• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.5
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• pp.437-446
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• 2021

As flying vehicle's speed is getting faster, the magnitude of aerodynamic heating is getting bigger. High-speed vehicle's exterior skin is heated to hundreds of degrees, and electrical equipments inside the vehicle are heated, simultaneously. Since allowable temperature of electrical equipments is low, they are vulnerable to effect of aerodynamic heating. These days, lots of techniques are applied to estimate temperature of electrical equipments in flight condition, and to make them thermally safe from heating during flight. In this paper, new model building technique for thermal safety analysis is introduced. To understand internal thermal transient characteristic of electrical equipment, simple heating experiment was held. From the result of experiment, we used our new building technique to build thermal analysis model which reflects thermal transient characteristic of original equipment. This model can provide internal temperature differences of electrical equipment and temperature change of specific unit which is thermally most vulnerable part in the equipment. So, engineers are provided much more detailed thermal analysis data for thermal safety of electrical equipment through this technique.

• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.402-407
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• 2019

In this study, we investigated the habitat characteristics of a reservoir in Gyeongju City, Gyeongbuk, in which a large group of Mauremys reevesii (endangered species Class II and natural monument No. 453 in Korea) was discovered. We examined the biotic and abiotic factors that directly and indirectly threaten the survival of M. reevesii within the habitat. The reservoir where M. reevesii was discovered was built for agriculture and surrounded by submerged trees, dam, forests, reeds, and farmland (paddy field). All of the M. reevesii were found only in the submerged trees on the north side of the reservoir. We found 28 M. reevesii (8 juveniles) and 21 M. reevesii (16 juveniles) from field surveys on May 10th and August 9th, 2018, respectively. A number of red-eared sliders (Trachemys scripta elegans) and American bullfrogs (Rana catesbeiana), which threaten the survival of M. reevesii, were also found in and around the reservoir. Moreover, there were signs of excavation of cultural asset, chemical fertilizer, and household garbage, all of which are considered to be major threats to the survival of M. reevesii, all over the reservoir. Newborn turtles in this year were not observed. However, we estimated that natural breeding had sufficiently occurred since we observed many young turtles in the reservoir. Furthermore, the presence of young T. s. elegans individuals can be a persistent problem for M. reevesii as they are competing species. In conclusion, in-situ conservation method should be considered for protecting the endangered turtle and their habitat.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.243-251
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• 2007

Purpose : This study was conducted to assess the surgical outcomes of limbal lensectomy with or without anterior vitrectomy for the management of lens subluxation. Materials and Methods : The medical records of 20 consecutive patients (33 eyes) with lens subluxation who had undergone limbal lensectomy with or without anterior vitrectomy from February 1999 to January 2004 were retrospectively reviewed. Results : All the patients, except one high axial myopic patient, were implanted with scleral sutured posterior chamber intraocular lens. We evaluated the preoperative, postoperative visual acuity and postoperative complications and compared the results in group I (limbal lensectomy with anterior vitrectomy, 27 eyes) to those in group II (limbal lensectomy without anterior vitrectomy, 6 eyes). The preoperative best-corrected visual acuity was 0.21 and postoperative best-corrected visual acuity was improved by 2 lines or more in all 27 eyes in group I, and in 5 eyes in group II (p>0.05). The most frequent postoperative complication was intraocular lens dislocation in four eyes (14.8%) in group I alone. No retinal detachment occurred in either group, even in patients with high myopia. Conclusion : Limbal lensectomy without anterior vitrectomy improved visual acuity similarly to limbal lensectomy with anterior vitrectomy without significant increase of postoperative complications. This results of this study suggest that anterior vitrectomy is not necessarily required for the management of lens subluxation.

• Journal of the Korean Geographical Society
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• v.51 no.2
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• pp.269-281
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• 2016

This article problematizes and interrogates the idea of 'community' which is increasingly important in Korean urban policy-making. For the purpose, this article scrutinizes, and compares, how ordinary citizen participants and civil society activist organizations in a 'community garden' program of Seoul make sense of, utilize, and practice the policy concept. The neo-Faucauldian perspective of 'governmentality' is employed to understand the association between the community-focused policy program and neoliberalism, but Barnett's( 2005) call for 'bottom-up governmentality' is taken seriously in order to avoid any deterministic interpretation. On the basis of this eclectic perspective on governmentality, this article presents empirical findings that may suggest a contestation over community between ordinary citizens and civil society activists. More specifically, ordinary citizen participants prioritize place-based, on-the-ground community experiences that are built on common cultivation practices, whereas civil society activists tend to consider community garden as a teleological governmental technology generative of particular citizen subjects. Civic community garden advocacy as such aims to address social, economic, and spatial problems that neoliberalsim has produced, but it also appears to be in a close association with neoliberal urban policy. Thus, the community activism's meaningfulness lies in its active intervention to neoliberal urban policy, but a gap between ordinary practical achievements and civic activism can be a potential danger to urban community policy. On the basis of this discussion, this article asks more detailed investigations about the taken-for-granted positivity of urban community (re)vitalization programs, and also examinations on whether and how such projects generates emergent tensions between ordinary achievements and policy prescriptions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2206-2212
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• 2017

When it comes to naval surface warfare, the probability of detection is an important factor in survivability and the Radar Cross Section(RCS) is a major parameter. In this paper, the RCS reduction technology of the Radar Absorbing Material(RAM) method is carried out for the general frequency range for naval warfare. We set the analysis model with the simplified ship model and the wide band metamaterial which is high-tech radar absorbing materials is selected for the RAM method. The modeling of the wide band metamaterial composed of an MIK surface which has the wide band resonant properties and flexible substance and the electromagnetic absorptions and reflections of the wide band metamaterial has been simulated to explore the performance. Also, the wide band metamaterial is compared with the paint absorber to analyze RCS reduction in terms of RCS values.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.4
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• pp.633-646
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• 2023

The increases in UAVs(Unman Aerial Vehicle) such as drone result in safety issues and the threat of illegal drone as well. Recognizing the need for Drone forensics, domestic and foreign organizations and agencies are trying to establish drone forensic guidelines. The definition of Drone forensic artifacts and examination of forensic tools must be provided, in order to establish a practical drone forensic framework on security sites and also the concept of drone live forensic which provides meaningful data that can be extracted in a live state. In this study, the drone forensic methodology covering various types of drones is explained, and the practical forensic methodology with live forensic PoC(Proof Of Concept) tools; LiPFo(Live-PX4-Forenensic) is proposed.

• Strategy21
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• s.39
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• pp.242-250
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• 2016

본 논문은 왜 인도해군이 인도양을 벗어나 태평양 해역으로 진출하려는지에 대한 이유를 설명한다. 인도는 거대한 섬 국가이자, 해양국가이다. 이에 인도해군(Indian Navy: IN)은 인도양에서의 해양안보(maritime security) 활동을 주도하고 있으며, 이는 이 해양에서 발생되고 있는 다양한 비군사적 위협에 대한 기여로 나타나고 있다. 예를 들면 아덴만 해적퇴치작전 등이다. 인도는 지리적으로 중국 등의 대륙국가와 국경을 접하고 있으나, 태평양 연안국가들과 긴밀한 양자간 관계를 유지하고 있으며, 아울러 다양한 다자간 협력체에 적극적으로 참가하고 있다. 후자의 경우 EAS, ARF, ASEAN 등의 협력체이다. 또한 인도는 경제, 사회문화적으로 태평양 연안국가들과 동질성을 갖고 있다. 그 동안 인도해군은 태평양에 대한 많은 기여와 관심을 갖고 있었으며, 이는 서태평양해군심포지움(WPNS) 업저버 국가 등의 다양한 활동 확대에서 발견되고 있다. 인도는 동방정책(India's Look East Policy)를 외교정책으로 채택하고 있으며, 이는 태평양에서의 해양안보에 대한 기여와 참여를 의미한다. 이는 최근까지 왜 인도해군이 중국, 아세안, 한국, 일본 및 호주 등과 긴밀한 해양협력 관계를 유지하고 있는지에 대한 주된 이유를 설명한다. 이러한 인도해군의 기여는 태평양 해양에서의 해양 평화와 번영에 기여할 것으로 전망된다.

• Journal of the KSME
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• v.23 no.5
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• pp.326-334
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• 1983

1980년대에서는 생산성이 세계 제조업자들에게 특히 중요하게 된다. 이 기간 중에, 보호관세가 낮아져서 외국사람의 접근이 증가하게 되고, 국내 및 국외시장에서 경쟁 역시 증가될 것이다. 동 시에 전세계적인 산업자동화의 물결이, 급속히 증가하고 있는 컴퓨터와 산업용 로봇들을 근거로 제조업에 거세게 일 것이며, 이 기술변환의 지표로서, CAD/CAM에 관한 약 1,000개의 논문 및 서적과 기사가 매년 출판 발표되고 있다. 이러한 변화의 물결 중에서, 가장 급속히 진보하고 있는 2개의 첨단기술은, 컴퓨터응용설계를 위한 그래픽시스템의 사용이며, 생산기계류와 수치로 제어 되는 기계공구 사용과 더불어 부품과 공구취급을 위한 산업용 로봇의 사용이다. CAD/CAM이, 기업이나 산업국가에게 위협을 줄런지 또는 행운을 가져다 줄런지 결정하는 CAD/CAM 그 자 체가 아니라, CAD/CAM에 대한 기업이나 산업국가의 반응 및 그 활용에 있겠다.

• Review of KIISC
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• v.30 no.2
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• pp.59-63
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• 2020

국내 원자력발전소는 1978년 웨스팅하우스 노형의 고리1호기부터 2019년 APR-1400 노형의 신고리3호기 준공까지 많은 기술의 발전을 이룩하였다. 과거와 비교하여 현재의 원자력발전소는 단순히 발전용량만 증가한 것이 아니라, 안전에 대한 요구가 반영되어 발전하였다. 첫째, 미국 TMI 사고, 우크라이나 체르노빌 사고, 일본 후쿠시마 사고를 겪으며 자연재해, 인적실수 등에 관한 강화된 대책이 적용되었다. 둘째 미국 Browns Ferry 원전 정지, Hatch 원전 정지, 이란 핵시설 스턱스넷 공격 등을 겪으며, 사이버위협에 대응하기 위한 사이버보안 규제요건이 원자력발전소에 적용되었다. 그러나 사이버보안 규제요건과 원자력발전소 설계요건이 상충하는 부분이 일부 존재한다. 본 논문에서는 원자력발전소 사이버보안 규제요건과 상충하는 설계요건(Code&Standard)을 분석하여, 사이버 보안관점에서 요구되는 보안 조치사항을 도출하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.315-320
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• 1996

원자력 발전소에서의 중대사고시, 고온의 노심 용융물이 원자로 공동으로 떨어지면 노심용융물과 콘크리트간의 반응(MCCI)에 의한 여러가지 현상으로 인해 격납용기의 건전성을 위협할 수 있다. 본 연구에서는 노심 용융물의 모사체로 고온의 Thermite 20kg을 영광 원자력 발전소 3, 4호기에 사용된 콘크리트 시편에 부어 중대사고시 MCCI 현상을 모사하였다. 실험에서는 국내 콘크리트에서의 침식율, 가스 및 입자 발생률을 측정하였다. 실험에서 측정된 용융물의 최고 온도는 약 2230 $^{\circ}C$이고, 콘크리트 시편으로의 최대 하부 열유속은 초기에 약 1.1~1.3 MW/$m^2$로 나타났으며, 전체적인 콘크리트의 침식 깊이는 약 15mm 그리고 초기의 최대 침식율은 129 cm/hr로 나타났다. 향후에 이 실험 결과를 MELCOR 코드의 MCCI 해석 모듈인 CORCON-MOD3의 해석 결과와 비교할 예정이다.