• Fire Science and Engineering
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• v.18 no.2
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• pp.49-56
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• 2004

Today's popular ventilation systems include the combined jet fans and electrostatic precipitation systems or the combined jet fans and vertical shaft system. Tunnels with these two ventilation systems applied have been designed and opened, more and more interest has been put in maintenance of a tunnel after opening. Therefore. it is to become more important to come up with the optimal operation mode and the method for the evaluation of ventilation system. In this study, to evaluate a tunnel ventilation and its economy, a dynamic simulation program was developed which can simulate the unsteady-state tunnel air velocity and concentration of pollutants according to the traffic flow variations and operation condition of a ventilation system. We clarified the effectiveness usage on tunnel ventilation by using it and also we could found the most economical ventilation operation mode by application in real exit tunnel. We obtained that combination of fan system and electrostatic precipitation system was more economical than jet fan priority operation mode.

• Fire Science and Engineering
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• v.24 no.1
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• pp.31-39
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• 2010

Although the subject of sprinkler installations in Korean regulations is less strict than in other advanced countries, many building owners and managers tend to install sprinklers only in the types of buildings designated by law or create building designs for which sprinkler installation standards are not applied. This is because priority is given to cutting installation expenses rather than providing building fire safety. In this study, the benefit is estimated for various expenses from installation and maintenance of sprinklers as an investment. As a result of comparing sprinkler system installation expense and the financial benefit by efficiency analysis, the payback period is 1/20 of the building life expectancy and its efficiency is twice the expense. Therefore, installation of sprinklers by regulation has financial efficiency and it is desirable to broadly encourage the installation of sprinklers.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.33-40
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• 2011

The purpose of this research is to seek political implications for management and activation of National Forest Complex Management(NFCM). Survey method was utilized for workers as respondents to measure importance and performance of NFCM. As a result, it turned out that the respondents' performance was very high. In addition, out of 14 items, two items -1) activation of e-commerce and direct business transaction, 2) production and sales marketing information, which intensive management strategy, were derived from results. Also, 6 items were derived for on-going maintenance, 3 items were derived for low priority order, and other 4 items were derived for discouragement against excessive efforts. This research may contribute to providing fundamental sources that can be utilized for promoting direction establishment and system improvement of NFCM.

• Korean Journal of Construction Engineering and Management
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• v.20 no.6
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• pp.74-80
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• 2019

In domestic construction industry, CM companies perform overall project management tasks such as planning, designing, construction management, evaluation, maintenance for construction projects. However, even with these tasks, as competition becomes more fierce and probability dependence is high, lots of CM companies are experiencing difficulties of securing and preparing indicators for order competence reinforcement. This study examines domestic business condition and task analysis. Also Competence factors are derived through institutional and legal investigation, and review of existing literature. The derived competence factors are focused on practical factors by interviewing with experts. competence factors for each type were classified into BSC's four perspectives(Finance / Customers / Internal processes / Learning and Growth) and surveyed. Based on the results of the survey, the priorities of competence factors that companies should focus on were derived. The purpose of this study is to contribute on making an indicator that can be utilized on business activities through priority analysis of competence factors for order competitiveness reinforcement of CM companies.

• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.450-459
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• 2010

The present paper investigates the collapse pressure of cylinders with intermediate thickness subjected to external pressure based on detailed elastic-plastic finite element (FE) analyses. The effect of the initial ovality of the tube on the collapse pressure was explicitly considered in the FE analyses. Based on the present FE results, the analytical yield locus, considering the interaction between the plastic collapse and local instability due to initial ovality, was also proposed. The collapse pressure values based on the proposed yield locus agree well with the present FE results; thus, the validity of the proposed yield locus for the thickness range of interest was verified. Moreover, the partial safety factor concept based on the structural reliability theory was also applied to the proposed collapse pressure estimation model, and, thus, the priority of importance of respective parameter constituting for the collapse of cylinders under external pressure was estimated in this study. From the application of the partial safety factor concept, the yield strength was concluded to be the most sensitive, and the initial ovality of tube was not so effective in the proposed collapse pressure estimation model. The present deterministic and probabilistic results are expected to be utilized in the design and maintenance of cylinders subjected to external pressure with initial ovality, such as the once-through type steam generator.

• 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 Water and Wastewater
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• v.34 no.6
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• pp.495-502
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• 2020

The 37 indicators for performance evaluation of public sewage management agencies are divided into four major categories (agency manpower management ability, wastewater treatment plant operation and management, sludge and water reuse, service quality) in the first stage, and the necessity and score acquisition for the detailed indicators by each major category in the second stages. Priority was investigated through the Analytic Hierarchy Process (AHP) analysis technique for ease and relevance of company efforts. Also, based on the results of this analysis, integrated type weighting and relative importance were analyzed. As a result of the analysis, the weight and relative importance of the first stage classification were in the order of wastewater treatment plant operation and maintenance, operation agency manpower management ability, sludge and water reuse, and service quality. As a result of analyzing the weights and priorities of the detailed performance indicators in the second stage, it was found that operator's career years, the percentage of certification holding rate in operators, compliance with the effluent water quality standards, training times for operators, and efforts to manage hazardous chemicals were important. Some of the indicators of operation agency performance evaluation may include indicators in which the performance of the company's efforts is underestimated or overestimated. In order to improve this, it is necessary to give weights in consideration of the necessity of the indicator, the relevance of the company's efforts, and the ease of obtaining scores.

• Journal of Urban Science
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• v.10 no.1
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• pp.29-37
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• 2021

The number of old buildings older than 30 years in Korea continues to increase from 29.9% in 2005 to 38.8% in 2020. Considering the growing urban regeneration projects, urban maintenance projects, the suppression of urban expansion, and the lack of idle land in the city, the dismantling of old buildings is expected to increase further in the future. As major accidents at building dismantling sites continue to occur, related agencies are also strengthening safety management of building dismantling works. While physical safety management such as collapse and fall is strengthened, there is a relative lack of interest in the health of workers at dismantling sites due to environmental hazards. Since relevant laws stipulate that construction waste should be separated and discharged, old buildings need to be considered for environmental hazards such as fine dust, floating bacteria, and floating molds when dismantling. In this study, we intend to find important safety management elements in the management of building dismantling sites, measure environmental factors harmful to dismantling workers, and present basic data for the management of dismantling sites in the future. "Safety management" was the highest priority, followed by "dust," "vibration," "noise," "bacteria," and "smell." The perception of the importance of "physical damage prevention" with workers working on dismantling and managers managing the site came out similar, but the perception of "work efficiency" and "health disorder prevention" through environmental hazard management showed different priorities. In the process of dismantling, floating bacteria and floating mold were collected, cultured, and measured the concentration in the indoor air. The measurement was measured by dividing it into pre-dismantling and during dismantling.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.233-238
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• 2022

The purpose of this study is to improve the curriculum to revitalize beauty tourism by analyzing the difference in importance and satisfaction of the beauty tourism curriculum. And online and offline surveys were conducted for workers in the beauty tourism industry, and IPA analysis was conducted using 208 valid samples. As a result of the analysis, it was found that there was a difference in the importance and satisfaction of all educational contents. And than, it was found that there were no educational contents that needed improvement, and the training courses that required continuous maintenance were field practice, major practice, service and manners, customer consultation, customer management, marketing, and interpersonal relationships. Education content with low priority was found to be foreign languages, multicultural understanding, tourism, and beauty management. Based on the results, directions for improving the curriculum for revitalizing beauty tourism were suggested.

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1167-1175
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• 2022

In this study, management index method has been developed to estimate the level of deterioration, applied to Cheongju city, and compared with the previous estimation methods of deterioration level of water distribution system. From the results, distribution systems of Yullyang, Naedeok1 and Yongam2 are found to be seriously deteriorated. And it was also found that probability of pipe breakage was estimated as 3.21%, 4.64% which is highest level at the steel pipe of 200 mm and 300 mm diameter. It was found that risk degree was estimated as 0.2609, 0.2644 by using management index method in Naedeok1 which is the most dangerous distribution system in the city. It was also found that results of risk analysis by management index method have been similar with the results of safety analysis by reliability method and indirect estimation method of deterioration level. Therefore, newly developed management index method can be applied and may be useful to the estimation of deterioration level for the future maintenance and management of water distribution system.