• Membrane Journal
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• v.22 no.1
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• pp.72-76
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• 2012

$SF_6$ has an extremely high global worming potential (GWP). Therefore, there has been an effort to reduce the use of $SF_6$ and its emission into atmosphere. One possible solution for minimizing the use of $SF_6$ in electrical equipments is utilization of gas mixtures such as $SF_6/N_2$. The $SF_6$ concentration in the gas mixture varies from 10 to 60%. However, when the apparatus is repaired or dismantled, we have to recover $SF_6$ from the gas mixture. Since the boiling point of $SF_6$is low (${\sim}-60^{\circ}C$), the liquefaction method is difficult to apply. One possible alternative is the membrane separation technology. In this study, we investigated the $SF_6$ and $N_2$ permeation properties of 5 polymeric membranes. For example, permeability of $N_2$ in BOPP membrane at $25^{\circ}C$was 0.19 barrer, whereas that of $SF_6$ was only 0.0012 barrer, resulting in the selectivity of 158. An upper bound for $SF_6/N_2$ gas pair was suggested for the first time with n = -1.33 and k = 160 (barrer).

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.221-226
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• 2016

Production of eco-friendly and biologically harmless materials is strongly required in all industries. In particular, reducing volatile organic compounds in coating processes is extremely important to secure worker's safety. During recent two decades, extensive research works on water-borne polyurethane dispersion (PUD) have been continuously developed as an alternative to solvent-borne polyurethane. However, PUD was shown inferior mechanical properties to the organic solvent-borne polyurethane due to a limit to the molecular weight increase, which resulted in the limit of applications. To overcome this drawback, several approaches have been examined such as polymer blends and thermal/radiation induced crosslinking. Among these methods, the radiation curing system was suitable for industrialization because of the high crosslinking density and fast curing speed. In this study, we overcame the drawback for PUD via introducing benzophenone radiation curable units to PUD. We synthesized PUD films which possessed good dispersion in water for 30 days, increased Tg and Td more than $5^{\circ}C$ after UV curing film as well as improved young's modulus more than double.

• Economic and Environmental Geology
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• v.38 no.1
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• pp.1-22
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• 2005

Carbon dioxide ($CO_2$) is the greatest contributor among the major greenhouse gases covered by the Kyoto Protocol. Therefore, substantial efforts for the control and reduction of $CO_2$ emissions, including increased efficiency of fossil fuel energy usage, development of energy sources with lower carbon content, and increased reliability on alternative energy sources, are being performed worldwide. However, development and industrial application of $CO_2$ sequestration techniques are needed to meet the requirements of the Kyoto Protocol. Among the $CO_2$ sequestration methods developed, geological sequestration methods such as the storage in deep aquifers, deep coal seams and oil and gas reservoirs and the mineral carbonation is considered most favorable because of its stability and environmental effectiveness. In this review, geochemical concepts and technologic development of geologic sequestration technology, especially the storage in deep aquifers and the mineral carbonation, are discussed. The weakness and strengths for each of geologic sequestration methods, are also reviewed.

• Journal of Korean Philosophical Society
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• v.123
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• pp.87-110
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• 2012

The kitsch was emerged from the people's cultural desire in the conditions of the various duplicating technology, the capital economy system, and the civil revolution in the western modern mass society. But it is underestimated constantly because of the conspicious consumption and the aesthetic inadequacy. Even though some kitsches are elevated to the 'kitsch arts' in the historical description of the modern arts, still the most of kitsches are remained as 'just kitsches' and excluded from the aesthetic research according to the double standard. In this essay, I research for whether anti-kitsch theory is convincing theoretically and practically. Anti-kitsch theory criticizes the kitsch on the basis of the modernist aesthetics, in which the 'fine art' provokes the aesthetic pleasure in the disinterested contemplation. But kitsch purposes for the sensual gratification and the sentimentality. So the anti-kitish theorists conclude that the kitsch is the bad taste. In critically analyzing the argumentation of Greenberg's. Kaplan's and $C{\tilde{a}}linescu^{\prime}s$, I refute the privileged prejudice of the ideal critic. They don't justify the criteria of the classification of 'art'/ 'kitsch'. They supplement the economical and the political grounds for the evaluative theory of the kitsch. But the argumentation of the kitsch is consumed conspicuously and results in the unlettered masses is not sufficient. People produce and enjoy the kitsches in the various ways. People envelope the genres, styles and media of the kitsches and they try to suggest the new horizon of the popular aesthetics. So anti-kitsch theories cannot be accepted because they adhere to the elitism and formalism. The exclusion of the kitsch is the derogation for people's taste. Also they didn't reflect the contemporary cultural practice and the aesthetic needs in the system of post-art. The alternative aesthetics of the kitsch is the topic of my next essay.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.232-232
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• 2019

The persistence of drought periods and water scarcity is a growing public concern, as climate change projections indicate a more critical scenario in the future. The sustainability of water resources for the increasing population, and to ensuring crop production will unarguably be a daunting task for the water resources managers, with a projected 9.8 billion people by 2050 as well as the need to increase food production by 70 to 100%. Consequently, there is a need for significant irrigation water use for more crop production in the face of stiff competition among water users. However, the available natural resources are already over-constrained, and the allocation of more resources for food production is not feasible. Currently, about two-thirds of global water withdrawer is used by the agricultural sector while 48% of water resources in Korea is used for agricultural production. Despite the apparent ecological deficit and unfavorable conditions of resources utilization, a staggering amount of food waste occurs in the country. Moreover, wastage of food translates to waste of all the resources involved in the food production including water resources. Food waste can also be considered a serious potential for economic and environmental problems. Hence, exploring an alternative approach to efficient resources utilization in a more sustainable way can ensure considerable resources conservation. We hypothesized that reducing food waste will decline the demand for food production and consequently reduce the pressure on water resources. We investigated the food wastage across the food supply chain using the top-down datasets based on the FAO mass balance model. Furthermore, the water footprint of the estimated food wastage was assessed using the representative of selected food crops. The study revealed that the average annual food wastage across the food supply chain is 9.05 million tonnes, signifying 0.51 kg/capita/day and 48% of domestic food production. Similarly, an average of 6.29 Gm3 per annum of water resources was lost to food wastage, which translates to 40% of the total allotted water resources for agriculture in the country. These considerable resources could have been conserved or efficiently used for other purposes. This study demonstrated that zero food waste generation would significantly reduce the impact on freshwater resources and ensure its conservation. There is a need for further investigation on the food waste study using the bottom-up approach, specifically at the consumer food waste, since the top-down approach is based on estimations and many assumptions were made.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.408-408
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• 2019

The persistence of drought periods and water scarcity is a growing public concern, as climate change projections indicate a more critical scenario in the future. The sustainability of water resources for the increasing population, and to ensuring crop production will unarguably be a daunting task for the water resources managers, with a projected 9.8 billion people by 2050 as well as the need to increase food production by 70 to 100%. Consequently, there is a need for significant irrigation water use for more crop production in the face of stiff competition among water users. However, the available natural resources are already over-constrained, and the allocation of more resources for food production is not feasible. Currently, about two-thirds of global water withdrawer is used by the agricultural sector while 48% of water resources in Korea is used for agricultural production. Despite the apparent ecological deficit and unfavorable conditions of resources utilization, a staggering amount of food waste occurs in the country. Moreover, wastage of food translates to waste of all the resources involved in the food production including water resources. Food waste can also be considered a serious potential for economic and environmental problems. Hence, exploring an alternative approach to efficient resources utilization in a more sustainable way can ensure considerable resources conservation. We hypothesized that reducing food waste will decline the demand for food production and consequently reduce the pressure on water resources. We investigated the food wastage across the food supply chain using the top-down datasets based on the FAO mass balance model. Furthermore, the water footprint of the estimated food wastage was assessed using the representative of selected food crops. The study revealed that the average annual food wastage across the food supply chain is 9.05 million tonnes, signifying 0.51 kg/capita/day and 48% of domestic food production. Similarly, an average of $6.29Gm^3$ per annum of water resources was lost to food wastage, which translates to 40% of the total allotted water resources for agriculture in the country. These considerable resources could have been conserved or efficiently used for other purposes. This study demonstrated that zero food waste generation would significantly reduce the impact on freshwater resources and ensure its conservation. There is a need for further investigation on the food waste study using the bottom-up approach, specifically at the consumer food waste, since the top-down approach is based on estimations and many assumptions were made.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.145-156
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• 2021

This study is aimed to improve the youth theft prevention program with rationality and practicality, based on the needs of practitioners who conduct these programs in fields. The survey questionnaire was prepared based on previous researches, and the survey was conducted on 72 probation officers and education instructors nationwide running a youth theft prevention program. As a result, practitioners reported the lack of self-control and high impulsivity as the main characteristics of the theft delinquent adolescents. And they recognized peer alignment and family problems as the causes of theft. As for the contents of the program, they reported that recidivism prevention skills such as understanding psychological problems, peer relationships, raising a sense of law compliance, anger, impulse control, dealing with negative emotions, and finding alternative behaviors, as well as moral development, are necessary. These results indicate that multi-dimensional interventions such as individuals, families, and peers are needed to prevent recidivism of juvenile theft. Implications of these results, future research directions, and limitations and significance of the study were discussed.

• Land and Housing Review
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• v.12 no.3
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• pp.109-119
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• 2021

Global warming caused by greenhouse gas emissions has rapidly increased abnormal climate events and geotechnical engineering hazards in terms of their size and frequency accordingly. Biopolymer-based soil treatment (BPST) in geotechnical engineering has been implemented in recent years as an alternative to reducing carbon footprint. Furthermore, thermo-gelating biopolymers, including agar gum, gellan gum, and xanthan gum, are known to strengthen soils noticeably. However, an explicitly detailed evaluation of the correlation between the factors, that have a significant influence on the strengthening behavior of BPST, has not been explored yet. In this study, machine learning regression analysis was performed using the UCS (unconfined compressive strength) data for BPST tested in the laboratory to evaluate the factors influencing the strengthening behavior of gellan gum-treated soil mixtures. General linear regression, Ridge, and Lasso were used as linear regression methods; the key factors influencing the behavior of BPST were determined by RMSE (root mean squared error) and regression coefficient values. The results of the analysis showed that the concentration of biopolymer and the content of clay have the most significant influence on the strength of BPST.

• Korean Journal of Poultry Science
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• v.48 no.3
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• pp.111-122
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• 2021

Recently, interleukin 34 (IL-34) was identified as the second functional ligand for macrophage colony-stimulating factor receptor (M-CSFR). IL-34 functions similarly to M-CSF through its binding to the M-CSFR. There is still insufficient information on IL-34 in chickens, which has until now been reported only through predicted sequences and not through experimental research. Thus, to confirm its expression and to determine its potent biological activity, several chicken lines and cell lines were used. Cloning of recombinant chicken IL-34 and M-CSF genes was performed to investigate their modulatory effects on proinflammatory cytokine expression in vitro. The expression levels of IL-34, M-CSF, and M-CSFR genes were upregulated in broiler chickens with leg dysfunction (cause unknown). However, IL-34 was downregulated in most pathogen-stimulated tissues. M-CSFR expression was enhanced by recombinant IL-34 and M-CSF proteins in vitro. IFN-γ expression was enhanced by recombinant IL-34, but not by M-CSF. However, IL-12 expression was not regulated in any of the treated cells, and IL-1β was decreased in all tissues. These results indicate that IL-34 and M-CSF have roles in both the classical and alternative macrophage activation pathways. Collectively, our findings demonstrate the expression of IL-34 in chickens for pathogenic trials, both in vitro and in vivo. Our results suggest that the IL-34 protein plays a role in both pro- and anti-inflammatory functions in macrophages. Therefore, further research is needed to determine the cytokines or chemokines that can be induced by IL-34 and to further elucidate the functions of IL-34 in the inflammatory pathway.

• Korean Journal of Construction Engineering and Management
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• v.22 no.3
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• pp.79-90
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• 2021

In domestic public construction, disputes are increasing due to differences among stakeholders regarding contract price adjustment. In particular, the actual cost-plus fee for overhead costs due to the schedule extension cannot be agreed upon at the administrative phase, and most of them seek judicial judgment. Thus, this study aims to propose a 'sufficiently satisfactory' alternative to reach an agreement before disputes in order to minimize disputes related to the calculation of additional overhead costs. To this end, this study proposes three alternatives based on the rate method. Firstly, when calculating additional overhead costs, it is not calculated as an actual cost-plus-fee method, but as a rate compared to direct labor costs among net direct costs. Secondly, the calculated indirect labor costs are compensated for up to the legal maximum of legal limit costs such as general management costs, profits and so on. Thirdly, it reflects overhead costs increased or decreased due to change orders. Risks were analyzed by collecting expert opinions on the proposed methods and applying actual cases. Finally, as a result of investigating the level of consensus for each stakeholder, it was confirmed that all stakeholders could agree regardless of the size of the company. The result of this study is expected to as a useful tool among stakeholders in the construction fields that can be able to easily agreed upon.