• Title/Summary/Keyword: 공간영역

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Ultra-high Temperature EM Wave Absorption Behavior for Ceramic/Sendust-aluminosilicate Composite in X-band (X-Band 영역에서의 세라믹/샌더스트-알루미노실리케이트 복합재의 초고온 전자파 흡수 거동)

  • Choi, Kwang-Sik;Sim, Dongyoung;Choi, Wonwoo;Shin, Joon-Hyung;Nam, Young-Woo
    • Composites Research
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    • v.35 no.3
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    • pp.201-215
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    • 2022
  • This paper presents the development of thin and lightweight ultra-high temperature radar-absorbing ceramic composites composed of an aluminosilicate ceramic matrix-based geopolymer reinforced ceramic fiber and sendust magnetic nanoparticles in X-band frequency range (8.2~12.4 GHz). The dielectric properties with regard to complex permittivity of ceramic/sendust-aluminosilicate composites were proportional to the size of sendust magnetic nanoparticle with high magnetic characteristic properties as flake shape and its concentrations in the target frequency range. The characteristic microstructures, element composition, phase identification, and thermal stability were examined by SEM, EDS, VSM and TGA, respectively. The fabricated total thicknesses of the proposed single slab ultra-high temperature radar absorber correspond to 1.585 mm, respectively, exhibiting their excellent EM absorption performance. The behavior of ultra-high temperature EM wave absorption properties was verified to the developed free-space measurement system linked with high temperature furnace for X-band from 25℃ to 1,000℃.

The Effect of Ground Heterogeneity on the GPR Signal: Numerical Analysis (지반의 불균질성이 GPR탐사 신호에 미치는 영향에 대한 수치해석적 분석)

  • Lee, Sangyun;Song, Ki-il;Ryu, Heehwan;Kang, Kyungnam
    • Journal of the Korean GEO-environmental Society
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    • v.23 no.8
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    • pp.29-36
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    • 2022
  • The importance of subsurface information is becoming crucial in urban area due to increase of underground construction. The position of underground facilities should be identified precisely before excavation work. Geophyiscal exporation method such as ground penetration radar (GPR) can be useful to investigate the subsurface facilities. GPR transmits electromagnetic waves to the ground and analyzes the reflected signals to determine the location and depth of subsurface facilities. Unfortunately, the readability of GPR signal is not favorable. To overcome this deficiency and automate the GPR signal processing, deep learning technique has been introduced recently. The accuracy of deep learning model can be improved with abundant training data. The ground is inherently heteorogeneous and the spacially variable ground properties can affact on the GPR signal. However, the effect of ground heterogeneity on the GPR signal has yet to be fully investigated. In this study, ground heterogeneity is simulated based on the fractal theory and GPR simulation is carried out by using gprMax. It is found that as the fractal dimension increases exceed 2.0, the error of fitting parameter reduces significantly. And the range of water content should be less than 0.14 to secure the validity of analysis.

Focus Group Interview(FGI) Study on 'K-Edu' Experienced by School Teachers In COVID19 (코로나19에 대응하며 현장교사들이 경험한 'K-교육'에 대한 FGI(Focus Group Interview) 연구)

  • Choi, Sung-Kwang;Choi, Mi-Jung
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.2
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    • pp.179-189
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    • 2021
  • As the school was in crisis due to the COVID-19, e-Learning was extended. Although it was difficult for everyone, e-Learning were stabilized with the enthusiasm and efforts of school teachers. Online education in Korea, called 'K-edu' is being promoted by school teachers in COVID19, and is considered an important area of future education beyond the post corona. Therefore, analyze the meaning of K-edu experienced by school teachers, studying changes in the educational paradigm in the Post-COVID era is very important in establishing the direction and content of future education. In this study described the K-edu experienced by school teachers in response to Corona 19 as 'changed daily life of school teachers', 'changes in schools', 'difficulties felt by teachers' and 'proposals for K-edu' through the qualitative research method FGI. Based on this, the characteristics of K-edu that changed through COVID-19 were analyzed as 'expansion of educational space', 'expansion of educational form' and 'highlighting the importance of face-to-face education'. Through this study, we hope that K-Edu led by school teachers will serve as a cornerstone for leading the world beyond Korea.

A Study on AI Algorithm that can be used to Arts Exhibition : Focusing on the Development and Evaluation of the Chatbot Model (예술 전시에 활용 가능한 AI 알고리즘 연구 : 챗봇 모델 개발 및 평가를 중심으로)

  • Choi, Hak-Hyeon;Yoon, Mi-Ra
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.4
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    • pp.369-381
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    • 2021
  • Artificial Intelligence(AI) technology can be used in arts exhibitions ranging from planning exhibitions, filed progress, and evaluation. AI has been expanded its scope from planning exhibition and guidance services to tools for creating arts. This paper focuses on chatbots that utilize exhibition and AI technology convergence to provide information and services. To study more specifically, I developed a chatbot for exhibition services using the Naver Clova chatbot tool and information from the National Museum of Modern and Contemporary Art(MMCA), Korea. In this study, information was limited to viewing and exhibition rather than all information of the MMCA, and the chatbot was developed which provides a scenario type to get an answering user want to gain through a button and a text question and answer(Q&A) type to directly input a question. As a result of evaluating the chatbot with six items according to ELIZA's chatbot evaluation scale, a score of 4.2 out of 5 was derived by completing the development of a chatbot to be used to deliver viewing and exhibition information. The future research task is to create a perfect chatbot model that can be used in an actual arts exhibition space by connecting the developed chatbot with continuous scenario answers, resolving text Q&A-type answer failures and errors, and expanding additional services.

Analysis of Albedo by Level-2 Land Use Using VIIRS and MODIS Data (VIIRS와 MODIS 자료를 활용한 중분류 토지이용별 알베도 분석)

  • Lee, Yonggwan;Chung, Jeehun;Jang, Wonjin;Kim, Jinuk;Kim, Seongjoon
    • Korean Journal of Remote Sensing
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    • v.38 no.6_1
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    • pp.1385-1394
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    • 2022
  • This study was to analyze the change in albedo by level-2 land cover map for 20 years(2002-2021) using MODerate resolution Imaging Spectroradiometer (MODIS) data. Also, the difference from the MODIS data was analyzed using the 10-year (2012-2021) data of Visible Infrared Imaging Radiometer Suite (VIIRS). For the albedo data of MODIS and VIIRS, daily albedo data, MCD43A3 and VNP43IA, of 500 m spatial resolution of sinusoidal tile grid produced by Bidirectional Reflectance Distribution Function (BRDF) model were prepared for the South Korea range. Reprojection was performed using the code written based on Python 3.9, and the nearest neighbor was applied as the resampling method. White sky albedo and black sky albedo of shortwave were used for analysis. As a result of 20-year albedo analysis using MODIS data, the albedo tends to rise in all land use. Compared to the 2000s (2002-2011), the average albedo of the 2010s (2012-2021) showed the most significant increase of 0.0027 in the forest area, followed by the grass increase of 0.0024. As a result of comparing the albedo of VIIRS and MODIS, it was found that the albedo of VIIRS was larger from 0.001 to 0.1, which was considered to be due to differences in the surface reflectivity according to the time of image capture and sensor characteristics.

A Study on the Development of H2 Fuel Cell Education Platform: Meta-Fuelcell (연료전지 교육 플랫폼 Meta-Fuelcell 개발에 관한 연구)

  • Duong, Thuy Trang;Gwak, Kyung-Min;Shin, Hyun-Jun;Rho, Young-J.
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.22 no.5
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    • pp.29-35
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    • 2022
  • This paper proposes a fuel cell education framework installed on a Metaverse environment, which is to reduce the burden of education costs and improve the effect of education or learning. This Meta-Fuel cell platform utilizes the Unity 3D Web and enables not only theoretical education but also hands-on training. The platform was designed and developed to accommodate a variety of unit education contents, such as ppt documents, videos, etc. The platform, therdore, integrates ppt and video demonstrations for theoretical education, as well as software content "STACK-Up" for hands-on training. Theoretical education section provides specialized liberal arts knowledge on hydrogen, including renewable energy, hydrogen economy, and fuel cells. The software "STACK-Up" provides a hands-on practice on assembling the stack parts. Stack is the very core component of fuel cells. The Meta-Fuelcell platform improves the limitations of face-to-face education. It provides educators with the opportunities of non-face-to-face education without restrictions such as educational place, time, and occupancy. On the other hand, learners can choose educational themes, order, etc. It provides educators and learners with interesting experiences to be active in the metaverse space. This platform is being applied experimentally to a education project which is to develop advanced manpower in the fuel cell industry. Its improvement is in progress.

Analysis of Built and Walking Environment for Coastal Ferry Terminal using IPA -Focusing on Yeosu Coastal Ferry Terminal- (IPA를 이용한 연안여객터미널의 시설 및 보행특성 분석 -여수연안여객터미널을 중심으로-)

  • Song, Tea-Han;Kim, Hwa-Young
    • Journal of Korea Port Economic Association
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    • v.37 no.3
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    • pp.93-104
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    • 2021
  • A coastal ferries, which serve as a mode between mainland and offshore islands, are frequently used by islanders and travelers visiting islands. Therefore, it is located in a place with good accessibility to the downtown so that users can use it conveniently. However, research on the built environment and walking environment of coastal ferry terminals has not been conducted to ensure that elderly islanders and general travelers can use comfortably the coastal ferry terminal. In this study, with a focus on the coastal ferry terminal space, the walking section was set as 1)the accessibility of the coastal ferry terminal, 2)the built environment for using the coastal ferry terminal, and 3)walking environment in the ferry boarding and disembarkation at the coastal ferry terminal, and 4, 5)walking environment in the ferry. An evaluation tool was developed to measure the walking environment for each walking section, and the importance and satisfaction of users were analyzed using the IPA for the Yeosu Coastal Ferry Terminal. As a result, in the process of approaching the ferry terminal, 'convenience of using public transportation by foot' and 'convenience of using signposts guiding the location and direction of the ferry terminal' were investigated as concentrated areas. On the other hand, the built environment inside the ferry terminal and the walking environment showed that the satisfaction of the users was high. Regarding the walking environment from the ferry terminal to the ferry, the 'surface walking environment of the walking path', 'convenience of walking with luggage', 'convenience of walking in the slope section', and 'convenience of walking in the ferry ramp section' showed low satisfaction. This study can be used as basic data for improving the facilities and walking environment of Yeosu Coastal Ferry Terminal and is expected to be used as data for comparative research with other coastal ferry terminals.

Evaluation of vegetation index accuracy based on drone optical sensor (드론 광학센서 기반의 식생지수 정확도 평가)

  • Lee, Geun Sang;Cho, Gi Sung;Hwang, Jee Wook;Kim, Pyoung Kwon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.2
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    • pp.135-144
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    • 2022
  • Since vegetation provides humans with various ecological spaces and is also very important in terms of water resources and climatic environment, many vegetation monitoring studies using vegetation indexes based on near infrared sensors have been conducted. Therefore, if the near infrared sensor is not provided, the vegetation monitoring study has a practical problem. In this study, to improve this problem, the NDVI (Normalized Difference Vegetation Index) was used as a reference to evaluate the accuracy of the vegetation index based on the optical sensor. First, the Kappa coefficient was calculated by overlapping the vegetation survey point surveyed in the field with the NDVI. As a result, the vegetation area with a threshold value of 0.6 or higher, which has the highest Kappa coefficient of 0.930, was evaluated based on optical sensor based vegetation index accuracy. It could be selected as standard data. As a result of selecting NDVI as reference data and comparing with vegetation index based on optical sensor, the Kappa coefficients at the threshold values of 0.04, 0.08, and 0.30 or higher were the highest, 0.713, 0.713, and 0.828, respectively. In particular, in the case of the RGBVI (Red Green Red Vegetation Index), the Kappa coefficient was high at 0.828. Therefore, it was found that the vegetation monitoring study using the optical sensor is possible even in environments where the near infrared sensor is not available.

A Study on Application of Archival Information Services Based on Metaverse (메타버스 기반 기록정보서비스 적용 방안 연구)

  • Kim, Hyunjin;Yim, Jinhee
    • The Korean Journal of Archival Studies
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    • no.74
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    • pp.119-153
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    • 2022
  • Metaverse combines the real and virtual worlds to create a world where all experiences and activities in the real world are possible even in the virtual world without time and space constraints. Currently, metaverse technology is expanding and converging into the realms of society, economy, and culture. In particular, the MZ generation, the main user base, is engaged in various cultural activities such as games, contents, culture, exhibitions, and performances in the metaverse world. Archives, one of the cultural institutions, should provide a new type of service by fusion of Archival information services with metaverse technology so that the MZ generation can know the value and meaning of archives. This will arouse the interest of the MZ generation, which will naturally increase the awareness of the archives, increase visits and use, and will serve as an opportunity to expand the user base. Therefore, in this study, the concept, type, and characteristics of each service were examined, and the representative metaverse platform for each service was selected and a platform utilization plan suitable for Archival information services such as exhibition, experience, and publicity was proposed. In addition, by using 'Spatial', a blockchain-based social metaverse platform, to directly produce exhibition contents, we want to check the considerations suggested, the production process, and the advantages of the metaverse exhibition.

Suggestions for Developing a Metaverse Platform for Educational Purpose: A Delphi Study

  • Hee Chul, Kim;Iljun, Park;Myoeun, Kim
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.2
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    • pp.235-246
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    • 2023
  • In this paper, we propose suggestions for developing a Metaverse platform for educational purpose utilizing a Delphi study method with experts on Metaverse and digital education. 17 experts participated in the 1st study and 16 took part in the 2nd study, and data was collected via emails from January 5th to 10th for the 1st study and from January 12th to 17th for the 2nd study in 2022. Collected data in the 1st study was analyzed by applying content analysis. The results for the 1st study indicated that there were 120 sub-factors were derived from 7 main questions(the necessity of a Metaverse platform for future education, how to use the Metaverse platform for education to improve the capacities needed for future human resources, problems that may arise during education using the Metaverse platform, the functions that the Metaverse platform for education should have, the infrastructure and environment required when using the Metaverse platform for education, how to use the Metaverse effectively as a learning space, subjects and educational contents that will be effective if conducted on the Metaverse platform for education). The results for the 2nd study were presented by being ranked with calculated means of sub-factors for each question. Finally, based on the results, suggestions for building a Metaverse platform for educational purpose are stated and limitations of the study and possible future study are discussed.