• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.77-80
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• 2006

고체 추진기관 둔감화는 고유 성능의 변화 없이 화재, 충격 등에 의한 우발적 사고시 반응의 정도를 최소화하는 기술로 정의된다. 열에 노출된 추진제가 점화되기 전에 연소관에 배기구가 형성되어, 추진기관 반응의 위험도를 낮추는 방법은 추진기관 둔감화의 핵심 기술 중 하나로, 이를 완화장치라 부른다. 본 논문은 완화장치와 관련된 최근의 연구 동향을 소개하였다.

• 한국재난정보학회 논문집
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• 제15권4호
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• pp.502-513
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• 2019

연구목적: 본 연구는 기업재난관리표준의 요구사항에 대한 재해경감활동계획 수립절차와 재해경감활동관리체계를 검토하고자 한다. 연구방법: 기업재난관리표준의 적용범위에 규정된 재난관리 단계별 각 활동을 포함한 요구사항을 파악하고 'A'기관의 운용사례를 검토하였으며 요구사항에 맞는 업무연속계획 대상을 검토하였다. 연구결과: 기업재난관리표준의 요구사항인 재난관리 단계별 내용과 절차를 명확히 정의하고, 4단계별 활동에 대한 업무연속성계획 수립이 필요한 것으로 검토되었다. 결론: 기업재난관리표준 요구사항에 대하여 재난관리활동 각 단계별 활동을 포함한 PDCA모델을 제시하였고, 재난의 예방 및 대비계획을 포함하는 광의의 재난관리 개념의 재해경감활동관리체계 모델을 제안하였다.

• Journal of Communications and Networks
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• 제10권2호
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• pp.127-136
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• 2008

For mobile wireless systems with full frequency reuse, co-channel interference near the cell coverage boundaries has a significant impact on the signal reception performance. This paper addresses an approach to efficiently mitigate the effect of downlink co-channel interference when multi-antenna terminals are used in cellular environments, by proposing a signal detection strategy combined with a system-level coordination for dynamic frequency reuse. We demonstrate the utilization of multi-antennas to perform spatial demultiplexing of both the desired signal and interfering signals from adjacent cells results in significant improvement of spectral efficiency compared to the maximal ratio combining (MRC) performance, especially when an appropriate frequency reuse based on the traffic loading condition is coordinated among cells. Both analytic expressions for the capacity and experimental results using the adaptive modulation and coding (AMC) are used to confirm the performance gain. The robustness of the proposed scheme against varying operational conditions such as the channel estimation error and shadowing effects are also verified by simulation results.

• 한국환경과학회지
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• 제25권10호
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• pp.1397-1405
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• 2016

Mussels are stubborn organism attached to solid substrate by byssus threads and caused operational problems in utility of power generating stations. Sole and combined usage of ultrasonic (28 kHz- and 42 kHz- frequencies) and hydrogen peroxide ($H_2O_2$) has studied for control of blue mussel larvae and adult stage in seawater condition. A theoretical wo rking model using disinfection (Chick and Watson type) approaches is presented based on helpful results of experiments. This study also demonstrate that the combined treatment (ultra-sonication with $H_2O_2$) is overall highly efficient than individual treatment would, but on the basis of exposure time, the ultra-sonication was the most efficient among them. Therefore the development of sole and combined technique might be effective practical mitigation strategy against mussel attachment for water handling facilities.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권6호
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• pp.8-18
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• 2015

Pollutants such as heavy metals and explosives originating from the military operational ranges can be migrated to adjacent surface water body or offsite soil, and can affect to local residents and aquatic ecosystem. Therefore, Korea Ministry of the National Defense has established various guidelines for environmental management including the installation of pollutant migration prevention facilities (PMPFs) and monitoring methodologies for heavy metals in the operational range soil and effluent and sediment of PMPFs. However, current guidelines neither address the explosive compounds such as 2, 4, 6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) nor suggest detailed environmental investigation protocol. This paper introduces the new “Environmental Management Manual for Military Firing Ranges”, which includes the environmental criteria for explosives as well as the detailed investigation protocol for the affected environmental media including soil, effluent and sediment of PMPFs.

• 항공우주시스템공학회지
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• 제16권3호
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• pp.52-62
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• 2022

특정범주 무인항공기 운용의 위험평가를 위해서 개발된 SORA 방법론에서는 지상 및 공중위험 등급을 결정하고 해당 위험도에 대한 특정보증 무결성 수준을 나타내는 SAIL이 할당되어 제안된 운용에 대한 운용 안전도 목표를 적절한 강건도 수준으로 입증해야 한다. 인명의 수송은 제외하는 특정범주 무인항공기 운용의 특성상 지상의 인명이 가장 먼저 고려되어야 하는 위험의 대상이며, 여기서 평가된 지상위험도는 공중위험도와 함께 SAIL의 할당에서도 중요한 역할을 한다. 위험도는 초기에 결정된 등급에 세 가지 종류의 완화수단이 적용되는 것으로 등급이 경감되어 최종 등급이 결정된다. 본 논문에서는 무인항공기의 특정범주 운용에 대한 위험평가 중에서 지상위험 등급의 결정과 완화수단의 적용을 통한 등급의 감소 및 최종 위험 등급에 따른 SAIL과 OSO에 미치는 영향에 대해서 분석하였다.

• 한국물환경학회지
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• 제22권1호
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• pp.110-115
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• 2006

Flooding situation of Sutak basin was simulated and simulation seemed to be consistent with the real flooding situation in terms of high water levels and timings of flooding. The flood simulation model was used to evaluate alternatives to mitigate flooding problems in Sutak basin. From the evaluation of flood mitigation plans, it was found that combined operation of Sutak and Inchang pumping stations through partial diversion of inflow of Sutak pumping station to Inchang pumping station was the most effective one among the suggested mitigation plans. About 500 meter diversion channel will be needed to send 30% of Sutak pumping station inflow to Inchang pumping station. This will reduce overload of Sutak pumping station and the storage capacity of Inchang pumping station will be more efficiently utilized.

• Smart Structures and Systems
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• 제23권3호
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• pp.295-306
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• 2019

Shanghai Tower is a 632-meter super high-rise building located in an area with wind and active earthquake. A sophisticated structural health monitoring (SHM) system consisting of more than 400 sensors has been built to carry out a long-term monitoring for its operational safety. In this paper, a reduced-order model including 31 elements was generated from a full model of this super tall building. An iterative regularized matrix method was proposed to tune the system parameters, making the dynamic characteristic of the reduced-order model be consistent with those in the full model. The updating reduced-order model can be regarded as a benchmark model for further analysis. A long-term monitoring for structural dynamic characteristics of Shanghai Tower under different construction stages was also investigated. The identified results, including natural frequency and damping ratio, were discussed. Based on the data collected from the SHM system, the dynamic characteristics of the whole structure was investigated. Compared with the result of the finite element model, a good agreement can be observed. The result provides a valuable reference for examining the evolution of future dynamic characteristics of this super tall building.

• 해양환경안전학회지
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• 제30권3호
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• pp.263-274
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• 2024

The digitization of ship environments has increased the risk of cyberattacks on ships. The smartization and automation of ships are also likely to result in cyber threats. The International Maritime Organization (IMO) has discussed the establishment of regulations at the autonomous level and has revised existing agreements by dividing autonomous ships into four stages, where stages 1 and 2 are for sailors who are boarding ships while stages 3 and 4 are for those not boarding ships. In this study, the level of a smart ship was classified into LEVELs (LVs) 1 to 3 based on the autonomous levels specified by the IMO. Furthermore, a risk assessment for smart ships at various LVs in different risk scenarios was conducted The cyber threats and vulnerabilities of smart ships were analyzed by dividing them into administrative, physical, and technical security; and mitigation measures for each security area were derived. A total of 22 cyber threats were identified for the cyber asset (target system). We inferred that the higher the level of a smart ship, the greater the hyper connectivity and the remote access to operational technology systems; consequently, the greater the attack surface. Therefore, it is necessary to apply mitigation measures using technical security controls in environments with high-level smart ships.

• Membrane and Water Treatment
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• 제8권5호
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• pp.395-409
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• 2017

Membrane bioreactor (MBR) is a compact and efficient wastewater treatment and reclamation technology; but, it is limited by membrane fouling. The control of membrane fouling significantly increases operational and maintenance costs. Bacteria and their byproducts - extracellular polymeric substances (EPS) - are major contributors to membrane fouling in MBRs. A recent attempt at fouling mitigation is the development of aerobic granular sludge membrane bioreactor (AGMBR) through the integration of a novel biotechnology - aerobic granulation - and MBR. This paper provides an overview on the development of AGMBR to mitigate membrane fouling caused by bacteria and EPS. In AGMBR, EPS are used up in granule formation; and, the rigid structure of granules provides a surface for bacteria to attach to rather than the membrane surface. Preliminary research on AGMBR using synthetic wastewater show remarkable membrane fouling reduction compared to conventional MBR, thus improved membrane filtration. Enhanced performance in AGMBR using actual municipal wastewater at pilot-scale has also been reported. Therefore, further research is needed to determine AGMBR optimal operational conditions to enhance granule stability in long-term operations and in full-scale applications.