• Design & Manufacturing
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• v.15 no.2
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• pp.11-16
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• 2021

Recently, three-dimensional (3D) cell culture systems, which are superior to conventional two-dimensional (2D) vascular systems that mimic the in vivo environment, are being actively studied to reproduce drug responses and cell differentiation in organisms. Conventional two-dimensional cell culture methods (scaffold-based and non-scaffold-based) have a limited cell growth rate because the culture cannot supply the culture medium as consistently as microvessels. To solve this problem, we would like to propose a 3D culture system with an environment similar to living cells by continuously supplying the culture medium to the bottom of the 3D cell support. The 3D culture system is a structure in which microvascular structures are combined under a scaffold (agar, collagen, etc.) where cells can settle and grow. First, we have manufactured molds for the formation of four types of microvessel-mimicking chips: width / height ①100 ㎛ / 100 ㎛, ②100 ㎛ / 50 ㎛, ③ 150 ㎛ / 100 ㎛, and ④ 200 ㎛ / 100 ㎛. By injection molding, four types of microfluidic chips were made with GPPS (general purpose polystyrene), and a 100㎛-thick PDMS (polydimethylsiloxane) film was attached to the top of each microfluidic chip. As a result of observing the flow of the culture medium in the microchannel, it was confirmed that when the aspect ratio (height/width) of the microchannel is 1.5 or more, the fluid flows from the inlet to the outlet without a backflow phenomenon. In addition, the culture efficiency experiments of colorectal cancer cells (SW490) were performed in a 3D culture system in which PDMS films with different pore diameters (1/25/45 ㎛) were combined on a microfluidic chip. As a result, it was found that the cell growth rate increased up to 1.3 times and the cell death rate decreased by 71% as a result of the 3D culture system having a hole membrane with a diameter of 10 ㎛ or more compared to the conventional commercial. Based on the results of this study, it is possible to expand and build various 3D cell culture systems that can maximize cell culture efficiency by cell type by adjusting the shape of the microchannel, the size of the film hole, and the flow rate of the inlet.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.529-537
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• 2021

Membrane-type hull and cargo holds have been designed and built for large ship. However, there is a growing interest in applying the same technology to small and medium-sized Liquefied natural gas(LNG) carriers to meet the recent increase in demand for LNG as an ecofriendly fuel and for expanding LNG bunkering infrastructure. The purpose of this study is to apply the IMO Type-B tank to small and medium-sized LNG carriers and verify the safety and suitability of the design. Fatigue crack propagation analysis was performed to install a partial second drip tray installed at the lower part of the LNG cargo tank by calculating the amount of leaked gas in the support structure supporting the cargo tank. First, a program for fatigue crack propagation analysis was developed, in which Paris' law and British Standard 7910 (BS 79110) were applied based on the International Code for the Construction of Equipment and Ships Carrying Liquefied Gases in Bulk, an international standard for LNG carriers. In addition, a surface crack propagation analysis was performed. Next, a methodology for assuming the initial through-crack size was developed to determine the size of the partial second barrier. The analysis was performed for 15 days, which is a possible return time after cracks are detected. Finally, the safety and suitability of the IMO Type-B for LNG cargo tanks required by international regulations were verified. For the accurate analysis of fatigue crack propagation, it is necessary to develop and verify the analysis procedure based on direct analysis and international regulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.212-220
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• 2021

National R&D investment has steadily increased, reaching number 5 in the world as of 2018. However, for public technology commercialization, the level of discovery of policy models through various cooperation initiatives between government ministries is insufficient, and the performance system that can spread technology commercialization is also limited. In this respect, in order to create results in public technology commercialization, it is necessary to prepare alternatives to strengthen multi-ministerial policy cooperation and increase policy execution power. In this paper, we analyzed the current state of national R&D projects by major ministries and suggested an optimized technology commercialization plan through analysis of the structure, budget, and form of each project. In particular, an alternative in terms of policy efficiency was suggested by analyzing the problems of policy discovery that have not been studied previously. This study is of great significance in that it diagnosed problems of public technology commercialization in terms of the lack of systematic research on public technology commercialization and suggested policy advancement for the spread of technology use and the strategic direction in terms of commercialization.

• Environmental and Resource Economics Review
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• v.30 no.1
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• pp.129-167
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• 2021

The emission trading system is an essential policy for reducing greenhouse gas emissions and converting low-carbon society. EU ETS is a good benchmark that is ahead of Korea's emission trading system in terms of operating period and design know-how. Therefore, this study focused on the key design elements of EU ETS phase 4 such as total emission allowances issued (Cap), free allocation method, carbon leakage list, market stability reserve, and innovation supporting system. In addition, we analyzed the impact of key design elements and their changes during EU ETS Phase 1 to 4 on the design and operation of Korea emission trading system in the future. First of all, the expected impact on the design of Korea emission trading system is to increase three demands: preparing benchmark renewal plans, establishing criteria for selecting free allocation industries that reflect domestic industrial structure and characteristics and introducing two-stage evaluations for free allocation industries, and preparing specific plan to support innovation and industries using allowance auction revenues. The next three impacts on the operation of Korea emission trading system are the increased needs for objective and in-depth impact assessment of plan and amendments, provision of system stability and response opportunities by quickly confirming plan and amendments prior to the implementation, and coordination of the emission trading system governance and stakeholder participation encouragement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.888-895
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• 2020

In the construction industry, off-site construction (OSC) is drawing attention as a production method due to changes in working hours and the supply and demand of manpower. In 1991, there was a policy of spreading and expanding the use of precast concrete (PC) apartment homes, but they have not been actively used so far since they were discontinued due to quality problems. In this study, policy tasks were analyzed to motivate the application of OSC-based PCs in the apartment housing sector, and policy directions were derived by conducting focus group interviews (FGI). Nine policies are suggested regarding the following topics: PC apartment supply quantity provision, priority application of public housing, priority supply of public housing, preferential floor area ratio, funding, tax support, improvement of business area structure, improvement of delivery method, factory certification system, and training of experts. The results of the FGIs are as follows. First, in order to revitalize PC apartment homes, leading efforts from the public sector are required. Second, rather than reorganizing the business sector or introducing a new delivery method, a policy direction that induces the strengthening of cooperation is desirable. Third, PC activation should be promoted on an institutional basis for securing appropriate construction costs and quality.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.1
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• pp.139-146
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• 2021

This study studied the network between positive psychology capital, intention of start-up, and start-up behavior for learners who are willing to start a business. The research targets were intended to study the impact of the connection relationship between each variable, targeting nail art certification learners who are willing to start their own businesses. For this study, the measurement variables of positive psychology capital, intention of start-up, and start-up behavior were set, and the collected data were analyzed for connection-centeredness and eigenvector after data collection. The findings are as follows. First, some variables affecting the intention of start-up showed optimism, resilience and hope of positive psychology capital. Second, the intention to start a business was shown to have a significant impact on the behavior of start-ups, which, unlike the preceding study, appeared to be almost outside the network structure, showing that the behavior of start-ups was not significantly affected by other variables. Third, it is important to increase self-efficacy in positive psychological capital in order to increase the behavior of start-ups. Fourth, the analysis of the eigenvactor among positive psychology capital, intention of start-up, and start-up behavior showed optimism as some of the most central variables. In other words, prospective start-ups were found to be aware of the hardships and expected positive results in the future. The implications of this study, along with the intention and behavior of prospective entrepreneurs, are important factors in positive psychology capital, and suggest the importance of various educational programs that can be enhanced by positive psychology capital in start-up education or training programs and what should be taught. In addition, this study analyzed the network by approaching it from the perspective of positive psychology capital of prospective entrepreneurs in order to enhance the effectiveness of support programs for start-ups by the government, public institutions or universities in the future.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.81-99
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• 2022

The Baekdudaegan, spanning around 701 km from Hyangrobong to Cheonwangbong of Mt. Jirisan in South Korea, is rich in biodiversity and known as the main ecological axis of the Korean Peninsula. The Neuljae-Yuksimnyeong section of Marugeum in the southern part of the Baekdudaegan, particularly Mt. Deogyusan, is an area in which various types of vegetation appear depending on the environmental characteristics. The aims of this study were to investigate the current vegetation status at the Neuljae-Yuksimnyeong section of the Baekdudaegan and to provide basic data to aid systematic conservation and management through future classification of forest vegetation types. A vegetation survey was conducted using 637 plots from May to October 2019. Vegetation-type analysis showed that the vegetation units could be classified as a Quercus mongolica community group divided into seven communities: the Abies koreana community, Sanguisorba hakusanensis community, Persicaria hydropiper community, Quercus variabilis community, Quercus dentata community, Cornus controversa community, and Quercus mongolica community. The A. koreana community was subdivided into the Dryopteris expansa group and Picea jezoensis group. The Q. variabilis community was also subdivided into the Q. dentata group and Q. variabilis typical group. We concluded that special management plans for distinctive forest vegetation, including subalpine vegetation, grass or herb vegetation, and agricultural vegetation, should be prepared urgently to aid ecosystem preservation and enhancement.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.62-73
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• 2022

As the competition among the autonomous vehicle (AV, here after) developers are getting fierce, Korean government has been supporting developers by deregulating safety standards and providing financial subsidies. Recently, some OEMs announced their plans to market Lv3 and Lv4 automated driving systems. However, these market changes raised concern among public road management sectors for monitoring road conditions and alleviating hazardous conditions for AVs and human drivers. In this regards, the authors proposed a methodology for monitoring road infrastructure to identify hazardous factors for AVs and categorizing the hazards based on their level of impact. To evaluate the degrees of the harm on AVs, the authors suggested a methodology for managing road hazard factors based on vehicle performance features including vehicle body, sensors, and algorithms. Furthermore, they proposed a method providing AVs and road management authorities with potential risk information on road by delivering them on the monitoring map with node and link structure.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.1
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• pp.76-90
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• 2022

In this study, after applying the argument structure class design program for 20 preservice earth science teachers, we conducted individual in-depth interviews, analyzed the data, and derived a scientific argumentation PCK development model. The scientific argumentation PCK development model consists of three dimensions: Scientific argumentation PCK, PCK ecosystem, and reflective practice. Scientific argumentation PCK is demonstrated in the process of designing or executing classes using argumentation structures as an instructional reasoning tool. PCK ecosystem, consisting of the existing conventional PCK components, is a dimension surrounding the scientific argumentation PCK, and these two dimensions develop by interacting with each other. Reflective practice regulates each dimension and develops it in various ways by mediating the two dimensions of the scientific argumentation PCK and the PCK ecosystem. The conclusions drawn based on the results are as follows: First, preservice science teachers can demonstrate scientific argumentation PCK in the process of design and implementation of lessons using argumentation structures as a pedagogical reasoning tool. Second, it is necessary to develop the PCK for pedagogical reasoning tools such as scientific argumentation PCK in advance for the development of science teachers' PCK, since the scientific argumentation PCK can develop various components of the PCK ecosystem. Finally, it is necessary to use scientific argumentation PCK to support the preservice teacher's reflective practice, seeing that the scientific argumentation PCK promotes the development of PCK ecosystem components by inducing reflective practice.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.203-208
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• 2022

Recently, various digital technology issues such as e-Navigation, Maritime Autonomous Surface Ship (MASS) and Smart ships have constantly emerged in the maritime industry, based on the fourth industrial revolution. The International Maritime Organization is gradually tightening regulations for marine safety and marine environmental protection, and these strengthened regulations are leading to new maritime industries. Thus, the purpose of this study was to design a suitable model to analyze the industrial competitiveness of domestic autonomous operation technology industry, based on the Porter's diamond model. Based on a total of five evaluation factors and 13 detailed factors, the industrial competitiveness of the domestic autonomous operation technology industry was evaluated qualitatively and quantitatively. This industry, which is in the early stage of industrial development, was evaluated as 16.9 points relative to indexing industrial competitiveness. Currently, it is characterized by the simultaneous development of related regulations and core technologies, from the establishment of the scope of the industry. The industrial competitiveness evaluation considering these industrial characteristics is expected to serve as the basis for strategic support and new industrial policy, and impact a wide range of related industries such as shipping, logistics, ports, and shipbuilding and equipment industries.