• Title/Summary/Keyword: Ground current

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Derivation of Synergistic Aerosol Model by Using the ECMWF/MACC and OPAC (ECMWF/MACC와 OPAC자료를 이용한 시너지 에어로솔 모델 산출)

  • Lee, Kwon-Ho;Lee, Kyu-Tae;Mun, Gwan-Ho;Kim, Jung-ho;Jung, Kyoung-Jin
    • Korean Journal of Remote Sensing
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    • v.34 no.6_1
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    • pp.857-868
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    • 2018
  • The microphysics and spatio-temporal distribution of atmospheric aerosols are responsible for estimating the optical properties at a given location. Its accurate estimation is essential to plan efficient simulation for radiative transfer. For this sake, synergetic use of reanalysis data with optics database was used as a potential tool to precisely derive the aerosol model on the basis of the major representative particulates exist within a model grid. In detail, mixing of aerosol types weighted by aerosol optical depth (AOD) components has been developed. This synergetic aerosol model (SAM) is spectrally extended up to $40{\mu}m$. For the major aerosol event cases, SAM showed that the mixed aerosol particles were totally different from the typical standard aerosol models provided by the radiative transfer model. The correlation among the derived aerosol optical properties along with ground-based observation data has also been compared. The current results will help to improve the radiative transfer model simulation under the real atmospheric environment.

The Need and the Direction to Improve the System of Measures for the Preservation of Buried Cultural Heritage (매장문화재 보존조치 제도의 개선 필요성과 방향)

  • Ryu, Ho-cheol
    • Korean Journal of Heritage: History & Science
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    • v.47 no.3
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    • pp.146-159
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    • 2014
  • After inspecting ground surface or excavating cultural heritage site, the government can take measures for the preservation of buried cultural heritage based on the related law. It means that the provisions complement the limitation of current cultural heritage management system by extending the scope of cultural heritage to be preserved. But we neither have set any matters about implementing the measures for preservation of the buried cultural heritage, nor manage the heritage and its surroundings after implementing the measures. Due to these insufficiency of the law, there arise several problems in the field. For example, the measures for preservation are not complete, or preserved cultural heritage is damaged due to inappropriate management. We have to resolve the problems in order to accomplish the original purpose of taking measures for preservation of the heritage. First, it is necessary to make sure of the legal status of preserved buried cultural heritage, to establish the standards to decide whether to preserve it or not. We need to have regulations by law or internal rule on the daily management, who should manage it, what and how the manager should manage. It is also important for local residents to take an active part in preserving and utilizing the cultural heritage as the owner. Through building up the foundation mentioned above, the meaning and value of preserved buried cultural heritage can be expanded widely.

A Study on the Original Form of the Chwihyanggyo Bridge and the Creation of the Hyangwonjeong in Gyeongbokgung Palace (경복궁(景福宮) 향원정(香遠亭)의 조성시기(造成時期)와 취향교(醉香橋)의 원형(原形))

  • Nam, Ho Hyun;Kim, Tae Min
    • Korean Journal of Heritage: History & Science
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    • v.51 no.4
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    • pp.192-207
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    • 2018
  • The Hyangwonjeong and Chwihyanggyo located in the back garden of Gyeongbokgung Palace have mainly been investigated by referring to historical records about the reign of King Gojong and various drawings thought to have been made in the late Joseon period. Because the current Chwihyanggyo was rebuilt temporarily after being burned to the ground during the Korean War, its form and the location of its reconstruction are not grounded on any accurate historical investigation. Although there are some photos of the Chwihyanggyo that were taken between the end of the Joseon period and the Japanese colonial era, there is no information about the photographer or when they were taken, and it is hard to see which photos show the original Chwihyanggyo Bridge with them. The Cultural Heritage Administration, which is currently promoting the restoration of the Chwihyanggyo, has recognized this problem and initiated research on the matter. In 2017, an excavation survey successfully identified the original location of the Chwihyanggyo, as well as that of Hyangwonji Gado (假島), and the shape of the first foundation stone in the pier. With these findings it was possible to infer the ways in which the Chwihyanggyo has changed over the years. Moreover, by measuring the AMS (Accelerator Mass Spectrometer) of the samples collected in the mounding layer of the Gado where the Hyangwonjeong is located, it was discovered that the Hyangwonjeong was constructed sometime after the Imjin waeran (Japanese Invasion of Korea in 1592), which means that the theory that 'the late Joseon Hyangwonjeong was not the former early Josenn Chwirojeong' is groundless. Judging by the materials found to date, we can reasonably assume that the Chwihyanggyo and Hyangwonjeong must have been built around the same time that Geoncheonggung Palace was founded in the late Joseon period.

A Survey on Usage of Korean Standard Records Management System (표준기록관리시스템의 활용현황 연구)

  • Lee, So-Yeon
    • The Korean Journal of Archival Studies
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    • no.43
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    • pp.71-102
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    • 2015
  • The present study aims at investigating the current usage patterns of Korean Standard Records Management System. The Korean Standard Records Management System has been designed and distributed by the National Archives Korea in order to support records management of public agencies. An email survey has been sent to 4 types of public agencies: central government agencies, provincial governments, provincial education offices as well as city and county offices. While all agencies are included in the survey for the first three types, only two provincial districts are selected for city and county offices, Out of 101 email questionnaires sent, 65 are returned(63.73%). The results show the usage patterns of 240 functionalities aligned to 9 main functions: accession from records creators, preservation, appraisal, accession to the national archives, reference management, access and tracking, retrieval and use, system management as well as freedom of information management by public institutions. Since its launch in 2007, the system has been distributed to 707 public agencies as of late 2014. The problem is that there has been no attempt to evaluate the functionalities and usabilities of the system. Only grievances from those agencies implemented the system have never been ceased. The present study is expected to offer the levelled ground for productive discussion between the national archives and the agencies.

Development of Environmentally Friendly Backfill Materials for Underground Power Cables Considering Thermal Resistivity (열 저항특성을 고려한 지중송전관로 친환경 되메움재 개발)

  • Kim, Daehong;Oh, Gidae
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.1
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    • pp.13-26
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    • 2011
  • Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need for cable backfill materials to be maintained at a low thermal resistivity during the service period. Temperatures greater than $50^{\circ}C$ to $60^{\circ}C$ may lead to breakdown of cable insulation and thermal runaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aimed at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. The results of Dong-rim river sand (relatively uniform) show that as water content level increases, thermal resistivity tends to decrease, whereas the thermal resistivity on dry condition is very high value($260^{\circ}C-cm/watt$). In addition, other materials(such as Jinsan granite screenings, A-2(sand and gravel mixture), E-1(rubble and granite screenings mixture) and SGFC(sand, gravel, fly-ash and cement mixture)) are well-graded materials with low thermal resistivity($100^{\circ}C-cm/watt$ when dry). Based on this research, 4 types of improved materials were suggested as the environmentally friendly backfill materials with low thermal resistivity.

Diagnosis of the growth status and actual condition of the remaining old trees in the village - Focused on Hyeongok-myeon in Gyeongju-si - (마을 내 잔존 노거수의 생육현황 및 실태진단 - 경주시 현곡면을 중심으로 -)

  • Kim, Young-Hun;Deng, Bei-Jia;Chen, Geng;You, Ju-Han
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.23 no.6
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    • pp.109-123
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    • 2020
  • The purpose of this study is to provide basic data for the establishment of future countermeasures by diagnosing the growth status and actual condition of undesignated old trees distributed in Hyeongok-myeon, Gyeongju, Gyeongsangbuk-do. The number of old trees surveyed was 2 weeks in Gajeong-ri, 2 weeks in Haguri, 3 weeks in Nae-Tae-ri, 1 week in Nawon-ri, 6 weeks in Oryu-ri, 3 weeks in Sangguri, and 2 weeks in Sohyeon-ri, The trees species composition was 6 trees Celtis sinensis Pers., 1 Diospyros lotus L. trees, 4 trees Salix chaenomeloides Kimura trees, 2 Styphnolobium japonicum L. trees, and 7 Zelkova serrata (Thunb.) Makino trees. Growth status is 7.1~22.0m in height, 14.6~25.1m in long axis, 10.2~19.2m in short axis, root diameter is 76.0~236.4cm, diamter at breast height is 67.0~220.0cm, soil acidity is pH4.9~7.0, soil The hardness was measured to be 4.0-27.0mm. The result grade of the scoring data of health information is represented by monitoring generally, monitoring critically, and absolute monitoring, and it was confirmed that out of the 20 trees population in Hyeongok-myeon, the general monitoring grade was 7 weeks, the major monitoring grade was 13 weeks, and there was no absolute monitoring grade. Accordingly, the number of old trees of the general surveillance level was maintained at the current level, and ecological surgical operations were introduced for the major surveillance level, but the case of village forests should be different, and sequential treatments were the old tree urgently needed. The level and bark of the target tree, the state of the crown, the root exposure, the presence of pests and pests, the vitality and the ground condition, the degree of pollution are normal, poor, or very poor, operation and protection management, soil improvement, removal of cover, and disinfection were urgently needed for the old trees with the surveyed data. In order to compensate for these matters, continuous monitoring and management measures for the old number should be sought.

Seismic Performance Evaluation of Dam Structures and Penstock Considering Fluid-Structure Interaction (유체-구조물 상호작용을 고려한 댐 구조체와 수압철관의 내진성능평가)

  • Heo, So-Hyeon;Nam, Gwang-Sik;Jeong, Yeong-Seok;Kwon, Minho
    • Land and Housing Review
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    • v.13 no.1
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    • pp.141-150
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    • 2022
  • Responding to the increasing demand for research on seismic resistance of structures triggered by a large-scale earthquake in Korea, the Ministry of the Interior and Safety revised the typical application of the existing seismic design standards with the national seismic performance target enhanced. Therefore, in this paper, the dam body of the aged Test-Bed and the penstock with fluid were modeled by the three-dimensional finite element method by introducing several variables. The current seismic design standard law confirmed the safety of the dam structure and penstock against seismic waves. As a result of the 3D finite element analysis, the stress change due to the water impact of the penstock was minimal, and it was confirmed that the effect of the hydraulic pressure was more significant than the water impact in the earthquake situation. When the hydrostatic pressure is in the form of SPH, it was analyzed that the motion of the fluid and the location of stress caused by the earthquake can be effectively represented, and it will be easier to analyze the weak part. As a result of the analysis, which considers penstock's corrosion, the degree of stress dispersion gets smaller because the penstock is embedded in the body. The stress result is minimal, less than 1% of the yield stress of the steel. In addition, although there is a possibility of micro-tensile cracks occurring in the inlet of the dam, it has not been shown to have a significant effect on the stress increa.

A Comparative Analysis of Keywords in Astronomical Journals and Concepts in Secondary School Astronomy Curriculum (최근 천문학 연구 키워드와 천체 분야 교육과정 내용 요소 비교 분석)

  • Shin, Hyeonjeong;Kwon, Woojin;Ga, Seok-Hyun
    • Journal of The Korean Association For Science Education
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    • v.42 no.2
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    • pp.289-309
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    • 2022
  • In recent years, astronomy has been snowballing: including Higgs particle discovery, black hole imaging, extraterrestrial exploration, and deep space observation. Students are also largely interested in astronomy. The purpose of this study is to discover what needs to be improved in the current astronomy curriculum in light of recent scientists' researches and discoveries. We collected keywords from all papers published from 2011 to 2020 in four selected journals-ApJ, ApJL, A&A, and MNRAS- by R package to examine research trends. The curriculum contents were extracted by synthesizing the in-service teachers' coding results in the 2015 revised curriculum document of six subjects (Science, Integrated Science, Earth Science I, Earth Science II, Physics II, Convergence Science). The research results are as follows: first, keywords that appear steadily in astronomy are 'galaxies: formation, galaxy: active, star: formation, accretion, method: numerical.' Second, astronomy curriculum includes all areas except the 'High Energy Astrophysical Phenomena' area within the common science curriculum learned by all students. Third, it is necessary to review the placement of content elements by subject and grade and to consider introducing new concepts based on astronomy research keywords. This is an exploratory study to compare curriculum and the field of scientific research that forms the basis of the subject. We expect to provide implications for a future revision of the astronomy curriculum as a primary ground investigation.

Commercial fishery assessment of Malaysian water offshore structure

  • Mohd, Mohd Hairil;Thiyahuddin, Mohd Izzat Mohd;Rahman, Mohd Asamudin A;Hong, Tan Chun;Siang, Hii Yii;Othman, Nor Adlina;Rahman, Azam Abdul;Rahman, Ahmad Rizal Abdul;Fitriadhy, Ahmad
    • Fisheries and Aquatic Sciences
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    • v.25 no.9
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    • pp.473-488
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    • 2022
  • To have a better understanding of the impact of the PETRONAS oil and gas platform on commercial fisheries activities, Universiti Malaysia Terengganu (UMT) examined two approaches which are data collection from satellite and data collection from fishermen and anglers. By profiling the anglers who utilize reefed oil and gas structures for fishing, it can determine if the design and location of the reef platforms will benefit or negatively impacts those anglers and fisherman. Furthermore, this assessment will be contributing to the knowledge regarding the value of offshore oil and gas platforms as fisheries resources. Collectively, the apparent fishing activity data included, combined with the findings in the reefing viability index will help to inform PETRONAS's future decommissioning decisions and may help determine if the design and proposed locations for future rigs-to-reefs candidates would benefit commercial fishing groups, further qualifying them as appropriate artificial reef candidates. The method applied in this study is approaching by using a data satellite known as Google's Global Fishing Watch technology, which is one of the applications to measure commercial fishing efforts around the globe. The apparent commercial fishing effort around the selected twelve PETRONAS platforms was analyzed from January 2012 to December 2018. Using the data collection from fishermen which is the total estimation of commercial fish value cost (in Malaysia ringgit, MYR [RM]) in Peninsular Malaysia Asset, Sabah Asset, and Sarawak Operation region. The data were extracted every month from 2016 to 2018 from the National Oceanic and Atmospheric Administration database. Most of the selected platforms that show a high frequency of vessels around the year are platform KP-A, platform BG-A and platform PL-B. The estimated values of commercial fishes varied between platforms, with ranged from RM 10,209.92 to RM 89,023.78. Thus, platforms with high commercial fish value are selected for reefing in-situ and will serve multi-purposes and benefit the locals as well as the country. The current study has successfully assessed the potential reefing area of the Malaysian offshore environment with greater representativeness and this paper focused on its potential as a new fishing ground.

The Safety Management Status and Policy Directions for Sports Facilities in Gangwon Province (강원도 체육시설 안전관리 실태와 정책방향)

  • Kim, Tae-Dong;Kim, Heung-Tae
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.4
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    • pp.265-288
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    • 2020
  • Public sports facilities, which have increased in number due to continued government attention and investment, are used by a large number of residents in the province. However, the safety management in some facilities is limited due to being carried out with reference to safety management standard manuals as a mere formality. The purpose of this study was to analyze the current safety management status of public sports facilities in Gangwon and to seek out a policy direction that can be used safely by provincial residents. To this end. the study made a comprehensive review of central government and Gangwon government policy trends in sports facility safety management in Gangwon along with actual cases, from which it made the following suggestions for policy directions. First, it proposed the designation and operation of specialized institutions using locally established development and municipal companeie,. universities and cooperatives. and the training and fostering of safety managers for sports facilities. Secod, it proposed the establishment of a foundation to promote a sport facility safety culture such as designation of and commendation for excellent facility safety management on the provincial level. holding case presentations on safety and responsiveness. sports safety experience plazas, sports safety classes, and cartoons for public relations. Third, it proposed setting the foundation for a safety management system that takes into account the greater quantity of leisure sports facilities compared to other cities and provinces. Fourth, it proposed the establishment of an institutional basis to establish support ordinance for sports facility safety management that meets the local conditions in Gangwon. Fifth, it proposed safety management measures for sports facilities at the central government level in parallel with a basic plan for sports facility safety management tailored to Gangwon that matches the conditions on the ground in the region.