• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.467-474
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• 2011

In an effort to investigate water pollution characteristics of Juam lake, water samples were collected from three sites (Sites A, B, and C) of Oenam stream which is a typical tributary of rural watershed in the lake and analyzed for N concentration and the corresponding isotope ratio (${\delta}^{15}N$) of ${NO_3}^-$. Concentrations of ${NO_3}^-$ were not dramatically different among the sites; $0.8{\pm}0.2mgNL^{-1}$ (range: $0.0{\sim}4.3mgNL^{-1}$) for Site A, $1.1{\pm}0.2mgNL^{-1}$ ($0.0{\sim}4.3mgNL^{-1}$) for Site B, and $1.1{\pm}0.1mgNL^{-1}$ ($0.1{\sim}2.6mgNL^{-1}$) for Site C. Meanwhile, ${\delta}^{15}N$ tended to decrease with river flow; it was highest for Site A ($45.5{\pm}5.3$‰) followed by Site B ($19.7{\pm}2.0$‰) and Site C ($8.7{\pm}1.5$‰). Such high ${\delta}^{15}N$ values of ${NO_3}^-$ in Site A suggested that ${NO_3}^-$ derived from livestock feedlot (specifically livestock excrete of which ${\delta}^{15}N$ is higher than 10‰) is the predominant pollution sources despite mountainous area occupied the most of land-use in the watershed. Using the two-sources isotope mixing model, it was estimated that the contribution of cropping activities (i.e. fertilization) became greater in down-stream area (Sites B and C) due to the higher agricultural land-use than the up-stream area (Site A). Particularly, during the active cropping season, the low contribution of organic pollution sources indicated that domestic sewage was not the predominant pollution source. Therefore, it was suggested that agricultural sources such as livestock farming and cropping rather than mountainous and residential are the dominant sources of water pollution in the study area. These results could be effectively utilized in elucidating water pollution sources in rural areas and selecting water management practices.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.240-245
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• 2011

Vegetation changes were studied for 16 yr in clearcut logged Pinus densiflora forests in the southern Gangwon-do province in Korea by applying chronosequence approach. Ambient temperature and relative humidity, Detrended Correspondence Analysis (DCA), Multiple Responses Permutation Procedure (MRPP), Indicator Species Analysis (ISPAN) were used to examine successional trajectory and compositional changes. After clearcutting, canopy openness was increased abruptly at three folds (1yr 68.3% and R1 23.0%) and then decreased, but relative moisture was slightly decreased (6%) compare to control site. In the result of DCA, right after clear cutting, vegetation composition was developed heterogeneously compared to control sites, and then approached to control sites within 16 years. Based on MRPP, species composition of each developmental stages (1yr, 3yr, 10yr and 16yr) revealed signigicant differences to that of control vegetation (R1, R3, R10 and R16). Indicator species in 1yr and 3yr samples included various woody species rather than herbaceous species, but in 10yr and 16yr, herbaceous were more abundant. Earlier succession of pine forests likely can explain to Initial Floristic Composition (IFC) Model.

• 한국사회정책
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• v.24 no.4
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• pp.185-222
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• 2017

The purpose of this study is to investigate the effect of labor market policy on fiscal soundness of welfare state. The analysis was carried out using cross-sectional panel data regression analysis, stepwise mediating effect analysis and system GMM designed by Baron and Kenny(1986) based on the data from 1985 to 2015 for 20 OECD countries. In setting up the analysis model, this study considers the interaction effect between active and passive labor market policies as well as the time sequence of the outcomes which have been overlooked in the previous studies. The result shows that labor market policies have significant impacts on the fiscal condition of welfare states, which is measured as the levels of national debt in this study. Especially the expenditure on active labor market programs has a positive effect on improving the fiscal soundness of welfare states by promoting the employment rate. In contrast, passive labor market programs expenditure is negatively associated with employment rate growth and it exacerbates the burden of national debt in the short-term. However, when active labor market programs and passive labor market programs are combined, the negative impacts by passive pabor market policies on the fiscal soundness of welfare states are off-set. Therefore this study addresses that although the expansion of the labor market policies can be inimical to the fiscal soundness of welfare states in the short-term, in the long run, they can have effective roles in securing and promoting the fiscal soundness of the welfare states by promoting the employment rate.

• The Journal of Korean Philosophical History
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• no.41
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• pp.9-38
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• 2014

Hanhweon-dang Kim Goeng-pil(1454~1504) sublimated ethics whose lead was opened up by Jeong Mong-ju in late Goryeo as one scholarly tendency. Kim Goeng-pil was called 'the father of ethics in Joseon' and has been respected as a model of ethicist for 400 years since then. Following Kim Goeng-pil, Confucian scholars of Joseon cultivated perseverance through Xiaoxue and the perseverance was sublimated to Confucian scholars' energy and then that of state, which served as driving force to keep the national legacy. Kim Goeng-pil suggested how to study with Xiaoxue and sought moral human beings and ethically ideal societies based on strong practicability which is required in Xiaoxue. Individuals' cultivation and social reform are not at a different dimension. Spirit of 'self-cultivation' that Kim Goeng-pil himself demonstrated advanced to pursuit of ethical, ideal state when reaching a level of Jo Kwang-jo. Kim Goeng-pil thought that teaching in Xiaoxue could be achieved through 'Gyeong (敬, respect).' It is the key of Neo-Confucianism in Joseon to control one's mind through the cultivating method of 'Gyeong.' Kim Goeng-pil settled Joseon's Confucianism as 'practical ethics(心學).' Before Kim Goeng-pil, no scholars had well presented the aspects of practical ethics. After King Myeongjong and Seonjo, Confucianism in Joseon worked as the cornerstone of practical ethics. Since mid-17th century, the system of practical ethics had been firmly established with focus on 'Gyeong. Literary men of Kim Goeng-pil and scholars they fostered led the academic and political world of Joseon after mid-16th century. They played the lead in Sarim faction's(士林派) ruling after King Seonjo came to throne. The very foundation which sublimated Joseon to the ethically ideal state and made the Dynasty a 'state of Sarim' was actually laid by Kim Goeng-pil.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.104-112
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• 2021

In this study, emotional analysis was conducted based on the basic attribute data of music and the emotional model in psychology, and the result was applied to the visualization rules in the formative arts. In the existing studies using musical parameter, there were many cases with more practical purposes to classify, search, and recommend music for people. In this study, the focus was on enabling sound data to be used as a material for creating artworks and used for aesthetic expression. In order to study the music visualization as an art form, a method that can include human emotions should be designed, which is the characteristics of the arts itself. Therefore, a well-structured basic classification of musical attributes and a classification system on emotions were provided. Also, through the shape, color, and animation of the visual elements, the visualization of the musical elements was performed by reflecting the subdivided input parameters based on emotions. This study can be used as basic data for artists who explore a field of music visualization, and the analysis method and work results for matching emotion-based music components and visualizations will be the basis for automated visualization by artificial intelligence in the future.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.285-294
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• 2021

This study analyzes the factors that determine the attitude toward the electronic wristband(smartband) to check the position of self-quarantine subjects due to COVID-19. Furthermore, I analyze the interaction of class and age among the factors that determine attitudes toward the electronic wristband. In this study, the attitude toward self-quarantine electronic wristband is analyzed as a binary logit model, focusing on class and age. As a result of the analysis, the middle class significantly agreed with the self-quarantine electronic wristband compared to the lower class, and the older the person, the more in favor. On the other hand, the interaction between the class and the age shows that the age weakens the positive effect on the attitude of the self-quarantine electronic wristband in the middle and upper middle classes. The implication of this study is that it is necessary to push for mandatory electronic wristband in areas with high proportion of high-aged people with positive attitude toward self-quarantine electronic wristband and in the same age group, the approval rate is low, so it is necessary to promote mandatory electronic wristband in areas where the vulnerable class is dense.

• Resources Recycling
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• v.30 no.3
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• pp.3-17
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• 2021

Currently, there is a drain of natural resources, environmental contamination, generation of waste, and problems of the earth's climate by CO₂ emissions according to mass production and overconsumption of mankind. It is effectuated by a linear economy that involves manufacturing products, use, and waste repeatedly; there is no guarantee in the lives of humans and the future of the globe if we do not find alternative proposals. For a sustainable developing society and to overcome the present global problems, we must successively change to a circular economy from a linear economy. The circular economy has the concept of an extended value chain in recovery, reuse, remanufacturing, and recycling, instead of discarding after the use of manufactured goods. New business models of circular economy have been realized to save the earth ecology and sustainable developing society in serious recognition of the linear economy system. New business models are established by creating a vision and developing a program, and by renovating technology, law, and financial support through a worldwide government policy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.183-191
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• 2021

Non-intrusive load monitoring is a technology that can be used for predicting and classifying the type of appliances through real-time monitoring of user power consumption, and it has recently got interested as a means of energy-saving. In this paper, we propose a system for classifying appliances from user consumption data by combining GAF(Gramian angular field) technique that can be used for converting one-dimensional data to the two-dimensional matrix with convolutional neural networks. We use REDD(residential energy disaggregation dataset) that is the public appliances power data and confirm the classification accuracy of the GASF(Gramian angular summation field) and GADF(Gramian angular difference field). Simulation results show that both models showed 94% accuracy on appliances with binary-state(on/off) and that GASF showed 93.5% accuracy that is 3% higher than GADF on appliances with multi-state. In later studies, we plan to increase the dataset and optimize the model to improve accuracy and speed.

• Journal of IKEEE
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• v.25 no.2
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• pp.399-407
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• 2021

This paper proposes the DC-link voltage design method of Type 4 wind turbine that minimizes power loss and satisfies the High Voltage Ride Through(HVRT) function requirements of the transmission system operator. The Type 4 wind turbine used for large-capacity offshore wind turbine consists of the Back-to-Back converter in which the converter linked to the power grid and the inverter linked to the wind turbine share the DC-link. When the grid high voltage fault occurs in the Type 4 wind turbine, if the DC-link voltage is insufficient compared to the fault voltage level, the current controller of the grid-side converter can't operate smoothly due to over modulation. Therefore, to satisfy the HVRT function, the DC-link voltage should be designed based on the voltage level of high voltage fault. However, steady-state switching losses increase further as the DC-link voltage increases. Therefore, the considerations should be included for the loss to be increased when the DC-link voltage is designed significantly. In this paper, the design method for the DC-link voltage considered the fault voltage level and the loss is explained, and the validity of the proposed design method is verified through the HVRT function simulation based on the PSCAD model of the 2MVA Type 4 wind turbine.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.555-561
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• 2020

In this study, the applicability of Hunt's analytical solution for a two-layered leaky aquifer system, which was developed to estimate stream depletion due to the groundwater pumping of the upper shallow aquifer, was evaluated. The 5-year averaged stream depletions were estimated using Hunt's analytical solution for various combinations of hydraulic characteristic values such as transmissivity, storage coefficient of the two aquifers, interlayer leakage coefficient, stream-well distance, hydraulic conductivity of the streambed, and stream width. Through comparison with the numerical solution accurately simulated with a MODFLOW groundwater flow model, the analytical solution derived by regarding the stream width as a point was evaluated. It was found that the error in the stream depletion calculated by the analytical solution can be reduced to less than 0.05 when the stream-well distance is greater than the stream width or when the stream depletion factor (SDF) is more than about 3,000 days. In addition, when the streambed hydraulic conductivity is less than 1 m/d, the hydraulic diffusion coefficient of the lower aquifer layer is less than 100 ㎡/d, the hydraulic diffusion coefficient ratio of the upper and lower aquifer layers is 5 or more, and the leakage coefficient between the layers is less than 0.0004 m/d, the overall analytical solutions were overestimated compared with the numerical solutions.