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Analysis of Cable Protection of Duct in Lightning and HIRF Environment of UAM Aircraft and a Proposal for Certification Guidance (UAM 항공기 낙뢰 및 HIRF 환경에서 덕트의 케이블 보호 성능 분석 및 인증기술에 관한 연구)

  • Kim, Dong-Hyeon;Jo, Jae-Hyeon;Kim, Yun-Gon;Lee, Hakjin;Myong, Rho-Shin
    • Journal of Aerospace System Engineering
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    • v.16 no.3
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    • pp.23-34
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    • 2022
  • Cities around the world are increasing their demand for Urban Air Mobility (UAM) aircraft due to traffic congestion with population concentration. Aircraft with various shapes depending on fixed-wing and propulsion systems, are being prepared for commercialization. Airworthiness certification is required as it is a manned transportation vehicle that flies in the city center and transports people on board. UAM aircraft are vulnerable to lightning and HIRF environments due to the increasing use of composite materials, the use of electric motors, and use of electronic equipment. Currently, the development of certification technology, guidelines, and requirements in lightning and HIRF environments for UAM aircraft is incomplete. In this study, the certification procedures for lightning and HIRF indirect impacts of rotorcraft shown in AC 20-136B and AC 20-158A issued by the Federal Aviation Administration (FAA), were verified and applied to the computerized simulation of UAM aircraft. The impact of lightning and HIRF on ducted fan UAM aircraft was analyzed through computerized simulation, and the basis for establishing practical guidelines for certification of UAM aircraft to be operated in the future is presented.

A Study on Building Object Change Detection using Spatial Information - Building DB based on Road Name Address - (기구축 공간정보를 활용한 건물객체 변화 탐지 연구 - 도로명주소건물DB 중심으로 -)

  • Lee, Insu;Yeon, Sunghyun;Jeong, Hohyun
    • Journal of Cadastre & Land InformatiX
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    • v.52 no.1
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    • pp.105-118
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    • 2022
  • The demand for information related to 3D spatial objects model in metaverse, smart cities, digital twins, autonomous vehicles, urban air mobility will be increased. 3D model construction for spatial objects is possible with various equipments such as satellite-, aerial-, ground platforms and technologies such as modeling, artificial intelligence, image matching. However, it is not easy to quickly detect and convert spatial objects that need updating. In this study, based on spatial information (features) and attributes, using matching elements such as address code, number of floors, building name, and area, the converged building DB and the detected building DB are constructed. Both to support above and to verify the suitability of object selection that needs to be updated, one system prototype was developed. When constructing the converged building DB, the convergence of spatial information and attributes was impossible or failed in some buildings, and the matching rate was low at about 80%. It is believed that this is due to omitting of attributes about many building objects, especially in the pilot test area. This system prototype will support the establishment of an efficient drone shooting plan for the rapid update of 3D spatial objects, thereby preventing duplication and unnecessary construction of spatial objects, thereby greatly contributing to object improvement and cost reduction.

A Study on the Status and Gap Analysis of Public Library in Chungcheongnam-do (충청남도 공공도서관 현황 및 격차 분석 연구)

  • Oh, Seon-Kyung
    • Journal of Korean Library and Information Science Society
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    • v.53 no.2
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    • pp.215-239
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    • 2022
  • All public libraries are local public goods and cultural infrastructures whose ideological pillars are publicly operated, free, and open to all. This identity is justified when the public library provides various knowledge information, various programs, and community space to local residents within the service area, and ultimately contributes to the cultural development of the nation and society. To this end, the country and local governments must expand the number of individuals that meet legal standards, deploy competent professionals, and provide facilities and spaces that are easy to access and use. However, if there is a gap in infrastructure and services between regional public libraries, it causes inequality in access and use of residents, which inevitably leads to information gap and cultural welfare gap. Therefore, this study was analyzed the relative gap using the location quotient, key infrastructure indicators and service indicators of public libraries of regional government in Korea and basic local government in the Chungnam region from the viewpoint that the balanced development and capacity building of public libraries must precede the establishment of a public library in Chungnam region as a life-friendly knowledge information service institution, culture enjoyment and lifelong learning space. Based on the results, a method to resolve the gap was suggested by dividing the elements of gaps in public libraries into accessibility, core infrastructure, and services, focusing on vulnerable cities and counties in the Chungnam region.

Evaluation of Debonding Defects in Railway Concrete Slabs Using Shear Wave Tomography (전단파 토모그래피를 활용한 철도 콘크리트 궤도 슬래브 층분리 결함 평가)

  • Lee, Jin-Wook;Kee, Seong-Hoon;Lee, Kang Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.3
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    • pp.11-20
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    • 2022
  • The main purpose of this study is to investigate the applicability of the shear wave tomography technology as a non-destructive testing method to evaluate the debonding between the track concrete layer (TCL) and the hydraulically stabilized based course (HSB) of concrete slab tracks for the Korea high-speed railway system. A commercially available multi-channel shear wave measurement device (MIRA) is used to evaluate debonding defects in full-scaled mock-up test specimen that was designed and constructed according to the Rheda 200 system. A part of the mock-up specimen includes two artificial debonding defects with a length and a width of 400mm and thicknesses of 5mm and 10mm, respectively. The tomography images obtained by a MIRA on the surface of the concrete specimens are effective for visualizing the debonding defects in concrete. In this study, a simple image processing method is proposed to suppress the noisy signals reflected from the embedded items (reinforcing steel, precast sleeper, insert, etc.) in TCL, which significantly improves the readability of debonding defects in shear wave tomography images. Results show that debonding maps constructed in this study are effective for visualizing the spatial distribution and the depths of the debondiing defects in the railway concrete slab specimen.

Epidemiological investigation of porcine pseudorabies virus and its coinfection rate in Shandong Province in China from 2015 to 2018

  • Ma, Zicheng;Han, Zifeng;Liu, Zhaohu;Meng, Fanliang;Wang, Hongyu;Cao, Longlong;Li, Yan;Jiao, Qiulin;Liu, Sidang;Liu, Mengda
    • Journal of Veterinary Science
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    • v.21 no.3
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    • pp.36.1-36.9
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    • 2020
  • Background: Pseudorabies, also known as Aujeszky's disease, is caused by the pseudorabies virus (PRV) and has been recognized as a critical disease affecting the pig industry and a wide range of animals around the world, resulting in great economic losses each year. Shandong province, one of the most vital food animal-breeding regions in China, has a very dense pig population, within which pseudorabies infections were detected in recent years. The data, however, on PRV epidemiology and coinfection rates of PRV with other major swine diseases is sparse. Objectives: This study aimed to investigate the PRV epidemiology in Shandong and analyze the current control measures. Methods: In this study, a total number of 16,457 serum samples and 1,638 tissue samples, which were collected from 362 intensive pig farms (≥ 300 sows/farm) covered all cities in Shandong, were tested by performing enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Results: Overall, 52.7% and 91.5% of the serum samples were positive for PRV-gE and -gB, respectively, based on ELISA results. In addition, 15.7% of the tissue samples were PCR positive for PRV. The coinfection rates of PRV with porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus, and classical swine fever virus were measured; coinfection with PCV2 was 35.0%, higher than those of the other two viruses. Macroscopic and microscopic lesions were observed in various tissues during histopathological examination. Conclusions: The results demonstrate the PRV prevalence and its coinfection rates in Shandong province and indicate that pseudorabies is endemic in pig farms in this region. This study provides epidemiological data that can be useful in the prevention and control of pseudorabies in Shandong, China.

A Study on Facility Changes according to Changes in the Urban Park Type in Korea - Focus on Parks in Seoul - (국내 도시공원 유형변경에 따른 시설변화 연구 - 서울시 공원을 중심으로 -)

  • Ko, Ha-jung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.50 no.2
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    • pp.76-88
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    • 2022
  • Urban parks play the role of providing leisure spaces for people in their everyday life along with serving ecological functions in the city. Although urban parks aim to satisfy the needs of users visiting the park, most urban parks are currently uniformly created and maintained without considering the environmental characteristics based on the needs of users. This study thus analyzed parks that underwent modifications in line with the revised Park Act in 2005. There were 45 parks whose types were legally changed, of which 21 were changed from children's parks to small parks, and 19 were changed to utilize and highlight the themes such as cultural parks and historical parks. Among the parks whose types have changed, the ratio of amenities in cultural and historic parks has increased, while the facility area in small parks has decreased and the green area has increased in its place. As a result of analyzing the changes to the park facility area, it was confirmed that increasing park amenities has a positive effect in pursuing revitalization of use through park maintenance, but has a negative consequence of significantly decreasing green area. It is necessary to reorganize the park type classification system to reflect the park environment and prepare guidelines for a new installation standard by park type to expand the net function of parks in cities and maintain the sustainable ecological environment. Through in-depth discussions on the facilities of park types, it is anticipated that innovative and multilateral research could be conducted to prepare improvement measures tailored to the guidelines of urban park types in years to come.

Searching for the Policy Alternatives for the Activation of the Local Culture Industry in Korea (지역문화산업의 활성화를 위한 정책 대안의 모색)

  • Kwon, Young-Gil
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.7
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    • pp.175-191
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    • 2020
  • The purpose of this study is to find out the policy alternatives for the activation of the local culture industry in Korea. The research methodology is content analysis into law articles of local culture promotion act and framework act on the promotion of culture industries and some related acts, to review the relations between local culture promotion and the promotion of culture industries. The results of this study are the followings: Firstly, the policies for the promotion of culture industries should connect to the policies of local culture promotion. 1) Local culture industries are related with the facilities like living cultural centers and the activities of the arts organizations or clubs of residents. 2) The industrial condiitions should be considered in the process of designation of cutural city and cultural area. 3) The local cuture industry policies should be connected to raise the funds for local culture promotion. 4) The local culture industries should be connected to the cultivation of professional personnel for local cultural promotion. Secondly, for the activation of the local culture industries, the obstructive factors should be eliminated and the facilitating factors should be utilized. 1) The purpose of the culture industries should be defined as concrete and clear through the clearly prescribing the range of culrure industries. 2) The roles which have been dispersed to various agents should assigned as designated clealy and the cooperative system should be construced. 3) In designating cultural cities and cultural area, conceptual elements should be considered and the brand of the local culrure industries should be presented. 4) The background industries such as tourism industries should be utilized. 5) Governance systems should be constructed and utilized.

Public Policy Research on Maker Cultre: the case of Makercity Sewoon (메이커문화를 대상으로 한 공공정책 연구 - '메이커시티 세운'을 중심으로 -)

  • Oh, Kyoungmi;Park, Sohyun
    • Korean Association of Arts Management
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    • no.56
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    • pp.243-274
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    • 2020
  • Maker culture in Korea began to receive public attention after the 2012 Maker Fair Seoul. Central and local governments took note of this trend and subsumed makers' culture into its policy domains such as Creative Industry, Creative Cities, 4th Industrial Revolution, and the all-encompassing Creative Economy. Creative Economy was a public policy discourse formed in the public sector for the purpose of overcoming economic depression and revitalizing the economy. Under Creative Industry and Creative Economy, creativity and culture/arts are deemed indispensable but at the same time objectified and alienated as their ultimate value are recognized only as the basis for economic production. In this article, makers' culture itself goes through the same process of objectification and alienation that creativity and culture/arts suffered as the relevant policies were pursued under Creative Economy. The authors attempted to corroborate this through the case of Makercity Sewoon, and found that the Seoul City's urban development plan surrounding Sewoon Plaza proceeded in a direction destructive to the local technological ecosystem and therefore conflicts with the pronounced goal of leading 4th Industrial Revolution by encouraging and nurturing makers' culture. Makercity Sewoon, although packaged in a discourse of Creative Economy and Creative City, betrayed the same problem of alienating arts/culture and labor that the previous discourse showed.

A Study on Mitigation Plan of Urban Heat Island Phenomenon Using Landsat Time Series Imagery - Focusing on Cheongna International City - (시계열 Landsat 위성영상을 활용한 도시 열섬 현상 완화 방안에 관한 연구 - 청라 국제도시를 중심으로 -)

  • BAEK, Seon-Uk;KIM, Dong-Hyun;KIM, Hung-Soo;GU, Bon-Yup;CHOUNG, Yun-Jae
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.3
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    • pp.1-16
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    • 2022
  • Areas developed through land reclamation projects have huge economic advantages in terms of supplying lands that can be used for farmlands, urban areas and etc., however have relatively small areas of grasslands and densely located buildings compared to inland cities. Hence, an urban heat island is occurring in these areas due to this characteristic, and in particular, the urban heat island in Cheongna International City is getting serious. In this study, the urban heat island in Cheongna International City was evaluated and analyzed by classified into the three periods after the reclamation project: farmland(2001-2008), development(2009-2013) and artificial grassland(2014-2020). The land cover map and Landsat time-series imagery were utilized for measuring the differences of the land surface temperatures between the urbanized areas and the grassland/forest areas in Cheongna International City. The statistical results showed that the differences in the land surface temperature between these areas were calculated to be at most 0℃ during the period of farmland, at most 3.60℃ during the period of development, and at most 2.51℃ during the period of grassland. This study proved that the urban heat island phenomenon increased when the urbanized areas increased, and the urban heat island phenomenon decreased when the artificial grassland areas increased in Cheongna International City where the reclamation project was carried out. The statistical results derived through this research can be used as the reference data for identifying the urban heat island problem in urban planning and establishing the reduction plan.

Effect of Total Resistance of Electrochemical Cell on Electrochemical Impedance of Reinforced Concrete Using a Three-Electrode System (3전극방식을 활용한 철근 콘크리트의 교류임피던스 측정 시 전기화학 셀저항의 영향)

  • Khan, Md. Al-Masrur;Kim, Je-Kyoung;Yee, Jurng-Jae;Kee, Seong-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.6
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    • pp.82-92
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    • 2022
  • This study aims to investigate the effect of total electrochemical cell resistance (TECR) on electrochemical impedance (EI) measurements of reinforced concrete (RC) by electrochemical impedance spectroscopy (EIS) using a three-electrode system. A series of experimental study is performed to measure electrochemical behavior of a steel bar embedded in a concrete cube specimen, with a side length of 200 mm, in various experimental conditions. Main variables include concrete dry conditions, coupling resistance between sensing electrodes and concrete surface, and area of the counter electrode. It is demonstrated that EI values remains stable when the compliant voltage of a measuring device is sufficiently great compared to the potential drop caused by TECR of concrete specimens. It is confirmed that the effect of the coupling resistance of TECR is far more influential than other two factors (concrete dry conditions and area of the counter electrode). The results in this study can be used as a fundamental basis for development of a surface-mount sensor for corrosion monitoring of reinforced concrete structures exposed to wet-and-dry cycles under marine environment.