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석병진(Byoungjin Seok),김역(Yeog Kim),이창훈(Changhoon Lee) 한국디지털콘텐츠학회 2017 한국디지털콘텐츠학회논문지 Vol.18 No.5
Because cyber attacks on industrial control systems can lead to massive financial loss or loss of lives, the standardization and the research on cyber security of industrial control systems are actively under way. As a related system, the industrial control system of social infrastructures must be equipped with the verified cryptographic module according to the e-government law and appropriate security control should be implemented in accordance with the security requirements of the industrial control system. However, the industrial control system consisting of the operation layer, the control layer, and the field device layer may cause a problem in performing the main function in each layer due to the security control implementation. In this paper, we propose things to check when performing security control in accordance with the security control requirements for each layer of the industrial control system and proper application.
Enhancing the Strength of Reticulated Foams by Infiltration Under Vacuum
Byoungjin So,Seok-Min Hong,Yung Zun Cho,Jae Soo Ryu 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
Reticulated foams have a continuous skeleton network consisting of aluminosilicates and are used for capturing gaseous cesium released from spent nuclear fuel at high temperature. It has high stability to high temperature and good capturing performance. Homogeneous cell distribution and modified surface structures are indispensable conditions for stable operation and handling. In particular, triangularly shaped holes inside the struts were generated during the pyrolysis of polyurethane sponge as a sacricial template, which lead to limite the strength of the reticulated foam as well as cracks. However, several attempts have been focused on the increasing the strut thickness. Here, we have prepared ceramic foams by the polyurethane sponge replication method with roller squeezing. Ceramic slurry including additives was determined with consideration of its viscous behavior. After pre-sintering, infiltration under vacuum was conducted. Metakaolin slurry was filled partially into the triangular void. As a result, the compression strength was improved by structure modification without composition change.
Toughening Kaolin-Based Ceramic Foams by Recoating
Byoungjin So,Seok-Min Hong,Yung Zun Cho,Jae Soo Ryu 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
One of released radioactive gases from a spent fuel is cesium (137Cs) as semi-volatile fission products and reticulated ceramic foam could be used for capturing the gaseous cesium. It has threedimensional open-pore structures and consumes cesium above 600°C to form cesium species including Cs-nepheline (CsAlSiO4) and pollucite (CsAlSi2O6) phases. Kaolinite-based foam filter is a favorable ceramic filter because they exhibit superior capture characteristics compared to other aluminosilicate minerals and other shape filters. However, for usage in special conditions, structural limitations such broken struts must be improved. Here, recoating by using centrifugation, followed by a pre-sintering cycle was conducted for covering the cracks and voids, resulting from the burnout of the polyurethane sponge as a sacricial template. The slurry including additives was chosen by considering viscous behavior of slurries for the centrifugation. The microstructure and strength was improved by the recoating.
Effect of Vertical Shaking on the Reduction of Uranium (IV, VI) Oxides for Damaged Spent Fuel
Byoungjin So,Ju Ho Lee,Sun Seok Hong,Seung Chul Oh,Jae Won Lee,Yung Zun Cho 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1
The stabilization technology for the damaged spent fuel is being developed to process the damaged fuel into sound pellet suitable for dry re-fabrication. It requires several treatments including oxidative decladding followed by reduction treatment for oxidized powder closely related to the quality of oxidized powders for pellet fabrication. For the development of operating condition for the reduction treatment, in this study, we evaluated the effect of air-cylinder based vertical shaking previously applied to oxidative decladding on powder reduction. For U3O8 of 50-100 g, the reduction test were applied with and without vertical shaking at 700°C under reduction atmosphere (Ar + 4%H2) and the concentration of hydrogen in effluent was measured to evaluate the reduction reaction. It was found that the vertical shaking system has allowed the reaction time of 50 g and 100 g U3O8 reduced by 33% compared to the test in static mode. Based on XRD analysis, the better crystallinity of the products was also achieved.
Practical operations for intermittent dual-layer slot coating processes
Jin Seok Park,Sanghun Jee,Byoungjin Chun,정현욱 한국유변학회 2022 Korea-Australia rheology journal Vol.34 No.3
Transient behaviors of dual-layered patches for Newtonian liquids were numerically investigated in dual-layer slot coating processes for the first time using step-changed inlet flows. To further tune the leading and trailing edges in a patch cycle, startup and end lag times between the top and bottom layers were proposed, considering the fl ow state of a bottom-layer liquid in a coating bead region. Carefully chosen lag times significantly reduced the defects in the leading and trailing edges of a dual-layered patch. It was also found that a greater coating layer viscosity results in a greater amount of residue left on the die lips, which affects the next patch cycle.
Rekeying Approach against Side Channel Attacks
( Tran Song Dat Phuc ),( Byoungjin Seok ),( Changhoon Lee ) 한국정보처리학회 2017 한국정보처리학회 학술대회논문집 Vol.24 No.1
Side-channel attacks and in particular differential power analysis (DPA) attacks pose a serious threat to cryptographic implementations. One approach to counteract such attacks is cryptographic schemes based on fresh re-keying. In settings of pre-shared secret keys, such schemes render DPA attacks infeasible by deriving session keys and by ensuring that the attacker cannot collect side-channel leakage on the session key during cryptographic operations with different inputs. This paper present a study on rekeying approach against side channel attacks with current secure schemes and their rekeying functions.
국산 경량 블록 암호 PIPO, HIGHT, CHAM 고속 구현 연구
김인영(Inyeung Kim),석병진(Byoungjin Seok),이창훈(Changhoon Lee) 한국디지털콘텐츠학회 2021 한국디지털콘텐츠학회논문지 Vol.22 No.12
In IoT devices with high communication volume or limited resources, it may be hard to operate lightweight block ciphers. In addition, lightweight ciphers may operate relatively inefficiently in a general-purpose environment due to design principles different from those of general-purpose ciphers. Research on lightweight block encryption algorithms has been actively conducted, but there are relatively few studies on Korean encryption algorithms compared to foreign standard algorithms. Since Korean block ciphers have clear sources of demand due to KCMVP, in this paper conducts research on optimization implementation in lightweight and general-purpose environments targeting Korean lightweight block ciphers. This paper proposes a methodology that applies a CTR mode optimization implementation methodology to any block cipher algorithm and performs CTR mode optimization implementation for PIPO as the proposed methodology. In addition, this paper propose a methodology for applying bitslice implementation techniques to ARX-based cipher algorithms, and bitslice implementation is performed for HIGHT and CHAM algorithms. And the performance of the optimization implementation is checked in an 8-bit, 32-bit and PC environment.
Optimization of 660-nm-Band AlGaInP Laser Diodes by Using Deep-Level Transient Spectroscopy Analyses
Young Chul Shin,김태근,Bum Jun Kim,Byoungjin Ma,Chang Yun Lee,Dong Hoon Kang,Joon Seok Kang,김문덕,Sang Bum Lee,Shi Jong Leem,조수행,Yongjo Park,Young Min Kim 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.3
We report high power and high temperature operation of 660-nm-band AlGaInP laser diodes. The double-channel ridge waveguide structure was used, and the growth conditions for each layer of the AlGaInP laser were optimized to have the lowest defect density by using deep-level transient spectroscopy (DLTS) analyses. The optimized AlGaInP lasers showed better performance than those fabricated without optimization. One of the optimized AlGaInP lasers showed a very stable fundamental transverse mode even at 200 mW and 70 $^{\circ}\mathrm{C}$, a typical threshold current of 64 mA at 660 nm, a slope efficiency of 1.0 W/A, and a characteristic temperature of 212 K. The beam divergences perpendicular and parallel to the junction plane were 15.3$^{\circ}$ and 8.6$^{\circ}$, respectively, at 80 mW CW, which is small enough for a DVD-R/RW system.