• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.8
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• pp.418-428
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• 2005

In this paper, a new probabilistic generation modeling method which can address the characteristics of changed electricity industry is proposed. The major contribution of this paper can be captured in the development of a probabilistic generation modeling considering generator maintenance outage and in the classification of market demand into multiple demand clusters for the applications to electricity markets. Conventional forced outage rates of generators are conceptually combined with maintenance outage of generators and, consequently, effective outage rates of generators are newly defined in order to properly address the probabilistic characteristic of generation in electricity markets. Then, original market demands are classified into several distinct demand clusters, which are defined by the effective outage rates of generators and by the inherent characteristic of the original demand. We have found that generators have different effective outage rates values at each classified demand cluster, depending on the market situation. From this, therefore, it can be seen that electricity markets can also be classified into several groups which show similar patterns and that the fundamental characteristics of power systems can be more efficiently analyzed in electricity markets perspectives, for this classification can be widely applicable to other technical problems in power systems such as generation scheduling, power flow analysis, price forecasts, and so on.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.804-806
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• 2005

In this paper, a new probabilistic generation modeling method which can address the characteristics of changed electricity industry is proposed. The major contribution of this paper can be captured in the development of a probabilistic generation modeling considering generator maintenance outage and in the classification of market demand into multiple demand clusters for the applications to electricity markets. Conventional forced outage rates of generators are conceptually combined with maintenance outage of generators and, consequently, effective outage rates of generators are new iy defined in order to properly address the probabilistic characteristic of generation in electricity markets. Then, original market demands are classified into several distinct demand clusters, which are defined by the effective outage rates of generators and by the inherent characteristic of the original demand. We have found that generators have different effective outage rates values at each classified demand cluster, depending on the market situation. From this, therefore, it can be seen that electricity markets can also be classified into several groups which show similar patterns and that the fundamental characteristics of power systems can be more efficiently analyzed in electricity markets perspectives, for this classification can be widely applicable to other technical problems in power systems such as generation scheduling, power flow analysis, price forecasts, and so on.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.78-89
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• 1994

The radionuclide release rates from the engineered barrier composed of concrete structure and clay-based backfill in a low and intermediate level waste repository were assessed. Four types of release pathway were considered, and the contribution of each pathway to the total release were analyzed. To quantify the effect of uncertainties of input parameter values on the assessment of radionuclide release rates, the Latin Hypercube sampling method was used, and the resulting release rate distribution were determined through a goodness-of-fit test. Finally, the ranges of maxi-mum release rates ore estimated statistically with a confidence level of 95%.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4039-4047
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• 2023

This contribution describes the application of HPGe detector for the airborne quantitative analysis. The hardware of the airborne HPGe system was designed from the commercial components with only exception of the newly designed AirHPGeSpec special software to control, measure and process the data. The system was calibrated for the local air kerma rates measured on helicopter board and its conversion to the air kerma rates at 1 m above the ground was proposed. Two examples of the air kerma rates measured over the former uranium mining areas are presented and compared with the results of other airborne system on the board. This airborne HPGe system could be also used for measuring the surface activities in a radiation event. The nuclides of ¹³¹I, ¹³²Te - ¹³²I, ¹³³I, ¹³⁴I, ¹³⁵I, ¹³⁷Cs, ¹³⁴Cs, ⁸⁸Rb and ¹⁰³Ru were selected from possible nuclear power plant emergency scenarios. The Monte Carlo simulation was used to calculate HPGe detector efficiencies for the flight altitudes from 25 to 300 m for the energies from 300 keV to 3 MeV of the nuclides in question. Also, the detection limits according to the Currie method as well as ISO 11929-2010 for selected nuclides are presented.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.266-271
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• 2001

Soybean can produce high-N residue due to N-fixation, so soybean rotation may increase yield of subsequent corn and reduce N fertilizer on the corn fairly. To find out the contribution of nitrogen to subsequent corn following soybean cultivation, soil nitrate, corn yield, and nitrogen uptake were measured for three continuous corn cropping years after soybean rotation. Three N rates of 0, 80, and 160 kg/ha were applied to three continuous corn following soybean cropping. At 6-leaf stage, soil nitrate amount at the soil depth of 0-30cm ranged from 60 to 80 kgN/ha higher in the first corn cropping year than that in the second and third corn cropping years. Judging from corn N status such as SPAD value, N concentration of ear-leaf and stover at silking stage, N contribution of previous soybean to corn in the first corn year was N fertilizer of approximately 80 kg N/ha. Stover N uptake at silking stage increased from 47 to 52 kg N/ha at the 0, and 80 kg N/ha of N rates in the first corn cropping year compared with those in the second and third corn cropping years. Corn grain yield at the 0 kg N/ha of N rate was 6-7 ton/ha higher in the first corn cropping year than that in the second and third corn cropping years, respectively. When compared the first corn year following soybean cropping with the second and third corn cropping years, N uptake of grain and stover at harvest with low N rates such as 0 and 80 kg N/ha increased from 45 to 67kg N/ha, from 35 to 60 kg N/ha, respectively. N uptake of whole plant by soybean rotation increased from 93 to 118 kg N/ha in the first year compared with that in the second and third corn cropping years. However, the N contribution by soybean cropping was small in the second and third continuous corn cropping years. Therefore, it was concluded that the nitrogen fertilizer of 80-100 kg N/ha in the first corn cropping year could be saved by soybean rotation and annual alternative corn-soybean rotation could be the best rotation system.

• Journal of Korean Society of Forest Science
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• v.73 no.1
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• pp.43-54
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• 1986

This study was carried out to investigate the influence of light intensity on the growth of Korean white pine (Pinus koraiensis) seedlings. The seedlings were grown under four different relative light intensities: 100%, 63%, 37%, and 19% of full sunlight by covering with saran screen on seed bed. The results obtained were summarized as follows; 1. The highest shoot elongation was found at 37% in relative light intensity (RLI) plot, and the best growth in root, seedling length and diameter increment appeared at 100% on RLI plot. Contribution rates of shading to growth in shoot elongation, root growth, seedling length, and diameter increment were 9.3%, 26.2%, 21.0%, and 48.7%, respectively. 2. The greatest number of one-year-old needle fascicle was found at 100% in RLI plot, whereas that of two-year-old needle fascicle appeared at 37% in RLI plot. The contribution rate of the light intensity to number of needle fascicle was 3.9% and factor of leaf age contributed to number of needle fascicle in 27.8%. The length of needles grown under different light intensities varied with needle ages. The longest length of new needles appeared at 37% in RLI plot, but old needles were not clear in influence of light intensity. The contribution rate to needle length by the light intensity was 2.5%. 3. The heaviest value of the fresh and dry weight of seedlings appeared at 100% of RLI plot then decreased with light intensity. The contribution rates to fresh and dry weight by the shading were 38% and 7.6% respectively. 4. The largest value of the dry weight of needles appeared at 100% of RLI plot and then decreased with light intensity. The contribution rates to dry weight of needles by the light intensity was 13.18%. 5. The values of T/R ratio increased with decreased light intensity and the contribution rate was 7.0%. 6. Positive correlation and linear regressions were recognized between dry weight of leaf and other factors (dry weight of shoot, root, seedling and diameter increment).

• Journal of Digital Convergence
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• v.13 no.12
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• pp.31-39
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• 2015

This paper examines trends of the income inequality index and the income quintile share ratios, using the Household Survey released by Statistics Korea. We discuss their respective effects on total income inequality and the income disparity, as a contribution concept defined in this paper for 1990-2014 periods. Main findings are as follows. First, the contribution of 2-person families to total inequality with the current income or the disposable income becomes bigger, and growth rates have been above 10% since 2003. Second, the contribution of 1-person families to income inequality is greater than that of 2-person families. Policy implication is such that the government had better investigate the 1 or 2 person families in-depth to set up the policy measures for weakening the income inequality.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.517-533
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• 2018

We utilize the CAMx (Comprehensive Air Quality Model with eXtensions) system and the PSAT (Particulate Source Apportionment Technology) diagnostic tool to determine the $PM_{2.5}$ concentration and to perform its source apportionment in the southeastern region of South Korea. For a year-long simulation, eight local authorities in the region such as Pohang, Daegu, Gyeongju, Ulsan, Busan-Gimhae, Gosung-Changwon, Hadong, and all remaining areas in Gyeongsangnam-do, are selected as source areas based on the emission rates of $NO_x$, $SO_x$, VOC, and primary PM in CAPSS (Clean Air Policy Support System) 2013 emissions inventory. The CAMx-PSAT simulation shows that Pohang has the highest $PM_{2.5}$ self-contribution rate (25%), followed by Hadong (15%) and Busan-Gimhae (14%). With the exception of Pohang, which has intense fugitive dust emissions, other authorities are strongly affected by emissions from their neighboring areas. This may be measured as much as 1 to 2 times higher than that of the self-contribution rate. Based on these estimations, we conclude that the efficiency of emission reduction measures to mitigate $PM_{2.5}$ concentrations in the southeastern region of South Korea can be maximized when the efforts of local or regional emission controls are combined with those from neighboring regions. A comprehensive control policy planning based on the collaboration between neighboring jurisdictional boundaries is required.

• Health Policy and Management
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• v.31 no.3
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• pp.364-373
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• 2021

Background: This study aims to examine the regressiveness of national health insurance (NHI) premium burdens for local subscribers. The government has established a restructuring of health insurance contributions in 2017. Therefore, insurance premium reform began in 2018 and the second national health insurance premium reform will be carried out in 2022. We will analyze local subscribers before and after the policy reform of 2018. Methods: This study used data from 'local premium imposition elements' in the health insurance statistics annual reports (2017-2019) on National Health Insurance Service (NHIS). This study was calculated contribution rates according to levels of income and property for local insured by the method of comparing. Simulations of primary and secondary reforms were conducted in the study to determine regressiveness. Results: Insurance premiums for local subscribers were analyzed separately by income and property insurance premiums. In the income premium analysis, the higher the income, the lower the premium rate, and then the fixed rate was maintained from a certain section. The regressiveness of income insurance premiums has been eased in part. On the other hand, the property insurance premium burden was found to be regressive still by income class. Conclusion: Regressiveness analysis showed that a decrease in income contributions was achieved to local insured in the first phase of reform. But in the second phase of reform, more consideration should be given to reductions of property premium portions of local subscribers. Based on the results, the author suggested policy discussions to reorganizing the new systems of NHI contribution of local Insured.

• Journal of the Korean Ceramic Society
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• v.14 no.2
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• pp.73-77
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• 1977

The surface diffusion coefficients for nickel, nickel oxide, cuppric oxide, cobalt oxide, alumina and ferric oxide have been determined at various temperatures using the sintering technique. This investigation is based on the model accounting for the sum of the contribution of volume and surface diffusion to the overall shrinkage rate during the initial stage of sintering. Simultaneous measurements of shrinkages and shrinkage rates of the materials compacts were conducted for various annealing times, the results of which were then correlated to the diffusion coefficient.