• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.731-751
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• 2021

The Internet of Things is a huge group of devices communicating each other and the interconnection of objects in the network is a basic requirement. Choosing a reliable device is critical because malicious devices can compromise networks and services. However, it is difficult to create a trust management model due to the mobility and resource constraints of IoT devices. For the centralized approach, there are issues of single point of failure and resource expansion and for the distributed approach, it allows to expand network without additional equipment by interconnecting each other, but it has limitations in data exchange and storage with limited resources and is difficult to ensure consistency. Recently, trust management models using fog nodes and blockchain have been proposed. However, blockchain has problems of low throughput and delay. Therefore, in this paper, a trust management model for selecting reliable devices in a fog-based IoT environment is proposed by applying IOTA, a blockchain technology for the Internet of Things. In this model, Directed Acyclic Graph-based ledger structure manages trust data without falsification and improves the low throughput and scalability problems of blockchain.

• Journal of Korean Theatre Studies Association
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• no.48
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• pp.385-419
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• 2012

Son Jinchaek got into his directing career since 1976 when he founded the theatre group Minye with Huhgyu and others. His experience in Minye was the turnaround of his life; Huhgyu was a teacher in his artist's life whereas Brecht was a teacher for his ideology to make 'Korean Theatre'. From these two teachers, he learned how and why Korean Theatre should be made. Since then, Korean theatre was his calling for 40 years of his directing career. As he established Michoo in 1986, it served a turning point in his art. His focus was on intrinsic attributes of Korean Theatre with Madang Jungshin. With Madang Jungshin, he tried to get over the former generation's fixation on external materials of Korean traditional theatre and folk culture to make Korean Theatre. Rather, he believed Korean Theatre could be realized when it grafted Korean social reality onto the stage, while the form was subsequent. He advocated Korean Theatre should mirror present social reality and circulate social energy. Also, he did not give up aesthetics. On the contrary, his aesthetic style was conspicuously evident in his productions. In spite of his life long career with noteworthy works, the critical discourses are strikingly scarce especially when compared with other senior and peer directors such as Hugh Gyu, Ahn Minsoo, Oh Taesok, and Lee Yoontaek. During his career he has crossed into various genres from Changeuk, Madangnori, and to theatres, which were too versatile to thread them into a discourse and caused a lack of theoretical greeting. Madangnori has anchored its artistic structure on its polished aesthetics which were acclaimed by the general audience for 30 years. For theatre, he concentrated on one production per year to grasp its own style. Theatre works also had revealed his own style of being opened and of being emptied which was certainly different from Madangnori, but had same aesthetic principle within it. This paper attempts to recompose his stylistic features with 'Madang aesthetics' which were based on open space, open acting style, and graphic ensemble. This paper tries to demonstrate how his 'Madang aesthetics' has refined his productions in scenography, acting style, and in more like metaphoric and metonymic symbolic expression of the graphic ensemble. To do this, two productions were explored: eLee Chunpoongjeun and Yulha Ilgyee Manbo. Madangnori was sorely explored by Son Jinchaek with his artistic colleagues Yoon Munshik, Kim Jongyeup, Kim Sungnyu, music designer Park Buhmhoon, and choreographer Guk Sooho. Though it has been ignored for its popular appeal by the doctrinaire theoretical opinions, it started to pull academic attention recently. His theatres are also getting sharp with his 'Madang aesthetics' as well as minimalistic expression in scenography, acting style, and graphic ensemble. Madang Jungshin is the soul and Madang aesthetics is the body in his artistic works. The Madang Jungshin animates the Madang aesthetics, so they become alive in his theatre.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.529-538
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• 2018

The port industry is an important national industry which significantly affects Korea's imports and exports which are centered on economic structure. For instance, the Port of Busan, which handles 75% of domestic container freight volume, is expected to become increasingly critical for container liner routes. For this reason, there have been continued efforts to expand freight service to attract international freight volume. This study analyzes the structural characteristics of the port network connected to the Port of Busan by analyzing the pattern of the container liner route from 2012 to 2016 by using social network analysis. According to the Port of Busan's liner route network, the port with the highest degree of centrality, closeness centrality, and betweenness centrality was found to be the Port of Singapore. The comparison of Busan's annual container handling rank by countries and the port center network analysis of Port of Busan rank was found to be different. As a result, it was established that China's East Port, which occupies a high percentage of the volume of cargo handled by Port of Busan, is not a hub port of Busan when viewed on the Busan's container terminal liner network. In addition, even if the number of Port of Busan container liner service increases, it is estimated that the vessels to be added to the fleet will be limited to small to medium sized, or that Busan port has characteristic of a feeder port for the Port of Singapore, according to the network.

• Applied Chemistry for Engineering
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• v.30 no.4
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• pp.435-444
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• 2019

In this study, two types of nonionic saccharide biosurfactants, GP-6 and GP-7, were prepared from coconut oil and the structure of resulting products was investigated by FT-IR, $^1H-NMR$ and $^{13}C-NMR$ spectrophotometer. The interfacial properties of GP-6 and GP-7 were found to be excellent from interfacial property measurements such as critical micelle concentration, static and dynamic surface tensions, interfacial tension, emulsification power, wetting property and foam stability. Detergency test evaluated by using a Terg-o-tometer showed moderately good detergency compared to that of conventional surfactants used in detergent formulations. Biodegradability, acute oral toxicity, acute dermal irritation and acute eye irritation tests revealed that both surfactants possess excellent mildness and superior environmental compatibility indicating the potential applicability to detergent products formulations. In particular, GP-6 can be considered as a strong candidate in detergent formulations since it is more surface active, mild and readily biodegradable than GP-7.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.222-235
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• 2019

Since Fukushima nuclear disaster occurred in 2011, the nuclear energy policy of the international society has been in recession. However, In Korea, the nuclear-friendly policy had remained and even expanded over the last 60 years until the Park Geun-hye government. In other words, there was the path dependence of nuclear energy policy. Since the Moon Jae-in government that pledged to perform nuclear phase-out policy in 2017 was inaugurated, the nuclear-friendly policy began to swerve from the course of path dependence. Based on the mai logic of historical institutionalism, this study looked into the change of Korean nuclear policy by before and after the Fukushima nuclear accident. As the result of this research, the external situation of Fukushima Nuclear Accident became a critical turning point and led to a change in the government's policy on nuclear power. From an institutional perspective, it influenced the paradigm of nuclear power policy, policy decision structure, and laws of nuclear power. From a doer's perspective, it influenced political idea and social acceptability. Since Moon Jae-in government was inaugurated in 2017, nuclear phase-out policy has secured its institutional foundation and nuclear power policy has basically changed from nuclear-friendly policy to nuclear phase-out policy. Therefore, the energy policy of Moon Jae-in government gets out of the nuclear power based path dependency that previous governments pursued, keeps punctuated equilibrium, and changes to renewable energy oriented policy.

• Biomolecules & Therapeutics
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• v.27 no.5
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• pp.474-483
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• 2019

Vascular endothelial growth factor (VEGF) plays a pivotal role in pathologic ocular neovascularization and vascular leakage via activation of VEGF receptor 2 (VEGFR2). This study was undertaken to evaluate the therapeutic mechanisms and effects of the tetrapeptide Arg-Leu-Tyr-Glu (RLYE), a VEGFR2 inhibitor, in the development of vascular permeability and choroidal neovascularization (CNV). In cultured human retinal microvascular endothelial cells (HRMECs), treatment with RLYE blocked VEGF-A-induced phosphorylation of VEGFR2, Akt, ERK, and endothelial nitric oxide synthase (eNOS), leading to suppression of VEGF-A-mediated hyper-production of NO. Treatment with RLYE also inhibited VEGF-A-stimulated angiogenic processes (migration, proliferation, and tube formation) and the hyperpermeability of HRMECs, in addition to attenuating VEGF-A-induced angiogenesis and vascular permeability in mice. The anti-vascular permeability activity of RLYE was correlated with enhanced stability and positioning of the junction proteins VE-cadherin, ${\beta}$-catenin, claudin-5, and ZO-1, critical components of the cortical actin ring structure and retinal endothelial barrier, at the boundary between HRMECs stimulated with VEGF-A. Furthermore, intravitreally injected RLYE bound to retinal microvascular endothelium and inhibited laser-induced CNV in mice. These findings suggest that RLYE has potential as a therapeutic drug for the treatment of CNV by preventing VEGFR2-mediated vascular leakage and angiogenesis.

• The Korean Journal of Archival Studies
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• no.50
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• pp.311-349
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• 2016

This study reviewed how the appraisal process of the research records of the cases of Australia and the United States can be planed and managed. As the records schedule includes the list of core records and the appropriate disposal instructions, as well as the fact that it is a critical records management tool, the records schedule was considered for the basis of the research records appraisal system. The results of this study are as follows. First, the research records have to be appraised by research project because research is carried out into project units, and records management is effective when combined with the business practice and basic structure of the operating system. Second, the research institutions have to plan and manage one general disposal schedule and plural disposal schedules in the different research divisions. Finally, the characteristics of research style and the research record of each research institution should be recognized. Moreover, there is a need to link the research appraisal process of each research institution and the national records management system because the research records of public research institutions are public goods. Although various cases were not analyzed, this study is significant that the meaning and role of the research records schedule was reorganized. Also, a discriminatory records schedule according to the characteristics of research records was suggested.

• The Korean Journal of Archival Studies
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• no.52
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• pp.119-170
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• 2017

This study aims to analyze the environment for the open-source records system and to identify the risk and requirements for the success of the strategy in Korea. For this, Chapter 2 presented a review of the strategic benefits of open source to public organizations, developers, and users. It also discussed the process of cooperatively developing and releasing the source code and the technology infrastructure supporting open source. In Chapter 3, six representative open-source projects in the field of records management were selected, and case studies were conducted. To derive comprehensive implications, we have divided the main development body of open-source projects into international organizations, international cooperation systems, national archives, and software development companies. We also analyzed the background and purpose of each project, the agents of development and funding, the governance model, the development period and cost, the business model and software architecture, the community composition, and the licensing strategy. Through this, we have derived four critical success factors. In terms of technology, a component-based design was required; therefore, we proposed a microservice architecture and a model-view-controller design pattern. Next, it was necessary to reestablish system requirements of records center and archives. Moreover, we also proposed a dual licensing strategy to allow developers to easily participate in open-source projects. Lastly, we emphasized a strong governance structure and an effective cooperation framework to create a sustainable community. For a record system to be open-source successfully in an organization-centered market, the roles of software developers and end users should be exercised more in the community. To achieve this, it is important to build various collaborative tools and development infrastructure from a planning stage to a centralized one.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.303-307
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• 2019

Sophorolipid is a biological surfactant of the glycolipid structure produced by Candida bombicola, which generally exists as a mixture of acidic and lactonic forms. In this study, we investigated physico-chemical properties, antibacterial activities, and cytotoxicity of the sophorolipid containing more than 96% of the lactonic form, produced by the gene regulation of production strains and application of a metabolic engineering technique. The lactonic sophorolipid showed a weak acidity in the range of pH 3.2~4.6 when diluted in water at the concentrations from 1 to 0.001 wt%. The $pK_a$ value of the lactonic sophorolipid was estimated to be around 4.3 from the acid-base titration curve. The critical micelle concentration (CMC) of the lactonic sophorolipid was $10^{-2}wt%$, at which the surface tension of aqueous solution was reduced to 36 mN/m. The lactonic sophorolipid showed the minimum inhibitory concentrations (MIC) of $1{\times}10^{-3}$ and $5{\times}10^{-3}g/mL$ against Propionibacterium acnes and Corynebacterium xerosis, respectively. The MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay showed that cytotoxicity of the lactonic sophorolipid was ten times lower than that of triclosan.

• Journal of Korea Water Resources Association
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• v.54 no.2
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• pp.105-119
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• 2021

An increase in the frequency and intensity of both floods and droughts has been recently observed due to an increase in climate variability. Especially, land-use change associated with industrial structure and urbanization has led to an imbalance between water supply and demand, acting as a constraint in water resource management. Accurate rainfall-runoff analysis plays a critical role in evaluating water availability in the water budget analysis. This study aimed to explore various continuous rainfall-runoff models over the Soyanggang dam watershed. Moreover, the ensemble modeling framework combining multiple models was introduced to present scenarios on streamflow considering uncertainties. In the ensemble modeling framework, rainfall-runoff models with fewer parameters are generally preferred for effective regionalization. In this study, more than 40 continuous rainfall-runoff models were applied to the Soyanggang dam watershed, and nine rainfall-runoff models were primarily selected using different goodness-of-fit measures. This study confirmed that the ensemble model showed better performance than the individual model over different flow regimes.