• Korean Journal of Construction Engineering and Management
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• v.18 no.4
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• pp.27-35
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• 2017

Based on Income-approach, this study develops the evaluation model which reflects construction industry's traits. Using Income approach, we derive future income's present value and evaluates the technological value by contribution to future income. As there exist more random variables in construction technology than in standardized manufactured products, we cannot help relying on not only quantitative estimation method but also qualitative evaluation by technology and market experts when we estimates construction technology value. Also, conservative estimation is needed for discount rate and cash-flow estimation, because of high uncertainty in sales and profits in construction industry. In empirical analysis, we applied economic periods of duration and cash-flow based on the standard guideline, and analyzed discount rate and technology factor based on characteristics of construction industry. The discount rate is estimated to 15% because of risk-premium increase by conservative evaluation. Technology factor is estimated to 46.7%, because technological intensity is estimated to 72% by technological superiority. Such implications can be inferred. Firstly, we need to build a database to diversify categories for division of sectors by activity or industrial classification which is now categorized only by two sectors in standard guideline. Secondly, the roles of experts who participate in technology evaluation are important because of volatility of construction technology.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.758-766
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• 2008

To evaluate homologue patterns and removal efficiency before and after water treatment, the concentrations of dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) were determined in 122 samples from 42 drinking water treatment plants throughout Japan over a two year period. The mean concentrations and toxic equivalent (TEQ) values of dioxins in raw and treated waters were 60.24 pg/L (0.14 pg-WHO-TEQ/L) and 4.15 pg/L (0.016 pg-WHO-TEQ/L), respectively. The dioxins contribution ratio of drinking water in relation to dioxins tolerable daily intake (TDI, 4 pg-TEQ/kg/day) was 0.016%. The mean TEQ removal rate of dioxins by drinking water treatment was over 88%. However, the mean removal rate of 2, 3, 7, 8-TeCDF (tetrachlorodibenzofuran) by water treatment in the 122 samples was minus 17%. Therefore, to identify which process affected the level of 2, 3, 7, 8-TeCDF, the removal efficiencies at both the advanced and conventional water treatment plants were investigated. For the TEQ removal rate across the processes, the dioxin congeners, TeCDF and non-ortho-PCBs remarkably indicated minus values after chlorination in both the advanced and conventional water treatments plant. From this study, the level of 2, 3, 7, 8-TeCDF was found to be increased as a result of chlorination.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.619-625
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• 2012

This study was conducted to investigate the variation of fruit, seed and germination characteristics among populations of Serrateleaf Pearlbush (Exochorda serratifolia S. Moore) distributed in Korea. Fruits collected from 96 trees in five natural populations and their five fruit, seven seed and three germination characteristics were analyzed. In 14 characteristics except for mean germination time, there were significant differences among populations and among individuals within population. Generally, fruit and seed characteristics showed higher values among population in total variance component. Coefficients of variations in weight of fruit (27.0%), length/thickness of seed (28.1%) and germination rate (52.5%) were relatively high compared to other traits. In seed germination behaviors, germination percentage, mean germination time and germination rate showed 62.9%, 64.0 days and 0.40 ea./day, respectively. As a result of simple correlation analysis, mean germination time showed a significant positive correlation with seed thickness, germination rate showed a significant positive correlation with height of parent tree and latitude, respectively. Also, latitude showed a positive correlation with fruit weight. The populations close geographically did not show the tendency of clustering into the same group. The results of principal component analysis showed that the first for principal components (PC's) explained 63.0% of the total variation. Primary 3 principal components appeared to be major variables because of the loading contribution of 97.0%.

• Journal of Labour Economics
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• v.30 no.3
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• pp.43-75
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• 2007

This study reviews the trend of job separation rates for three years from 2002 to 2005 and investigates the various elements which influence this trend, especially the role of the labor unions, by using Korean Labor Panel data. In the basic statistics, the job retention rate of union members were higher by an average of 28.3% points compared to non-union members, but in the results of controlling the observed variables of individual influences in changing jobs, it was estimated that unions increase the job retention rate by 11% to 13% points. To investigate the effect of unions on the job stability of workers in detail, the non-linear decomposition method developed by Fairlie (2003) was used in the analysis. In examining the difference of job separation rates between union members and non-union members through observed variables of workers in explainable parts and unexplainable parts by using the non-linear decomposition technique, the contribution of the explainable part was estimated to be 67% to 74% and the unexplainable part accounted for the rest which was 26% to 33%. This suggests that not only does the union contribute to the job stability of its members, but the propensity to change jobs for a worker who is a union member is on average lower than that of a worker who is not a union member or who works at an establishment that does not have a union. The results of the empirical analysis show that the job stability effect of labor unions is limited within the boundary of a maximum 7% to 9% points. The reason for the effect of labor unions on job stability being so low is due to various reasons such as collective bargaining structure by company, intensified business competition after the financial crisis, and labor market segmentation.

• International Commerce and Information Review
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• v.16 no.2
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• pp.157-183
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• 2014

The aim of this study is to establish a detailed strategic countermeasure for Korean west coast ports(Pyeongtaek Dangjin Port, Incheon Port, and Gwangyang Port) to be developed into core ports in the Pan-Yellow Sea area as the results such as strategic partnership ports analysis through the container volume analysis in Korean ports are comprehensively taken into account between west coast ports and other major ports in the Pan-Yellow Sea area. This study utilized related data which import and export data by Office of Customs Administration and SPIDC by Ministry of Maritime Affairs and Fisheries for analyzing container volume between two ports. Strategic partnership ports were selected based on in-depth analysis on 5 standards such as container volume in 2012, increase rate of trading, occupancy rate, variance rate, and contribution of container volume. As a result of selection strategic partnership port in Pan-Yellow Sea area, Lianyungang, Tianjin, Yantai, Qingdao, Dalian port in Pyeongtaek Dangjin Port, Shidao, Weihai, Qingdao, Tianjin, Dalian port in Incheon, Qingdao, Yantai, Dalian, Lianyungang port in Gwangyang port. Also this study proposed implications of countermeasure to establish strategic partnership ports for each of west coast ports.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.148-153
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• 2011

EMRAS-2 (Environmental Modelling for RAdiation Safety, Phase 2) is an international comparison program, which is organized by the International Atomic Energy Agency (IAEA), in order to harmonize the modelling of radionuclide behavior in the environment. To do so, the urban contamination working group within EMRAS-2 has designed the hypothetical scenarios for a specified urban area. In this study, the importance of contaminated surfaces composing an urban environment was analyzed in terms of dose rate using METRO-K, which has been developed to take a Korean urban environment into account. The contribution of contaminated surfaces to exposure dose rate showed distinctly a great difference as a function of specified locations and time following a hypothetical event. Moreover, it showed a distinct difference according to the existence of precipitation, and its intensity. Therefore, if an urban area is contaminated radioactively by any unexpected incidents such as an accident of nuclear power plants or an explosion of radioactive dispersion devices (RDDs), appropriate measures should be taken with consideration of the type of surface composing the contaminated environment in order to minimize not only radiation-induced health detriment but also economic and social impacts.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.1
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• pp.11-21
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• 2014

Objective : This study set out to combine the treatment efficacy of Taraxacum with Dongchimi fermentation and investigate Taraxacum's effects on protection of liver cell and controlling nitric oxide(NO) through experiments, thus checking whether it had values as a physiological active matter. The experimental materials include Taraxacum Dongchimi (TD) and Taraxacum fermented by Dongchimi (TDF). As for methodology, experiments were carried out to compare TD and TDF in components, protection effects for liver cells, anticancer effects on liver cells, and protection effects for brain cells in the aspects of liver function and immunity enhancement. Method : The experimental materials include Taraxacum Dongchimi (TD) and Taraxacum fermented by Dongchimi (TDF). As for methodology, experiments were carried out to compare TD and TDF in components, protection effects for liver cells, anti-cancer effects on liver cells, and protection effects for brain cells in the aspects of liver function and immunity enhancement. Results : As shown in the chromatogram results, each valid component content increased in Taraxacum fermented by Dongchimi (TDF) for each time section. Of them, the valid component content at 36.80 minutes was approximately 2.7 times higher in TDF at 21.8% than in Taraxacum Dongchimi (TD) at 8.28%. TDF generated more excellent protection effects against the toxicity that caused oxidative damage to the liver cell(HepG2) with t-BHP than TD. The survival rate was low in TD of $100{\mu}g/m{\ell}$ and $300{\mu}g/m{\ell}$ and increased to 23.3% in TDF of $100{\mu}g/m{\ell}$. The survival rate was the highest at $300{\mu}M$ with a significant difference of 68.1%(P<0.05). Both TD and TDF showed effects of controlling nitric oxide production according to concentration with TDF recording a higher rate of controlling nitric oxide production than TD. There were significant differences(P<0.05) in the effects of controlling nitric oxide production at 200 ug/ml, 400 ug/ml in both groups. Especially the result TDF of $400{\mu}g/m{\ell}$ was thus similar to those of butein, the positive control group. Conclusion : The result of this studies is that Taraxacum fermented by Dongchimi (TDF) increased the valid component content compared with the simple mixture(TD). The findings clearly show that it is a material with the effects of improving immunity and liver cell protection. If fermentation methods are further developed to use it as a functional material, it will be subject to more opportunities of being used in other functional foods and make a contribution to integrated medicinal food development.

• Journal of the Korean Applied Science and Technology
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• v.40 no.3
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• pp.425-434
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• 2023

An analysis was conducted on landfill gas generation and surface emission by major routes for three landfill sites of S Landfill in the metropolitan area. LS1, which had a total landfill gas generation ratio of 10.9%, accounted for 49.4% of the total surface emissions. The total surface emission of methane alone was 13.6 Nm³/min in the three landfill sites. Among them, the surface emission of methane at LS1, LS2, and LS3 was 8.4(61.7%), 4.0(29.4%), and 1.2 Nm³/min(8.9%), respectively. By emission path in the upper, slope, and dike, it was 7.3(53.2%), 6.4(46.7%), and 0.02 Nm³/min(0.1%). The dike section of the major surface emission areas showed the largest oxidation rate at 87.5%, followed by the upper at 72.3%, and the slope at 71.8%. Based on methane generation, LS1 had the largest surface emission contribution rate, with 61.7% of the total by S Landfill. By major emission path, the slope section of LS1 accounted for 41.7% of the total, the upper section of LS2 24.4%, and the upper section of LS1 20.0%, which accounted for 86.1% of the total methane surface emission of S Landfill. Therefore, it is concluded that intensive management will be necessary.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.21-32
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• 2023

Interrill erosion dominates in forest areas, and the erosion rate in surface-disturbed areas is significantly increased by the development and expansion of rill. In this study, soil erosion experiments using simulated rainfall and inflow were performed to understand the development and the micromorphological changes of rill on steep slopes. The characteristic factors of the micromorphology, such as the rill cross section, rill volume, rill density, rill order, and rill sharpness, were analyzed according to steepness and location (upper or lower) of slope. The head-cut of the simultaneous incised rills by rainfall simulation moved rapidly upslope, and the randomly developed rills expanded deeply and widely with their connection. The rill cross section evolved to downslope gradually increased. The rill volume occupied about 78 % of the sediment volume, confirming that the contribution of the sediment from the rill erosion is greater than that of the interrill erosion. Although the rate of increase in rill order slowed as the slope increased, the total length and density of the rill generally increased. As the slope increased from 15° to 20°, the bed incision of rills became larger than the sidewall expansion, and the rill sharpness increased by 1.6 times. The runoff coefficient on the lower slope decreased by 12.3 % than that on the upper slope. It was evaluated that the subsoil exposures and formation changes by the rill expansion increased the infiltration rate. Although the sediment accompanying the rills generally increased with slope increase, it was directly influenced by the hydraulic velocity of enhanced rill with the local convergence and expansion in the process of the rill evolution.

• Economic and Environmental Geology
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• v.18 no.1
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• pp.65-92
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• 1985

A total of 12 mineral commodities significant in domestic output, economy and/or strategy of the Republic of Korea are chosen to examine the structural changes in production and demand-supply of these minerals during the last two decades of her industrialization. These include iron and manganese ores as the raw materials for iron and steel making, copper, zinc and tungsten ores among other non-ferrous metallic minerals, limestone (cement), kaolin, talc, pyrophyllite and graphite among other non-metallic minerals, and anthracite coal as the only domestic source of fossil energy. These are reviewed historically in time-series based on the statistical data which are tabulated and graphed in terms of domestic output, export, import, apparent demand-supply, its increasing rate, and self-sufficiency rate of each commodity. The increasing rates of demand-supply (IRDS) of some more important commodities are compared with those of Gross Domestic Production (GDP) and Economic Growth Rate (EGR) to evaluate how the IRDS contributed to the GDP and EGR. The major results revealed are as follows: Among the 12 commodities, the domestic output of 8 commodities appeared to have grown with steady upward trends: they are ores of lead, zinc and tungsten, limestone (cement), kaolin, talc, pyrophyllite and anthracite coal. Two commodities, ores of iron and copper, continued with unchanging or slightly declining trends and varied fluctuations, in spite of their cardinal importance to the heavy industry and strategy of Korea. The remaining two, graphite and manganese ore, have gradualy declined in domestic output in which the former has still enough resource potential but the latter has not and virtually ceased its domestic output. Trade patterns for mineral commodities in the Republic of Korea during the last two decades have changed greatly, being marked by a shift from mineral-exporting to mineral importing, mainly because of increasing consumption of mineral raw materials for industrialization rather than beceuse of decreasing output of domestic mineral commodities in quantity. In terms of trade patterns, the 12 commodities concerned in this study can be classified into the following four groups. The 1st group - ores of lead and tungsten have only been exported without imports. The 2nd group - amorphous graphite, and pyrophyllite have mainly been exported but partly been imported. The 3rd group - kaolin, talc and crystalline graphite have equally been exported and imported, but quantity of imports have rapidly been increased with time. The 4th group - ores of iron, manganese and zinc have shifted from exports to imports during the industrialization, particularly owing to the initiation of iron and steel making by the Pohang Iron and Steel Company in the middle 1970' s and the new establishment of the Onsan Zinc Refinery in the late 1970' s. All of the 12 commodities under considerations were far above 100% in self-sufficiency rate before or in the early 1960' s. Recently, however, most of them have been declined to below 100% except for those of limestone (cement) and pyrophyllite. It is particularly serious to identify that the self-sufficiency rates of the three important metallic minerals, iron, copper and manganese ores in 1982 appeared to be 5.1%, 0.5%, and 0.01%, respectively. The average self-sufficiency rate of the total domestic minerals produced in 1982 was 14.4% (in value) for that year. Mining industry appeared to be extremely high in its intermediate demand rate whereas its intermediate input rate to be quite low indicating that mineral raw materials have been exerted strong forward linkage effects upon the other industries rather than backward linkage effects. In comparing the curves of increasing rates of demand-supply of several major minerals - iron ore, manganese ore, copper ore, limestone (cement), kaolin, and anthracite coal - with those of Gross Domestic Production and Economic Growth Rate drawn on every graph, it is clearly shown that the curves of increasing rates of demand-supply comprise around 6 to 7 periods of cycles which roughly harmonious with those of the curves of GDP and EGR, except for the curve of anthracite coal of which the configuration seems to have resulted from the (artificial) government's mineral policy rather than from economic free market mechanism. The harmonic feature of these curves well suggests that the increasing rates of demand-supply of major minerals have been significantly contributed to the GDP and EGR. In addition, the wider amplitudes of the iron, manganese and copper curves than those of the limestone (cement) and kaolin curves indicate that the contribution of the former, metallic commodities, has been greater than that of the latter, non-metallic commodities.