• Journal of the Korean Geotechnical Society
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• v.24 no.9
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• pp.13-21
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• 2008

Partitioning tracer method is a useful tool to characterize large domains of the aquifers contaminated with light nonaqueous phase liquids (LNAPLs). Sorption of the partitioning tracers to the organic matter content of soil can potentially influence the efficacy of partitioning tracer method. LNAPL-water partitioning coefficients of tracers ($K_{nw}$), measured by static method, showed linear relationship. Sorption isotherm tests were conducted to evaluate the sorption capacity of the soils packed in the columns and the results were appropriately represented by Freundlich sorption isotherm. The sorption of tracers proportionally increased with the increase of the organic matter content of the soil. Laboratory experiments were conducted in four columns each packed with soils of different organic matter contents to determine the potential interference effects of sorption to soil organic matter content and correction factors for the errors in estimation of LNAPLs by partitioning tracer method. Though there were no contaminants added, breakthrough curves from columns packed with mixture of Jumunjin standard sand and organic matter showed separation of tracers. Columns were then contaminated to residual saturation with kerosene and breakthrough curves were obtained. The results show that sorption of tracers to soil organic matter leads to an increase in the retardation factor (R) and hence, to an overestimation of the saturation of LNAPLs. A relation between the percentage of organic matter content and the corresponding percentage error in the estimation of NAPLs has been developed.

• Knowledge Management Research
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• v.24 no.1
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• pp.1-29
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• 2023

The COVID-19 pandemic has accelerated digital transformation across all industries and daily life. Edutech is spreading in the education field, also bringing changes in university education. Non-face-to-face online-only classes at universities have spread after the COVID-19 pandemic physical distancing started. Online-only or real-time online classes showed diverse educational imitations. 'Metaverse' started to attract attention as a learning space and community activity support platform that may solve the limitations of online education and communication. It is time to prepare an introduction strategy for the actual application of education using metaverse. This study, first, by examining previous studies and cases of metaverse application, and second, establishing a metaverse introduction framework based on the technology lifecycle model and the innovation diffusion theory. Finally, we provide an introduction strategy in steps, a specialized introduction plan according to the main users is established and presented as a scenario. We expect that this study will provide the theoretical background of the new technology introduction and the spread of metaverse research. Also, we present an efficient introduction strategy, the basis for a service model, and a practical basis for the university's value-added strategy.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.105-111
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• 2009

The study aims to propose the intelligent clustering technique that calculates the distance by improving the problems of multi-hop clustering technique for inter-vehicular secure communications. After calculating the distance between vehicles with no connection for rapid transit and clustering it, the connection between nodes is created through a set distance vale. Header is selected by the distance value between nodes that become the identical members, and the information within a group is transmitted to the member nodes. After selecting the header, when the header is separated due to its mobility, the urgent situation may occur. At this time, the information transfer is prepared to select the new cluster header and transmit it through using the intelligent cluster provided from node by the execution of programs included in packet. The study proposes the cluster technique of the intelligent distance estimation for the mobile Ad-hoc network that calculates the cluster with the Store-Compute-Forward method that adds computing ability to the existing Store-and-Forward routing scheme. The cluster technique of intelligent distance estimation for the mobile Ad-hoc network suggested in the study is the active and intelligent multi-hop cluster routing protocol to make secure communications.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.157-167
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• 2022

This study was conducted to confirm the relationship between the proactive accounts receivable management of SMEs on credit sales decision making and business performance, and to derive effective accounts receivable management plan and systematic credit sales decision making plan. Based on 455 copies of data collected through a survey targeting SMEs, it was confirmed through factor analysis, reliability analysis, confirmatory factor analysis, and model fit verification, and the research hypothesis was verified with a structural equation model. As a result of the verification, credit rating had a positive effect on financial performance, sales performance and credit sales decision, while credit control had a positive effect on financial performance, while negative effect on sales performance and credit sales decision. In the mediating effect hypothesis test, credit sales decision had a positive effect between credit rating and business performance and a negative effect between credit control and business performance. The study suggests that if small and medium-sized enterprises improve their business performance through effective accounts receivable management, they can create a synergistic effect in enhancing the business performance of companies if they simultaneously improve their proactive accounts receivable management and credit sales decision ability. Future research is required to study the impact of factors such as segmentation of research subjects and credit transaction motives and accounts receivables management.

• Korean Association of Arts Management
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• no.52
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• pp.5-37
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• 2019

Despite a copious volume of work on the relationship between social class and cultural consumption, scholars have paid scant attention to the increasingly apparent observation that a vast majority of the population exhibits indifference toward fine arts regardless of one's socio-economic status. Much of the prior literature on cultural consumption has treated the public's indifference to fine arts not as a distinct analytical category that deserves an explanation of its own, but simply as the opposite of "likes" or the act of consumption, let alone being disentangled from the concept of "dislikes" in taste-formation and consumption behavior. In this paper, we suggest that the seemingly increasing trend toward indifference to fine arts, especially among those who are part of the well-educated and economically well-off, merits close scholarly attention on its own term. As an initial step toward this endeavor, we explore the factors behind indifference toward fine arts among Korean middle-class, using the ground theory method. Our interview findings reveal that much of indifference toward fine arts is attributable to the lack of tastes in fine arts and artistic competence. Our results suggest that research drawing on Bourdieu's theory and Peterson's omnivore hypothesis needs to be further revised through an in-depth investigation of the institutional and societal contexts where art education takes place in Korea. We discuss the implications of our findings for policy-making in the cultural and artistic sphere.

• Korea Trade Review
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• v.42 no.2
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• pp.319-344
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• 2017

The international standard certification evaluates the extend to which the supplier satisfies the international standard certification standards of the supplier of the product and the service, recognizes the quality assurance ability and reliability of the supplier, thereby resolving the international trade regulation that can occur to various fields and strengthening the network of the global partnership it is making an important contribution. Therefor, in this study, the survey was conducted on 153 companies of Korean import and export companies. The research method was empirically analyzed by the structural equation model. The results of the hypothesis test of this study are as follows. First, resource management factors among the international standard certification factors in the global trade supply chain integration had a positive effects on CRM satisfaction. Second, the measurement, analysis and improvement factors of international standard certification factors had a positive effects on CRM satisfaction. Third, CRM satisfaction has a positive effects on business performance. Through this study, it is concluded that the Korean import and export companies have an important role in improving the business performance of the global trade partners.

• Journal of agriculture & life science
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• v.50 no.2
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• pp.45-52
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• 2016

In order to select excellent cross parents for development new cultivar of low temperature tolerant, combining ability was conducted by 24 cross combinations obtained from crosses between 'Dahong', 'Gamhong', 'Maehyang', 'Seolhyang' as seed parents and 'Dahong', 'Gamhong', 'Maehyang', 'Sugyeong', 'Sunhong', 'Wongyo 3111' as pollen parents. The results showed that two cultivars of 'Dahong', 'Gamhong' were not suitable for seed parents. Because average fruit weight in case of 'Dahong' as a seed parent was the tendency to become the smallest in total cross combinations, survival ratio in case of 'Gamhong' as a seed parent was the lowest in total cross combinations. And fruit hardness in case of 'Sunhong' as a pollen parent was the tendency to low, incidence of malformed fruit in case of 'Sugyeong' as a pollen parent was the tendency to be increased. Therefore, two cultivars of 'Sunhong', 'Sugyeong' was also not suitable for pollen parents. But In case of 'Maehyang' and 'Seolhyang' as seed parents, germination percent and survival rate were relatively higher than other seed parents, fruit quality and yield had also excellent. Therefore, there could be selected to 'Maehyang' and 'Seolhyang' as seed parents and 'Maehyang', 'Seolhyang', 'Wongyo3111' as pollen parents. Especially, the crosses 'Maehyang' × 'Seolhyang', 'Seolhyang' × 'Maehyang', 'Seolhyang' × 'Wongyo3111' were suitable for cross combination for development new cultivar of low temperature tolerant to be demonstrated the excellence as cross parents in sugar contents, fruit weight, fruit hardness and yield.

• Journal of The Korean Association For Science Education
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• v.43 no.3
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• pp.295-306
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• 2023

In this study, we explored science teachers' perceptions of adaptive practice in terms of importance and practice. For this purpose, an adaptive practice questionnaire was developed targeting secondary science teachers, and the responses of 128 science teachers were analyzed. The results of this study were as follows: First, the science teachers responded that all 17 items regarding adaptive practice were important. In particular, items related to 'addition of examples', 'adjustment of the level/range of concepts', and 'encouragement of student participation' showed high importance and performance levels. Second, the results of the IPA concerning adaptive practice showed that the items needing intensive improvement due to high importance but low performance were 'encouraging students' self-directed learning' and 'monitoring and responding to individual differences'. The science teachers identified a lack of time and uniform curriculum as the reasons for the low level of practice despite the high importance of these items. Third, regarding the IPA of the adaptive practice items, the items located in the fourth area, an excessive area, concerned 'pace control', 'modifying activities', and 'metaphor use'. More specifically, considering that 'metaphor use' was the only item with a higher level of performance than importance, it is necessary to reconsider whether problems are caused by excessive use. Fourth, analyzing the responses regarding the reasons for the difference in importance and performance revealed that the factors related to teachers included teachers' lack of knowledge or ability, and the tendency to implement as planned. As for student factors, an excessive number of students, differences in the levels of students, and a tendency to prefer classes centered on entrance exams were identified. As environmental factors, a uniform curriculum, conditions for experiments, evaluation systems, and external demands were mentioned. Finally, the implications of the results of this study for science education were discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6B
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• pp.503-512
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• 2009

Watershed models, which are a tool for water cycle mechanism, are classified as the distributed model and the lumped model. Currently, the distributed models have been more widely used than lumped model for many researches and applications. The lumped model estimates the parameters in the conceptual and empirical sense, on the other hand, in the case of distributed model the first-guess value is estimated from the grid-based watershed characteristics and rainfall data. Therefore, the distributed model needs more detailed parameter adjustment in its calibration and also one should precisely understand the model parameters' characteristics and sensitivity. This study uses Jungnang basin as a study area and $Vflo^{TM}$ model, which is a physics-based distributed hydrologic model, is used to analyze its parameters' sensitivity. To begin with, 100 years frequency-design rainfall is derived from Huff's method for rainfall duration of 6 hours, then the discharge is simulated using the calibrated parameters of $Vflo^{TM}$ model. As a result, hydraulic conductivity and overland's roughness have an effect on runoff depth and peak discharge, respectively, while channel's roughness have influence on travel time and peak discharge.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6D
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• pp.623-629
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• 2010

Recently, the Shield TBM (Tunnel Boring Machine) construction method is used gradually to increase at the Tunnel Constructin site. However the design and application of the Shield TBM were carried out without sufficient investigation of the ground conditions in the construction site. Due to insufficient understanding to the corresponding equipment is frequently occurring unexpected construction cost and extension of a construction period. The most suitable alternative construction method was determined by analyzing tunneling rate, duration, construction cost of shield machine and tunneling data of alternative method. The result of the case study is suggested as follows. First, the accurate soil exploration on the construction site should be preceded to prevent from tunneling stoppage and schedule delay. Second, the most suitable selection of the shield machine to the ground conditions of the construction site should be executed based on the investigation. Third, the best alternative method for boring of hard rock section is 'hard rock blasting after open cut and cover method'.