• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.3
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• pp.221-227
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• 2010

The solidification methods for powder wastes dried at CWDS(Concentrate Waste Drying System) in PWR have been studied in a variety of ways both at home and abroad. The solidification for these wastes has been performed using stabilization agents such as cement, paraffin and polymer. The applicability studies to maximize the reduction ratio of wastes and operational effectiveness for wastes treatment have been carried out, recently. It is necessary to pretreat the powder wastes before feeding wastes to vitrification facility because the fines flying brings about clogging of feeding pipes and off-gas treatment system or workers' exposure to radiation during maintenance. This paper describes an effective method for treatment of powder wastes to improve safety and stability of vitrification facilities.

• Journal of the Korean Society of Child Welfare
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• no.26
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• pp.87-111
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• 2008

The purpose of this study is to evaluate the actual conditions of peer victimization and to examine how the various factors of school climate influence peer victimization. Analysis on the relationship between various school climate and peer victimization has not been yet dealt with in Korea. Participants in this study were middle school students chosen from 11 middle schools in Seoul, by convenience sampling. A total of 1,204 surveys were then analyzed. Methods for analysis included Frequencies, Descriptives, Pearson's Correlation, Hierarchical Regression. From the result of the analysis, the level of verbal violence came out to be a relatively high form of peer victimization. The hierarchical regression were conducted in two steps. The second model's descriptive variable was higher by 19.6% than the first model. The variables of interaction between teacher and student in peer violence(${\beta}=.130$), of school facility maintenance(${\beta}=.067$), of safety of school environment(${\beta}=.331$), and economic status and sex out of controlled variables were proved to be of significance, and those variables explained 23.0% of the entire model. Based on the results of this study, practical and effective policy solutions to improve the school climate better have been suggested.

• Journal of Labour Economics
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• v.43 no.4
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• pp.143-177
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• 2020

This paper investigates how the provision of full child care subsidy to infants and toddlers differently affected female labor supply and fertility rate depending on the level of supply of child care centers in the place of residence. Our results on labor supply show that the higher the supply rate of childcare centers in residential areas, the higher the probability of career maintenance for multi-child mothers who are more likely to be admitted to a childcare facility. The results on the fertility rate show that the first child's fertility rate has increased since the support of childcare expenses in areas with higher rates of childcare centers. In the places where the supply rate of publicly-funded childcare centers is high, the second child's fertility rate has also increased significantly since the support of childcare expenses. This suggests that the quality of child care is an essential factor in determining the birth rate. Our results suggest that the effects of child care support on women's labor supply and fertility rate may differ depending on the priority of entering child care centers according to birth order and the degree of quantitative and qualitative supply of child care centers in the place of residence.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.478-485
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• 2018

The study was carried out to select natural environmental factors that affect damage to hiking paths and to provide directions for facility management of hiking paths by a logistic regression analysis. The study sites is a total of 123 sample sites that located in the Baekdudaegan Guropo-Gisaengnyeong hiking trails. The variables used in the analysis model included mountain trail damage, forest type, herb of soil and crown density obtained through a field survey and included slope, soil and rock exposure obtained through FGIS. A logistic regression analysis of 43 sites and 80 undeveloped sites, 4 elements were selected for slope, herb of soil, soil and rock exposure. The slope and the herb of soil were positively correlated and the exposure of rock was negative. Soil has shown a positive correlation with its low missile and high sand ratio Saturn. Therefore, the management of the mountain hiking paths facilities should be established and restored considering the slope, herb of soil, soil and rock exposure.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.131-137
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• 2019

The purpose of this study is to investigate the perception of buildings suspended from construction and to analyze the problems that are inherent and effective in the management of public officials and residents in the area where construction is suspended. There are 63 buildings in the Gangwon area, 16% of which are occupied by the whole area. 31% of the apartment houses are occupied the most, and 10 years or more is suspended. 241 of them accounted for 62%. In order to efficiently manage buildings that are suspended from construction, protection measures should be taken to ensure safety and prevent crime through periodic and continuous management of facility grade management that conforms to the special act on safety and maintenance of facilities. Effective support for budget and personnel is required for efficient management of construction suspended.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.107-119
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• 2021

The cross-flow turbine is one of the most famous and widely used hydraulic power systems for a long time. The cross-flow turbine is especially popular in many countries and remote regions where off-grided because of its many benefits such as low cost, high efficiency at low head, simple structure, and easy maintenance. However, most modern turbines, including the cross-flow turbine, are unsuitable for the ultra-low head situation, known as less than 3m water head or zero head with over 0.5m/s flow velocity. In this study, we demonstrated a 20kW class inverted-type cross-flow turbine's performance. First, we reevaluated our previous studies and introduced how to design the inverted-type cross-flow turbine. Secondly, we fabricated the 20kW class inverted-type cross-flow turbine for the performance test. And then, we designed a testbed and installed the turbine system in the demonstration facility. In the end, we compare the demonstration with its previous CFD results. The comparing result shows that both CFD and real model fitted on guide vane angle at 10 degrees. At the demonstration, we achieved 42% turbine efficiency at runner speed 125 RPM.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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• pp.57-69
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• 2022

This study analyzes the fuel conditions and environmental effects of converting heating in rural villages that rely on fossil fuels into wood fuel. In particular, we tried to derive the most important considerations when using wooden chips as fuel in aging agricultural villages where various variables such as weather, facility characteristics, fuel quality, and maintenance capabilities work. Above all, an experiment was conducted by comparing it with oak trees to determine whether Italian poplar, a representative attribute water created to supply fuel wood in Korea, is suitable for heating fuel. Through experiments, 1) Even though the supply of poplar wood chips during 10 hours of operation was 60.74 kg less than that of hardwood chips, the production of hot water was 140 kWh higher. 2) The higher the exhaust gas temperature, the proportional (increase) oxygen concentration and inversely (decrease) PM and CO emissions. 3) Poplar has twice as much ash content as hardwood and three times more fine dust has been detected, but it meets all the standards for wood quality at the Korea Forest Science Institute. 4) Under the condition that there is a difference in water content (7.7%), hardwood cost 1.13 times more wood chips per 1 MWh than poplar, and even if the water content is corrected equally, hardwood cost 1.05 times more per 1 MWh than poplar. 5) In conclusion, it was proved that the fuel possibility, economic possibility, and environmental possibility of poplar wood chips are sufficient.

• Journal of the Korean Society of Safety
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• v.37 no.5
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• pp.42-55
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• 2022

In this study, an accident at an in-house maintenance subcontractor of a manufacturing company was analyzed using representative systemic analysis methods, and the results were compared to determine the socio-technical and organizational structure causal factors. Systemic accident analyses were performed using AcciMap, STAMP-CAST, and a method that utilizes work processing procedures. The causal factors derived from the three methods were classified according to HFACS classification criteria. AcciMap and STAMP-CAST analyses were able to derive legal problems and defects in organizational structure between the company and the subcontractors. The method that utilized the work processing procedures drew the most causal factors of the three methods but showed some limitations in deriving legal and facility-related problems. Most of the causal factors identified through the systemic methods could be classified according to the HFACS classification criteria, except for the legal and organizational structure matters. Socio-technical and organizational problems with a holistic perspective of the company and subcontractors could be found using systemic analysis methods. However, it is necessary to conduct analysis using various methods in order to derive more comprehensive measures to prevent accidents because each analysis method showed some limitations in the derivation or expression of some causal factors. The results of this study can be helpful in selecting and using an appropriate method for accident analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.45-56
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• 2022

Recently, bicycle sharing system is introduced and the usage of shared bicycles is increasing in Suwon city. Despite the need to expand the bicycle road infrastructure, this is not the case. Therefore, this research attempts to propose a method for bicycle lane installation in Suwon city. For this, this research conducted location analysis based on the shared bicycle usage data and trip inducing facility data. Using location analysis results, appropriate routes for bicycle lanes are selected. As a result, two routes are selected. These routes have advantages that it is easy to connect with the existing bicycle roads or traffic inducing facilities and to install using the existing bicycle roads. However, these routes also have disadvantage that traffic congestion may occur due to the occupancy of the existing road space. It is expected that this research may contribute to expansion and maintenance of bicycle lane infrastructure, the bicycle and PM sharing service usage, implementation of sustainable urban transportation systems in Suwon city.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.113-124
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• 2021

Underground environmental infrastructure and energy production facilities, which are recognized as avoidable facilities such as landfills, are emerging as an important social issue due to urbanization and economic growth. In order to safely construct a large-scale plant facility in the underground space, it is necessary to increase the utilization of the limited space layout and minimize unnecessary columns. In this study, the plant modularization method(Pipe Rack Module) was reviewed to solve the problems of work constraints, assembly and demolition, process system interconnection, and maintenance that occur when plant facilities are underground. In addition, plant module analysis was performed by applying various load conditions (earthquake load, device load, earth pressure load, etc.) to improve spatial layout usability and secure structure stability. Based on the analysis results under various boundary condition, the implications regarding the minimum installation interval and module arrangement (draft) of basic modules required for the construction of an underground combined plant were derived.