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2차원 소형 원심압축기 내의 정압 특성에 관한 실험적 연구
홍동민(Dong-Min Hong),정진택(Jin Taek Chung),최항철(Hang-Cheol Choi),신유환(You-Hwan Shin),김광호(Kwang-Ho Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
This study describes the performance and flow characteristics of a 2-D centrifugal compressor with vaneless diffuser. 2-D impeller has several distinctive features different from 3-D conventional impeller. Representatively, 2-D impeller has no inducer and twist of blade. Since it has constant blade height, the flow area is approximately constant, thus there is no diffusion in the impeller passage. As a result, unexpected pressure loss occurs at impeller inlet region and a regional strong jet flow appears in impeller discharge flow. Total pressure ratio was 1.15 at mass flow rate of 0.021㎏/sec and rotational speed of 45000rpm. The test facility was directly driven by an high speed electric motor without gear box and the test was conducted at 35000, 40000 and 45000rpm, respectively.
경항공모함 이·착함 성능평가 및 안전임무 수행범주 일관 해석 연구
홍사영(Sa Young Hong),박동민(Dong-Min Park),정재환(Jae Hwan Jung),서민국(Min-Guk Seo),조석규(Seok-Kyu Cho) 대한조선학회 2024 大韓造船學會 論文集 Vol.61 No.2
The Safe Operating Envelope (SOE) combined with Short-Take-Off and Vertical Landing (STOVL) performance is an essential consideration of a light aircraft carrier for design of hull shape with excellent seakeeping performance in terms of naval air operations as well as traditional naval ship missions such as Transit and Patrol (TAP), and Replenishment at Sea (RAS) and so on. A variety of procedures are systematically combined to determine SOE considering rather complicated missions associated with operation of aircraft onboard. The evaluation of take-off and landing safety missions onboard should consider wind effect on deck and severer seakeeping indices and standards compared with conventional naval ships. In order to support take-off and landing missions, various support activities of the crews are required. So, additional evaluation is needed for indicators such as MSI(Motion sickness Index) and MII(Motion Induced Interruptions), which are quantitative indicators of work ability that appear as a result of motion response. In this study, a standard procedure is developed including the seaworthiness performance indicators, standards, and evaluation procedures that should be considered during design of STOVL aircraft carrier. Analysis results are discussed in terns of air-wake on deck as well as seakeeping indices associated with design parameter changes in view of conceptual design of a light aircraft carrier.
네트워크 정보보호시스템 우회 공격에 대한 대응훈련 시나리오
홍정수,양동민,이봉환,Hong, Jeong Soo,Yang, Dong Min,Lee, Bong Hwan 한국정보통신학회 2018 한국정보통신학회논문지 Vol.22 No.5
현재 네트워크 정보보호를 위하여 다양한 보안 시스템들이 개발되어 활용되고 있다. 보안 솔루션을 도입하는 것만으로 보안상의 위험을 상당수 방지할 수 있지만, 보안 솔루션은 그 목적과 기능에 따라 적절한 형태로 사용되어야 충분한 가치가 발휘될 수 있다. 정보보호시스템에 많이 사용되는 보안 솔루션으로는 방화벽, IDS, IPS 등이 있다. 그러나 다양한 정보보호시스템을 도입하고 있더라도 이를 우회하여 공격하는 기법은 항상 존재한다. 본 논문에서는 정보보호시스템에서 우회공격 기법에 대한 대응 방안과 우회 공격 기법을 훈련에 적용할 수 있는 효과적인 훈련 시나리오를 제안한다. 제안한 대응 훈련 시나리오의 유효성을 검증하기 위해 GNS3 네트워크 시뮬레이터를 사용하였으며, VirtualBox를 이용하여 가상 운영체제를 구축하였다. 제안하는 네트워크 정보보호시스템을 우회하는 공격에 대한 대응훈련 시나리오는 실제 공격에 대응하는데 매우 효과적으로 활용될 수 있다. Nowadays, various security systems are developed and used for protecting information on the network. Although security solutions can prevent some of the security risks, they provide high performance only if used appropriately in accordance with their purposes and functionality. Security solutions commonly used in information protection systems include firewalls, IDS, and IPS. However, despite various information protection systems are introduced, there are always techniques that can threaten the security systems through bypassing them. The purpose of this paper is to develop effective training techniques for responding to the bypass attack techniques in the information security systems and to develop effective techniques that can be applied to the training. In order to implement the test bed we have used GNS3 network simulator, and deployed it on top of virtual operating system using VirtualBox. The proposed correspondence training scenario against bypassing information protection system attacks could be very effectively used to counteract the real attacks.