• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.54-63
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• 2022

A 3-tonf class liquid rocket engine that powers the upper stage of a small launcher and lifts 500 kg payload to 500 km SSO is designed. The small launcher is to utilize the flight-proven technology of the 75-tonf class engine for the first stage. A combination of liquid oxygen and liquid methane has been selected as their cryogenic states can provide an extra boost in specific impulse as well as enable a weight saving via the common dome arrangement. An expander cycle is chosen among others as the low-pressure operation makes it robust and reliable while a specific impulse of over 360 seconds is achievable with the nozzle extension ratio of 120. Key components such as combustion chamber and turbopump are designed for additive manufacturing to a target cost. The engine system provides an evaporated methane for the autogenous pressurization system and the reaction control of the stage. This upper stage propulsion system can be extended to various missions including deep space exploration.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.1
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• pp.1-7
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• 2023

An artificial intelligence (AI) method based on image deep learning is proposed to predict the entire displacement shape of a structure using the feature of partial displacements. The performance of the method was investigated through a structural test of a steel frame. An image-to-image regression (I2IR) training method was developed based on the U-Net layer for image recognition. In the I2IR method, the U-Net is modified to generate images of entire displacement shapes when images of partial displacement shapes of structures are input to the AI network. Furthermore, the training of displacements combined with the location feature was developed so that nodal displacement values with corresponding nodal coordinates could be used in AI training. The proposed training methods can consider correlations between nodal displacements in 3D space, and the accuracy of displacement predictions is improved compared with artificial neural network training methods. Displacements of the steel frame were predicted during the structural tests using the proposed methods and compared with 3D scanning data of displacement shapes. The results show that the proposed AI prediction properly follows the measured displacements using 3D scanning.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.344-351
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• 2023

Purpose: This study aimed to evaluate the effectiveness of a dielectric barrier discharge (DBD) plasma module for sterilizing airborne bacteria in indoor spaces and measure the concentration of ozone generated during plasma discharge. Method: The DBD plasma module was installed in a 76m³ space, and air samples were collected under various discharge times to compare the reduction of airborne bacteria. Result: The results showed a significant decrease in airborne bacteria, ranging from 92.057% to 99.999%, with an average ozone concentration of 0.04 ppm, below the reference value. Conclusion: The study suggests that plasma discharge can be used as a means of preventing the spread of airborne bacteria and viruses, while ensuring safety for human exposure.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.25-40
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• 2007

Excessive earth pressure is one of the major mechanical factors in the deformation and damage of Cut-and-Cover Tunnel lining in shallow tunnels and portals of mountain tunnels (Kim, 2000). Excessive earth pressure may be attributed to insufficient compaction and consolidation of backfill material due to self-weight, precipitation and vibration caused by traffic (Komiya et al., 2000; Taylor et al., 1984; Yoo, 1997). Even though there were a lot of tests performed to determine the earth pressure acting on the tunnel lining, unfortunately there were almost no case histories of studies performed to determine remedial measures that reduce differential settlement and excessive earth pressure. In this study the installation of geotextile mat was selected to reduce the differential settlement and excessive earth pressure acting on the cut-and-cover tunnel lining. In order to determine settlement and earth pressure reduction effect (reinforcement effect) of geotextile mat reinforcement, laboratory tunnel model tests were performed. This study was limited to the modeling of rigid circular cut-and-cover tunnel constructed at a depth of $1.0D\sim1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. Model tests with varying soil cover, mat reinforcement scheme and slope roughness were performed to determine the most effective mat reinforcement scheme. Slope roughness was adjusted by attaching sandpaper #100, #400 and acetate on the cut slope surface. Mat reinforcement effect of each mat reinforcement scheme were presented by the comparison of earth pressure obtained from the unreinforced and mat reinforced model tests. Soil settlement reduction was analyzed and presented using the Picture Analysis Method (Park, 2003).

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.81-93
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• 2022

The purpose of this study is to understand the meaning of clinical practice experience, including web-based simulation practice, in the context of the corona pandemic era. As for the research method, data were collected through a focus group interview on the experience of web-based simulation practice and subsequent clinical practice and analyzed by content analysis method. The contents of the two interview groups were analyzed, and the results were divided into 2 components, 7 topic groups, and 18 topics. The first component, the clinical practice, was divided into four topic groups: 'The anxious start of practice in a pandemic situation', 'Direct experience through various cases', 'Training opportunities to prepare as a future nurse', and 'The burden of performance and limited experience'. The second component, the web-based simulation practice, was divided into three topic groups: 'Unfinished nursing practice', 'Indirect experience of clinical nursing in virtual space', and 'Requirement of an integrated practice model'. Clinical practice is a very important part of the nursing education curriculum. However, the nursing that students can perform in the field is very limited. Therefore, to supplement the shortcomings of observation-oriented clinical practice and to increase the quality of practical education, it is necessary to consider a hybrid education model including web-based simulation practice.

• Journal of Popular Narrative
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• v.25 no.4
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• pp.73-108
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• 2019

This paper is an attempt to discuss the history and the current state of 'SF theaters.' SF theater is still an unfamiliar genre to the public, and may surprise some, given that the stage is perceived as an insufficient space for stretching the scientific imagination. Since 2010 works that bring the scientific imagination into the theater have frequently been performed, and a recognition of SF theaters began to be established. Producers came to be absorbed in human psychology, and our isolation amidst the progress in technology, as well as in the absurdities of the world, while giving up the ideal of realistic descriptions. This became the foundation for SF theaters in South Korea today. Starting from the research history and the conceptual change in SF theaters, this study examined the status of SF dramas going back to the colonial period for SF theaters. Through inquiring into the history of SF theaters, we were able to derive the following implications and problems. Firstly, as they are based on future society or technical improvement without consideration of scientific probability or rationality, the scientific imagination is too absent for the work to be named 'SF theater.' Secondly, while being highly evaluated as an attempt to integrate science and stage in an era that emphasizes convergence, when we delve into the creativity of a material it is noticeable that the view of the world is still regressive. Thirdly, there are many cases in which scripts lean on SF classics or Japanese original works. Nevertheless, if young creators' diverse attempts in a genre can breathe with the contemporary audience desiring a new material, the foundation of a Korean-style SF theater may be expanded to include more significant work.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.63-72
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• 2017

This study made of centrally actual application in general arts classes based on movie in university. Especially, I analyzed the activities of the class with 'Untouchable: 1% friendship' among 6 films. The objects of this study are 44 students of D university in Busan Metropolitan City who take 'creative fusion from movie' general arts class which opened first semester in 2016. In this study, students were able to watch movies through the creative class, which was out of the traditional classroom method, and after 15 hours of learning the quiz online, they conducted 15 weeks as a teaching method to perform tasks, presentations, experiments, and experiences in regular class time. The results of this study are as follows. 'It is a general arts class that makes movements live,' 'It is a general arts class that shows movies from various perspectives,' and 'It is a general arts class that makes me know.' This suggests that the educational medium, which is easily accessible in everyday life, and the general arts class, which is active in the space outside the framework, are perceived as stimulating curiosity and adding fun to college students.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.1
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• pp.1-16
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• 2018

A residential space where a person lives in may change following the flow of time and it has evolved in various shapes through the development process of a city. In particular, after the 1900s when the modern urban planning was first applied in full-scale, the urban environment and residential environment have formed cities through systematic planning. Under the assumption that the level of satisfactory life for urban residents residing in such an urban environment would be influenced mutually with the residential environment and urban environment to carry out this study, and as for the methodology of this study, the questionnaire was implemented with the subject of residents in Seoul City and analysis was implemented for regression analysis through SPSS 20.0 program. The results of the study are shown as follows. First, the relationship of the residential environment and urban environment is classified for convenience, safety and pleasance to have the important implication, and the level of satisfaction for the residential environment is analyzed to show implications with influence on the level of satisfaction for settlement consciousness. Second, the relationship of influence of residential environment on the settlement consciousness with the characteristics of urban environment is statistically noticeable and the stability and pleasance would have the statistically noticeable influence on satisfactory residential environment and the convenience would not render noticeable influence. And, third, under the characteristics of urban environment, convenience does not have direct influence on the settlement consciousness and it is confirmed to influence on the settlement consciousness indirectly only through the satisfaction of variation in the residential environment.

• Design Convergence Study
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• v.15 no.1
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• pp.135-150
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• 2016

Due to the development of communication technology and expansion of Intelligent Transport System (ITS), the car is changing from a simple mechanical device to second living space which has comprehensive convenience function and is evolved into the platform which is playing as an interface for this role. As the interface area to provide various information to the passenger is being expanded, the research importance about smart car based user experience is rising. This study has a research objective to propose the guidelines regarding the smart car user experience elements. In order to conduct this study, smart car user experience elements were defined as function, interaction, and surface and through the discussions of UX/UI experts, 8 representative techniques, 14 representative techniques, and 8 locations of the glass windows were specified for each element. Following, the smart car users' priorities of the experience elements, which were defined through targeting 100 drivers, were analyzed in the form of questionnaire survey. The analysis showed that the users' priorities in applying the main techniques were in the order of safety, distance, and sensibility. The priorities of the production method were in the order of voice recognition, touch, gesture, physical button, and eye tracking. Furthermore, regarding the glass window locations, users prioritized the front of the driver's seat to the back. According to the demographic analysis on gender, there were no significant differences except for two functions. Therefore this showed that the guidelines of male and female can be commonly applied. Through user requirement analysis about individual elements, this study provides the guides about the requirement in each element to be applied to commercialized product with priority.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.9
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• pp.833-840
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• 2017

This study was attempted to explore in depth the education of cultural diversity in the curriculum and textbooks of middle school according to [1] As a result, the educational goals in the curriculum emphasized[2] the realization of the meaning and value of cultural diversity education reflecting the global citizen education in various time, space background and socio-cultural context. The purpose of the curriculum guidelines is specified, and the following is given: "To properly recognize the diversity of the world culture; To acquire knowledge on cultural diversity; To grasp important functions in the city life, and to have attitudes and qualities required as members of the world, and to develop a pluralistic literacy ability''. In the textbooks, the subjects of the cultural diversity education are mainly based on the curriculum standards, the education area of the 7th grade is the 'human community life', the education area of the 8th grade is the origin and development of the Chinese civilization, Suggesting the scope of the theme 'harmonious coexistence with the world'. In order to analyze cultural diversity education in response to the demands of the times, we analyzed three factors such as diversity, identity, and interrelationship.