-year or more flood frequency. When the rise of water level in upstream from the cross section of the bridge was investigated based on 100-year flood frequency, besides, it has turned out that it had an influence up to 17.84km distance because of the effect of debris.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.59-63
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• 2008

Purpose: Ti thin films were deposited on slide glass and CR-39 lenses using small magnetron sputtering apparatus to of Ti thin films. Methods: The thickness of Ti thin films were measured by cross section SEM, the transmittance and reflectance of them were obtained using spectrophotometer, the refractive index and extinction of them were obtained from VASE data. Results: The transmittances of Ti thin films with 60 nm, 120 nm, 140 nm thickness were a little change within the visual region from 400 nm to 750 nm, but were increased a little amount at near 400 nm. The transmittance of 60 nm, 120 nm, 140 nm Ti thickness in d-line was 30%, 25%, 20%, respectively. Also, it was shown that the refractive indices and extinction coefficients of the Ti thin films obtained from VASE were similar to those of Ti thin film offered macleod program. Conclusions: Ti films on CR-39 with these transmittances were available for sunglass lens. It was indicated that the refractive indices and extinction coefficients of the Ti thin films were decreased with the thickness of Ti thin film, for the thickness of Ti thin films was due to very thin.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.27-30
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• 2008

Purpose: This research is that $V_2O_5$ cathode's composition is possible in low temperature. Methods: Transparent in visible spectra range and crystallographically amorphous $V_2O_5$ thin films were prepared by simple vacuum thermal evaporation on soda-lime-silica slide glass substrate. After annealing at 100$^{\circ}C$, 150$^{\circ}C$ and 200$^{\circ}C$ for 10 minutes in air, the surface morphology and the fracture-cross section of the films were investigated by field emission - scanning electron microscope. Transmittance in visible spectra range and surface roughness of the films were analyzed by ultra violet - visible spectrophotometer and scanning probe microscope, respectively. Results: As the increase of annealing temperature from 100$^{\circ}C$ to 150$^{\circ}C$ and 200$^{\circ}C$, transmittance of the $V_2O_5$ films decreased. Optical properties will be fully discussed on the basis of the surface morphological results. Conclusions: Optical transmissivity was superior in case of 100$^{\circ}C$, and could make amorphous $V_2O_5$ thin film that surface quality of thin film did homogeneity.

• Journal of Korea Technology Innovation Society
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• v.10 no.3
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• pp.509-530
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• 2007

This paper examined the relationship between innovation and firm performance by integrating industry competitive context and firm-level knowledge constructs. After controlling for firm site, age, and the presence of a union, cross-section analysis of survey data from 1,419 medium sized manufacturing firms yielded following findings. The first was the expected positive relationship between firm-level innovation and firm knowledge and also industry dynamism, as measured by the intensity of industry-level R&D. This results indicate that industries with greater aggregate levels of R&D intensity are home to higher rates of firm-level innovative activity and managers must increase their numbers of technical staff and the level of training. But the interaction between firm knowledge and industry dynamism was non-significant. Second, innovation was not significantly related to firm performance, as measured by revenue growth. This relationship was not moderated by industry dynamism and firm level knowledge. In high and low technology sectors, the relationship between innovation and performance was non-significant, consistent with the full-sample analysis. The results suggest that the effects of firm-level knowledge assets and investments in training don't work in different ways in different industry settings. This research used three control variables to analyze innovation and firm performance. Firm age was negatively associated with firm performance and did not significantly predict innovation. Firm size was positively associated with innovation and performance in the low-technology sector. The presence of a labor union was not a significant with respect to innovation.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1481-1497
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• 1998

The purpose of this study was to determine the relation between serum lipid profiles, apolipoprotein E phenotype, and dietary patterns in a cross-section of healthy individuals from Cheju-Do. Age, gender, anthropometric measurements, blood pressure, dietary consumption, drinking / smoking habits and menopausal status were surveyed. Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, fasting blood glucose, and insulin levels were measured from overnight fasting blood. The study involved a total of 286 individuals(147 men and 139 women) between the ages of 20 and 60 years old. All of the subjects were recruited from a population of healthy individuals living in Cheju-Do. The results of the study are as follows : 1) Among the males, those in their 20's had the maximum food intake, while those in their 40's had the minimum food intake. For the females, food intake was the highest for those in their 30's. Energy and nutrient intakes were directly proportional to the amount of food intake. Men in their 30's were heavier than other men and women in their 40's were heavier than other women. The activity index for men in their 20's and 30's appeared to be lower than that of men above 40. The activity index of women in their 20's appeared to be lowest among all aged groups, and the index appeared to increase from the age of 30 onwards. 2) In terms of changes In serum constituents with age, men in their 40's appeared to have the highest levels of serum constituents such as lipids, glucose, and insulin. Men in their 50's showed the highest levels of serum LDL-cholesterol and glucose. Men in their 30's showed peak levels of serum triglycerides. On the other hand, women in their 50's appeared to have peak levels of serum total cholesterol, LDL-cholesterol, and triglycerides. There was no ch:ange with age in HDL-cholesterol and insulin levels for men and women. The percentage of the subjects had the following apo E phenotypes : E3/3, 91.3% ; E3/2, 5.4% ; E4/3, 2.5% ; E4/2, 0.7%. Lee's reserch with Korean female college students showed that the percentage of ApoE3/3, E3/2, E 4/2, E4/3, and E4/4 were 84.8%, 6.7%, 6.7%, 0.9%, 0.9%, respectively. The number of samples with ApoE mutation was so small that there was no statistical significance in the relation between apolipoprotein E phenotype and se겨m lipids. 3) To investigate the relati onship between weight and serum constituents, the subjects of this study were divided into three groups by BMI underweight, normal weight, and overweight. The serum constituents of men and women below the age 40 in the overweight groups belonged to the normal domain. On the other hand, serum cholesterol levels of both men and women above the age 40 in the overweight groups remained in the borderline-high region(above 200mg/dl), and the mean value of LDL-cholesterol(above 130mg/dl) and triglycerides of men were above normal. Fasting blood glucose levels also remained in the borderline-high region. Total cholesterol levels of women above the age 40 in the overweight group was in the borderline-high region. (Korean J Nutrition 31(9) : 1481-1497, 1998)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.657-666
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• 2017

In this study, factor analysis was performed to reduce the friction in the elevation motion of a stand for a 50-inchtelevision. Pipe type cross-section control was used for accurate positioning control of the piston rod. The pipe type was also compared with a labyrinth-type crosssection for the orifice. The frictional force was then reduced using gas seal lip technology. Specifications were chosen, and a volume compensation experiment was carried out using an apparatus for compensating the volume of the cylinder, which is compressed by the volume of the piston rod. Based on CAE and experimental considerations, the labyrinth-type orifice is preferred for reducing friction. For the gas seal lip technology, outer and inner diameters of ${\Phi}20$ and ${\Phi}8$ for the hollow rod were more appropriate when assuming the weight of a 50-inch television to be 30kgf. The third is that the result of total consideration in stability problem and performance of volume compensation for specification decision and volume compensation experiment is determined the final speculation of hollow rod ?8x?4 and riveting system. The last is that the labyrinth orifice is not founded that of the ${\O}0.4{\sim}0.6$ orifice both tests on 300 mm intervals.

• Journal of Labour Economics
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• v.29 no.3
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• pp.1-23
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• 2006

This study investigates the effects of inward foreign direct investment on local workers' wages by focusing on U.S. manufacturing industries for the period from 1987 to 1992. Contrary to public perception that foreign ownership is positively associated with higher wages, previous studies show mixed results. Since most of the previous studies used industry or firm level average wages, they can not control for the impact of individual characteristics on wages. I use two different approaches to control individual characteristics and to implement estimation in this study: (1) One-step estimation with industry-state level of inward foreign direct investments by using individual level data, and (2) Two-step industry characteristic regression approach. The higher presence of foreign firms is associated with higher local wages after workers' observable characteristics are controlled for in the first approach. This effect, however, disappears once workers' industry affiliations and regions are controlled for in cross-section analysis. In a panel data analysis, I did not find any statistically significant positive association between inward FDI activities and industry wage premiums within industry. Further, inward FDI activities appeared to be negatively associated with worker's industry wage premium for workers with more than high school education.