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Scan Blindness Analysis of 1D and 2D Ka-Band Printed Dipole Array Antenna (일차원과 이차원 Ka-대역 프린티드 다이폴 배열 안테나의 스캔 블라인드니스 분석)

  • Koo, Hanni;Song, Sungchan;Nam, Sangwook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.3
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    • pp.202-208
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    • 2019
  • In this study, an active element pattern (AEP) of a printed dipole was analyzed in 1D and 2D arrays. First, an AEP of the printed dipole was obtained using the simulation in the 2D infinite array. The scan blindness in the 2D array occurred in the E-plane direction at around ${\pm}36^{\circ}$; however, it was barely observed in the 1D array. To analyze the cause of the scan blindness in the 2D array, the dispersion properties of a unit cell was obtained and compared with the scan blindness by frequency change. The difference between the scan blindness of the 1D and 2D arrays was clarified using the comparison of the Q value in the unit cell in the 1D and 2D arrays. Then, the coupling of the electric field in the E-plane direction was observed when nine elements were separated between the two ports in a linearly arranged dipole structure. Finally, the printed dipole array was fabricated, and an AEP was measured for the $11{\times}1$ and $11{\times}3$ sub arrays. The proposed theory was verified using these observations and by comparison with the simulation results.

A Study on Historical Research of Archetype of Kyeong Ju Castle (경주읍성 성곽시설의 원형고증에 관한 연구)

  • Kim, Hong Gon;Kim, Young Mo
    • Korean Journal of Heritage: History & Science
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    • v.43 no.2
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    • pp.4-39
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    • 2010
  • The purpose of this study is to examine the archetype of the Gyeongju Castle walls and the facilities around it to bring together previous studies and identify the specific scale and structure of the archetype. The findings can be summarized as follows. First, we verified the exact location and dimensions of the castle through an over-lay of land registration maps from the Japanese colonial period, land registration maps from the present day, cadastral maps, and excavation records. Second, the dimension of the rampart and fort of the castle were discovered by combining and analyzing historical evidence, modern research data, historical site studies from the Japanese colonial era, and maintenance records. Third, the historical records related to the yeojang (rampart sub-wall) formats in the Joseon Dynasty were used to examine the archetype of the yeojang. This study led to the discovery of the archetype of the Gyeongju castle yeojang in the early stage of King Munjong's reign (1451), and the archetype created after the Japanese Invasion (16th century). And finally, although most of the rampart is not present, the structure of the castle can be estimated based on historical research, and research materials modern and contemporary(excavation conservation field survey). In addition, this study presented a archetype restoration plan for each site, to be used as foundational data for future restoration projects.

Development of Site Evaluation Criteria for Woodland Burial Grounds (수목장림 입지 평가기준 설정 연구)

  • Moon, Chang Soon;Lee, ShiYoung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.3
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    • pp.22-30
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    • 2019
  • The demand for National Woodland Burial Grounds is expected to increase as interest in natural burial, including woodland burial, is increasing. This study was performed to provide evaluation criteria applying weighting factors to the evaluation for location selection. Through literature review, location selection evaluation factors for forest facilities, similar to forest welfare facilities, were reviewed and analyzed. As a result of the analysis, 74 preliminary evaluation criteria were selected. Based on the results, three expert groups (public servants in central and local governments and other public agencies in charge of forest welfare facility, related field researchers, and civil experts) reviewed the preliminary evaluation factors. Evaluation factors were classified into two categories, 6 sub-categories, and 22 segments. The selected evaluation factors were layered for the second preference survey. They were classified into Forest Environment and Human Environment, and those categories were further classified into three categories. Then they were further classified into segments. After segmentation, the experts who participated in the first survey checked the differences in the significance of the layered factors by utilizing AHP. The site evaluation criteria table was prepared using the evaluation criteria and the significance of each layer. In order to apply it to the candidate sites, 10 sites including the existing National Woodland Burial Grounds and 9 candidate sites considered in the previous studies were compared and analyzed including Ulju County Ulsan City, Suncheon City Jeollanam-do and Janggun-myeon Sejeong City.

Analysis of Teaching Practices of Mathematics Teachers from the Perspective of TPACK (수학교사의 테크놀로지 교수 내용 지식(TPACK) 관점에서 본 수업 실제 분석)

  • Lee, Da-Hee;Whang, Woo-Hyung
    • Journal of the Korean School Mathematics Society
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    • v.21 no.4
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    • pp.343-376
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    • 2018
  • The purpose of this study is to compare and analyze the perceptions of TPACK for mathematics teachers who practice the technology-using lessons. In addition, by looking at the part where the perception is expressed in the actual class and the part where the difference of recognition can be revealed, it is possible to provide the direction to teachers who want to practice the technology-using lessons in the future. To do this, two mathematics teachers were selected using purposeful sampling. And we conducted research study and interview in order to analyze the characteristics of the teacher's general background and TPACK recognition, and we analyzed the video, the class materials, and the interview contents for teaching practices from the perspective of TPACK. As a result, the two mathematics teachers practicing the technology-using lessons were connected with the actual class situation focusing on the sub-knowledges of TPACK recognizes as having a lot of them. In addition, technology-based lessons were able to confirm that the functional capabilities of technology alone were not sufficient conditions to lead effective instruction. Finally, teaching method using technology has been confirmed that experience-based field practice can be more important than simply knowing mathematics content, technology, teaching method. Based on the results of this study, it is possible not only to provide methodological guidance to teachers who practice the technology-based instruction, but also to suggest the direction of TPACK research or the development of teacher training program in the future.

The Effect of Marine Sport Event Visitors' Satisfactions and City Image on Revisit and Recommendation: Focusing on 2015 Busan Cup Women's International Match Race (해양스포츠 이벤트 관람자의 이미지, 만족도가 재방문 및 추천의도에 미치는 영향: 2015부산컵 세계여자매치레이스 요트대회를 중심으로)

  • Kim, Chan-Ryong;Lee, Jae Bin;Jang, Seung-Hyun
    • 한국체육학회지인문사회과학편
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    • v.56 no.1
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    • pp.53-65
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    • 2017
  • This study was conducted to examine how marine sport event visitors' satisfactions and city image effect on revisit and recommendation. To do this, we analyzed the socio-statistical characteristics of spectators, and examined the influence relationship among city image, satisfaction, revisit and recommendation intention. The results were as follows: First, 'family and relatives' as the companions of spectators of yacht competition were the most, and the route of acquiring the competition information was 'the other', in other words, that most of the respondents learned directly in the field, and 'car' as transportation means was the most. In addition, "local tourism" as watching purposes was the most and 'the day' as the period of stay was the most. Second, the image and satisfaction of spectators of yacht competition showed significant influence on revisit and recommendation intention. Specifically, program satisfaction and program agent satisfaction, which are a sub-factors of satisfaction, have a significant positive effect on revisit and recommendation intention. Through these research results, we were able to confirm inadequacy(lack of attractiveness, connections and public relations) of this event, and see what parts should be improved in order to be born again a sustainable event.

An Analysis of Dwelling Environment of Public Retirement(Silver) Housing Based on Post Occupancy Evaluation (거주 후 평가(P.O.E)에 의한 공공실버주택의 거주환경 분석)

  • Bak, Da-Hye;Kim, Young-Hwa;Lee, Sang-Hong
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.12
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    • pp.65-76
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    • 2018
  • Due to the rapid demographic and structural changes, Korea has faced a variety of social issues and quickly entered the aged society since the 2000s. In order deal with this reality, diverse types of welfare policies are emerging in the society as a whole. The government began to supply domestic public silver housing in 2016 to provide against the quickly growing aged society and now, the government is planning to supply approximately 50,000 housing by 2022 for quantitative growth of aged society, by selecting 1st and 2nd designated areas for the project additionally. This public retirement(silver) housing combines 'space' with 'service'. The lower floors are a public silver welfare Facilities and the upper floors are a housing spaces. This type of housing is to deal with requirements of rental housing residents by combining physical space with supporting service. Based on barrier-free design, the complex and unit house have safety handles and alarm bells in the bathroom, undulating washstands, bathroom sliding doors, corridor safety handles, and emergency safety exit lamps in each housing unit so the aged and the disabled can use easily and conveniently. Also, hand rails are installed and stepped pulleys are removed to promote convenience. Currently, the government is planning to increase the supply, focusing on low-income groups, such as beneficiaries of national basic livelihood and the working poor. Recognizing that the public retirement(silver) housing project is at its early stage, this study examined satisfaction, based on evaluations of real residents. This study aimed to obtain more empirical research data and apply them to public retirement(silver) house space analysis. For analysis, this study targeted Wirye public retirement(silver) housing and Magnolia public retirement(silver) housing that are in operation, and literature review, previous research review, and field survey were conducted to examine the present state. Using the questionnaires consisting of four large classification items; Block Layout, Housing Unit, Welfare Facilities, and Barrier-free Design, and sub-details, a survey was conducted to analyze residents' satisfaction. In conclusion, it is anticipated that this study would serve as basic research data about public retirement(silver) housing to increase continuously in future by analyzing public retirement(silver) housing spaces, on the basis of the analyzed data.

Preparation and Application of Cultivation Management Map Using Drone - Focused on Spring Chinese Cabbage - (드론 기반의 재배관리 지도 제작 및 활용방안 - 봄배추를 대상으로 -)

  • Na, Sang-il;Lee, Yun-ho;Ryu, Jae-Hyun;Lee, Dong-ho;Shin, Hyoung-sub;Kim, Seo-jun;Cho, Jaeil;Park, Jong-hwa;Ahn, Ho-yong;So, Kyu-ho;Lee, Kyung-do
    • Korean Journal of Remote Sensing
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    • v.37 no.3
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    • pp.637-648
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    • 2021
  • In order to support the establishment of a farming plan, it is important to preemptively evaluate crop changes and to provide precise information. Therefore, it is necessary to provide customized information suitable for decision-making by farming stage through scientific and continuous monitoring using drones. This study was carried out to support the establishment of the farming plan for ground vegetable. The cultivation management map of each information was obtained from preliminary study. Three cultivation management maps include 'field emergence map', 'stress map' and 'productivity map' reflected spatial variation in the plantation by providing information in units of plants based on 3-dimensions. Application fields of the cultivation management map can be summarized as follows: detect miss-planted, replanting decision, fertilization, weeding, pest control, irrigation schedule, market quality evaluation, harvest schedule, etc.

Development of a Self Balancing Electric Wheelbarrow (자기 균형 기능이 있는 외발 전동 손수레 개발)

  • Lee, Myung-Sub;Sung, Young-Whee
    • Journal of the Institute of Convergence Signal Processing
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    • v.21 no.1
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    • pp.21-28
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    • 2020
  • In this paper, a new type of electric wheelbarrow is proposed and developed. The developed electric wheelbarrow is equipped with an attitude reference system(ARS) sensor, which consists of 3-axis acceleration sensor and 2-axis Gyro sensor so that it can estimate pitch angle and roll angle. When an operator tilts the wheelbarrow up and down, the pitch angle is detected. The sign of the pitch angle is interpreted as the operator's intention for moving the wheelbarrow forward or backward and the controller drives the wheel of the wheelbarrow with the velocity according to the magnitude of the detected pitch angle. A cargo box of the wheelbarrow is designed to rotate and is controlled to maintain level always, so an operator can handle the electric wheelbarrow easily and safely. The wheelbarrow consists of an in-wheel motor, a DC motor, motor drives, an ARS sensor considering economical use in industrial field. Three experiments are performed to verify the feasibility and stability of the electric wheelbarrow.

Research Trends and Knowledge Structure of Digital Transformation in Fashion (패션 영역에서 디지털 전환 관련 연구동향 및 지식구조)

  • Choi, Yeong-Hyeon;Jeong, Jinha;Lee, Kyu-Hye
    • Journal of Digital Convergence
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    • v.19 no.3
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    • pp.319-329
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    • 2021
  • This study aims to investigate Korean fashion-related research trends and knowledge structures on digital transformation through information-based approaches. Accordingly, we first identified the current status of the relevant research in Korean academic literature by year and journal; subsequently, we derived key research topics through network analysis, and then analyzed major research trends and knowledge structures by time. From 2010 to 2020, we collected 159 studies published on Korean academic platforms, cleansed data through Python 3.7, and measured centrality and network implementation through NodeXL 1.0.1. The results are as follows: first, related research has been actively conducted since 2016, mainly concentrated in clothing and art areas. Second, the online platform, AR/VR, appeared as the most frequently mentioned topic, and consumer psychological analysis, marketing strategy suggestion, and case analysis were used as the main research methods. Through clustering, major research contents for each sub-major of clothing were derived. Third, major subject by period was considered, which has, over time, changed from consumer-centered research to strategy suggestion, and design development research of platforms or services. This study contributes to enhancing insight into the fashion field on digital transformation, and can be used as a basic research to design research on related topics.

Examining Economic Activities of Disabled People Using Media Big Data: Temporal Trends and Implications for Issue Detection (언론 빅데이터를 이용한 장애인 경제활동 분석: 키워드의 시기별 동향과 이슈 탐지를 위한 시사점)

  • Won, Dong Sub;Park, Han Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.548-557
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    • 2021
  • The purpose of this study was to determine the statistical usefulness of using atypical text data collected from media that are easy to collect to overcoming limits of the existing data related to economic activities of disabled people. In addition, by performing semantic network analysis, major issues by period that could not be grasped by statistical analysis were also identified. As a result, semantic network analysis revealed that the initiative of the public sector, such as the central and local government bodies, was strongly shown. On the other hand, in the private purchase sector, it was also possible to confirm the consumption revitalization trend and changes in production activities in the recent issue of Covid-19. While the term "priority purchase" had a statistically significant relation with the other two terms "vocational rehabilitation" and "employment for the disabled". For the regression results, while the term "priority purchase" had a statistically significant association with the other two terms "vocational rehabilitation" and "employment for the disabled". Further, some statistical analyses reveal that keyword data taken from media channels can serve as an alternative indicator. Implications for issue detection in the field of welfare economy for the disabled is also discussed.