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암호화 속도 향상을 위한 디지털 콘텐츠의 특징 영역 암호화
조상일(Sangil Cho),홍광진(Kwangjin Hong),정기철(Keechul Jung) 한국정보과학회 2005 한국정보과학회 학술발표논문집 Vol.32 No.2
디지털 영상 콘텐츠는 쉽고 빠르게 복제와 전송이 가능하기 때문에 다수의 사용자가 동일한 콘텐츠를 공유하는 것이 가능하다. 이러한 디지털 콘텐츠의 특징은 많은 디지털 영상 콘텐츠 제작자의 창작 의욕을 저하시키고 콘텐츠 산업 발달을 저해하는 원인이 되고 있다. 따라서 최근 디지털 콘텐츠의 보호를 위한 다양한 연구가 활발하게 이루어지고 있다. 그러나 기존의 가산 암호 방식은 암호의 비도면에서 영상 암호화에 사용된 암호키를 추정할 수 있다는 단점이 있으며 난수 정보가 해독될 우려가 있다. 또한 주사선내 신호 절환 방식은 원영상의 히스토그램 정보를 그대로 담고 있어 암호화된 영상의 히스토그램 정보로 원영상의 종류를 추정할 수 있는 단점이 있고 블록간의 상관 관계를 계산하여 해독할 수 있다는 단점이 있다. 본 논문에서는 디지털 영상 콘텐츠의 특정 영역을 추출하고 이 영역에 대한 암호화를 함으로써, 새로운 암호 알고리즘의 개발 없이 기존의 알고리즘을 이용하여 암호화 속도를 개선하고 안전성을 향상시킬 수 있다.
A Study of Fracture Behavior of Spent Fuel in Long-Term Dry Storage
Sangil Choi,Sangsoon Cho,Seunghwan Yu 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
To investigate the mechanical integrity of spent nuclear fuel, the failure behavior of the cladding tube was examined under accident conditions. According to the SNL report, the failure behavior of cladding can be broadly classified into two types. The first is failure due to bending load caused by falling. The second is failure due to pinch load caused by space grid. In this study, mechanical integrity was evaluated through the stress intensity factor applied to the crack in failure behavior due to bending load. Since the exact value of the impact load due to fall was unknown, the load was applied by increasing the value up to 200 G in 20 G increments. The size of the crack is an important input variable, and 300 um was given by referring to the EPRI report, and the elastic modulus, a material property that determines the stress field, was given 75.22 GPa by referring to the FRAPCON code. Since the relationship between the direction of stress and the direction of the crack is also a major variable, simulations were conducted for both cracks perpendicular to and parallel to the stress direction. It was confirmed that at a load of 200 G, when the crack was parallel to the stress direction, stress concentration did not occur and had a very low stress intensity factor 0.01 ???√?. When perpendicular to the direction of stress, the stress intensity factor showed a value of 1 ???√?. However, considering that the critical value of the stress intensity factor due to hydride is 5 ???√?, it can be seen that perpendicular result also ensures the mechanical integrity of the cladding.
A Study of Mechanical Degradation Behavior of Spent Fuel in Long-term Dry Storage
Sangil Choi,Sangsoon Cho,Seunghwan Yu 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1
Research on the safety of nuclear spent fuel has been heavily experimented and modelled from a mechanical perspective. The issues of corrosion, irradiation creep, hydride and hydrogen embrittlement have been addressed more than two decades since the early 2000s. Among these degradation behavior, hydrogen embrittlement and hydride reorientation have been the most important topics for establishing the integrity of nuclear spent fuel and have been studied in depth. In order to assess the safety of spent nuclear fuel, firstly, it is necessary to establish the safety criteria in all nuclear cycle, i.e., the failure criteria guidelines for nuclear fuel assemblies and nuclear fuel rods, and then examine the safety analysis. The contents of U.S.NRC Regulations, Title 10 General, Chapter 1 Code of Federal Regulation (CFR), Part 50, 71 and 72, describe the safety criteria for the safety assessment of nuclear fuel assemblies and nuclear fuel rods. In this study, technically important points in safety analysis on nuclear fuel are checked through the reference of those NRC regulation. As result, we confirmed that the safety assessment of nuclear fuel after 20 years of interim storage is now being tested by ORNL and PNNL. There are not quantitative criteria related to material safety. However qualitative criteria which is dependent on environmentally condition describe the safety analysis. There is some literature study about DBTT, yield stress, ultimate tensile strength, flexural rigidity data. In FRAPCON code Modelling of yield strength and creep had been established, but radial hydride or hydride reorientation has not considered.
Cho, Giphil,Jeong, Yong Dam,Kim, Sangil,Jung, Il Hyo The Youngnam Mathematical Society 2018 East Asian mathematical journal Vol.34 No.5
We consider an optimal control problem for an impulsive stage-structured model involving ordinary differential equations with impulsive values of initial conditions in the next year. The main goal is to maximize a profit of the catch of Pacific cod in the South Korea through optimal harvest strategy as a control of adult cod. We established necessary conditions for the optimal harvest control using idea of Pontryagin's maximum principle. The optimal harvest strategy is to numerically solve the equation by using an iterative method with the Runge-Kutta method. Finally, we compare a monthly average of fishing mortality of Pacific cod from 2013 to 2017 with monthly fishing mortality for result obtained optimal harvest strategy.
이상일(Sangil Lee),안강모(Kangmo Ahn),이광신(Kwangshin Lee),권헌교(Heongyo Kwon),조혜진(Hyejin Cho),김종희(Jonghee Kim) 한국산림휴양학회 2010 한국산림휴양학회지 Vol.14 No.2
최근 숲의 치유기능에 대해 임학과 의학 분야에서 큰 관심을 보이고 있다. 본 연구는 국립공원 치유 캠프가 아토피피부염 환자들의 증상완화에 미치는 영향을 평가하고자 수행되었다. 치유 캠프의 효과는 의사 진단에 의한 환자의 중증도와 환자 본인의 가려움 정도를 캠프 전·후 평가하여 검증하였다. 연구결과, 국립공원 치유캠프는 아토피피 부염 환자들의 증상 호전 및 심리적 안정에 효과적인 것으로 나타났다. The therapeutic effect of forest settings is an emerging issue in the field of forestry and medicine. The purpose of this study was to evaluate the therapeutic efficacy of the national park healing camp for patients with atopic dermatitis (AD). Using pre-test and post-test group design with objective and subjective SCORAD score, mean changes in patient with atopic dermatitis by completion of the healing camp was measured. The result of this study indicated that the national park healing camp showed that has potential as an improved health status and psychological relaxation for patients with AD.
Jewel CAD와 RP를 활용한 시계 케이스 디자인 간편화에 대한 연구
조선형(Cho, Sunhyung),여은구(Yeo, Eunku),임경제(Lim, Kungie),방동규(Bang, Dongkyu),신상일(sin, Sangil) 한국디지털디자인협의회 2007 디지털디자인학연구 Vol.7 No.1
21세기에 들어서면서 시장의 형태는 국제화, 개인화로 변화되고 진화되어 왔다. 소비자의 디자인 감각과 구매 욕구는 정보의 속도가 빨라짐에 따라 더욱 다양한 방향으로 발전되고 있음을 알 수 있다. 제품디자인의 영역이 한정된 디자이너의 아이디어에 멈춰있는 것이 아니라 소비자가 직접 선택할 수 있는 기술적, 환경적 상황이 되어가고 있다. 본 연구에서 그러한 마케팅전략의 기초단계로 시계 케이스를 6가지 형태로 분류하여 총200개의 디자인 데이터를 DB화 했다. DB의 데이터를 주얼캐드로 만들어 3차원 디자인 데이터에 소비자가 원하는 다양한 질감을 입혀서 랜더링한 것을 화면으로 바로 확인하고, 고속 원형제작시스템(RP)과 연계하여 소비자가 선택한 DB의 제품을 왁스의 형태로 출력할 수 있는 시스템을 구현하였다. In 21C, the form of the matket was changed to an internationalization and personalism. A design sense and desire of the consumer have been developed into various direction. The area of the good design does not stay in the idea of the designer to be restricted. Technical environment become which the consumer can make directly creative design. In this research to the basis stage of the marketing strategy, we classified a watch case as 6 styles. We made 200 design of watch as Data. We make the surface which the consumer wants at a design data on and show on the screen to rendering. We made the system to output as the form of the wax the goods which the consumer chooses a design of DB.