• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.277-284
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• 2023

Since the radiological risk is different depending on the working environment, protection measures and policies must be developed through analysis of the field area environment. Evaluating the characteristics of the field area that uses radiation should be conducted through comparative analysis with other industries, not just the numerical value of the field area. In this study, evaluation factors were derived from exposure records by the department to compare radiation occupational exposure records by sector. And then, we developed a polygonal model for comparative analysis and applied them to eight work fields through ten evaluation factors. Based on the occupational exposure record in 2020, a polygonal model was applied to compare and evaluate the characteristics of the radiation work area. Through this, the usefulness of the polygonal model was confirmed, and protection policy measures for the industry were proposed.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.57-61
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• 2005

The objective of paper is to carry out a comparative Quantitative Risk Assessment (QRA) of two KOGAS tank designs using a fault tree methodology, a standard 'Full Containment' tank and a 'Membrane' tank. For the membrane tank, both the initial KOGAS design and 4 modified KOGAS designs have been assessed, giving six separate cases. In this paper, the frequencies of releases are quantified using a fault tree approach. For clarity in the analysis, and to ensure consistency, all cases have been quantified using the same fault tree. Logic within the fault tree is used to select each of the cases. Full quantification of risks is often difficult, owing to a lack of relevant failure data, but the aim of this study has been to be as quantitative as possible, with full transparency of failure information. The most significant general cause of external LNG leaks is predicted to be a seismic event, which has been quantified nominally. 4modified KOGAS desiens to Prevent damage of bottom membrane panels that was shown in preparatory estimation could quantitively confirm safety improvement. According to result, the predicted frequencies of an external LNG leak for the full containment and modified membrane tanks are very similar, failures due to dropped pumps are predicted to be significantly greater for the membrane tank with thickened plate than for the full containment tank.

• Convergence Security Journal
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• v.17 no.3
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• pp.73-81
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• 2017

In April 2009, in the wake of President Obama's Prague speech, the international community held four nuclear sec urity summits from 2010 to 2016 to promote nuclear security and prevent nuclear terrorism. The Nuclear Security S ummit has made significant progress in preventing terrorists from attempting to acquire nuclear weapons or fissile materials, but it still has limitations and problems. To solve this problem, the international community should resume the joint efforts for strengthening bilateral cooperation and multilateral nuclear security regime, and the participating countries should strive to protect their own nuclear materials and fulfill their commitments to secure nuclear facilitie s. Second, the United Nations(UN), the IAEA(International Atomic Energy Agency), International Criminal Police Or ganization(INTERPOL), the Global Initiative to Combat Nuclear Terrorism(GICNT), and the Global Partnership(G P) must continue their missions to promote nuclear security in accordance with the five action plans adopted at the Fourth Nuclear Security Summit. Third, the participating countries should begin discussions on the management and protection of military nuclear materials that could not be covered by the Nuclear Security Summit. Fourth, the intern ational community must strive to strengthen the implementation of the Convention on the Physical Protection of Nuc lear Material(CPPNM) Amendment and International Convention for the Suppression of Acts of Nuclear Terrori sm(ICSANT), prepare for cyber attacks against nuclear facilities, and prevent theft, illegal trading and sabotage invo lving nuclear materials.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.779-786
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• 2022

This study is designed to examine the effects of Dioscorea Quinqueloba extract as a natural radiation protection agent on the prostate and heart of male rats. Dioscorea Quinqueloba extract is well known to prevent the male-specific disease and heart disease. In this study, the Gamma-ray 10 Gy was irradiated in whole body of male rat to identify radioprotective effect by Dioscorea Quinqueloba extract. After irradiation, tissue change, SOD (Superoxide Dismutase) activity changes and hematological changes were observed. DQ+IR group showed higher lymphocyte, white blood cell, platelet levels than the IR group. In the NC and DQ groups, the number of prostate gland cells and the gap between cells were relatively narrow. But in the IR group, the cells died significantly and the gap widened. In the DQ+IR group, the gap between cells increased similarly to the IR group, but the number of dead cells was noticeably smaller. In the NC and DQ groups, the cardiovascular and myocardium are clearly separated, and cell nuclei are in good condition. But in the IR group, the cardiovascular and myocardium boundaries were disrupted, and the number of dead cell nuclei was high. In the DQ+IR group, although the boundaries were widened, but not disrupted and the number of dead cell nuclei was high. Therefore, Dioscorea Quinqueloba extract is judged to have radioprotective properties for the prostate and cardiovascular.

• International Commerce and Information Review
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• v.16 no.2
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• pp.221-249
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• 2014

This study analyzed the sufficient conditions for Korean firm's foreign subsidiaries in order to evolve into a center of excellence for knowledge creation and diffusion. In this respect, the purpose of this study is to develop a new framework based on literatures related to subsidiary knowledge creation and a center of excellence. Specifically, we created seven decisive factors for subsidiary knowledge creation: two general factors, two strategic important factors, and three excellent factors. Each factor can be a necessary condition or sufficient condition according to research purpose. For example, the decentralized organizational structure belonging to general factors become a sufficient factor for facilitating subsidiary's knowledge creation but it become a necessary condition for a center of excellence because all subsidiaries with decentralized organizational structure cannot be strategically important subsidiaries. By using seven decisive factors, this study examines the determinants' validity theoretically and practically.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.103-108
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• 2000

현재 국내에 설치되어 사용중인 위험물 저장 탱크는 총 152,370 개로 이중 1만 리터미만의 저장 용량을 가진 탱크가 약 50%를 차지하고 있으며, 화재나 폭발 시 진압의 어려움으로 인하여 막대한 손실을 초래할 우려가 있는 5만 리터 이상의 대형 탱크도 2만개 이상이 된다. 이러한 대형 탱크의 방호를 목적으로 설치된 기존의 포 소화시스템은 기로제로 공기를 이용한 기계 포 소화시스템으로써 설비 구성상 복잡하고 설치비용이 높아 경제적으로 불리하며 화재 진압에 적용된 포가 열적, 물리적 요인들로 인하여 파괴될 때 방출되는 것이 공기이므로 이는 화재를 성장시키는 원인이 되기도 하여 소화성능 면에서도 불리하다(중략)

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.125-128
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• 2015

본 논문에서는 지역 최빈값과 가중치를 이용하여 새로운 히스토그램 평활화 방법을 제안한다. 여러 개의 평균명도값을 사용하여 히스토그램을 분할하는 기존 방식과는 달리 지역 최빈값과 전체 평균명도값을 사용하여 히스토그램을 분할한다. 지역 최빈값 산출 과정에서 지역의 범위를 조정할 수 있어 융통성 있는 히스토그램 분할 처리가 가능하다. 또한 히스토그램 분할 영역을 가중치에 기반해 새로운 영역의 히스토그램으로 분할한다. 해당 방법을 통해 발생빈도가 높은 명도의 과도한 변화 없이 화질개선 면에서 기존 히스토그램 평활화보다 좋은 효과를 얻을 수 있다. 다양한 크기와 히스토그램 분포를 가지는 영상을 대상으로 실험한 결과, 기존 히스토그램 평활화보다 광범위하게 사용될 수 있음을 확인하였고 특히 한쪽으로 치우쳐진 영상에 있어 더욱 효과적임을 알 수 있었다.

• Fire Science and Engineering
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• v.19 no.2 s.58
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• pp.37-44
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• 2005

We have conducted a numerical simulation under three-dimensional unsteady conditions in order to analyze the characteristics of flow and the distribution of $CO_2$ agent concentration according to the number of $CO_2$ agent nozzle. The engine room of a ship was selected as a protection space, and flow fields and $CO_2$ concentration fields were measured. In case of increasing the number of $CO_2$ nozzle from 2 nozzles to 4 nozzles, the distribution of CO2 concentration showed low, and in case of increasing the number of $CO_2$ nozzle to above 6 nozzles, the recirculating flow affected to all region was generated. In case of increasing the number of $CO_2$ agent nozzle to above 4 nozzles, the iso-concentration line below 0.36 expanded or contracted slightly. Therefor, the proper number and the arrangement of $CO_2$ agent nozzle are considered when $CO_2$ fire fighting system is designed.

• KOMUNHWA
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• no.60
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• pp.65-99
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• 2002

The main purpose of this article is mainly by analysing the military function and role of sword in army and combat field during Chosen dynasty. Firstly, this study is a pre-survey for the overall research on the troops with military sword. The Chosun army

• Journal of dental hygiene science
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• v.5 no.2
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• pp.63-70
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• 2005

The relation among the variables of dental hygienists' both personal protection and infection prevention education was investigated in order to identify the necessity of realization of personal protection and utilize in the development of educational programs. The study tools included structured questionnaire and in-home interview. Data analysis included frequency and t-test, and the relations among the variables were as below: (1) Dental hygienist's maskwearing was most well observed in Kyonggi-do (90.0%) by locations, and in the dental hospitals (84.8%) by working places, which was statistically significant. (2) Glove-wearing was most well observed in the university and the higher graduates population (59.1%) by academic background, and in the dental hospital (73.9%) by working place, which was statistically significant. (3) Protection glasses-wearing was most well observed in Guns, Ups, and Myons (82.4%) by locations, which was statistically significant. (4) Uniforms were hand-laundered at home in the 40.9% of the university and the higher graduates, which was statistically significant. (5) About infection management, 67.0% of 2-year college graduates and 71.7% of the respondents from dental hospitals had been educated during their college days, which was statistically significant. (6) About the necessity of infection education, 77.3% of the university graduates responded it is very necessary, which was statistically significant.