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네트워크 통신에서 패킷의 암호화 알고리즘의 키 해킹시 데이터 보안을 위한 조립알고리즘 제안
장승철(Jang, Seung-Chul),전문석(Jeon, Mun-Seok) 한국산학기술학회 2010 한국산학기술학회 학술대회 Vol.- No.-
오늘날 네트워크 통신은 다양한 해킹방법들로부터 데이터를 보호하기 위하여 다양한 암호화 알고리즘을 사용하여 통신하고 있다. 이렇게 사용되는 암호화 알고리즘에서 키가 누출되어 해킹되었을 경우 데이터에 대한 정보누출 및 수정, 삭제 등의 데이터 가공을 당하게 된다. 본 논문에서는 이러한 문제를 보완하기 위하여 본래의 데이터를 섞고, 재조립하는 조립알고리즘을 제안한다.
국내 연구용원자로 전출력 내부사건 1단계 확률론적안전성평가
이윤환,장승철,Lee, Yoon-Hwan,Jang, Seung-Cheol 한국안전학회 2021 한국안전학회지 Vol.36 No.3
This report documents the results of an at-power internal events Level 1 Probabilistic Safety Assessment (PSA) for a Korea research reactor (KRR). The aim of the study is to determine the accident sequences, construct an internal level 1 PSA model, and estimate the core damage frequency (CDF). The accident quantification is performed using the AIMS-PSA software version 1.2c along with a fault tree reliability evaluation expert (FTREX) quantification engine. The KRR PSA model is quantified using a cut-off value of 1.0E-15/yr to eliminate the non-effective minimal cut sets (MCSs). The final result indicates a point estimate of 4.55E-06/yr for the overall CDF attributable to internal initiating events in the core damage state for the KRR. Loss of Electric Power (LOEP) is the predominant contributor to the total CDF via a single initiating event (3.68E-6/yr), providing 80.9% of the CDF. The second largest contributor is the beam tube loss of coolant accident (LOCA), which accounts for 9.9% (4.49E-07/yr) of the CDF.
인공하수 조성 성분에 따른 SBR 처리 공정의 효율에 관한 연구
이장훈,장승철,권혁구,김동욱,Lee Jang-Hoon,Jang Seung-Cheol,Kwon Hyuk-Ku,Kim Dong Wook 한국환경보건학회 2005 한국환경보건학회지 Vol.31 No.2
The removals of organic matter, nitrogen and phosphate in wastewater were investigated with Sequencing Batch Reactor (SBR). Glucose and sodium acetate were Used for organic carbon source so as to know nutrient removal efficiency in proportion to MLSS concentration. In the case of glucose, the COD removal rate was $74\%,\;41\%\;and\;66\%$ in MLSS 5000, 3000 and 1000, respectively. On equal terms, the BOD was $57\%,\;21\%\;and\;38\%$, the T-N was $24\%,\;13\%\;and\;44\%$, and the T-P was $12\%,\;21\%\;and\;33\%$. As a result, the removal rate of organic materials showed the finest remove when MLSS was 5000, but the nutrient removal rate appeared as was best when MLSS was 1000. In the case of sodium acetate, the COD removal rate was $83\%,\;81\%\;and\;86\%$ in MLSS 5000, 3000 and 1000, respectively. On equal terms, the BOD was appeared by $76\%,\;82\%\;and\;92\%$, the T-N $57\%,\;42\%\;and\;78\%$, and the T-P $48\%,\;52\%\;and\;38\%$. As a result, organic and T-N removal rates were best when MLSS was 1000. But, the T-P removal rates were best when MLSS was 3000. Glucose was shown fast removal in reaction beginning, but screened by more efficient thing though sodium acetate removes organic matter, nitrogen and phosphate. Form of floc was ideal in all reactors regardless of carbon source and MLSS concentration. And its diameter was about $200\~500{\mu}m$.
리스크정보 최적화를 통한 국내 연구용원자로의 안전성 향상
이윤환,장승철,Lee, Yoon-Hwan,Jang, Seung-Cheol 한국안전학회 2022 한국안전학회지 Vol.37 No.2
This paper describes an attempt to improve and optimize the operational safety level of a domestic research reactor by conducting a probabilistic safety assessment (PSA) under full-power operating conditions. The PSA was undertaken to assess the level of safety at an operating research reactor in Korea, to evaluate whether it is probabilistically safe and reliable to operate, and to obtain insights regarding the requisite procedural and design improvements for achieving safer operation. The technical objectives were to use the PSA to identify the accident sequences leading to core damage, and to conduct sensitivity analyses based thereon to derive insights regarding potential design and procedural improvements. Based on the dominant accident sequences identified by the PSA, eight types of sensitivity analysis were performed, and relevant insights for achieving safer operation were derived. When these insights were applied to the reactor design and operating procedure, the risk was found to be reduced by approximately ten times, and the safety was significantly improved. The results demonstrate that the PSA methodology is very effective for improving reactor safety in the full-power operating phase. In particular, it is a highly suitable approach for identifying the deficiencies of a reactor operating at full power, and for improving the reactor safety by overcoming those deficiencies.
국내 원자력발전소의 주제어실 화재피난 리스크 평가를 위한 화재 시뮬레이션
강대일 ( Dae Il Kang ),김길유 ( Kilyoo Kim ),장승철 ( Seung Cheol Jang ),유성연 ( Seong Yeon Yoo ) 한국안전학회(구 한국산업안전학회) 2014 한국안전학회지 Vol.29 No.4
In this paper, to systematically assess the abandonment risk of main control room (MCR) fire, fire simulations with FireDynamics Simulator were performed and abandonment probabilities were estimated for the MCR bench-board fire of domestic referencenuclear power plant. The fire simulation scenarios performed in this study included propagating and non-propagating fires of the MCRbench-board, and the availability and unavailability of heating, ventilation, and air conditioning system (HVACS). The following resultswere obtained. First, temperature was the major abandonment impact factor for the MCR bench-board fire if the HVACS was availableand optical density was that if the HVACS was unavailable. Second, the fire scenario contributing the MCR bench-board fireabandonment risk was identified to be only the propagating fire. Third, it was confirmed that the abandonment probability of the MCRbench-board fire for domestic reference nuclear power plant could be reduced by using the fire modeling.